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[Music]
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thank you
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Network fundamentals basic Network
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Theory and terminology
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Network fundamentals is our first lesson
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since before we can get into discussing
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networking and its complexity
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we need first need to Define some of the
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terms some of the theory and get a nice
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framework for where we're going to be
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going
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one note about the network plus exam is
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that they assume you have around 18
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months experience in the industry if you
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don't that's okay but I am assuming that
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you do have some basic knowledge of
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computers and perhaps some working
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knowledge of networks so in some cases
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this might be redundant for you and in
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other cases you might be learning some
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new stuff either way I'm going to focus
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on exactly what the network plus exam
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wants to see and
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what you need to know to pass
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so in this module we're going to be
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introduced to networks and what makes up
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a network
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the terminology that's used to describe
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those objects it becomes flexible after
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a little bit of time and experience
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spent on the field but to understand
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what each object does and what its
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functions are in a network I want to
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break down some of the jargon or the
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technical speak and talk about what
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exactly is networking
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so some of the module objectives that
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we're going to cover are first to Define
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and describe a network and a computer
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network you've heard the term Network
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before and so I want to Define what that
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is and how that relates to a computer
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network
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next I want to describe the components
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of a network what makes a computer
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network
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I want to define the terms node and
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server which will be helpful going
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forward when we use those terms
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Define and describe the network backbone
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and the various variations of a network
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backbone and finally
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I want to define the difference between
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a terminal
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a client and a peer
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all right so let's get started
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now because networking is ubiquitous we
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need to define a few specific things in
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order to keep things in order
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so first Network
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this is an interconnected or
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interrelated chain group or system
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generally based on a purpose so for
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instance if we say that you're going to
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Facebook or LinkedIn are social
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networks because the purpose is to be
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social
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and to connect with other people who
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have similar interests likes Etc
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in the same way you are interrelated and
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you form a group
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now based on that a computer network is
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the interconnecting of two or more
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computers that have a basic core purpose
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of communicating electronically
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so the network of social network is to
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communicate with individuals about a
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specific topic on a computer network we
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need to communicate data electronically
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and that's the thing that joins us
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together
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the internet is one really large
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computer network and we will see how
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that comes to play later on in this
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course
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now whether your network is comprised of
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two computers or two thousand computers
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or like the internet two million
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computers there are uh some
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commonalities in networks and
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requirements for what makes them the
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first thing that are needed obviously
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are devices these are the actual
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computers the printers the switches the
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routers all of the devices that are
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going to be connected together by
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media now media can either be a physical
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connection such as copper or newer forms
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such as fiber optics
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or it can be something Wireless like
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Wi-Fi or a radio frequency or even
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cellular Wi-Fi
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each device however has its own language
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when networking and not every device
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knows how to communicate with the
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language of these other devices right
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because obviously a computer
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communicates slightly differently than a
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printer slightly differently than a
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router Etc so in order to allow all
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these devices to communicate with the
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rest of the network we have something
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called a network adapter sometimes
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referred to as a network interface
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controller or a NIC
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specifically in the term of computers
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and it serves this network adapter as a
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translator between the components the
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devices over the media by which the data
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is sent
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so finally to manage and govern how
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everything talks with everything else
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the network needs an operating system
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which is similar to like the ring leader
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in a circus if we can use a a metaphor
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there
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it tells the network how to work
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together in order to perform as
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efficiently as possible over the adapter
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over the media and with each of the
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devices without the operating system
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there wouldn't be any order or Direction
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in the network and no one would really
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know what they were doing so the network
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operating system is responsible really
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for allocating resources
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monitoring the activities of devices on
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the network over the media
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and managing files and data Etc
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now we have two devices that I want to
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Define one is a node and a node is any
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device that is connected to a
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Communications Network
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and this can be just about anything so
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we have uh clients and servers our nodes
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and so are printers and network attached
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storage devices and these are all what
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we call
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endpoint nodes I'm going to write that
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up here
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because that's where the data ends
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whereas something like a router
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or switch or previously we used to see a
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lot of hubs do what's called
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redistribute
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so those are what we call redistribution
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nodes okay so it's important to
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understand that these are both nodes
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anything on the network really any sort
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of device that's communicating is a node
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or being communicated with
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the endpoint nodes where or where the
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information sort of ends up or is going
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to a redistribution node its
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responsibilities to pass the data on to
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another either redistribution node or
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onto the endpoint node
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now a server
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is a network device that's responsible
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for sharing resources and managing
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certain services
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like addressing and we'll talk about
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this which is called an IP address a
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little later
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it's also uh manages devices on the
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network and controls the network-wide
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functions like permissions so not only
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is it going to give uh all our clients
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all the other nodes addresses that allow
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it to communicate it's also going to
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manage how those devices communicate and
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what they're allowed to do which is what
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we call permissions
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all right now this is
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um so you can see that the server is a
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type of node but I just want to describe
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server we're going to talk about some of
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the other
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um devices in just a moment before we do
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that
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let's talk about the network backbone
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okay the network backbone is responsible
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for carrying the majority of network
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traffic and it works very quickly at a
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very very very high speed
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now it might use different technology
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throughout this um on the backbone
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that's different from the rest of the
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network because it basically connects
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all the smaller networks together
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that's why it's called the backbone and
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it needs to be large fast and
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um
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capable of communicating at very high
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speeds because all of these computers
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all these smaller networks are
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communicating we'll talk about how that
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all works in a bit now there are four
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different types of network backbones and
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we're gonna I'm just gonna give you a
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brief definition of these now and we
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will come back and talk about these more
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in depth a little later okay the first
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one is called serial that's where one
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backbone cable
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connects
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to another one after the other
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like so
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all right so there's one backbone cable
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and multiple switches are connected to
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that cable
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which allow devices to connect to it
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there's also something called a
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hierarchical or distributed uh
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um backbone which like a family tree it
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has more of a family tree layout if you
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can imagine right
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okay and this backbone is in this case
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it's much easier to manage typical for
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what we'll call local area networks or
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lands it's much more easily scalable as
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you can see because I can update one
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part a lot faster and in this case the
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backbone is responsible for the traffic
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of the nodes on each branch so we have
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different branches and on each branch
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the backbone is responsible for that and
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that's how it gets a little easier now A
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collapsed uh backbone uses a router as
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the Connecting Point all right and we'll
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talk more about how that works a little
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bit later and what exactly a router does
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and how that's different from a switch
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and that's a pretty major point
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finally we see something called parallel
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which is just like a collapsed uh
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backbone except it has multiple cable
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connections and that's because that
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allows for more redundancy remember if
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you took the A Plus Class we talked
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about redundancy and how we want to make
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sure uh that we don't have what are
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called single points of failures so
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there's more than one cable connection
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which not only is great for redundancy
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it also allows for what's what we call
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load balancing and also a faster
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throughput because the computer can
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decide which of the cable connections to
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use all right so these are again we have
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serial hierarchical or distributed
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collapsed in parallel as we talk more
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about networks these differences will
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become clearer but I just wanted to
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cover them now and you won't probably
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see these specifically on the exam in
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this format you'll see them in other
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formats and but I want to lay the
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framework for what we're going to be
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talking about
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all right now a terminal
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terminal is a network Hardware device
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that's used for entering date data into
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it and displaying data from another
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computer Computing system
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it's commonly called a dummy computer
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because it doesn't have any processing
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capabilities of its own it also doesn't
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have much memory or anything else okay
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so it is literally
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this is a dummy it's basically a screen
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with a keyboard a mouse some sort of
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input tool right and what it's doing is
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simply displaying information on a
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bigger better
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server computer someplace else
287
00:12:09,839 --> 00:12:10,839
all right
288
00:12:13,860 --> 00:12:14,860
we also need something called a terminal
289
00:12:16,079 --> 00:12:17,079
emulator placed onto this computer so
290
00:12:19,200 --> 00:12:20,200
that it can emulate what's going on on
291
00:12:21,180 --> 00:12:22,180
the server and communicate with it since
292
00:12:22,800 --> 00:12:23,800
it doesn't have processing capabilities
293
00:12:24,600 --> 00:12:25,600
or memory of its own now this is
294
00:12:26,940 --> 00:12:27,940
different from what's called a client
295
00:12:30,060 --> 00:12:31,060
a client has its own processor and
296
00:12:33,060 --> 00:12:34,060
memory of its own but it accesses
297
00:12:36,240 --> 00:12:37,240
network resources on other nodes other
298
00:12:39,420 --> 00:12:40,420
servers and other clients
299
00:12:41,459 --> 00:12:42,459
all right so it is um rather than a
300
00:12:44,700 --> 00:12:45,700
server which serves up information the
301
00:12:47,820 --> 00:12:48,820
client takes the information and uses it
302
00:12:51,600 --> 00:12:52,600
now appear
303
00:12:53,639 --> 00:12:54,639
is a network computer that provides its
304
00:12:56,160 --> 00:12:57,160
own resources and services and computes
305
00:12:59,100 --> 00:13:00,100
on its own the best thing about appear
306
00:13:01,740 --> 00:13:02,740
is that it can act it is self-managed
307
00:13:04,680 --> 00:13:05,680
self-contained and it is both a server
308
00:13:09,000 --> 00:13:10,000
and a client
309
00:13:11,880 --> 00:13:12,880
okay
310
00:13:15,180 --> 00:13:16,180
so you can see how this works this
311
00:13:18,240 --> 00:13:19,240
cloth this peer computer serves
312
00:13:20,880 --> 00:13:21,880
information to this peer computer as a
313
00:13:23,399 --> 00:13:24,399
client this computer can serve
314
00:13:26,399 --> 00:13:27,399
information to this one as a client so
315
00:13:28,320 --> 00:13:29,320
this is what we call peer-to-peer
316
00:13:30,240 --> 00:13:31,240
networking it manages its own set of
317
00:13:33,000 --> 00:13:34,000
local policies it has its own set of
318
00:13:35,040 --> 00:13:36,040
users it is completely self-contained
319
00:13:37,680 --> 00:13:38,680
and does not need a server to operate
320
00:13:40,079 --> 00:13:41,079
unlike a client which does
321
00:13:44,399 --> 00:13:45,399
all right
322
00:13:45,600 --> 00:13:46,600
so
323
00:13:47,160 --> 00:13:48,160
just to recap what we've talked about we
324
00:13:49,800 --> 00:13:50,800
were we we defined what a network is and
325
00:13:52,620 --> 00:13:53,620
how that's different slightly from a
326
00:13:54,240 --> 00:13:55,240
computer network which is really what
327
00:13:56,459 --> 00:13:57,459
the network plus exam covers
328
00:13:58,680 --> 00:13:59,680
we describe the components of the
329
00:14:00,839 --> 00:14:01,839
network
330
00:14:02,760 --> 00:14:03,760
uh the adapter
331
00:14:05,220 --> 00:14:06,220
the network operating system the devices
332
00:14:07,920 --> 00:14:08,920
the media let's go ahead and write those
333
00:14:10,380 --> 00:14:11,380
we had media
334
00:14:12,000 --> 00:14:13,000
right which allowed the devices to
335
00:14:14,220 --> 00:14:15,220
communicate
336
00:14:17,180 --> 00:14:18,180
using a network adapter
337
00:14:26,459 --> 00:14:27,459
communicated and managed by an operating
338
00:14:29,220 --> 00:14:30,220
system we also defined a node and server
339
00:14:32,100 --> 00:14:33,100
right the node is really any
340
00:14:35,940 --> 00:14:36,940
um
341
00:14:36,839 --> 00:14:37,839
sort of device that's on we have the end
342
00:14:39,420 --> 00:14:40,420
point
343
00:14:43,079 --> 00:14:44,079
and we also
344
00:14:44,820 --> 00:14:45,820
have a redistribution
345
00:14:51,480 --> 00:14:52,480
we Define and describe the network
346
00:14:53,160 --> 00:14:54,160
backbone remember which is really fast
347
00:15:00,839 --> 00:15:01,839
and the different variations of it which
348
00:15:03,959 --> 00:15:04,959
if you recall included cereal which is
349
00:15:06,480 --> 00:15:07,480
one after the other
350
00:15:08,760 --> 00:15:09,760
hierarchical
351
00:15:13,019 --> 00:15:14,019
also called distributed
352
00:15:20,160 --> 00:15:21,160
then we looked at collapsed
353
00:15:23,519 --> 00:15:24,519
and a more redundant form
354
00:15:25,800 --> 00:15:26,800
parallel
355
00:15:27,720 --> 00:15:28,720
finally we defined terminal client and
356
00:15:30,480 --> 00:15:31,480
appear remember the terminal is a dummy
357
00:15:33,899 --> 00:15:34,899
client accesses resources
358
00:15:38,760 --> 00:15:39,760
on other computers
359
00:15:40,680 --> 00:15:41,680
and appear both serves
360
00:15:44,880 --> 00:15:45,880
and accesses
361
00:15:48,540 --> 00:15:49,540
all right so now that we've covered some
362
00:15:50,459 --> 00:15:51,459
of this basic terminology let's continue
363
00:15:52,560 --> 00:15:53,560
on talking about the fundamentals of a
364
00:15:54,779 --> 00:15:55,779
network And discussing more of what we
365
00:15:57,899 --> 00:15:58,899
need to know in order to get into the
366
00:15:59,519 --> 00:16:00,519
majority of this uh information on the
367
00:16:01,920 --> 00:16:02,920
network plus exam
368
00:16:06,460 --> 00:16:07,460
[Music]
369
00:16:15,139 --> 00:16:16,139
thank you
370
00:16:26,360 --> 00:16:27,360
Network fundamentals Network categories
371
00:16:30,060 --> 00:16:31,060
and models
372
00:16:31,920 --> 00:16:32,920
having discussed some of the basic
373
00:16:33,779 --> 00:16:34,779
components of a network and having
374
00:16:35,880 --> 00:16:36,880
established sort of a baseline of some
375
00:16:37,920 --> 00:16:38,920
terminology that we all need to be
376
00:16:39,300 --> 00:16:40,300
familiar with I now want to talk about
377
00:16:41,399 --> 00:16:42,399
the different categories of networks and
378
00:16:44,519 --> 00:16:45,519
as we begin to understand the
379
00:16:46,079 --> 00:16:47,079
differences between these categories
380
00:16:47,759 --> 00:16:48,759
we're also going to look at some of the
381
00:16:49,440 --> 00:16:50,440
basic models that networks are placed
382
00:16:52,139 --> 00:16:53,139
into depending on different
383
00:16:53,579 --> 00:16:54,579
configurations and layouts
384
00:16:55,920 --> 00:16:56,920
so our objectives in this module are
385
00:16:59,339 --> 00:17:00,339
first to describe the characteristics of
386
00:17:02,040 --> 00:17:03,040
a lan or what's called a local
387
00:17:06,540 --> 00:17:07,540
area network now this is different from
388
00:17:10,140 --> 00:17:11,140
a Wan or a wide area network you're
389
00:17:13,799 --> 00:17:14,799
going to need to be familiar with both
390
00:17:14,939 --> 00:17:15,939
of these terms and actually we're going
391
00:17:16,260 --> 00:17:17,260
to see a few different types of lands
392
00:17:19,220 --> 00:17:20,220
including uh man's
393
00:17:23,220 --> 00:17:24,220
pans
394
00:17:26,880 --> 00:17:27,880
cans
395
00:17:28,860 --> 00:17:29,860
and uh none of these are what you think
396
00:17:31,679 --> 00:17:32,679
these are all acronyms so a man is a
397
00:17:34,020 --> 00:17:35,020
metropolitan or a municipal area network
398
00:17:36,380 --> 00:17:37,380
uh pan is a personal area network can
399
00:17:39,299 --> 00:17:40,299
campus area network etc etc and as you
400
00:17:41,940 --> 00:17:42,940
can see from the name these these terms
401
00:17:44,160 --> 00:17:45,160
are really
402
00:17:45,240 --> 00:17:46,240
um amorphous so it really depends on
403
00:17:48,539 --> 00:17:49,539
some subjective uh opinions as to what
404
00:17:51,480 --> 00:17:52,480
these
405
00:17:52,500 --> 00:17:53,500
types of networks really described but
406
00:17:55,140 --> 00:17:56,140
anyway we're going to cover all of those
407
00:17:56,580 --> 00:17:57,580
so you'll be prepared for them if if and
408
00:17:58,320 --> 00:17:59,320
when you see them out in the field or on
409
00:17:59,820 --> 00:18:00,820
the test we're also going to define the
410
00:18:01,679 --> 00:18:02,679
difference between the internet
411
00:18:02,580 --> 00:18:03,580
something that I'm sure you all have
412
00:18:04,200 --> 00:18:05,200
heard of and then two other terms the
413
00:18:06,419 --> 00:18:07,419
intranet and the extranat which are more
414
00:18:10,380 --> 00:18:11,380
uh specific towards organizations and
415
00:18:14,039 --> 00:18:15,039
sort of uh uh using internet
416
00:18:16,760 --> 00:18:17,760
Technologies uh for a specific
417
00:18:19,260 --> 00:18:20,260
organization we're then going to look at
418
00:18:21,780 --> 00:18:22,780
uh the way networks basically are
419
00:18:24,660 --> 00:18:25,660
organized we're going to look at
420
00:18:26,039 --> 00:18:27,039
something called a centralized Network
421
00:18:28,020 --> 00:18:29,020
which if you recall from the previous uh
422
00:18:31,260 --> 00:18:32,260
video is going to involve a terminal and
423
00:18:35,340 --> 00:18:36,340
a Mainframe and then we're going to look
424
00:18:37,740 --> 00:18:38,740
at a client server Network which sort of
425
00:18:40,380 --> 00:18:41,380
takes the pressure off of that Central
426
00:18:42,500 --> 00:18:43,500
Mainframe and puts it onto a server with
427
00:18:46,140 --> 00:18:47,140
a client and then finally we're going to
428
00:18:48,179 --> 00:18:49,179
look at what a peer-to-peer network is
429
00:18:49,980 --> 00:18:50,980
and again that is like where we have all
430
00:18:52,559 --> 00:18:53,559
clients no servers so we're really
431
00:18:54,660 --> 00:18:55,660
looking at a descending order of
432
00:18:56,760 --> 00:18:57,760
centralization but at the same time
433
00:18:58,860 --> 00:18:59,860
we're putting more power and resources
434
00:19:01,260 --> 00:19:02,260
into the individual computer finally
435
00:19:03,840 --> 00:19:04,840
because nothing is as simple as it seems
436
00:19:06,240 --> 00:19:07,240
we're going to look at what's called a
437
00:19:08,280 --> 00:19:09,280
mixed mode Network which is a
438
00:19:10,080 --> 00:19:11,080
combination of sort of all of these and
439
00:19:12,960 --> 00:19:13,960
that'll help us as we go forward
440
00:19:15,419 --> 00:19:16,419
understand how an administrator of a
441
00:19:18,480 --> 00:19:19,480
network something we'll also talk about
442
00:19:20,840 --> 00:19:21,840
uh deals with these different types of
443
00:19:23,940 --> 00:19:24,940
needs on their entire network
444
00:19:27,660 --> 00:19:28,660
so let's first start talking about a
445
00:19:30,120 --> 00:19:31,120
local area network a lan or a local area
446
00:19:33,299 --> 00:19:34,299
network is a network that spans a small
447
00:19:36,539 --> 00:19:37,539
area typically either a building like
448
00:19:39,900 --> 00:19:40,900
your home or office or a floor of a much
449
00:19:43,140 --> 00:19:44,140
larger building you might find this in
450
00:19:46,200 --> 00:19:47,200
like a skyscraper so take the Empire
451
00:19:49,140 --> 00:19:50,140
State Building for instance which is one
452
00:19:51,660 --> 00:19:52,660
of the largest or tallest buildings in
453
00:19:54,480 --> 00:19:55,480
New York or it used to be
454
00:19:56,580 --> 00:19:57,580
um
455
00:19:57,419 --> 00:19:58,419
every floor of the building might have a
456
00:20:01,380 --> 00:20:02,380
different company using it so each one
457
00:20:03,960 --> 00:20:04,960
of those has their own land or local
458
00:20:07,020 --> 00:20:08,020
area network to keep them separated from
459
00:20:09,600 --> 00:20:10,600
one another even though they might even
460
00:20:11,640 --> 00:20:12,640
be using some of the same infrastructure
461
00:20:13,860 --> 00:20:14,860
running into that building now in a land
462
00:20:17,340 --> 00:20:18,340
the most commonly implemented technology
463
00:20:19,500 --> 00:20:20,500
and something you've probably heard of
464
00:20:20,760 --> 00:20:21,760
is something called ethernet and this
465
00:20:23,280 --> 00:20:24,280
means that the communication path taken
466
00:20:25,260 --> 00:20:26,260
utilizes uh cabling or short range
467
00:20:28,440 --> 00:20:29,440
Wireless Technologies we're going to
468
00:20:30,840 --> 00:20:31,840
talk about ethernet and and really what
469
00:20:32,940 --> 00:20:33,940
it means because it's it's also not just
470
00:20:34,799 --> 00:20:35,799
the hardware it really has to do with
471
00:20:36,240 --> 00:20:37,240
how the data is being communicated in
472
00:20:38,820 --> 00:20:39,820
Greater detail in an upcoming module now
473
00:20:41,400 --> 00:20:42,400
in a local area network a connection uh
474
00:20:44,820 --> 00:20:45,820
is leased by a service provider but it
475
00:20:47,700 --> 00:20:48,700
isn't necessarily for the land to
476
00:20:49,440 --> 00:20:50,440
function properly so this means I don't
477
00:20:51,539 --> 00:20:52,539
need an outside sort of connection in
478
00:20:54,960 --> 00:20:55,960
order for my land to work the reason I
479
00:20:57,179 --> 00:20:58,179
might need a connection to the outside
480
00:21:00,299 --> 00:21:01,299
from an internet service provider is
481
00:21:03,000 --> 00:21:04,000
going to be thanks to a Wan or a wide
482
00:21:06,419 --> 00:21:07,419
area network but let's talk really
483
00:21:08,100 --> 00:21:09,100
quickly about land administrators the
484
00:21:10,620 --> 00:21:11,620
people who are running these lands that
485
00:21:12,120 --> 00:21:13,120
might help us understand them a little
486
00:21:13,799 --> 00:21:14,799
clearer
487
00:21:15,419 --> 00:21:16,419
now land administrators are like
488
00:21:18,059 --> 00:21:19,059
jugglers they have to keep their eyes on
489
00:21:20,280 --> 00:21:21,280
all of the components of their Network
490
00:21:21,960 --> 00:21:22,960
at the same time hence the little GIF
491
00:21:25,080 --> 00:21:26,080
over here they have to have there for a
492
00:21:27,960 --> 00:21:28,960
broad range of versatile skills that
493
00:21:30,840 --> 00:21:31,840
allow them to manage and maintain all
494
00:21:33,000 --> 00:21:34,000
the different parts of their Network now
495
00:21:35,940 --> 00:21:36,940
that's only within their domain and the
496
00:21:39,000 --> 00:21:40,000
juggler also has to be mindful of each
497
00:21:41,580 --> 00:21:42,580
of the objects in the air at the same
498
00:21:43,080 --> 00:21:44,080
time or else they might lose track of
499
00:21:45,480 --> 00:21:46,480
one or all of them like the juggler if
500
00:21:48,960 --> 00:21:49,960
the land administrator loses track of
501
00:21:51,360 --> 00:21:52,360
one part of their job it's likely the
502
00:21:54,120 --> 00:21:55,120
entire network of moving components
503
00:21:56,400 --> 00:21:57,400
could come quote unquote crashing to a
504
00:21:59,039 --> 00:22:00,039
halt the land administrator therefore
505
00:22:01,559 --> 00:22:02,559
has to have a strong working knowledge
506
00:22:04,020 --> 00:22:05,020
of all the aspects of their Network now
507
00:22:06,720 --> 00:22:07,720
the land administrator should be able to
508
00:22:08,460 --> 00:22:09,460
handle tasks such as installation of
509
00:22:11,280 --> 00:22:12,280
software and hardware
510
00:22:13,280 --> 00:22:14,280
troubleshooting all components of the
511
00:22:15,780 --> 00:22:16,780
network including the servers which
512
00:22:17,460 --> 00:22:18,460
we'll talk about connectivity devices
513
00:22:19,919 --> 00:22:20,919
and media and so on and so forth and not
514
00:22:23,280 --> 00:22:24,280
to mention security for the network so
515
00:22:26,580 --> 00:22:27,580
if that isn't enough one of their most
516
00:22:29,280 --> 00:22:30,280
difficult tasking duties of the land
517
00:22:31,679 --> 00:22:32,679
administrator is being responsible for
518
00:22:33,720 --> 00:22:34,720
users and attending to their requests
519
00:22:36,539 --> 00:22:37,539
and their requirements so
520
00:22:39,000 --> 00:22:40,000
you can tell that the land administrator
521
00:22:41,280 --> 00:22:42,280
really has to be able to do a lot and
522
00:22:44,039 --> 00:22:45,039
we're gonna as we go through this course
523
00:22:45,840 --> 00:22:46,840
you'll see more and more specifically of
524
00:22:48,120 --> 00:22:49,120
what they have to do but let's talk
525
00:22:49,919 --> 00:22:50,919
about a Wan a Wan or a wide area network
526
00:22:54,299 --> 00:22:55,299
uh is a network that spans a larger
527
00:22:57,120 --> 00:22:58,120
geographical area than a lan in most
528
00:23:00,179 --> 00:23:01,179
cases uh the WAN is going to connect as
529
00:23:04,140 --> 00:23:05,140
this picture demonstrates multiple lands
530
00:23:07,020 --> 00:23:08,020
together and it might even utilize
531
00:23:09,380 --> 00:23:10,380
long-range communication such as
532
00:23:11,760 --> 00:23:12,760
satellite or radio frequency otherwise
533
00:23:14,760 --> 00:23:15,760
known as RF
534
00:23:21,360 --> 00:23:22,360
now one main factor that differentiates
535
00:23:23,760 --> 00:23:24,760
a win or wide area network from a lan is
536
00:23:26,820 --> 00:23:27,820
that it can enable users to connect to
537
00:23:28,620 --> 00:23:29,620
one another from different physical
538
00:23:30,360 --> 00:23:31,360
locations so whereas these are each
539
00:23:33,000 --> 00:23:34,000
physically sort of uh isolated in some
540
00:23:36,000 --> 00:23:37,000
ways you can tell the WAN connects all
541
00:23:39,059 --> 00:23:40,059
of these lands together
542
00:23:42,840 --> 00:23:43,840
okay now a Wan can be private where an
543
00:23:46,799 --> 00:23:47,799
organization has complete control of
544
00:23:49,380 --> 00:23:50,380
access to it resources and it's solely
545
00:23:52,799 --> 00:23:53,799
responsible for everything that occurs
546
00:23:54,659 --> 00:23:55,659
on that Network or a win can be public
547
00:23:57,840 --> 00:23:58,840
and of course the world's largest Wan
548
00:24:02,220 --> 00:24:03,220
is the internet
549
00:24:04,260 --> 00:24:05,260
now we're going to talk more about the
550
00:24:05,580 --> 00:24:06,580
internet in detail shortly but I just
551
00:24:07,260 --> 00:24:08,260
want to point out that the biggest wide
552
00:24:09,299 --> 00:24:10,299
area network we have is the WAN and
553
00:24:12,780 --> 00:24:13,780
unlike the land which is geographically
554
00:24:15,600 --> 00:24:16,600
isolated and can be controlled by a
555
00:24:19,020 --> 00:24:20,020
relatively few number of people the WAN
556
00:24:21,419 --> 00:24:22,419
has very different needs
557
00:24:23,820 --> 00:24:24,820
now there are also different types of
558
00:24:25,980 --> 00:24:26,980
lands that are out there now some of
559
00:24:27,480 --> 00:24:28,480
these classifications
560
00:24:29,460 --> 00:24:30,460
um we might get argument from certain
561
00:24:32,100 --> 00:24:33,100
individuals just because this is sort of
562
00:24:35,280 --> 00:24:36,280
open to some subjectivity but these are
563
00:24:37,260 --> 00:24:38,260
covered on the examine which is the
564
00:24:39,240 --> 00:24:40,240
reason I want to make sure we cover them
565
00:24:41,039 --> 00:24:42,039
the first one that we've seen a few
566
00:24:43,140 --> 00:24:44,140
times when we talked if you were here
567
00:24:45,000 --> 00:24:46,000
for a plus is called a pan or a personal
568
00:24:47,580 --> 00:24:48,580
area network a pan is two to three
569
00:24:50,820 --> 00:24:51,820
computers connected together by cables
570
00:24:53,520 --> 00:24:54,520
and a wireless pan or wpn is going to be
571
00:24:58,140 --> 00:24:59,140
using Bluetooth or infrared Technologies
572
00:25:00,720 --> 00:25:01,720
generally speaking when we are talking
573
00:25:03,299 --> 00:25:04,299
about pans uh for purposes of the exam
574
00:25:06,419 --> 00:25:07,419
we're really talking about Bluetooth now
575
00:25:09,720 --> 00:25:10,720
I might consider pan a sort of local
576
00:25:12,179 --> 00:25:13,179
area network but
577
00:25:14,520 --> 00:25:15,520
for our sake we're just gonna group this
578
00:25:16,919 --> 00:25:17,919
into wands right now but this could be
579
00:25:18,780 --> 00:25:19,780
considered something a little different
580
00:25:20,520 --> 00:25:21,520
okay so I'm just gonna sort of put
581
00:25:22,320 --> 00:25:23,320
brackets around that and a w pan or a
582
00:25:25,559 --> 00:25:26,559
wireless pan if we put that W in front
583
00:25:28,260 --> 00:25:29,260
of it uh occurs when the computers are
584
00:25:30,840 --> 00:25:31,840
connected together wirelessly but not
585
00:25:33,659 --> 00:25:34,659
through an access point right so they're
586
00:25:36,779 --> 00:25:37,779
connected literally uh to one another
587
00:25:39,860 --> 00:25:40,860
thanks to the wireless technology but
588
00:25:43,440 --> 00:25:44,440
there is no sort of Central Access Point
589
00:25:45,840 --> 00:25:46,840
that they all connect to
590
00:25:47,760 --> 00:25:48,760
now the next type is a can or a campus
591
00:25:50,700 --> 00:25:51,700
area network and I'm assuming from the
592
00:25:53,360 --> 00:25:54,360
name you can guess that this is a Wan
593
00:25:56,580 --> 00:25:57,580
that spans the geographical area
594
00:25:58,500 --> 00:25:59,500
comparable to like a school or a campus
595
00:26:02,940 --> 00:26:03,940
or a business park such as Yahoo now
596
00:26:05,880 --> 00:26:06,880
again some people might consider this a
597
00:26:07,980 --> 00:26:08,980
land some might consider this a win but
598
00:26:10,559 --> 00:26:11,559
for our sake we're just going to assume
599
00:26:13,200 --> 00:26:14,200
that this is dealing with some sort of
600
00:26:15,120 --> 00:26:16,120
Campus some sort of school some sort of
601
00:26:17,820 --> 00:26:18,820
area that is contained all by one
602
00:26:20,940 --> 00:26:21,940
organization so for instance if I had uh
603
00:26:24,179 --> 00:26:25,179
four buildings all connected
604
00:26:29,039 --> 00:26:30,039
uh and each of them has let's say four
605
00:26:32,220 --> 00:26:33,220
floors
606
00:26:34,260 --> 00:26:35,260
right there might be a lan on each floor
607
00:26:36,960 --> 00:26:37,960
or in each building and then connecting
608
00:26:39,600 --> 00:26:40,600
each land together is going to be this
609
00:26:41,580 --> 00:26:42,580
can which is a sort of wide area network
610
00:26:43,559 --> 00:26:44,559
but because the wide area network could
611
00:26:45,840 --> 00:26:46,840
denote uh the internet and the cloud is
612
00:26:49,620 --> 00:26:50,620
sort of the best descriptor of that we
613
00:26:52,620 --> 00:26:53,620
want to call it something slightly
614
00:26:53,820 --> 00:26:54,820
different now a man is a metropolitan or
615
00:26:57,720 --> 00:26:58,720
it could also be a municipal
616
00:27:01,559 --> 00:27:02,559
area network
617
00:27:03,299 --> 00:27:04,299
and as the name implies It's relatively
618
00:27:06,360 --> 00:27:07,360
the size of a city or a town or a
619
00:27:09,539 --> 00:27:10,539
metropolitan area so if I have a
620
00:27:11,640 --> 00:27:12,640
business that like the cam uh has
621
00:27:14,520 --> 00:27:15,520
several buildings but the buildings are
622
00:27:16,080 --> 00:27:17,080
now separated over the course of the
623
00:27:18,720 --> 00:27:19,720
city as opposed to some in my own campus
624
00:27:20,760 --> 00:27:21,760
then I'm probably going to use this
625
00:27:22,440 --> 00:27:23,440
terminology again or a global area
626
00:27:25,559 --> 00:27:26,559
network I think it's sort of redundant
627
00:27:27,480 --> 00:27:28,480
but these are networks that go from
628
00:27:30,600 --> 00:27:31,600
country to country or around uh
629
00:27:37,500 --> 00:27:38,500
these are networks that go all the way
630
00:27:39,659 --> 00:27:40,659
from country to country all the way
631
00:27:41,340 --> 00:27:42,340
around the world they span the globe and
632
00:27:44,039 --> 00:27:45,039
they're going to utilize Technologies uh
633
00:27:46,919 --> 00:27:47,919
like satellite probably and the reason
634
00:27:49,799 --> 00:27:50,799
we're going to call this uh again is
635
00:27:52,440 --> 00:27:53,440
because generally speaking the global
636
00:27:54,480 --> 00:27:55,480
area network again is all controlled by
637
00:27:57,480 --> 00:27:58,480
one sort of company
638
00:28:07,440 --> 00:28:08,440
as opposed to a Wan which as we just
639
00:28:09,600 --> 00:28:10,600
discussed could include either all being
640
00:28:12,360 --> 00:28:13,360
controlled by one company or
641
00:28:14,400 --> 00:28:15,400
all being controlled by uh you know
642
00:28:17,400 --> 00:28:18,400
disparate companies such as the internet
643
00:28:19,159 --> 00:28:20,159
finally an En which is the only one that
644
00:28:23,220 --> 00:28:24,220
breaks from this convention is called an
645
00:28:25,860 --> 00:28:26,860
Enterprise Network it's a network that
646
00:28:28,020 --> 00:28:29,020
includes usually aspects of both a Wan
647
00:28:30,900 --> 00:28:31,900
and a lan and it's typically owned and
648
00:28:33,659 --> 00:28:34,659
operated by a single entity or
649
00:28:35,820 --> 00:28:36,820
organization just like a gan might be
650
00:28:38,460 --> 00:28:39,460
now again these terms are very fluid and
651
00:28:41,460 --> 00:28:42,460
flexible and depending on who you talk
652
00:28:43,620 --> 00:28:44,620
to they'll call it different things so
653
00:28:45,179 --> 00:28:46,179
you might I worked for a an organization
654
00:28:47,880 --> 00:28:48,880
we never used the word man we always use
655
00:28:51,059 --> 00:28:52,059
the word when talking about the network
656
00:28:53,580 --> 00:28:54,580
that was deployed over the entire city
657
00:28:55,740 --> 00:28:56,740
however certain individuals certain
658
00:28:57,900 --> 00:28:58,900
organizations will call these different
659
00:28:59,460 --> 00:29:00,460
things and the names might change as
660
00:29:01,080 --> 00:29:02,080
well but it's important to have a firm
661
00:29:03,960 --> 00:29:04,960
understanding of this just from a basic
662
00:29:07,620 --> 00:29:08,620
you know definition standpoint but also
663
00:29:10,260 --> 00:29:11,260
so that if you go out in the fields and
664
00:29:11,460 --> 00:29:12,460
you hear people talking these different
665
00:29:12,659 --> 00:29:13,659
terms you can talk the talk as well
666
00:29:17,400 --> 00:29:18,400
now unlike land administrators whose
667
00:29:20,159 --> 00:29:21,159
Duties are quite varied when
668
00:29:22,440 --> 00:29:23,440
administrators are typically specialists
669
00:29:24,840 --> 00:29:25,840
in their respective Fields so they're
670
00:29:27,000 --> 00:29:28,000
responsible for more complex
671
00:29:28,559 --> 00:29:29,559
infrastructures and as a result uh they
672
00:29:31,559 --> 00:29:32,559
need to be more fluent in say routing
673
00:29:33,539 --> 00:29:34,539
structures and troubleshooting different
674
00:29:35,159 --> 00:29:36,159
difficult or different network issues
675
00:29:37,679 --> 00:29:38,679
they're also responsible for say data
676
00:29:40,679 --> 00:29:41,679
versus voice systems and when
677
00:29:43,260 --> 00:29:44,260
administrators concentrate generally on
678
00:29:45,779 --> 00:29:46,779
network oriented problems and not user
679
00:29:48,539 --> 00:29:49,539
related issues like a land administrator
680
00:29:50,760 --> 00:29:51,760
so with a a lan we're really going to
681
00:29:54,240 --> 00:29:55,240
get these user-oriented tasks right
682
00:29:56,580 --> 00:29:57,580
because they're dealing with the user on
683
00:29:58,200 --> 00:29:59,200
a day-to-day basic a Wan administrator
684
00:30:00,600 --> 00:30:01,600
is really not dealing with these or
685
00:30:01,860 --> 00:30:02,860
they're dealing with sometimes what we
686
00:30:03,000 --> 00:30:04,000
would refer to as the back end and in
687
00:30:06,360 --> 00:30:07,360
some cases as well they're also going to
688
00:30:08,700 --> 00:30:09,700
be a little more specialized in what
689
00:30:11,279 --> 00:30:12,279
they do since what they're dealing with
690
00:30:13,140 --> 00:30:14,140
is a lot more complex a lan
691
00:30:15,000 --> 00:30:16,000
administrator can sort of be a jack of
692
00:30:16,980 --> 00:30:17,980
all trades a wand administrator we want
693
00:30:19,500 --> 00:30:20,500
to be a master of exactly what it is he
694
00:30:21,600 --> 00:30:22,600
or she is dealing with
695
00:30:23,279 --> 00:30:24,279
uh one of the other main duties of a Wan
696
00:30:26,220 --> 00:30:27,220
administrator is the development and
697
00:30:28,260 --> 00:30:29,260
implementation of certain scripts that
698
00:30:30,899 --> 00:30:31,899
are going to automate certain Network
699
00:30:32,580 --> 00:30:33,580
processes and they're also going to plan
700
00:30:35,520 --> 00:30:36,520
for and test and push out upgrades and
701
00:30:38,159 --> 00:30:39,159
updates to the infrastructure of the
702
00:30:40,620 --> 00:30:41,620
network network wide whereas a land
703
00:30:42,419 --> 00:30:43,419
administrator is going to do this on a
704
00:30:44,820 --> 00:30:45,820
sort of local basis perhaps to the
705
00:30:46,860 --> 00:30:47,860
computers in their Network so we can see
706
00:30:49,380 --> 00:30:50,380
sort of how these are getting
707
00:30:50,960 --> 00:30:51,960
differentiated here a Wan administrators
708
00:30:53,940 --> 00:30:54,940
a lot more specialized and they're not
709
00:30:57,779 --> 00:30:58,779
focused on user oriented
710
00:31:00,480 --> 00:31:01,480
tasks they're looking at Network stuff
711
00:31:02,940 --> 00:31:03,940
so you can see a Wan administrator again
712
00:31:05,039 --> 00:31:06,039
dealing with the back end much more
713
00:31:07,140 --> 00:31:08,140
specifically generally more Technical
714
00:31:08,940 --> 00:31:09,940
and generally also a little bit more
715
00:31:10,919 --> 00:31:11,919
training than a land administrator
716
00:31:14,399 --> 00:31:15,399
now let's talk about the internet or the
717
00:31:16,740 --> 00:31:17,740
World Wide Web which is a public wide
718
00:31:20,100 --> 00:31:21,100
area network right it is the largest Wan
719
00:31:24,419 --> 00:31:25,419
that we have and it essentially connects
720
00:31:27,059 --> 00:31:28,059
every country on the planet in some ways
721
00:31:29,279 --> 00:31:30,279
every computer on the planet it's used
722
00:31:31,740 --> 00:31:32,740
for many different things including but
723
00:31:33,720 --> 00:31:34,720
certainly not limited to sending and
724
00:31:35,820 --> 00:31:36,820
receiving email initiating and
725
00:31:38,399 --> 00:31:39,399
completing commercial and private
726
00:31:40,460 --> 00:31:41,460
transactions uh commute communicating
727
00:31:44,039 --> 00:31:45,039
and allowing people to connect to one
728
00:31:46,500 --> 00:31:47,500
another that are sitting in the same
729
00:31:48,360 --> 00:31:49,360
room or perhaps even on the other side
730
00:31:50,399 --> 00:31:51,399
of the world the internet is really the
731
00:31:52,380 --> 00:31:53,380
method by which everyone in the world
732
00:31:53,880 --> 00:31:54,880
can communicate in one way or the other
733
00:31:56,580 --> 00:31:57,580
and in some ways we can actually use it
734
00:31:59,279 --> 00:32:00,279
to create our own virtual lands that are
735
00:32:02,220 --> 00:32:03,220
private and we'll talk more about that
736
00:32:04,020 --> 00:32:05,020
the other thing that's important to know
737
00:32:05,820 --> 00:32:06,820
is every bit of data is stored somewhere
738
00:32:09,240 --> 00:32:10,240
on a server typically in the form of a
739
00:32:11,820 --> 00:32:12,820
web page and in order to access the data
740
00:32:14,340 --> 00:32:15,340
data on the internet you're going to
741
00:32:16,559 --> 00:32:17,559
have several different considerations
742
00:32:19,020 --> 00:32:20,020
that are going to be made first of all
743
00:32:21,179 --> 00:32:22,179
you need to have a web browser of some
744
00:32:24,240 --> 00:32:25,240
sort
745
00:32:26,039 --> 00:32:27,039
or you're gonna need to utilize a
746
00:32:27,720 --> 00:32:28,720
certain generic protocol and have
747
00:32:29,520 --> 00:32:30,520
something like uh so if we're talking a
748
00:32:31,740 --> 00:32:32,740
web browser we're gonna need to use a
749
00:32:33,059 --> 00:32:34,059
safari Internet Explorer Google Chrome
750
00:32:34,799 --> 00:32:35,799
Firefox
751
00:32:36,480 --> 00:32:37,480
Etc but they're all using HTTP which is
752
00:32:40,260 --> 00:32:41,260
a specific protocol and it has a certain
753
00:32:42,960 --> 00:32:43,960
port
754
00:32:44,399 --> 00:32:45,399
which by the way is 80. we'll talk more
755
00:32:46,620 --> 00:32:47,620
about those later in order to allow
756
00:32:48,840 --> 00:32:49,840
communication to occur and this might be
757
00:32:51,120 --> 00:32:52,120
different from say another form of
758
00:32:52,919 --> 00:32:53,919
communication such as FTP or remoting in
759
00:32:55,860 --> 00:32:56,860
and so on and secondly all devices that
760
00:32:58,500 --> 00:32:59,500
want to connect to the internet must be
761
00:33:00,899 --> 00:33:01,899
assigned we would call an IP address all
762
00:33:04,440 --> 00:33:05,440
things on the internet due to the way it
763
00:33:06,600 --> 00:33:07,600
works are governed by this IP or the
764
00:33:09,419 --> 00:33:10,419
Internet Protocol we're going to revisit
765
00:33:11,700 --> 00:33:12,700
this in a future module but IP
766
00:33:16,220 --> 00:33:17,220
allows all of this to happen if it
767
00:33:19,380 --> 00:33:20,380
wasn't 4ip we wouldn't have an internet
768
00:33:21,419 --> 00:33:22,419
at least in the way we know it so again
769
00:33:23,700 --> 00:33:24,700
the internet is this largest global wide
770
00:33:27,720 --> 00:33:28,720
area network that we have in the world
771
00:33:30,000 --> 00:33:31,000
and it's for use it's public and
772
00:33:32,519 --> 00:33:33,519
everyone can use it if they you know
773
00:33:34,559 --> 00:33:35,559
have a provider that gives them access
774
00:33:36,360 --> 00:33:37,360
now this is different from an intranet
775
00:33:39,059 --> 00:33:40,059
an intranet is a company's private
776
00:33:42,419 --> 00:33:43,419
version of the Internet it's commonly
777
00:33:45,059 --> 00:33:46,059
connected to the internet so that people
778
00:33:47,159 --> 00:33:48,159
can uh connect even if they're not
779
00:33:49,679 --> 00:33:50,679
locally at the same place physically but
780
00:33:52,440 --> 00:33:53,440
the purpose of an intranet is to keep
781
00:33:54,419 --> 00:33:55,419
your network or portions of your network
782
00:33:56,580 --> 00:33:57,580
segregated from the unsecure and
783
00:33:59,460 --> 00:34:00,460
possibly even dangerous internet so a
784
00:34:02,100 --> 00:34:03,100
company might use an intranet for
785
00:34:04,080 --> 00:34:05,080
security purposes or for confidentiality
786
00:34:07,860 --> 00:34:08,860
if they have certain files and folders
787
00:34:09,720 --> 00:34:10,720
they want to post up and the intranet
788
00:34:11,639 --> 00:34:12,639
uses the same services and protocols as
789
00:34:14,520 --> 00:34:15,520
the internet so the reason it shares
790
00:34:16,500 --> 00:34:17,500
this name is intra enter to the
791
00:34:19,859 --> 00:34:20,859
organization but it shares the same name
792
00:34:22,080 --> 00:34:23,080
because it's using all of the same
793
00:34:23,940 --> 00:34:24,940
services in other words IP HTTP you
794
00:34:27,300 --> 00:34:28,300
still use a browser so on and so forth
795
00:34:29,580 --> 00:34:30,580
so it's still accessed the same way you
796
00:34:32,460 --> 00:34:33,460
would the internet through a browser and
797
00:34:34,440 --> 00:34:35,440
a web page on the world wide web now all
798
00:34:37,560 --> 00:34:38,560
of this is different from an Extranet as
799
00:34:40,080 --> 00:34:41,080
the name implies
800
00:34:41,839 --> 00:34:42,839
with an intranet your network is
801
00:34:44,460 --> 00:34:45,460
completely secure from the internet
802
00:34:46,260 --> 00:34:47,260
right you control who has access to your
803
00:34:48,839 --> 00:34:49,839
network in every facet
804
00:34:50,580 --> 00:34:51,580
but what if your company organization
805
00:34:54,480 --> 00:34:55,480
needs to allow certain individuals to
806
00:34:57,060 --> 00:34:58,060
have access to your network but you
807
00:34:58,980 --> 00:34:59,980
don't want them to have access to all of
808
00:35:01,260 --> 00:35:02,260
your network in this case we're going to
809
00:35:03,420 --> 00:35:04,420
use something called an Extranet it
810
00:35:05,520 --> 00:35:06,520
gives you the ability to Grant uh access
811
00:35:08,700 --> 00:35:09,700
to specific portions of your network and
812
00:35:11,760 --> 00:35:12,760
your Extranet so you can give access to
813
00:35:14,880 --> 00:35:15,880
specific people typically vendors
814
00:35:16,920 --> 00:35:17,920
suppliers individuals that might need
815
00:35:20,400 --> 00:35:21,400
minimal or temporary access at the same
816
00:35:23,220 --> 00:35:24,220
time your Extranet is restricting them
817
00:35:25,680 --> 00:35:26,680
from having full access to the rest of
818
00:35:27,480 --> 00:35:28,480
your network or your intranet so it's
819
00:35:31,500 --> 00:35:32,500
really an extension of your intranet but
820
00:35:35,339 --> 00:35:36,339
it's the part that is exterior look at
821
00:35:37,859 --> 00:35:38,859
that extra
822
00:35:39,599 --> 00:35:40,599
to your organization so again the
823
00:35:41,520 --> 00:35:42,520
internet
824
00:35:42,540 --> 00:35:43,540
is is a you know using a certain degree
825
00:35:45,780 --> 00:35:46,780
of protocols and uh technologies that
826
00:35:49,500 --> 00:35:50,500
allows anyone in the world to access
827
00:35:50,880 --> 00:35:51,880
information the intranet is sort of a
828
00:35:54,359 --> 00:35:55,359
private internet for your organization
829
00:35:56,820 --> 00:35:57,820
and the Extranet is the part of that
830
00:35:59,339 --> 00:36:00,339
intranet that you're going to let other
831
00:36:01,680 --> 00:36:02,680
people from outside of your organization
832
00:36:03,839 --> 00:36:04,839
have access to
833
00:36:08,460 --> 00:36:09,460
now I just want to Define what a segment
834
00:36:11,460 --> 00:36:12,460
is since we might see this term come up
835
00:36:14,099 --> 00:36:15,099
a bit in the future a segment is a
836
00:36:17,040 --> 00:36:18,040
portion of a Network that has linked
837
00:36:19,500 --> 00:36:20,500
devices and that are separated by a
838
00:36:22,079 --> 00:36:23,079
connectivity device such as a switch or
839
00:36:24,839 --> 00:36:25,839
a router
840
00:36:26,099 --> 00:36:27,099
all right so we haven't talked about
841
00:36:27,900 --> 00:36:28,900
switches and routers yet but we're going
842
00:36:29,880 --> 00:36:30,880
to and so what I mean is I might have a
843
00:36:32,280 --> 00:36:33,280
lan
844
00:36:34,859 --> 00:36:35,859
okay and
845
00:36:38,220 --> 00:36:39,220
let's say that for simplicity's sake My
846
00:36:41,099 --> 00:36:42,099
Lan is consisting of four computers all
847
00:36:44,040 --> 00:36:45,040
connected through a central device
848
00:36:48,359 --> 00:36:49,359
which we're going to call a switch
849
00:36:52,740 --> 00:36:53,740
now remember if they weren't connecting
850
00:36:54,180 --> 00:36:55,180
through that Central device this would
851
00:36:55,560 --> 00:36:56,560
be called a pan a personal area network
852
00:36:57,839 --> 00:36:58,839
but this is a lan has a central device
853
00:36:59,460 --> 00:37:00,460
and let's say this Central device
854
00:37:02,520 --> 00:37:03,520
and this I'm really simplifying it but
855
00:37:05,280 --> 00:37:06,280
let's say it connects to another switch
856
00:37:09,300 --> 00:37:10,300
and that other switch
857
00:37:11,820 --> 00:37:12,820
has four computers connected to it now I
858
00:37:15,119 --> 00:37:16,119
have different segments of my network
859
00:37:18,200 --> 00:37:19,200
that uh I can join together in certain
860
00:37:20,940 --> 00:37:21,940
information but I can also exclude them
861
00:37:23,040 --> 00:37:24,040
from certain information in order to
862
00:37:25,380 --> 00:37:26,380
allow for performance by segmenting we
863
00:37:28,500 --> 00:37:29,500
allow communication between the nodes on
864
00:37:30,660 --> 00:37:31,660
each segment to be uninhibited by the
865
00:37:33,780 --> 00:37:34,780
traffic on other segments so I'm not
866
00:37:36,480 --> 00:37:37,480
worried about uh if if computer a wants
867
00:37:40,200 --> 00:37:41,200
to talk to computer C I don't need to
868
00:37:42,540 --> 00:37:43,540
involve all of these guys I can just
869
00:37:45,240 --> 00:37:46,240
allow them to talk directly and so what
870
00:37:47,579 --> 00:37:48,579
it's doing is it's it's basically
871
00:37:48,960 --> 00:37:49,960
keeping a lot of traffic from going over
872
00:37:50,760 --> 00:37:51,760
this line
873
00:37:52,020 --> 00:37:53,020
and therefore we're increasing speed
874
00:37:54,180 --> 00:37:55,180
we're increasing throughput
875
00:37:58,140 --> 00:37:59,140
and we're decreasing the amount of sort
876
00:38:00,359 --> 00:38:01,359
of errors that can occur and we're
877
00:38:01,920 --> 00:38:02,920
segmenting everything out to make it
878
00:38:03,420 --> 00:38:04,420
easier to fix in the future as well
879
00:38:06,000 --> 00:38:07,000
now let's talk about a network model
880
00:38:08,460 --> 00:38:09,460
we've just talked about some Network
881
00:38:10,460 --> 00:38:11,460
categories so now let's talk about the
882
00:38:12,480 --> 00:38:13,480
different models that these are going to
883
00:38:13,680 --> 00:38:14,680
fit into a network model
884
00:38:16,200 --> 00:38:17,200
is a design uh specification if you will
885
00:38:19,560 --> 00:38:20,560
that identifies the transmission path
886
00:38:24,000 --> 00:38:25,000
that nodes on the network are going to
887
00:38:25,920 --> 00:38:26,920
use in order to communicate it basically
888
00:38:28,440 --> 00:38:29,440
determines whether the communication and
889
00:38:31,440 --> 00:38:32,440
the processing
890
00:38:33,300 --> 00:38:34,300
is centralized or distributed
891
00:38:36,900 --> 00:38:37,900
so in a centralized Network this is
892
00:38:40,680 --> 00:38:41,680
where we have our Mainframe
893
00:38:47,040 --> 00:38:48,040
in our terminals
894
00:38:53,160 --> 00:38:54,160
the host computer
895
00:38:56,220 --> 00:38:57,220
this guy the Mainframe provides all of
896
00:38:59,460 --> 00:39:00,460
the processing and all of the network
897
00:39:01,560 --> 00:39:02,560
communication and the users that
898
00:39:04,200 --> 00:39:05,200
interface with the host computer do so
899
00:39:06,599 --> 00:39:07,599
through these Terminals and by using a
900
00:39:09,960 --> 00:39:10,960
terminal emulator that's on the screen
901
00:39:13,859 --> 00:39:14,859
centralized networks are highly
902
00:39:15,839 --> 00:39:16,839
effective but the problem is they can be
903
00:39:18,540 --> 00:39:19,540
a little costly to maintain because this
904
00:39:20,940 --> 00:39:21,940
sucker right here needs to be so
905
00:39:22,500 --> 00:39:23,500
powerful that what if I have instead of
906
00:39:25,140 --> 00:39:26,140
just three computers what if I had a
907
00:39:26,400 --> 00:39:27,400
thousand computers and what if this goes
908
00:39:29,040 --> 00:39:30,040
out well now I'm in major issue I have a
909
00:39:31,859 --> 00:39:32,859
major problem so this is why a lot of
910
00:39:33,839 --> 00:39:34,839
times we use what's called a client
911
00:39:35,460 --> 00:39:36,460
server model
912
00:39:38,820 --> 00:39:39,820
the client server model it
913
00:39:41,880 --> 00:39:42,880
in the client server model the server is
914
00:39:44,339 --> 00:39:45,339
responsible
915
00:39:46,200 --> 00:39:47,200
the server right here is responsible for
916
00:39:48,599 --> 00:39:49,599
providing services like file sharing and
917
00:39:52,500 --> 00:39:53,500
printer sharing and authentication
918
00:39:54,240 --> 00:39:55,240
services and data storage and management
919
00:39:57,020 --> 00:39:58,020
to these clients the main difference
920
00:40:00,420 --> 00:40:01,420
between the centralized and the client
921
00:40:03,180 --> 00:40:04,180
server model is that in this client
922
00:40:05,700 --> 00:40:06,700
server Network the processing and the
923
00:40:08,820 --> 00:40:09,820
resources can be allocated wherever they
924
00:40:11,640 --> 00:40:12,640
are needed including on the client and
925
00:40:14,640 --> 00:40:15,640
they can also be distributed whenever
926
00:40:16,320 --> 00:40:17,320
necessary
927
00:40:17,480 --> 00:40:18,480
and the end
928
00:40:20,579 --> 00:40:21,579
nodes These Guys these clients can still
929
00:40:24,480 --> 00:40:25,480
perform their own processing and end
930
00:40:27,060 --> 00:40:28,060
user tasks without having to constantly
931
00:40:29,040 --> 00:40:30,040
talk over to the server so if I need a
932
00:40:32,040 --> 00:40:33,040
file for instance I can get that file do
933
00:40:34,800 --> 00:40:35,800
the work on my computer and then I can
934
00:40:36,900 --> 00:40:37,900
save it back to the server whereas here
935
00:40:39,240 --> 00:40:40,240
on the centralized Mainframe terminal
936
00:40:41,339 --> 00:40:42,339
setup all the work is actually done on
937
00:40:44,460 --> 00:40:45,460
this major huge computer and here in the
938
00:40:47,640 --> 00:40:48,640
terminal we're just sort of having a
939
00:40:49,380 --> 00:40:50,380
portal to see what's going on now both
940
00:40:52,440 --> 00:40:53,440
of these are different from what we call
941
00:40:55,140 --> 00:40:56,140
a peer-to-peer Network we talked about
942
00:40:57,599 --> 00:40:58,599
appear in the previous module but a
943
00:41:00,119 --> 00:41:01,119
peer-to-peer Network which you might
944
00:41:01,380 --> 00:41:02,380
also see as P2P or PTP
945
00:41:07,619 --> 00:41:08,619
uh is a network in which each node on
946
00:41:12,000 --> 00:41:13,000
the network is responsible for its own
947
00:41:14,460 --> 00:41:15,460
Computing its own management its own
948
00:41:16,440 --> 00:41:17,440
security its own storage its own
949
00:41:19,260 --> 00:41:20,260
resource sharing like printers it's
950
00:41:22,020 --> 00:41:23,020
completely decentralized and it's
951
00:41:24,359 --> 00:41:25,359
commonly referred to as a work group
952
00:41:27,480 --> 00:41:28,480
now this is sort of like if we were
953
00:41:29,400 --> 00:41:30,400
going to make a reference to a political
954
00:41:32,160 --> 00:41:33,160
metaphor this would be like communism
955
00:41:35,099 --> 00:41:36,099
everyone works together equally and
956
00:41:38,520 --> 00:41:39,520
everyone is responsible for their own
957
00:41:41,099 --> 00:41:42,099
thing and then they can share that with
958
00:41:43,260 --> 00:41:44,260
everyone else whereas in a client server
959
00:41:46,680 --> 00:41:47,680
sort of uh
960
00:41:49,619 --> 00:41:50,619
model we're dealing with say a democracy
961
00:41:53,640 --> 00:41:54,640
in which you have a president or prime
962
00:41:55,320 --> 00:41:56,320
minister someone who's going to make a
963
00:41:57,300 --> 00:41:58,300
lot of the decisions but you are still
964
00:41:59,099 --> 00:42:00,099
at Liberty to exercise a lot of your own
965
00:42:01,260 --> 00:42:02,260
stuff and that's very different from
966
00:42:03,660 --> 00:42:04,660
say a terminal Mainframe which is would
967
00:42:07,619 --> 00:42:08,619
be equivalent to like a monarchy a
968
00:42:09,359 --> 00:42:10,359
really strict here I should say
969
00:42:10,940 --> 00:42:11,940
tyrannical monarchy in which everything
970
00:42:13,560 --> 00:42:14,560
is decided for you and you make no
971
00:42:15,839 --> 00:42:16,839
decisions on your own so one of the
972
00:42:19,020 --> 00:42:20,020
problem with work groups is that user
973
00:42:22,500 --> 00:42:23,500
accounts need to be replicated onto each
974
00:42:24,599 --> 00:42:25,599
node so that if I want to get access to
975
00:42:27,060 --> 00:42:28,060
this computer and I usually work on
976
00:42:29,160 --> 00:42:30,160
computer y all of my username password
977
00:42:31,980 --> 00:42:32,980
everything is going to be on there and
978
00:42:33,839 --> 00:42:34,839
if it's not done if I don't sort of copy
979
00:42:36,180 --> 00:42:37,180
everything over there's no way I can
980
00:42:37,320 --> 00:42:38,320
gain access so this is the problem with
981
00:42:39,599 --> 00:42:40,599
this model is each person's their own
982
00:42:41,280 --> 00:42:42,280
but if x has wheat and I have corn
983
00:42:44,599 --> 00:42:45,599
there's sort of no sharing that's
984
00:42:46,920 --> 00:42:47,920
automatically set up we have to create
985
00:42:49,140 --> 00:42:50,140
our own sort of share and then if
986
00:42:50,700 --> 00:42:51,700
someone else says something I have to
987
00:42:51,900 --> 00:42:52,900
share with them and so on and so forth
988
00:42:53,579 --> 00:42:54,579
now we might sometimes mix these
989
00:42:55,800 --> 00:42:56,800
together into what's called a mixed mode
990
00:42:57,660 --> 00:42:58,660
Network and that's just like it sounds
991
00:42:59,880 --> 00:43:00,880
it mixes aspects of two or more of the
992
00:43:02,280 --> 00:43:03,280
different network models an example
993
00:43:04,920 --> 00:43:05,920
might be a work group of computers
994
00:43:07,440 --> 00:43:08,440
connected together via some sort of
995
00:43:09,599 --> 00:43:10,599
short range Wireless while allowing
996
00:43:12,720 --> 00:43:13,720
those computers to connect to a
997
00:43:14,640 --> 00:43:15,640
Mainframe computer and using terminal
998
00:43:16,859 --> 00:43:17,859
emulation
999
00:43:17,940 --> 00:43:18,940
so alternative we might have a work
1000
00:43:20,520 --> 00:43:21,520
group and then a centralized server Etc
1001
00:43:22,380 --> 00:43:23,380
so we see we can see mixed mode networks
1002
00:43:24,900 --> 00:43:25,900
they're usually uh not as popular in
1003
00:43:27,599 --> 00:43:28,599
huge Enterprises because of the lack of
1004
00:43:29,460 --> 00:43:30,460
control
1005
00:43:30,960 --> 00:43:31,960
um except in certain specific instances
1006
00:43:33,119 --> 00:43:34,119
uh but we do see them and it's important
1007
00:43:35,700 --> 00:43:36,700
to know that just like in anything we
1008
00:43:37,619 --> 00:43:38,619
can mix and match
1009
00:43:39,599 --> 00:43:40,599
to however we want the the network to
1010
00:43:41,640 --> 00:43:42,640
work all right so now just to recap what
1011
00:43:44,099 --> 00:43:45,099
we've talked about we can now describe
1012
00:43:46,740 --> 00:43:47,740
and Define the characteristics of a lan
1013
00:43:49,260 --> 00:43:50,260
or a local area network as well as a Wan
1014
00:43:52,680 --> 00:43:53,680
or a wide area network and we also
1015
00:43:54,780 --> 00:43:55,780
talked about several of the uh different
1016
00:43:57,900 --> 00:43:58,900
types of lands or in some cases lands
1017
00:44:01,400 --> 00:44:02,400
including a can or campus area network a
1018
00:44:06,540 --> 00:44:07,540
man or municipal or metropolitan area
1019
00:44:09,599 --> 00:44:10,599
network a pan or personal area network
1020
00:44:12,720 --> 00:44:13,720
which is where the computers connect
1021
00:44:14,220 --> 00:44:15,220
directly to one another and then we
1022
00:44:16,260 --> 00:44:17,260
looked at a gan or a global area network
1023
00:44:18,900 --> 00:44:19,900
and then we also talked about en or an
1024
00:44:21,960 --> 00:44:22,960
Enterprise Network okay so these are all
1025
00:44:25,079 --> 00:44:26,079
uh different
1026
00:44:27,859 --> 00:44:28,859
acronyms that you need to learn for the
1027
00:44:30,180 --> 00:44:31,180
exam we also talked about uh an internet
1028
00:44:33,800 --> 00:44:34,800
intranet an Extranet remember the
1029
00:44:36,119 --> 00:44:37,119
internet is that World Wide Web right
1030
00:44:39,119 --> 00:44:40,119
the cloud the intranet is sort of using
1031
00:44:42,540 --> 00:44:43,540
this Cloud but in your company
1032
00:44:45,720 --> 00:44:46,720
and keeping it private that's my little
1033
00:44:47,700 --> 00:44:48,700
building and the Extranet is allowing
1034
00:44:51,180 --> 00:44:52,180
access
1035
00:44:53,099 --> 00:44:54,099
of your company private intranet to
1036
00:44:56,520 --> 00:44:57,520
perhaps
1037
00:44:57,780 --> 00:44:58,780
certain individuals from outside so it's
1038
00:45:00,900 --> 00:45:01,900
just a little bit of that
1039
00:45:02,520 --> 00:45:03,520
we also talked about a centralized
1040
00:45:04,380 --> 00:45:05,380
Network which is mostly
1041
00:45:07,220 --> 00:45:08,220
what we talk about when we deal with
1042
00:45:09,720 --> 00:45:10,720
terminals
1043
00:45:11,339 --> 00:45:12,339
and mainframes
1044
00:45:13,980 --> 00:45:14,980
and we'll sort of deal with this a
1045
00:45:16,020 --> 00:45:17,020
little bit too when we get into uh
1046
00:45:18,720 --> 00:45:19,720
virtualization when we talked about Thin
1047
00:45:20,700 --> 00:45:21,700
and Thick clients this is the idea of a
1048
00:45:22,560 --> 00:45:23,560
thin client on a network with a
1049
00:45:25,740 --> 00:45:26,740
a server of some sort or a
1050
00:45:28,579 --> 00:45:29,579
Mainframe I should say that is going to
1051
00:45:31,079 --> 00:45:32,079
do all the processing for it we also
1052
00:45:33,180 --> 00:45:34,180
looked at a client server Network which
1053
00:45:36,060 --> 00:45:37,060
is the majority of the types of networks
1054
00:45:37,859 --> 00:45:38,859
we see in Enterprise settings and a
1055
00:45:40,079 --> 00:45:41,079
peer-to-peer Network which we also call
1056
00:45:42,660 --> 00:45:43,660
a work group network in which every peer
1057
00:45:46,560 --> 00:45:47,560
is both a client and a server
1058
00:45:49,079 --> 00:45:50,079
responsible for its own
1059
00:45:51,900 --> 00:45:52,900
um
1060
00:45:52,680 --> 00:45:53,680
its own resources and so on I think we
1061
00:45:55,200 --> 00:45:56,200
use the metaphor that this might be like
1062
00:45:57,300 --> 00:45:58,300
uh
1063
00:45:59,280 --> 00:46:00,280
communism this might be like a client
1064
00:46:02,819 --> 00:46:03,819
server might be like sort of uh
1065
00:46:05,960 --> 00:46:06,960
democracy of some sort or a republic of
1066
00:46:09,420 --> 00:46:10,420
some sort and a centralized Network
1067
00:46:12,660 --> 00:46:13,660
would be more like I guess I should say
1068
00:46:16,200 --> 00:46:17,200
a democracy that is also republic since
1069
00:46:19,980 --> 00:46:20,980
um we do have officials and there's
1070
00:46:22,200 --> 00:46:23,200
someone above us right but a prime
1071
00:46:24,480 --> 00:46:25,480
minister a president sort of system and
1072
00:46:26,579 --> 00:46:27,579
then a centralized Network would be like
1073
00:46:28,260 --> 00:46:29,260
a tyranny
1074
00:46:29,819 --> 00:46:30,819
or a tyrannical Monarch I should say and
1075
00:46:33,060 --> 00:46:34,060
then we have a mixed mode Network which
1076
00:46:34,800 --> 00:46:35,800
is sort of a combination of uh the above
1077
00:46:38,579 --> 00:46:39,579
great
1078
00:46:40,079 --> 00:46:41,079
so we've talked now about uh some of the
1079
00:46:43,319 --> 00:46:44,319
basic terminology we've talked about the
1080
00:46:45,720 --> 00:46:46,720
models we've also talked about the
1081
00:46:48,119 --> 00:46:49,119
different categories so let's finish up
1082
00:46:51,119 --> 00:46:52,119
this basic Network fundamentals area by
1083
00:46:53,280 --> 00:46:54,280
talking about what are what are called
1084
00:46:54,720 --> 00:46:55,720
topologies how the networks are
1085
00:46:56,700 --> 00:46:57,700
physically set up and how they logically
1086
00:46:58,560 --> 00:46:59,560
communicate with one another
1087
00:47:03,390 --> 00:47:04,390
[Music]
1088
00:47:11,960 --> 00:47:12,960
thank you
1089
00:47:28,500 --> 00:47:29,500
Network fundamentals Network topologies
1090
00:47:33,180 --> 00:47:34,180
so now we're going to explain Network
1091
00:47:35,240 --> 00:47:36,240
topologies or uh the network layout both
1092
00:47:39,359 --> 00:47:40,359
physical and logical physical being how
1093
00:47:42,060 --> 00:47:43,060
it's physically connected and logical
1094
00:47:44,220 --> 00:47:45,220
being how the information is
1095
00:47:45,900 --> 00:47:46,900
communicated over that physical Network
1096
00:47:47,579 --> 00:47:48,579
and we're going to define the different
1097
00:47:49,260 --> 00:47:50,260
standard topologies that are in use for
1098
00:47:51,420 --> 00:47:52,420
today
1099
00:47:52,380 --> 00:47:53,380
so uh we're first going to Define
1100
00:47:54,660 --> 00:47:55,660
topology in general
1101
00:47:56,640 --> 00:47:57,640
then we're going to talk about physical
1102
00:47:58,260 --> 00:47:59,260
topology followed by logical topology
1103
00:48:02,160 --> 00:48:03,160
we're then going to explain a few of the
1104
00:48:04,020 --> 00:48:05,020
different types of topologies you need
1105
00:48:05,520 --> 00:48:06,520
to be familiar with for the exam
1106
00:48:06,900 --> 00:48:07,900
including a bus topology
1107
00:48:09,839 --> 00:48:10,839
star topology
1108
00:48:11,819 --> 00:48:12,819
a ring topology
1109
00:48:14,280 --> 00:48:15,280
a tree topology
1110
00:48:16,619 --> 00:48:17,619
and a mesh topology we're also going to
1111
00:48:19,200 --> 00:48:20,200
talk about a mixture of all of these
1112
00:48:21,180 --> 00:48:22,180
topologies that is called
1113
00:48:24,060 --> 00:48:25,060
a hybrid topology
1114
00:48:26,400 --> 00:48:27,400
these are the things you really want to
1115
00:48:27,780 --> 00:48:28,780
pay attention to these different names
1116
00:48:29,220 --> 00:48:30,220
and the names correspond directly to how
1117
00:48:32,280 --> 00:48:33,280
everything is set up so I don't think
1118
00:48:33,660 --> 00:48:34,660
it'll be too hard for you to remember or
1119
00:48:36,720 --> 00:48:37,720
to memorize
1120
00:48:40,020 --> 00:48:41,020
so as administrators regardless of the
1121
00:48:43,440 --> 00:48:44,440
specific role we're in we have to have a
1122
00:48:45,420 --> 00:48:46,420
complete understanding of the layout or
1123
00:48:47,579 --> 00:48:48,579
the arrangement of the network this
1124
00:48:50,099 --> 00:48:51,099
allows us to effectively design manage
1125
00:48:52,920 --> 00:48:53,920
and troubleshoot the networks for
1126
00:48:55,460 --> 00:48:56,460
performance and scalability a
1127
00:48:58,319 --> 00:48:59,319
scalability by the way I'm just going to
1128
00:49:00,660 --> 00:49:01,660
write that out here
1129
00:49:02,579 --> 00:49:03,579
because it is a term we'll see come up
1130
00:49:04,380 --> 00:49:05,380
over and over again is
1131
00:49:07,200 --> 00:49:08,200
um
1132
00:49:08,339 --> 00:49:09,339
how you can either make the network
1133
00:49:10,560 --> 00:49:11,560
larger or smaller depending on needs
1134
00:49:14,099 --> 00:49:15,099
certain topologies have characteristics
1135
00:49:17,099 --> 00:49:18,099
that allow us to have more efficient
1136
00:49:19,500 --> 00:49:20,500
communication while other topologies
1137
00:49:21,660 --> 00:49:22,660
focus more on immediate or faster
1138
00:49:23,940 --> 00:49:24,940
communication between certain devices so
1139
00:49:27,119 --> 00:49:28,119
understanding the topology of the
1140
00:49:29,760 --> 00:49:30,760
network allows us administrators to
1141
00:49:32,460 --> 00:49:33,460
troubleshoot the problems we're having
1142
00:49:34,319 --> 00:49:35,319
and then Implement Solutions easier and
1143
00:49:37,980 --> 00:49:38,980
more efficiently
1144
00:49:39,780 --> 00:49:40,780
so there are two types of topologies in
1145
00:49:43,140 --> 00:49:44,140
general and then there are specific
1146
00:49:44,760 --> 00:49:45,760
names for each of those topologies but
1147
00:49:46,560 --> 00:49:47,560
the two types are physical and logical
1148
00:49:48,839 --> 00:49:49,839
so uh let's take a look at the
1149
00:49:51,000 --> 00:49:52,000
characteristics that define a physical
1150
00:49:52,800 --> 00:49:53,800
topology and a logical topology
1151
00:49:58,200 --> 00:49:59,200
Google topology is the actual physical
1152
00:50:00,780 --> 00:50:01,780
layout of the devices so this is like
1153
00:50:04,560 --> 00:50:05,560
looking at the blueprint of our Network
1154
00:50:06,900 --> 00:50:07,900
this tells us how the devices are
1155
00:50:09,300 --> 00:50:10,300
actually physically connected to one
1156
00:50:11,940 --> 00:50:12,940
another it's also the shape of the
1157
00:50:14,099 --> 00:50:15,099
network and it gives us a sort of
1158
00:50:15,480 --> 00:50:16,480
picture to represent the layout or the
1159
00:50:19,020 --> 00:50:20,020
blueprint the physical topology ensures
1160
00:50:22,920 --> 00:50:23,920
that we administrators know and
1161
00:50:25,140 --> 00:50:26,140
understand how the physical media like
1162
00:50:27,780 --> 00:50:28,780
cables connect the devices to one
1163
00:50:30,180 --> 00:50:31,180
another
1164
00:50:31,319 --> 00:50:32,319
so a logical topology on the other hand
1165
00:50:34,680 --> 00:50:35,680
describes the how in other words it's
1166
00:50:37,800 --> 00:50:38,800
the pathway that data takes regardless
1167
00:50:40,800 --> 00:50:41,800
of how the network is physically laid
1168
00:50:43,319 --> 00:50:44,319
out this is how the data is actually
1169
00:50:46,200 --> 00:50:47,200
communicated over the physical
1170
00:50:49,079 --> 00:50:50,079
so the logical topology allows
1171
00:50:51,180 --> 00:50:52,180
administrators to troubleshoot and
1172
00:50:54,720 --> 00:50:55,720
fix the problems we're having with
1173
00:50:57,119 --> 00:50:58,119
communication between devices by
1174
00:51:00,180 --> 00:51:01,180
understanding the path that the data is
1175
00:51:03,359 --> 00:51:04,359
actually taking and we'll see some
1176
00:51:05,400 --> 00:51:06,400
pictures of this in just a second so
1177
00:51:07,020 --> 00:51:08,020
that will make this all a lot more clear
1178
00:51:09,440 --> 00:51:10,440
in a lot of cases the logical topology
1179
00:51:13,859 --> 00:51:14,859
could be very different from the
1180
00:51:15,660 --> 00:51:16,660
physical topology
1181
00:51:17,099 --> 00:51:18,099
so only because one logical topology is
1182
00:51:19,559 --> 00:51:20,559
for instance the star doesn't mean the
1183
00:51:21,119 --> 00:51:22,119
physical topology is also going to be a
1184
00:51:22,680 --> 00:51:23,680
star you can have a physical star and a
1185
00:51:25,740 --> 00:51:26,740
logical bus so that's why it's important
1186
00:51:27,780 --> 00:51:28,780
we understand but the difference between
1187
00:51:29,280 --> 00:51:30,280
logical and physical
1188
00:51:30,780 --> 00:51:31,780
so now that we've defined the difference
1189
00:51:32,400 --> 00:51:33,400
in a physical and a logical topology I
1190
00:51:34,859 --> 00:51:35,859
want to look at some of the different
1191
00:51:36,119 --> 00:51:37,119
connection methods that we use in these
1192
00:51:38,579 --> 00:51:39,579
topologies in the specific layouts both
1193
00:51:40,740 --> 00:51:41,740
for physical and logical uh but first
1194
00:51:43,559 --> 00:51:44,559
let's talk about how these things
1195
00:51:45,180 --> 00:51:46,180
connect because that's going to keep
1196
00:51:46,740 --> 00:51:47,740
coming back up
1197
00:51:48,660 --> 00:51:49,660
so the first type we have is called a
1198
00:51:51,300 --> 00:51:52,300
point-to-point connection this is a
1199
00:51:54,420 --> 00:51:55,420
direct connection between two nodes on
1200
00:51:57,359 --> 00:51:58,359
the network and remember when we're
1201
00:51:58,859 --> 00:51:59,859
talking nodes that could be two
1202
00:52:01,319 --> 00:52:02,319
computers
1203
00:52:02,960 --> 00:52:03,960
uh printers
1204
00:52:08,880 --> 00:52:09,880
Etc and remember we had endpoint nodes
1205
00:52:11,099 --> 00:52:12,099
and then we had redistribution nodes
1206
00:52:14,400 --> 00:52:15,400
so this these can either by the way be
1207
00:52:17,040 --> 00:52:18,040
wired or Wireless so an example of a
1208
00:52:20,099 --> 00:52:21,099
wireless point-to-point connection would
1209
00:52:21,720 --> 00:52:22,720
be for instance two nodes using an
1210
00:52:24,359 --> 00:52:25,359
infrared connection to communicate with
1211
00:52:26,819 --> 00:52:27,819
one another like your TV and your remote
1212
00:52:28,800 --> 00:52:29,800
control a wired point-to-point
1213
00:52:31,380 --> 00:52:32,380
connection on the other hand would be
1214
00:52:33,480 --> 00:52:34,480
two computers with network interface
1215
00:52:36,300 --> 00:52:37,300
cards or nics remember that term
1216
00:52:39,480 --> 00:52:40,480
okay connected directly together with
1217
00:52:42,300 --> 00:52:43,300
what's called a crossover cable so
1218
00:52:45,240 --> 00:52:46,240
there's nothing in between them right
1219
00:52:46,619 --> 00:52:47,619
they're connected directly to one
1220
00:52:47,940 --> 00:52:48,940
another using cables this might also be
1221
00:52:50,460 --> 00:52:51,460
the same thing we do if we connected two
1222
00:52:51,900 --> 00:52:52,900
computers together somehow using USB uh
1223
00:52:55,740 --> 00:52:56,740
cables although that's not really going
1224
00:52:57,540 --> 00:52:58,540
to happen very often in a network
1225
00:52:59,040 --> 00:53:00,040
setting the next type we have is called
1226
00:53:01,200 --> 00:53:02,200
a multi-point connection now as the name
1227
00:53:03,480 --> 00:53:04,480
implies we had point to point that's
1228
00:53:05,880 --> 00:53:06,880
like one to one
1229
00:53:08,280 --> 00:53:09,280
and then we have multi-point connections
1230
00:53:12,660 --> 00:53:13,660
which means that there are connections
1231
00:53:14,579 --> 00:53:15,579
between multiple nodes so there are two
1232
00:53:17,460 --> 00:53:18,460
or more endpoints connected together by
1233
00:53:20,940 --> 00:53:21,940
each multi-point Connection in other
1234
00:53:23,040 --> 00:53:24,040
words all transmissions are not private
1235
00:53:24,900 --> 00:53:25,900
because every node on the network can
1236
00:53:27,240 --> 00:53:28,240
detect the signal being transmitted
1237
00:53:29,460 --> 00:53:30,460
now there's also something called a
1238
00:53:31,440 --> 00:53:32,440
radiated connection and as the name
1239
00:53:33,720 --> 00:53:34,720
implies radiated this is specifically a
1240
00:53:37,079 --> 00:53:38,079
wireless connection so data is
1241
00:53:40,200 --> 00:53:41,200
transmitted wirelessly between devices
1242
00:53:42,359 --> 00:53:43,359
it's also by the way called a broadcast
1243
00:53:48,359 --> 00:53:49,359
connection uh although broadcast also
1244
00:53:51,359 --> 00:53:52,359
means something different as we will see
1245
00:53:52,859 --> 00:53:53,859
in just a minute
1246
00:53:54,059 --> 00:53:55,059
so some radiated connections would be
1247
00:53:56,640 --> 00:53:57,640
like Wi-Fi or wireless LAN and in some
1248
00:54:00,059 --> 00:54:01,059
cases even an infrared like your um a
1249
00:54:03,240 --> 00:54:04,240
remote control but the reason that
1250
00:54:04,559 --> 00:54:05,559
that's a point to point is it uh
1251
00:54:06,540 --> 00:54:07,540
infrared requires direct line of sight
1252
00:54:13,319 --> 00:54:14,319
whereas radiated connections that can be
1253
00:54:16,260 --> 00:54:17,260
either point to point or multi-point so
1254
00:54:20,400 --> 00:54:21,400
it sort of is uh it sort of involves all
1255
00:54:23,460 --> 00:54:24,460
of these different ones
1256
00:54:26,339 --> 00:54:27,339
all right now let's talk some about some
1257
00:54:27,960 --> 00:54:28,960
of the specific uh topologies the first
1258
00:54:30,359 --> 00:54:31,359
one I want to talk about is a physical
1259
00:54:31,619 --> 00:54:32,619
bus topology not a logical bust apology
1260
00:54:35,160 --> 00:54:36,160
okay so again this is the physical how
1261
00:54:37,020 --> 00:54:38,020
things are physically connected and what
1262
00:54:39,599 --> 00:54:40,599
this means is each node is arranged as
1263
00:54:42,059 --> 00:54:43,059
you can tell in a line so this is like
1264
00:54:44,880 --> 00:54:45,880
seats on a school bus everyone on the
1265
00:54:47,579 --> 00:54:48,579
bus can hear the transmission but the
1266
00:54:50,280 --> 00:54:51,280
message is only received by one specific
1267
00:54:53,339 --> 00:54:54,339
recipient so a bust topology is an
1268
00:54:56,700 --> 00:54:57,700
example of a multi-point connection
1269
00:54:58,559 --> 00:54:59,559
right because we have
1270
00:55:02,480 --> 00:55:03,480
it goes to all these different points
1271
00:55:04,859 --> 00:55:05,859
there are many points connected to it if
1272
00:55:07,079 --> 00:55:08,079
the message is for everyone on the bus
1273
00:55:09,660 --> 00:55:10,660
so I'm meaning I want to send this
1274
00:55:11,579 --> 00:55:12,579
message out to everyone that would be
1275
00:55:13,559 --> 00:55:14,559
called a broadcast connection broadcast
1276
00:55:16,079 --> 00:55:17,079
meaning it is intended and sent to every
1277
00:55:20,040 --> 00:55:21,040
single person on the bus or every node
1278
00:55:22,619 --> 00:55:23,619
uh on the network
1279
00:55:24,660 --> 00:55:25,660
If the message on the other hand is
1280
00:55:26,280 --> 00:55:27,280
meant to just go to one person or one
1281
00:55:28,980 --> 00:55:29,980
node we're going to call that unicast
1282
00:55:32,720 --> 00:55:33,720
uh finally if it's intended to go to
1283
00:55:35,760 --> 00:55:36,760
more than one recipient but not all of
1284
00:55:37,440 --> 00:55:38,440
them then we're looking at a multicast
1285
00:55:39,240 --> 00:55:40,240
Okay so unicast
1286
00:55:43,140 --> 00:55:44,140
as the name implies
1287
00:55:45,359 --> 00:55:46,359
means
1288
00:55:48,599 --> 00:55:49,599
one recipient
1289
00:55:51,780 --> 00:55:52,780
multicast
1290
00:55:56,460 --> 00:55:57,460
is two
1291
00:56:00,180 --> 00:56:01,180
or more
1292
00:56:04,079 --> 00:56:05,079
recipients
1293
00:56:05,940 --> 00:56:06,940
and then I'm just going to write this up
1294
00:56:08,099 --> 00:56:09,099
here broadcast as the name implies like
1295
00:56:11,220 --> 00:56:12,220
a television broadcast it goes to all
1296
00:56:14,640 --> 00:56:15,640
recipients on the network
1297
00:56:16,859 --> 00:56:17,859
it's important to understand the
1298
00:56:18,300 --> 00:56:19,300
difference in these types of messages we
1299
00:56:20,280 --> 00:56:21,280
have broadcast messages go out to
1300
00:56:21,720 --> 00:56:22,720
everyone unicast messages go out to one
1301
00:56:24,059 --> 00:56:25,059
recipient multicast to two or more but
1302
00:56:26,700 --> 00:56:27,700
different from broadcast because it's
1303
00:56:28,140 --> 00:56:29,140
not going to everyone or all of them the
1304
00:56:31,800 --> 00:56:32,800
way multicast works is that only uh the
1305
00:56:36,119 --> 00:56:37,119
stations or the nodes that have
1306
00:56:37,680 --> 00:56:38,680
subscribed to a message will receive it
1307
00:56:39,960 --> 00:56:40,960
so we could if we're using a TV sort of
1308
00:56:42,420 --> 00:56:43,420
example unicast would be like if you
1309
00:56:44,339 --> 00:56:45,339
have a direct line to your sort of
1310
00:56:46,980 --> 00:56:47,980
television provider multicast would be
1311
00:56:48,960 --> 00:56:49,960
like HP only those subscribing to the
1312
00:56:51,780 --> 00:56:52,780
specific uh cable network get access to
1313
00:56:55,140 --> 00:56:56,140
it broadcast is sort of any it's in the
1314
00:56:57,300 --> 00:56:58,300
air anyone can get it right so on a bust
1315
00:57:00,240 --> 00:57:01,240
apology like we're looking at right now
1316
00:57:02,160 --> 00:57:03,160
when the data is transmitted the signal
1317
00:57:05,339 --> 00:57:06,339
will bounce or reflect off of
1318
00:57:08,099 --> 00:57:09,099
the ends and so it's important
1319
00:57:11,280 --> 00:57:12,280
uh that when the signal bounces it's
1320
00:57:14,220 --> 00:57:15,220
gonna interrupt the transmission if
1321
00:57:16,260 --> 00:57:17,260
there's nothing there to stop that
1322
00:57:17,520 --> 00:57:18,520
bounce from occurring so to keep this
1323
00:57:19,559 --> 00:57:20,559
from happening we generally have
1324
00:57:20,940 --> 00:57:21,940
something called a terminator and it's
1325
00:57:23,099 --> 00:57:24,099
generally around 50 ohms I would
1326
00:57:25,020 --> 00:57:26,020
remember that for the exam because I do
1327
00:57:26,819 --> 00:57:27,819
see that pop up and what this does is it
1328
00:57:29,220 --> 00:57:30,220
really grounds the bus transmission or
1329
00:57:32,099 --> 00:57:33,099
the bus connections to reduce uh and it
1330
00:57:35,400 --> 00:57:36,400
reduces static electricity to keep this
1331
00:57:37,859 --> 00:57:38,859
Bounce from occurring that bounce occurs
1332
00:57:39,960 --> 00:57:40,960
then we're having all sorts of problems
1333
00:57:42,000 --> 00:57:43,000
start to occur in our Network now uh if
1334
00:57:45,420 --> 00:57:46,420
the way that these nodes are connected
1335
00:57:47,160 --> 00:57:48,160
as you can see are by these T connectors
1336
00:57:49,920 --> 00:57:50,920
and the reason they're called T
1337
00:57:50,880 --> 00:57:51,880
connectors is because they look like an
1338
00:57:52,319 --> 00:57:53,319
upside down t
1339
00:57:54,059 --> 00:57:55,059
now the downside to using a bus
1340
00:57:56,579 --> 00:57:57,579
connection are obviously these
1341
00:57:57,720 --> 00:57:58,720
terminators
1342
00:57:58,980 --> 00:57:59,980
and uh it's a little frustrating to sort
1343
00:58:02,460 --> 00:58:03,460
of connect these up but the upside to
1344
00:58:04,800 --> 00:58:05,800
using a bus technology uh topology
1345
00:58:07,260 --> 00:58:08,260
rather is that it's inexpensive and it's
1346
00:58:09,599 --> 00:58:10,599
relatively easy to implement
1347
00:58:13,680 --> 00:58:14,680
now this is different from a physical
1348
00:58:15,119 --> 00:58:16,119
star topology as you can see now instead
1349
00:58:17,460 --> 00:58:18,460
of a line everything is connected to
1350
00:58:19,440 --> 00:58:20,440
every other device using a central
1351
00:58:21,540 --> 00:58:22,540
connection device such as a switch
1352
00:58:25,980 --> 00:58:26,980
or a hub
1353
00:58:28,380 --> 00:58:29,380
in a physical start topology where a
1354
00:58:30,960 --> 00:58:31,960
switch is used what happens
1355
00:58:33,960 --> 00:58:34,960
is the node that's transmitting the data
1356
00:58:36,240 --> 00:58:37,240
to another node uh the switch actually
1357
00:58:38,940 --> 00:58:39,940
will
1358
00:58:40,559 --> 00:58:41,559
determine where that information needs
1359
00:58:42,780 --> 00:58:43,780
to go and send it only to the
1360
00:58:46,260 --> 00:58:47,260
node that is the intended recipient like
1361
00:58:49,140 --> 00:58:50,140
a unicast right
1362
00:58:51,960 --> 00:58:52,960
on the other hand a hub
1363
00:58:54,900 --> 00:58:55,900
is going to send the data out
1364
00:58:57,839 --> 00:58:58,839
to everyone and what's more like a
1365
00:59:00,480 --> 00:59:01,480
broadcast connection
1366
00:59:02,220 --> 00:59:03,220
now the uh and we'll talk more about
1367
00:59:05,160 --> 00:59:06,160
hubs and switches a little bit later
1368
00:59:06,960 --> 00:59:07,960
when we get to devices
1369
00:59:09,720 --> 00:59:10,720
the physical start topology it's very
1370
00:59:12,299 --> 00:59:13,299
common today and it's uh easy to
1371
00:59:15,660 --> 00:59:16,660
implement and maintain and it's much
1372
00:59:17,880 --> 00:59:18,880
more reliable than bust apologies
1373
00:59:19,500 --> 00:59:20,500
because if one node fails or one
1374
00:59:23,160 --> 00:59:24,160
connection to a node fails uh for
1375
00:59:25,440 --> 00:59:26,440
instance this one
1376
00:59:26,760 --> 00:59:27,760
then the rest of the network isn't
1377
00:59:28,319 --> 00:59:29,319
affected and a sort of client server
1378
00:59:30,960 --> 00:59:31,960
Arrangement each node is inherently not
1379
00:59:34,920 --> 00:59:35,920
aware of all the other nodes on the
1380
00:59:36,780 --> 00:59:37,780
network because the node only has a
1381
00:59:39,720 --> 00:59:40,720
connection
1382
00:59:42,180 --> 00:59:43,180
to this Central sort of host now the
1383
00:59:44,819 --> 00:59:45,819
negative aspect of this physical start
1384
00:59:46,380 --> 00:59:47,380
topology is we have what's called a
1385
00:59:48,780 --> 00:59:49,780
single point of failure here in this
1386
00:59:51,059 --> 00:59:52,059
connectivity device and if that fails
1387
00:59:53,160 --> 00:59:54,160
all of the other devices won't be able
1388
00:59:55,200 --> 00:59:56,200
to communicate so the benefit is now not
1389
00:59:57,599 --> 00:59:58,599
everyone has to get the message and it's
1390
00:59:59,640 --> 01:00:00,640
easier to uh it's sort of really cheap
1391
01:00:01,680 --> 01:00:02,680
and easy to implement it's also the most
1392
01:00:03,180 --> 01:00:04,180
popular because of any of these
1393
01:00:05,040 --> 01:00:06,040
connections go down I don't lose
1394
01:00:06,240 --> 01:00:07,240
connection to the whole thing unlike the
1395
01:00:08,220 --> 01:00:09,220
bus where if one of those connections
1396
01:00:09,480 --> 01:00:10,480
goes down obviously the connection can't
1397
01:00:11,579 --> 01:00:12,579
continue but the downside is that I now
1398
01:00:14,160 --> 01:00:15,160
have a single point of failure in this
1399
01:00:15,540 --> 01:00:16,540
Central device
1400
01:00:19,319 --> 01:00:20,319
now in a physical ring topology each
1401
01:00:22,799 --> 01:00:23,799
node is connected directly to its
1402
01:00:24,720 --> 01:00:25,720
upstream and its Downstream neighbors so
1403
01:00:28,319 --> 01:00:29,319
if we're looking at this device we'll
1404
01:00:29,760 --> 01:00:30,760
call it a those are the upstream and
1405
01:00:31,920 --> 01:00:32,920
downstream neighbors it's much like
1406
01:00:33,540 --> 01:00:34,540
water in an actual uh like River or
1407
01:00:36,059 --> 01:00:37,059
stream the flow of data in the physical
1408
01:00:38,880 --> 01:00:39,880
ring topology is unidirectional meaning
1409
01:00:42,119 --> 01:00:43,119
it only goes in One Direction
1410
01:00:45,480 --> 01:00:46,480
so the terms upstream and downstream are
1411
01:00:49,260 --> 01:00:50,260
only used in the ring topology
1412
01:00:52,559 --> 01:00:53,559
now here's the positive in using the
1413
01:00:54,299 --> 01:00:55,299
ring topology because data is received
1414
01:00:57,059 --> 01:00:58,059
and then re-transmitted
1415
01:01:00,780 --> 01:01:01,780
from node to node the transmission is
1416
01:01:03,839 --> 01:01:04,839
guaranteed to be strong and clear
1417
01:01:05,280 --> 01:01:06,280
because each node is acting as a sort of
1418
01:01:07,680 --> 01:01:08,680
like booster for the signal uh also
1419
01:01:10,740 --> 01:01:11,740
because the data can only be transmitted
1420
01:01:13,380 --> 01:01:14,380
unidirectionally in One Direction
1421
01:01:15,180 --> 01:01:16,180
there's no collisions that are going to
1422
01:01:17,280 --> 01:01:18,280
happen on the network in other words uh
1423
01:01:19,799 --> 01:01:20,799
if this guy can't send data that way and
1424
01:01:22,559 --> 01:01:23,559
then this guy's sending this data that
1425
01:01:23,880 --> 01:01:24,880
way and then they sort of cancel each
1426
01:01:25,200 --> 01:01:26,200
other out
1427
01:01:27,180 --> 01:01:28,180
so we're going to eliminate uh you know
1428
01:01:31,079 --> 01:01:32,079
where problems can occur and that's
1429
01:01:33,240 --> 01:01:34,240
going to help administrators determine
1430
01:01:35,339 --> 01:01:36,339
where an issue is occurring if they're
1431
01:01:37,200 --> 01:01:38,200
having an issue with the network now
1432
01:01:39,059 --> 01:01:40,059
negatively if one of these nodes goes
1433
01:01:42,000 --> 01:01:43,000
down on the network the entire network
1434
01:01:43,980 --> 01:01:44,980
potentially goes down as well and also
1435
01:01:46,500 --> 01:01:47,500
because data can only transmit in One
1436
01:01:48,660 --> 01:01:49,660
Direction there's a high potential for
1437
01:01:50,940 --> 01:01:51,940
data to take a longer time to reach its
1438
01:01:53,579 --> 01:01:54,579
destination because obviously if I want
1439
01:01:55,799 --> 01:01:56,799
to send data
1440
01:01:58,440 --> 01:01:59,440
to this guy but I'm unidirectional I
1441
01:02:00,780 --> 01:02:01,780
actually have to go here then here then
1442
01:02:03,780 --> 01:02:04,780
here whereas if I was using a star
1443
01:02:05,880 --> 01:02:06,880
topology I could reduce that by one A
1444
01:02:09,359 --> 01:02:10,359
variation by the way of this physical
1445
01:02:10,859 --> 01:02:11,859
ring topology that attempts to correct
1446
01:02:13,500 --> 01:02:14,500
some of the limitations is what's called
1447
01:02:15,599 --> 01:02:16,599
a dual ring topology
1448
01:02:18,000 --> 01:02:19,000
I'm just drawing that out
1449
01:02:21,720 --> 01:02:22,720
and a dual ranked apology gives a sort
1450
01:02:24,000 --> 01:02:25,000
of redundancy uh to the network by
1451
01:02:26,760 --> 01:02:27,760
having a second ring either on the
1452
01:02:28,440 --> 01:02:29,440
inside or the outside of the first ring
1453
01:02:30,420 --> 01:02:31,420
and it allows data to flow in the
1454
01:02:33,660 --> 01:02:34,660
opposite direction
1455
01:02:39,720 --> 01:02:40,720
so this can double the speed of the
1456
01:02:41,640 --> 01:02:42,640
network by sending data through the path
1457
01:02:43,500 --> 01:02:44,500
that's going to be the shortest between
1458
01:02:44,760 --> 01:02:45,760
nodes so if a wants to talk to C
1459
01:02:49,500 --> 01:02:50,500
or actually we'll call that b just
1460
01:02:51,119 --> 01:02:52,119
because of where it is and we'll call
1461
01:02:52,319 --> 01:02:53,319
this one c
1462
01:02:53,520 --> 01:02:54,520
um if a wants to talk to B it knows to
1463
01:02:56,280 --> 01:02:57,280
take the blue line as opposed to the red
1464
01:02:58,980 --> 01:02:59,980
line because the blue line is going to
1465
01:03:00,900 --> 01:03:01,900
get it there faster
1466
01:03:02,579 --> 01:03:03,579
so dual Rings also allow the network to
1467
01:03:05,280 --> 01:03:06,280
continue to operate if one of these goes
1468
01:03:07,740 --> 01:03:08,740
down which I think you could probably
1469
01:03:09,480 --> 01:03:10,480
see from this so if the outside ring
1470
01:03:11,880 --> 01:03:12,880
fails and the inside ring can actually
1471
01:03:13,740 --> 01:03:14,740
pick up the slack for the outside ring
1472
01:03:17,520 --> 01:03:18,520
a physical tree topology it's much like
1473
01:03:20,460 --> 01:03:21,460
its namesake as as you can see it's a
1474
01:03:22,200 --> 01:03:23,200
tree each branch of the tree
1475
01:03:28,680 --> 01:03:29,680
can only receive its signal for from its
1476
01:03:32,700 --> 01:03:33,700
parent node or its linked branch
1477
01:03:35,460 --> 01:03:36,460
right so all of these can only receive a
1478
01:03:39,240 --> 01:03:40,240
signal from
1479
01:03:41,339 --> 01:03:42,339
this guy the root node is what we call
1480
01:03:44,339 --> 01:03:45,339
the top portion of the network and it
1481
01:03:47,460 --> 01:03:48,460
does not have a parent so it is the root
1482
01:03:49,920 --> 01:03:50,920
just like a tree it's the roots it's
1483
01:03:52,319 --> 01:03:53,319
directly connected to each of the child
1484
01:03:54,420 --> 01:03:55,420
nodes that's what these would be called
1485
01:03:58,200 --> 01:03:59,200
by a point-to-point connection
1486
01:04:00,960 --> 01:04:01,960
now depending on how many levels you
1487
01:04:02,819 --> 01:04:03,819
have here and we can see we have three
1488
01:04:04,799 --> 01:04:05,799
levels here uh your tree topology is
1489
01:04:08,160 --> 01:04:09,160
gonna have is gonna dictate what the
1490
01:04:11,040 --> 01:04:12,040
what we call the branching factor is and
1491
01:04:13,619 --> 01:04:14,619
this might be a little beyond the scope
1492
01:04:15,540 --> 01:04:16,540
of the exam but I'm going to cover it
1493
01:04:17,099 --> 01:04:18,099
here anyway the higher the branching
1494
01:04:19,440 --> 01:04:20,440
Factor the longer it's going to take
1495
01:04:21,599 --> 01:04:22,599
from data to go from one node through
1496
01:04:23,280 --> 01:04:24,280
the network to the other because
1497
01:04:24,540 --> 01:04:25,540
obviously if this needs to talk to this
1498
01:04:26,640 --> 01:04:27,640
then right we're going to have
1499
01:04:30,299 --> 01:04:31,299
quite a bit of data that it has to go
1500
01:04:32,460 --> 01:04:33,460
through
1501
01:04:34,380 --> 01:04:35,380
a positive aspect of this entire
1502
01:04:36,480 --> 01:04:37,480
topology by the way is that because each
1503
01:04:38,700 --> 01:04:39,700
level is connected only to its parent
1504
01:04:41,520 --> 01:04:42,520
and its child nodes
1505
01:04:44,520 --> 01:04:45,520
it's very easy to troubleshoot where the
1506
01:04:46,680 --> 01:04:47,680
problems in the network occur because
1507
01:04:49,140 --> 01:04:50,140
obviously if you're having a problem
1508
01:04:51,440 --> 01:04:52,440
with you know this connection over here
1509
01:04:54,240 --> 01:04:55,240
you know that none of these have
1510
01:04:55,980 --> 01:04:56,980
anything to do with it
1511
01:05:00,839 --> 01:05:01,839
it's also the other benefit is it's
1512
01:05:03,000 --> 01:05:04,000
really scalable
1513
01:05:04,319 --> 01:05:05,319
remember that word because obviously if
1514
01:05:06,780 --> 01:05:07,780
I want to add another Network I can just
1515
01:05:09,180 --> 01:05:10,180
add it either here or I can add another
1516
01:05:11,579 --> 01:05:12,579
child here and then just sort of Branch
1517
01:05:13,799 --> 01:05:14,799
off there now negatively if the
1518
01:05:16,980 --> 01:05:17,980
connection should be interrupted or if a
1519
01:05:19,079 --> 01:05:20,079
node that's sort of a higher level and
1520
01:05:21,299 --> 01:05:22,299
the change should go down then all these
1521
01:05:23,460 --> 01:05:24,460
subordinate nodes would suffer so if the
1522
01:05:25,380 --> 01:05:26,380
connection between the root and their
1523
01:05:26,640 --> 01:05:27,640
children goes down we're going to be in
1524
01:05:28,799 --> 01:05:29,799
major issue because now none of these
1525
01:05:30,480 --> 01:05:31,480
can talk obviously if this computer goes
1526
01:05:33,059 --> 01:05:34,059
down
1527
01:05:34,020 --> 01:05:35,020
then none of these will be able to talk
1528
01:05:35,940 --> 01:05:36,940
to the rest of the network either so
1529
01:05:37,859 --> 01:05:38,859
this is a a problem with it it is a
1530
01:05:41,400 --> 01:05:42,400
variation by the way of the bus topology
1531
01:05:44,579 --> 01:05:45,579
so again if the backbone fails then
1532
01:05:47,819 --> 01:05:48,819
nothing else is going to work
1533
01:05:49,680 --> 01:05:50,680
now with a physical mesh topology each
1534
01:05:52,799 --> 01:05:53,799
node in the network is directly
1535
01:05:54,660 --> 01:05:55,660
connected to every other node on the
1536
01:05:56,579 --> 01:05:57,579
network so if we call this computer a
1537
01:05:59,640 --> 01:06:00,640
you can see it's connected to
1538
01:06:03,359 --> 01:06:04,359
B it's connected directly to
1539
01:06:06,420 --> 01:06:07,420
C and it's also connected directly to D
1540
01:06:09,540 --> 01:06:10,540
so for every computer on the network
1541
01:06:11,940 --> 01:06:12,940
it's for every node on the network
1542
01:06:13,260 --> 01:06:14,260
rather it's connected to every other
1543
01:06:14,819 --> 01:06:15,819
node
1544
01:06:16,859 --> 01:06:17,859
as a result because each connection is
1545
01:06:20,760 --> 01:06:21,760
similar to like a point-to-point network
1546
01:06:22,819 --> 01:06:23,819
uh communication between multiple nodes
1547
01:06:25,920 --> 01:06:26,920
can happen at the same time and so it's
1548
01:06:28,440 --> 01:06:29,440
very efficient highly reliable and has
1549
01:06:31,559 --> 01:06:32,559
minimal data congestion because B and D
1550
01:06:34,079 --> 01:06:35,079
can talk at the same time as a and C now
1551
01:06:36,599 --> 01:06:37,599
for the same reason these types of
1552
01:06:38,579 --> 01:06:39,579
topologies the mesh topologies are very
1553
01:06:40,500 --> 01:06:41,500
difficult to manage and to maintain
1554
01:06:42,720 --> 01:06:43,720
because each additional node that's
1555
01:06:44,880 --> 01:06:45,880
added uh requires you to connect other
1556
01:06:50,280 --> 01:06:51,280
you know every single other node to it
1557
01:06:52,260 --> 01:06:53,260
so if I wanted to add an e for instance
1558
01:06:54,839 --> 01:06:55,839
look at all of the connections I now
1559
01:06:58,920 --> 01:06:59,920
have to add to this already existing
1560
01:07:01,980 --> 01:07:02,980
Network so to alleviate some of the
1561
01:07:04,200 --> 01:07:05,200
negatives of this type of network
1562
01:07:06,839 --> 01:07:07,839
um it's uh
1563
01:07:08,460 --> 01:07:09,460
we sometimes have what's called a
1564
01:07:09,960 --> 01:07:10,960
partial mesh the partial mesh basically
1565
01:07:12,599 --> 01:07:13,599
means only specific nodes on the network
1566
01:07:14,760 --> 01:07:15,760
have to have direct links and this is
1567
01:07:17,280 --> 01:07:18,280
sort of where we're going to go when we
1568
01:07:18,299 --> 01:07:19,299
get into hybrid topologies
1569
01:07:20,220 --> 01:07:21,220
it's going to limit the number of
1570
01:07:21,920 --> 01:07:22,920
connections that are necessary
1571
01:07:24,119 --> 01:07:25,119
throughout the network so a partial mesh
1572
01:07:26,700 --> 01:07:27,700
topology would be useful if your network
1573
01:07:28,319 --> 01:07:29,319
is comprised of say like end nodes that
1574
01:07:31,680 --> 01:07:32,680
don't need a connection to all the other
1575
01:07:33,599 --> 01:07:34,599
nodes on the network but it still allows
1576
01:07:35,940 --> 01:07:36,940
high end devices to maintain the maximum
1577
01:07:39,299 --> 01:07:40,299
transfer rates and the maximum amount of
1578
01:07:40,920 --> 01:07:41,920
efficiency and reliability the
1579
01:07:43,020 --> 01:07:44,020
internet's major divisions are connected
1580
01:07:44,940 --> 01:07:45,940
to one another by a mesh topology so
1581
01:07:47,160 --> 01:07:48,160
we're really going to see this in sort
1582
01:07:49,140 --> 01:07:50,140
of large scale
1583
01:07:51,740 --> 01:07:52,740
implementations that need
1584
01:07:56,099 --> 01:07:57,099
High redundancy
1585
01:08:01,380 --> 01:08:02,380
and efficiency I should add
1586
01:08:03,660 --> 01:08:04,660
now a hybrid topology as we have we as
1587
01:08:06,359 --> 01:08:07,359
we've discussed utilizes uh aspects of
1588
01:08:09,780 --> 01:08:10,780
more than one type of individual
1589
01:08:12,000 --> 01:08:13,000
topology so hybrid topologies are
1590
01:08:14,819 --> 01:08:15,819
usually not created on purpose they're
1591
01:08:17,160 --> 01:08:18,160
usually actually created out of
1592
01:08:18,359 --> 01:08:19,359
necessity so topologies like this can
1593
01:08:20,880 --> 01:08:21,880
maintain uh are difficult rather to
1594
01:08:23,699 --> 01:08:24,699
maintain and to manage because each
1595
01:08:25,679 --> 01:08:26,679
segment in the hybrid topology might
1596
01:08:27,839 --> 01:08:28,839
have its own set of rules it needs to
1597
01:08:29,580 --> 01:08:30,580
Follows the technology is on the
1598
01:08:31,440 --> 01:08:32,440
different segments might not be the same
1599
01:08:33,359 --> 01:08:34,359
either so I might have a different type
1600
01:08:35,339 --> 01:08:36,339
type of Technology on this segment than
1601
01:08:38,040 --> 01:08:39,040
I do on this segment and I might and
1602
01:08:39,960 --> 01:08:40,960
then I have a different type of
1603
01:08:41,219 --> 01:08:42,219
Technology on this segment right here so
1604
01:08:43,859 --> 01:08:44,859
there are a few common types of star of
1605
01:08:46,980 --> 01:08:47,980
topologies that are in a hybrid sort of
1606
01:08:49,319 --> 01:08:50,319
breed that we come across this one's
1607
01:08:51,480 --> 01:08:52,480
called a star bus obviously because we
1608
01:08:53,460 --> 01:08:54,460
have stars here and then the stars are
1609
01:08:56,160 --> 01:08:57,160
connected by a bus connection notice
1610
01:08:59,339 --> 01:09:00,339
again the Terminators on either side
1611
01:09:02,759 --> 01:09:03,759
we also have what's called a a star of
1612
01:09:05,940 --> 01:09:06,940
stars hybrid you can see that each star
1613
01:09:08,460 --> 01:09:09,460
is connected by another star so it's not
1614
01:09:11,759 --> 01:09:12,759
only different topologies but when we
1615
01:09:13,920 --> 01:09:14,920
connect the topologies together uh sort
1616
01:09:16,199 --> 01:09:17,199
of in different ways that can be a
1617
01:09:18,239 --> 01:09:19,239
different hyper topology as well and
1618
01:09:20,580 --> 01:09:21,580
then another popular one is the star
1619
01:09:22,380 --> 01:09:23,380
ring topology so similar to bus except
1620
01:09:25,500 --> 01:09:26,500
there's no Terminators on the end
1621
01:09:26,699 --> 01:09:27,699
because everything connects together you
1622
01:09:28,560 --> 01:09:29,560
might also have a star dual ring
1623
01:09:29,880 --> 01:09:30,880
topology which I have seen uh all the
1624
01:09:32,520 --> 01:09:33,520
very infrequently by the way this one is
1625
01:09:35,219 --> 01:09:36,219
also called although I doubt you'll see
1626
01:09:36,779 --> 01:09:37,779
this
1627
01:09:37,940 --> 01:09:38,940
snowflake topology
1628
01:09:40,739 --> 01:09:41,739
now Network
1629
01:09:42,620 --> 01:09:43,620
Protocols are the controlling factor and
1630
01:09:45,839 --> 01:09:46,839
how all these topologies are going to
1631
01:09:47,520 --> 01:09:48,520
transmit data and depending on the
1632
01:09:51,420 --> 01:09:52,420
protocol data it might need to be
1633
01:09:52,799 --> 01:09:53,799
transmitted to all the nodes on the
1634
01:09:54,420 --> 01:09:55,420
network regardless of the physical
1635
01:09:55,980 --> 01:09:56,980
connection so this is why having a
1636
01:09:58,440 --> 01:09:59,440
logical topology is different from a
1637
01:10:00,540 --> 01:10:01,540
physical topology in other words the way
1638
01:10:03,420 --> 01:10:04,420
the data is transferred over the network
1639
01:10:05,699 --> 01:10:06,699
might be different than the way the
1640
01:10:08,280 --> 01:10:09,280
physical network is actually
1641
01:10:10,140 --> 01:10:11,140
connected so let me give an example with
1642
01:10:12,239 --> 01:10:13,239
this logical bus topology
1643
01:10:15,420 --> 01:10:16,420
okay data is received by all nodes
1644
01:10:18,620 --> 01:10:19,620
simultaneously even when the physical
1645
01:10:22,080 --> 01:10:23,080
setup is different so for example we're
1646
01:10:24,540 --> 01:10:25,540
using a logical bus topology with this
1647
01:10:27,360 --> 01:10:28,360
physical star so the central device is
1648
01:10:31,199 --> 01:10:32,199
receiving the transmission from let's
1649
01:10:33,480 --> 01:10:34,480
say the sending node which is this one
1650
01:10:36,000 --> 01:10:37,000
so let's say a is sending it out
1651
01:10:38,280 --> 01:10:39,280
and then it's passing it to each node in
1652
01:10:40,800 --> 01:10:41,800
succession in a continuous stream in
1653
01:10:42,960 --> 01:10:43,960
other words it's doing this
1654
01:10:45,000 --> 01:10:46,000
it's going down there and then it's
1655
01:10:47,159 --> 01:10:48,159
sending it here and then it's sending it
1656
01:10:49,440 --> 01:10:50,440
there and then it's sending it there and
1657
01:10:51,780 --> 01:10:52,780
then it's sending it there so you can
1658
01:10:53,699 --> 01:10:54,699
see what it's doing is although it's
1659
01:10:55,020 --> 01:10:56,020
connected in a star physically the nodes
1660
01:10:57,719 --> 01:10:58,719
are talking to one another as though
1661
01:10:58,980 --> 01:10:59,980
they are logical
1662
01:11:00,540 --> 01:11:01,540
now with a logical ring topology uh just
1663
01:11:04,560 --> 01:11:05,560
like with a physical ring the data is
1664
01:11:06,600 --> 01:11:07,600
only transmitted between its upstream
1665
01:11:08,520 --> 01:11:09,520
and its Downstream neighbors so even
1666
01:11:10,739 --> 01:11:11,739
though the star layout is physically
1667
01:11:12,960 --> 01:11:13,960
laid out in a certain way the data from
1668
01:11:16,020 --> 01:11:17,020
the transmitting devices is sent
1669
01:11:19,380 --> 01:11:20,380
in specific order
1670
01:11:22,020 --> 01:11:23,020
one to the next
1671
01:11:25,679 --> 01:11:26,679
now actually most ring
1672
01:11:30,120 --> 01:11:31,120
networks are physical Stars
1673
01:11:33,900 --> 01:11:34,900
right so every time the data is sent it
1674
01:11:36,719 --> 01:11:37,719
has to be sent to its up Downstream
1675
01:11:38,580 --> 01:11:39,580
neighbor
1676
01:11:40,860 --> 01:11:41,860
in succession like so
1677
01:11:43,080 --> 01:11:44,080
so it just goes in a circular route
1678
01:11:47,520 --> 01:11:48,520
we also have of course The Logical star
1679
01:11:50,040 --> 01:11:51,040
topology which can utilize a central
1680
01:11:52,320 --> 01:11:53,320
device
1681
01:11:54,179 --> 01:11:55,179
and it's going to pull each node to see
1682
01:11:56,340 --> 01:11:57,340
if it has the data to be transmitted so
1683
01:11:59,219 --> 01:12:00,219
basically it says hey uh do you have any
1684
01:12:01,920 --> 01:12:02,920
data you want to transmit okay do you
1685
01:12:03,840 --> 01:12:04,840
have any data you want to transmit all
1686
01:12:05,219 --> 01:12:06,219
right do you have any data oh you do
1687
01:12:06,600 --> 01:12:07,600
great then it'll transmit that data and
1688
01:12:08,880 --> 01:12:09,880
then come back around so the device
1689
01:12:11,159 --> 01:12:12,159
ensures that each node has an
1690
01:12:13,380 --> 01:12:14,380
opportunity to transmit but it also
1691
01:12:15,480 --> 01:12:16,480
governs how long that's going to happen
1692
01:12:16,739 --> 01:12:17,739
for and it's going to make sure that
1693
01:12:18,840 --> 01:12:19,840
there's not any
1694
01:12:20,760 --> 01:12:21,760
sort of problems or uh
1695
01:12:24,060 --> 01:12:25,060
collisions with the data
1696
01:12:26,699 --> 01:12:27,699
so just to recap what we just talked
1697
01:12:29,040 --> 01:12:30,040
about albeit a a 5 000 foot overview of
1698
01:12:33,060 --> 01:12:34,060
it we talked about topology which again
1699
01:12:35,640 --> 01:12:36,640
is like how the network is arranged that
1700
01:12:39,060 --> 01:12:40,060
Arrangement can either be physical
1701
01:12:40,860 --> 01:12:41,860
meaning how it is physically connected
1702
01:12:42,840 --> 01:12:43,840
or logical
1703
01:12:45,480 --> 01:12:46,480
we then talked about a bus topology the
1704
01:12:48,300 --> 01:12:49,300
bus topology meaning that it is
1705
01:12:52,739 --> 01:12:53,739
connected to each device one in sequence
1706
01:12:55,560 --> 01:12:56,560
we also need to terminate these with a
1707
01:12:57,719 --> 01:12:58,719
50 ohm
1708
01:12:59,040 --> 01:13:00,040
Terminator on either side and remember
1709
01:13:01,199 --> 01:13:02,199
we have a t connector that's connecting
1710
01:13:03,060 --> 01:13:04,060
them
1711
01:13:03,719 --> 01:13:04,719
we looked at a star topology
1712
01:13:08,219 --> 01:13:09,219
which means that these are all connected
1713
01:13:09,540 --> 01:13:10,540
through a central device a ring
1714
01:13:15,719 --> 01:13:16,719
topology
1715
01:13:18,120 --> 01:13:19,120
tree topology
1716
01:13:20,460 --> 01:13:21,460
which has branches
1717
01:13:22,679 --> 01:13:23,679
this might also be called by the way a
1718
01:13:24,360 --> 01:13:25,360
hierarchical
1719
01:13:25,560 --> 01:13:26,560
hierarchical
1720
01:13:28,620 --> 01:13:29,620
topology and so on and then a mesh
1721
01:13:31,500 --> 01:13:32,500
topology
1722
01:13:33,719 --> 01:13:34,719
which would be every device connected to
1723
01:13:36,239 --> 01:13:37,239
every other device
1724
01:13:40,620 --> 01:13:41,620
and then we also looked at a hybrid
1725
01:13:45,360 --> 01:13:46,360
of these
1726
01:13:49,320 --> 01:13:50,320
most commonly we're going to see a
1727
01:13:52,320 --> 01:13:53,320
physical star
1728
01:13:53,699 --> 01:13:54,699
with a logical ring
1729
01:13:56,760 --> 01:13:57,760
so it's important that as administrators
1730
01:14:00,540 --> 01:14:01,540
we have an understanding of how the
1731
01:14:02,520 --> 01:14:03,520
network is designed both physically and
1732
01:14:04,920 --> 01:14:05,920
logically in other words how the data
1733
01:14:06,540 --> 01:14:07,540
transmits over that physical stuff
1734
01:14:11,660 --> 01:14:12,660
[Music]
1735
01:14:20,239 --> 01:14:21,239
thank you
1736
01:14:31,500 --> 01:14:32,500
Network hardware and media bounded
1737
01:14:34,920 --> 01:14:35,920
Network media
1738
01:14:37,500 --> 01:14:38,500
having discussed some of the basic
1739
01:14:40,679 --> 01:14:41,679
terminology and some of the basic
1740
01:14:43,140 --> 01:14:44,140
Network setups I want to get into now
1741
01:14:45,420 --> 01:14:46,420
the hardware the media how this stuff
1742
01:14:48,480 --> 01:14:49,480
actually physically connects to one
1743
01:14:50,760 --> 01:14:51,760
another
1744
01:14:51,600 --> 01:14:52,600
so we're going to discuss the different
1745
01:14:53,280 --> 01:14:54,280
network hardware and media types in this
1746
01:14:55,920 --> 01:14:56,920
module
1747
01:14:57,179 --> 01:14:58,179
so the objectives that we're going to
1748
01:14:58,620 --> 01:14:59,620
cover are first defining Network media
1749
01:15:01,620 --> 01:15:02,620
and specifically bounded Network media
1750
01:15:04,800 --> 01:15:05,800
bounded Network media meaning the stuff
1751
01:15:06,900 --> 01:15:07,900
that you can hold bounded contained in
1752
01:15:10,080 --> 01:15:11,080
chords and wires unlike unbounded which
1753
01:15:13,199 --> 01:15:14,199
is Wireless we're then going to describe
1754
01:15:15,600 --> 01:15:16,600
the different types of copper media and
1755
01:15:18,239 --> 01:15:19,239
also explain the different types of STP
1756
01:15:21,000 --> 01:15:22,000
that's shielded twisted pair and UTP
1757
01:15:27,140 --> 01:15:28,140
unshielded twisted pair
1758
01:15:29,400 --> 01:15:30,400
then we'll describe the different types
1759
01:15:31,020 --> 01:15:32,020
of coaxial cable types and connectors
1760
01:15:33,300 --> 01:15:34,300
and finally describe fiber optic median
1761
01:15:36,540 --> 01:15:37,540
connectors fiber optics being that type
1762
01:15:38,940 --> 01:15:39,940
of
1763
01:15:39,800 --> 01:15:40,800
media that is that transmits data via
1764
01:15:44,159 --> 01:15:45,159
light and photons rather than
1765
01:15:47,040 --> 01:15:48,040
electricity over copper
1766
01:15:49,739 --> 01:15:50,739
after that I want to explain the 568 a b
1767
01:15:53,219 --> 01:15:54,219
and c standards which is how uh standard
1768
01:15:56,400 --> 01:15:57,400
UTP and STP is cabled on one end and on
1769
01:16:00,420 --> 01:16:01,420
the other so we can plug it in and
1770
01:16:02,580 --> 01:16:03,580
finally explain something called premise
1771
01:16:04,140 --> 01:16:05,140
wiring and structured cabling
1772
01:16:06,780 --> 01:16:07,780
so Network media is simply the method or
1773
01:16:10,560 --> 01:16:11,560
medium by which data will be transmitted
1774
01:16:14,179 --> 01:16:15,179
it's further classified based on the
1775
01:16:17,400 --> 01:16:18,400
hardware and Associated technology of
1776
01:16:20,280 --> 01:16:21,280
the media itself now there are both
1777
01:16:22,620 --> 01:16:23,620
wired and wireless Technologies
1778
01:16:25,400 --> 01:16:26,400
associated with network media so in this
1779
01:16:28,560 --> 01:16:29,560
one we're going to take a look at the
1780
01:16:29,760 --> 01:16:30,760
first one wired Network media which is
1781
01:16:32,460 --> 01:16:33,460
also characterized as bounded because it
1782
01:16:34,920 --> 01:16:35,920
is bounded by a chord
1783
01:16:36,840 --> 01:16:37,840
so bounded media is media that can be
1784
01:16:40,020 --> 01:16:41,020
physically held there are a few types of
1785
01:16:42,300 --> 01:16:43,300
bound media that we need to be familiar
1786
01:16:43,980 --> 01:16:44,980
with we're going to look at either
1787
01:16:45,480 --> 01:16:46,480
copper or Fiber now bounded Network
1788
01:16:48,840 --> 01:16:49,840
media is the basic and original form of
1789
01:16:51,840 --> 01:16:52,840
media and as administrators you're very
1790
01:16:55,199 --> 01:16:56,199
likely if not guaranteed at some point
1791
01:16:57,840 --> 01:16:58,840
to have to work with it in one form or
1792
01:16:59,699 --> 01:17:00,699
another
1793
01:17:00,360 --> 01:17:01,360
so having a solid understanding of the
1794
01:17:02,640 --> 01:17:03,640
different types of bounded media will
1795
01:17:05,040 --> 01:17:06,040
help you succeed in managing any type of
1796
01:17:07,739 --> 01:17:08,739
network whether it's at your home a
1797
01:17:10,020 --> 01:17:11,020
small office or even a very large
1798
01:17:12,000 --> 01:17:13,000
corporate win or wide area network so
1799
01:17:15,000 --> 01:17:16,000
the first type of bound Network media I
1800
01:17:16,980 --> 01:17:17,980
want to go over is copper media
1801
01:17:19,920 --> 01:17:20,920
copper media is the term used to
1802
01:17:22,860 --> 01:17:23,860
describe any media that uses copper
1803
01:17:25,679 --> 01:17:26,679
conductors as the method to transmit
1804
01:17:28,199 --> 01:17:29,199
data in the form of
1805
01:17:30,440 --> 01:17:31,440
electromagnetic energy so copper media
1806
01:17:33,600 --> 01:17:34,600
can come in many different forms there
1807
01:17:36,300 --> 01:17:37,300
are also many considerations that need
1808
01:17:38,219 --> 01:17:39,219
to be taken into account when choosing
1809
01:17:40,440 --> 01:17:41,440
between these different types of forms
1810
01:17:42,360 --> 01:17:43,360
such as a distance the speed
1811
01:17:45,300 --> 01:17:46,300
requirements of the network and of
1812
01:17:47,520 --> 01:17:48,520
course the cost
1813
01:17:48,900 --> 01:17:49,900
a lot of the time uh copper media was
1814
01:17:51,900 --> 01:17:52,900
going to be fitted with some sort of
1815
01:17:53,580 --> 01:17:54,580
shielding which also looks like braided
1816
01:17:56,040 --> 01:17:57,040
metal wires or sometimes it looks like a
1817
01:17:57,960 --> 01:17:58,960
metallic foil like you buy at the
1818
01:17:59,699 --> 01:18:00,699
grocery store but it is a little
1819
01:18:01,140 --> 01:18:02,140
different the shielding on the outside
1820
01:18:03,120 --> 01:18:04,120
helps the cable prevent or helps prevent
1821
01:18:07,739 --> 01:18:08,739
the cable from being uh subjected to
1822
01:18:11,159 --> 01:18:12,159
what's called electromagnetic
1823
01:18:12,719 --> 01:18:13,719
interference or Emi and of course if I
1824
01:18:17,520 --> 01:18:18,520
allow Emi or electromagnetic
1825
01:18:19,260 --> 01:18:20,260
interference to get into the copper
1826
01:18:21,420 --> 01:18:22,420
within the cable then that's going to
1827
01:18:23,219 --> 01:18:24,219
disrupt the sort of data that's going on
1828
01:18:25,020 --> 01:18:26,020
inside of it now there are two uh
1829
01:18:28,260 --> 01:18:29,260
different types of very common copper
1830
01:18:30,600 --> 01:18:31,600
media that I want to go off uh uh
1831
01:18:32,880 --> 01:18:33,880
specifically of coaxial or coax as shown
1832
01:18:37,020 --> 01:18:38,020
here and twisted pair
1833
01:18:39,600 --> 01:18:40,600
now twisted pair table is one of the
1834
01:18:42,840 --> 01:18:43,840
most common cable types that you need to
1835
01:18:44,699 --> 01:18:45,699
be familiar with depending on the
1836
01:18:46,800 --> 01:18:47,800
specification of the cable and the type
1837
01:18:48,780 --> 01:18:49,780
of twisted pair cable being used there's
1838
01:18:51,239 --> 01:18:52,239
going to be anywhere from two to a
1839
01:18:53,460 --> 01:18:54,460
hundred pairs or more
1840
01:18:55,739 --> 01:18:56,739
now the pairs are color coded so the
1841
01:18:58,679 --> 01:18:59,679
technicians know how to recable the
1842
01:19:01,320 --> 01:19:02,320
cables on either end and it ensures that
1843
01:19:03,659 --> 01:19:04,659
certain wiring standards and schemes are
1844
01:19:05,940 --> 01:19:06,940
maintained in case another technician
1845
01:19:07,560 --> 01:19:08,560
was to come in and start or end the work
1846
01:19:09,300 --> 01:19:10,300
that you've already begun
1847
01:19:10,800 --> 01:19:11,800
now all twisted pair cables are
1848
01:19:13,380 --> 01:19:14,380
basically the same however it's how they
1849
01:19:16,080 --> 01:19:17,080
are terminated that makes the biggest
1850
01:19:17,640 --> 01:19:18,640
difference meaning how the end points so
1851
01:19:20,640 --> 01:19:21,640
what happens at the end points now there
1852
01:19:22,739 --> 01:19:23,739
are two typical types of standards that
1853
01:19:25,140 --> 01:19:26,140
we need to be aware of these are uh
1854
01:19:28,159 --> 01:19:29,159
t568 a and t568b so we're going to take
1855
01:19:33,540 --> 01:19:34,540
a look at these right now
1856
01:19:35,640 --> 01:19:36,640
now 568a it's less common than 568b
1857
01:19:40,080 --> 01:19:41,080
today in today's networks but it's still
1858
01:19:42,360 --> 01:19:43,360
necessary for you to know and you need
1859
01:19:43,980 --> 01:19:44,980
to understand the difference between the
1860
01:19:45,480 --> 01:19:46,480
two of these uh and it'll also help you
1861
01:19:48,840 --> 01:19:49,840
in case you ever wanted to make a cable
1862
01:19:50,040 --> 01:19:51,040
at home
1863
01:19:51,320 --> 01:19:52,320
568 a is wired in this way green white
1864
01:19:55,800 --> 01:19:56,800
green
1865
01:19:57,120 --> 01:19:58,120
orange white
1866
01:19:58,679 --> 01:19:59,679
blue
1867
01:20:00,000 --> 01:20:01,000
White
1868
01:20:01,440 --> 01:20:02,440
Orange
1869
01:20:02,940 --> 01:20:03,940
brown white brown
1870
01:20:05,340 --> 01:20:06,340
now the only difference between the 568
1871
01:20:08,580 --> 01:20:09,580
a cabling standard and 568b is that the
1872
01:20:13,020 --> 01:20:14,020
first two pins one and two are swapped
1873
01:20:16,080 --> 01:20:17,080
with pins three and six that means that
1874
01:20:19,560 --> 01:20:20,560
the orange colored wires are swapped
1875
01:20:22,199 --> 01:20:23,199
with the green colored wires so then in
1876
01:20:24,840 --> 01:20:25,840
568b we see a wiring of orange white
1877
01:20:28,040 --> 01:20:29,040
orange green white blue
1878
01:20:32,400 --> 01:20:33,400
blue white green
1879
01:20:34,980 --> 01:20:35,980
brown white and brown
1880
01:20:38,699 --> 01:20:39,699
now
1881
01:20:40,080 --> 01:20:41,080
the reason you need to know both of
1882
01:20:41,940 --> 01:20:42,940
those is because of something called
1883
01:20:43,380 --> 01:20:44,380
crossover cables which we'll talk about
1884
01:20:45,179 --> 01:20:46,179
by switching those uh pins around it
1885
01:20:48,360 --> 01:20:49,360
switches the data and how it's sent and
1886
01:20:50,580 --> 01:20:51,580
we'll talk about the purpose of that a
1887
01:20:52,620 --> 01:20:53,620
little bit later on
1888
01:20:54,120 --> 01:20:55,120
but for now let's talk about something
1889
01:20:55,679 --> 01:20:56,679
called STP or shielded twisted pair
1890
01:20:59,219 --> 01:21:00,219
cabling which is a cable type that
1891
01:21:01,920 --> 01:21:02,920
contains pairs of copper strands like we
1892
01:21:04,440 --> 01:21:05,440
just looked at orange white and orange
1893
01:21:06,120 --> 01:21:07,120
for instance being a pair that are
1894
01:21:08,580 --> 01:21:09,580
twisted together and wrapped with a
1895
01:21:10,980 --> 01:21:11,980
metal sheath or a kind of foil that
1896
01:21:14,400 --> 01:21:15,400
decreases the cable susceptibility as
1897
01:21:16,380 --> 01:21:17,380
we've already mentioned to Emi now
1898
01:21:18,659 --> 01:21:19,659
because it's wrapped in its metal it
1899
01:21:20,880 --> 01:21:21,880
makes the cable much more expensive than
1900
01:21:23,580 --> 01:21:24,580
its counterpart UTP or unshielded
1901
01:21:27,120 --> 01:21:28,120
twisted pair and it can make it more
1902
01:21:29,040 --> 01:21:30,040
difficult therefore to manage or work
1903
01:21:30,900 --> 01:21:31,900
with now although it has the shielding
1904
01:21:33,300 --> 01:21:34,300
to prevent it from Emi it doesn't mean
1905
01:21:35,640 --> 01:21:36,640
the cable is prevented completely from
1906
01:21:38,760 --> 01:21:39,760
any sort of susceptibility it just
1907
01:21:40,679 --> 01:21:41,679
reduces it I also want to mention the
1908
01:21:42,840 --> 01:21:43,840
reason that we have that twisted pair
1909
01:21:45,440 --> 01:21:46,440
each pair of cables for instance orange
1910
01:21:48,239 --> 01:21:49,239
and white orange are twisted together is
1911
01:21:51,420 --> 01:21:52,420
to reduce what we call crosstalk meaning
1912
01:21:54,060 --> 01:21:55,060
that so that the data doesn't sort of
1913
01:21:56,699 --> 01:21:57,699
jump between the two cables this was
1914
01:21:58,560 --> 01:21:59,560
something that was actually discovered
1915
01:21:59,760 --> 01:22:00,760
way back when when Edison was dealing
1916
01:22:01,800 --> 01:22:02,800
with electricity now UTP or unshielded
1917
01:22:04,860 --> 01:22:05,860
twisted pair cabling does not have that
1918
01:22:06,840 --> 01:22:07,840
metal shielding around the Twisted pairs
1919
01:22:08,580 --> 01:22:09,580
this is the only difference now this
1920
01:22:10,679 --> 01:22:11,679
makes the cable much more susceptible to
1921
01:22:12,480 --> 01:22:13,480
Emi than sdp however it's so inexpensive
1922
01:22:15,239 --> 01:22:16,239
and so much easier to install and
1923
01:22:18,239 --> 01:22:19,239
maneuver with and in most instances a
1924
01:22:20,940 --> 01:22:21,940
lot of folks don't need the extra Emi
1925
01:22:23,040 --> 01:22:24,040
protection so it's why it's one of the
1926
01:22:24,719 --> 01:22:25,719
most common
1927
01:22:25,860 --> 01:22:26,860
now there are several specific
1928
01:22:27,780 --> 01:22:28,780
implementations of sdp and UDP and each
1929
01:22:30,960 --> 01:22:31,960
one has different standards uh and
1930
01:22:33,060 --> 01:22:34,060
characteristics and speeds and so on so
1931
01:22:35,340 --> 01:22:36,340
let's take a look at those in a little
1932
01:22:37,260 --> 01:22:38,260
more depth right now
1933
01:22:38,960 --> 01:22:39,960
you may have heard of the or seen the
1934
01:22:42,480 --> 01:22:43,480
terms CAT5 or category five or Cat6 or
1935
01:22:46,440 --> 01:22:47,440
something similar to this before let's
1936
01:22:48,600 --> 01:22:49,600
take a look at what these terms mean and
1937
01:22:50,520 --> 01:22:51,520
what the specifications are regarding
1938
01:22:52,440 --> 01:22:53,440
them because you'll need to know that
1939
01:22:53,699 --> 01:22:54,699
for the exam
1940
01:22:55,080 --> 01:22:56,080
cat simply stands for category there are
1941
01:22:59,640 --> 01:23:00,640
both STP and UTP versions of these
1942
01:23:02,760 --> 01:23:03,760
category cables that stand if you recall
1943
01:23:05,640 --> 01:23:06,640
that's shielded and unshielded and the
1944
01:23:08,340 --> 01:23:09,340
first category of cable is as you'd
1945
01:23:10,620 --> 01:23:11,620
imagine category one cable now we don't
1946
01:23:13,500 --> 01:23:14,500
really see this in the field anymore
1947
01:23:14,820 --> 01:23:15,820
it's been superseded by the following
1948
01:23:18,060 --> 01:23:19,060
categories cabling and but its original
1949
01:23:19,980 --> 01:23:20,980
purpose was for voice I wouldn't worry
1950
01:23:22,380 --> 01:23:23,380
about memorizing that one
1951
01:23:24,179 --> 01:23:25,179
type 2 or Category 2 is rarely used
1952
01:23:27,840 --> 01:23:28,840
today uh only in something called token
1953
01:23:31,860 --> 01:23:32,860
based networks which we'll talk more
1954
01:23:33,300 --> 01:23:34,300
about in the future but again it's not
1955
01:23:35,219 --> 01:23:36,219
very common you're not really going to
1956
01:23:36,659 --> 01:23:37,659
see it uh very much at all
1957
01:23:39,120 --> 01:23:40,120
now Category 3 or ethernet which is
1958
01:23:42,659 --> 01:23:43,659
different from the current ethernet but
1959
01:23:44,040 --> 01:23:45,040
this was the first category established
1960
01:23:46,020 --> 01:23:47,020
by an organization called Tia eia this
1961
01:23:50,460 --> 01:23:51,460
is the Telecommunications industry
1962
01:23:52,380 --> 01:23:53,380
Association Electronics Industries
1963
01:23:54,120 --> 01:23:55,120
Alliance don't worry about memorizing
1964
01:23:56,159 --> 01:23:57,159
that but in today's networks category
1965
01:23:58,980 --> 01:23:59,980
three or cat 3 is used almost completely
1966
01:24:01,800 --> 01:24:02,800
for voice Transmissions because it has a
1967
01:24:04,500 --> 01:24:05,500
limited transfer speed of 10 megabits
1968
01:24:07,020 --> 01:24:08,020
per second and a 16 megahertz bandwidth
1969
01:24:09,840 --> 01:24:10,840
so a lot of
1970
01:24:11,760 --> 01:24:12,760
telephone K old telephone cableing is
1971
01:24:15,000 --> 01:24:16,000
cat 3. cat4 uh just like cat 2 it's not
1972
01:24:19,980 --> 01:24:20,980
used anymore not even worth really
1973
01:24:22,080 --> 01:24:23,080
spending time in now when we get to CAT5
1974
01:24:24,719 --> 01:24:25,719
this is sort of where we start really
1975
01:24:26,640 --> 01:24:27,640
getting to Modern Day stuff Cat 5
1976
01:24:29,159 --> 01:24:30,159
cabling which is also called Fast
1977
01:24:30,900 --> 01:24:31,900
ethernet provides performance of signals
1978
01:24:33,659 --> 01:24:34,659
up to around 100 megabits per second
1979
01:24:37,620 --> 01:24:38,620
important that you know this the maximum
1980
01:24:39,719 --> 01:24:40,719
distance for CAT5 cabling is 100 meters
1981
01:24:43,199 --> 01:24:44,199
or 328 feet
1982
01:24:45,719 --> 01:24:46,719
now CAT5 e is the specification that
1983
01:24:49,440 --> 01:24:50,440
superseded CAT5 and it addressed some of
1984
01:24:52,140 --> 01:24:53,140
the weaknesses including uh crosstalk
1985
01:24:54,840 --> 01:24:55,840
prevent prevention uh and other
1986
01:24:57,900 --> 01:24:58,900
specifications in the like like CAT5 the
1987
01:25:01,679 --> 01:25:02,679
maximum cable length of Cat5e is also
1988
01:25:04,679 --> 01:25:05,679
100 meters the bandwidth is also the
1989
01:25:07,620 --> 01:25:08,620
same at 100 megahertz but it's said that
1990
01:25:10,860 --> 01:25:11,860
data data rates can get up to about 350
1991
01:25:14,100 --> 01:25:15,100
megabits per second uh although
1992
01:25:16,920 --> 01:25:17,920
sometimes an application that's not
1993
01:25:18,659 --> 01:25:19,659
exactly what we see
1994
01:25:20,719 --> 01:25:21,719
Cat6 is a standard uh that increased the
1995
01:25:25,440 --> 01:25:26,440
transmission speeds quite a bit it's
1996
01:25:28,440 --> 01:25:29,440
what's called gigabit Ethernet because
1997
01:25:30,540 --> 01:25:31,540
it's rated for data rates of about one
1998
01:25:32,760 --> 01:25:33,760
gigabit per second so we're going from
1999
01:25:35,460 --> 01:25:36,460
again with 10 cat 3 from 10 Cat 5 100
2000
01:25:40,640 --> 01:25:41,640
Cat5e 350 theoretical and now we're at
2001
01:25:43,920 --> 01:25:44,920
1000 megabits per second or one gigabit
2002
01:25:46,080 --> 01:25:47,080
per second
2003
01:25:47,040 --> 01:25:48,040
the signal limb rate also of CAT5 Cat6
2004
01:25:50,100 --> 01:25:51,100
rather is tested at 250 megahertz uh but
2005
01:25:53,940 --> 01:25:54,940
it's guaranteed at a 200.
2006
01:25:57,000 --> 01:25:58,000
there was also another one after this
2007
01:25:58,739 --> 01:25:59,739
called cat6a which was also known as
2008
01:26:02,100 --> 01:26:03,100
augmented category six and it had a
2009
01:26:05,100 --> 01:26:06,100
rating of a little bit more than a one
2010
01:26:06,960 --> 01:26:07,960
gigabit but uh many people said that
2011
01:26:09,840 --> 01:26:10,840
they can actually get to 10 gigabits and
2012
01:26:11,880 --> 01:26:12,880
uh uh it's megahertz or frequency was
2013
01:26:14,580 --> 01:26:15,580
also Higher by the way I wouldn't worry
2014
01:26:16,440 --> 01:26:17,440
about any of the frequencies I'm just
2015
01:26:17,820 --> 01:26:18,820
throwing those in there so that you know
2016
01:26:19,440 --> 01:26:20,440
them what you really want to worry about
2017
01:26:20,699 --> 01:26:21,699
is the data transfer speed
2018
01:26:22,800 --> 01:26:23,800
a cat 7 which is one of the newest
2019
01:26:25,440 --> 01:26:26,440
implementations uh it's not even fully
2020
01:26:28,080 --> 01:26:29,080
recognized yet by Tia eia it's
2021
01:26:31,739 --> 01:26:32,739
um also gigabit Ethernet and it
2022
01:26:34,080 --> 01:26:35,080
supposedly supports a signaling rate of
2023
01:26:35,940 --> 01:26:36,940
one gigahertz and has a potential for
2024
01:26:38,699 --> 01:26:39,699
over 10 gigabits per second so you can
2025
01:26:41,040 --> 01:26:42,040
see where we're we want to go there but
2026
01:26:43,260 --> 01:26:44,260
at the same time Wireless technology or
2027
01:26:45,239 --> 01:26:46,239
unbounded technology has taken us to a
2028
01:26:47,580 --> 01:26:48,580
point where we might not need to spend
2029
01:26:49,199 --> 01:26:50,199
as much time on some of the bounded
2030
01:26:51,659 --> 01:26:52,659
media
2031
01:26:52,560 --> 01:26:53,560
so
2032
01:26:55,020 --> 01:26:56,020
now that we've seen all of these
2033
01:26:56,460 --> 01:26:57,460
individually
2034
01:26:57,600 --> 01:26:58,600
let's take a look at an easier breakdown
2035
01:27:00,480 --> 01:27:01,480
of the specifics of all of these
2036
01:27:03,300 --> 01:27:04,300
so as we can see here each of these cat
2037
01:27:06,000 --> 01:27:07,000
standards has a maximum cable length of
2038
01:27:08,639 --> 01:27:09,639
100 meters for standard use and the
2039
01:27:11,280 --> 01:27:12,280
frequencies and maximum data ranges go
2040
01:27:13,380 --> 01:27:14,380
up with each of the standards as well in
2041
01:27:16,139 --> 01:27:17,139
most cases when you're looking at the
2042
01:27:17,639 --> 01:27:18,639
physical cable the exact specification
2043
01:27:20,940 --> 01:27:21,940
is typically printed on the cable itself
2044
01:27:23,719 --> 01:27:24,719
helping technicians ensure that the same
2045
01:27:26,400 --> 01:27:27,400
standard is going to be used throughout
2046
01:27:28,380 --> 01:27:29,380
the organization
2047
01:27:29,699 --> 01:27:30,699
now while Cat 5 through 7 cables are
2048
01:27:33,480 --> 01:27:34,480
very similar because they all use the
2049
01:27:36,179 --> 01:27:37,179
RJ45 connector which is the connector at
2050
01:27:38,580 --> 01:27:39,580
the end that plugs into your network
2051
01:27:39,840 --> 01:27:40,840
card or into a port uh should a
2052
01:27:43,139 --> 01:27:44,139
technician install a Cat5e cable and a
2053
01:27:46,679 --> 01:27:47,679
cat 6 or higher Network the Network's
2054
01:27:49,440 --> 01:27:50,440
still probably going to function
2055
01:27:51,179 --> 01:27:52,179
correctly but the Network's only going
2056
01:27:53,340 --> 01:27:54,340
to operate
2057
01:27:55,080 --> 01:27:56,080
at the uh maximum speed of the lowest
2058
01:27:58,620 --> 01:27:59,620
standard so if everyone else in the
2059
01:28:00,540 --> 01:28:01,540
network has Cat6 and you install a Cat5e
2060
01:28:03,719 --> 01:28:04,719
cable then you're limited now to the
2061
01:28:05,340 --> 01:28:06,340
Cat5e
2062
01:28:07,080 --> 01:28:08,080
um specifications
2063
01:28:08,880 --> 01:28:09,880
now here's a picture of an RJ45
2064
01:28:11,219 --> 01:28:12,219
connector I want you to note there are
2065
01:28:13,380 --> 01:28:14,380
eight pins which means there are uh four
2066
01:28:16,620 --> 01:28:17,620
Twisted Pairs and next here's a picture
2067
01:28:19,139 --> 01:28:20,139
of an rj11 which is used for phone lines
2068
01:28:21,840 --> 01:28:22,840
and notice that this one has four pins
2069
01:28:24,420 --> 01:28:25,420
so that's two Twisted Pairs and it's
2070
01:28:27,000 --> 01:28:28,000
also much smaller than RJ45 this is
2071
01:28:29,400 --> 01:28:30,400
what's used in what's called pots plain
2072
01:28:32,340 --> 01:28:33,340
old telephone system or pstn the public
2073
01:28:36,480 --> 01:28:37,480
switched telephone Network
2074
01:28:39,480 --> 01:28:40,480
all right now moving on uh past cats uh
2075
01:28:42,900 --> 01:28:43,900
and and twisted pair let's talk about
2076
01:28:45,060 --> 01:28:46,060
coaxial cabling uh it gets its name by
2077
01:28:48,780 --> 01:28:49,780
the way from uh this is sort of a fun
2078
01:28:51,120 --> 01:28:52,120
fact common geometric access or common
2079
01:28:54,659 --> 01:28:55,659
core because the shielding and the
2080
01:28:57,120 --> 01:28:58,120
conductor share the same Center
2081
01:29:00,000 --> 01:29:01,000
or axis as the name implies in common
2082
01:29:03,420 --> 01:29:04,420
geometric access or axis
2083
01:29:06,600 --> 01:29:07,600
surrounding the single copper core is a
2084
01:29:09,719 --> 01:29:10,719
non-conducive meaning that it's not
2085
01:29:12,179 --> 01:29:13,179
going to conduct electricity insulated
2086
01:29:15,000 --> 01:29:16,000
coating which is typically uh some sort
2087
01:29:18,480 --> 01:29:19,480
of dielectric insulator separating the
2088
01:29:22,020 --> 01:29:23,020
core from the shielding
2089
01:29:24,360 --> 01:29:25,360
the next layer after that is braided
2090
01:29:26,340 --> 01:29:27,340
metal shielding and this could be either
2091
01:29:28,800 --> 01:29:29,800
copper or steel sometimes it's a mesh of
2092
01:29:31,560 --> 01:29:32,560
multiple Metals depends on the
2093
01:29:33,120 --> 01:29:34,120
manufacturer the purpose of this
2094
01:29:35,280 --> 01:29:36,280
shielding just as it was with the
2095
01:29:36,719 --> 01:29:37,719
twisted pair is to protect the cable
2096
01:29:38,699 --> 01:29:39,699
from Emi or electromagnetic interference
2097
01:29:41,100 --> 01:29:42,100
it also allows the cable to be grounded
2098
01:29:44,340 --> 01:29:45,340
and acts as sort of a drain when there
2099
01:29:47,340 --> 01:29:48,340
is noise on the line we'll talk about
2100
01:29:49,440 --> 01:29:50,440
noise in just a few minutes and also
2101
01:29:52,260 --> 01:29:53,260
ways to prevent it
2102
01:29:53,820 --> 01:29:54,820
the final layer on the coaxial cable as
2103
01:29:56,100 --> 01:29:57,100
you can see is this outer sheathing or a
2104
01:29:58,320 --> 01:29:59,320
plastic insulating jacket
2105
01:30:00,420 --> 01:30:01,420
which just sort of keeps everything
2106
01:30:02,120 --> 01:30:03,120
protected from the elements
2107
01:30:04,620 --> 01:30:05,620
now there have been several types of
2108
01:30:06,780 --> 01:30:07,780
coaxial cables used in networks over the
2109
01:30:09,360 --> 01:30:10,360
past few years uh here's a breakdown of
2110
01:30:11,639 --> 01:30:12,639
what you should be familiar with the
2111
01:30:13,920 --> 01:30:14,920
first is what's called an
2112
01:30:15,739 --> 01:30:16,739
rg58u it was used for ethernet
2113
01:30:18,719 --> 01:30:19,719
networking actually if you see old
2114
01:30:20,219 --> 01:30:21,219
network cards you'll actually see a a
2115
01:30:22,800 --> 01:30:23,800
coaxial cable on them and it has a solid
2116
01:30:25,920 --> 01:30:26,920
core and requires a 50 Ohm resistor it's
2117
01:30:29,580 --> 01:30:30,580
about five millimeters thick this is
2118
01:30:31,199 --> 01:30:32,199
different from the stuff that brings
2119
01:30:32,580 --> 01:30:33,580
cable into your home and if you remember
2120
01:30:35,699 --> 01:30:36,699
50 ohm resistor that is what was used on
2121
01:30:39,300 --> 01:30:40,300
a bust apology and that's why where we
2122
01:30:43,800 --> 01:30:44,800
actually used most of these was on a bus
2123
01:30:45,900 --> 01:30:46,900
topology now the
2124
01:30:48,380 --> 01:30:49,380
rg58au is slightly different in that
2125
01:30:51,420 --> 01:30:52,420
instead of having a solid cord it has
2126
01:30:53,219 --> 01:30:54,219
what's called a stranded core which
2127
01:30:55,080 --> 01:30:56,080
means there are multiple strands or
2128
01:30:57,540 --> 01:30:58,540
cores at its Center as opposed to one
2129
01:30:59,760 --> 01:31:00,760
solid one
2130
01:31:01,139 --> 01:31:02,139
next and this one might be a little more
2131
01:31:03,780 --> 01:31:04,780
we're going to get a little more into
2132
01:31:05,100 --> 01:31:06,100
sums that you've probably seen is What's
2133
01:31:06,900 --> 01:31:07,900
called the rg8 standard it was also used
2134
01:31:09,960 --> 01:31:10,960
for ethernet networking but it's not
2135
01:31:11,820 --> 01:31:12,820
seen very frequently today
2136
01:31:14,460 --> 01:31:15,460
um because it's typically was used for
2137
01:31:16,560 --> 01:31:17,560
backbone wiring and it's been which has
2138
01:31:19,620 --> 01:31:20,620
largely been sort of superseded by fiber
2139
01:31:22,739 --> 01:31:23,739
optics
2140
01:31:23,880 --> 01:31:24,880
finally we have rg9 uh coaxial cables
2141
01:31:27,420 --> 01:31:28,420
which are used with cable TV cable modem
2142
01:31:30,060 --> 01:31:31,060
installations and so on it's about 10
2143
01:31:32,940 --> 01:31:33,940
millimeters thick which is twice the
2144
01:31:35,040 --> 01:31:36,040
thickness of the original RG58
2145
01:31:38,040 --> 01:31:39,040
now we're getting into some others here
2146
01:31:39,540 --> 01:31:40,540
that I wouldn't worry too much about for
2147
01:31:42,719 --> 01:31:43,719
um the test but I just want to go over
2148
01:31:44,340 --> 01:31:45,340
them since we're covering these anyway
2149
01:31:45,659 --> 01:31:46,659
we have something called rg62 cabling
2150
01:31:48,480 --> 01:31:49,480
which is utilized for uh something
2151
01:31:50,340 --> 01:31:51,340
called an arcnet protocol uh networking
2152
01:31:53,040 --> 01:31:54,040
it was a lan protocol uh commonly used
2153
01:31:56,159 --> 01:31:57,159
in what was called microprocessing and
2154
01:31:59,219 --> 01:32:00,219
then we have an rg59 cable which was
2155
01:32:01,980 --> 01:32:02,980
used with low power which is used rather
2156
01:32:04,260 --> 01:32:05,260
with low power video and receivers uh
2157
01:32:06,840 --> 01:32:07,840
and it had also resistors and it was
2158
01:32:08,940 --> 01:32:09,940
about six millimeters thick the RG6
2159
01:32:12,360 --> 01:32:13,360
cabling which is greatly preferred by
2160
01:32:14,520 --> 01:32:15,520
the way over rg59
2161
01:32:17,100 --> 01:32:18,100
uh because it's more common is utilized
2162
01:32:20,580 --> 01:32:21,580
for cable television signal routing and
2163
01:32:22,920 --> 01:32:23,920
also requires
2164
01:32:24,420 --> 01:32:25,420
uh 75 ohm resistors
2165
01:32:28,500 --> 01:32:29,500
the term by the way thin net is in
2166
01:32:31,679 --> 01:32:32,679
reference to ethernet networking that
2167
01:32:34,560 --> 01:32:35,560
uses the rg58u or Au cabling these thin
2168
01:32:38,760 --> 01:32:39,760
net cables coaxial and the reason
2169
01:32:40,980 --> 01:32:41,980
they're called thin is because that thin
2170
01:32:42,659 --> 01:32:43,659
five millimeter
2171
01:32:44,219 --> 01:32:45,219
uh coaxial cable can be up to 185 meters
2172
01:32:48,600 --> 01:32:49,600
in length which is quite different from
2173
01:32:50,100 --> 01:32:51,100
the 100 meters we got with ethernet uh
2174
01:32:52,500 --> 01:32:53,500
Twisted fare
2175
01:32:54,120 --> 01:32:55,120
Network segments that utilized coaxial
2176
01:32:56,880 --> 01:32:57,880
cabling have to be terminated at the
2177
01:32:59,219 --> 01:33:00,219
ends like we've talked about to provide
2178
01:33:01,139 --> 01:33:02,139
that signal Bounce from occurring
2179
01:33:02,639 --> 01:33:03,639
they're terminated by installing that
2180
01:33:04,500 --> 01:33:05,500
resistor that matches impedance uh that
2181
01:33:07,500 --> 01:33:08,500
matches the impedance of the cable on
2182
01:33:09,179 --> 01:33:10,179
the ends so as we've mentioned some of
2183
01:33:11,219 --> 01:33:12,219
these are 50 ohms 60 Ohms on a
2184
01:33:14,460 --> 01:33:15,460
a typical bus topology Network we're
2185
01:33:17,820 --> 01:33:18,820
looking at 50 ohms
2186
01:33:21,780 --> 01:33:22,780
now here's a visual of what the most
2187
01:33:24,000 --> 01:33:25,000
common coaxial connectors are first we
2188
01:33:26,940 --> 01:33:27,940
have a picture of a BNC connector with
2189
01:33:29,820 --> 01:33:30,820
different types of resistors attached if
2190
01:33:31,860 --> 01:33:32,860
we look closely at the top connector you
2191
01:33:34,139 --> 01:33:35,139
can see the small needle at the center
2192
01:33:36,139 --> 01:33:37,139
is just slightly bigger than the 50 ohm
2193
01:33:39,540 --> 01:33:40,540
on the bottom this is important uh in
2194
01:33:42,300 --> 01:33:43,300
case you have a 75 ohm which is plugged
2195
01:33:44,520 --> 01:33:45,520
into a 50 ohm because there's going to
2196
01:33:45,960 --> 01:33:46,960
be a potential of damaging the connector
2197
01:33:49,679 --> 01:33:50,679
that's being received
2198
01:33:51,420 --> 01:33:52,420
now this next picture is a shot of a t
2199
01:33:53,340 --> 01:33:54,340
connector and a Terminator remember we
2200
01:33:55,199 --> 01:33:56,199
talked about these when we were talking
2201
01:33:56,400 --> 01:33:57,400
about bust apologies and when purchasing
2202
01:33:58,739 --> 01:33:59,739
these you want to make sure you check
2203
01:34:00,120 --> 01:34:01,120
that they're properly rated
2204
01:34:02,040 --> 01:34:03,040
because uh you know every manufacturer
2205
01:34:05,040 --> 01:34:06,040
has different color schemes and
2206
01:34:07,560 --> 01:34:08,560
different types of uh ways of
2207
01:34:10,020 --> 01:34:11,020
categorizing their terminators
2208
01:34:12,840 --> 01:34:13,840
now moving away from
2209
01:34:15,179 --> 01:34:16,179
copper cabling which is what twisted
2210
01:34:17,580 --> 01:34:18,580
pair and coaxial is let's look at fiber
2211
01:34:20,699 --> 01:34:21,699
optic cabling which is cable that uses
2212
01:34:23,540 --> 01:34:24,540
pulses of light sent down glass or
2213
01:34:26,880 --> 01:34:27,880
plastic core
2214
01:34:28,320 --> 01:34:29,320
the components in fiber optic cables
2215
01:34:30,540 --> 01:34:31,540
start out from the center working their
2216
01:34:33,000 --> 01:34:34,000
way out so the inner strengthening Rod
2217
01:34:35,760 --> 01:34:36,760
gives the cable its most most of its
2218
01:34:38,940 --> 01:34:39,940
rigidity otherwise we would just sort of
2219
01:34:40,800 --> 01:34:41,800
crack this stuff because it's very thin
2220
01:34:42,420 --> 01:34:43,420
so we have something that's going to
2221
01:34:43,860 --> 01:34:44,860
strengthen the rod and then the outside
2222
01:34:46,560 --> 01:34:47,560
of the inner strengthening Rod there is
2223
01:34:48,300 --> 01:34:49,300
filler compound in between the strands
2224
01:34:51,060 --> 01:34:52,060
of cable
2225
01:34:52,139 --> 01:34:53,139
at the center of these individual
2226
01:34:53,820 --> 01:34:54,820
strands is the fiber core which is
2227
01:34:56,400 --> 01:34:57,400
between 5 and 100 microns in a diameter
2228
01:35:00,000 --> 01:35:01,000
and I don't know if you are familiar
2229
01:35:01,560 --> 01:35:02,560
with that term Micron but that is very
2230
01:35:03,780 --> 01:35:04,780
small that's roughly
2231
01:35:06,540 --> 01:35:07,540
um slightly larger than like I think a
2232
01:35:08,580 --> 01:35:09,580
human hair so just to give you a context
2233
01:35:11,760 --> 01:35:12,760
there
2234
01:35:12,800 --> 01:35:13,800
surrounding the glass or the core which
2235
01:35:16,380 --> 01:35:17,380
might be made of plastic as well is what
2236
01:35:18,780 --> 01:35:19,780
we call Core cladding which is
2237
01:35:20,340 --> 01:35:21,340
responsible for trapping the light in
2238
01:35:22,500 --> 01:35:23,500
the core and reflecting it in a
2239
01:35:24,420 --> 01:35:25,420
particular way depending on the cable
2240
01:35:26,520 --> 01:35:27,520
mode and on the outside of the course
2241
01:35:28,620 --> 01:35:29,620
cladding there's a buffer that is color
2242
01:35:31,139 --> 01:35:32,139
coded so a technician knows which strand
2243
01:35:33,840 --> 01:35:34,840
they're working on
2244
01:35:35,639 --> 01:35:36,639
next we have strengthening fibers that
2245
01:35:37,980 --> 01:35:38,980
are typically made from very strong
2246
01:35:39,840 --> 01:35:40,840
material and finally on the outside is
2247
01:35:42,540 --> 01:35:43,540
an outer protective layer called the
2248
01:35:44,699 --> 01:35:45,699
jacket the transmission method again
2249
01:35:48,320 --> 01:35:49,320
utilizes pulses of light
2250
01:35:51,000 --> 01:35:52,000
these lights can come from LEDs or light
2251
01:35:54,480 --> 01:35:55,480
emitting diodes in cases where there is
2252
01:35:57,000 --> 01:35:58,000
a slower Network or in network with a
2253
01:35:59,820 --> 01:36:00,820
much faster connection we might even
2254
01:36:01,320 --> 01:36:02,320
have a laser
2255
01:36:03,300 --> 01:36:04,300
now there are different types of fiber
2256
01:36:05,460 --> 01:36:06,460
modes and as an as a network plus
2257
01:36:07,800 --> 01:36:08,800
administrator you need to be familiar
2258
01:36:09,780 --> 01:36:10,780
with the different methods of
2259
01:36:12,000 --> 01:36:13,000
transmission for each
2260
01:36:13,800 --> 01:36:14,800
in single mode fiber only one single
2261
01:36:17,219 --> 01:36:18,219
beam of light passes through the core
2262
01:36:19,080 --> 01:36:20,080
now a bandwidth of up to about 30
2263
01:36:21,480 --> 01:36:22,480
megahertz megahertz can be reached and
2264
01:36:24,360 --> 01:36:25,360
the signal is modulated by intensity to
2265
01:36:28,440 --> 01:36:29,440
transmit data so the intensity
2266
01:36:30,300 --> 01:36:31,300
determines the data
2267
01:36:31,920 --> 01:36:32,920
with the next thing we look at is Step
2268
01:36:34,620 --> 01:36:35,620
index multi-mode fiber the core of the
2269
01:36:37,800 --> 01:36:38,800
fiber and the clouding surrounded it
2270
01:36:39,780 --> 01:36:40,780
surrounding it rather have different
2271
01:36:41,760 --> 01:36:42,760
indices by the way if you're not
2272
01:36:43,679 --> 01:36:44,679
familiar with that word that's the
2273
01:36:44,760 --> 01:36:45,760
plural for index of refraction if that's
2274
01:36:48,239 --> 01:36:49,239
a little confusing that means that they
2275
01:36:50,520 --> 01:36:51,520
have different densities which changes
2276
01:36:53,340 --> 01:36:54,340
the speed and velocity of the light that
2277
01:36:55,500 --> 01:36:56,500
travels through the medium so when the
2278
01:36:57,420 --> 01:36:58,420
velocity changes it's called the step
2279
01:37:00,000 --> 01:37:01,000
down this is why we have step index
2280
01:37:03,659 --> 01:37:04,659
finally we have something called graded
2281
01:37:06,060 --> 01:37:07,060
index multi-mode fiber this has a core
2282
01:37:09,000 --> 01:37:10,000
glass a glass core rather that itself
2283
01:37:12,060 --> 01:37:13,060
has differences in variations in the
2284
01:37:14,280 --> 01:37:15,280
form and that allows for a large amount
2285
01:37:16,500 --> 01:37:17,500
of bandwidth that reaches up to about
2286
01:37:18,300 --> 01:37:19,300
two gigahertz
2287
01:37:20,580 --> 01:37:21,580
now the thing I want you to remember
2288
01:37:21,780 --> 01:37:22,780
most about single mode versus multi-mode
2289
01:37:24,120 --> 01:37:25,120
I wouldn't worry so much about the
2290
01:37:25,980 --> 01:37:26,980
graded index and step index but what you
2291
01:37:27,900 --> 01:37:28,900
do want to remember is that single mode
2292
01:37:29,880 --> 01:37:30,880
is good for longer distances but not as
2293
01:37:33,659 --> 01:37:34,659
high transfer speeds multi-mode is good
2294
01:37:35,880 --> 01:37:36,880
for short distances and uh higher
2295
01:37:39,360 --> 01:37:40,360
transfer speeds think about it this way
2296
01:37:40,920 --> 01:37:41,920
if I have a very large bus I'm going to
2297
01:37:44,699 --> 01:37:45,699
be able to carry more people uh in a in
2298
01:37:48,420 --> 01:37:49,420
a shorter distance if I have a sports
2299
01:37:51,000 --> 01:37:52,000
car I might be able to carry one person
2300
01:37:53,100 --> 01:37:54,100
or two people but we'll go a lot faster
2301
01:37:55,219 --> 01:37:56,219
so you can think about it that way
2302
01:37:58,679 --> 01:37:59,679
now St connectors or straight tip
2303
01:38:02,040 --> 01:38:03,040
connectors are one of the most common
2304
01:38:03,840 --> 01:38:04,840
you're going to see today they look very
2305
01:38:06,060 --> 01:38:07,060
similar to the coaxial BNC connector and
2306
01:38:09,600 --> 01:38:10,600
uh one way you can remember it is you
2307
01:38:11,639 --> 01:38:12,639
have to twist them on and I think about
2308
01:38:13,500 --> 01:38:14,500
that t for Twist the SC or otherwise
2309
01:38:16,980 --> 01:38:17,980
known as a subscriber connector is also
2310
01:38:19,380 --> 01:38:20,380
one of the most common connectors so you
2311
01:38:21,120 --> 01:38:22,120
want to recognize that one as well
2312
01:38:23,219 --> 01:38:24,219
we also have something called the LC
2313
01:38:25,020 --> 01:38:26,020
connector which looks almost like an
2314
01:38:27,420 --> 01:38:28,420
RJ45 type connector and it snaps in
2315
01:38:30,239 --> 01:38:31,239
place it's also about half the size of
2316
01:38:32,340 --> 01:38:33,340
an st and SC connector
2317
01:38:34,500 --> 01:38:35,500
I also want to show you some of the
2318
01:38:36,179 --> 01:38:37,179
other connectors that are listed on the
2319
01:38:37,500 --> 01:38:38,500
outline although I don't see them much
2320
01:38:38,820 --> 01:38:39,820
on the exam uh an mtrj or mechanical
2321
01:38:42,060 --> 01:38:43,060
transfer register Jack which is also
2322
01:38:44,880 --> 01:38:45,880
called a fiber Jack it's it's again just
2323
01:38:48,000 --> 01:38:49,000
like the same size as an RJ45 and it's
2324
01:38:50,520 --> 01:38:51,520
usually used to connect two strands of
2325
01:38:52,679 --> 01:38:53,679
fiber together
2326
01:38:54,179 --> 01:38:55,179
there's also a few other connectors uh
2327
01:38:57,120 --> 01:38:58,120
FC which is face contact uh it's used in
2328
01:39:00,719 --> 01:39:01,719
industrial environments uh it has a
2329
01:39:04,080 --> 01:39:05,080
different Center that sort of gives it
2330
01:39:06,000 --> 01:39:07,000
more strength there's also something in
2331
01:39:08,040 --> 01:39:09,040
this this you will see is called fuddy
2332
01:39:10,080 --> 01:39:11,080
or Fiber distributed data interface
2333
01:39:12,600 --> 01:39:13,600
which can also be called uh mic or SMA
2334
01:39:16,320 --> 01:39:17,320
or sub miniature assembly all these
2335
01:39:18,360 --> 01:39:19,360
different names it's an older connector
2336
01:39:20,580 --> 01:39:21,580
and it's uh one of the original
2337
01:39:23,159 --> 01:39:24,159
connectors that was used
2338
01:39:26,400 --> 01:39:27,400
now because of the different
2339
01:39:27,960 --> 01:39:28,960
technologies that are available for
2340
01:39:29,639 --> 01:39:30,639
networks today it may become necessary
2341
01:39:32,580 --> 01:39:33,580
to go from one type of medium to the
2342
01:39:34,260 --> 01:39:35,260
other in some of these cases we have to
2343
01:39:36,420 --> 01:39:37,420
utilize what's called a media converter
2344
01:39:38,639 --> 01:39:39,639
here are a couple common media
2345
01:39:40,500 --> 01:39:41,500
converters you may have come across in
2346
01:39:42,060 --> 01:39:43,060
certain networking environments
2347
01:39:43,980 --> 01:39:44,980
now there are media converters that
2348
01:39:45,900 --> 01:39:46,900
convert signals on fiber to coaxial
2349
01:39:48,360 --> 01:39:49,360
cable when you're converting
2350
01:39:50,760 --> 01:39:51,760
um
2351
01:39:52,280 --> 01:39:53,280
multi-mode fiber into ethernet in order
2352
01:39:55,560 --> 01:39:56,560
to extend the ethernet network over a
2353
01:39:57,780 --> 01:39:58,780
fiber backbone we also have similar to
2354
01:40:01,080 --> 01:40:02,080
multi-mode fiber there are also
2355
01:40:03,360 --> 01:40:04,360
converters that go from single mode
2356
01:40:04,980 --> 01:40:05,980
fiber to ethernet as well which is for
2357
01:40:07,440 --> 01:40:08,440
the same purpose generally speaking
2358
01:40:09,120 --> 01:40:10,120
we're going to see more multi-mode in
2359
01:40:10,679 --> 01:40:11,679
the backbone environment because it's a
2360
01:40:12,000 --> 01:40:13,000
shorter distance high high throughput
2361
01:40:15,260 --> 01:40:16,260
lastly there's also something a single
2362
01:40:17,639 --> 01:40:18,639
mode which converts to multi-mode fiber
2363
01:40:20,219 --> 01:40:21,219
these connectors are generally used to
2364
01:40:22,820 --> 01:40:23,820
extend the range of multi-mode signals
2365
01:40:26,880 --> 01:40:27,880
now the Tia eia which we've already
2366
01:40:29,400 --> 01:40:30,400
mentioned the organization
2367
01:40:31,040 --> 01:40:32,040
telecommunications industry Association
2368
01:40:33,060 --> 01:40:34,060
electronic Industries Association uh
2369
01:40:35,820 --> 01:40:36,820
created standards for all this cabling
2370
01:40:39,360 --> 01:40:40,360
that covers the proper implementation
2371
01:40:42,239 --> 01:40:43,239
design and maintenance to ensure that
2372
01:40:45,239 --> 01:40:46,239
there's a certain level of performance
2373
01:40:46,620 --> 01:40:47,620
that's met and that's also going to
2374
01:40:49,320 --> 01:40:50,320
ensure that if someone else comes into
2375
01:40:50,940 --> 01:40:51,940
your environment they know what they're
2376
01:40:52,440 --> 01:40:53,440
getting themselves into now there's six
2377
01:40:55,380 --> 01:40:56,380
uh the standard is comprised into six
2378
01:40:57,840 --> 01:40:58,840
different categories and it's important
2379
01:40:59,880 --> 01:41:00,880
that you actually know these for the
2380
01:41:01,320 --> 01:41:02,320
exam this by the way is called
2381
01:41:03,239 --> 01:41:04,239
structured cabling
2382
01:41:05,639 --> 01:41:06,639
so first we have something called
2383
01:41:06,840 --> 01:41:07,840
entrance facilities and this covers the
2384
01:41:09,120 --> 01:41:10,120
entrance of the Communication Service
2385
01:41:10,980 --> 01:41:11,980
into the building and this includes
2386
01:41:13,800 --> 01:41:14,800
What's called the demarcation point
2387
01:41:16,199 --> 01:41:17,199
the demarcation point is that point at
2388
01:41:19,320 --> 01:41:20,320
which the responsibility of the network
2389
01:41:21,260 --> 01:41:22,260
changes from you to your ISP or from
2390
01:41:24,780 --> 01:41:25,780
your isptu or your company it also
2391
01:41:27,300 --> 01:41:28,300
contains the backbone connections as
2392
01:41:29,040 --> 01:41:30,040
well
2393
01:41:30,420 --> 01:41:31,420
next we have the backbone wiring which
2394
01:41:33,960 --> 01:41:34,960
is the wiring connection that goes from
2395
01:41:35,699 --> 01:41:36,699
the communications closet to the
2396
01:41:37,320 --> 01:41:38,320
equipment rooms so the characteristic of
2397
01:41:40,380 --> 01:41:41,380
this wiring is going to depend on the
2398
01:41:42,600 --> 01:41:43,600
type of media chosen such as copper or
2399
01:41:45,360 --> 01:41:46,360
Fiber but nonetheless we need to make
2400
01:41:47,159 --> 01:41:48,159
sure it's it's very sturdy and also very
2401
01:41:50,580 --> 01:41:51,580
fast
2402
01:41:51,659 --> 01:41:52,659
the equipment room now uh so we've gone
2403
01:41:54,840 --> 01:41:55,840
from uh dmarc to Backbone or uh we've
2404
01:41:58,619 --> 01:41:59,619
gone from entrance facility or dmarc to
2405
01:42:00,900 --> 01:42:01,900
Backbone to equipment the equipment room
2406
01:42:03,480 --> 01:42:04,480
is the point of termination for the
2407
01:42:05,400 --> 01:42:06,400
backbone wiring it's also called the MCC
2408
01:42:07,440 --> 01:42:08,440
or the main cross contact and this can
2409
01:42:10,500 --> 01:42:11,500
also be considered what I've seen it
2410
01:42:12,659 --> 01:42:13,659
more considered on the network plus exam
2411
01:42:14,280 --> 01:42:15,280
the MDF or the main distribution frame
2412
01:42:17,760 --> 01:42:18,760
we're going to talk more about this
2413
01:42:19,320 --> 01:42:20,320
shortly
2414
01:42:21,300 --> 01:42:22,300
the next portion of structured cabling
2415
01:42:23,340 --> 01:42:24,340
are the Telecommunications closets so
2416
01:42:25,440 --> 01:42:26,440
these are contain the connection
2417
01:42:26,880 --> 01:42:27,880
equipment for any of the nearby
2418
01:42:28,800 --> 01:42:29,800
workstations as well as the connections
2419
01:42:31,199 --> 01:42:32,199
between any Communications that
2420
01:42:33,360 --> 01:42:34,360
cross-connect
2421
01:42:34,619 --> 01:42:35,619
we also have something called horizontal
2422
01:42:36,480 --> 01:42:37,480
wiring which is the cable and that goes
2423
01:42:38,460 --> 01:42:39,460
between workstations and the
2424
01:42:39,900 --> 01:42:40,900
Telecommunications closet and this is
2425
01:42:41,940 --> 01:42:42,940
typically in the wall in the ceiling
2426
01:42:45,179 --> 01:42:46,179
finally
2427
01:42:46,619 --> 01:42:47,619
we have the work area which is
2428
01:42:48,360 --> 01:42:49,360
everything coming from the wall outlet
2429
01:42:49,980 --> 01:42:50,980
to the workstation so this is the face
2430
01:42:52,320 --> 01:42:53,320
plate connectors wiring and so on so you
2431
01:42:55,320 --> 01:42:56,320
can see that we're going from the sort
2432
01:42:58,440 --> 01:42:59,440
of main point in our building that
2433
01:42:59,699 --> 01:43:00,699
entrance where the D mark happens where
2434
01:43:01,800 --> 01:43:02,800
the ISP the internet comes into our
2435
01:43:03,659 --> 01:43:04,659
building all the way down to the
2436
01:43:05,520 --> 01:43:06,520
workstation or the user
2437
01:43:07,800 --> 01:43:08,800
the Tia eia has also set out a
2438
01:43:10,500 --> 01:43:11,500
specification of standards that line out
2439
01:43:12,840 --> 01:43:13,840
minimum performance levels for Network
2440
01:43:14,940 --> 01:43:15,940
media in uh commercial environments now
2441
01:43:18,239 --> 01:43:19,239
these standards are 568 a b and c we saw
2442
01:43:21,960 --> 01:43:22,960
earlier the t568 A and B which were the
2443
01:43:24,960 --> 01:43:25,960
standards for uh cabling colored Twisted
2444
01:43:29,100 --> 01:43:30,100
Pairs and how they should be arranged
2445
01:43:30,840 --> 01:43:31,840
and terminated but there are also some
2446
01:43:33,060 --> 01:43:34,060
other specific attributes that you need
2447
01:43:35,639 --> 01:43:36,639
to be aware of
2448
01:43:36,840 --> 01:43:37,840
the 568a specification is an older
2449
01:43:39,659 --> 01:43:40,659
standard it's governed uh it governed
2450
01:43:42,239 --> 01:43:43,239
data voice video and commercial
2451
01:43:44,400 --> 01:43:45,400
buildings and it's basically been
2452
01:43:46,739 --> 01:43:47,739
outdated and superseded nowadays by 568a
2453
01:43:49,920 --> 01:43:50,920
sorry B and C standards the B
2454
01:43:52,980 --> 01:43:53,980
specification now is an earlier standard
2455
01:43:55,320 --> 01:43:56,320
still in use quite frequently that
2456
01:43:57,659 --> 01:43:58,659
defines minimum performance levels for
2457
01:44:00,179 --> 01:44:01,179
cabling including twisted pair
2458
01:44:02,219 --> 01:44:03,219
performance minimums uh shielded Twisted
2459
01:44:05,639 --> 01:44:06,639
paramums fiber optic standards and Etc
2460
01:44:09,480 --> 01:44:10,480
portions of this are now Obsolete and
2461
01:44:11,820 --> 01:44:12,820
have been replaced by 568c the 568c
2462
01:44:16,199 --> 01:44:17,199
standard
2463
01:44:17,460 --> 01:44:18,460
which is the current specification
2464
01:44:19,080 --> 01:44:20,080
that's set out designates minimums for
2465
01:44:21,659 --> 01:44:22,659
optimizing Network media performance in
2466
01:44:24,239 --> 01:44:25,239
commercial buildings currently it
2467
01:44:26,639 --> 01:44:27,639
specifies cat 6A as the media type that
2468
01:44:29,760 --> 01:44:30,760
is recommended so again the 568 A and B
2469
01:44:33,179 --> 01:44:34,179
the T5 to 68 A and B that we saw earlier
2470
01:44:35,340 --> 01:44:36,340
those are how everything is cabled those
2471
01:44:37,739 --> 01:44:38,739
fall under the umbrella of the more
2472
01:44:39,900 --> 01:44:40,900
General 568 a b and c standards which
2473
01:44:43,440 --> 01:44:44,440
speak more to Performance
2474
01:44:45,659 --> 01:44:46,659
now while the Tia and the eia have
2475
01:44:47,820 --> 01:44:48,820
established uh standards for structured
2476
01:44:50,520 --> 01:44:51,520
cabling
2477
01:44:51,600 --> 01:44:52,600
premise wiring uh
2478
01:44:54,600 --> 01:44:55,600
the terms that we're going to use are
2479
01:44:56,580 --> 01:44:57,580
industry-wide so although there might be
2480
01:45:00,300 --> 01:45:01,300
these standards the terms you're going
2481
01:45:03,000 --> 01:45:04,000
to see over and over again
2482
01:45:05,340 --> 01:45:06,340
hierarchical cabling is recognized and
2483
01:45:08,760 --> 01:45:09,760
used which is what we're talking about
2484
01:45:10,860 --> 01:45:11,860
when we talk about premise wiring
2485
01:45:12,420 --> 01:45:13,420
everywhere
2486
01:45:14,880 --> 01:45:15,880
it's a telecommunications design
2487
01:45:17,760 --> 01:45:18,760
tradition that basically allows for main
2488
01:45:21,000 --> 01:45:22,000
cross connects or MCCS to be connected
2489
01:45:23,699 --> 01:45:24,699
to what are called iccs or intermediate
2490
01:45:26,340 --> 01:45:27,340
cross connects in a star topology with
2491
01:45:30,000 --> 01:45:31,000
horizontal cross connects in most cases
2492
01:45:33,060 --> 01:45:34,060
you're probably going to see the terms
2493
01:45:34,619 --> 01:45:35,619
wiring closet MDF or main distribution
2494
01:45:38,520 --> 01:45:39,520
frame and IDF or intermediate
2495
01:45:41,639 --> 01:45:42,639
distribution frame instead of MCC and
2496
01:45:44,219 --> 01:45:45,219
ICC however they're both used
2497
01:45:46,679 --> 01:45:47,679
interchangeably so I just want to take a
2498
01:45:48,960 --> 01:45:49,960
look at some of the components that make
2499
01:45:50,639 --> 01:45:51,639
up this premise wiring right now
2500
01:45:53,760 --> 01:45:54,760
the patch panel is the connection point
2501
01:45:56,400 --> 01:45:57,400
for drop cables and patch cables they're
2502
01:45:59,639 --> 01:46:00,639
connected to the patch panel via the
2503
01:46:02,100 --> 01:46:03,100
RJ45 connectors that we saw with twisted
2504
01:46:04,440 --> 01:46:05,440
pair now you might find a patch cable
2505
01:46:06,840 --> 01:46:07,840
with a single row of connections or one
2506
01:46:09,780 --> 01:46:10,780
with a dozen or more rows now a drop
2507
01:46:12,300 --> 01:46:13,300
cable what I just mentioned is the cable
2508
01:46:14,219 --> 01:46:15,219
that goes from the workstation and the
2509
01:46:16,440 --> 01:46:17,440
network devices to the wall
2510
01:46:18,780 --> 01:46:19,780
a patch cable is a cable that is
2511
01:46:21,659 --> 01:46:22,659
connected to the patch panel and
2512
01:46:23,699 --> 01:46:24,699
connects two drop cables this cable
2513
01:46:26,639 --> 01:46:27,639
might be either a normal straight
2514
01:46:28,679 --> 01:46:29,679
through cable or a crossover cable which
2515
01:46:31,320 --> 01:46:32,320
is something I mentioned earlier that
2516
01:46:33,000 --> 01:46:34,000
crossover cable has one end that has the
2517
01:46:35,420 --> 01:46:36,420
568a wiring and the other end that has
2518
01:46:37,739 --> 01:46:38,739
568 B wiring this is in order to connect
2519
01:46:41,159 --> 01:46:42,159
two like devices such as computers or
2520
01:46:44,639 --> 01:46:45,639
switches directly to each other remember
2521
01:46:46,980 --> 01:46:47,980
the pin out on these is different
2522
01:46:48,540 --> 01:46:49,540
because the one and two pins are
2523
01:46:50,639 --> 01:46:51,639
switched on one end with the three and
2524
01:46:52,739 --> 01:46:53,739
six pins so this allows data to go
2525
01:46:54,780 --> 01:46:55,780
directly between two devices a lot of
2526
01:46:57,540 --> 01:46:58,540
devices nowadays however don't require
2527
01:46:59,520 --> 01:47:00,520
the crossover cable uh because they have
2528
01:47:02,159 --> 01:47:03,159
an auto sort of sensing feature within
2529
01:47:03,960 --> 01:47:04,960
them now a patch panel and patch cables
2530
01:47:06,840 --> 01:47:07,840
are located in wiring closets
2531
01:47:10,440 --> 01:47:11,440
the IDF is the communications connection
2532
01:47:13,619 --> 01:47:14,619
point or cable rack that connects all
2533
01:47:16,260 --> 01:47:17,260
the workstations to the MDF or the main
2534
01:47:19,980 --> 01:47:20,980
distribution frame the main distribution
2535
01:47:22,800 --> 01:47:23,800
frame MDF is the main connection point
2536
01:47:25,739 --> 01:47:26,739
or cable rack that distributes cables
2537
01:47:28,320 --> 01:47:29,320
from itself to all the other idfs now
2538
01:47:31,619 --> 01:47:32,619
there's only going to be one MDF but
2539
01:47:33,840 --> 01:47:34,840
there can be many idfs the wiring closet
2540
01:47:37,020 --> 01:47:38,020
is a room where the patch panels are
2541
01:47:39,420 --> 01:47:40,420
installed and the wiring runs through it
2542
01:47:41,520 --> 01:47:42,520
too
2543
01:47:42,480 --> 01:47:43,480
so here we have a building where we have
2544
01:47:43,980 --> 01:47:44,980
an MDF on the bottom floor and an IDF on
2545
01:47:46,860 --> 01:47:47,860
each of the floors above the connections
2546
01:47:49,199 --> 01:47:50,199
going from the idfs through the walls go
2547
01:47:51,900 --> 01:47:52,900
to the workstations then there is a
2548
01:47:54,480 --> 01:47:55,480
connection that's typically much faster
2549
01:47:56,159 --> 01:47:57,159
than the rest of the network that goes
2550
01:47:57,659 --> 01:47:58,659
between the idfs and the MDF
2551
01:48:00,300 --> 01:48:01,300
when installing Cable in a building
2552
01:48:02,699 --> 01:48:03,699
there are fire code requirements that
2553
01:48:05,100 --> 01:48:06,100
have to be met
2554
01:48:06,239 --> 01:48:07,239
specifically when you're running cable
2555
01:48:08,460 --> 01:48:09,460
and air handling spaces which are like
2556
01:48:10,739 --> 01:48:11,739
under floors and in walls most of the
2557
01:48:14,219 --> 01:48:15,219
fire codes require a specific cable
2558
01:48:17,219 --> 01:48:18,219
PVC cabling which is the typically
2559
01:48:19,380 --> 01:48:20,380
standard network cable that's fairly
2560
01:48:21,960 --> 01:48:22,960
inexpensive and easy to work with allows
2561
01:48:24,619 --> 01:48:25,619
allows fire to travel through the cable
2562
01:48:27,000 --> 01:48:28,000
if it berms and then it releases these
2563
01:48:30,300 --> 01:48:31,300
poisonous and noxious fumes so as a
2564
01:48:33,659 --> 01:48:34,659
result plenum grade cabling which is
2565
01:48:37,199 --> 01:48:38,199
part of the uh plenum or a plenum space
2566
01:48:40,739 --> 01:48:41,739
is part of a building that is used for
2567
01:48:43,080 --> 01:48:44,080
air circulation and HVAC systems and so
2568
01:48:45,780 --> 01:48:46,780
on by providing Pathways either that are
2569
01:48:48,360 --> 01:48:49,360
heated conditioned or have return
2570
01:48:51,060 --> 01:48:52,060
airflows
2571
01:48:52,320 --> 01:48:53,320
space between the structural floor and
2572
01:48:54,360 --> 01:48:55,360
the dropped ceiling or under a raised
2573
01:48:56,340 --> 01:48:57,340
floor is what's called plenum so we have
2574
01:48:59,340 --> 01:49:00,340
some special cabling called plenum
2575
01:49:01,320 --> 01:49:02,320
cabling this is jacketing that's wrapped
2576
01:49:03,480 --> 01:49:04,480
around the wires very tightly and it
2577
01:49:05,580 --> 01:49:06,580
prevents fire from moving through it
2578
01:49:07,020 --> 01:49:08,020
therefore it's not going to put off
2579
01:49:09,480 --> 01:49:10,480
those noxious and poisonous fumes it
2580
01:49:12,060 --> 01:49:13,060
also makes the cable a lot more
2581
01:49:13,320 --> 01:49:14,320
expensive and it can be a lot difficult
2582
01:49:15,540 --> 01:49:16,540
a lot more difficult to work with at
2583
01:49:17,340 --> 01:49:18,340
times however it is required by fire
2584
01:49:19,560 --> 01:49:20,560
code that if you're running cabling in
2585
01:49:21,119 --> 01:49:22,119
between these spaces where there is no
2586
01:49:23,280 --> 01:49:24,280
sort of
2587
01:49:25,320 --> 01:49:26,320
sprinkler system to put out the fire
2588
01:49:27,300 --> 01:49:28,300
that you use plenum grade cabling that's
2589
01:49:29,520 --> 01:49:30,520
important all right so now let's go over
2590
01:49:31,500 --> 01:49:32,500
what we learned first we defined Network
2591
01:49:33,960 --> 01:49:34,960
media as well as what bounded media is
2592
01:49:37,500 --> 01:49:38,500
we're going to talk about unbounded
2593
01:49:38,880 --> 01:49:39,880
media a little bit later we also
2594
01:49:40,679 --> 01:49:41,679
describe the different types of copper
2595
01:49:42,300 --> 01:49:43,300
media including the different types of
2596
01:49:44,639 --> 01:49:45,639
Stan shielded twisted pair and
2597
01:49:47,400 --> 01:49:48,400
unshielded twisted pair and the
2598
01:49:49,320 --> 01:49:50,320
difference between those remember
2599
01:49:50,340 --> 01:49:51,340
shielded it protects from Emi unshielded
2600
01:49:53,520 --> 01:49:54,520
does not and we discussed a few of the
2601
01:49:55,320 --> 01:49:56,320
standards that are set by the Tia eia
2602
01:49:57,500 --> 01:49:58,500
including 568 a b and c and remember
2603
01:50:01,199 --> 01:50:02,199
that's we also have the 568 A and B
2604
01:50:04,159 --> 01:50:05,159
wiring requirements which fall under
2605
01:50:06,360 --> 01:50:07,360
these we also looked at the different
2606
01:50:08,280 --> 01:50:09,280
connector types not only for the twisted
2607
01:50:10,739 --> 01:50:11,739
pair which is that RJ45 but for coaxial
2608
01:50:13,619 --> 01:50:14,619
like the BNC and fiber such as St or SC
2609
01:50:16,980 --> 01:50:17,980
and we looked at structured cabling and
2610
01:50:20,400 --> 01:50:21,400
premise wiring where we also talked
2611
01:50:22,380 --> 01:50:23,380
about the differences and this is
2612
01:50:23,820 --> 01:50:24,820
important between PVC cabling
2613
01:50:26,400 --> 01:50:27,400
and plenum grade cabling
2614
01:50:31,190 --> 01:50:32,190
[Music]
2615
01:50:47,520 --> 01:50:48,520
welcome to module 2 lesson 1A straight
2616
01:50:50,699 --> 01:50:51,699
through crossover and rollover cables
2617
01:50:53,040 --> 01:50:54,040
we've actually covered some of this
2618
01:50:55,260 --> 01:50:56,260
already in earlier lessons but what I've
2619
01:50:58,139 --> 01:50:59,139
done is added upgrades for the new exam
2620
01:51:01,260 --> 01:51:02,260
syllabus so consider some of it a
2621
01:51:03,659 --> 01:51:04,659
refresher and um some of the new
2622
01:51:06,300 --> 01:51:07,300
material
2623
01:51:07,440 --> 01:51:08,440
so we're still under Network Hardware
2624
01:51:09,300 --> 01:51:10,300
media bounded Network media
2625
01:51:12,719 --> 01:51:13,719
a few of the objectives
2626
01:51:14,880 --> 01:51:15,880
looking at modular connectors the
2627
01:51:18,500 --> 01:51:19,500
t568a and B wiring schemes MDI and mdix
2628
01:51:23,480 --> 01:51:24,480
straight through cables
2629
01:51:26,159 --> 01:51:27,159
crossover cable and then Auto
2630
01:51:29,460 --> 01:51:30,460
mdix which is a bit of a mouthful
2631
01:51:33,360 --> 01:51:34,360
and uh another cable you'll be using
2632
01:51:35,940 --> 01:51:36,940
regularly as a network engineer which is
2633
01:51:37,920 --> 01:51:38,920
a rollover cable
2634
01:51:39,900 --> 01:51:40,900
they've got different names actually
2635
01:51:41,280 --> 01:51:42,280
they can be called console cables if
2636
01:51:43,619 --> 01:51:44,619
you're working in the Cisco side of
2637
01:51:46,739 --> 01:51:47,739
things we tend to call them rollover
2638
01:51:48,659 --> 01:51:49,659
cables or flat cables
2639
01:51:51,239 --> 01:51:52,239
but I'm sure you'll find out wherever
2640
01:51:52,980 --> 01:51:53,980
you end up working what uh
2641
01:51:56,520 --> 01:51:57,520
what they're called so modular
2642
01:51:58,560 --> 01:51:59,560
connectors
2643
01:51:59,699 --> 01:52:00,699
a type of electrical Electric electrical
2644
01:52:02,100 --> 01:52:03,100
connector that's commonly used in the
2645
01:52:04,199 --> 01:52:05,199
following systems we'll see these in a
2646
01:52:07,500 --> 01:52:08,500
telephone systems data networks which is
2647
01:52:10,199 --> 01:52:11,199
what we're more interested in as Network
2648
01:52:11,699 --> 01:52:12,699
engineers
2649
01:52:13,199 --> 01:52:14,199
low speed serial connections can also
2650
01:52:15,480 --> 01:52:16,480
use them
2651
01:52:16,739 --> 01:52:17,739
and now by the following names RJ which
2652
01:52:19,560 --> 01:52:20,560
is short for registered Jack
2653
01:52:22,560 --> 01:52:23,560
modular phone jack stroke plug
2654
01:52:25,920 --> 01:52:26,920
uh Western Jack stroke plug
2655
01:52:29,820 --> 01:52:30,820
just go back there you can see the port
2656
01:52:32,179 --> 01:52:33,179
which is the interface that the module
2657
01:52:35,580 --> 01:52:36,580
modular connector goes into and then the
2658
01:52:38,280 --> 01:52:39,280
physical layer which will specify um a
2659
01:52:40,560 --> 01:52:41,560
whole bunch of things like the voltage
2660
01:52:42,480 --> 01:52:43,480
on the wire and how many wires and or
2661
01:52:45,119 --> 01:52:46,119
teach wire is used for some of them are
2662
01:52:47,699 --> 01:52:48,699
unused and um as the connections get uh
2663
01:52:50,940 --> 01:52:51,940
quicker
2664
01:52:52,020 --> 01:52:53,020
and the engine is worked out how to use
2665
01:52:54,000 --> 01:52:55,000
spare air wires to increase speed which
2666
01:52:57,119 --> 01:52:58,119
you'll see in a bit the male modular
2667
01:52:59,340 --> 01:53:00,340
connector is known as a plug
2668
01:53:02,159 --> 01:53:03,159
uh basically the cable
2669
01:53:04,860 --> 01:53:05,860
um is terminated inside here normally
2670
01:53:07,440 --> 01:53:08,440
you do buy these however
2671
01:53:09,719 --> 01:53:10,719
um if you become a cabling engineer
2672
01:53:12,659 --> 01:53:13,659
you can have your own tools to make your
2673
01:53:15,239 --> 01:53:16,239
own network cables I did it for a while
2674
01:53:17,040 --> 01:53:18,040
I can't say it was particularly
2675
01:53:19,560 --> 01:53:20,560
um a lot of fun
2676
01:53:21,060 --> 01:53:22,060
but it did pay pretty well
2677
01:53:22,920 --> 01:53:23,920
a female modular connector is known as a
2678
01:53:25,920 --> 01:53:26,920
Jack or socket
2679
01:53:28,320 --> 01:53:29,320
used on fixed locations
2680
01:53:31,320 --> 01:53:32,320
um such as on equipment
2681
01:53:34,460 --> 01:53:35,460
uh example of the module modular
2682
01:53:36,960 --> 01:53:37,960
connector is the 8 p8c connector uh I
2683
01:53:40,739 --> 01:53:41,739
think Josh may have referred to that
2684
01:53:42,239 --> 01:53:43,239
elsewhere
2685
01:53:44,400 --> 01:53:45,400
but here we go here's a an image of one
2686
01:53:47,820 --> 01:53:48,820
uh using ethernet computer network that
2687
01:53:50,340 --> 01:53:51,340
uses the twisted pair cables for
2688
01:53:53,520 --> 01:53:54,520
connection which is pretty much every
2689
01:53:54,960 --> 01:53:55,960
Network now unless you went into some
2690
01:53:57,300 --> 01:53:58,300
old basement
2691
01:53:58,800 --> 01:53:59,800
um or some odd unit somewhere
2692
01:54:02,100 --> 01:54:03,100
commonly referred to as RJ45 it
2693
01:54:04,920 --> 01:54:05,920
resembles the connectors you'd have on
2694
01:54:07,619 --> 01:54:08,619
many phones we have at home which uses
2695
01:54:09,900 --> 01:54:10,900
an RJ 11
2696
01:54:11,840 --> 01:54:12,840
telephone cables But as time goes on
2697
01:54:15,060 --> 01:54:16,060
these will all be changing and I think a
2698
01:54:16,619 --> 01:54:17,619
lot of people don't really even use
2699
01:54:18,540 --> 01:54:19,540
their home phones much anymore
2700
01:54:21,360 --> 01:54:22,360
uh has nothing to do with the actual
2701
01:54:23,520 --> 01:54:24,520
RJ45 standard
2702
01:54:26,639 --> 01:54:27,639
looking at the um t568 A and B wiring
2703
01:54:30,840 --> 01:54:31,840
schemes
2704
01:54:32,100 --> 01:54:33,100
these are the specifications in more
2705
01:54:34,739 --> 01:54:35,739
detail it's a four pair 100 ohm and
2706
01:54:37,920 --> 01:54:38,920
shielded twisted their cable
2707
01:54:40,139 --> 01:54:41,139
and
2708
01:54:41,400 --> 01:54:42,400
usually terminated into an a position
2709
01:54:43,800 --> 01:54:44,800
modular Jack
2710
01:54:45,900 --> 01:54:46,900
now there's two wiring schemes five six
2711
01:54:48,480 --> 01:54:49,480
eight a five six eight B
2712
01:54:50,820 --> 01:54:51,820
this defines the pin out and the Order
2713
01:54:52,739 --> 01:54:53,739
of the connections and this is very
2714
01:54:54,719 --> 01:54:55,719
important we can't just connect any
2715
01:54:56,520 --> 01:54:57,520
color cable
2716
01:54:58,860 --> 01:54:59,860
um inside and attach them to any of the
2717
01:55:01,080 --> 01:55:02,080
pins on them on the end there has to be
2718
01:55:04,020 --> 01:55:05,020
a specific order depending on what we're
2719
01:55:06,840 --> 01:55:07,840
trying to achieve
2720
01:55:08,040 --> 01:55:09,040
you can obviously buy the cable it comes
2721
01:55:10,920 --> 01:55:11,920
off um big rolls it could be a few
2722
01:55:14,400 --> 01:55:15,400
hundred meters long and it's twisted
2723
01:55:16,920 --> 01:55:17,920
into one two three four pairs there
2724
01:55:20,639 --> 01:55:21,639
and they can be just untwisted slightly
2725
01:55:23,100 --> 01:55:24,100
at the end and then the you can see the
2726
01:55:25,020 --> 01:55:26,020
blue shielding there is normally
2727
01:55:27,179 --> 01:55:28,179
inserted just enough so it um catches
2728
01:55:30,659 --> 01:55:31,659
inside the Jack and then you've got a
2729
01:55:32,159 --> 01:55:33,159
crimping tool which squeezes it onto the
2730
01:55:34,860 --> 01:55:35,860
plastic connector on the end
2731
01:55:38,699 --> 01:55:39,699
now we as I said we need to know which
2732
01:55:41,040 --> 01:55:42,040
wire of the cable connects to which pin
2733
01:55:42,900 --> 01:55:43,900
and which wiring standards we use the um
2734
01:55:46,460 --> 01:55:47,460
t568 A and B standards govern the
2735
01:55:49,619 --> 01:55:50,619
assignments of the wires so it says
2736
01:55:51,179 --> 01:55:52,179
which wires go where
2737
01:55:53,400 --> 01:55:54,400
now here's a graphic you can see and the
2738
01:55:57,119 --> 01:55:58,119
pairs are put together with similar
2739
01:55:59,639 --> 01:56:00,639
colors and then the specific colors
2740
01:56:02,400 --> 01:56:03,400
allocated for each pin going from one to
2741
01:56:05,280 --> 01:56:06,280
eight so
2742
01:56:07,020 --> 01:56:08,020
um white and green green white and
2743
01:56:08,760 --> 01:56:09,760
orange
2744
01:56:10,440 --> 01:56:11,440
and blue white and blue orange
2745
01:56:14,520 --> 01:56:15,520
white and brown and then Brown
2746
01:56:17,880 --> 01:56:18,880
you can see different pins on the right
2747
01:56:19,500 --> 01:56:20,500
because we've got a different standard
2748
01:56:21,480 --> 01:56:22,480
yes and I've put on here which one's
2749
01:56:23,820 --> 01:56:24,820
which
2750
01:56:24,840 --> 01:56:25,840
so there's an interchange of green and
2751
01:56:26,880 --> 01:56:27,880
orange wire pairs between the two
2752
01:56:28,920 --> 01:56:29,920
different standards
2753
01:56:32,639 --> 01:56:33,639
now I'll come to horizontal cables in a
2754
01:56:35,340 --> 01:56:36,340
minute because
2755
01:56:36,040 --> 01:56:37,040
[Music]
2756
01:56:36,420 --> 01:56:37,420
um
2757
01:56:37,199 --> 01:56:38,199
you don't actually hear this
2758
01:56:40,860 --> 01:56:41,860
um term very often in Internet working
2759
01:56:43,560 --> 01:56:44,560
and I hadn't heard of it for um until I
2760
01:56:46,739 --> 01:56:47,739
come to put all the information together
2761
01:56:48,659 --> 01:56:49,659
for the presentation but it's a
2762
01:56:51,360 --> 01:56:52,360
recognized name even though it isn't
2763
01:56:53,040 --> 01:56:54,040
used very often
2764
01:56:55,199 --> 01:56:56,199
so the um 568b pin app became model used
2765
01:56:58,980 --> 01:56:59,980
because it matched the older at T their
2766
01:57:01,679 --> 01:57:02,679
pin outs and you can see the standard
2767
01:57:03,239 --> 01:57:04,239
there widely used a new TP Cable in at
2768
01:57:06,480 --> 01:57:07,480
the time and the infrastructure
2769
01:57:09,320 --> 01:57:10,320
regulations and numbers were published
2770
01:57:13,380 --> 01:57:14,380
just for your information you can
2771
01:57:15,060 --> 01:57:16,060
research in your own time if you want
2772
01:57:16,739 --> 01:57:17,739
but you can see a horizontal cabling in
2773
01:57:19,080 --> 01:57:20,080
action here generally it's the cabling
2774
01:57:21,420 --> 01:57:22,420
that runs between all the user devices
2775
01:57:23,400 --> 01:57:24,400
the patch panels and the network
2776
01:57:25,440 --> 01:57:26,440
switches now however you've got your
2777
01:57:27,780 --> 01:57:28,780
network designs you'll normally group
2778
01:57:29,219 --> 01:57:30,219
the switches together with what's known
2779
01:57:30,900 --> 01:57:31,900
as backbone cabling
2780
01:57:33,080 --> 01:57:34,080
so that's it in um image format there's
2781
01:57:37,560 --> 01:57:38,560
a definition which I got from Wikipedia
2782
01:57:40,679 --> 01:57:41,679
it can be the inside wiring or plenum
2783
01:57:43,380 --> 01:57:44,380
Cable in connects your telecoms rooms to
2784
01:57:45,659 --> 01:57:46,659
individual Outlets or work areas on the
2785
01:57:47,699 --> 01:57:48,699
floor usually Through the Wire ways so
2786
01:57:50,159 --> 01:57:51,159
this is the part of the cabling that you
2787
01:57:52,260 --> 01:57:53,260
would normally
2788
01:57:53,520 --> 01:57:54,520
um be concerned with as a network
2789
01:57:54,719 --> 01:57:55,719
engineer and then um the core Cable in
2790
01:57:57,659 --> 01:57:58,659
the backbone cabling May well be done by
2791
01:58:00,659 --> 01:58:01,659
a cabling company it's not something
2792
01:58:02,760 --> 01:58:03,760
that you would normally get involved in
2793
01:58:04,739 --> 01:58:05,739
again it depends every networks a bit
2794
01:58:07,380 --> 01:58:08,380
different
2795
01:58:08,520 --> 01:58:09,520
and moving on to MDI and MDI X
2796
01:58:12,360 --> 01:58:13,360
and
2797
01:58:13,860 --> 01:58:14,860
devices on ethernet networks use two
2798
01:58:16,199 --> 01:58:17,199
types of Hardware interfaces which I've
2799
01:58:18,840 --> 01:58:19,840
already mentioned here the MDI it all
2800
01:58:21,480 --> 01:58:22,480
stands for media and medium dependent
2801
01:58:23,400 --> 01:58:24,400
interface
2802
01:58:24,599 --> 01:58:25,599
so Hardware interface that establishes
2803
01:58:26,520 --> 01:58:27,520
the direct physical and electrical
2804
01:58:28,800 --> 01:58:29,800
connection with a UTP cable this is the
2805
01:58:32,460 --> 01:58:33,460
traditional port on the back of a
2806
01:58:33,840 --> 01:58:34,840
computer's network interface card
2807
01:58:39,179 --> 01:58:40,179
an MDR device is a device with an MDI
2808
01:58:42,000 --> 01:58:43,000
Port which kind of goes without saying I
2809
01:58:44,219 --> 01:58:45,219
guess a computer or laptop
2810
01:58:47,639 --> 01:58:48,639
um and this is a reference for
2811
01:58:49,020 --> 01:58:50,020
specifications really I mean in all the
2812
01:58:51,239 --> 01:58:52,239
years of networking I've never referred
2813
01:58:52,800 --> 01:58:53,800
to a device as an MDI device
2814
01:58:55,739 --> 01:58:56,739
and tend to discuss it more when we were
2815
01:58:58,199 --> 01:58:59,199
using Hobs
2816
01:59:00,659 --> 01:59:01,659
um in the earlier days of networking the
2817
01:59:03,420 --> 01:59:04,420
mdix stands for um the MDI but with a
2818
01:59:06,719 --> 01:59:07,719
crossover
2819
01:59:07,980 --> 01:59:08,980
this is a crossover of the
2820
01:59:10,500 --> 01:59:11,500
um medium dependent interface I'll show
2821
01:59:12,659 --> 01:59:13,659
it up an image actually in a moment the
2822
01:59:15,360 --> 01:59:16,360
thoughts of the devices that provide
2823
01:59:16,920 --> 01:59:17,920
connectivity such as a switcher hover
2824
01:59:18,960 --> 01:59:19,960
setup as a MDI with the crossover
2825
01:59:25,080 --> 01:59:26,080
foreign
2826
01:59:26,219 --> 01:59:27,219
so examples of the devices are switches
2827
01:59:29,580 --> 01:59:30,580
or routers and I'll put in an image here
2828
01:59:32,699 --> 01:59:33,699
to give you more
2829
01:59:35,280 --> 01:59:36,280
um
2830
01:59:36,719 --> 01:59:37,719
a frame of reference you can see here
2831
01:59:39,179 --> 01:59:40,179
it's the front of an old fashioned
2832
01:59:42,119 --> 01:59:43,119
Netgear maybe they don't even sell him
2833
01:59:43,920 --> 01:59:44,920
anymore
2834
01:59:45,599 --> 01:59:46,599
um Hub and you can see to the right
2835
01:59:47,760 --> 01:59:48,760
there's a little black switch with a
2836
01:59:49,560 --> 01:59:50,560
little line that connects to the number
2837
01:59:51,179 --> 01:59:52,179
four
2838
01:59:52,380 --> 01:59:53,380
now however you press that button it
2839
01:59:54,719 --> 01:59:55,719
will act as an MDI or an mdix interface
2840
01:59:58,920 --> 01:59:59,920
now if you wanted to connect that number
2841
02:00:01,860 --> 02:00:02,860
four port to a PC
2842
02:00:03,900 --> 02:00:04,900
you would leave it running in normal
2843
02:00:07,380 --> 02:00:08,380
um mode you might be able to see the
2844
02:00:09,119 --> 02:00:10,119
actual word normal it's a bit blurry
2845
02:00:10,619 --> 02:00:11,619
this image so this is MDI and they're
2846
02:00:13,920 --> 02:00:14,920
put normal because um You probably
2847
02:00:15,719 --> 02:00:16,719
wouldn't be a network engineer using it
2848
02:00:17,340 --> 02:00:18,340
at home or small office
2849
02:00:20,460 --> 02:00:21,460
um the mdix they've designated as an
2850
02:00:23,880 --> 02:00:24,880
Uplink that means you would connect it
2851
02:00:25,560 --> 02:00:26,560
to another hub
2852
02:00:26,940 --> 02:00:27,940
and so the it would change the way it
2853
02:00:29,520 --> 02:00:30,520
connect and communicates using the
2854
02:00:31,679 --> 02:00:32,679
different pin outs and it would act as
2855
02:00:34,139 --> 02:00:35,139
if um you you're using a crossover cable
2856
02:00:36,480 --> 02:00:37,480
which we'll come to later
2857
02:00:42,840 --> 02:00:43,840
so this is basically what I've said it's
2858
02:00:44,760 --> 02:00:45,760
going to um using the button you would
2859
02:00:47,880 --> 02:00:48,880
um designate whether it's going to act
2860
02:00:49,199 --> 02:00:50,199
as an MDI or an MDI X interface
2861
02:00:54,900 --> 02:00:55,900
um this all basically changes how we use
2862
02:00:57,000 --> 02:00:58,000
our transmit which is designated as TX
2863
02:00:59,659 --> 02:01:00,659
and I'll receive which is designated as
2864
02:01:02,400 --> 02:01:03,400
RX on the different wires and that's
2865
02:01:04,920 --> 02:01:05,920
saying what that setting would do
2866
02:01:07,380 --> 02:01:08,380
straight through cable the easiest way
2867
02:01:09,360 --> 02:01:10,360
to think about straight through cable is
2868
02:01:12,300 --> 02:01:13,300
um using dissimilar devices for example
2869
02:01:14,400 --> 02:01:15,400
a um computer to a switch port a router
2870
02:01:19,320 --> 02:01:20,320
to a switch
2871
02:01:23,099 --> 02:01:24,099
and here's some examples also known as a
2872
02:01:25,440 --> 02:01:26,440
patch cable in case anyone asks you to
2873
02:01:27,540 --> 02:01:28,540
check a patch cable or get get them a
2874
02:01:30,239 --> 02:01:31,239
patch cable
2875
02:01:32,219 --> 02:01:33,219
I've mentioned UTP UTP cables they're
2876
02:01:35,159 --> 02:01:36,159
used in the modern ethernet Networks
2877
02:01:37,920 --> 02:01:38,920
and you can't directly connect unless
2878
02:01:40,380 --> 02:01:41,380
you stay in the obvious I think you
2879
02:01:41,699 --> 02:01:42,699
can't directly connect these wires to a
2880
02:01:43,380 --> 02:01:44,380
computer's network interface card
2881
02:01:46,920 --> 02:01:47,920
um if you want to be picky I suppose you
2882
02:01:48,659 --> 02:01:49,659
could if you had a soldering iron and
2883
02:01:51,000 --> 02:01:52,000
individually sold at each wire but that
2884
02:01:53,280 --> 02:01:54,280
would just be a little bit of a
2885
02:01:55,040 --> 02:01:56,040
desperation not somebody that doesn't
2886
02:01:57,540 --> 02:01:58,540
really need to unplug
2887
02:01:59,880 --> 02:02:00,880
so both ends are terminated with the
2888
02:02:01,800 --> 02:02:02,800
8phc connectors
2889
02:02:04,380 --> 02:02:05,380
and you can see the two wiring types
2890
02:02:06,239 --> 02:02:07,239
here using that AP AC connectors
2891
02:02:08,940 --> 02:02:09,940
now the pins and the wire assignments
2892
02:02:10,800 --> 02:02:11,800
are the same on both ends so we know
2893
02:02:13,199 --> 02:02:14,199
this is a straight through cable or a
2894
02:02:14,940 --> 02:02:15,940
patch cable the numbers match
2895
02:02:18,840 --> 02:02:19,840
and well that's just a number into the
2896
02:02:21,360 --> 02:02:22,360
pins the colors of the different wires
2897
02:02:24,300 --> 02:02:25,300
inside match and that's you could tell
2898
02:02:26,580 --> 02:02:27,580
you would hold the cable together if you
2899
02:02:29,040 --> 02:02:30,040
didn't know if you wanted to see if it
2900
02:02:30,659 --> 02:02:31,659
was the right kind of cable hold it up
2901
02:02:32,340 --> 02:02:33,340
look at it and check that all the wire
2902
02:02:34,320 --> 02:02:35,320
colors match
2903
02:02:37,199 --> 02:02:38,199
now the worrying standards for the RJ45
2904
02:02:40,280 --> 02:02:41,280
is the um 568 amb they specify how to
2905
02:02:44,940 --> 02:02:45,940
wire the actual connector over an
2906
02:02:46,500 --> 02:02:47,500
Ethernet Network technically you could
2907
02:02:48,780 --> 02:02:49,780
choose any order of colors you like if
2908
02:02:51,719 --> 02:02:52,719
you were making your own cables
2909
02:02:53,820 --> 02:02:54,820
and as long as it matched the other side
2910
02:02:56,280 --> 02:02:57,280
then it would all work because the
2911
02:02:58,260 --> 02:02:59,260
cables inside the the eight little wires
2912
02:03:00,780 --> 02:03:01,780
are all exactly the same
2913
02:03:02,940 --> 02:03:03,940
but um you wouldn't obviously be
2914
02:03:04,500 --> 02:03:05,500
following the standards so maybe you
2915
02:03:06,540 --> 02:03:07,540
could do it for your home network if you
2916
02:03:07,920 --> 02:03:08,920
wanted to make your own cables but
2917
02:03:09,420 --> 02:03:10,420
certainly not recommended for commercial
2918
02:03:11,699 --> 02:03:12,699
Networks
2919
02:03:13,679 --> 02:03:14,679
so only one of the following standards
2920
02:03:15,480 --> 02:03:16,480
used for terminating ends of the UTP you
2921
02:03:18,480 --> 02:03:19,480
could choose either
2922
02:03:21,420 --> 02:03:22,420
and but I think I mentioned earlier the
2923
02:03:23,280 --> 02:03:24,280
recommendations for the horizontal
2924
02:03:24,900 --> 02:03:25,900
cables
2925
02:03:26,280 --> 02:03:27,280
so the example of a straight through
2926
02:03:27,659 --> 02:03:28,659
cable is computer or a server connecting
2927
02:03:31,139 --> 02:03:32,139
into a switch port
2928
02:03:33,780 --> 02:03:34,780
I've already mentioned that you wouldn't
2929
02:03:35,099 --> 02:03:36,099
use both standards on them on your cable
2930
02:03:41,880 --> 02:03:42,880
straight through cables are used when
2931
02:03:43,080 --> 02:03:44,080
connecting to an MDR device or an ndi
2932
02:03:45,960 --> 02:03:46,960
device to an mdix device
2933
02:03:49,980 --> 02:03:50,980
and again we've seen this this is just
2934
02:03:51,900 --> 02:03:52,900
zoomed in and giving you a better and
2935
02:03:54,119 --> 02:03:55,119
detailed image of the cable type here
2936
02:03:57,239 --> 02:03:58,239
if it's straight through UTB cable is
2937
02:03:58,920 --> 02:03:59,920
terminated on both sides using the type
2938
02:04:00,840 --> 02:04:01,840
a wiring
2939
02:04:02,280 --> 02:04:03,280
then the a color scheme and should be
2940
02:04:07,020 --> 02:04:08,020
so I'll say that again then the color
2941
02:04:08,639 --> 02:04:09,639
scheme and the pin out the order of the
2942
02:04:10,080 --> 02:04:11,080
connections will be shown in the diagram
2943
02:04:12,000 --> 02:04:13,000
so this is the a standard and you do it
2944
02:04:15,300 --> 02:04:16,300
a few times
2945
02:04:17,940 --> 02:04:18,940
um for a few days and then you probably
2946
02:04:19,560 --> 02:04:20,560
have it in your memory of what all data
2947
02:04:21,840 --> 02:04:22,840
put the wires in again if it was you
2948
02:04:24,599 --> 02:04:25,599
making the cables which um
2949
02:04:27,300 --> 02:04:28,300
wouldn't only really happen if you were
2950
02:04:29,940 --> 02:04:30,940
um
2951
02:04:30,599 --> 02:04:31,599
a cabling engineer for a very large
2952
02:04:32,520 --> 02:04:33,520
Network
2953
02:04:33,840 --> 02:04:34,840
and there's the pin outs and the colors
2954
02:04:36,719 --> 02:04:37,719
in more detail you can see the tip
2955
02:04:38,520 --> 02:04:39,520
transmit and the um receive indications
2956
02:04:42,659 --> 02:04:43,659
on either end there
2957
02:04:45,420 --> 02:04:46,420
so when a computer uses pins one and two
2958
02:04:48,119 --> 02:04:49,119
I have a pair of wise to transmit the
2959
02:04:51,060 --> 02:04:52,060
switch will receive those data on the
2960
02:04:52,800 --> 02:04:53,800
same pins
2961
02:04:54,480 --> 02:04:55,480
when I sit when a switch transmits the
2962
02:04:57,000 --> 02:04:58,000
data using pins three and six on a
2963
02:04:58,920 --> 02:04:59,920
different pair of wires the computer
2964
02:05:00,659 --> 02:05:01,659
will receive those so you can see here
2965
02:05:03,540 --> 02:05:04,540
TX is going to an RX and vice versa
2966
02:05:12,000 --> 02:05:13,000
um in the internet Network such as a 10
2967
02:05:14,219 --> 02:05:15,219
base t or 100 Base TX pins four and five
2968
02:05:17,040 --> 02:05:18,040
of the blue pad and pin seven and eight
2969
02:05:19,260 --> 02:05:20,260
of the brown pair are not used
2970
02:05:21,719 --> 02:05:22,719
so technically you could have a cable
2971
02:05:23,340 --> 02:05:24,340
that um doesn't
2972
02:05:25,199 --> 02:05:26,199
um have connections on those pins there
2973
02:05:28,199 --> 02:05:29,199
now you're more likely to be using a
2974
02:05:30,840 --> 02:05:31,840
faster and connection type if possible
2975
02:05:33,119 --> 02:05:34,119
so on the thousand base T ethernet cable
2976
02:05:35,940 --> 02:05:36,940
such as cat5v all four pairs of wires
2977
02:05:39,480 --> 02:05:40,480
will be used and that's how they get the
2978
02:05:41,099 --> 02:05:42,099
faster speed but using the same cable
2979
02:05:44,040 --> 02:05:45,040
types
2980
02:05:45,840 --> 02:05:46,840
now the crossover cable you can see here
2981
02:05:48,060 --> 02:05:49,060
is used to connect like to like so if
2982
02:05:51,179 --> 02:05:52,179
you have two switches then you could
2983
02:05:53,159 --> 02:05:54,159
connect them using a crossover cable two
2984
02:05:55,560 --> 02:05:56,560
router ethernet ports you could use a
2985
02:05:57,599 --> 02:05:58,599
crossover cable or if you had two PCS at
2986
02:06:00,360 --> 02:06:01,360
home and you didn't want to pay for a
2987
02:06:02,580 --> 02:06:03,580
switch you could also use a crossover
2988
02:06:04,020 --> 02:06:05,020
cable
2989
02:06:06,599 --> 02:06:07,599
used to connect the following MDI device
2990
02:06:08,880 --> 02:06:09,880
to an MDI device
2991
02:06:11,460 --> 02:06:12,460
you could also connect to um
2992
02:06:14,280 --> 02:06:15,280
switches together as we have here in the
2993
02:06:16,260 --> 02:06:17,260
diagram the MDI X device
2994
02:06:20,099 --> 02:06:21,099
okay wiring for UTP crossover cable
2995
02:06:22,739 --> 02:06:23,739
easiest way to remember is one goes to
2996
02:06:24,599 --> 02:06:25,599
three and two goes to six everything
2997
02:06:26,580 --> 02:06:27,580
else stays the same you can see that
2998
02:06:29,099 --> 02:06:30,099
rule applies for both sides so left to
2999
02:06:31,619 --> 02:06:32,619
right and right to left
3000
02:06:34,920 --> 02:06:35,920
a crossover UTP cable has an eight pin
3001
02:06:37,560 --> 02:06:38,560
modular connectors each end is
3002
02:06:39,780 --> 02:06:40,780
terminated in the below manner
3003
02:06:46,320 --> 02:06:47,320
okay so these devices will be
3004
02:06:47,940 --> 02:06:48,940
transmitted on the same pins one and two
3005
02:06:50,099 --> 02:06:51,099
these devices will also be receiving on
3006
02:06:52,139 --> 02:06:53,139
the same pins three and six might be
3007
02:06:54,840 --> 02:06:55,840
worth remembering that case that pops up
3008
02:06:56,699 --> 02:06:57,699
in the exam which ones are receiving and
3009
02:06:58,860 --> 02:06:59,860
which ones are transmitting
3010
02:07:01,139 --> 02:07:02,139
foreign
3011
02:07:05,119 --> 02:07:06,119
on one side is connected to pin three
3012
02:07:07,679 --> 02:07:08,679
that's what I said and two to six
3013
02:07:10,860 --> 02:07:11,860
terminating the crossover
3014
02:07:13,199 --> 02:07:14,199
you would terminate by using the um 568
3015
02:07:16,260 --> 02:07:17,260
a wiring on one side and the B wiring on
3016
02:07:19,320 --> 02:07:20,320
the other so using two different
3017
02:07:20,940 --> 02:07:21,940
standards for either end
3018
02:07:26,820 --> 02:07:27,820
um if we're on an end of the um cabling
3019
02:07:28,860 --> 02:07:29,860
uses the a standard the other has to use
3020
02:07:31,500 --> 02:07:32,500
the B that's if you're making the
3021
02:07:33,239 --> 02:07:34,239
crossover cable
3022
02:07:35,159 --> 02:07:36,159
Auto mdix
3023
02:07:37,980 --> 02:07:38,980
it's Auto sensing so do you remember
3024
02:07:40,020 --> 02:07:41,020
earlier we had this picture of a hub and
3025
02:07:43,080 --> 02:07:44,080
you had to press this um the little
3026
02:07:44,760 --> 02:07:45,760
switch on there while modern devices can
3027
02:07:48,179 --> 02:07:49,179
actually Auto sense what type of cables
3028
02:07:50,580 --> 02:07:51,580
attached and then change the designation
3029
02:07:53,520 --> 02:07:54,520
for how it uses which wires on the eight
3030
02:07:56,940 --> 02:07:57,940
pins on the inside
3031
02:08:00,599 --> 02:08:01,599
and most modern ethernet devices for
3032
02:08:03,119 --> 02:08:04,119
example switches use the auto MDI XV
3033
02:08:05,940 --> 02:08:06,940
channel so it's pretty handy
3034
02:08:08,040 --> 02:08:09,040
this is why sometimes you can plug the
3035
02:08:10,080 --> 02:08:11,080
wrong cable into a switch and it all
3036
02:08:12,780 --> 02:08:13,780
still works because it's got this
3037
02:08:14,340 --> 02:08:15,340
automatic feature
3038
02:08:16,199 --> 02:08:17,199
rollover cable is something you will
3039
02:08:17,880 --> 02:08:18,880
have with you normally at all times as a
3040
02:08:19,619 --> 02:08:20,619
network engineer in your briefcase
3041
02:08:22,139 --> 02:08:23,139
and normally used to connect your PC or
3042
02:08:25,800 --> 02:08:26,800
laptop to the console port on a router
3043
02:08:29,880 --> 02:08:30,880
or switch and it lets you
3044
02:08:31,800 --> 02:08:32,800
configure the device when you first buy
3045
02:08:33,780 --> 02:08:34,780
it and it's blank or do emergency
3046
02:08:36,239 --> 02:08:37,239
recovery for example if you've forgotten
3047
02:08:38,639 --> 02:08:39,639
a password to configure the router or
3048
02:08:40,800 --> 02:08:41,800
switch
3049
02:08:43,500 --> 02:08:44,500
so it has a 8p AC connector rs232 based
3050
02:08:47,580 --> 02:08:48,580
connector such as a DB9
3051
02:08:49,679 --> 02:08:50,679
this has actually changed now so you can
3052
02:08:51,780 --> 02:08:52,780
see the DB9 connector your laptops don't
3053
02:08:54,540 --> 02:08:55,540
actually come with DB9 connectors
3054
02:08:56,219 --> 02:08:57,219
anymore it's pretty old-fashioned so
3055
02:08:58,199 --> 02:08:59,199
what you'll do is you'll have a db92 USB
3056
02:09:00,719 --> 02:09:01,719
connector
3057
02:09:02,940 --> 02:09:03,940
um and you'll use one of your free
3058
02:09:06,179 --> 02:09:07,179
um common connections using device
3059
02:09:08,159 --> 02:09:09,159
manager to see which port to connect on
3060
02:09:14,219 --> 02:09:15,219
so I mentioned Cisco console cables and
3061
02:09:16,800 --> 02:09:17,800
recovering your Cisco router
3062
02:09:18,840 --> 02:09:19,840
in order to you can make your own
3063
02:09:21,420 --> 02:09:22,420
rollover cable roll over flat console
3064
02:09:24,239 --> 02:09:25,239
same thing cable
3065
02:09:26,040 --> 02:09:27,040
and the wires are basically reversed so
3066
02:09:28,560 --> 02:09:29,560
every yr goes to the opposite number one
3067
02:09:31,560 --> 02:09:32,560
goes to a two goes to seven three goes
3068
02:09:33,719 --> 02:09:34,719
to six and um carry on with that number
3069
02:09:36,960 --> 02:09:37,960
in so basically the whole thing's
3070
02:09:38,639 --> 02:09:39,639
Twisted somewhere in the middle
3071
02:09:42,119 --> 02:09:43,119
all right so we've covered modular
3072
02:09:43,920 --> 02:09:44,920
connectors the A and B wiring schemes
3073
02:09:46,760 --> 02:09:47,760
MDI and mdix straight through
3074
02:09:51,540 --> 02:09:52,540
and crossover cable
3075
02:09:55,619 --> 02:09:56,619
Auto mdix and brown leather cables so
3076
02:09:58,679 --> 02:09:59,679
that's all we need to look at for now
3077
02:10:00,480 --> 02:10:01,480
thanks for watching
3078
02:10:09,310 --> 02:10:10,310
[Music]
3079
02:10:26,280 --> 02:10:27,280
welcome to module 2 lesson 1B some more
3080
02:10:29,940 --> 02:10:30,940
cables connectors and transceivers this
3081
02:10:32,159 --> 02:10:33,159
is all new stuff that's landed into the
3082
02:10:34,260 --> 02:10:35,260
network plus syllabus
3083
02:10:36,119 --> 02:10:37,119
uh some of it's a little bit strange in
3084
02:10:38,219 --> 02:10:39,219
as much as it's almost redundant and I'm
3085
02:10:41,159 --> 02:10:42,159
guessing they want you to know this
3086
02:10:42,540 --> 02:10:43,540
stuff in case you come across it in an
3087
02:10:45,239 --> 02:10:46,239
environment for whatever reason
3088
02:10:47,400 --> 02:10:48,400
all right so Network Hardware media and
3089
02:10:50,159 --> 02:10:51,159
bound in network media a few things
3090
02:10:52,260 --> 02:10:53,260
we'll be looking at
3091
02:10:54,060 --> 02:10:55,060
copper connectors uh the stuff we
3092
02:10:56,880 --> 02:10:57,880
haven't already looked at earlier by the
3093
02:10:58,980 --> 02:10:59,980
way uh transceivers
3094
02:11:01,800 --> 02:11:02,800
some termination points copper cable
3095
02:11:04,320 --> 02:11:05,320
standards
3096
02:11:05,580 --> 02:11:06,580
and network storage connection types
3097
02:11:09,360 --> 02:11:10,360
so this is a used to be called uh d sub
3098
02:11:12,239 --> 02:11:13,239
actually but it seems to have been
3099
02:11:13,679 --> 02:11:14,679
hijacked into DB connectors but you can
3100
02:11:16,619 --> 02:11:17,619
see the um the shape of the connector
3101
02:11:18,840 --> 02:11:19,840
here is like the letter D really leave
3102
02:11:21,300 --> 02:11:22,300
it on its side
3103
02:11:23,580 --> 02:11:24,580
I like that so the theory is you can't
3104
02:11:27,540 --> 02:11:28,540
uh plug it in the wrong way I say in
3105
02:11:30,599 --> 02:11:31,599
theory because when I've run computer
3106
02:11:31,980 --> 02:11:32,980
courses it might just be a Cisco thing
3107
02:11:34,440 --> 02:11:35,440
because this looks a little bit thicker
3108
02:11:37,380 --> 02:11:38,380
but the uh the Cisco um
3109
02:11:40,619 --> 02:11:41,619
housing here I was so thin that the
3110
02:11:43,139 --> 02:11:44,139
students would come and somehow managed
3111
02:11:45,060 --> 02:11:46,060
to plug in the d-connector
3112
02:11:47,820 --> 02:11:48,820
for the serial cables upside down now
3113
02:11:51,480 --> 02:11:52,480
this did a couple of things it um a
3114
02:11:54,060 --> 02:11:55,060
things don't work when they're upside
3115
02:11:55,560 --> 02:11:56,560
down obviously with these tiny little
3116
02:11:57,659 --> 02:11:58,659
pins they're much smaller than the ones
3117
02:12:00,239 --> 02:12:01,239
you see here they actually got forced in
3118
02:12:03,659 --> 02:12:04,659
the wrong way and all got bent like that
3119
02:12:05,520 --> 02:12:06,520
so that actually cost me a lot of money
3120
02:12:07,020 --> 02:12:08,020
it was quite a distressing when I
3121
02:12:09,300 --> 02:12:10,300
started up my business
3122
02:12:11,099 --> 02:12:12,099
so this is the theory behind the shape
3123
02:12:13,739 --> 02:12:14,739
anyway I actually I don't know why I put
3124
02:12:16,320 --> 02:12:17,320
into male and connectors here I want to
3125
02:12:19,980 --> 02:12:20,980
do have one female but I put into male
3126
02:12:22,020 --> 02:12:23,020
used to see these on the back of an old
3127
02:12:24,659 --> 02:12:25,659
style PCS and um their laptops as well
3128
02:12:28,860 --> 02:12:29,860
you don't really see them anymore
3129
02:12:29,880 --> 02:12:30,880
because USBS have replaced all of it so
3130
02:12:32,820 --> 02:12:33,820
you'd have to be looking at a fairly old
3131
02:12:34,920 --> 02:12:35,920
machine
3132
02:12:36,420 --> 02:12:37,420
they were created a long long time ago
3133
02:12:38,699 --> 02:12:39,699
before I was born when my dad was a
3134
02:12:42,119 --> 02:12:43,119
young man as he used to say 1952
3135
02:12:44,900 --> 02:12:45,900
exclusively by Canon and it looks like
3136
02:12:47,340 --> 02:12:48,340
they've probably released a license so
3137
02:12:49,079 --> 02:12:50,079
that people could use them they were
3138
02:12:51,239 --> 02:12:52,239
used in toker ring networks I do
3139
02:12:53,159 --> 02:12:54,159
remember those support I actually
3140
02:12:55,079 --> 02:12:56,079
supported those for a while at Cisco
3141
02:12:57,179 --> 02:12:58,179
although there was hardly any left
3142
02:12:58,980 --> 02:12:59,980
it was pretty scary when somebody called
3143
02:13:00,900 --> 02:13:01,900
in with a token ring issue external
3144
02:13:03,840 --> 02:13:04,840
floppy drives if you remember those and
3145
02:13:06,179 --> 02:13:07,179
you'd buy an old real old probably
3146
02:13:07,679 --> 02:13:08,679
wasn't even a PC then it was a an Amiga
3147
02:13:10,560 --> 02:13:11,560
or Commodore 64 or something and you
3148
02:13:12,960 --> 02:13:13,960
could invest extra money to put these
3149
02:13:15,179 --> 02:13:16,179
floppy drives in and if you wanted to
3150
02:13:17,280 --> 02:13:18,280
load a game you probably have to
3151
02:13:18,599 --> 02:13:19,599
individually insert uh I think it was
3152
02:13:21,480 --> 02:13:22,480
around 10 floppy drives to upload each
3153
02:13:24,000 --> 02:13:25,000
part of the program and I think I did
3154
02:13:26,099 --> 02:13:27,099
have to do that for early versions of
3155
02:13:27,719 --> 02:13:28,719
Microsoft Word or the equivalent I used
3156
02:13:30,900 --> 02:13:31,900
in Mouse connectors also
3157
02:13:32,940 --> 02:13:33,940
as I said eventually replaced by USB
3158
02:13:35,579 --> 02:13:36,579
thank goodness
3159
02:13:37,380 --> 02:13:38,380
the D shape so I've covered this already
3160
02:13:40,320 --> 02:13:41,320
the theory is in fact I'm sure it works
3161
02:13:43,260 --> 02:13:44,260
for most people I'll just give you a
3162
02:13:44,579 --> 02:13:45,579
heads up there when I run Cisco it
3163
02:13:46,980 --> 02:13:47,980
didn't work that way
3164
02:13:48,960 --> 02:13:49,960
um I wanted the students to plug their
3165
02:13:50,760 --> 02:13:51,760
own cables in to have their confidence
3166
02:13:53,040 --> 02:13:54,040
but it kind of backfired a bit
3167
02:13:55,199 --> 02:13:56,199
I designed to work with the eia tia232
3168
02:13:58,860 --> 02:13:59,860
serial interface standard I guess you
3169
02:14:01,199 --> 02:14:02,199
should make it out of that for the exam
3170
02:14:03,900 --> 02:14:04,900
sort of silly question would be asked
3171
02:14:05,820 --> 02:14:06,820
the number DB whatever
3172
02:14:08,639 --> 02:14:09,639
so uh what would DB9 or db25 this is
3173
02:14:12,360 --> 02:14:13,360
supposed to refer to the amount of pins
3174
02:14:14,460 --> 02:14:15,460
that are in the male and female part so
3175
02:14:18,719 --> 02:14:19,719
it could be pretty hard to mix them up
3176
02:14:20,219 --> 02:14:21,219
actually looking at them you more like
3177
02:14:22,500 --> 02:14:23,500
to see the db25 on uh like a printer
3178
02:14:25,920 --> 02:14:26,920
cable or something like that again if
3179
02:14:28,079 --> 02:14:29,079
you see it at all
3180
02:14:29,579 --> 02:14:30,579
now the F connector F-Type has been
3181
02:14:32,460 --> 02:14:33,460
added to the syllabus not to be confused
3182
02:14:34,739 --> 02:14:35,739
with fiber cables such as stlc SC which
3183
02:14:39,300 --> 02:14:40,300
are covered elsewhere in the in the
3184
02:14:41,699 --> 02:14:42,699
course here
3185
02:14:43,800 --> 02:14:44,800
so it's a coaxial RF connector type
3186
02:14:47,420 --> 02:14:48,420
used more commonly for cable satellite
3187
02:14:51,239 --> 02:14:52,239
TV if you've got the back of a box you
3188
02:14:54,360 --> 02:14:55,360
can see here there's a thread on the
3189
02:14:56,699 --> 02:14:57,699
inside of the cable here and you'd have
3190
02:14:58,199 --> 02:14:59,199
to turn it round and it'd lock in with
3191
02:15:02,099 --> 02:15:03,099
the TR so you'd have to hopefully with
3192
02:15:04,920 --> 02:15:05,920
enough finger pressure be able to secure
3193
02:15:07,079 --> 02:15:08,079
it into place and then unscrew it those
3194
02:15:10,199 --> 02:15:11,199
are when you need to
3195
02:15:11,579 --> 02:15:12,579
TV antennas for those user on on using
3196
02:15:14,940 --> 02:15:15,940
them your Broadband or Ethernet or
3197
02:15:17,579 --> 02:15:18,579
whatever
3198
02:15:18,900 --> 02:15:19,900
bandwidth could go up to several
3199
02:15:20,400 --> 02:15:21,400
gigahertz
3200
02:15:22,560 --> 02:15:23,560
uh punch down blocks this is a pretty
3201
02:15:25,380 --> 02:15:26,380
tricky skill really and one that takes a
3202
02:15:27,360 --> 02:15:28,360
bit of time but you can see here the
3203
02:15:30,360 --> 02:15:31,360
cable has just been placed in between
3204
02:15:33,000 --> 02:15:34,000
the runners and then the punch down tool
3205
02:15:35,880 --> 02:15:36,880
has kind of got this shape as you can
3206
02:15:38,639 --> 02:15:39,639
see here
3207
02:15:40,079 --> 02:15:41,079
and this would force the cable in and
3208
02:15:42,900 --> 02:15:43,900
the theory is it would strip back some
3209
02:15:45,599 --> 02:15:46,599
of this uh coating for the wire and
3210
02:15:48,239 --> 02:15:49,239
create a contact inside the punch down
3211
02:15:50,639 --> 02:15:51,639
block takes a bit of skill and it's
3212
02:15:53,460 --> 02:15:54,460
quite frustrating if you don't do it
3213
02:15:54,840 --> 02:15:55,840
right or if someone hasn't used the
3214
02:15:56,340 --> 02:15:57,340
correct tool it leads to this nightmare
3215
02:15:58,560 --> 02:15:59,560
of intermittent connectivity that you'll
3216
02:16:01,500 --> 02:16:02,500
have to go and troubleshoot
3217
02:16:03,840 --> 02:16:04,840
you'll typically see this in inside a
3218
02:16:06,719 --> 02:16:07,719
telephone switch
3219
02:16:08,460 --> 02:16:09,460
um
3220
02:16:09,420 --> 02:16:10,420
as switch mechanisms a couple wires
3221
02:16:12,659 --> 02:16:13,659
punched down as I said
3222
02:16:14,520 --> 02:16:15,520
the numbers are for these models are
3223
02:16:17,940 --> 02:16:18,940
given uh 66 Block it's a model number so
3224
02:16:21,420 --> 02:16:22,420
it doesn't mean the 66 connectors
3225
02:16:23,880 --> 02:16:24,880
that particular one has 55 rows it was
3226
02:16:27,360 --> 02:16:28,360
subject to crosstalk which is known uh
3227
02:16:29,639 --> 02:16:30,639
quite known quite well in the industry
3228
02:16:32,280 --> 02:16:33,280
had a reputation for that not suitable
3229
02:16:34,979 --> 02:16:35,979
for high speed connections of 100 Meg or
3230
02:16:39,359 --> 02:16:40,359
um or hayab
3231
02:16:41,160 --> 02:16:42,160
now the 100 block replaced the 66 block
3232
02:16:44,460 --> 02:16:45,460
so just remember the numbers here the 66
3233
02:16:48,179 --> 02:16:49,179
block hopefully they won't try and catch
3234
02:16:50,340 --> 02:16:51,340
you out with the um question saying it's
3235
02:16:52,620 --> 02:16:53,620
got 66 Connections in it's a model
3236
02:16:54,540 --> 02:16:55,540
number just to confuse you
3237
02:16:56,880 --> 02:16:57,880
often used the 100 is to terminate cable
3238
02:17:00,000 --> 02:17:01,000
runs
3239
02:17:01,859 --> 02:17:02,859
the fiber distribution plan and panel
3240
02:17:04,200 --> 02:17:05,200
how to get images of this but I've I've
3241
02:17:06,120 --> 02:17:07,120
got one that you can actually uh buy
3242
02:17:08,160 --> 02:17:09,160
from the manufacturer this one obviously
3243
02:17:10,439 --> 02:17:11,439
hasn't been set up at all it's a bare
3244
02:17:12,660 --> 02:17:13,660
bone system that you would run all of
3245
02:17:15,120 --> 02:17:16,120
the cables through here and then
3246
02:17:18,179 --> 02:17:19,179
terminate
3247
02:17:19,320 --> 02:17:20,320
so this is also known as the fiber
3248
02:17:21,479 --> 02:17:22,479
Distribution Hub if you're searching for
3249
02:17:23,700 --> 02:17:24,700
one to buy I think they give you
3250
02:17:25,679 --> 02:17:26,679
different terms depending on which part
3251
02:17:27,240 --> 02:17:28,240
of the country you're in or which
3252
02:17:28,979 --> 02:17:29,979
country and at the bottom here I've got
3253
02:17:31,139 --> 02:17:32,139
a URL for a particular company that
3254
02:17:34,260 --> 02:17:35,260
sells them
3255
02:17:35,399 --> 02:17:36,399
obviously speak to the sales advisor and
3256
02:17:37,320 --> 02:17:38,320
find out what you need
3257
02:17:39,120 --> 02:17:40,120
saves you um making expensive mistakes
3258
02:17:41,700 --> 02:17:42,700
this is the patch panel used to
3259
02:17:43,920 --> 02:17:44,920
terminate fiber optic cables
3260
02:17:46,620 --> 02:17:47,620
access to the cables individual strands
3261
02:17:49,859 --> 02:17:50,859
the so the strands inside the cable for
3262
02:17:53,099 --> 02:17:54,099
cross connection
3263
02:17:54,780 --> 02:17:55,780
now I do apologize for this however
3264
02:17:58,620 --> 02:17:59,620
um
3265
02:17:59,460 --> 02:18:00,460
it's in the syllabus now for some crazy
3266
02:18:01,559 --> 02:18:02,559
reason previously we had um other RG
3267
02:18:05,219 --> 02:18:06,219
standards I think it was
3268
02:18:07,280 --> 02:18:08,280
rg9 or and RG58 I'll have to check you
3269
02:18:11,880 --> 02:18:12,880
you can see it in earlier presentations
3270
02:18:13,920 --> 02:18:14,920
anyway however now they've asked for RG6
3271
02:18:17,040 --> 02:18:18,040
and
3272
02:18:18,139 --> 02:18:19,139
rg59 so I've highlighted what you need
3273
02:18:20,939 --> 02:18:21,939
to do I suggest you make some notes
3274
02:18:24,120 --> 02:18:25,120
as to um impedance which is all the same
3275
02:18:27,000 --> 02:18:28,000
actually so it shouldn't be too easy
3276
02:18:30,300 --> 02:18:31,300
um
3277
02:18:30,979 --> 02:18:31,979
shielding here and then just make a note
3278
02:18:34,260 --> 02:18:35,260
of what they've what they've said here
3279
02:18:36,240 --> 02:18:37,240
so
3280
02:18:38,040 --> 02:18:39,040
um
3281
02:18:38,660 --> 02:18:39,660
RG6
3282
02:18:40,260 --> 02:18:41,260
uh Slash U what is used for the uq
3283
02:18:45,300 --> 02:18:46,300
again this is just such a pain and it's
3284
02:18:47,519 --> 02:18:48,519
silly because you'd if you're having
3285
02:18:49,500 --> 02:18:50,500
anything to do with this you just check
3286
02:18:51,719 --> 02:18:52,719
the documentation before you went on
3287
02:18:54,000 --> 02:18:55,000
site it's very unlikely most Engineers
3288
02:18:56,340 --> 02:18:57,340
if you asked most Network engineers and
3289
02:18:59,040 --> 02:19:00,040
what can you tell me about rg59 Slash U
3290
02:19:01,859 --> 02:19:02,859
there's probably not a lot they could
3291
02:19:03,660 --> 02:19:04,660
say however I don't make the rules it's
3292
02:19:06,179 --> 02:19:07,179
in the syllabus so just take notes and
3293
02:19:08,939 --> 02:19:09,939
just chop that up to something you're
3294
02:19:11,099 --> 02:19:12,099
gonna have to learn
3295
02:19:12,240 --> 02:19:13,240
uh transceivers I've got some images
3296
02:19:14,280 --> 02:19:15,280
here these are for um the SPF SPF plus
3297
02:19:17,639 --> 02:19:18,639
and gbic which are connectors for Cisco
3298
02:19:21,719 --> 02:19:22,719
equipment these
3299
02:19:24,179 --> 02:19:25,179
um
3300
02:19:25,439 --> 02:19:26,439
these would stand proud from the switch
3301
02:19:27,540 --> 02:19:28,540
chassis and then this would be inserted
3302
02:19:29,939 --> 02:19:30,939
in and make contact to the back of the
3303
02:19:31,920 --> 02:19:32,920
chassis so here's the front of the
3304
02:19:33,840 --> 02:19:34,840
chassis here here and you wouldn't
3305
02:19:36,240 --> 02:19:37,240
actually see the back and there's this
3306
02:19:38,099 --> 02:19:39,099
has got a nice thin slot that you would
3307
02:19:41,160 --> 02:19:42,160
insert to
3308
02:19:43,380 --> 02:19:44,380
yeah
3309
02:19:44,939 --> 02:19:45,939
do the 3D version so transceiver is
3310
02:19:48,300 --> 02:19:49,300
short for transmitter receiver as we
3311
02:19:50,100 --> 02:19:51,100
mentioned earlier it converts the
3312
02:19:51,840 --> 02:19:52,840
electrical signals from one type to
3313
02:19:53,760 --> 02:19:54,760
another type so serial to Optical
3314
02:19:55,979 --> 02:19:56,979
signals and vice versa
3315
02:19:59,160 --> 02:20:00,160
The Cisco gigabit internet interface
3316
02:20:02,280 --> 02:20:03,280
converter we call them gbx it's hot
3317
02:20:04,800 --> 02:20:05,800
swappable so you pull it out push it
3318
02:20:06,899 --> 02:20:07,899
back in again hot swappable here
3319
02:20:09,960 --> 02:20:10,960
is very handy and I think we'll come to
3320
02:20:12,359 --> 02:20:13,359
this later actually to find my cursor it
3321
02:20:15,780 --> 02:20:16,780
means you don't have to power down your
3322
02:20:17,460 --> 02:20:18,460
unit which is just absolute gold if
3323
02:20:20,340 --> 02:20:21,340
you're working in a production Network
3324
02:20:21,600 --> 02:20:22,600
because it's just horrible especially if
3325
02:20:24,000 --> 02:20:25,000
you've got paying customers that are
3326
02:20:26,640 --> 02:20:27,640
paying for
3327
02:20:27,859 --> 02:20:28,859
99.999 recurring up time and then you
3328
02:20:31,200 --> 02:20:32,200
tell them you've got a power down the
3329
02:20:32,939 --> 02:20:33,939
device they're connected to and just to
3330
02:20:35,220 --> 02:20:36,220
swap out something so very handy plugs
3331
02:20:37,680 --> 02:20:38,680
into the gigabit Ethernet port or slot
3332
02:20:41,720 --> 02:20:42,720
SPF stands for small form factor
3333
02:20:45,359 --> 02:20:46,359
pluggable I guess a gigabit interface
3334
02:20:47,460 --> 02:20:48,460
converter that too is hot swappable bear
3335
02:20:50,460 --> 02:20:51,460
in mind what you've got to do is check
3336
02:20:52,560 --> 02:20:53,560
for
3337
02:20:55,680 --> 02:20:56,680
bugs so if say for example you've got a
3338
02:20:59,220 --> 02:21:00,220
Cisco device and you've read the
3339
02:21:01,680 --> 02:21:02,680
documentation and it says hot swappable
3340
02:21:03,560 --> 02:21:04,560
you ask them to do if you've got a
3341
02:21:06,359 --> 02:21:07,359
contract a bug
3342
02:21:10,340 --> 02:21:11,340
sweep for the
3343
02:21:12,899 --> 02:21:13,899
say for example this with the model so
3344
02:21:16,800 --> 02:21:17,800
say WC
3345
02:21:19,640 --> 02:21:20,640
36 whatever the model is you say I've
3346
02:21:23,280 --> 02:21:24,280
got this switch this model uh it says
3347
02:21:25,680 --> 02:21:26,680
it's hot swappable and just do a bug
3348
02:21:28,500 --> 02:21:29,500
sweep this is I only tell you this
3349
02:21:30,840 --> 02:21:31,840
because and this is the advantage of
3350
02:21:32,520 --> 02:21:33,520
having someone like myself not that I'm
3351
02:21:35,040 --> 02:21:36,040
boasting but I worked at Cisco
3352
02:21:37,380 --> 02:21:38,380
and we had a customer who asked one of
3353
02:21:41,100 --> 02:21:42,100
our Engineers if something was hot
3354
02:21:43,080 --> 02:21:44,080
swappable the documentation said it was
3355
02:21:45,660 --> 02:21:46,660
however
3356
02:21:47,640 --> 02:21:48,640
um not that it was his fault there was a
3357
02:21:49,260 --> 02:21:50,260
bug which he didn't know about and the
3358
02:21:52,560 --> 02:21:53,560
customer hot swapped it brought down a
3359
02:21:55,020 --> 02:21:56,020
core switch it caused a massive amount
3360
02:21:57,540 --> 02:21:58,540
of problems there was I think some legal
3361
02:21:59,520 --> 02:22:00,520
claims or whatever it's just headaches
3362
02:22:01,800 --> 02:22:02,800
you don't need so if you've got the
3363
02:22:04,380 --> 02:22:05,380
contract
3364
02:22:05,520 --> 02:22:06,520
and just because it says hot swappable
3365
02:22:07,439 --> 02:22:08,439
don't necessarily take that on face
3366
02:22:10,020 --> 02:22:11,020
value and if you if you can log a ticket
3367
02:22:12,359 --> 02:22:13,359
or do a search
3368
02:22:15,120 --> 02:22:16,120
SPF plus is in the hearts version the
3369
02:22:17,580 --> 02:22:18,580
hint is in the plus that supports higher
3370
02:22:19,859 --> 02:22:20,859
data rates and this time up to 16
3371
02:22:22,680 --> 02:22:23,680
gigabits per second
3372
02:22:25,319 --> 02:22:26,319
and then finally I don't have a picture
3373
02:22:26,939 --> 02:22:27,939
here a quad small form factable a factor
3374
02:22:30,420 --> 02:22:31,420
plugable and you've got different speeds
3375
02:22:33,600 --> 02:22:34,600
just check the documentation on that I
3376
02:22:36,359 --> 02:22:37,359
just wanted to um flag it up I think
3377
02:22:39,180 --> 02:22:40,180
it's actually in the syllabus also
3378
02:22:41,479 --> 02:22:42,479
uh so we've just got the ghibit module
3379
02:22:45,180 --> 02:22:46,180
here and you can see the uh the chassis
3380
02:22:47,819 --> 02:22:48,819
would actually be here so you wouldn't
3381
02:22:49,260 --> 02:22:50,260
see all this typically and then you'd
3382
02:22:51,720 --> 02:22:52,720
have obviously the slot here and I
3383
02:22:53,700 --> 02:22:54,700
mentioned that only the the end bit
3384
02:22:56,220 --> 02:22:57,220
would be proud and you've got two fiber
3385
02:22:59,220 --> 02:23:00,220
cables in here I'm not sure what this
3386
02:23:01,140 --> 02:23:02,140
model of the model is that it's actually
3387
02:23:03,300 --> 02:23:04,300
plugging into we're just having a sneaky
3388
02:23:05,700 --> 02:23:06,700
look here at the um circuit board is SPF
3389
02:23:10,020 --> 02:23:11,020
plus and
3390
02:23:12,540 --> 02:23:13,540
um yeah so just so you can see it
3391
02:23:14,819 --> 02:23:15,819
working in an actual device and however
3392
02:23:17,700 --> 02:23:18,700
you would set this up I'm not sure if
3393
02:23:19,200 --> 02:23:20,200
this is um these have been linked
3394
02:23:21,240 --> 02:23:22,240
together all the ones operating as a
3395
02:23:23,280 --> 02:23:24,280
backup to the other so you can see what
3396
02:23:25,380 --> 02:23:26,380
it would look like on a live environment
3397
02:23:28,439 --> 02:23:29,439
and network storage fiber channel fiber
3398
02:23:30,960 --> 02:23:31,960
channel ever ethernet it basically
3399
02:23:33,000 --> 02:23:34,000
encapsulates fiber channel frames over
3400
02:23:35,160 --> 02:23:36,160
ethernet it's a protocol in its own
3401
02:23:37,439 --> 02:23:38,439
right and it was developed just
3402
02:23:39,300 --> 02:23:40,300
specifically for this environment and
3403
02:23:41,580 --> 02:23:42,580
you can see the um fiber channel over
3404
02:23:43,740 --> 02:23:44,740
ethernet is working in this part of the
3405
02:23:46,920 --> 02:23:47,920
connection here
3406
02:23:49,260 --> 02:23:50,260
and then it looks like we've got ether
3407
02:23:51,000 --> 02:23:52,000
channel here which um I don't think
3408
02:23:54,000 --> 02:23:55,000
ether channel is specifically covered
3409
02:23:55,740 --> 02:23:56,740
but we do
3410
02:23:56,880 --> 02:23:57,880
um there's a part of the syllabus that
3411
02:23:59,520 --> 02:24:00,520
covers um increase in Europe time I
3412
02:24:02,399 --> 02:24:03,399
can't remember what it's called now
3413
02:24:04,020 --> 02:24:05,020
let's say there's redundancy we do talk
3414
02:24:06,060 --> 02:24:07,060
about later
3415
02:24:07,380 --> 02:24:08,380
so uh it's a non-routable network
3416
02:24:09,420 --> 02:24:10,420
protocol so it won't go
3417
02:24:12,060 --> 02:24:13,060
whatever your connection is it wouldn't
3418
02:24:14,580 --> 02:24:15,580
be
3419
02:24:15,720 --> 02:24:16,720
carried out here to um
3420
02:24:18,300 --> 02:24:19,300
to the internet
3421
02:24:20,939 --> 02:24:21,939
it wouldn't work it'd be converted
3422
02:24:23,340 --> 02:24:24,340
something would be converted to bgp or
3423
02:24:25,740 --> 02:24:26,740
whatever you're using out here
3424
02:24:28,680 --> 02:24:29,680
differs from Isco Z which runs over
3425
02:24:30,540 --> 02:24:31,540
tcpip
3426
02:24:32,819 --> 02:24:33,819
okay this is non-routable so that very
3427
02:24:34,740 --> 02:24:35,740
much whether it would be working over
3428
02:24:35,880 --> 02:24:36,880
tcpip and then just to tick the Box
3429
02:24:39,240 --> 02:24:40,240
Infinity band it's added in the syllabus
3430
02:24:42,600 --> 02:24:43,600
um there's a diagram here I got from
3431
02:24:44,760 --> 02:24:45,760
melanox whoever they are just you could
3432
02:24:48,660 --> 02:24:49,660
um see a topology of it working used in
3433
02:24:52,319 --> 02:24:53,319
high performance Computing just think of
3434
02:24:54,300 --> 02:24:55,300
exam questions basically why is it used
3435
02:24:56,819 --> 02:24:57,819
it's high performance low latency so if
3436
02:25:00,240 --> 02:25:01,240
it if it meets your requirements you'd
3437
02:25:02,040 --> 02:25:03,040
consider using it
3438
02:25:03,840 --> 02:25:04,840
uh direct or switched internet
3439
02:25:05,520 --> 02:25:06,520
connection between servers or storage so
3440
02:25:08,520 --> 02:25:09,520
it can be server to serve our server to
3441
02:25:10,380 --> 02:25:11,380
storage
3442
02:25:12,060 --> 02:25:13,060
all right so we covered a lot of ground
3443
02:25:14,040 --> 02:25:15,040
but we're just topping up on what we uh
3444
02:25:16,740 --> 02:25:17,740
already learned earlier you learn about
3445
02:25:18,660 --> 02:25:19,660
some copper connector types transceivers
3446
02:25:21,840 --> 02:25:22,840
so it'll convert one type of another one
3447
02:25:25,680 --> 02:25:26,680
type of connection to another we talked
3448
02:25:27,840 --> 02:25:28,840
about the the DB oops the DB M9 uh I
3449
02:25:33,720 --> 02:25:34,720
think the other one was 25 the D
3450
02:25:35,399 --> 02:25:36,399
connector and basically the shape is
3451
02:25:37,620 --> 02:25:38,620
there
3452
02:25:38,580 --> 02:25:39,580
hopefully so nobody plugs things in the
3453
02:25:41,040 --> 02:25:42,040
wrong way that's any reason
3454
02:25:42,960 --> 02:25:43,960
uh termination points copper cable
3455
02:25:45,840 --> 02:25:46,840
standards which is the F standard I
3456
02:25:48,840 --> 02:25:49,840
think we talked about which isn't fiber
3457
02:25:53,399 --> 02:25:54,399
it could be fiber fibre depending on
3458
02:25:56,460 --> 02:25:57,460
where you are
3459
02:25:57,660 --> 02:25:58,660
and then the network storage connection
3460
02:25:59,340 --> 02:26:00,340
type
3461
02:26:00,720 --> 02:26:01,720
all right so that's all for now I'll
3462
02:26:02,700 --> 02:26:03,700
look forward to seeing you on the next
3463
02:26:03,840 --> 02:26:04,840
presentation
3464
02:26:09,290 --> 02:26:10,290
[Music]
3465
02:26:17,640 --> 02:26:18,640
foreign
3466
02:26:29,280 --> 02:26:30,280
Network hardware and media unbounded
3467
02:26:32,580 --> 02:26:33,580
Network media
3468
02:26:34,080 --> 02:26:35,080
as we just discussed bounded media is
3469
02:26:36,660 --> 02:26:37,660
that media error cabling that is bounded
3470
02:26:38,939 --> 02:26:39,939
in the limits of a cable something you
3471
02:26:42,300 --> 02:26:43,300
can hold unbounded media as the image
3472
02:26:45,479 --> 02:26:46,479
here describes and the image right here
3473
02:26:47,520 --> 02:26:48,520
describes is uh Wireless in nature
3474
02:26:50,760 --> 02:26:51,760
meaning that there isn't any sort of
3475
02:26:52,740 --> 02:26:53,740
chord that you have to rely on and
3476
02:26:55,200 --> 02:26:56,200
therefore it allows for certain
3477
02:26:57,359 --> 02:26:58,359
advantages and also certain
3478
02:26:58,920 --> 02:26:59,920
disadvantages so we're going to look at
3479
02:27:00,840 --> 02:27:01,840
the hardware and unbounded media types
3480
02:27:03,319 --> 02:27:04,319
involved in these sort of connections
3481
02:27:06,240 --> 02:27:07,240
so are the objectives for this module
3482
02:27:09,479 --> 02:27:10,479
are to Define unbounded as opposed to
3483
02:27:12,420 --> 02:27:13,420
bounded Network media we're also going
3484
02:27:15,060 --> 02:27:16,060
to define the difference in radio
3485
02:27:16,620 --> 02:27:17,620
networking and broadcast radio
3486
02:27:19,979 --> 02:27:20,979
look at something called spread Spectrum
3487
02:27:23,100 --> 02:27:24,100
which was created in order to help
3488
02:27:27,240 --> 02:27:28,240
Wireless Technologies work more
3489
02:27:29,640 --> 02:27:30,640
efficiently and effectively we're also
3490
02:27:31,740 --> 02:27:32,740
going to look at IR or infrared or
3491
02:27:33,660 --> 02:27:34,660
infrared connections Bluetooth
3492
02:27:35,580 --> 02:27:36,580
connections and microwave connections
3493
02:27:38,460 --> 02:27:39,460
all of these different types of
3494
02:27:39,960 --> 02:27:40,960
unbounded media and devices
3495
02:27:42,540 --> 02:27:43,540
and then we're going to look at
3496
02:27:43,560 --> 02:27:44,560
something that most of you are probably
3497
02:27:44,939 --> 02:27:45,939
more familiar with a wireless access
3498
02:27:46,859 --> 02:27:47,859
point also a WAP
3499
02:27:50,460 --> 02:27:51,460
then we're going to describe the
3500
02:27:51,479 --> 02:27:52,479
characteristics of an SSID which many of
3501
02:27:54,840 --> 02:27:55,840
you uh might know as the name of a
3502
02:27:57,300 --> 02:27:58,300
network also called the service set
3503
02:27:59,040 --> 02:28:00,040
identifier
3504
02:28:00,600 --> 02:28:01,600
and finally we're going to look at the
3505
02:28:03,060 --> 02:28:04,060
basic uh
3506
02:28:04,620 --> 02:28:05,620
ways of properly installing an access
3507
02:28:06,899 --> 02:28:07,899
point and by properly installing an
3508
02:28:09,240 --> 02:28:10,240
access point of course we're referring
3509
02:28:11,700 --> 02:28:12,700
to the network plus methodology of
3510
02:28:15,000 --> 02:28:16,000
installing an access point
3511
02:28:16,680 --> 02:28:17,680
all right
3512
02:28:19,140 --> 02:28:20,140
so unbounded Network media is any
3513
02:28:22,200 --> 02:28:23,200
network media that's not bound by a
3514
02:28:24,960 --> 02:28:25,960
physical connection such as copper or
3515
02:28:27,180 --> 02:28:28,180
wire a fiber that we've just seen
3516
02:28:30,420 --> 02:28:31,420
the unbounded simply means it's wireless
3517
02:28:33,300 --> 02:28:34,300
or it's using a sort of Wireless
3518
02:28:35,880 --> 02:28:36,880
technology Now using unbounded media has
3519
02:28:39,840 --> 02:28:40,840
some specific advantages such as it's
3520
02:28:42,720 --> 02:28:43,720
easier to install and manage over its
3521
02:28:45,120 --> 02:28:46,120
bounded counterparts because you don't
3522
02:28:46,680 --> 02:28:47,680
have as much stuff to deal with in the
3523
02:28:49,560 --> 02:28:50,560
same regard however unbounded Network
3524
02:28:51,540 --> 02:28:52,540
media has the potential to be less
3525
02:28:53,700 --> 02:28:54,700
secure than bounded and actually a lot
3526
02:28:57,600 --> 02:28:58,600
of folks will say that there is no way
3527
02:28:59,520 --> 02:29:00,520
to have a secure Wireless
3528
02:29:01,800 --> 02:29:02,800
or unbounded network because
3529
02:29:05,819 --> 02:29:06,819
traffic across the network can be
3530
02:29:07,920 --> 02:29:08,920
intercepted a lot easier when it's
3531
02:29:10,319 --> 02:29:11,319
wireless and anyone can just sort of tap
3532
02:29:12,000 --> 02:29:13,000
in in radio networking data is
3533
02:29:15,300 --> 02:29:16,300
transmitted as RF or radio frequency so
3534
02:29:19,979 --> 02:29:20,979
one of the first forms of communications
3535
02:29:22,520 --> 02:29:23,520
this these signals of RF waves were
3536
02:29:26,939 --> 02:29:27,939
transmitted in the 10 kilohertz to
3537
02:29:33,140 --> 02:29:34,140
uh one gigahertz range
3538
02:29:37,040 --> 02:29:38,040
and in the U.S the FCC or the Federal
3539
02:29:40,080 --> 02:29:41,080
Communications Commission regulates
3540
02:29:42,420 --> 02:29:43,420
these radio Transmissions this kind of
3541
02:29:45,120 --> 02:29:46,120
networking is unfortunately very
3542
02:29:46,620 --> 02:29:47,620
susceptible to uh Emi
3543
02:29:50,220 --> 02:29:51,220
or electromagnetic interference which
3544
02:29:52,380 --> 02:29:53,380
we've seen previously especially from
3545
02:29:54,780 --> 02:29:55,780
stuff like power lines metallic
3546
02:29:57,359 --> 02:29:58,359
obstacles even atmospheric conditions
3547
02:30:00,060 --> 02:30:01,060
some people tell me that they lose
3548
02:30:01,859 --> 02:30:02,859
connectivity when a plane flies overhead
3549
02:30:05,160 --> 02:30:06,160
a radio networking can also be very long
3550
02:30:08,700 --> 02:30:09,700
range depending on the method of
3551
02:30:11,040 --> 02:30:12,040
transmission the amount of power behind
3552
02:30:13,319 --> 02:30:14,319
the signal the kind of antenna being
3553
02:30:15,720 --> 02:30:16,720
used the portion of the frequency
3554
02:30:18,240 --> 02:30:19,240
spectrum which is located in here that's
3555
02:30:21,780 --> 02:30:22,780
being used now with broadcast radio
3556
02:30:24,960 --> 02:30:25,960
which is also considered a broadcast
3557
02:30:27,060 --> 02:30:28,060
network the signal is sent out in all
3558
02:30:29,700 --> 02:30:30,700
directions and utilizes a single
3559
02:30:31,800 --> 02:30:32,800
frequency for transmission so there's
3560
02:30:34,140 --> 02:30:35,140
low power transmission for shorter
3561
02:30:36,540 --> 02:30:37,540
distances is more common and is easy to
3562
02:30:39,420 --> 02:30:40,420
install but there's also
3563
02:30:41,460 --> 02:30:42,460
high power Transmissions which are used
3564
02:30:44,280 --> 02:30:45,280
for further distances as you would
3565
02:30:45,780 --> 02:30:46,780
imagine and it's difficult typically a
3566
02:30:48,240 --> 02:30:49,240
little more difficult to install because
3567
02:30:49,680 --> 02:30:50,680
it requires really specially trained
3568
02:30:52,200 --> 02:30:53,200
technicians proper installation and
3569
02:30:54,060 --> 02:30:55,060
maintenance techniques and so on with
3570
02:30:56,580 --> 02:30:57,580
radio networking line of sight is not
3571
02:30:59,460 --> 02:31:00,460
necessary
3572
02:31:00,600 --> 02:31:01,600
which means that the
3573
02:31:02,460 --> 02:31:03,460
uh this the device sending the signal in
3574
02:31:05,160 --> 02:31:06,160
the device receiving the signal don't
3575
02:31:06,540 --> 02:31:07,540
need to literally be able to see one
3576
02:31:08,640 --> 02:31:09,640
another now because radio networking is
3577
02:31:11,580 --> 02:31:12,580
sent over the airwaves uh the signal can
3578
02:31:14,580 --> 02:31:15,580
be intercepted really easily and so in
3579
02:31:16,859 --> 02:31:17,859
order to utilize the technology for
3580
02:31:19,319 --> 02:31:20,319
day-to-day transmission of information
3581
02:31:21,080 --> 02:31:22,080
we need to make sure that it's kept
3582
02:31:23,340 --> 02:31:24,340
confidential and so a new form of radio
3583
02:31:26,040 --> 02:31:27,040
transmission was developed this is
3584
02:31:28,620 --> 02:31:29,620
called spread Spectrum
3585
02:31:31,500 --> 02:31:32,500
a spread Spectrum was introduced to
3586
02:31:33,899 --> 02:31:34,899
address some of the concerns that I've
3587
02:31:36,120 --> 02:31:37,120
just mentioned uh it takes the radio
3588
02:31:38,580 --> 02:31:39,580
signal to be transmitted and it sends it
3589
02:31:41,580 --> 02:31:42,580
over more than one frequency so this
3590
02:31:44,280 --> 02:31:45,280
makes it more difficult to intercept the
3591
02:31:46,439 --> 02:31:47,439
data in transit now there are two
3592
02:31:48,240 --> 02:31:49,240
different types of spread spectrums
3593
02:31:50,280 --> 02:31:51,280
first is DSS or direct sequence spread
3594
02:31:53,880 --> 02:31:54,880
Spectrum the direct sequence
3595
02:31:57,200 --> 02:31:58,200
spread Spectrum that's a mouthful
3596
02:31:59,960 --> 02:32:00,960
utilizes multiple channels to transmit
3597
02:32:03,479 --> 02:32:04,479
the message simultaneously
3598
02:32:06,300 --> 02:32:07,300
so it's going to use multiple channels
3599
02:32:09,960 --> 02:32:10,960
and it's going to send that message
3600
02:32:12,720 --> 02:32:13,720
all at the same time
3601
02:32:16,260 --> 02:32:17,260
with DSS there's also a method of error
3602
02:32:18,780 --> 02:32:19,780
checking and it's called edac
3603
02:32:21,720 --> 02:32:22,720
which I don't think you'll see on the
3604
02:32:22,979 --> 02:32:23,979
test which is error detection and
3605
02:32:24,899 --> 02:32:25,899
correction and this allows for a certain
3606
02:32:26,780 --> 02:32:27,780
degree of signal loss while still being
3607
02:32:29,819 --> 02:32:30,819
able to put the original signal back
3608
02:32:31,500 --> 02:32:32,500
together on the receiving end
3609
02:32:36,420 --> 02:32:37,420
on the other hand we also have something
3610
02:32:37,920 --> 02:32:38,920
called fhss or frequency hopping spread
3611
02:32:41,880 --> 02:32:42,880
Spectrum in this method uh it sends the
3612
02:32:45,060 --> 02:32:46,060
signal across one channel at a time
3613
02:32:50,100 --> 02:32:51,100
and hops to the channel uh each Channel
3614
02:32:53,220 --> 02:32:54,220
just just sort of hops to another one at
3615
02:32:55,380 --> 02:32:56,380
a predetermined interval
3616
02:32:59,220 --> 02:33:00,220
this method can hop from frequency to
3617
02:33:01,140 --> 02:33:02,140
frequency anywhere from 50 to a several
3618
02:33:04,319 --> 02:33:05,319
hundred uh different frequencies
3619
02:33:13,319 --> 02:33:14,319
per second
3620
02:33:14,760 --> 02:33:15,760
the sender and receiver as you can
3621
02:33:16,200 --> 02:33:17,200
imagine need to be synchronized with one
3622
02:33:17,760 --> 02:33:18,760
another and they also have to have the
3623
02:33:19,080 --> 02:33:20,080
same uh set of frequencies to hop to
3624
02:33:22,859 --> 02:33:23,859
which which is called a hop set
3625
02:33:26,660 --> 02:33:27,660
this method of radio communication by
3626
02:33:29,160 --> 02:33:30,160
the way is it's commonly used in the
3627
02:33:31,500 --> 02:33:32,500
military because it has a fairly
3628
02:33:35,939 --> 02:33:36,939
strong sense of security about it
3629
02:33:40,819 --> 02:33:41,819
infrared or infrared which you might
3630
02:33:44,040 --> 02:33:45,040
have heard of uh
3631
02:33:47,819 --> 02:33:48,819
Transmissions
3632
02:33:49,439 --> 02:33:50,439
are also unbounded forms of
3633
02:33:51,420 --> 02:33:52,420
communication and the and the data is
3634
02:33:53,880 --> 02:33:54,880
sent via pulses of infrared light
3635
02:33:57,420 --> 02:33:58,420
hence the name infrared this light is ah
3636
02:34:01,260 --> 02:34:02,260
between 300 gigahertz and 300 000
3637
02:34:04,920 --> 02:34:05,920
gigahertz range and in the in the
3638
02:34:07,620 --> 02:34:08,620
electromagnetic spectrum of ranges and
3639
02:34:10,020 --> 02:34:11,020
frequencies there are also a few types
3640
02:34:11,880 --> 02:34:12,880
of ir that can be used
3641
02:34:14,100 --> 02:34:15,100
um all of which need an absolutely
3642
02:34:15,800 --> 02:34:16,800
unobstructed view between devices this
3643
02:34:18,660 --> 02:34:19,660
means that they are what we call line of
3644
02:34:21,300 --> 02:34:22,300
sight
3645
02:34:23,700 --> 02:34:24,700
or loss
3646
02:34:32,819 --> 02:34:33,819
because of this it nearly guarantees
3647
02:34:34,979 --> 02:34:35,979
that there's a secure connection between
3648
02:34:36,479 --> 02:34:37,479
the devices because they have to be so
3649
02:34:38,280 --> 02:34:39,280
close to one another
3650
02:34:39,720 --> 02:34:40,720
another example of infrared being used
3651
02:34:41,700 --> 02:34:42,700
by the way is your remote control which
3652
02:34:45,060 --> 02:34:46,060
is the reason that we probably found
3653
02:34:46,200 --> 02:34:47,200
them on a lot of laptops now there are
3654
02:34:48,359 --> 02:34:49,359
different types of infrared connections
3655
02:34:50,580 --> 02:34:51,580
uh they're serial infrared which means
3656
02:34:53,399 --> 02:34:54,399
that the data is sent in a Serial
3657
02:34:55,500 --> 02:34:56,500
fashion uh in this case you're looking
3658
02:34:58,140 --> 02:34:59,140
at probably around 115
3659
02:35:01,740 --> 02:35:02,740
kilobits per second then we also have
3660
02:35:04,500 --> 02:35:05,500
fast infrared which goes up to four
3661
02:35:07,380 --> 02:35:08,380
megabits per second and finally very
3662
02:35:10,740 --> 02:35:11,740
fast infrared which gives you up to
3663
02:35:13,380 --> 02:35:14,380
about 16 megabits per second so you can
3664
02:35:16,140 --> 02:35:17,140
see that there is a uh the technology
3665
02:35:18,600 --> 02:35:19,600
has changed quite a bit that being said
3666
02:35:21,240 --> 02:35:22,240
we don't see this a lot in sort of um
3667
02:35:23,760 --> 02:35:24,760
consumer markets just because it is uh
3668
02:35:27,420 --> 02:35:28,420
because of the line of sight necessity
3669
02:35:29,700 --> 02:35:30,700
of it
3670
02:35:30,600 --> 02:35:31,600
now there's also Bluetooth Transmissions
3671
02:35:33,000 --> 02:35:34,000
which is another form of short range
3672
02:35:35,700 --> 02:35:36,700
wireless communication it's increasingly
3673
02:35:38,100 --> 02:35:39,100
popular you've probably seen it with
3674
02:35:40,080 --> 02:35:41,080
these sort of headsets and it uses a 2.4
3675
02:35:43,200 --> 02:35:44,200
gigahertz frequency which by the way is
3676
02:35:46,260 --> 02:35:47,260
the same we're going to see with Wi-Fi
3677
02:35:48,420 --> 02:35:49,420
and so that this can actually cause uh
3678
02:35:51,300 --> 02:35:52,300
some interference with your at-home
3679
02:35:53,760 --> 02:35:54,760
Wi-Fi network now today Bluetooth is
3680
02:35:56,160 --> 02:35:57,160
used to connect devices like headsets
3681
02:35:58,020 --> 02:35:59,020
cell phones uh laptops mice gaming
3682
02:36:01,500 --> 02:36:02,500
consoles
3683
02:36:03,060 --> 02:36:04,060
um so on and so forth
3684
02:36:05,040 --> 02:36:06,040
the accepted maximum range of Bluetooth
3685
02:36:08,600 --> 02:36:09,600
communication is about 30 feet uh which
3686
02:36:12,660 --> 02:36:13,660
is equivalent to around 10 meters
3687
02:36:16,140 --> 02:36:17,140
but the newest implementation Bluetooth
3688
02:36:18,060 --> 02:36:19,060
2.0 is said to reach up to 30 meters or
3689
02:36:21,600 --> 02:36:22,600
a hundred feet uh but it's not
3690
02:36:24,060 --> 02:36:25,060
guaranteed to run that distance and
3691
02:36:26,640 --> 02:36:27,640
um in application it might not actually
3692
02:36:28,439 --> 02:36:29,439
get there now when you're connecting
3693
02:36:30,420 --> 02:36:31,420
devices by bluetooth we call it pairing
3694
02:36:33,420 --> 02:36:34,420
devices uh and if you've never done this
3695
02:36:36,120 --> 02:36:37,120
before generally there's a pin code
3696
02:36:37,859 --> 02:36:38,859
that's used
3697
02:36:39,840 --> 02:36:40,840
to pin these a pair these devices
3698
02:36:42,600 --> 02:36:43,600
together to make sure that they are
3699
02:36:43,920 --> 02:36:44,920
secure and you're not connecting to a
3700
02:36:45,240 --> 02:36:46,240
different device the next type of uh
3701
02:36:47,700 --> 02:36:48,700
Wireless transmission I want to talk
3702
02:36:49,620 --> 02:36:50,620
about is microwave transmission is the
3703
02:36:52,020 --> 02:36:53,020
same
3704
02:36:52,740 --> 02:36:53,740
term for that thing in your house the
3705
02:36:55,439 --> 02:36:56,439
microwave operates in one one gigahertz
3706
02:36:57,720 --> 02:36:58,720
to 300 gigahertz frequency range and for
3707
02:37:02,100 --> 02:37:03,100
the microwave transmission to be
3708
02:37:04,140 --> 02:37:05,140
received successfully there has to be an
3709
02:37:06,300 --> 02:37:07,300
unobstructed view or point-to-point line
3710
02:37:09,540 --> 02:37:10,540
of
3711
02:37:10,880 --> 02:37:11,880
communication so just imagine that the
3712
02:37:15,180 --> 02:37:16,180
satellite uh for your television for
3713
02:37:17,520 --> 02:37:18,520
instance if our satellite dish at home
3714
02:37:19,620 --> 02:37:20,620
doesn't have a clear line to the
3715
02:37:21,180 --> 02:37:22,180
satellite in the sky we see that it's
3716
02:37:23,399 --> 02:37:24,399
signal to grade or drop off altogether
3717
02:37:26,040 --> 02:37:27,040
so obstructions such as buildings uh
3718
02:37:28,920 --> 02:37:29,920
trees even atmospheric conditions like
3719
02:37:31,620 --> 02:37:32,620
rain Etc can all play a major factor in
3720
02:37:34,500 --> 02:37:35,500
microwave Transmissions one of the
3721
02:37:36,660 --> 02:37:37,660
greatest benefits of microwave
3722
02:37:38,580 --> 02:37:39,580
Transmissions is it has a really long
3723
02:37:40,800 --> 02:37:41,800
range of communication as you can
3724
02:37:42,600 --> 02:37:43,600
imagine
3725
02:37:43,680 --> 02:37:44,680
uh uh your satellite at home can reach
3726
02:37:47,700 --> 02:37:48,700
all the way up to the sky and hit that
3727
02:37:49,439 --> 02:37:50,439
uh satellite in the sky or rather your
3728
02:37:51,840 --> 02:37:52,840
receiver at home or your dish at home
3729
02:37:53,340 --> 02:37:54,340
can reach that satellite in the sky and
3730
02:37:55,620 --> 02:37:56,620
so there's a real strong benefit to the
3731
02:37:57,540 --> 02:37:58,540
satellite microwave Transmissions
3732
02:38:00,180 --> 02:38:01,180
now the one you're probably most
3733
02:38:02,100 --> 02:38:03,100
familiar with here is a wireless access
3734
02:38:03,840 --> 02:38:04,840
point which is a radio uh a type of
3735
02:38:07,200 --> 02:38:08,200
radio frequency device it allows
3736
02:38:09,840 --> 02:38:10,840
wireless
3737
02:38:10,819 --> 02:38:11,819
devices to connect to a network it has a
3738
02:38:15,540 --> 02:38:16,540
network interface that allows it to
3739
02:38:17,160 --> 02:38:18,160
connect to a wired Network as well so
3740
02:38:19,859 --> 02:38:20,859
generally speaking this would go off to
3741
02:38:22,859 --> 02:38:23,859
say a switch or a router now how do we
3742
02:38:25,439 --> 02:38:26,439
know which wireless access point we want
3743
02:38:27,240 --> 02:38:28,240
to connect to this is something this is
3744
02:38:29,520 --> 02:38:30,520
where we get into something called an
3745
02:38:30,840 --> 02:38:31,840
SSID and there are also other settings
3746
02:38:33,960 --> 02:38:34,960
that we need to take care of when we're
3747
02:38:36,000 --> 02:38:37,000
setting one of these up so first let's
3748
02:38:37,740 --> 02:38:38,740
talk about the SSID or service set
3749
02:38:40,260 --> 02:38:41,260
identifier which is a up to a 32-bit
3750
02:38:43,640 --> 02:38:44,640
alphanumeric string and it identifies
3751
02:38:47,340 --> 02:38:48,340
the name of your wireless access point
3752
02:38:50,640 --> 02:38:51,640
so in some ways we might call this the
3753
02:38:53,399 --> 02:38:54,399
name of your network right out of the
3754
02:38:55,560 --> 02:38:56,560
box
3755
02:38:56,399 --> 02:38:57,399
when you just set it up the access point
3756
02:38:59,340 --> 02:39:00,340
is going to do what we call broadcast
3757
02:39:01,040 --> 02:39:02,040
your SSID this means that it's
3758
02:39:04,140 --> 02:39:05,140
transmitting the name of the network uh
3759
02:39:06,660 --> 02:39:07,660
into clear text so that anyone who's
3760
02:39:08,880 --> 02:39:09,880
within range can see it if you live in a
3761
02:39:11,340 --> 02:39:12,340
building or if you're in an office space
3762
02:39:13,020 --> 02:39:14,020
you've probably seen this so This
3763
02:39:15,000 --> 02:39:16,000
creates a vulnerability on the network
3764
02:39:16,740 --> 02:39:17,740
especially if you want to limit the
3765
02:39:18,300 --> 02:39:19,300
number of users that are trying to
3766
02:39:20,520 --> 02:39:21,520
access your network so with your
3767
02:39:22,500 --> 02:39:23,500
wireless access point there are a few
3768
02:39:24,660 --> 02:39:25,660
steps to make to ensure that we're going
3769
02:39:27,660 --> 02:39:28,660
to install this correctly uh safely and
3770
02:39:30,000 --> 02:39:31,000
efficiently so the first thing we want
3771
02:39:32,100 --> 02:39:33,100
to do is to choose the proper device for
3772
02:39:34,979 --> 02:39:35,979
your needs obviously there are different
3773
02:39:37,260 --> 02:39:38,260
types of access points if you were
3774
02:39:39,120 --> 02:39:40,120
around for a plus we talked about what
3775
02:39:41,100 --> 02:39:42,100
are called Soho routers or Soho access
3776
02:39:43,680 --> 02:39:44,680
points which also have routers in them
3777
02:39:45,660 --> 02:39:46,660
but an access point simply is the device
3778
02:39:47,640 --> 02:39:48,640
that's connecting you wirelessly to your
3779
02:39:50,340 --> 02:39:51,340
network now if you have a corporate
3780
02:39:51,780 --> 02:39:52,780
environment or a home office Network
3781
02:39:53,280 --> 02:39:54,280
you're going to need different things so
3782
02:39:55,740 --> 02:39:56,740
the next thing one once you've decided
3783
02:39:57,300 --> 02:39:58,300
which device you want we then have to
3784
02:39:59,040 --> 02:40:00,040
talk about where we want to place it and
3785
02:40:01,859 --> 02:40:02,859
specifically we need to ensure that our
3786
02:40:03,780 --> 02:40:04,780
users can access the network from all
3787
02:40:06,240 --> 02:40:07,240
the places they need to which is just as
3788
02:40:08,340 --> 02:40:09,340
important as considering which users we
3789
02:40:10,140 --> 02:40:11,140
don't want to be able to connect so we
3790
02:40:11,760 --> 02:40:12,760
want to be able to place it in a place
3791
02:40:13,020 --> 02:40:14,020
that is of course Central but also is
3792
02:40:16,620 --> 02:40:17,620
limiting or Limited in the amount of
3793
02:40:19,020 --> 02:40:20,020
people who are going to connect to it if
3794
02:40:20,340 --> 02:40:21,340
you put it near a window for instance
3795
02:40:21,420 --> 02:40:22,420
our next door neighbor might be able to
3796
02:40:22,920 --> 02:40:23,920
connect now almost immediately after
3797
02:40:24,720 --> 02:40:25,720
bringing the whapper the wireless access
3798
02:40:27,780 --> 02:40:28,780
point out of the box we want to change
3799
02:40:29,939 --> 02:40:30,939
the administrative default password
3800
02:40:32,520 --> 02:40:33,520
so and disable any guest accounts this
3801
02:40:34,979 --> 02:40:35,979
means that all these settings that we're
3802
02:40:36,479 --> 02:40:37,479
talking about uh you need a password to
3803
02:40:39,420 --> 02:40:40,420
be able to get in and change them so we
3804
02:40:40,740 --> 02:40:41,740
want to change that or disable the guest
3805
02:40:43,560 --> 02:40:44,560
account change that and we also want to
3806
02:40:46,020 --> 02:40:47,020
make sure there are no other backdoor
3807
02:40:47,580 --> 02:40:48,580
accounts
3808
02:40:48,840 --> 02:40:49,840
um you can generally check in your
3809
02:40:50,220 --> 02:40:51,220
administrative sort of um manual to see
3810
02:40:53,040 --> 02:40:54,040
if there's anything like that so that
3811
02:40:54,840 --> 02:40:55,840
way we don't have any unauthorized
3812
02:40:56,220 --> 02:40:57,220
access to the account
3813
02:40:58,200 --> 02:40:59,200
next thing we want to do is configure
3814
02:41:00,359 --> 02:41:01,359
these wireless access point settings
3815
02:41:02,880 --> 02:41:03,880
including the SSID what encryption we're
3816
02:41:05,399 --> 02:41:06,399
using power and so on
3817
02:41:08,760 --> 02:41:09,760
we'll talk about encryption and in
3818
02:41:11,280 --> 02:41:12,280
further detail in later uh lessons so
3819
02:41:15,000 --> 02:41:16,000
don't worry about that so much right now
3820
02:41:19,380 --> 02:41:20,380
figurations have been set we also want
3821
02:41:21,660 --> 02:41:22,660
to disable as we've mentioned the SSID
3822
02:41:24,060 --> 02:41:25,060
this doesn't mean that users aren't
3823
02:41:25,439 --> 02:41:26,439
going to be able to connect to the
3824
02:41:26,880 --> 02:41:27,880
network by the way it just means that if
3825
02:41:29,160 --> 02:41:30,160
you're looking for available wireless
3826
02:41:31,620 --> 02:41:32,620
networks it's not going to be uh
3827
02:41:34,500 --> 02:41:35,500
broadcast out there so in other words
3828
02:41:36,300 --> 02:41:37,300
you need to know the name in order to
3829
02:41:38,040 --> 02:41:39,040
find it it's sort of like a door that's
3830
02:41:39,780 --> 02:41:40,780
hidden in the wall if you know where the
3831
02:41:41,760 --> 02:41:42,760
door is you can find it if not it Just
3832
02:41:43,740 --> 02:41:44,740
Blends into the wall
3833
02:41:45,240 --> 02:41:46,240
finally after we've set everything up
3834
02:41:46,920 --> 02:41:47,920
the last thing we want to do is test for
3835
02:41:48,359 --> 02:41:49,359
functionality make sure that all the
3836
02:41:50,160 --> 02:41:51,160
users can connect make sure that they
3837
02:41:52,680 --> 02:41:53,680
can get in from the locations they need
3838
02:41:54,180 --> 02:41:55,180
to and also make sure that people who
3839
02:41:56,220 --> 02:41:57,220
can't who shouldn't be able to connect
3840
02:41:57,420 --> 02:41:58,420
can't
3841
02:41:58,979 --> 02:41:59,979
all right so now we've talked about a
3842
02:42:01,020 --> 02:42:02,020
couple different things first we talked
3843
02:42:02,520 --> 02:42:03,520
about unbounded Network media which
3844
02:42:05,640 --> 02:42:06,640
again is sort of Wireless
3845
02:42:08,580 --> 02:42:09,580
in scope it means there's no chord we
3846
02:42:11,580 --> 02:42:12,580
looked at Radio networking and broadcast
3847
02:42:14,100 --> 02:42:15,100
radio we also looked at the sped spread
3848
02:42:18,120 --> 02:42:19,120
spectrum and if you remember that's we
3849
02:42:20,640 --> 02:42:21,640
have two different types one which is
3850
02:42:22,380 --> 02:42:23,380
going to broadcast on several different
3851
02:42:26,220 --> 02:42:27,220
channels on the Spectrum at once and one
3852
02:42:29,100 --> 02:42:30,100
which hops around at certain intervals
3853
02:42:32,220 --> 02:42:33,220
we also looked at infrared Bluetooth and
3854
02:42:35,100 --> 02:42:36,100
microwave connections these two much
3855
02:42:37,740 --> 02:42:38,740
more uh shorter distances microwave a
3856
02:42:41,100 --> 02:42:42,100
much longer distance this requires a
3857
02:42:43,680 --> 02:42:44,680
line of sight so does
3858
02:42:45,780 --> 02:42:46,780
IR Bluetooth does not but does have a
3859
02:42:48,840 --> 02:42:49,840
very limited degree of um distance that
3860
02:42:52,140 --> 02:42:53,140
it'll work we also looked at a wireless
3861
02:42:54,240 --> 02:42:55,240
access point or a WAP by the way
3862
02:42:58,920 --> 02:42:59,920
wireless access point is also going to
3863
02:43:00,899 --> 02:43:01,899
be built into what's called a Soho
3864
02:43:02,580 --> 02:43:03,580
router those are those Linksys or
3865
02:43:03,899 --> 02:43:04,899
Netgear routers that you buy at the
3866
02:43:05,220 --> 02:43:06,220
store and finally we described the
3867
02:43:07,020 --> 02:43:08,020
characteristics of an SSID specifically
3868
02:43:09,600 --> 02:43:10,600
the fact that we want to disable their
3869
02:43:11,520 --> 02:43:12,520
broadcasting
3870
02:43:16,859 --> 02:43:17,859
so we've talked about the bounded and
3871
02:43:19,020 --> 02:43:20,020
Unbound media let's talk about some of
3872
02:43:20,520 --> 02:43:21,520
the devices this media is going to
3873
02:43:21,960 --> 02:43:22,960
connect to
3874
02:43:25,560 --> 02:43:26,560
[Music]
3875
02:43:45,560 --> 02:43:46,560
Network hardware and media network
3876
02:43:49,020 --> 02:43:50,020
connectivity devices
3877
02:43:52,439 --> 02:43:53,439
so having discussed the way that devices
3878
02:43:55,319 --> 02:43:56,319
connect either using unbounded or
3879
02:43:58,020 --> 02:43:59,020
bounded media let's now talk about the
3880
02:44:00,600 --> 02:44:01,600
connectivity devices themselves
3881
02:44:03,420 --> 02:44:04,420
so the objectives of this module are
3882
02:44:05,700 --> 02:44:06,700
first to Define and describe a Nick
3883
02:44:08,100 --> 02:44:09,100
which also stands for a network
3884
02:44:10,640 --> 02:44:11,640
interface card
3885
02:44:13,859 --> 02:44:14,859
this is the main way in which devices
3886
02:44:16,319 --> 02:44:17,319
connect to a network
3887
02:44:24,420 --> 02:44:25,420
we're also going to talk about a
3888
02:44:26,580 --> 02:44:27,580
transceiver a chip that is on the Nick
3889
02:44:28,800 --> 02:44:29,800
and basically allows it to communicate
3890
02:44:31,920 --> 02:44:32,920
we're also going to identify the
3891
02:44:34,560 --> 02:44:35,560
characteristics that make a switch one
3892
02:44:37,200 --> 02:44:38,200
of the main Central devices in our start
3893
02:44:39,840 --> 02:44:40,840
apology that allows for communication on
3894
02:44:43,080 --> 02:44:44,080
a local area network and then we're
3895
02:44:45,420 --> 02:44:46,420
going to identify some of the qualities
3896
02:44:48,420 --> 02:44:49,420
and some of the characteristics that we
3897
02:44:50,939 --> 02:44:51,939
can put into a switch including trunking
3898
02:44:53,100 --> 02:44:54,100
Port mirroring and channel bonding all
3899
02:44:56,160 --> 02:44:57,160
of these do come up on the exam and so
3900
02:44:57,899 --> 02:44:58,899
they are pretty important to cover
3901
02:45:00,000 --> 02:45:01,000
then we're going to talk about a router
3902
02:45:01,859 --> 02:45:02,859
and a Gateway these two devices allow us
3903
02:45:04,560 --> 02:45:05,560
to communicate outside of our local
3904
02:45:06,420 --> 02:45:07,420
networks onto a wide area network or a
3905
02:45:09,000 --> 02:45:10,000
Wan
3906
02:45:10,080 --> 02:45:11,080
now as with anything we have noise that
3907
02:45:13,319 --> 02:45:14,319
interrupts the signal and so we're going
3908
02:45:15,180 --> 02:45:16,180
to talk about what that noise is and the
3909
02:45:17,819 --> 02:45:18,819
sources of that noise so we can better
3910
02:45:19,880 --> 02:45:20,880
uh alleviate and avoid it
3911
02:45:23,460 --> 02:45:24,460
finally we're going to talk about that
3912
02:45:25,319 --> 02:45:26,319
alleviation and avoidance by talking
3913
02:45:27,720 --> 02:45:28,720
about noise control and reduction
3914
02:45:29,939 --> 02:45:30,939
techniques sometimes getting into these
3915
02:45:33,479 --> 02:45:34,479
specifics of how this works now some of
3916
02:45:35,880 --> 02:45:36,880
this might be a little too complex for
3917
02:45:37,859 --> 02:45:38,859
the network plus exam but it's good to
3918
02:45:41,040 --> 02:45:42,040
go over anyway so you have a firm basis
3919
02:45:42,840 --> 02:45:43,840
in the theory behind it
3920
02:45:44,520 --> 02:45:45,520
so the Nick or the network interface
3921
02:45:48,300 --> 02:45:49,300
card is a physical connectivity device
3922
02:45:51,420 --> 02:45:52,420
that can be either wired or Wireless for
3923
02:45:56,340 --> 02:45:57,340
Wired networks the Nix gonna have an
3924
02:45:59,220 --> 02:46:00,220
ethernet port which is right here that
3925
02:46:02,399 --> 02:46:03,399
allows you to connect to an RJ45 cable
3926
02:46:05,460 --> 02:46:06,460
if you recall the RJ45 cable is the ones
3927
02:46:09,060 --> 02:46:10,060
used with most uh twisted pair
3928
02:46:12,080 --> 02:46:13,080
installations you can either connect it
3929
02:46:14,880 --> 02:46:15,880
directly to the motherboard or it can be
3930
02:46:19,200 --> 02:46:20,200
connected through another card or a
3931
02:46:21,000 --> 02:46:22,000
riser card or an expansion bus as this
3932
02:46:23,280 --> 02:46:24,280
one would be now there are typically
3933
02:46:25,500 --> 02:46:26,500
connectivity lights uh on the outside of
3934
02:46:28,920 --> 02:46:29,920
the Nic that allow administrators to get
3935
02:46:31,200 --> 02:46:32,200
a a quick status of the network
3936
02:46:33,300 --> 02:46:34,300
connection the connectivity lights can
3937
02:46:35,819 --> 02:46:36,819
mean different things depending on the
3938
02:46:37,740 --> 02:46:38,740
manufacture of the Nick however most
3939
02:46:39,840 --> 02:46:40,840
commonly there are going to be at least
3940
02:46:41,280 --> 02:46:42,280
two and possibly even three and each of
3941
02:46:44,040 --> 02:46:45,040
those lights are going to be different
3942
02:46:45,060 --> 02:46:46,060
colors you can see on this one we have
3943
02:46:46,859 --> 02:46:47,859
three different lights
3944
02:46:48,960 --> 02:46:49,960
there should be one light that is on to
3945
02:46:51,380 --> 02:46:52,380
dictate that there is a connection
3946
02:46:54,359 --> 02:46:55,359
that would be a solid green light most
3947
02:46:57,180 --> 02:46:58,180
of the time and it's going to stay lit
3948
02:46:59,280 --> 02:47:00,280
when connection and there's also going
3949
02:47:01,020 --> 02:47:02,020
to be another light that's sort of going
3950
02:47:02,580 --> 02:47:03,580
to flicker the flicker is letting you
3951
02:47:05,040 --> 02:47:06,040
know that there is activity or that
3952
02:47:06,720 --> 02:47:07,720
traffic is being sent across the neck
3953
02:47:08,939 --> 02:47:09,939
the faster the flicker uh typically this
3954
02:47:12,000 --> 02:47:13,000
means that the higher the network speed
3955
02:47:14,340 --> 02:47:15,340
or the more data that's going over
3956
02:47:16,220 --> 02:47:17,220
occasionally you might see one with
3957
02:47:18,359 --> 02:47:19,359
different colored lights the different
3958
02:47:20,280 --> 02:47:21,280
colors might dictate for instance the
3959
02:47:22,560 --> 02:47:23,560
speed of the connection for instance a
3960
02:47:24,780 --> 02:47:25,780
green for gigabit speeds which would be
3961
02:47:27,840 --> 02:47:28,840
a thousand megabits per second and Amber
3962
02:47:30,600 --> 02:47:31,600
for instance for uh 100 megabit speed
3963
02:47:33,720 --> 02:47:34,720
across the network okay and this is
3964
02:47:35,580 --> 02:47:36,580
going to really vary depending on the
3965
02:47:38,100 --> 02:47:39,100
Nick it's also important to know that
3966
02:47:40,140 --> 02:47:41,140
the MAC address which might be written
3967
02:47:42,960 --> 02:47:43,960
out here is actually hardwired or hard
3968
02:47:46,380 --> 02:47:47,380
uh coded into the neck so it's something
3969
02:47:49,620 --> 02:47:50,620
that comes with the Nick itself now a
3970
02:47:52,439 --> 02:47:53,439
transceiver is a Connect every device
3971
02:47:55,380 --> 02:47:56,380
that has the ability to send transmit or
3972
02:47:59,220 --> 02:48:00,220
receive traffic simultaneously the
3973
02:48:02,580 --> 02:48:03,580
ability that this has is special is due
3974
02:48:05,640 --> 02:48:06,640
to a specialized chip that's right here
3975
02:48:08,220 --> 02:48:09,220
and this assists the Nick in
3976
02:48:11,340 --> 02:48:12,340
transmitting traffic across the medium
3977
02:48:14,160 --> 02:48:15,160
almost every modern Nic has a
3978
02:48:16,979 --> 02:48:17,979
transceiver built directly on to the
3979
02:48:19,979 --> 02:48:20,979
device now a great example of a
3980
02:48:22,140 --> 02:48:23,140
transceiver at work is something called
3981
02:48:23,939 --> 02:48:24,939
the gbic or gigabit interface converter
3982
02:48:28,700 --> 02:48:29,700
this is something that allows the
3983
02:48:31,920 --> 02:48:32,920
conversion of electrical signals
3984
02:48:40,100 --> 02:48:41,100
into Optical signals
3985
02:48:46,439 --> 02:48:47,439
and then back again
3986
02:48:49,620 --> 02:48:50,620
the gbit can also be used to convert
3987
02:48:51,899 --> 02:48:52,899
different Optical Technologies from one
3988
02:48:53,939 --> 02:48:54,939
to the other and this the benefit of
3989
02:48:56,100 --> 02:48:57,100
this is it allows a network to be
3990
02:48:57,540 --> 02:48:58,540
upgraded without actually having to
3991
02:48:59,340 --> 02:49:00,340
upgrade all of the components so if
3992
02:49:01,500 --> 02:49:02,500
we're going to be using for instance
3993
02:49:03,540 --> 02:49:04,540
fiber optics and copper on the same
3994
02:49:06,420 --> 02:49:07,420
network this is something that we're
3995
02:49:07,920 --> 02:49:08,920
really going to want I wouldn't worry
3996
02:49:09,600 --> 02:49:10,600
too much about transceivers for the
3997
02:49:11,520 --> 02:49:12,520
network plus exam but I did want to
3998
02:49:13,020 --> 02:49:14,020
cover them because they are listed on
3999
02:49:15,000 --> 02:49:16,000
the um
4000
02:49:16,380 --> 02:49:17,380
uh on the outline and as I mentioned
4001
02:49:19,200 --> 02:49:20,200
they're really built onto a Nick so it's
4002
02:49:21,359 --> 02:49:22,359
sort of a subset of a Nick something
4003
02:49:23,280 --> 02:49:24,280
that is on the Nick that allows it to
4004
02:49:25,260 --> 02:49:26,260
transmit and receive that data and also
4005
02:49:27,899 --> 02:49:28,899
allows it to convert sometimes those
4006
02:49:30,180 --> 02:49:31,180
signals from one into the other so this
4007
02:49:32,160 --> 02:49:33,160
is how a computer is going to connect
4008
02:49:33,479 --> 02:49:34,479
let's talk about switches a switch is a
4009
02:49:36,540 --> 02:49:37,540
connectivity device that connects
4010
02:49:38,700 --> 02:49:39,700
multiple nodes together acting as the
4011
02:49:41,939 --> 02:49:42,939
common Connecting Point if you think
4012
02:49:43,920 --> 02:49:44,920
back to our start topology we have all
4013
02:49:46,500 --> 02:49:47,500
the nodes connected in this way now the
4014
02:49:49,439 --> 02:49:50,439
switch looks at something called the MAC
4015
02:49:52,500 --> 02:49:53,500
address or that physical address that's
4016
02:49:55,260 --> 02:49:56,260
burned onto the uh uh Nick it's a 48
4017
02:50:01,979 --> 02:50:02,979
bit
4018
02:50:03,800 --> 02:50:04,800
hexadecimal address and we will talk
4019
02:50:06,600 --> 02:50:07,600
more about it later
4020
02:50:08,700 --> 02:50:09,700
and what it does is it looks at the MAC
4021
02:50:11,040 --> 02:50:12,040
address of each packet of data to ensure
4022
02:50:13,859 --> 02:50:14,859
the data goes to the proper destination
4023
02:50:16,439 --> 02:50:17,439
or to the node for which it is meant now
4024
02:50:20,160 --> 02:50:21,160
because of this because the switch looks
4025
02:50:23,220 --> 02:50:24,220
at the MAC address of each packet it
4026
02:50:25,920 --> 02:50:26,920
ensures that traffic is only going to
4027
02:50:28,380 --> 02:50:29,380
the intended recipient a managed switch
4028
02:50:33,000 --> 02:50:34,000
just going to write that in here
4029
02:50:35,580 --> 02:50:36,580
is a switch that allows an administrator
4030
02:50:37,920 --> 02:50:38,920
access to its configuration and is able
4031
02:50:41,819 --> 02:50:42,819
to be monitored now the way that this
4032
02:50:44,100 --> 02:50:45,100
works is that there's generally
4033
02:50:45,780 --> 02:50:46,780
something called a console port on the
4034
02:50:49,020 --> 02:50:50,020
back of the device and you use something
4035
02:50:51,000 --> 02:50:52,000
called a console cable in order to
4036
02:50:54,300 --> 02:50:55,300
access this depending on the manufacture
4037
02:50:57,120 --> 02:50:58,120
of the switch this might be light blue
4038
02:50:59,520 --> 02:51:00,520
for instance in Cisco switches which is
4039
02:51:02,100 --> 02:51:03,100
generally the most common and sometimes
4040
02:51:04,319 --> 02:51:05,319
you might have light yellow or orange
4041
02:51:05,819 --> 02:51:06,819
for others now switch is forward traffic
4042
02:51:08,760 --> 02:51:09,760
to destination nodes via these ports on
4043
02:51:12,899 --> 02:51:13,899
the switch
4044
02:51:16,020 --> 02:51:17,020
and there might be as little as uh you
4045
02:51:18,300 --> 02:51:19,300
know a few ports maybe eight four or
4046
02:51:21,060 --> 02:51:22,060
even up to 168 or more now
4047
02:51:24,060 --> 02:51:25,060
administrators have the ability to do a
4048
02:51:25,979 --> 02:51:26,979
couple different things the first thing
4049
02:51:27,300 --> 02:51:28,300
they can do is do something called Port
4050
02:51:29,220 --> 02:51:30,220
mirroring
4051
02:51:30,479 --> 02:51:31,479
Port mirroring effectively
4052
02:51:33,479 --> 02:51:34,479
as the name implies
4053
02:51:37,319 --> 02:51:38,319
takes all the traffic on a specified
4054
02:51:39,720 --> 02:51:40,720
port and replicates it or copies it to
4055
02:51:43,020 --> 02:51:44,020
another port
4056
02:51:49,260 --> 02:51:50,260
now this is used for monitoring for
4057
02:51:52,380 --> 02:51:53,380
instance if I want to see what's going
4058
02:51:53,819 --> 02:51:54,819
on in a port but I don't want to stop
4059
02:51:55,380 --> 02:51:56,380
the traffic I can monitor this traffic
4060
02:51:57,600 --> 02:51:58,600
for analysis and diagnostic purposes
4061
02:52:00,000 --> 02:52:01,000
it's also going to allow administrators
4062
02:52:02,100 --> 02:52:03,100
to diagnose whether traffic across the
4063
02:52:04,560 --> 02:52:05,560
port is being interfered with by a
4064
02:52:06,600 --> 02:52:07,600
nefarious individual or someone who's
4065
02:52:08,640 --> 02:52:09,640
has a malicious intent such as a hacker
4066
02:52:11,460 --> 02:52:12,460
now if administrators want to combine
4067
02:52:14,580 --> 02:52:15,580
two or more network connections
4068
02:52:18,840 --> 02:52:19,840
it's called link aggregation
4069
02:52:27,080 --> 02:52:28,080
or Port teaming
4070
02:52:31,560 --> 02:52:32,560
and there are other names as well what
4071
02:52:34,200 --> 02:52:35,200
this does is this serves to increase or
4072
02:52:36,540 --> 02:52:37,540
effectively double the bandwidth uh as
4073
02:52:39,300 --> 02:52:40,300
well as allow for some redundancy
4074
02:52:41,040 --> 02:52:42,040
obviously or a backup connection or
4075
02:52:44,399 --> 02:52:45,399
something else another
4076
02:52:46,080 --> 02:52:47,080
name you might see this as by the way is
4077
02:52:48,720 --> 02:52:49,720
trunking
4078
02:52:50,100 --> 02:52:51,100
so that's the one I most see on the exam
4079
02:52:54,000 --> 02:52:55,000
so that's again taking two and sort of
4080
02:52:56,640 --> 02:52:57,640
treating them as one
4081
02:52:58,080 --> 02:52:59,080
finally we have something called Channel
4082
02:53:00,540 --> 02:53:01,540
bonding
4083
02:53:07,560 --> 02:53:08,560
which is the process of adding multiple
4084
02:53:10,080 --> 02:53:11,080
Nicks
4085
02:53:11,640 --> 02:53:12,640
to one
4086
02:53:17,640 --> 02:53:18,640
Mac address
4087
02:53:20,399 --> 02:53:21,399
this is also called Nick bonding and
4088
02:53:22,560 --> 02:53:23,560
we'll discuss it in Greater detail when
4089
02:53:24,120 --> 02:53:25,120
we're talking about IP addresses and
4090
02:53:26,399 --> 02:53:27,399
some of the other protocols
4091
02:53:29,580 --> 02:53:30,580
as opposed to a switch a router is a
4092
02:53:32,160 --> 02:53:33,160
connectivity device that typically
4093
02:53:34,140 --> 02:53:35,140
connects multiple networks or network
4094
02:53:36,420 --> 02:53:37,420
segments and unlike the switch it looks
4095
02:53:39,300 --> 02:53:40,300
at the IP address of each packet of data
4096
02:53:42,120 --> 02:53:43,120
to forward the to the destination node
4097
02:53:45,240 --> 02:53:46,240
so instead of the MAC address uh we're
4098
02:53:48,060 --> 02:53:49,060
looking at the IP address now a router
4099
02:53:51,660 --> 02:53:52,660
is usually used to connect networks that
4100
02:53:53,220 --> 02:53:54,220
use the same routable protocols so a
4101
02:53:56,640 --> 02:53:57,640
routable protocol is any protocol that
4102
02:53:59,460 --> 02:54:00,460
identifies the node
4103
02:54:04,680 --> 02:54:05,680
versus
4104
02:54:06,840 --> 02:54:07,840
the network
4105
02:54:11,640 --> 02:54:12,640
using
4106
02:54:13,740 --> 02:54:14,740
addressing
4107
02:54:16,380 --> 02:54:17,380
I.E the IP address now a router can be
4108
02:54:20,040 --> 02:54:21,040
installed as a hardware device as a
4109
02:54:22,740 --> 02:54:23,740
function of a multi-function device like
4110
02:54:24,840 --> 02:54:25,840
a Soho router
4111
02:54:28,520 --> 02:54:29,520
and uh it's also can be installed as
4112
02:54:32,040 --> 02:54:33,040
software in another device in a virtual
4113
02:54:34,020 --> 02:54:35,020
environment for instance on a server in
4114
02:54:36,420 --> 02:54:37,420
the case of a router being installed as
4115
02:54:38,340 --> 02:54:39,340
software in a virtual environment the
4116
02:54:41,100 --> 02:54:42,100
device or node has to have
4117
02:54:43,680 --> 02:54:44,680
two Nicks one Nick for the note itself
4118
02:54:45,960 --> 02:54:46,960
and then one Nick for the routing
4119
02:54:47,580 --> 02:54:48,580
functions sort of like one to go in and
4120
02:54:49,319 --> 02:54:50,319
one to go out a Gateway is a
4121
02:54:52,260 --> 02:54:53,260
connectivity device that's very much
4122
02:54:54,000 --> 02:54:55,000
like a router in the way it functions
4123
02:54:55,740 --> 02:54:56,740
and it routes traffic in much the same
4124
02:54:58,080 --> 02:54:59,080
way but the difference between a Gateway
4125
02:55:00,180 --> 02:55:01,180
and a router is that a Gateway connects
4126
02:55:02,220 --> 02:55:03,220
networks that have different protocols
4127
02:55:04,800 --> 02:55:05,800
or dissimilar protocols that to
4128
02:55:07,080 --> 02:55:08,080
communicate so the Gateway performs the
4129
02:55:09,479 --> 02:55:10,479
translation between
4130
02:55:11,600 --> 02:55:12,600
incompatible networks uh I'm just going
4131
02:55:14,640 --> 02:55:15,640
to put translation here since I think
4132
02:55:16,500 --> 02:55:17,500
that's pretty important
4133
02:55:21,080 --> 02:55:22,080
or
4134
02:55:22,740 --> 02:55:23,740
even different uh email systems or
4135
02:55:26,160 --> 02:55:27,160
operating systems now although it can be
4136
02:55:28,500 --> 02:55:29,500
easy to confuse a Gateway with the
4137
02:55:31,620 --> 02:55:32,620
default gateway that we see when we do
4138
02:55:33,720 --> 02:55:34,720
an ipconfig it's not the same thing
4139
02:55:44,160 --> 02:55:45,160
a Gateway is a device on the edge of the
4140
02:55:46,740 --> 02:55:47,740
network that's used to convert traffic
4141
02:55:49,319 --> 02:55:50,319
between different systems while as this
4142
02:55:51,720 --> 02:55:52,720
default gateway is simply forwards data
4143
02:55:54,899 --> 02:55:55,899
packets in TCP so we're going to discuss
4144
02:55:57,420 --> 02:55:58,420
that in more detail later but I just
4145
02:55:59,220 --> 02:56:00,220
want to point out this is not the
4146
02:56:00,540 --> 02:56:01,540
default gateway and just like a router
4147
02:56:04,020 --> 02:56:05,020
by the way it can be a hardware device
4148
02:56:05,939 --> 02:56:06,939
or software within a router or on
4149
02:56:08,640 --> 02:56:09,640
another virtual device and it uses
4150
02:56:11,100 --> 02:56:12,100
radical protocols that are similar to a
4151
02:56:13,380 --> 02:56:14,380
router but again it allows the
4152
02:56:15,359 --> 02:56:16,359
translation between different types of
4153
02:56:17,399 --> 02:56:18,399
protocols
4154
02:56:23,880 --> 02:56:24,880
now let's look at virtualization a bit
4155
02:56:26,340 --> 02:56:27,340
since this is really the the big thing
4156
02:56:28,319 --> 02:56:29,319
in Computing nowadays a virtual switch
4157
02:56:31,260 --> 02:56:32,260
for instance functions just like a
4158
02:56:34,140 --> 02:56:35,140
physical switch you cannot however
4159
02:56:36,300 --> 02:56:37,300
directly communicate between two virtual
4160
02:56:39,120 --> 02:56:40,120
switches if you want to do that you need
4161
02:56:41,160 --> 02:56:42,160
a virtual router or a router now a
4162
02:56:43,620 --> 02:56:44,620
Virtual Router is the software that can
4163
02:56:46,319 --> 02:56:47,319
be installed on a device with two nics
4164
02:56:48,420 --> 02:56:49,420
for routing traffic a virtual server is
4165
02:56:51,660 --> 02:56:52,660
a server that operates independently of
4166
02:56:53,939 --> 02:56:54,939
its host machine meaning that it's all
4167
02:56:57,120 --> 02:56:58,120
software based CPU Ram Etc can be
4168
02:57:00,120 --> 02:57:01,120
independent of its host machine whatever
4169
02:57:02,700 --> 02:57:03,700
that might be
4170
02:57:04,979 --> 02:57:05,979
now virtual machines uh are similar to a
4171
02:57:09,060 --> 02:57:10,060
virtual server in that it has its own
4172
02:57:11,279 --> 02:57:12,279
software like uh CPA based sorry
4173
02:57:14,100 --> 02:57:15,100
software based CPU Ram Nic hard drive
4174
02:57:16,800 --> 02:57:17,800
Etc but it's a software implementation
4175
02:57:18,840 --> 02:57:19,840
of a machine that performs specific
4176
02:57:21,000 --> 02:57:22,000
tasks and executes specific commands but
4177
02:57:24,120 --> 02:57:25,120
it's not a server per se all right
4178
02:57:26,939 --> 02:57:27,939
remember a server or something that's
4179
02:57:28,200 --> 02:57:29,200
serving up information to a client
4180
02:57:30,479 --> 02:57:31,479
and then finally we have a virtual
4181
02:57:32,040 --> 02:57:33,040
desktop which in Windows systems is a
4182
02:57:35,700 --> 02:57:36,700
single desktop
4183
02:57:38,520 --> 02:57:39,520
which in Windows systems a single
4184
02:57:40,740 --> 02:57:41,740
desktop
4185
02:57:42,300 --> 02:57:43,300
is the default that can be open but a
4186
02:57:45,120 --> 02:57:46,120
virtual desktop allows you to open
4187
02:57:47,040 --> 02:57:48,040
multiple different desktops at the same
4188
02:57:49,140 --> 02:57:50,140
time Linux also supports this by the way
4189
02:57:51,960 --> 02:57:52,960
but Microsoft requires extra software
4190
02:57:55,080 --> 02:57:56,080
that you install for this to be changed
4191
02:57:57,540 --> 02:57:58,540
for instance uh virtual PC
4192
02:58:00,420 --> 02:58:01,420
we've seen this if you remember with
4193
02:58:03,479 --> 02:58:04,479
um an A plus with XP Mode now continuing
4194
02:58:06,899 --> 02:58:07,899
to talk about virtualization if an
4195
02:58:09,479 --> 02:58:10,479
organization or a company builds their
4196
02:58:11,880 --> 02:58:12,880
Network infrastructure and chooses not
4197
02:58:14,700 --> 02:58:15,700
to use it they can lease it out to
4198
02:58:17,040 --> 02:58:18,040
others so for instance Amazon would be a
4199
02:58:19,859 --> 02:58:20,859
great example of this they have a huge
4200
02:58:21,660 --> 02:58:22,660
infrastructure but they don't use all of
4201
02:58:23,340 --> 02:58:24,340
it so what do they do they lease it out
4202
02:58:24,660 --> 02:58:25,660
to others this is a very common practice
4203
02:58:26,880 --> 02:58:27,880
and what it's labeled as is networking
4204
02:58:35,840 --> 02:58:36,840
as a service
4205
02:58:40,979 --> 02:58:41,979
now an area of network as a service or
4206
02:58:45,000 --> 02:58:46,000
Naas depending on what is being leased
4207
02:58:47,279 --> 02:58:48,279
might be considered one of several
4208
02:58:49,260 --> 02:58:50,260
different things it might be considered
4209
02:58:51,180 --> 02:58:52,180
IAS or infrastructure as a service
4210
02:58:55,680 --> 02:58:56,680
meaning like the hardware
4211
02:58:58,500 --> 02:58:59,500
I provide you the hardware provide you
4212
02:59:00,359 --> 02:59:01,359
the infrastructure it could be software
4213
02:59:02,939 --> 02:59:03,939
as a service much like Gmail
4214
02:59:08,399 --> 02:59:09,399
which simply provides you certain
4215
02:59:10,260 --> 02:59:11,260
software and just like infrastructure
4216
02:59:11,819 --> 02:59:12,819
would be like Amazon's uh
4217
02:59:14,760 --> 02:59:15,760
ec2 or elastic cloud and then the last
4218
02:59:19,380 --> 02:59:20,380
one is platform as a service
4219
02:59:21,960 --> 02:59:22,960
which would be like a an application
4220
02:59:24,420 --> 02:59:25,420
sort of engine or uh allowing you to
4221
02:59:27,859 --> 02:59:28,859
deploy certain
4222
02:59:29,880 --> 02:59:30,880
development tools most of the time
4223
02:59:32,340 --> 02:59:33,340
you're gonna see most of these in the
4224
02:59:34,500 --> 02:59:35,500
field this one is really more for
4225
02:59:37,319 --> 02:59:38,319
Developers
4226
02:59:43,560 --> 02:59:44,560
so the term Legacy indicates that this
4227
02:59:46,740 --> 02:59:47,740
is a an older device one that's not
4228
02:59:49,560 --> 02:59:50,560
really in use in today's networks or
4229
02:59:51,960 --> 02:59:52,960
that have been replaced by a newer or
4230
02:59:54,660 --> 02:59:55,660
higher functioning devices so some of
4231
02:59:56,880 --> 02:59:57,880
the things we're going to talk about in
4232
02:59:58,500 --> 02:59:59,500
this one might appear on the exam and
4233
03:00:00,359 --> 03:00:01,359
the reason the reason for that is
4234
03:00:02,279 --> 03:00:03,279
because they might appear in the field
4235
03:00:04,160 --> 03:00:05,160
uh just because they haven't been
4236
03:00:05,939 --> 03:00:06,939
replaced yet by perhaps due to expense
4237
03:00:08,100 --> 03:00:09,100
or something however these have probably
4238
03:00:10,920 --> 03:00:11,920
been replaced by switches routers and
4239
03:00:13,200 --> 03:00:14,200
gateways but it's still good to go over
4240
03:00:14,939 --> 03:00:15,939
them anyway so a repeater is a simple
4241
03:00:18,420 --> 03:00:19,420
device that does not look at the traffic
4242
03:00:20,939 --> 03:00:21,939
at all all it does is it simply boosts
4243
03:00:23,460 --> 03:00:24,460
the signal after it receives it and
4244
03:00:25,500 --> 03:00:26,500
transmits it out so it just repeats the
4245
03:00:28,080 --> 03:00:29,080
signal as the name implies just boosting
4246
03:00:31,080 --> 03:00:32,080
that signal we also have something
4247
03:00:32,640 --> 03:00:33,640
called a hub which you might have heard
4248
03:00:34,560 --> 03:00:35,560
of and this is similar to a repeater in
4249
03:00:37,319 --> 03:00:38,319
that it only it doesn't look at the data
4250
03:00:40,020 --> 03:00:41,020
it just retransmits it but the thing
4251
03:00:42,779 --> 03:00:43,779
that a Hub does is it receives traffic
4252
03:00:44,880 --> 03:00:45,880
from one port and sends it out to all
4253
03:00:47,580 --> 03:00:48,580
the ports without looking at the data
4254
03:00:49,500 --> 03:00:50,500
traffic now it's vastly been replaced by
4255
03:00:53,420 --> 03:00:54,420
switches because as you can imagine if I
4256
03:00:56,700 --> 03:00:57,700
wanted to send data to only one node The
4257
03:01:00,060 --> 03:01:01,060
Hub doesn't allow me to do that it makes
4258
03:01:01,439 --> 03:01:02,439
me send it to all of the nodes and so
4259
03:01:03,899 --> 03:01:04,899
this is going to cause quite a bit of
4260
03:01:05,279 --> 03:01:06,279
extra traffic on my network finally
4261
03:01:08,279 --> 03:01:09,279
there's something called a bridge which
4262
03:01:10,920 --> 03:01:11,920
was the purpose was to divide logical
4263
03:01:14,100 --> 03:01:15,100
bus networks into segments and it did
4264
03:01:16,380 --> 03:01:17,380
this by looking at the MAC address so it
4265
03:01:18,420 --> 03:01:19,420
is operating it's sort of the same level
4266
03:01:20,580 --> 03:01:21,580
as a as a switch and it would look at
4267
03:01:23,279 --> 03:01:24,279
the MAC address of the packet and
4268
03:01:24,660 --> 03:01:25,660
transmitted the data accordingly now if
4269
03:01:26,939 --> 03:01:27,939
the MAC address was on another segment
4270
03:01:28,979 --> 03:01:29,979
it forwarded it out and if the
4271
03:01:31,020 --> 03:01:32,020
destination was on the same segment then
4272
03:01:32,880 --> 03:01:33,880
it didn't forward it so in older
4273
03:01:35,220 --> 03:01:36,220
networks this implementation was logical
4274
03:01:37,979 --> 03:01:38,979
and it was handy because it reduced
4275
03:01:40,260 --> 03:01:41,260
traffic congestion and improved
4276
03:01:42,420 --> 03:01:43,420
performance obviously because it wasn't
4277
03:01:44,040 --> 03:01:45,040
forwarding data that didn't need to be
4278
03:01:46,200 --> 03:01:47,200
forwarded on
4279
03:01:47,700 --> 03:01:48,700
all right now let's talk about noise
4280
03:01:49,399 --> 03:01:50,399
noise or electrical noise and networking
4281
03:01:52,319 --> 03:01:53,319
it's the term that interferes with uh
4282
03:01:57,000 --> 03:01:58,000
implies rather interfering with data uh
4283
03:02:00,720 --> 03:02:01,720
and normal data traffic it can come from
4284
03:02:04,380 --> 03:02:05,380
many sources and as Network
4285
03:02:05,819 --> 03:02:06,819
administrators it's really important
4286
03:02:07,439 --> 03:02:08,439
that we know where all this noise is
4287
03:02:10,020 --> 03:02:11,020
coming from and how to prevent it as
4288
03:02:11,939 --> 03:02:12,939
well so not only can noise affect our
4289
03:02:14,160 --> 03:02:15,160
network uh performance but it can also
4290
03:02:16,859 --> 03:02:17,859
affect data transmission electrical
4291
03:02:19,260 --> 03:02:20,260
current as well now if electrical
4292
03:02:21,240 --> 03:02:22,240
current is interrupted or interfered
4293
03:02:23,160 --> 03:02:24,160
with then that can affect our electrical
4294
03:02:26,220 --> 03:02:27,220
devices so for instance if there is a
4295
03:02:28,560 --> 03:02:29,560
surge in the current that means a lot of
4296
03:02:30,840 --> 03:02:31,840
extraneous noise in the electrical line
4297
03:02:32,520 --> 03:02:33,520
goes to our devices and then damages
4298
03:02:34,740 --> 03:02:35,740
them so sources of noise are found in
4299
03:02:37,200 --> 03:02:38,200
many places as you see here is a power
4300
03:02:39,479 --> 03:02:40,479
line electric motors used in HVAC
4301
03:02:42,600 --> 03:02:43,600
systems elevators refrigerators just
4302
03:02:45,840 --> 03:02:46,840
about anything that draws power to run
4303
03:02:48,000 --> 03:02:49,000
fluorescent lights neon or height
4304
03:02:50,819 --> 03:02:51,819
intensity discharge lights or what are
4305
03:02:53,399 --> 03:02:54,399
called HID lights uh also cause
4306
03:02:57,060 --> 03:02:58,060
significant amounts of noise that
4307
03:02:59,399 --> 03:03:00,399
interfere with networking over both
4308
03:03:01,560 --> 03:03:02,560
bounded and unbounded media this is
4309
03:03:04,620 --> 03:03:05,620
especially important to be mindful of
4310
03:03:06,240 --> 03:03:07,240
when you're running or installing your
4311
03:03:07,920 --> 03:03:08,920
cables or placing your wireless access
4312
03:03:09,960 --> 03:03:10,960
points you want to really avoid running
4313
03:03:12,120 --> 03:03:13,120
data cable parallel to those lights as
4314
03:03:15,180 --> 03:03:16,180
well as any cables used for power it can
4315
03:03:18,060 --> 03:03:19,060
also come from devices that give off
4316
03:03:19,920 --> 03:03:20,920
heat like personal heating devices and
4317
03:03:22,500 --> 03:03:23,500
while that might sound a little strange
4318
03:03:23,880 --> 03:03:24,880
it's due to the amount of power that
4319
03:03:25,319 --> 03:03:26,319
those devices consume when in use the
4320
03:03:27,899 --> 03:03:28,899
power or the electricity it has the
4321
03:03:29,760 --> 03:03:30,760
potential to give off a lot of noise
4322
03:03:31,140 --> 03:03:32,140
which makes sense now lastly normal
4323
03:03:33,720 --> 03:03:34,720
ambient noise also called background
4324
03:03:36,240 --> 03:03:37,240
noise or the noise that's present due to
4325
03:03:39,120 --> 03:03:40,120
atmospheric conditions like solar
4326
03:03:41,160 --> 03:03:42,160
disturbances radio broadcasting towers
4327
03:03:43,500 --> 03:03:44,500
that are nearby Etc the main thing to
4328
03:03:46,200 --> 03:03:47,200
consider with ambient noise is the
4329
03:03:47,520 --> 03:03:48,520
distance or the the length of your media
4330
03:03:49,500 --> 03:03:50,500
the longer your media run is the closer
4331
03:03:52,260 --> 03:03:53,260
to its maximum rated length then the
4332
03:03:54,720 --> 03:03:55,720
more susceptible your signal is going to
4333
03:03:57,479 --> 03:03:58,479
be so to combat this we one thing we can
4334
03:04:00,420 --> 03:04:01,420
do is called grounding which is a method
4335
03:04:03,180 --> 03:04:04,180
of taking the shielding or a conductor
4336
03:04:06,240 --> 03:04:07,240
and connecting it to an electrical
4337
03:04:08,580 --> 03:04:09,580
ground point that is directly in content
4338
03:04:11,279 --> 03:04:12,279
with literally the Earth's ground now
4339
03:04:13,439 --> 03:04:14,439
when we connect a network segment at one
4340
03:04:15,899 --> 03:04:16,899
point to a ground this basically shunts
4341
03:04:18,960 --> 03:04:19,960
or drains the extraneous noise
4342
03:04:22,160 --> 03:04:23,160
only leaving the data signal so at the
4343
03:04:27,359 --> 03:04:28,359
same time if more than one point is
4344
03:04:29,640 --> 03:04:30,640
grounded this can introduce even more
4345
03:04:31,979 --> 03:04:32,979
noise which is going to greatly reduce
4346
03:04:33,779 --> 03:04:34,779
the quality of the signal if not even
4347
03:04:35,939 --> 03:04:36,939
completely get rid of it so we can only
4348
03:04:38,399 --> 03:04:39,399
we only want to uh ground the point uh
4349
03:04:41,880 --> 03:04:42,880
once which is important if we do it more
4350
03:04:44,040 --> 03:04:45,040
than once we're going to be in major
4351
03:04:45,240 --> 03:04:46,240
trouble not only do we ground for
4352
03:04:46,979 --> 03:04:47,979
Network for a performer but we also do
4353
03:04:49,140 --> 03:04:50,140
it for safety because most electrical
4354
03:04:51,840 --> 03:04:52,840
devices have to be grounded in one way
4355
03:04:53,460 --> 03:04:54,460
or the other otherwise you know we just
4356
03:04:56,160 --> 03:04:57,160
like we saw with a plus and touching
4357
03:04:58,380 --> 03:04:59,380
devices if we don't ground something we
4358
03:05:00,600 --> 03:05:01,600
could possibly damage it this is mostly
4359
03:05:03,300 --> 03:05:04,300
to redirect uh High voltages
4360
03:05:07,500 --> 03:05:08,500
into the ground where they're not going
4361
03:05:09,180 --> 03:05:10,180
to harm your equipment now electricians
4362
03:05:11,819 --> 03:05:12,819
have special ground points or dedicated
4363
03:05:14,040 --> 03:05:15,040
ground points that are designed
4364
03:05:15,740 --> 03:05:16,740
specifically for sensitive electrical
4365
03:05:18,300 --> 03:05:19,300
equipment these isolated grounds they're
4366
03:05:21,060 --> 03:05:22,060
def they're usually going to be colored
4367
03:05:22,800 --> 03:05:23,800
orange which helps differentiate them
4368
03:05:24,960 --> 03:05:25,960
from normal plugs so if you see an
4369
03:05:27,479 --> 03:05:28,479
orange looking plug that is a special uh
4370
03:05:30,960 --> 03:05:31,960
isolated ground
4371
03:05:32,700 --> 03:05:33,700
now the shielding around a cable as you
4372
03:05:35,040 --> 03:05:36,040
can see here on this coaxial cable
4373
03:05:37,800 --> 03:05:38,800
um is a noise prevention measure that
4374
03:05:40,439 --> 03:05:41,439
takes the noise and drains it through
4375
03:05:42,479 --> 03:05:43,479
the shielding away from the conductor in
4376
03:05:45,060 --> 03:05:46,060
the center that is carrying the draining
4377
03:05:47,160 --> 03:05:48,160
the the data traffic now the shielding
4378
03:05:49,920 --> 03:05:50,920
is then connected to a single ground
4379
03:05:52,080 --> 03:05:53,080
Point flushing the noise away the
4380
03:05:55,080 --> 03:05:56,080
connection between the shield and the
4381
03:05:56,819 --> 03:05:57,819
ground point is also called the drain
4382
03:05:59,279 --> 03:06:00,279
which is why we say it's grain drain and
4383
03:06:02,279 --> 03:06:03,279
this same thing doesn't just go for
4384
03:06:03,600 --> 03:06:04,600
coaxial it also goes for STP or shielded
4385
03:06:06,779 --> 03:06:07,779
twisted pair as well now because the
4386
03:06:09,180 --> 03:06:10,180
noise is often going to be constant the
4387
03:06:12,359 --> 03:06:13,359
method of differential signaling takes
4388
03:06:15,359 --> 03:06:16,359
two received signals
4389
03:06:17,220 --> 03:06:18,220
and subtracts the equal signals
4390
03:06:21,359 --> 03:06:22,359
which is typically going to be the noise
4391
03:06:22,859 --> 03:06:23,859
of the noise floor and that's going to
4392
03:06:25,140 --> 03:06:26,140
give us an end result of Simply the
4393
03:06:28,319 --> 03:06:29,319
noise so basically it takes this signal
4394
03:06:30,420 --> 03:06:31,420
input which is a digital input signal
4395
03:06:32,279 --> 03:06:33,279
and
4396
03:06:34,080 --> 03:06:35,080
it takes that subtracts this
4397
03:06:37,560 --> 03:06:38,560
and then we can get
4398
03:06:39,740 --> 03:06:40,740
a a signal without any noise in it as
4399
03:06:43,500 --> 03:06:44,500
you can see
4400
03:06:46,680 --> 03:06:47,680
now besides differential signaling there
4401
03:06:49,020 --> 03:06:50,020
are also a few other noise control
4402
03:06:50,160 --> 03:06:51,160
considerations we talked about earlier
4403
03:06:52,500 --> 03:06:53,500
something called termination which is
4404
03:06:54,300 --> 03:06:55,300
really important in networking some
4405
03:06:56,640 --> 03:06:57,640
cables require termination to be
4406
03:06:59,040 --> 03:07:00,040
installed at the end of either uh
4407
03:07:03,180 --> 03:07:04,180
the end of either
4408
03:07:04,800 --> 03:07:05,800
connection right if you remember that
4409
03:07:07,260 --> 03:07:08,260
from our bus and it has to have the
4410
03:07:09,840 --> 03:07:10,840
appropriate ohm rating
4411
03:07:13,800 --> 03:07:14,800
if you install the Terminator and it
4412
03:07:16,380 --> 03:07:17,380
doesn't have that proper ohm rating then
4413
03:07:18,479 --> 03:07:19,479
it's probably going to
4414
03:07:20,279 --> 03:07:21,279
um uh actually
4415
03:07:22,680 --> 03:07:23,680
it won't work effectively now luckily
4416
03:07:25,080 --> 03:07:26,080
for us in most cases the Terminators are
4417
03:07:27,300 --> 03:07:28,300
installed in these network devices by
4418
03:07:29,040 --> 03:07:30,040
default but not too long ago you had to
4419
03:07:31,560 --> 03:07:32,560
install them manually and you had to
4420
03:07:33,000 --> 03:07:34,000
make sure the impedance or the amount of
4421
03:07:34,680 --> 03:07:35,680
ohms was matched it was a fairly simple
4422
03:07:37,560 --> 03:07:38,560
task but the specific impedance could
4423
03:07:41,760 --> 03:07:42,760
have been marked on a cable jacket or if
4424
03:07:44,760 --> 03:07:45,760
a large amount of cable was installed it
4425
03:07:46,740 --> 03:07:47,740
just added another step to the process
4426
03:07:49,020 --> 03:07:50,020
now something else to keep in mind is
4427
03:07:50,819 --> 03:07:51,819
how you run the cable your cable run you
4428
03:07:53,100 --> 03:07:54,100
don't want to run data cable and
4429
03:07:54,359 --> 03:07:55,359
electrical cable in the same tray and
4430
03:07:56,520 --> 03:07:57,520
you should try to avoid running your
4431
03:07:58,140 --> 03:07:59,140
data cable parallel to any electrical
4432
03:08:00,120 --> 03:08:01,120
cables or any other data cables in order
4433
03:08:02,340 --> 03:08:03,340
to reduce what's called a crosstalk
4434
03:08:04,979 --> 03:08:05,979
which basically means the signal sort of
4435
03:08:07,020 --> 03:08:08,020
jumps from one to the other
4436
03:08:08,700 --> 03:08:09,700
now if you keep data cables away from
4437
03:08:10,800 --> 03:08:11,800
Motors fluorescent lighting high power
4438
03:08:13,140 --> 03:08:14,140
devices like we saw you owe and you
4439
03:08:15,899 --> 03:08:16,899
always ground your electrical equipment
4440
03:08:17,460 --> 03:08:18,460
and electrical circuits according to the
4441
03:08:19,680 --> 03:08:20,680
manufacturer and you allow for uh all
4442
03:08:23,040 --> 03:08:24,040
the recommended installation
4443
03:08:24,060 --> 03:08:25,060
requirements and grounding requirements
4444
03:08:25,859 --> 03:08:26,859
that they provide then you should be
4445
03:08:27,720 --> 03:08:28,720
good to go when you're connecting your
4446
03:08:29,100 --> 03:08:30,100
cables together and when you're um
4447
03:08:31,680 --> 03:08:32,680
running your cables as well so just to
4448
03:08:34,680 --> 03:08:35,680
recap what we've talked about here first
4449
03:08:36,420 --> 03:08:37,420
we looked at a Nick and a network or a
4450
03:08:39,660 --> 03:08:40,660
network interface card
4451
03:08:48,240 --> 03:08:49,240
foreign
4452
03:08:48,960 --> 03:08:49,960
we describe the transceiver something
4453
03:08:51,120 --> 03:08:52,120
that goes on the card and how it
4454
03:08:53,399 --> 03:08:54,399
functions we also looked at identifying
4455
03:08:56,160 --> 03:08:57,160
the characteristics of a switch which if
4456
03:08:58,439 --> 03:08:59,439
you remember use Mac addressing we
4457
03:09:01,080 --> 03:09:02,080
defined trunking Port mirroring and
4458
03:09:03,300 --> 03:09:04,300
channel bonding remember trunking was
4459
03:09:05,520 --> 03:09:06,520
using two or more ports as though they
4460
03:09:07,740 --> 03:09:08,740
were one port mirroring usually going to
4461
03:09:10,260 --> 03:09:11,260
use for Diagnostic purposes and then
4462
03:09:13,140 --> 03:09:14,140
Channel bonding which is uh sort of
4463
03:09:15,359 --> 03:09:16,359
bonding those Nicks together we also
4464
03:09:17,460 --> 03:09:18,460
described a router and a Gateway which
4465
03:09:19,620 --> 03:09:20,620
again operate with IP addresses instead
4466
03:09:22,020 --> 03:09:23,020
of Max and they allow us whereas
4467
03:09:24,240 --> 03:09:25,240
switches allow us to work within a lan
4468
03:09:26,760 --> 03:09:27,760
IP addresses or rather routers allow us
4469
03:09:29,399 --> 03:09:30,399
and gateways to operate within a Wan or
4470
03:09:31,800 --> 03:09:32,800
a wide area network finally we looked at
4471
03:09:34,020 --> 03:09:35,020
some Legacy devices and we defined noise
4472
03:09:37,260 --> 03:09:38,260
and the sources of noise including any
4473
03:09:39,779 --> 03:09:40,779
of those high power devices and then we
4474
03:09:41,819 --> 03:09:42,819
looked at some noise control and
4475
03:09:43,140 --> 03:09:44,140
reduction techniques including proper
4476
03:09:45,300 --> 03:09:46,300
grounding and
4477
03:09:47,939 --> 03:09:48,939
shielding
4478
03:09:54,970 --> 03:09:55,970
[Music]
4479
03:10:11,819 --> 03:10:12,819
so welcome to module 2 lesson 4 new
4480
03:10:15,300 --> 03:10:16,300
topic added to the CompTIA syllabus the
4481
03:10:20,160 --> 03:10:21,160
um what is the syllabus number the below
4482
03:10:22,500 --> 03:10:23,500
seven
4483
03:10:25,560 --> 03:10:26,560
um Advanced networking devices so this
4484
03:10:27,420 --> 03:10:28,420
is stuff that we need to be aware of
4485
03:10:29,279 --> 03:10:30,279
because it becomes a prominence may have
4486
03:10:31,800 --> 03:10:32,800
been in the industry a while but
4487
03:10:35,399 --> 03:10:36,399
um now in regular use or big ubiquitous
4488
03:10:38,880 --> 03:10:39,880
as they say
4489
03:10:40,560 --> 03:10:41,560
so Advanced networking devices Network
4490
03:10:42,600 --> 03:10:43,600
Hardware media I'm going to look at
4491
03:10:44,279 --> 03:10:45,279
multi-layer switches
4492
03:10:46,080 --> 03:10:47,080
wireless controllers a load balancer
4493
03:10:49,500 --> 03:10:50,500
IDs and IPS
4494
03:10:52,979 --> 03:10:53,979
we're going to look at AAA and radio
4495
03:10:55,200 --> 03:10:56,200
server I think that's dotted throughout
4496
03:10:57,420 --> 03:10:58,420
the syllabus so we pick it up as a
4497
03:11:01,200 --> 03:11:02,200
security subject and also an advanced
4498
03:11:03,120 --> 03:11:04,120
networking device
4499
03:11:05,160 --> 03:11:06,160
uh UTM Next Generation firewalls Veep
4500
03:11:10,319 --> 03:11:11,319
Gateway and in terms of PBX that is uh
4501
03:11:14,340 --> 03:11:15,340
content filter so this is one of the I
4502
03:11:17,700 --> 03:11:18,700
think it's the first device actually
4503
03:11:18,899 --> 03:11:19,899
that Cisco ever
4504
03:11:20,880 --> 03:11:21,880
um brought to Market is known as the
4505
03:11:24,300 --> 03:11:25,300
um the Cisco pretty hard to see there it
4506
03:11:26,819 --> 03:11:27,819
was the AGS uh husband and wife uh first
4507
03:11:30,600 --> 03:11:31,600
artist Cisco and I think they had a
4508
03:11:32,040 --> 03:11:33,040
colleague that they used to work with
4509
03:11:33,899 --> 03:11:34,899
and
4510
03:11:35,460 --> 03:11:36,460
um
4511
03:11:36,660 --> 03:11:37,660
they actually bought
4512
03:11:38,939 --> 03:11:39,939
um the first Cisco switch was actually
4513
03:11:40,979 --> 03:11:41,979
created by a company called a kaplana or
4514
03:11:44,279 --> 03:11:45,279
kalpana if you pronounce it this was
4515
03:11:47,100 --> 03:11:48,100
their very first ever switch and um
4516
03:11:49,319 --> 03:11:50,319
switches used to run some old uh code I
4517
03:11:52,859 --> 03:11:53,859
think something like um
4518
03:11:54,899 --> 03:11:55,899
I think we used to call it
4519
03:11:57,180 --> 03:11:58,180
katos and then the routers well there
4520
03:12:01,140 --> 03:12:02,140
was no code
4521
03:12:02,340 --> 03:12:03,340
um that they because they created it
4522
03:12:03,960 --> 03:12:04,960
they created their own code
4523
03:12:06,060 --> 03:12:07,060
and that's called the internet work
4524
03:12:08,460 --> 03:12:09,460
operating system Cisco brought the whole
4525
03:12:10,740 --> 03:12:11,740
thing together now so there's this you
4526
03:12:12,240 --> 03:12:13,240
don't have to use the old command line
4527
03:12:14,580 --> 03:12:15,580
that work for katos but they they just
4528
03:12:16,680 --> 03:12:17,680
weren't compatible at all
4529
03:12:18,600 --> 03:12:19,600
so you had to kind of learn how to
4530
03:12:20,220 --> 03:12:21,220
program two different type of devices
4531
03:12:22,680 --> 03:12:23,680
so this was the early I think this is
4532
03:12:24,899 --> 03:12:25,899
from The Cisco Museum actually and
4533
03:12:28,020 --> 03:12:29,020
um you can see the Cabana switch up here
4534
03:12:30,600 --> 03:12:31,600
so a real old-fashioned connectors uh
4535
03:12:35,040 --> 03:12:36,040
maybe the db25s you can see there's no
4536
03:12:37,680 --> 03:12:38,680
high speed connections here massive
4537
03:12:39,960 --> 03:12:40,960
switch and then your power connector
4538
03:12:42,660 --> 03:12:43,660
yeah so I'm sure this is Cutting Edge
4539
03:12:45,420 --> 03:12:46,420
when it first came out huge thing in the
4540
03:12:48,180 --> 03:12:49,180
1990s but when you're supporting
4541
03:12:51,300 --> 03:12:52,300
networks back then
4542
03:12:53,640 --> 03:12:54,640
really um there wasn't an awful lot to
4543
03:12:55,920 --> 03:12:56,920
it a server router a hub there wasn't
4544
03:12:59,640 --> 03:13:00,640
that much traffic because people
4545
03:13:01,140 --> 03:13:02,140
couldn't afford the kit anyway
4546
03:13:03,420 --> 03:13:04,420
um early 90s the web was invented I'm
4547
03:13:06,479 --> 03:13:07,479
sure most people weren't really using it
4548
03:13:07,979 --> 03:13:08,979
ethernet was running at 10 Meg half
4549
03:13:10,560 --> 03:13:11,560
duplex
4550
03:13:12,479 --> 03:13:13,479
a Cisco the early 90s had 251 employees
4551
03:13:16,859 --> 03:13:17,859
obviously there were just I think three
4552
03:13:18,660 --> 03:13:19,660
people to start and they grew to 251.
4553
03:13:22,800 --> 03:13:23,800
and then scroll forwards to the current
4554
03:13:25,939 --> 03:13:26,939
ERA and you can see obviously things are
4555
03:13:28,800 --> 03:13:29,800
a lot more complicated
4556
03:13:31,380 --> 03:13:32,380
we have a multi-lay devices working at
4557
03:13:34,500 --> 03:13:35,500
seven different layers of the OSI model
4558
03:13:37,260 --> 03:13:38,260
incorporate Wireless into our Networks
4559
03:13:40,740 --> 03:13:41,740
recover Wireless later
4560
03:13:42,899 --> 03:13:43,899
there isn't anywhere you go now really
4561
03:13:44,760 --> 03:13:45,760
where there isn't somebody offering some
4562
03:13:46,140 --> 03:13:47,140
sort of wireless connection
4563
03:13:48,359 --> 03:13:49,359
virtualization is a Hot Topic
4564
03:13:50,939 --> 03:13:51,939
and it's obviously used by pretty much
4565
03:13:53,279 --> 03:13:54,279
all of the cloud providers Amazon Google
4566
03:13:56,660 --> 03:13:57,660
and Microsoft to
4567
03:14:00,180 --> 03:14:01,180
um cut costs and improve performance
4568
03:14:03,300 --> 03:14:04,300
cloud computing is a red hot topic that
4569
03:14:05,880 --> 03:14:06,880
I encourage everyone to learn video
4570
03:14:08,100 --> 03:14:09,100
voice over IP and quality of service you
4571
03:14:11,520 --> 03:14:12,520
need to be aware of advanced security
4572
03:14:13,140 --> 03:14:14,140
threats and obviously the larger the
4573
03:14:15,600 --> 03:14:16,600
network now they'll have their own
4574
03:14:16,859 --> 03:14:17,859
dedicated security team for Hardware
4575
03:14:19,560 --> 03:14:20,560
software and
4576
03:14:21,540 --> 03:14:22,540
um
4577
03:14:22,760 --> 03:14:23,760
protecting from employees and that kind
4578
03:14:25,200 --> 03:14:26,200
of thing Cisco currently has 72 000
4579
03:14:29,100 --> 03:14:30,100
employees I know when I worked there
4580
03:14:31,620 --> 03:14:32,620
when was it the early 90s they were
4581
03:14:34,020 --> 03:14:35,020
getting rid of slaves of different
4582
03:14:36,540 --> 03:14:37,540
employees from the legal team and
4583
03:14:38,520 --> 03:14:39,520
marketing teams and some Engineers as
4584
03:14:40,380 --> 03:14:41,380
well so I'm not sure if it was ever
4585
03:14:42,060 --> 03:14:43,060
higher than that but as stated on the
4586
03:14:44,939 --> 03:14:45,939
interweb it's 72 000. this is quite a
4587
03:14:47,819 --> 03:14:48,819
lot
4588
03:14:49,439 --> 03:14:50,439
so what are the devices that's mentioned
4589
03:14:52,560 --> 03:14:53,560
now brought into the syllabus is the
4590
03:14:54,120 --> 03:14:55,120
multi-layer switch
4591
03:14:55,460 --> 03:14:56,460
switch is generally a layer two switch
4592
03:14:58,439 --> 03:14:59,439
is which is the cheaper models will
4593
03:15:00,240 --> 03:15:01,240
switch frames at Layer Two and they'll
4594
03:15:03,420 --> 03:15:04,420
lay they'll use hardware for this
4595
03:15:05,580 --> 03:15:06,580
multi-layer switches operate layers two
4596
03:15:08,819 --> 03:15:09,819
to seven you can buy a switch operates
4597
03:15:10,319 --> 03:15:11,319
at layers two three four or another
4598
03:15:12,300 --> 03:15:13,300
switch and you can see here
4599
03:15:14,939 --> 03:15:15,939
I might be clear but the this is
4600
03:15:17,399 --> 03:15:18,399
actually uh a connection bracket here
4601
03:15:20,220 --> 03:15:21,220
and what happens is this is a switch in
4602
03:15:22,979 --> 03:15:23,979
module
4603
03:15:24,180 --> 03:15:25,180
that you can buy and Slot into the
4604
03:15:27,240 --> 03:15:28,240
chassis so what you could have there
4605
03:15:29,580 --> 03:15:30,580
instead is uh there's two
4606
03:15:33,960 --> 03:15:34,960
um modules here and depending on what
4607
03:15:36,300 --> 03:15:37,300
you buy you could have one here for
4608
03:15:37,859 --> 03:15:38,859
voice one here for remote connections
4609
03:15:39,899 --> 03:15:40,899
you could have a mini switching module
4610
03:15:42,060 --> 03:15:43,060
here or one that's only dedicated for
4611
03:15:44,460 --> 03:15:45,460
voice connections you can see actually
4612
03:15:46,979 --> 03:15:47,979
these are exactly the same and it looks
4613
03:15:49,200 --> 03:15:50,200
like there's USB there if you um connect
4614
03:15:51,240 --> 03:15:52,240
in management interfaces a console
4615
03:15:54,359 --> 03:15:55,359
connection
4616
03:15:55,620 --> 03:15:56,620
and there's what there's one two three
4617
03:15:59,819 --> 03:16:00,819
four switching modules here and it looks
4618
03:16:02,520 --> 03:16:03,520
like it's got Quad Power as well so if
4619
03:16:06,000 --> 03:16:07,000
anything goes wrong with the power
4620
03:16:08,279 --> 03:16:09,279
supplies you've got
4621
03:16:10,740 --> 03:16:11,740
three
4622
03:16:12,140 --> 03:16:13,140
uh possible power supplies I'm not sure
4623
03:16:15,660 --> 03:16:16,660
they're probably going to be hot
4624
03:16:16,800 --> 03:16:17,800
swappable and I'm not sure if they're
4625
03:16:18,420 --> 03:16:19,420
working
4626
03:16:19,439 --> 03:16:20,439
uh there's one's a backup four two and
4627
03:16:22,859 --> 03:16:23,859
um fours are back up for three and vice
4628
03:16:24,600 --> 03:16:25,600
versa you have to check the
4629
03:16:26,040 --> 03:16:27,040
documentation but this whole chassis
4630
03:16:28,500 --> 03:16:29,500
would obviously be connected into the
4631
03:16:31,080 --> 03:16:32,080
cabinet here and you can probably have
4632
03:16:33,660 --> 03:16:34,660
um one major switch here and then a
4633
03:16:36,300 --> 03:16:37,300
second one to take up um the whole rack
4634
03:16:39,180 --> 03:16:40,180
so multi-layer switches operate
4635
03:16:42,380 --> 03:16:43,380
multiple layers from two to seven
4636
03:16:45,240 --> 03:16:46,240
bandwidth can be up to several gigahertz
4637
03:16:48,420 --> 03:16:49,420
and you can stack Cisco switches so they
4638
03:16:50,580 --> 03:16:51,580
all become one you could have two or
4639
03:16:52,200 --> 03:16:53,200
three switches or becoming one logical
4640
03:16:54,479 --> 03:16:55,479
switch
4641
03:16:55,740 --> 03:16:56,740
and ports can be switched which is Mac
4642
03:16:58,200 --> 03:16:59,200
address a MAC address in or you can
4643
03:17:00,779 --> 03:17:01,779
configure them to be a layer 3 port and
4644
03:17:04,380 --> 03:17:05,380
Route IP addresses
4645
03:17:06,660 --> 03:17:07,660
and I think that's outside the syllabus
4646
03:17:08,580 --> 03:17:09,580
how to actually configure it
4647
03:17:11,819 --> 03:17:12,819
um so this would be your typical layer 2
4648
03:17:13,740 --> 03:17:14,740
switch now if you wanted to uh route so
4649
03:17:17,040 --> 03:17:18,040
if these devices down here on VLAN 20
4650
03:17:20,100 --> 03:17:21,100
you can see they're on
4651
03:17:22,100 --> 03:17:23,100
192.168.20 well that's not a different
4652
03:17:25,220 --> 03:17:26,220
subnet to one on two one six eight ten
4653
03:17:28,620 --> 03:17:29,620
so this would be host uh one and two for
4654
03:17:32,399 --> 03:17:33,399
example on that subnet and this would be
4655
03:17:34,620 --> 03:17:35,620
host one and two on that subnet well the
4656
03:17:39,180 --> 03:17:40,180
only way because this is working at
4657
03:17:40,859 --> 03:17:41,859
Layer Two the only way to Route because
4658
03:17:44,279 --> 03:17:45,279
we're we're dealing with layer two layer
4659
03:17:47,279 --> 03:17:48,279
3 here and so all layer 2 traffic this
4660
03:17:51,000 --> 03:17:52,000
switch would take care of in its Mac
4661
03:17:53,279 --> 03:17:54,279
table which we've covered earlier now if
4662
03:17:55,740 --> 03:17:56,740
you wanted a route then
4663
03:17:58,200 --> 03:17:59,200
um traditionally you would have to send
4664
03:18:00,779 --> 03:18:01,779
out the packet to the router the router
4665
03:18:04,620 --> 03:18:05,620
has a directory of all the networks 10
4666
03:18:07,560 --> 03:18:08,560
20. this network 30 will probably be for
4667
03:18:10,800 --> 03:18:11,800
foreign
4668
03:18:13,880 --> 03:18:14,880
management traffic or it could be
4669
03:18:16,319 --> 03:18:17,319
whatever you want
4670
03:18:17,520 --> 03:18:18,520
and then it would route and then it
4671
03:18:20,040 --> 03:18:21,040
would decide that it needs to send that
4672
03:18:22,080 --> 03:18:23,080
traffic out it could be an interface or
4673
03:18:24,120 --> 03:18:25,120
a sub interface
4674
03:18:25,740 --> 03:18:26,740
this is uh what's known as a
4675
03:18:28,580 --> 03:18:29,580
router on a
4676
03:18:34,460 --> 03:18:35,460
stick one armed router or router on a
4677
03:18:37,740 --> 03:18:38,740
stick and unfortunately they have the
4678
03:18:39,359 --> 03:18:40,359
physical cable
4679
03:18:41,000 --> 03:18:42,000
uh will carry all the traffic coming in
4680
03:18:43,740 --> 03:18:44,740
and out not a great way to run your
4681
03:18:46,020 --> 03:18:47,020
network I mean it's okay if you're in a
4682
03:18:48,060 --> 03:18:49,060
small business and nobody would notice
4683
03:18:49,680 --> 03:18:50,680
but this is carrying all your bandwidth
4684
03:18:51,960 --> 03:18:52,960
and obviously this is a um single point
4685
03:18:55,680 --> 03:18:56,680
of failure here this cable breaks all
4686
03:18:58,680 --> 03:18:59,680
this interface
4687
03:19:00,180 --> 03:19:01,180
or this interface then you can't Route
4688
03:19:03,479 --> 03:19:04,479
traffic the only traffic that would then
4689
03:19:06,359 --> 03:19:07,359
pass would be
4690
03:19:08,340 --> 03:19:09,340
um with it within the um VLAN sorry
4691
03:19:11,580 --> 03:19:12,580
uh he couldn't be couldn't pass this
4692
03:19:13,260 --> 03:19:14,260
traffic
4693
03:19:14,220 --> 03:19:15,220
so this is a multi-layer switch
4694
03:19:18,240 --> 03:19:19,240
so call it
4695
03:19:19,859 --> 03:19:20,859
um say layer 3 switch
4696
03:19:22,800 --> 03:19:23,800
and what happens is as you've seen
4697
03:19:24,779 --> 03:19:25,779
you've got the modules that are slotted
4698
03:19:26,640 --> 03:19:27,640
in here the more you pay the more
4699
03:19:28,920 --> 03:19:29,920
options you have obviously and this
4700
03:19:31,200 --> 03:19:32,200
module
4701
03:19:33,660 --> 03:19:34,660
here is for switching so you've got all
4702
03:19:36,779 --> 03:19:37,779
your ethernet connections and this could
4703
03:19:39,180 --> 03:19:40,180
be your routing module and so all
4704
03:19:42,120 --> 03:19:43,120
contained within the same chassis and
4705
03:19:44,460 --> 03:19:45,460
the technology isn't really covered in
4706
03:19:46,200 --> 03:19:47,200
the syllabus but it would switch the uh
4707
03:19:48,840 --> 03:19:49,840
traffic depending if it's Layer Two or
4708
03:19:51,720 --> 03:19:52,720
layer 3 within the same unit so
4709
03:19:54,420 --> 03:19:55,420
basically what you don't have to have is
4710
03:19:57,060 --> 03:19:58,060
this device here and this device here
4711
03:19:59,819 --> 03:20:00,819
it's all within the same unit and
4712
03:20:02,160 --> 03:20:03,160
depending on what you spend this could
4713
03:20:03,720 --> 03:20:04,720
be
4714
03:20:04,560 --> 03:20:05,560
um doing access lists on also your
4715
03:20:07,200 --> 03:20:08,200
connection out to the internet depending
4716
03:20:09,600 --> 03:20:10,600
on how how much money you have and what
4717
03:20:11,640 --> 03:20:12,640
your requirements are
4718
03:20:14,399 --> 03:20:15,399
uh next device is a wireless controller
4719
03:20:17,220 --> 03:20:18,220
this is a Cisco 2500 Cisco wireless
4720
03:20:19,859 --> 03:20:20,859
controller
4721
03:20:21,479 --> 03:20:22,479
has the cheaper devices you've probably
4722
03:20:24,000 --> 03:20:25,000
seen you probably got one at home here
4723
03:20:26,340 --> 03:20:27,340
is your wireless access points and what
4724
03:20:30,000 --> 03:20:31,000
happens is you've got a few um wireless
4725
03:20:32,520 --> 03:20:33,520
access points probably say this is your
4726
03:20:35,279 --> 03:20:36,279
office
4727
03:20:37,979 --> 03:20:38,979
and normally these would take care of
4728
03:20:39,899 --> 03:20:40,899
all of the connections what happens is
4729
03:20:42,300 --> 03:20:43,300
these become lightweight access points
4730
03:20:45,479 --> 03:20:46,479
in as much as all they're doing is
4731
03:20:48,180 --> 03:20:49,180
taking in all of the signals and then
4732
03:20:51,120 --> 03:20:52,120
passing it over to this master device
4733
03:20:54,359 --> 03:20:55,359
obviously it costs a bit more and so
4734
03:20:57,300 --> 03:20:58,300
these are lightwork access points and
4735
03:20:58,800 --> 03:20:59,800
this is your wireless LAN controller
4736
03:21:01,500 --> 03:21:02,500
which some people refer to as wlc
4737
03:21:06,060 --> 03:21:07,060
so it allows your wireless devices to
4738
03:21:08,700 --> 03:21:09,700
communicate and you can see you've got
4739
03:21:10,140 --> 03:21:11,140
some wired connections there as well
4740
03:21:12,840 --> 03:21:13,840
takes over from the access points
4741
03:21:15,540 --> 03:21:16,540
becoming lightweight forwarders so you'd
4742
03:21:18,120 --> 03:21:19,120
have to throw them away which is Handy
4743
03:21:20,520 --> 03:21:21,520
the wireless access controller has your
4744
03:21:23,700 --> 03:21:24,700
service set ID it can have logical
4745
03:21:26,220 --> 03:21:27,220
interfaces and as you can see down here
4746
03:21:28,800 --> 03:21:29,800
you've got physical pause for ethernet
4747
03:21:30,840 --> 03:21:31,840
and when you first buy it if you want to
4748
03:21:34,220 --> 03:21:35,220
you can connect to the console Port here
4749
03:21:37,380 --> 03:21:38,380
and then use your PC to set it up to
4750
03:21:41,100 --> 03:21:42,100
whatever
4751
03:21:41,939 --> 03:21:42,939
um parameters you want and also you can
4752
03:21:43,920 --> 03:21:44,920
use this port here for Disaster Recovery
4753
03:21:46,500 --> 03:21:47,500
you obviously have to be physically
4754
03:21:48,180 --> 03:21:49,180
present unless you connect a Cisco
4755
03:21:52,439 --> 03:21:53,439
access server which we'll cover later
4756
03:21:54,660 --> 03:21:55,660
which um that would have an internet
4757
03:21:56,399 --> 03:21:57,399
connection out here so you could
4758
03:21:59,279 --> 03:22:00,279
um and if you said tile Nets probably
4759
03:22:00,660 --> 03:22:01,660
ssh in through
4760
03:22:03,779 --> 03:22:04,779
um here and then you could from the from
4761
03:22:06,359 --> 03:22:07,359
this um
4762
03:22:07,439 --> 03:22:08,439
Cisco access over here
4763
03:22:09,960 --> 03:22:10,960
you would have a connection going into
4764
03:22:11,399 --> 03:22:12,399
your console Port but we'll cover that
4765
03:22:13,260 --> 03:22:14,260
later
4766
03:22:14,399 --> 03:22:15,399
uh ports can be switched uh so they're
4767
03:22:17,220 --> 03:22:18,220
just dealing with Mac addresses or they
4768
03:22:18,899 --> 03:22:19,899
can be configured to route
4769
03:22:21,000 --> 03:22:22,000
depending on what you need
4770
03:22:22,859 --> 03:22:23,859
so your wireless controllers these your
4771
03:22:25,500 --> 03:22:26,500
wireless LAN controllers permit mobile
4772
03:22:27,300 --> 03:22:28,300
devices to Rome roaming means keeping
4773
03:22:31,200 --> 03:22:32,200
the same IP address
4774
03:22:33,840 --> 03:22:34,840
now you can have intra controller
4775
03:22:35,700 --> 03:22:36,700
roaming so you've just got one
4776
03:22:37,560 --> 03:22:38,560
controller or you can have inter control
4777
03:22:39,779 --> 03:22:40,779
around me which is a little bit more
4778
03:22:41,279 --> 03:22:42,279
difficult but as you're walking through
4779
03:22:43,800 --> 03:22:44,800
your say you're in a coffee shop
4780
03:22:47,460 --> 03:22:48,460
and you've got
4781
03:22:49,979 --> 03:22:50,979
ground floor here and say there's a
4782
03:22:52,439 --> 03:22:53,439
concrete which normally is as a concrete
4783
03:22:54,779 --> 03:22:55,779
floor and you go up the stairs look at
4784
03:22:57,660 --> 03:22:58,660
my amazing stairs there and
4785
03:23:01,020 --> 03:23:02,020
you're in the uh first floor I know you
4786
03:23:04,979 --> 03:23:05,979
I think you don't have a ground floor in
4787
03:23:06,600 --> 03:23:07,600
America maybe the first floor it's
4788
03:23:08,160 --> 03:23:09,160
called the first floor but on the ground
4789
03:23:09,899 --> 03:23:10,899
in the UK we call it ground floor and
4790
03:23:11,580 --> 03:23:12,580
then first and so on what you don't want
4791
03:23:13,739 --> 03:23:14,739
to have to do is reassociate with a new
4792
03:23:16,920 --> 03:23:17,920
uh controller so basically you'd have to
4793
03:23:19,620 --> 03:23:20,620
connect to
4794
03:23:21,660 --> 03:23:22,660
um
4795
03:23:22,739 --> 03:23:23,739
wireless network one and wireless
4796
03:23:25,380 --> 03:23:26,380
network too you don't really want that
4797
03:23:27,479 --> 03:23:28,479
you want to go in
4798
03:23:29,220 --> 03:23:30,220
connect to their free wireless and then
4799
03:23:32,100 --> 03:23:33,100
keep
4800
03:23:33,080 --> 03:23:34,080
your IP address so
4801
03:23:39,080 --> 03:23:40,080
172.168.1.1 so keep it as you're roaming
4802
03:23:41,760 --> 03:23:42,760
around the building
4803
03:23:43,020 --> 03:23:44,020
if you're just using lightweight access
4804
03:23:44,700 --> 03:23:45,700
points then you would have to just keep
4805
03:23:47,100 --> 03:23:48,100
reassociating which in this day and age
4806
03:23:49,620 --> 03:23:50,620
is obviously a pain because we're so
4807
03:23:51,779 --> 03:23:52,779
lazy so I've mentioned intra controller
4808
03:23:54,359 --> 03:23:55,359
and Inter controller you can see in the
4809
03:23:56,220 --> 03:23:57,220
diagrams there
4810
03:23:58,800 --> 03:23:59,800
the load balancer
4811
03:24:01,620 --> 03:24:02,620
so this distributes incoming requests
4812
03:24:04,260 --> 03:24:05,260
between two or more devices so your this
4813
03:24:07,380 --> 03:24:08,380
is trans this will be transparent
4814
03:24:14,760 --> 03:24:15,760
so what your clients think is happening
4815
03:24:19,500 --> 03:24:20,500
is basically it thinks this is happening
4816
03:24:24,300 --> 03:24:25,300
it doesn't realize that this device is
4817
03:24:26,279 --> 03:24:27,279
here which is fine by us as Network
4818
03:24:28,680 --> 03:24:29,680
Engineers will will take care of that
4819
03:24:31,140 --> 03:24:32,140
and what it will do is balance so it
4820
03:24:33,300 --> 03:24:34,300
will take uh the say the first
4821
03:24:35,460 --> 03:24:36,460
connection here
4822
03:24:38,040 --> 03:24:39,040
and then oh no this is getting really
4823
03:24:40,260 --> 03:24:41,260
bad now
4824
03:24:41,520 --> 03:24:42,520
it will log internally here and then
4825
03:24:45,600 --> 03:24:46,600
this could be
4826
03:24:46,859 --> 03:24:47,859
a network or just the device
4827
03:24:50,399 --> 03:24:51,399
third connection here and it will
4828
03:24:52,140 --> 03:24:53,140
balance
4829
03:24:53,819 --> 03:24:54,819
and you don't have a single point of
4830
03:24:55,739 --> 03:24:56,739
failure so your third connection goes
4831
03:24:57,720 --> 03:24:58,720
here this load hits uh say 90 percent
4832
03:25:03,420 --> 03:25:04,420
but this server it could be a higher
4833
03:25:05,580 --> 03:25:06,580
powered server it doesn't have to be the
4834
03:25:07,260 --> 03:25:08,260
same this is only sitting at twenty
4835
03:25:09,420 --> 03:25:10,420
percent
4836
03:25:10,319 --> 03:25:11,319
then it will route more of the traffic
4837
03:25:12,420 --> 03:25:13,420
to here if this goes down for whatever
4838
03:25:14,880 --> 03:25:15,880
reason transparent to all the end hosts
4839
03:25:17,399 --> 03:25:18,399
it will load balance between these two
4840
03:25:20,880 --> 03:25:21,880
and you can um you could be routing
4841
03:25:24,300 --> 03:25:25,300
between different devices it doesn't
4842
03:25:25,620 --> 03:25:26,620
have to be servers
4843
03:25:28,739 --> 03:25:29,739
so you can balance web traffic streaming
4844
03:25:31,020 --> 03:25:32,020
videos databases whatever you so wish
4845
03:25:33,660 --> 03:25:34,660
now the IP address is actually sitting
4846
03:25:37,200 --> 03:25:38,200
on here
4847
03:25:38,520 --> 03:25:39,520
so say uh 12.1.1.1
4848
03:25:43,380 --> 03:25:44,380
and then these will have probably have
4849
03:25:46,020 --> 03:25:47,020
non-routable addresses so RFC 1918
4850
03:25:50,279 --> 03:25:51,279
addresses which is
4851
03:25:53,120 --> 03:25:54,120
whatever you know the the
4852
03:25:56,040 --> 03:25:57,040
private IP address is
4853
03:25:58,380 --> 03:25:59,380
but we won't care about that as
4854
03:26:00,000 --> 03:26:01,000
customers moving on IDs and IPS
4855
03:26:04,560 --> 03:26:05,560
uh Cisco Market leaders in this type of
4856
03:26:06,960 --> 03:26:07,960
equipment
4857
03:26:08,520 --> 03:26:09,520
uh I can't see what the model number is
4858
03:26:10,939 --> 03:26:11,939
4240. always great to serve the sales
4859
03:26:14,340 --> 03:26:15,340
pages for all of these vendors
4860
03:26:17,399 --> 03:26:18,399
uh Cisco and Juniper and whoever because
4861
03:26:20,700 --> 03:26:21,700
it gives you lots of useful
4862
03:26:22,080 --> 03:26:23,080
documentation you can see what's
4863
03:26:23,520 --> 03:26:24,520
available
4864
03:26:24,540 --> 03:26:25,540
now both of these do the same job they
4865
03:26:26,580 --> 03:26:27,580
inspect traffic to detect unauthorized
4866
03:26:29,220 --> 03:26:30,220
access
4867
03:26:30,359 --> 03:26:31,359
and monitors the network for intrusions
4868
03:26:32,220 --> 03:26:33,220
or malicious activities now what it can
4869
03:26:34,859 --> 03:26:35,859
do is send an alert which is
4870
03:26:38,399 --> 03:26:39,399
um oh no I'm gonna have to draw a
4871
03:26:41,640 --> 03:26:42,640
this is actually a a telephone I hope
4872
03:26:44,580 --> 03:26:45,580
you impress old-fashioned telephone
4873
03:26:46,260 --> 03:26:47,260
there if you recognize that then you're
4874
03:26:48,660 --> 03:26:49,660
officially old so you could send a
4875
03:26:51,660 --> 03:26:52,660
message to your mobile phone it can send
4876
03:26:55,520 --> 03:26:56,520
SMS log messages whatever you so wish or
4877
03:26:59,460 --> 03:27:00,460
an SNMP trap and that will
4878
03:27:02,399 --> 03:27:03,399
um it could shut down a port or whatever
4879
03:27:04,020 --> 03:27:05,020
you instruct it to do
4880
03:27:06,540 --> 03:27:07,540
now IPS Works in line so it's placed in
4881
03:27:09,420 --> 03:27:10,420
the traffic flow so you've got internet
4882
03:27:12,739 --> 03:27:13,739
and I'll stick it here actually
4883
03:27:16,620 --> 03:27:17,620
your IPS and then that will go off to
4884
03:27:20,220 --> 03:27:21,220
your
4885
03:27:21,540 --> 03:27:22,540
router
4886
03:27:23,420 --> 03:27:24,420
switch and then your your hosts here
4887
03:27:27,779 --> 03:27:28,779
however many hosts you've got
4888
03:27:31,439 --> 03:27:32,439
and I don't give up your day job so this
4889
03:27:33,600 --> 03:27:34,600
is in line your traffic will come
4890
03:27:35,220 --> 03:27:36,220
through here it'll be inspected and then
4891
03:27:37,680 --> 03:27:38,680
go to your end device the IDS is not in
4892
03:27:42,899 --> 03:27:43,899
line
4893
03:27:44,040 --> 03:27:45,040
so what will happen is router
4894
03:27:48,660 --> 03:27:49,660
switch
4895
03:27:53,399 --> 03:27:54,399
host and it can be put here or here I'll
4896
03:27:56,580 --> 03:27:57,580
say there's an ethernet connection here
4897
03:27:59,939 --> 03:28:00,939
now your IDs receives a copy of the
4898
03:28:03,180 --> 03:28:04,180
frame so the frame I'll call it frame
4899
03:28:07,319 --> 03:28:08,319
um frame y
4900
03:28:09,600 --> 03:28:10,600
and then
4901
03:28:10,920 --> 03:28:11,920
that is just a copy because frame Y is
4902
03:28:13,979 --> 03:28:14,979
actually being passed through to your
4903
03:28:16,859 --> 03:28:17,859
switch obviously you can see the problem
4904
03:28:18,660 --> 03:28:19,660
here is receiving a copy but this
4905
03:28:21,239 --> 03:28:22,239
traffic is actually going through your
4906
03:28:23,279 --> 03:28:24,279
network so
4907
03:28:24,960 --> 03:28:25,960
these are less common now the RDS is
4908
03:28:29,040 --> 03:28:30,040
I'm going to talk about these later in
4909
03:28:31,800 --> 03:28:32,800
the security sections AAA or radius and
4910
03:28:35,700 --> 03:28:36,700
used for authentication to validate the
4911
03:28:38,460 --> 03:28:39,460
identity does a few things actually and
4912
03:28:40,680 --> 03:28:41,680
um Josh talked about the different
4913
03:28:42,420 --> 03:28:43,420
aspects of AAA earlier authorization
4914
03:28:45,720 --> 03:28:46,720
determines what you can do and
4915
03:28:48,180 --> 03:28:49,180
accounting is for the audit Trail so
4916
03:28:50,520 --> 03:28:51,520
this um the accountant will normally go
4917
03:28:52,380 --> 03:28:53,380
off to a server where you can
4918
03:28:54,359 --> 03:28:55,359
interrogate the server logs and
4919
03:28:57,600 --> 03:28:58,600
sometimes you need to do it for
4920
03:28:59,640 --> 03:29:00,640
um compliance
4921
03:29:04,160 --> 03:29:05,160
or um
4922
03:29:06,720 --> 03:29:07,720
if you're going to legally
4923
03:29:08,819 --> 03:29:09,819
take a case against somebody
4924
03:29:11,700 --> 03:29:12,700
so it's a modular and scalable model for
4925
03:29:14,040 --> 03:29:15,040
network and device access you can run it
4926
03:29:16,380 --> 03:29:17,380
on its own server or certainly in the
4927
03:29:19,200 --> 03:29:20,200
terms of Cisco you can have the server
4928
03:29:21,960 --> 03:29:22,960
software running on your router and
4929
03:29:23,399 --> 03:29:24,399
switch probably not recommended because
4930
03:29:25,739 --> 03:29:26,739
routers are designed specifically to
4931
03:29:28,080 --> 03:29:29,080
Route traffic
4932
03:29:30,540 --> 03:29:31,540
uses radius attack ax plus and curb Ross
4933
03:29:33,779 --> 03:29:34,779
as authentication methods don't I don't
4934
03:29:35,760 --> 03:29:36,760
think airbrush is actually in the
4935
03:29:37,080 --> 03:29:38,080
syllabus but I know a radius attack ax
4936
03:29:40,680 --> 03:29:41,680
is certainly worth looking at the
4937
03:29:43,439 --> 03:29:44,439
CompTIA Security Plus which we go into a
4938
03:29:46,200 --> 03:29:47,200
lot more detail in this stuff
4939
03:29:48,120 --> 03:29:49,120
I've already mentioned using the service
4940
03:29:50,520 --> 03:29:51,520
uh UTM is an appliance
4941
03:29:53,580 --> 03:29:54,580
integrates a range of security features
4942
03:29:55,800 --> 03:29:56,800
but it does it into a single Appliance a
4943
03:29:58,260 --> 03:29:59,260
while ago actually I was when I was
4944
03:30:00,620 --> 03:30:01,620
Consulting in the early
4945
03:30:03,260 --> 03:30:04,260
2003 there was one company in particular
4946
03:30:06,899 --> 03:30:07,899
brought out everything in a box bearing
4947
03:30:09,359 --> 03:30:10,359
in mind the needs weren't as complicated
4948
03:30:11,040 --> 03:30:12,040
back then so this box
4949
03:30:14,279 --> 03:30:15,279
let's say boxer server we do your um
4950
03:30:18,720 --> 03:30:19,720
email it would do your web
4951
03:30:22,140 --> 03:30:23,140
it would get you out to the internet as
4952
03:30:26,520 --> 03:30:27,520
well and then it would obviously connect
4953
03:30:29,460 --> 03:30:30,460
off to your
4954
03:30:30,840 --> 03:30:31,840
switch and I think it also had your
4955
03:30:36,140 --> 03:30:37,140
firewall there's a few things it did but
4956
03:30:38,939 --> 03:30:39,939
basically this was everything in a box
4957
03:30:40,439 --> 03:30:41,439
that a small business would need
4958
03:30:42,899 --> 03:30:43,899
so it does several things and it's
4959
03:30:45,660 --> 03:30:46,660
designed to do them all pretty well your
4960
03:30:47,340 --> 03:30:48,340
firewall your antivirus your IDs or IPS
4961
03:30:50,220 --> 03:30:51,220
you can it has VPN software built in
4962
03:30:53,180 --> 03:30:54,180
brands that you want to check out that
4963
03:30:55,439 --> 03:30:56,439
are Market leaders at the moment are so
4964
03:30:57,180 --> 03:30:58,180
fast which this is a copyright from
4965
03:31:00,300 --> 03:31:01,300
their page
4966
03:31:01,979 --> 03:31:02,979
and why jungle
4967
03:31:04,140 --> 03:31:05,140
a lot easier for you to install and
4968
03:31:06,960 --> 03:31:07,960
manage most of it will be running off
4969
03:31:08,880 --> 03:31:09,880
the graphical user interface so rather
4970
03:31:11,580 --> 03:31:12,580
than have to configure a Cisco device
4971
03:31:13,439 --> 03:31:14,439
which is frankly quite a nightmare for
4972
03:31:15,960 --> 03:31:16,960
most people unless you know what you're
4973
03:31:17,580 --> 03:31:18,580
doing
4974
03:31:19,859 --> 03:31:20,859
uh it just makes it a lot easier
4975
03:31:21,840 --> 03:31:22,840
probably I'm I'm saying it's more
4976
03:31:24,000 --> 03:31:25,000
suitable for the check the software
4977
03:31:26,040 --> 03:31:27,040
because they may say different the small
4978
03:31:28,200 --> 03:31:29,200
business the small to medium-sized
4979
03:31:31,020 --> 03:31:32,020
Enterprise where you don't have a lot of
4980
03:31:32,640 --> 03:31:33,640
employees and you may just have one
4981
03:31:34,680 --> 03:31:35,680
support person or somebody that comes in
4982
03:31:36,660 --> 03:31:37,660
just to do patches and maintenance
4983
03:31:40,439 --> 03:31:41,439
obviously saves time and money so a big
4984
03:31:43,859 --> 03:31:44,859
pull for any small businesses
4985
03:31:46,620 --> 03:31:47,620
the only problem is if you're running
4986
03:31:48,600 --> 03:31:49,600
everything off this I guess it's running
4987
03:31:50,640 --> 03:31:51,640
off a server of some sort because it's
4988
03:31:53,220 --> 03:31:54,220
software based then you've got a single
4989
03:31:55,260 --> 03:31:56,260
point of failure so you've got to take
4990
03:31:56,760 --> 03:31:57,760
this
4991
03:31:57,840 --> 03:31:58,840
um into account with your business
4992
03:31:59,520 --> 03:32:00,520
continuity planning what you're going to
4993
03:32:01,380 --> 03:32:02,380
do if it part of it breaks all of it
4994
03:32:04,080 --> 03:32:05,080
breaks
4995
03:32:05,160 --> 03:32:06,160
Etc
4996
03:32:06,500 --> 03:32:07,500
ngfw Next Generation firewalls so the
4997
03:32:09,960 --> 03:32:10,960
hackers as you know are getting smarter
4998
03:32:11,939 --> 03:32:12,939
and smarter and smarter and whereas and
4999
03:32:15,000 --> 03:32:16,000
we'd have to be checking the IP headers
5000
03:32:17,880 --> 03:32:18,880
or the TCP headers to find any malicious
5001
03:32:21,000 --> 03:32:22,000
code it's actually now being buried
5002
03:32:24,239 --> 03:32:25,239
inside the application data and
5003
03:32:26,939 --> 03:32:27,939
traditionally your firewalls May well
5004
03:32:29,279 --> 03:32:30,279
have been just checking these particular
5005
03:32:31,560 --> 03:32:32,560
Fields headers Footers trailers whatever
5006
03:32:34,859 --> 03:32:35,859
so I just got this image off um this URL
5007
03:32:37,979 --> 03:32:38,979
here so these are known as third
5008
03:32:40,080 --> 03:32:41,080
generation firewalls
5009
03:32:43,200 --> 03:32:44,200
this combines your firewall with your
5010
03:32:45,540 --> 03:32:46,540
other filtering looking at application
5011
03:32:47,819 --> 03:32:48,819
and this is where the crypto lockers are
5012
03:32:50,819 --> 03:32:51,819
hiding which we cover later
5013
03:32:53,939 --> 03:32:54,939
and it can include antivirus ID
5014
03:32:56,399 --> 03:32:57,399
management your transport layer security
5015
03:32:58,620 --> 03:32:59,620
which is the latest version so secure
5016
03:33:02,819 --> 03:33:03,819
sockets layer quality of service if
5017
03:33:04,859 --> 03:33:05,859
you're running it on your network so if
5018
03:33:06,600 --> 03:33:07,600
you're trying to prioritize Voice or
5019
03:33:09,840 --> 03:33:10,840
video conferencing whatever you want to
5020
03:33:11,760 --> 03:33:12,760
run at your work
5021
03:33:14,279 --> 03:33:15,279
uh command firewall antivirus Gateway
5022
03:33:16,819 --> 03:33:17,819
IDs IPS VPN software
5023
03:33:21,600 --> 03:33:22,600
now eighty percent of the malware now
5024
03:33:24,479 --> 03:33:25,479
targets your application so this is
5025
03:33:28,140 --> 03:33:29,140
this is the software stuff and normally
5026
03:33:31,020 --> 03:33:32,020
we wouldn't have been inspecting inside
5027
03:33:32,960 --> 03:33:33,960
this part of the packet but this is
5028
03:33:35,640 --> 03:33:36,640
where they're hiding it now and so you
5029
03:33:37,620 --> 03:33:38,620
might things that have been downloaded
5030
03:33:39,300 --> 03:33:40,300
off the websites or in hidden inside
5031
03:33:41,760 --> 03:33:42,760
emails so this is why we need this third
5032
03:33:44,160 --> 03:33:45,160
generation of firewall
5033
03:33:47,580 --> 03:33:48,580
so blocking ports and filtering is no
5034
03:33:50,460 --> 03:33:51,460
longer enough unfortunately so I mean
5035
03:33:52,620 --> 03:33:53,620
just um Gathering more data spending
5036
03:33:54,600 --> 03:33:55,600
more cash and having more stuff to
5037
03:33:56,399 --> 03:33:57,399
support what this is known as here is
5038
03:33:59,040 --> 03:34:00,040
deep packet inspection DPI so we're
5039
03:34:02,100 --> 03:34:03,100
looking deep inside the IP pack here to
5040
03:34:04,560 --> 03:34:05,560
see if there's anything nefarious in
5041
03:34:06,180 --> 03:34:07,180
there
5042
03:34:08,279 --> 03:34:09,279
the Deepak inspection you can see things
5043
03:34:10,800 --> 03:34:11,800
that you wouldn't normally see looking
5044
03:34:12,060 --> 03:34:13,060
at the headers and Footers and trailers
5045
03:34:15,180 --> 03:34:16,180
worms viruses and it can also do so most
5046
03:34:18,600 --> 03:34:19,600
importantly at wire speeds so the thing
5047
03:34:21,720 --> 03:34:22,720
that we all hate in networks is
5048
03:34:25,920 --> 03:34:26,920
latency I.E slowing stuff down it's
5049
03:34:29,340 --> 03:34:30,340
really bad news for us and it obviously
5050
03:34:30,720 --> 03:34:31,720
frustrates the users especially if
5051
03:34:32,580 --> 03:34:33,580
you're doing voice and video
5052
03:34:33,540 --> 03:34:34,540
conferencing it would be a nightmare
5053
03:34:37,500 --> 03:34:38,500
they've added a voiceover voice over IP
5054
03:34:40,439 --> 03:34:41,439
PBX into the syllabus
5055
03:34:45,899 --> 03:34:46,899
and you can see we've got the voice
5056
03:34:47,939 --> 03:34:48,939
Gateway router here I've got this from
5057
03:34:49,859 --> 03:34:50,859
this website here easytalks.com so
5058
03:34:52,439 --> 03:34:53,439
you've got your uh public switch
5059
03:34:54,479 --> 03:34:55,479
telephone Network which Josh talked
5060
03:34:56,460 --> 03:34:57,460
about which is your voice stuff and then
5061
03:34:59,160 --> 03:35:00,160
we've got our traditional phones uh
5062
03:35:01,800 --> 03:35:02,800
we've got our IP phones been managed
5063
03:35:04,020 --> 03:35:05,020
here so we can all communicate within
5064
03:35:05,700 --> 03:35:06,700
each other and then your voice PBX if
5065
03:35:09,540 --> 03:35:10,540
you need to make calls to traditional
5066
03:35:11,100 --> 03:35:12,100
landlines that can go out through the
5067
03:35:13,439 --> 03:35:14,439
traditional public switch Network
5068
03:35:17,399 --> 03:35:18,399
so IP private Branch exchange is a phone
5069
03:35:19,979 --> 03:35:20,979
system and it but it also offers IP
5070
03:35:22,200 --> 03:35:23,200
connectivity you get your traditional
5071
03:35:24,420 --> 03:35:25,420
extensions connecting through your Lan
5072
03:35:26,640 --> 03:35:27,640
and obviously you can go through
5073
03:35:28,859 --> 03:35:29,859
the internet if you've got your
5074
03:35:31,340 --> 03:35:32,340
traditional IP phone and you want to
5075
03:35:34,020 --> 03:35:35,020
call somebody in the remote office with
5076
03:35:36,120 --> 03:35:37,120
another IP phone
5077
03:35:38,040 --> 03:35:39,040
and you can do that okay otherwise it
5078
03:35:40,800 --> 03:35:41,800
would have to go through to the public
5079
03:35:41,939 --> 03:35:42,939
switch telephone Network
5080
03:35:44,160 --> 03:35:45,160
you can buy actually software so it'll
5081
03:35:46,380 --> 03:35:47,380
run off a server if you so wish or you
5082
03:35:48,420 --> 03:35:49,420
can have a hardware where you have to
5083
03:35:49,979 --> 03:35:50,979
wire it up yourself
5084
03:35:51,720 --> 03:35:52,720
mentioned it connects to the phone
5085
03:35:53,580 --> 03:35:54,580
network and obviously use it if invoice
5086
03:35:56,460 --> 03:35:57,460
is enabled on your network
5087
03:35:59,580 --> 03:36:00,580
content filters
5088
03:36:02,460 --> 03:36:03,460
uh what you can and can't uh Surf and
5089
03:36:06,540 --> 03:36:07,540
I've got something similar on my home
5090
03:36:08,160 --> 03:36:09,160
router although the Fairly rudimental
5091
03:36:10,439 --> 03:36:11,439
level where I can block stuff that and
5092
03:36:13,020 --> 03:36:14,020
the kids shouldn't be watching also
5093
03:36:15,300 --> 03:36:16,300
referred to as information filtering
5094
03:36:18,000 --> 03:36:19,000
depending on where you are usually
5095
03:36:19,920 --> 03:36:20,920
software based and it's it's very simply
5096
03:36:23,340 --> 03:36:24,340
blocks harmful websites or files such as
5097
03:36:26,160 --> 03:36:27,160
Dot xees
5098
03:36:27,660 --> 03:36:28,660
it would probably uh block
5099
03:36:30,300 --> 03:36:31,300
um Facebook
5100
03:36:34,800 --> 03:36:35,800
Instagram stuff you don't want people
5101
03:36:36,660 --> 03:36:37,660
surfing while they're at work also
5102
03:36:39,840 --> 03:36:40,840
you can work your local network so your
5103
03:36:45,060 --> 03:36:46,060
um
5104
03:36:45,660 --> 03:36:46,660
office here you could actually have it
5105
03:36:48,420 --> 03:36:49,420
working for your core Network
5106
03:36:52,279 --> 03:36:53,279
or you could let your ISP take care take
5107
03:36:55,500 --> 03:36:56,500
care of it sometimes they're actually
5108
03:36:57,479 --> 03:36:58,479
automatically block
5109
03:36:59,460 --> 03:37:00,460
and certain content and certain websites
5110
03:37:01,859 --> 03:37:02,859
especially in some countries where they
5111
03:37:04,260 --> 03:37:05,260
they control politically what you can
5112
03:37:06,600 --> 03:37:07,600
and can't say I think um
5113
03:37:10,200 --> 03:37:11,200
Egypt and some other countries where
5114
03:37:12,660 --> 03:37:13,660
they don't want you to see certain
5115
03:37:14,340 --> 03:37:15,340
things
5116
03:37:15,660 --> 03:37:16,660
which I won't go into that uh so your
5117
03:37:19,080 --> 03:37:20,080
voice is enabled sorry that's uh but
5118
03:37:21,120 --> 03:37:22,120
they're in error from another slide
5119
03:37:23,399 --> 03:37:24,399
so multi-layer switch we've talked about
5120
03:37:25,439 --> 03:37:26,439
your wireless controllers turning your
5121
03:37:29,100 --> 03:37:30,100
access points into lightweight access
5122
03:37:32,819 --> 03:37:33,819
points so they just forward traffic and
5123
03:37:35,880 --> 03:37:36,880
your wireless LAN controller takes care
5124
03:37:37,859 --> 03:37:38,859
of all of the routing security
5125
03:37:40,819 --> 03:37:41,819
associations
5126
03:37:43,160 --> 03:37:44,160
ssids that kind of stuff
5127
03:37:46,020 --> 03:37:47,020
load balancer where it's sending your
5128
03:37:49,020 --> 03:37:50,020
traffic transparently to two or more
5129
03:37:53,220 --> 03:37:54,220
servers and obviously it's got your
5130
03:37:56,580 --> 03:37:57,580
um
5131
03:37:57,420 --> 03:37:58,420
the capability of if there's a one of
5132
03:37:59,640 --> 03:38:00,640
your servers goes down it can balance
5133
03:38:01,020 --> 03:38:02,020
between what uh or others are left
5134
03:38:04,680 --> 03:38:05,680
RDS on IPS uh you've got to bear in mind
5135
03:38:07,620 --> 03:38:08,620
what's in line and then what is out of
5136
03:38:11,340 --> 03:38:12,340
line and just receives a copy because
5137
03:38:13,260 --> 03:38:14,260
that's your typical exam question
5138
03:38:17,880 --> 03:38:18,880
AAA server which I'll talk more about
5139
03:38:20,040 --> 03:38:21,040
later uh UTM again probably small
5140
03:38:24,960 --> 03:38:25,960
to medium-sized Enterprise but do check
5141
03:38:27,660 --> 03:38:28,660
the marketing spiel
5142
03:38:29,880 --> 03:38:30,880
Next Generation firewall which is deep
5143
03:38:33,960 --> 03:38:34,960
packet inspections voice
5144
03:38:37,319 --> 03:38:38,319
again if you're going out to the
5145
03:38:40,319 --> 03:38:41,319
public switch telephone Network you'll
5146
03:38:42,840 --> 03:38:43,840
need the voice Gateway contact content
5147
03:38:45,420 --> 03:38:46,420
filter is blocking sites or content
5148
03:38:49,140 --> 03:38:50,140
definitely dot XC files
5149
03:38:52,760 --> 03:38:53,760
and um even even my online file that I
5150
03:38:58,080 --> 03:38:59,080
share with my providers some of my
5151
03:39:00,600 --> 03:39:01,600
Freelancers that work for me they can't
5152
03:39:02,760 --> 03:39:03,760
reach this on them from their corporate
5153
03:39:06,000 --> 03:39:07,000
Network either they're often blocked
5154
03:39:08,100 --> 03:39:09,100
all right so that's all for now thank
5155
03:39:09,840 --> 03:39:10,840
you very much for listening
5156
03:39:14,030 --> 03:39:15,030
[Music]
5157
03:39:33,720 --> 03:39:34,720
foreign network communications data
5158
03:39:37,560 --> 03:39:38,560
transmission
5159
03:39:39,899 --> 03:39:40,899
as you may know computers talk in bits
5160
03:39:45,000 --> 03:39:46,000
ones and zeros ons and offs and this is
5161
03:39:48,540 --> 03:39:49,540
how all of the data that we deal with in
5162
03:39:51,120 --> 03:39:52,120
computers is transferred from one
5163
03:39:53,819 --> 03:39:54,819
computer to the next or one node to the
5164
03:39:56,580 --> 03:39:57,580
next over the media as we've discussed
5165
03:39:59,100 --> 03:40:00,100
but we want to talk exactly about how
5166
03:40:02,100 --> 03:40:03,100
these bits these ones and zeros get from
5167
03:40:05,040 --> 03:40:06,040
point A to point B and so in this uh
5168
03:40:09,600 --> 03:40:10,600
module we're going to talk about data
5169
03:40:12,060 --> 03:40:13,060
transmission
5170
03:40:13,200 --> 03:40:14,200
or how data makes it from one point to
5171
03:40:16,920 --> 03:40:17,920
the other
5172
03:40:18,180 --> 03:40:19,180
so we're going to start by talking about
5173
03:40:20,340 --> 03:40:21,340
data transmission methods and defining
5174
03:40:22,439 --> 03:40:23,439
exactly what data transmission is
5175
03:40:25,739 --> 03:40:26,739
we're also going to talk about
5176
03:40:27,500 --> 03:40:28,500
instantaneous data transfer and what
5177
03:40:31,020 --> 03:40:32,020
might require it the word instantaneous
5178
03:40:33,239 --> 03:40:34,239
meaning the data is sent instantaneously
5179
03:40:35,700 --> 03:40:36,700
the minute that it is created in some
5180
03:40:38,819 --> 03:40:39,819
instances data is first stored and then
5181
03:40:41,880 --> 03:40:42,880
converted and then transferred in this
5182
03:40:44,279 --> 03:40:45,279
case instantaneously the data is
5183
03:40:46,140 --> 03:40:47,140
transferred over the media we're also
5184
03:40:48,420 --> 03:40:49,420
going to discuss which we've seen in a
5185
03:40:50,700 --> 03:40:51,700
plus serial data transmission meaning
5186
03:40:53,580 --> 03:40:54,580
that one bit is sent at a time one after
5187
03:40:57,359 --> 03:40:58,359
the other and remember just as uh you
5188
03:41:00,479 --> 03:41:01,479
can recall one byte
5189
03:41:03,180 --> 03:41:04,180
equals
5190
03:41:04,620 --> 03:41:05,620
eight bits
5191
03:41:06,600 --> 03:41:07,600
byte being represented by that uppercase
5192
03:41:08,939 --> 03:41:09,939
b and a bit being represented by the
5193
03:41:12,779 --> 03:41:13,779
lowercase b
5194
03:41:14,760 --> 03:41:15,760
we're also going to talk about two
5195
03:41:16,739 --> 03:41:17,739
different communication methods in
5196
03:41:18,840 --> 03:41:19,840
serial data transmission asynchronous
5197
03:41:21,120 --> 03:41:22,120
and synchronous Communications with
5198
03:41:23,399 --> 03:41:24,399
which have to do with uh how the data is
5199
03:41:26,880 --> 03:41:27,880
synced up to a clock cycle with the CPU
5200
03:41:30,180 --> 03:41:31,180
and therefore how it's sent
5201
03:41:32,160 --> 03:41:33,160
then we're gonna have to find parallel
5202
03:41:34,439 --> 03:41:35,439
data transmission meaning that the data
5203
03:41:36,779 --> 03:41:37,779
instead of being sent one after the
5204
03:41:38,460 --> 03:41:39,460
other you may have eight bits of data
5205
03:41:40,800 --> 03:41:41,800
all sent at Once In Parallel with the
5206
03:41:43,560 --> 03:41:44,560
other
5207
03:41:44,340 --> 03:41:45,340
finally we're going to discuss baseband
5208
03:41:46,680 --> 03:41:47,680
transmission a digital transmission
5209
03:41:48,840 --> 03:41:49,840
method and Broadband transmission or
5210
03:41:52,080 --> 03:41:53,080
analog transmission method these are
5211
03:41:54,420 --> 03:41:55,420
specifically called out in the network
5212
03:41:56,279 --> 03:41:57,279
plus exam and so it's important that we
5213
03:41:58,620 --> 03:41:59,620
pay a special attention to those now
5214
03:42:01,620 --> 03:42:02,620
when we talk about data transmission
5215
03:42:03,899 --> 03:42:04,899
it's important that we have to
5216
03:42:05,640 --> 03:42:06,640
understand there are many ways that data
5217
03:42:08,220 --> 03:42:09,220
can be sent and received in essence data
5218
03:42:11,340 --> 03:42:12,340
transmission is the exchange of data
5219
03:42:14,340 --> 03:42:15,340
between devices on network by one method
5220
03:42:17,399 --> 03:42:18,399
or another the main thing that
5221
03:42:20,220 --> 03:42:21,220
differentiates data transmission from
5222
03:42:23,700 --> 03:42:24,700
say Voice or telephony transition is
5223
03:42:28,560 --> 03:42:29,560
that we're transmitting many different
5224
03:42:31,739 --> 03:42:32,739
things including text video and Graphics
5225
03:42:35,520 --> 03:42:36,520
all over the medium whereas telephony is
5226
03:42:38,640 --> 03:42:39,640
only dealing with voice this is
5227
03:42:40,979 --> 03:42:41,979
different from our telephones which are
5228
03:42:44,220 --> 03:42:45,220
are also transferring a sort of data but
5229
03:42:46,979 --> 03:42:47,979
that data doesn't include as many
5230
03:42:48,779 --> 03:42:49,779
different things
5231
03:42:50,760 --> 03:42:51,760
now when you might hear the term
5232
03:42:53,060 --> 03:42:54,060
computer network I just want to be clear
5233
03:42:56,100 --> 03:42:57,100
that computer network is the same as a
5234
03:42:58,979 --> 03:42:59,979
Data Network and so we might be using
5235
03:43:01,020 --> 03:43:02,020
those terms interchangeably but when
5236
03:43:02,939 --> 03:43:03,939
we're talking about data transmission
5237
03:43:04,340 --> 03:43:05,340
sometimes the term computer network as
5238
03:43:07,920 --> 03:43:08,920
opposed to Data Network comes up but
5239
03:43:09,600 --> 03:43:10,600
they are interchangeable
5240
03:43:11,279 --> 03:43:12,279
now in most cases when we're dealing
5241
03:43:14,760 --> 03:43:15,760
with networking the data is stored
5242
03:43:17,399 --> 03:43:18,399
somewhere at some point this also goes
5243
03:43:20,700 --> 03:43:21,700
for data that's ready to be transmitted
5244
03:43:22,859 --> 03:43:23,859
right we store it and then we send it
5245
03:43:25,620 --> 03:43:26,620
however there are some instances when
5246
03:43:27,840 --> 03:43:28,840
data needs to reach its destination as
5247
03:43:30,359 --> 03:43:31,359
soon as it's been generated or created
5248
03:43:32,279 --> 03:43:33,279
and we don't want to wait for it to be
5249
03:43:34,859 --> 03:43:35,859
written to memory or written to a hard
5250
03:43:36,779 --> 03:43:37,779
drive in these cases instantaneous
5251
03:43:40,920 --> 03:43:41,920
as the name implies being instant to the
5252
03:43:43,680 --> 03:43:44,680
moment data transfer occurs some
5253
03:43:46,920 --> 03:43:47,920
programs and applications such as online
5254
03:43:50,040 --> 03:43:51,040
chat uh video conferencing and voice
5255
03:43:53,100 --> 03:43:54,100
conferencing programs all via the
5256
03:43:55,080 --> 03:43:56,080
Internet require such a transfer the
5257
03:43:58,200 --> 03:43:59,200
this method of data transfer doesn't
5258
03:44:00,660 --> 03:44:01,660
store the data at any point before
5259
03:44:03,239 --> 03:44:04,239
transmitting it to memory
5260
03:44:05,580 --> 03:44:06,580
instead it immediately converts that
5261
03:44:08,520 --> 03:44:09,520
data into a network compatible format
5262
03:44:11,720 --> 03:44:12,720
and as it's being generated and then it
5263
03:44:14,819 --> 03:44:15,819
instantaneously transmits it now you can
5264
03:44:17,100 --> 03:44:18,100
understand why we would want to use that
5265
03:44:19,140 --> 03:44:20,140
in these specific instances I don't want
5266
03:44:21,359 --> 03:44:22,359
to store my chat stuff to memory and
5267
03:44:23,399 --> 03:44:24,399
then send it I want to chat and then
5268
03:44:25,319 --> 03:44:26,319
have it sent same with video
5269
03:44:26,700 --> 03:44:27,700
conferencing or voice conferencing I
5270
03:44:28,500 --> 03:44:29,500
don't want the lag that's going to occur
5271
03:44:30,060 --> 03:44:31,060
due to having to save it to memory and
5272
03:44:32,760 --> 03:44:33,760
then save it and then send it which is
5273
03:44:34,739 --> 03:44:35,739
why we want this instantaneous data
5274
03:44:37,080 --> 03:44:38,080
transfer
5275
03:44:39,000 --> 03:44:40,000
serial data transmission is a
5276
03:44:42,060 --> 03:44:43,060
transmission method that transmits bits
5277
03:44:45,420 --> 03:44:46,420
once per clock cycle now this clock
5278
03:44:48,660 --> 03:44:49,660
cycle refers to the CPU or central
5279
03:44:52,560 --> 03:44:53,560
processing unit of the computer and how
5280
03:44:55,200 --> 03:44:56,200
that's processing information and as you
5281
03:44:57,720 --> 03:44:58,720
can see from this illustration basically
5282
03:44:59,520 --> 03:45:00,520
what happens is we're sending one of
5283
03:45:01,859 --> 03:45:02,859
these bits
5284
03:45:03,540 --> 03:45:04,540
at a time
5285
03:45:05,220 --> 03:45:06,220
and if you recall
5286
03:45:07,380 --> 03:45:08,380
one byte equals eight serial bits and
5287
03:45:11,100 --> 03:45:12,100
that's what we're going to call eight
5288
03:45:12,180 --> 03:45:13,180
serial bits one byte now a couple
5289
03:45:14,460 --> 03:45:15,460
examples of what's uh of what uses
5290
03:45:17,460 --> 03:45:18,460
serial data transmission includes
5291
03:45:19,680 --> 03:45:20,680
ethernet as well as some peripheral
5292
03:45:22,680 --> 03:45:23,680
devices that connect to our computer
5293
03:45:24,120 --> 03:45:25,120
like mice and keyboards now with serial
5294
03:45:27,779 --> 03:45:28,779
data Transmissions there are different
5295
03:45:29,640 --> 03:45:30,640
methods that can be used to delineate
5296
03:45:32,939 --> 03:45:33,939
between the start bit and the stop bit
5297
03:45:36,060 --> 03:45:37,060
basically how they know
5298
03:45:38,700 --> 03:45:39,700
uh what where the data begins and ends
5299
03:45:42,540 --> 03:45:43,540
and also error checking or correcting
5300
03:45:44,760 --> 03:45:45,760
bits that allow the data to be uh fixed
5301
03:45:48,000 --> 03:45:49,000
in case it arrives incorrectly and the
5302
03:45:50,819 --> 03:45:51,819
data itself so let's take a look at the
5303
03:45:53,220 --> 03:45:54,220
difference between synchronous and the
5304
03:45:56,460 --> 03:45:57,460
asynchronous methods of data serial data
5305
03:45:59,040 --> 03:46:00,040
transmission
5306
03:46:00,420 --> 03:46:01,420
synchronous data transmission
5307
03:46:03,560 --> 03:46:04,560
utilizes standardized time intervals
5308
03:46:07,200 --> 03:46:08,200
when transmitting each bit now the
5309
03:46:09,960 --> 03:46:10,960
assumption that is made is that one byte
5310
03:46:12,720 --> 03:46:13,720
is sent every interval so the two
5311
03:46:15,359 --> 03:46:16,359
devices have to be in sync with each
5312
03:46:17,279 --> 03:46:18,279
other each other in regards to their
5313
03:46:19,140 --> 03:46:20,140
timing a clock chip therefore
5314
03:46:22,220 --> 03:46:23,220
not a great picture of it but imagine
5315
03:46:25,319 --> 03:46:26,319
that this is a chip is needed to ensure
5316
03:46:28,140 --> 03:46:29,140
that the devices are in sync with one
5317
03:46:30,000 --> 03:46:31,000
another now a special bit pattern is
5318
03:46:32,760 --> 03:46:33,760
inserted during a specified time
5319
03:46:35,220 --> 03:46:36,220
interval to maintain this
5320
03:46:37,380 --> 03:46:38,380
synchronization
5321
03:46:39,080 --> 03:46:40,080
asynchronous on the other hand uses
5322
03:46:42,000 --> 03:46:43,000
special start and stop patterns to
5323
03:46:45,300 --> 03:46:46,300
differentiate between the bytes in the
5324
03:46:47,399 --> 03:46:48,399
data Stream So the receiver just has to
5325
03:46:50,040 --> 03:46:51,040
look for these special patterns and then
5326
03:46:52,260 --> 03:46:53,260
can easily keep track of whether the
5327
03:46:54,120 --> 03:46:55,120
data has been successfully received so
5328
03:46:56,760 --> 03:46:57,760
for instance the pattern might be one
5329
03:46:58,620 --> 03:46:59,620
zero one zero and then uh or one zero
5330
03:47:02,520 --> 03:47:03,520
one zero one zero one zero and then the
5331
03:47:04,620 --> 03:47:05,620
device knows that that is the beginning
5332
03:47:06,960 --> 03:47:07,960
or the end of a pattern of bytes of data
5333
03:47:11,279 --> 03:47:12,279
the benefit of course is we don't need
5334
03:47:13,380 --> 03:47:14,380
this chip because the start and stop
5335
03:47:16,260 --> 03:47:17,260
times are built automatically into the
5336
03:47:18,720 --> 03:47:19,720
data itself
5337
03:47:20,279 --> 03:47:21,279
now stepping away from serial data
5338
03:47:22,380 --> 03:47:23,380
transmission
5339
03:47:23,300 --> 03:47:24,300
parallel data transmission is a transmit
5340
03:47:26,700 --> 03:47:27,700
Mission method that uses multiple
5341
03:47:29,700 --> 03:47:30,700
transmission lines wires or cables
5342
03:47:33,180 --> 03:47:34,180
simultaneously unlike serial
5343
03:47:35,520 --> 03:47:36,520
transmission that sends start and stop
5344
03:47:37,800 --> 03:47:38,800
and synchronization bits along with the
5345
03:47:40,680 --> 03:47:41,680
data parallel does not and doesn't have
5346
03:47:43,080 --> 03:47:44,080
to those bits are sent separately via
5347
03:47:46,680 --> 03:47:47,680
one of these multiple other different
5348
03:47:49,859 --> 03:47:50,859
transmission lines other than the data
5349
03:47:52,439 --> 03:47:53,439
because of this throughput is generally
5350
03:47:55,140 --> 03:47:56,140
better than standard serial transmission
5351
03:47:57,920 --> 03:47:58,920
and these eight of these parallel bits
5352
03:48:02,160 --> 03:48:03,160
are referred to as a character as
5353
03:48:04,800 --> 03:48:05,800
opposed to a byte now some examples that
5354
03:48:07,859 --> 03:48:08,859
use parallel transmission are scuzzy
5355
03:48:11,060 --> 03:48:12,060
parallel ports PC card or
5356
03:48:15,200 --> 03:48:16,200
pcmcia remember piece parallel ports
5357
03:48:18,540 --> 03:48:19,540
those are those printer ports
5358
03:48:20,880 --> 03:48:21,880
and may all use parallel data
5359
03:48:23,100 --> 03:48:24,100
transmission it's not as used or widely
5360
03:48:26,340 --> 03:48:27,340
used as a serial data transmission is
5361
03:48:29,460 --> 03:48:30,460
now that deals with how the data is sent
5362
03:48:32,160 --> 03:48:33,160
let's deal with the type of signal
5363
03:48:35,399 --> 03:48:36,399
that's sent
5364
03:48:36,899 --> 03:48:37,899
in baseband's transmission this utilizes
5365
03:48:40,260 --> 03:48:41,260
digital signals sent via a direct
5366
03:48:43,319 --> 03:48:44,319
current pulse and remember we're talking
5367
03:48:45,239 --> 03:48:46,239
about direct current versus alternating
5368
03:48:47,220 --> 03:48:48,220
current with base bands all the devices
5369
03:48:50,040 --> 03:48:51,040
share the same medium or Channel and
5370
03:48:53,580 --> 03:48:54,580
can't transmit and receive
5371
03:48:55,340 --> 03:48:56,340
simultaneously however multiple baseband
5372
03:48:59,279 --> 03:49:00,279
channels can be combined over one medium
5373
03:49:02,640 --> 03:49:03,640
to use a channel separated with specific
5374
03:49:06,540 --> 03:49:07,540
time slots and that's how we can
5375
03:49:08,880 --> 03:49:09,880
determine when it's being sent and when
5376
03:49:10,979 --> 03:49:11,979
it's being received one thing to notice
5377
03:49:12,960 --> 03:49:13,960
in a digital signal as well is that
5378
03:49:15,540 --> 03:49:16,540
we're only dealing with ones or zeros on
5379
03:49:18,540 --> 03:49:19,540
and off and so the signal is either on
5380
03:49:23,640 --> 03:49:24,640
or off there's no sort of wave that
5381
03:49:27,359 --> 03:49:28,359
we're gonna get with the analog signal
5382
03:49:29,100 --> 03:49:30,100
which we'll see right now
5383
03:49:32,100 --> 03:49:33,100
so where baseband used those digital
5384
03:49:35,040 --> 03:49:36,040
signals to transmit data broadband's
5385
03:49:37,439 --> 03:49:38,439
going to use analog signals and you can
5386
03:49:39,540 --> 03:49:40,540
see that represented in this wave also
5387
03:49:42,540 --> 03:49:43,540
unlike baseband Broadband utilizes the
5388
03:49:45,720 --> 03:49:46,720
entire bandwidth available and it's only
5389
03:49:48,540 --> 03:49:49,540
going to travel in one direction or
5390
03:49:51,000 --> 03:49:52,000
unidirectionally because devices can't
5391
03:49:53,460 --> 03:49:54,460
send and receive over the same channel
5392
03:49:55,319 --> 03:49:56,319
now if more throughput is needed that's
5393
03:49:58,800 --> 03:49:59,800
fine we can combine and send across
5394
03:50:01,979 --> 03:50:02,979
multiple frequencies channels or we can
5395
03:50:05,160 --> 03:50:06,160
use over just one medium
5396
03:50:07,380 --> 03:50:08,380
generally speaking we're going to see a
5397
03:50:09,840 --> 03:50:10,840
lot of broadband in the field because a
5398
03:50:13,260 --> 03:50:14,260
lot of our current infrastructure was
5399
03:50:15,840 --> 03:50:16,840
created for analog signals as opposed to
5400
03:50:19,380 --> 03:50:20,380
digital or baseband signals now
5401
03:50:22,920 --> 03:50:23,920
Broadband over power lines or BPL is an
5402
03:50:27,899 --> 03:50:28,899
emerging technology that still mostly in
5403
03:50:31,200 --> 03:50:32,200
the testing phases in the US the premise
5404
03:50:34,439 --> 03:50:35,439
of it is that we can essentially bring
5405
03:50:37,380 --> 03:50:38,380
high-speed internet
5406
03:50:39,439 --> 03:50:40,439
two power outlets using the power lines
5407
03:50:43,560 --> 03:50:44,560
and the infrastructure that's already
5408
03:50:45,060 --> 03:50:46,060
been built once this technology is fully
5409
03:50:47,939 --> 03:50:48,939
developed you would be able to plug your
5410
03:50:50,399 --> 03:50:51,399
computer into a power outlet in your
5411
03:50:52,140 --> 03:50:53,140
home and you can get decently fast
5412
03:50:54,540 --> 03:50:55,540
internet between 500 kilobits per second
5413
03:50:57,060 --> 03:50:58,060
and three megabits per second which are
5414
03:50:59,460 --> 03:51:00,460
about equivalent to DSL or cable speeds
5415
03:51:02,760 --> 03:51:03,760
now of course the main concern with this
5416
03:51:05,160 --> 03:51:06,160
type of transmission is a the effect
5417
03:51:07,739 --> 03:51:08,739
that the uh since we're dealing with
5418
03:51:09,840 --> 03:51:10,840
electrical interest infrastructure the
5419
03:51:11,819 --> 03:51:12,819
effect that the electricity is going to
5420
03:51:13,560 --> 03:51:14,560
cause uh on
5421
03:51:16,020 --> 03:51:17,020
uh the data being sent remember we were
5422
03:51:19,260 --> 03:51:20,260
talking about Emi and crosstalk and the
5423
03:51:21,720 --> 03:51:22,720
noise issue previously and also security
5424
03:51:25,319 --> 03:51:26,319
since if we're using something that
5425
03:51:27,359 --> 03:51:28,359
everyone has access to we're also going
5426
03:51:29,460 --> 03:51:30,460
to be opening our data up to some issues
5427
03:51:32,640 --> 03:51:33,640
so for these reasons we might not ever
5428
03:51:35,160 --> 03:51:36,160
see BPL or Broadband over power lines
5429
03:51:37,859 --> 03:51:38,859
really come to full fruition especially
5430
03:51:40,380 --> 03:51:41,380
with the prevalence of Wi-Fi
5431
03:51:42,660 --> 03:51:43,660
technologies that are now becoming uh
5432
03:51:46,200 --> 03:51:47,200
installed all over the place and might
5433
03:51:48,300 --> 03:51:49,300
make BPL extinct before it even has a
5434
03:51:51,479 --> 03:51:52,479
chance to flourish
5435
03:51:53,880 --> 03:51:54,880
so just to cover what we've talked about
5436
03:51:55,979 --> 03:51:56,979
we talked about data transmission uh
5437
03:51:59,340 --> 03:52:00,340
meaning that we're transferring data
5438
03:52:01,859 --> 03:52:02,859
over a computer or a Data Network we
5439
03:52:04,739 --> 03:52:05,739
looked at instantaneous data transfer
5440
03:52:07,319 --> 03:52:08,319
which means that the data is not stored
5441
03:52:10,800 --> 03:52:11,800
to memory
5442
03:52:16,800 --> 03:52:17,800
we also talked about serial data
5443
03:52:19,140 --> 03:52:20,140
transmission in which one bit is sent at
5444
03:52:23,160 --> 03:52:24,160
a time
5445
03:52:25,020 --> 03:52:26,020
and remember we have eight bits
5446
03:52:28,680 --> 03:52:29,680
in a byte
5447
03:52:31,680 --> 03:52:32,680
we looked at asynchronous versus
5448
03:52:34,380 --> 03:52:35,380
synchronous communication synchronous
5449
03:52:36,979 --> 03:52:37,979
requires some sort of clock chip whereas
5450
03:52:40,200 --> 03:52:41,200
asynchronous embeds
5451
03:52:44,040 --> 03:52:45,040
start and stop
5452
03:52:47,700 --> 03:52:48,700
into the transfer
5453
03:52:54,479 --> 03:52:55,479
we also looked at parallel data
5454
03:52:56,640 --> 03:52:57,640
transmission having bits sent all
5455
03:53:00,420 --> 03:53:01,420
concurrently at the same time not as not
5456
03:53:04,620 --> 03:53:05,620
as widely used and remember although I
5457
03:53:07,260 --> 03:53:08,260
don't think you'll see this
5458
03:53:09,120 --> 03:53:10,120
on the exam eight parallel bits
5459
03:53:13,560 --> 03:53:14,560
equal one what we call a character
5460
03:53:17,819 --> 03:53:18,819
we also looked at baseband transmission
5461
03:53:20,100 --> 03:53:21,100
the important thing to remember there is
5462
03:53:22,380 --> 03:53:23,380
that it is digital and Broadband
5463
03:53:24,660 --> 03:53:25,660
transmission which is analog
5464
03:53:28,380 --> 03:53:29,380
finally we talked about BPL or broadband
5465
03:53:33,899 --> 03:53:34,899
over power lines which is a technology
5466
03:53:36,720 --> 03:53:37,720
that would bring Broadband speeds over
5467
03:53:39,540 --> 03:53:40,540
the power lines that are already in
5468
03:53:41,460 --> 03:53:42,460
place
5469
03:53:45,890 --> 03:53:46,890
[Music]
5470
03:53:54,500 --> 03:53:55,500
thank you
5471
03:54:05,840 --> 03:54:06,840
network communications media access
5472
03:54:09,359 --> 03:54:10,359
methods
5473
03:54:11,640 --> 03:54:12,640
so we've discussed and explained the
5474
03:54:14,580 --> 03:54:15,580
different media and the different
5475
03:54:16,020 --> 03:54:17,020
devices that exist on different types of
5476
03:54:18,720 --> 03:54:19,720
networks and we even just talked about
5477
03:54:21,239 --> 03:54:22,239
how that data is transferred from point
5478
03:54:23,520 --> 03:54:24,520
A to point B but we have a lot of
5479
03:54:25,739 --> 03:54:26,739
different devices of buying for access
5480
03:54:27,960 --> 03:54:28,960
to this media in order to send its data
5481
03:54:30,300 --> 03:54:31,300
and so we need to create certain rules
5482
03:54:32,580 --> 03:54:33,580
that provide access to the media and so
5483
03:54:35,520 --> 03:54:36,520
what we're going to talk about in this
5484
03:54:37,080 --> 03:54:38,080
module is first what media access is and
5485
03:54:41,460 --> 03:54:42,460
why we need it and why we need to
5486
03:54:42,960 --> 03:54:43,960
understand it for the network plus exam
5487
03:54:45,239 --> 03:54:46,239
and as administrators we're also going
5488
03:54:47,760 --> 03:54:48,760
to describe two different barrage
5489
03:54:51,359 --> 03:54:52,359
areas of media access including
5490
03:54:54,060 --> 03:54:55,060
contention based media access versus
5491
03:54:57,859 --> 03:54:58,859
controlled media access one in which we
5492
03:55:01,140 --> 03:55:02,140
sort of fight for access to the media uh
5493
03:55:03,960 --> 03:55:04,960
contend for it if you will and the other
5494
03:55:05,939 --> 03:55:06,939
in which it is controlled generally by
5495
03:55:08,220 --> 03:55:09,220
some sort of central device
5496
03:55:10,920 --> 03:55:11,920
and then we're going to Define uh
5497
03:55:13,439 --> 03:55:14,439
multiplexing which allows us to send
5498
03:55:15,720 --> 03:55:16,720
multiple signals over a single medium
5499
03:55:18,000 --> 03:55:19,000
and we're going to talk about two
5500
03:55:19,979 --> 03:55:20,979
different types of multiplexing time
5501
03:55:22,739 --> 03:55:23,739
division multiplexing
5502
03:55:25,819 --> 03:55:26,819
and frequency division multiplexing
5503
03:55:33,000 --> 03:55:34,000
and we'll discuss how those work and why
5504
03:55:35,760 --> 03:55:36,760
we need two different ones
5505
03:55:37,680 --> 03:55:38,680
then we're going to discuss polling
5506
03:55:40,140 --> 03:55:41,140
which is how we check to see which
5507
03:55:43,020 --> 03:55:44,020
devices need to send
5508
03:55:45,120 --> 03:55:46,120
um
5509
03:55:46,800 --> 03:55:47,800
data
5510
03:55:48,660 --> 03:55:49,660
and we're going to differentiate between
5511
03:55:51,319 --> 03:55:52,319
csma CD and CA now csma you don't really
5512
03:55:56,340 --> 03:55:57,340
need to worry about that but it does
5513
03:55:58,080 --> 03:55:59,080
stand for carrier
5514
03:56:00,660 --> 03:56:01,660
sense
5515
03:56:02,760 --> 03:56:03,760
multiple access
5516
03:56:07,080 --> 03:56:08,080
but the real important thing here is to
5517
03:56:09,060 --> 03:56:10,060
know the difference between Collision
5518
03:56:10,680 --> 03:56:11,680
detection
5519
03:56:14,899 --> 03:56:15,899
and collision avoidance and these are
5520
03:56:18,960 --> 03:56:19,960
the two main methods we're going to see
5521
03:56:20,899 --> 03:56:21,899
uh for ethernet
5522
03:56:25,979 --> 03:56:26,979
and then for wireless and we'll explain
5523
03:56:28,739 --> 03:56:29,739
why that is later on
5524
03:56:33,020 --> 03:56:34,020
finally we need to differentiate between
5525
03:56:35,580 --> 03:56:36,580
a contention contention domain and a
5526
03:56:38,939 --> 03:56:39,939
broadcast domain basically uh how large
5527
03:56:41,939 --> 03:56:42,939
or how many other devices they need to
5528
03:56:45,020 --> 03:56:46,020
contend against or that can get
5529
03:56:47,699 --> 03:56:48,699
broadcast a certain message and these
5530
03:56:50,100 --> 03:56:51,100
are also divided by those two different
5531
03:56:51,960 --> 03:56:52,960
devices that keep coming up switches and
5532
03:56:55,199 --> 03:56:56,199
routers
5533
03:56:56,760 --> 03:56:57,760
so if that seems confusing enough to you
5534
03:56:58,859 --> 03:56:59,859
let's delve in in order to shed some
5535
03:57:00,960 --> 03:57:01,960
light on what all of this is now as
5536
03:57:03,960 --> 03:57:04,960
administrators it's really important
5537
03:57:05,580 --> 03:57:06,580
that we understand the rules that are in
5538
03:57:08,279 --> 03:57:09,279
place for different types of networks
5539
03:57:10,800 --> 03:57:11,800
for instance if I were in a crowded room
5540
03:57:13,680 --> 03:57:14,680
and I had a secret message that I needed
5541
03:57:16,859 --> 03:57:17,859
to get across to someone in the corner
5542
03:57:19,020 --> 03:57:20,020
of the room and I were just to shout out
5543
03:57:21,060 --> 03:57:22,060
that message there's no rules in the
5544
03:57:23,520 --> 03:57:24,520
world that say everyone else has to
5545
03:57:25,560 --> 03:57:26,560
ignore what I'm saying and they could
5546
03:57:27,660 --> 03:57:28,660
just listen or or there's nothing that
5547
03:57:30,120 --> 03:57:31,120
says that everyone else couldn't talk at
5548
03:57:31,920 --> 03:57:32,920
the same time meaning that then my
5549
03:57:34,020 --> 03:57:35,020
message wouldn't make it now that's
5550
03:57:36,479 --> 03:57:37,479
means there's no rules for communication
5551
03:57:39,420 --> 03:57:40,420
in real life but in networks and
5552
03:57:42,300 --> 03:57:43,300
computer networks and data networks
5553
03:57:43,920 --> 03:57:44,920
there are many different types of rules
5554
03:57:45,779 --> 03:57:46,779
and here we're going to talk about some
5555
03:57:48,180 --> 03:57:49,180
of the media access rules or the rules
5556
03:57:50,640 --> 03:57:51,640
that govern which node or which device
5557
03:57:53,699 --> 03:57:54,699
has access and the ability to transmit
5558
03:57:56,760 --> 03:57:57,760
on the media at any one time and when
5559
03:57:59,760 --> 03:58:00,760
they're allowed to send and receive and
5560
03:58:03,359 --> 03:58:04,359
for how long now these rules are crucial
5561
03:58:06,600 --> 03:58:07,600
they ensure that data delivery and
5562
03:58:09,420 --> 03:58:10,420
integrity and by the way when we say
5563
03:58:11,760 --> 03:58:12,760
Integrity we mean that the data we
5564
03:58:13,620 --> 03:58:14,620
intended to send is actually what was
5565
03:58:15,899 --> 03:58:16,899
sent it hasn't been tampered with uh are
5566
03:58:18,899 --> 03:58:19,899
maintained now there are two general
5567
03:58:21,420 --> 03:58:22,420
categories for types of media access
5568
03:58:23,840 --> 03:58:24,840
these are contention based and
5569
03:58:27,180 --> 03:58:28,180
controlled media access so let's take a
5570
03:58:29,699 --> 03:58:30,699
look at the differences between those
5571
03:58:31,260 --> 03:58:32,260
now and they'll come back when we talk
5572
03:58:33,359 --> 03:58:34,359
later about csma CD and CA not to
5573
03:58:37,080 --> 03:58:38,080
mention contention broadcast domains
5574
03:58:39,180 --> 03:58:40,180
with contention-based media access nodes
5575
03:58:42,960 --> 03:58:43,960
on the network are competing with one
5576
03:58:46,140 --> 03:58:47,140
another for media access time and
5577
03:58:49,439 --> 03:58:50,439
utilization another term for this kind
5578
03:58:52,260 --> 03:58:53,260
of media is competitive or Collision
5579
03:58:54,899 --> 03:58:55,899
based and yes that means that they're
5580
03:58:57,359 --> 03:58:58,359
actually the data packets are colliding
5581
03:58:59,580 --> 03:59:00,580
and that's how we determine which can go
5582
03:59:03,000 --> 03:59:04,000
right which is allowed to be sent now
5583
03:59:05,580 --> 03:59:06,580
these are pretty easy to implement
5584
03:59:07,080 --> 03:59:08,080
however data can be delayed for nodes
5585
03:59:10,140 --> 03:59:11,140
that need immediate access to the
5586
03:59:12,060 --> 03:59:13,060
network media because collisions are
5587
03:59:14,880 --> 03:59:15,880
going to occur as the name implies and
5588
03:59:17,279 --> 03:59:18,279
that's going to delay Network traffic
5589
03:59:19,080 --> 03:59:20,080
now as a opposed to contention-based
5590
03:59:21,720 --> 03:59:22,720
Media access we also have controlled
5591
03:59:24,479 --> 03:59:25,479
media access so instead of me fighting
5592
03:59:27,840 --> 03:59:28,840
for access to the media I'm granted
5593
03:59:30,420 --> 03:59:31,420
access to the media and the way this
5594
03:59:32,160 --> 03:59:33,160
works is we use a central device that's
5595
03:59:35,819 --> 03:59:36,819
put in place to ensure that access to
5596
03:59:39,120 --> 03:59:40,120
the media is guaranteed for devices that
5597
03:59:41,399 --> 03:59:42,399
have certain time sensitive data and
5598
03:59:43,979 --> 03:59:44,979
they can transmit it when necessary
5599
03:59:45,859 --> 03:59:46,859
because of the because of this and these
5600
03:59:48,540 --> 03:59:49,540
devices that need to be added these are
5601
03:59:50,340 --> 03:59:51,340
much more difficult to implement and
5602
03:59:52,439 --> 03:59:53,439
maintain but they're highly reliable as
5603
03:59:55,319 --> 03:59:56,319
you can imagine and also make sure that
5604
03:59:57,239 --> 03:59:58,239
no device has more access than another
5605
03:59:58,859 --> 03:59:59,859
when it comes to access time so take for
5606
04:00:02,220 --> 04:00:03,220
instance a device that has a safety
5607
04:00:04,739 --> 04:00:05,739
function that when an emergency event
5608
04:00:06,899 --> 04:00:07,899
occurs right it has to have immediate
5609
04:00:09,300 --> 04:00:10,300
access to the network and to the network
5610
04:00:11,100 --> 04:00:12,100
resources so it can send instructions to
5611
04:00:14,340 --> 04:00:15,340
say heavy machinery that needs to shut
5612
04:00:16,739 --> 04:00:17,739
down in case an emergency in that case
5613
04:00:18,960 --> 04:00:19,960
we don't want it to be intending for
5614
04:00:20,699 --> 04:00:21,699
Access we want it to be granted
5615
04:00:22,319 --> 04:00:23,319
immediate access and so this is where
5616
04:00:24,420 --> 04:00:25,420
controlled media access can really come
5617
04:00:26,220 --> 04:00:27,220
in handy
5618
04:00:27,300 --> 04:00:28,300
so while we're talking about controlled
5619
04:00:29,640 --> 04:00:30,640
media access and we've just talked about
5620
04:00:32,239 --> 04:00:33,239
controlled and contention based media
5621
04:00:36,300 --> 04:00:37,300
access let's keep talking about control
5622
04:00:38,160 --> 04:00:39,160
based media access more specifically
5623
04:00:40,100 --> 04:00:41,100
discussing a few different controlled
5624
04:00:43,080 --> 04:00:44,080
based uh or controlled media access
5625
04:00:45,960 --> 04:00:46,960
methods the first I want to talk about
5626
04:00:48,000 --> 04:00:49,000
is called multiplexing and multiplexing
5627
04:00:51,000 --> 04:00:52,000
is a controlled media access method I'm
5628
04:00:54,239 --> 04:00:55,239
just going to add control there so that
5629
04:00:56,040 --> 04:00:57,040
we remember that this is related to
5630
04:00:59,720 --> 04:01:00,720
controlled not contention based it takes
5631
04:01:04,199 --> 04:01:05,199
multiple signals and combines them over
5632
04:01:07,319 --> 04:01:08,319
one single Network medium now data can
5633
04:01:10,680 --> 04:01:11,680
actually be multiplexed using two
5634
04:01:13,080 --> 04:01:14,080
different methods time Division
5635
04:01:15,239 --> 04:01:16,239
multiplexing and frequency division
5636
04:01:18,000 --> 04:01:19,000
multiplexing so let's first look at time
5637
04:01:21,239 --> 04:01:22,239
division multiplexing this is where
5638
04:01:23,939 --> 04:01:24,939
channels are divided into time slots and
5639
04:01:27,660 --> 04:01:28,660
each node on the network is assigned a
5640
04:01:30,180 --> 04:01:31,180
specific time slot
5641
04:01:33,899 --> 04:01:34,899
during that time slot the node has
5642
04:01:36,420 --> 04:01:37,420
dedicated sole access to the network
5643
04:01:39,660 --> 04:01:40,660
until that time has ended and then the
5644
04:01:42,060 --> 04:01:43,060
next node is allowed to transmit now
5645
04:01:44,760 --> 04:01:45,760
there's a device that we're going to
5646
04:01:46,020 --> 04:01:47,020
talk about in just a minute called the
5647
04:01:47,340 --> 04:01:48,340
Mox and this MOX takes the signals from
5648
04:01:50,220 --> 04:01:51,220
each of the nodes and sends it across
5649
04:01:52,439 --> 04:01:53,439
the network
5650
04:01:53,399 --> 04:01:54,399
now with TDM multiple
5651
04:01:56,100 --> 04:01:57,100
base band signals and remember baseband
5652
04:01:59,580 --> 04:02:00,580
is
5653
04:02:01,199 --> 04:02:02,199
digital
5654
04:02:03,239 --> 04:02:04,239
again represented here by that Digital
5655
04:02:06,560 --> 04:02:07,560
Signal because there is no curve in the
5656
04:02:10,080 --> 04:02:11,080
wave which would be analog and we'll see
5657
04:02:12,239 --> 04:02:13,239
that in just a second
5658
04:02:13,500 --> 04:02:14,500
it allows these digital signals these
5659
04:02:16,080 --> 04:02:17,080
baseband channels to be combined and
5660
04:02:18,060 --> 04:02:19,060
sent over one network medium
5661
04:02:20,760 --> 04:02:21,760
on the other hand we also have something
5662
04:02:22,500 --> 04:02:23,500
called frequency division multiplexing
5663
04:02:25,080 --> 04:02:26,080
this is where data from multiple nodes
5664
04:02:27,600 --> 04:02:28,600
is sent over many different frequencies
5665
04:02:30,239 --> 04:02:31,239
as opposed to given a specific time each
5666
04:02:33,420 --> 04:02:34,420
node has complete access to its
5667
04:02:35,520 --> 04:02:36,520
frequency and dedicated communication
5668
04:02:38,460 --> 04:02:39,460
with the MOX that device that is
5669
04:02:41,220 --> 04:02:42,220
basically controlling all of this
5670
04:02:43,260 --> 04:02:44,260
the mux combines the received signals
5671
04:02:46,439 --> 04:02:47,439
from the nodes and then transmitted
5672
04:02:48,180 --> 04:02:49,180
across the medium the important thing
5673
04:02:49,920 --> 04:02:50,920
you're here to know is that this we're
5674
04:02:51,960 --> 04:02:52,960
dealing with Broadband or analog signals
5675
04:02:56,340 --> 04:02:57,340
now we've been talking about
5676
04:02:59,640 --> 04:03:00,640
uh the mux so let's just talk about that
5677
04:03:02,220 --> 04:03:03,220
really briefly the MOX is the central
5678
04:03:05,640 --> 04:03:06,640
device that or which is also called a
5679
04:03:09,180 --> 04:03:10,180
multiplexer
5680
04:03:10,680 --> 04:03:11,680
that combines the signals and transmits
5681
04:03:13,080 --> 04:03:14,080
them to the receiving end or a demux or
5682
04:03:15,359 --> 04:03:16,359
a d multiplexer separates the signals
5683
04:03:17,760 --> 04:03:18,760
out again now remember this is all
5684
04:03:20,000 --> 04:03:21,000
controlled access and this mux is that
5685
04:03:23,580 --> 04:03:24,580
device we were talking about that is
5686
04:03:25,920 --> 04:03:26,920
doing the controlling now a different
5687
04:03:28,620 --> 04:03:29,620
type of controlled media access method
5688
04:03:31,319 --> 04:03:32,319
is called polling and as the name
5689
04:03:33,600 --> 04:03:34,600
implies we have a central device as well
5690
04:03:35,939 --> 04:03:36,939
that goes to each node in the network in
5691
04:03:38,279 --> 04:03:39,279
turn and C's and queries them do you
5692
04:03:41,100 --> 04:03:42,100
have any data to transmit with polling
5693
04:03:43,739 --> 04:03:44,739
then there is guaranteed access because
5694
04:03:46,140 --> 04:03:47,140
the process is constantly repeating
5695
04:03:48,180 --> 04:03:49,180
basically it's just constantly if we
5696
04:03:50,220 --> 04:03:51,220
have this middle mux sort of device it's
5697
04:03:52,859 --> 04:03:53,859
constantly going
5698
04:03:54,479 --> 04:03:55,479
to each
5699
04:03:59,939 --> 04:04:00,939
device and saying hey are you ready to
5700
04:04:02,340 --> 04:04:03,340
send something you now have access
5701
04:04:03,979 --> 04:04:04,979
although this guaranteed access in this
5702
04:04:06,779 --> 04:04:07,779
method is reliable it might not be as
5703
04:04:09,540 --> 04:04:10,540
effective in time sensitive Networks
5704
04:04:13,800 --> 04:04:14,800
and time can affect sometimes
5705
04:04:15,899 --> 04:04:16,899
potentially be wasted
5706
04:04:18,300 --> 04:04:19,300
in this querying in this polling because
5707
04:04:21,380 --> 04:04:22,380
sometimes I'm having to ask devices that
5708
04:04:23,819 --> 04:04:24,819
don't need to transmit anything to if
5709
04:04:25,920 --> 04:04:26,920
they need to transmit so this basically
5710
04:04:27,960 --> 04:04:28,960
wastes time another example of this by
5711
04:04:31,199 --> 04:04:32,199
the way is if for instance node a at one
5712
04:04:34,319 --> 04:04:35,319
point
5713
04:04:35,760 --> 04:04:36,760
finds it as data to transmit node a has
5714
04:04:39,420 --> 04:04:40,420
to wait until basically the polling
5715
04:04:41,580 --> 04:04:42,580
device comes all the way around to it
5716
04:04:43,979 --> 04:04:44,979
before it's allowed to transmit the data
5717
04:04:46,380 --> 04:04:47,380
now this can take a lot longer than
5718
04:04:48,300 --> 04:04:49,300
simply just asking if it can then just
5719
04:04:51,300 --> 04:04:52,300
send the data along
5720
04:04:53,399 --> 04:04:54,399
now because of these negatives there's a
5721
04:04:55,620 --> 04:04:56,620
variation of this polling which is
5722
04:04:57,779 --> 04:04:58,779
called demand priority where each node
5723
04:05:01,979 --> 04:05:02,979
signals when it has to transmit or not
5724
04:05:05,160 --> 04:05:06,160
transmit this method contains within it
5725
04:05:07,920 --> 04:05:08,920
measures to Grant priority to nodes that
5726
04:05:10,800 --> 04:05:11,800
have immediate data that it needs to
5727
04:05:12,840 --> 04:05:13,840
transmit it also contains measures and
5728
04:05:15,540 --> 04:05:16,540
controls to ensure that nodes can't
5729
04:05:18,060 --> 04:05:19,060
constantly signal they have priority
5730
04:05:20,220 --> 04:05:21,220
data because then you would have one
5731
04:05:22,920 --> 04:05:23,920
device that's constantly sort of hogging
5732
04:05:25,199 --> 04:05:26,199
your network so those are our controlled
5733
04:05:27,779 --> 04:05:28,779
based media access let's and and really
5734
04:05:30,840 --> 04:05:31,840
we we see these employed in certain
5735
04:05:32,939 --> 04:05:33,939
circumstances but you're going to more
5736
04:05:35,279 --> 04:05:36,279
encounter
5737
04:05:36,920 --> 04:05:37,920
contention-based media access and in
5738
04:05:39,359 --> 04:05:40,359
contention-based media access there are
5739
04:05:40,979 --> 04:05:41,979
two different types I want to talk about
5740
04:05:42,180 --> 04:05:43,180
Collision detection is a
5741
04:05:44,899 --> 04:05:45,899
contention-based media access method
5742
04:05:47,640 --> 04:05:48,640
that attempts to provide Collision free
5743
04:05:51,680 --> 04:05:52,680
data transfer in Ethernet local area
5744
04:05:54,720 --> 04:05:55,720
Networks so the key here is this is what
5745
04:05:57,720 --> 04:05:58,720
ethernet uses with csma CD or Collision
5746
04:06:01,500 --> 04:06:02,500
detection nodes transmit when they have
5747
04:06:04,199 --> 04:06:05,199
data to send and then when a collision
5748
04:06:06,720 --> 04:06:07,720
occurs they're basically detected
5749
04:06:09,439 --> 04:06:10,439
managed and then the data is resent or
5750
04:06:12,840 --> 04:06:13,840
retransmitted appropriately to get a
5751
04:06:15,000 --> 04:06:16,000
better sense of this and because it's
5752
04:06:16,380 --> 04:06:17,380
one that we really need to understand
5753
04:06:17,880 --> 04:06:18,880
let's take a look
5754
04:06:19,920 --> 04:06:20,920
at um an image to give us an idea
5755
04:06:24,779 --> 04:06:25,779
so there are five steps in Collision in
5756
04:06:28,380 --> 04:06:29,380
this Collision detection which again I'm
5757
04:06:30,060 --> 04:06:31,060
just going to throw this up there is a
5758
04:06:32,160 --> 04:06:33,160
contention
5759
04:06:33,199 --> 04:06:34,199
based media access method
5760
04:06:36,359 --> 04:06:37,359
in step one we just say that the node
5761
04:06:39,600 --> 04:06:40,600
itself wants to uh transmit data so what
5762
04:06:43,439 --> 04:06:44,439
it then does in step two is it basically
5763
04:06:45,420 --> 04:06:46,420
checks the network for availability
5764
04:06:48,120 --> 04:06:49,120
now in step three the node transmits
5765
04:06:50,640 --> 04:06:51,640
that data and waits for an
5766
04:06:52,319 --> 04:06:53,319
acknowledgment from the receiver that it
5767
04:06:54,479 --> 04:06:55,479
got there which is called an ack
5768
04:06:57,779 --> 04:06:58,779
packet an acknowledgment packet in step
5769
04:07:01,560 --> 04:07:02,560
four this is where stuff really happens
5770
04:07:03,140 --> 04:07:04,140
uh if there is a collision the packet
5771
04:07:06,960 --> 04:07:07,960
size will identify if one occurred
5772
04:07:09,120 --> 04:07:10,120
because what happens is boom I have this
5773
04:07:11,399 --> 04:07:12,399
collision and now my packet size changes
5774
04:07:13,739 --> 04:07:14,739
so in step five if that Collision
5775
04:07:16,140 --> 04:07:17,140
occurred both transmitting nodes and by
5776
04:07:18,600 --> 04:07:19,600
the way the reason a a collision is
5777
04:07:20,760 --> 04:07:21,760
going to occur is because another device
5778
04:07:22,260 --> 04:07:23,260
is also trying to transmit at the same
5779
04:07:25,500 --> 04:07:26,500
time so in step five if the Collision
5780
04:07:28,020 --> 04:07:29,020
occurred I wait a set period of time and
5781
04:07:30,960 --> 04:07:31,960
then I try to retransmit again now this
5782
04:07:33,899 --> 04:07:34,899
might seem like it's not a very
5783
04:07:35,220 --> 04:07:36,220
effective way of transmitting data but
5784
04:07:37,680 --> 04:07:38,680
it happens at such a fast speed that
5785
04:07:39,660 --> 04:07:40,660
actually it works quite well as long as
5786
04:07:42,239 --> 04:07:43,239
we don't have too many devices in the
5787
04:07:44,399 --> 04:07:45,399
same network contending for Access which
5788
04:07:47,100 --> 04:07:48,100
we'll talk about in just a bit now you
5789
04:07:49,199 --> 04:07:50,199
can understand why this works really
5790
04:07:50,580 --> 04:07:51,580
well in Ethernet networks wired Networks
5791
04:07:54,779 --> 04:07:55,779
because I can continue to collide and
5792
04:07:58,140 --> 04:07:59,140
then send something out again and many
5793
04:07:59,819 --> 04:08:00,819
times as I need until the data gets
5794
04:08:01,439 --> 04:08:02,439
there but in wireless settings this
5795
04:08:04,439 --> 04:08:05,439
isn't really going to work so well for
5796
04:08:05,880 --> 04:08:06,880
us in this case we're going to use
5797
04:08:07,500 --> 04:08:08,500
carrier sense multiple axis collision
5798
04:08:09,840 --> 04:08:10,840
avoidance meaning we don't want a
5799
04:08:12,660 --> 04:08:13,660
collision to occur
5800
04:08:14,279 --> 04:08:15,279
in this contention-based media access
5801
04:08:16,620 --> 04:08:17,620
method there are six steps that provide
5802
04:08:19,640 --> 04:08:20,640
Collision free Communication in Wireless
5803
04:08:23,040 --> 04:08:24,040
Lanes specifically now similar to csma
5804
04:08:26,760 --> 04:08:27,760
CD nodes transmit when they have data to
5805
04:08:30,239 --> 04:08:31,239
send however the node takes preventative
5806
04:08:33,180 --> 04:08:34,180
measures basically by sending out a
5807
04:08:35,460 --> 04:08:36,460
jamming signal or a signal to all the
5808
04:08:37,380 --> 04:08:38,380
other computers that tell all the other
5809
04:08:39,600 --> 04:08:40,600
computers that there is uh something to
5810
04:08:42,060 --> 04:08:43,060
be sent
5811
04:08:43,140 --> 04:08:44,140
and therefore no one else is going to
5812
04:08:45,120 --> 04:08:46,120
send anything for a set period of time
5813
04:08:46,979 --> 04:08:47,979
so let's take a look at this in a visual
5814
04:08:49,560 --> 04:08:50,560
way
5815
04:08:51,000 --> 04:08:52,000
so the first step in here like with the
5816
04:08:53,460 --> 04:08:54,460
CD or like with CD as opposed to ca is
5817
04:08:56,399 --> 04:08:57,399
that the transmitting node has data
5818
04:08:59,340 --> 04:09:00,340
descend now the node checks the network
5819
04:09:01,800 --> 04:09:02,800
for any Jam signals being transmitted by
5820
04:09:04,920 --> 04:09:05,920
other nodes basically uh has another
5821
04:09:07,020 --> 04:09:08,020
node already sort of said hey I need to
5822
04:09:09,060 --> 04:09:10,060
send something if not the transmitting
5823
04:09:11,819 --> 04:09:12,819
node
5824
04:09:12,620 --> 04:09:13,620
sends uh its own Jam signal
5825
04:09:18,000 --> 04:09:19,000
saying hey no one else send anything
5826
04:09:21,300 --> 04:09:22,300
because I'm gonna send something right
5827
04:09:22,920 --> 04:09:23,920
now
5828
04:09:23,640 --> 04:09:24,640
then it waits a set period of time to
5829
04:09:26,640 --> 04:09:27,640
allow all the other devices to receive
5830
04:09:28,800 --> 04:09:29,800
this Jam signal and then it transmits
5831
04:09:31,560 --> 04:09:32,560
the data
5832
04:09:32,580 --> 04:09:33,580
now in Step six which is the last step
5833
04:09:35,160 --> 04:09:36,160
the node monitors the network for any
5834
04:09:37,319 --> 04:09:38,319
other Jam signals from other nodes and
5835
04:09:39,779 --> 04:09:40,779
if a signal is detected it halts its
5836
04:09:41,880 --> 04:09:42,880
transmission Waits a delay and then
5837
04:09:44,279 --> 04:09:45,279
tries to transmit again
5838
04:09:47,340 --> 04:09:48,340
this process as you can tell allows
5839
04:09:50,340 --> 04:09:51,340
wireless devices to communicate
5840
04:09:52,800 --> 04:09:53,800
efficiently in a contention-based
5841
04:09:54,960 --> 04:09:55,960
network one in which it's contending for
5842
04:09:57,540 --> 04:09:58,540
the right to send and receive data so
5843
04:10:00,120 --> 04:10:01,120
this allows all nodes to have relatively
5844
04:10:02,279 --> 04:10:03,279
equal access to the media
5845
04:10:04,859 --> 04:10:05,859
now we need to have a an area in which
5846
04:10:08,279 --> 04:10:09,279
all of these are going to contend for
5847
04:10:10,020 --> 04:10:11,020
Access and in a contention domain nodes
5848
04:10:13,020 --> 04:10:14,020
on the network are allowed to compete
5849
04:10:14,460 --> 04:10:15,460
with each other for media access and
5850
04:10:16,560 --> 04:10:17,560
then the collisions might occur as a
5851
04:10:18,779 --> 04:10:19,779
result but this is why a contention
5852
04:10:20,939 --> 04:10:21,939
domain is also considered a collision
5853
04:10:22,920 --> 04:10:23,920
domain because this is where these
5854
04:10:24,779 --> 04:10:25,779
collisions are going to occur now in a
5855
04:10:27,239 --> 04:10:28,239
contention domain switches control the
5856
04:10:30,060 --> 04:10:31,060
size of this domain and in larger
5857
04:10:32,340 --> 04:10:33,340
networks we want to make sure to vot to
5858
04:10:34,439 --> 04:10:35,439
divide these into smaller networks so
5859
04:10:36,239 --> 04:10:37,239
that way we're not having to contend
5860
04:10:37,680 --> 04:10:38,680
with as many devices at the same time
5861
04:10:41,460 --> 04:10:42,460
so
5862
04:10:42,840 --> 04:10:43,840
on the other hand a broadcast domain is
5863
04:10:46,260 --> 04:10:47,260
simply a logical area of the network
5864
04:10:48,180 --> 04:10:49,180
where all the nodes can communicate with
5865
04:10:50,279 --> 04:10:51,279
all the other nodes without having to go
5866
04:10:52,020 --> 04:10:53,020
through a centralized device because of
5867
04:10:54,600 --> 04:10:55,600
this the device we're going to use is
5868
04:10:56,220 --> 04:10:57,220
actually a router which is going to
5869
04:10:57,899 --> 04:10:58,899
control the size of the contention
5870
04:10:59,580 --> 04:11:00,580
domain in a broadcast domain now the
5871
04:11:02,460 --> 04:11:03,460
broadcast domain refers to the set of
5872
04:11:04,920 --> 04:11:05,920
devices that are going to receive
5873
04:11:06,840 --> 04:11:07,840
broadcast data Transmissions from any
5874
04:11:09,060 --> 04:11:10,060
node on that portion of the network
5875
04:11:11,100 --> 04:11:12,100
which is also called a segment
5876
04:11:12,680 --> 04:11:13,680
essentially if a node were to transmit a
5877
04:11:16,020 --> 04:11:17,020
broadcast message the broadcast domain
5878
04:11:18,600 --> 04:11:19,600
dictates where the message is going to
5879
04:11:20,460 --> 04:11:21,460
go
5880
04:11:21,180 --> 04:11:22,180
now in a contention domain if a
5881
04:11:24,359 --> 04:11:25,359
broadcast message were to be transmitted
5882
04:11:26,640 --> 04:11:27,640
there's going to be a greater number of
5883
04:11:28,260 --> 04:11:29,260
collisions as a result of the traffic
5884
04:11:31,020 --> 04:11:32,020
you can have multiple contention domains
5885
04:11:33,899 --> 04:11:34,899
that make up broadcasts that make up a
5886
04:11:37,380 --> 04:11:38,380
broadcast domain so I can have again
5887
04:11:40,140 --> 04:11:41,140
divided by switches two different
5888
04:11:42,420 --> 04:11:43,420
contention domains
5889
04:11:47,520 --> 04:11:48,520
and multiple ones of these can make up a
5890
04:11:50,220 --> 04:11:51,220
larger broadcast domain and
5891
04:11:55,319 --> 04:11:56,319
because these switches are all connected
5892
04:11:57,660 --> 04:11:58,660
by one Central router when one of the
5893
04:12:00,420 --> 04:12:01,420
nodes branching off of one of the
5894
04:12:02,100 --> 04:12:03,100
switches sends a broadcast message
5895
04:12:05,819 --> 04:12:06,819
the router dictates that only the
5896
04:12:08,160 --> 04:12:09,160
connected switch and its devices are
5897
04:12:09,960 --> 04:12:10,960
going to receive that broadcast
5898
04:12:11,279 --> 04:12:12,279
transmission
5899
04:12:13,260 --> 04:12:14,260
so we first talked about defining media
5900
04:12:16,500 --> 04:12:17,500
access basically the rules by which
5901
04:12:19,739 --> 04:12:20,739
devices are allowed to communicate on
5902
04:12:22,620 --> 04:12:23,620
the network we then looked at the two
5903
04:12:24,899 --> 04:12:25,899
broad categories of access or media
5904
04:12:28,199 --> 04:12:29,199
access that we deal with
5905
04:12:29,899 --> 04:12:30,899
contention-based media access meaning
5906
04:12:31,800 --> 04:12:32,800
we're basically fighting
5907
04:12:35,460 --> 04:12:36,460
for the right to access the media or
5908
04:12:39,660 --> 04:12:40,660
controlled media access in which we have
5909
04:12:42,239 --> 04:12:43,239
a central device that decides for us
5910
04:12:45,660 --> 04:12:46,660
we looked at then a couple different
5911
04:12:47,939 --> 04:12:48,939
types of controlled media access these
5912
04:12:51,840 --> 04:12:52,840
are all controlled media access types
5913
04:12:55,699 --> 04:12:56,699
multiplexing which allows us to send
5914
04:12:58,800 --> 04:12:59,800
multiple signals over one media and we
5915
04:13:01,260 --> 04:13:02,260
looked at TDM or time division which
5916
04:13:04,920 --> 04:13:05,920
divides It Up by time and remember this
5917
04:13:06,840 --> 04:13:07,840
is for digital signals and then we
5918
04:13:09,779 --> 04:13:10,779
looked at frequency
5919
04:13:14,279 --> 04:13:15,279
division which allows us to use analog
5920
04:13:17,819 --> 04:13:18,819
signals or Multiplex analog signals
5921
04:13:20,640 --> 04:13:21,640
remember both of these use a device a
5922
04:13:24,060 --> 04:13:25,060
controlling device called a Mox
5923
04:13:26,760 --> 04:13:27,760
or a multiplexer and a d-mox or D
5924
04:13:30,600 --> 04:13:31,600
multiplexer
5925
04:13:32,279 --> 04:13:33,279
we also described polling in which we
5926
04:13:35,220 --> 04:13:36,220
ask are there any devices on this
5927
04:13:37,560 --> 04:13:38,560
network that want to send data but we
5928
04:13:40,020 --> 04:13:41,020
talked about the fact that this can
5929
04:13:41,699 --> 04:13:42,699
actually add more time to the process
5930
04:13:44,640 --> 04:13:45,640
since I have to ask every device before
5931
04:13:47,040 --> 04:13:48,040
I get back to the device that's ready to
5932
04:13:48,720 --> 04:13:49,720
send
5933
04:13:49,439 --> 04:13:50,439
we then looked at two
5934
04:13:52,040 --> 04:13:53,040
contention based media access methods
5935
04:13:59,699 --> 04:14:00,699
carrier sense multiple access Collision
5936
04:14:03,199 --> 04:14:04,199
detection and collision avoidance and
5937
04:14:07,080 --> 04:14:08,080
remember the important thing to know
5938
04:14:08,340 --> 04:14:09,340
here is Collision detection simply has a
5939
04:14:11,520 --> 04:14:12,520
collision occurs and then I just wait
5940
04:14:14,160 --> 04:14:15,160
and I try sending again and this is what
5941
04:14:16,739 --> 04:14:17,739
ethernet really is going to use as
5942
04:14:19,319 --> 04:14:20,319
opposed to collision avoidance
5943
04:14:24,000 --> 04:14:25,000
which is going to be used mostly
5944
04:14:27,300 --> 04:14:28,300
in Wireless situations because I send
5945
04:14:30,239 --> 04:14:31,239
out a jamming signal first
5946
04:14:34,500 --> 04:14:35,500
we then looked at the difference in a
5947
04:14:36,199 --> 04:14:37,199
contention-based domain
5948
04:14:38,580 --> 04:14:39,580
or where we're contending for Access and
5949
04:14:41,160 --> 04:14:42,160
remember that's defined by a switch
5950
04:14:43,140 --> 04:14:44,140
because a switch uh everything connected
5951
04:14:46,260 --> 04:14:47,260
to the switch can contend for Access and
5952
04:14:48,300 --> 04:14:49,300
can have a collision and a broadcast
5953
04:14:50,220 --> 04:14:51,220
domain which is
5954
04:14:52,199 --> 04:14:53,199
created by the router and is simply a
5955
04:14:54,960 --> 04:14:55,960
logical division of all the devices that
5956
04:14:57,420 --> 04:14:58,420
uh one device can contact
5957
04:15:04,430 --> 04:15:05,430
[Music]
5958
04:15:13,340 --> 04:15:14,340
thank you
5959
04:15:24,180 --> 04:15:25,180
network communications signaling methods
5960
04:15:29,520 --> 04:15:30,520
we've talked about digital and analog
5961
04:15:33,560 --> 04:15:34,560
signaling quite a bit but we haven't
5962
04:15:36,000 --> 04:15:37,000
really gone into what that exactly means
5963
04:15:38,220 --> 04:15:39,220
at a waveform level at a basic level and
5964
04:15:42,300 --> 04:15:43,300
so in this module I want to cover some
5965
04:15:44,220 --> 04:15:45,220
of the background information about
5966
04:15:45,779 --> 04:15:46,779
these and outline some of the attributes
5967
04:15:48,180 --> 04:15:49,180
that go along with them
5968
04:15:49,739 --> 04:15:50,739
now this information might not
5969
04:15:51,660 --> 04:15:52,660
specifically be on the exam but I think
5970
04:15:54,899 --> 04:15:55,899
it's still good background information
5971
04:15:56,100 --> 04:15:57,100
to understand anyway
5972
04:15:58,199 --> 04:15:59,199
so uh in this module we're first going
5973
04:16:00,840 --> 04:16:01,840
to Define what a signal is and what
5974
04:16:03,720 --> 04:16:04,720
analog is
5975
04:16:05,279 --> 04:16:06,279
we're then going to talk about the
5976
04:16:07,199 --> 04:16:08,199
attributes of an analog signal
5977
04:16:11,640 --> 04:16:12,640
well then take this and talk about a
5978
04:16:14,520 --> 04:16:15,520
digital signal different from analog and
5979
04:16:17,939 --> 04:16:18,939
a digital data transmission or how this
5980
04:16:20,640 --> 04:16:21,640
digital Signa is transmitted
5981
04:16:22,920 --> 04:16:23,920
we're also going to Define modulation
5982
04:16:25,920 --> 04:16:26,920
and outline the Way digital signals are
5983
04:16:29,340 --> 04:16:30,340
modulated and modulation really has to
5984
04:16:31,979 --> 04:16:32,979
do with uh length or making sure that a
5985
04:16:35,340 --> 04:16:36,340
signal can be broadcast or sent over a
5986
04:16:39,239 --> 04:16:40,239
very long or large
5987
04:16:41,279 --> 04:16:42,279
area
5988
04:16:42,600 --> 04:16:43,600
or distance
5989
04:16:44,760 --> 04:16:45,760
finally we'll look at Digital Signal
5990
04:16:47,040 --> 04:16:48,040
reference methods how we know when the
5991
04:16:50,460 --> 04:16:51,460
message begins and when it ends and
5992
04:16:53,040 --> 04:16:54,040
finally wind up talking about Digital
5993
04:16:55,500 --> 04:16:56,500
Data units or the unit of measurements
5994
04:16:58,020 --> 04:16:59,020
that we hear often when we're referring
5995
04:16:59,819 --> 04:17:00,819
to Digital Data such as kilobytes and
5996
04:17:02,399 --> 04:17:03,399
megabytes so at its most basic level a
5997
04:17:06,239 --> 04:17:07,239
signal is simply data or information
5998
04:17:08,760 --> 04:17:09,760
that is translated into measurable
5999
04:17:12,380 --> 04:17:13,380
transmittable and receivable formats
6000
04:17:16,439 --> 04:17:17,439
meaning that it is what allows us to
6001
04:17:19,380 --> 04:17:20,380
transmit and receive data
6002
04:17:21,479 --> 04:17:22,479
now an analog signal is a signal that
6003
04:17:24,420 --> 04:17:25,420
carries data in a continuous stream or a
6004
04:17:28,560 --> 04:17:29,560
waveform via either electromagnetic or
6005
04:17:32,160 --> 04:17:33,160
Optical energy and this energy can come
6006
04:17:34,800 --> 04:17:35,800
from many different sources uh
6007
04:17:38,160 --> 04:17:39,160
such as a electric current
6008
04:17:40,979 --> 04:17:41,979
and the analog waveforms characteristics
6009
04:17:43,680 --> 04:17:44,680
determine the information that it
6010
04:17:45,960 --> 04:17:46,960
contains because the analog signal will
6011
04:17:48,600 --> 04:17:49,600
oscillate between minimum and maximum
6012
04:17:52,560 --> 04:17:53,560
values over time
6013
04:17:55,140 --> 04:17:56,140
basically the analog signal has many
6014
04:17:58,140 --> 04:17:59,140
attributes to it and it can be read in
6015
04:18:00,180 --> 04:18:01,180
many different ways depending on the
6016
04:18:03,720 --> 04:18:04,720
values and the information in the
6017
04:18:05,399 --> 04:18:06,399
signals given
6018
04:18:08,120 --> 04:18:09,120
now this analog signal as I just
6019
04:18:11,100 --> 04:18:12,100
mentioned is many different possible
6020
04:18:12,660 --> 04:18:13,660
values depending on the characteristics
6021
04:18:15,000 --> 04:18:16,000
and how that signal is being read now
6022
04:18:17,340 --> 04:18:18,340
the characteristics of an analog
6023
04:18:19,260 --> 04:18:20,260
waveform can be described using the
6024
04:18:21,899 --> 04:18:22,899
following terms these won't necessarily
6025
04:18:24,359 --> 04:18:25,359
appear on the exam but they're good
6026
04:18:25,800 --> 04:18:26,800
background information for you anyway
6027
04:18:27,239 --> 04:18:28,239
first we have the crest or the peak of
6028
04:18:30,239 --> 04:18:31,239
the signal this is the distance from the
6029
04:18:32,939 --> 04:18:33,939
midpoint to the topmost part of the wave
6030
04:18:35,760 --> 04:18:36,760
and when we talk about the midpoint we
6031
04:18:37,560 --> 04:18:38,560
talk about this line that's sort of
6032
04:18:39,180 --> 04:18:40,180
going through
6033
04:18:40,279 --> 04:18:41,279
inversely the trough is the distance
6034
04:18:43,260 --> 04:18:44,260
from the midpoint to the bottom most
6035
04:18:45,300 --> 04:18:46,300
portion of the wave
6036
04:18:46,739 --> 04:18:47,739
now the next term I want to talk about
6037
04:18:48,120 --> 04:18:49,120
is amplitude amplitude is exactly one
6038
04:18:51,960 --> 04:18:52,960
half the distance between the crest and
6039
04:18:54,840 --> 04:18:55,840
the trough of the wave so it would
6040
04:18:57,359 --> 04:18:58,359
either be this could be the what it's
6041
04:19:00,000 --> 04:19:01,000
measured it could be the amplitude
6042
04:19:01,020 --> 04:19:02,020
alternatively
6043
04:19:02,520 --> 04:19:03,520
this could be the amplitude
6044
04:19:04,560 --> 04:19:05,560
and the cycle is one complete
6045
04:19:06,840 --> 04:19:07,840
oscillation of the wave from start to
6046
04:19:09,479 --> 04:19:10,479
finish changing from one state to
6047
04:19:11,760 --> 04:19:12,760
another and Back Again basically from
6048
04:19:14,040 --> 04:19:15,040
the midpoint going up until we get to
6049
04:19:16,939 --> 04:19:17,939
the next midpoint
6050
04:19:19,859 --> 04:19:20,859
after it goes down
6051
04:19:22,020 --> 04:19:23,020
now the wavelength is determined by the
6052
04:19:25,080 --> 04:19:26,080
distance between two consecutive troughs
6053
04:19:28,439 --> 04:19:29,439
or Peaks so here we're measuring the
6054
04:19:30,840 --> 04:19:31,840
wavelength between two troughs we could
6055
04:19:33,239 --> 04:19:34,239
also measure it between two peaks like
6056
04:19:36,180 --> 04:19:37,180
so
6057
04:19:37,260 --> 04:19:38,260
now the frequency also called the period
6058
04:19:40,319 --> 04:19:41,319
of the wave is the number of complete
6059
04:19:42,899 --> 04:19:43,899
cycles per second in a wave this is
6060
04:19:46,380 --> 04:19:47,380
generally measured
6061
04:19:47,760 --> 04:19:48,760
in hertz such as gigahertz or megahertz
6062
04:19:51,120 --> 04:19:52,120
now the last term is the phase of the
6063
04:19:54,300 --> 04:19:55,300
wave
6064
04:19:55,140 --> 04:19:56,140
the phase is the relationship of the
6065
04:19:58,439 --> 04:19:59,439
Cycles beginning to a fixed point in
6066
04:20:01,500 --> 04:20:02,500
time meaning if two waves with the same
6067
04:20:04,859 --> 04:20:05,859
frequency are transmitted at the same
6068
04:20:07,920 --> 04:20:08,920
time
6069
04:20:09,120 --> 04:20:10,120
they are said to be in phase and two
6070
04:20:12,060 --> 04:20:13,060
that are purposely offset from each
6071
04:20:13,979 --> 04:20:14,979
other or if they have different
6072
04:20:16,020 --> 04:20:17,020
frequencies like these do they will be
6073
04:20:19,680 --> 04:20:20,680
out of phase
6074
04:20:21,359 --> 04:20:22,359
the device that plots the amplitude of
6075
04:20:24,120 --> 04:20:25,120
an analog signal what would show you
6076
04:20:26,460 --> 04:20:27,460
this wave is called an oscilloscope
6077
04:20:30,239 --> 04:20:31,239
and you may have seen this perhaps at a
6078
04:20:33,180 --> 04:20:34,180
store or even on TV and we can measure
6079
04:20:36,359 --> 04:20:37,359
waves of all sorts of things for
6080
04:20:38,040 --> 04:20:39,040
instance sound might be a wave that
6081
04:20:40,020 --> 04:20:41,020
you've seen when you're running a
6082
04:20:42,000 --> 04:20:43,000
program on your computer this gives you
6083
04:20:44,460 --> 04:20:45,460
a real-time view of the analog waveforms
6084
04:20:47,279 --> 04:20:48,279
and its shape if we've just as we've
6085
04:20:49,800 --> 04:20:50,800
just described now unlike analog signals
6086
04:20:53,279 --> 04:20:54,279
which can have many different values
6087
04:20:55,020 --> 04:20:56,020
assigned to them Digital Data
6088
04:20:57,540 --> 04:20:58,540
Transmissions utilize voltage
6089
04:21:00,060 --> 04:21:01,060
differences represented either by ones
6090
04:21:02,819 --> 04:21:03,819
and zeros these ones and zeros are what
6091
04:21:06,660 --> 04:21:07,660
make up all of the information
6092
04:21:09,479 --> 04:21:10,479
when there is a presence of a signal or
6093
04:21:12,720 --> 04:21:13,720
voltage meaning that it is on it
6094
04:21:15,180 --> 04:21:16,180
translates to one
6095
04:21:17,100 --> 04:21:18,100
and a lack of voltage or an absence of
6096
04:21:19,680 --> 04:21:20,680
this signal translates to zero now in
6097
04:21:23,160 --> 04:21:24,160
computer networks digital waveforms can
6098
04:21:25,859 --> 04:21:26,859
switch between two voltage levels
6099
04:21:27,779 --> 04:21:28,779
depending on its relation to the ground
6100
04:21:30,899 --> 04:21:31,899
if you recall what that is
6101
04:21:33,060 --> 04:21:34,060
now because digital signals utilize
6102
04:21:35,699 --> 04:21:36,699
voltage to represent its values of ones
6103
04:21:38,279 --> 04:21:39,279
and zeros this is also called The
6104
04:21:41,040 --> 04:21:42,040
Logical state of the data
6105
04:21:45,540 --> 04:21:46,540
each bit or binary digit takes a
6106
04:21:50,220 --> 04:21:51,220
predetermined period of time to transmit
6107
04:21:53,819 --> 04:21:54,819
and bit patterns are used to establish
6108
04:21:57,300 --> 04:21:58,300
the start and the stop of the sequence
6109
04:21:59,580 --> 04:22:00,580
and the sink clocks which allows the
6110
04:22:03,359 --> 04:22:04,359
receiver and the sender to be on
6111
04:22:05,399 --> 04:22:06,399
basically the same page the sender and
6112
04:22:08,100 --> 04:22:09,100
the receiver have to then synchronize
6113
04:22:10,020 --> 04:22:11,020
these clocks to ensure proper reception
6114
04:22:12,660 --> 04:22:13,660
or receipt of the data now there are a
6115
04:22:15,899 --> 04:22:16,899
couple different ways that we encode in
6116
04:22:18,779 --> 04:22:19,779
order to allow devices to tell which bit
6117
04:22:21,300 --> 04:22:22,300
is what in other words to tell it when
6118
04:22:24,180 --> 04:22:25,180
it starts and when it ends
6119
04:22:26,460 --> 04:22:27,460
the first method I want to look at is
6120
04:22:28,020 --> 04:22:29,020
called on off keying this looks at the
6121
04:22:31,620 --> 04:22:32,620
voltage change
6122
04:22:33,120 --> 04:22:34,120
from one state to the other
6123
04:22:39,540 --> 04:22:40,540
within a pre-specified interval
6124
04:22:50,040 --> 04:22:51,040
which is represented by the binary digit
6125
04:22:52,560 --> 04:22:53,560
one and the lack of voltage or no
6126
04:22:55,739 --> 04:22:56,739
voltage is represented by zero as we
6127
04:22:57,779 --> 04:22:58,779
just saw now the synchronization between
6128
04:23:00,180 --> 04:23:01,180
the sender and the receiver occurs with
6129
04:23:02,760 --> 04:23:03,760
the receiver waiting for a series of
6130
04:23:05,880 --> 04:23:06,880
ones
6131
04:23:09,840 --> 04:23:10,840
because of this there is a potential for
6132
04:23:12,120 --> 04:23:13,120
problems to arise especially when the
6133
04:23:14,399 --> 04:23:15,399
sender has a long series of ones to
6134
04:23:17,100 --> 04:23:18,100
transmit within the data this means that
6135
04:23:20,040 --> 04:23:21,040
it could take a long while for the
6136
04:23:22,439 --> 04:23:23,439
sender and the receiver to synchronize
6137
04:23:24,479 --> 04:23:25,479
their clocks together
6138
04:23:25,979 --> 04:23:26,979
in the event that the clocks are not
6139
04:23:27,660 --> 04:23:28,660
sync then there's a high probability for
6140
04:23:30,000 --> 04:23:31,000
data corruption as the receiver can't
6141
04:23:34,560 --> 04:23:35,560
determine how many ones and zeros have
6142
04:23:37,319 --> 04:23:38,319
to be transmitted now there are two
6143
04:23:39,359 --> 04:23:40,359
variations of on and off keying I have
6144
04:23:41,880 --> 04:23:42,880
listed here
6145
04:23:42,899 --> 04:23:43,899
one is called the non-return to zero
6146
04:23:45,300 --> 04:23:46,300
variation and the other is the
6147
04:23:47,640 --> 04:23:48,640
non-return to zero inverted
6148
04:23:49,979 --> 04:23:50,979
this type of data encoding scheme is
6149
04:23:52,739 --> 04:23:53,739
typically used over serial ports and
6150
04:23:55,979 --> 04:23:56,979
fairly slow connections
6151
04:23:58,380 --> 04:23:59,380
I'm mentioning these because uh they're
6152
04:24:01,739 --> 04:24:02,739
good to know but you won't have to worry
6153
04:24:04,439 --> 04:24:05,439
about these for the exam
6154
04:24:07,500 --> 04:24:08,500
now the next encoding scheme a little
6155
04:24:09,840 --> 04:24:10,840
more popular perhaps is called
6156
04:24:11,399 --> 04:24:12,399
Manchester encoding this scheme was
6157
04:24:13,979 --> 04:24:14,979
developed in order to address some of
6158
04:24:15,720 --> 04:24:16,720
the downfalls that we saw with on and
6159
04:24:18,479 --> 04:24:19,479
off keying firstly Manchester encoding
6160
04:24:21,779 --> 04:24:22,779
uses voltage differences to represent
6161
04:24:24,420 --> 04:24:25,420
both binary digits so instead of just
6162
04:24:27,420 --> 04:24:28,420
having one which is represented by a
6163
04:24:30,720 --> 04:24:31,720
voltage and then zero which has no
6164
04:24:32,580 --> 04:24:33,580
voltage both zero and one have voltages
6165
04:24:36,060 --> 04:24:37,060
the way it does this is it works by
6166
04:24:39,120 --> 04:24:40,120
assigning the voltage change from
6167
04:24:41,279 --> 04:24:42,279
positive to ground
6168
04:24:44,880 --> 04:24:45,880
or the binary digit 0 and a negative to
6169
04:24:48,779 --> 04:24:49,779
positive change equals the binary digit
6170
04:24:51,960 --> 04:24:52,960
one so
6171
04:24:53,939 --> 04:24:54,939
positive to Ground Zero
6172
04:24:57,300 --> 04:24:58,300
negative or ground to positive
6173
04:25:02,340 --> 04:25:03,340
equals one
6174
04:25:04,859 --> 04:25:05,859
this effectively eliminates the issue of
6175
04:25:08,399 --> 04:25:09,399
too many one bits being transmitted and
6176
04:25:11,699 --> 04:25:12,699
throwing off the synchronization as we
6177
04:25:13,920 --> 04:25:14,920
saw with on and off King which relies on
6178
04:25:16,080 --> 04:25:17,080
those one bits in order to sync up the
6179
04:25:17,699 --> 04:25:18,699
clocks
6180
04:25:18,840 --> 04:25:19,840
okay so modulation is the process of
6181
04:25:23,520 --> 04:25:24,520
taking a weaker lower frequency analog
6182
04:25:26,819 --> 04:25:27,819
signal that can't travel large distances
6183
04:25:29,279 --> 04:25:30,279
and superimposing the signal over a
6184
04:25:32,460 --> 04:25:33,460
stronger higher frequency called a
6185
04:25:35,880 --> 04:25:36,880
carrier signal
6186
04:25:37,920 --> 04:25:38,920
the carrier signal being constant takes
6187
04:25:41,520 --> 04:25:42,520
on the attributes of the analog signal
6188
04:25:45,000 --> 04:25:46,000
and it's shaped by either the phase
6189
04:25:47,100 --> 04:25:48,100
amplitude or the frequency the resulting
6190
04:25:51,000 --> 04:25:52,000
signal then has characteristics of both
6191
04:25:54,420 --> 04:25:55,420
the original signal and the carrier
6192
04:25:57,000 --> 04:25:58,000
signal that process this is called
6193
04:26:01,100 --> 04:26:02,100
modulation and when receiving and when
6194
04:26:04,500 --> 04:26:05,500
the receiving end decodes the signal by
6195
04:26:08,040 --> 04:26:09,040
separating these two signals the carrier
6196
04:26:11,580 --> 04:26:12,580
and the data
6197
04:26:14,880 --> 04:26:15,880
the process is called
6198
04:26:16,979 --> 04:26:17,979
demodulation
6199
04:26:19,560 --> 04:26:20,560
so again we have demodulation
6200
04:26:25,080 --> 04:26:26,080
which would basically
6201
04:26:27,300 --> 04:26:28,300
take these away from one another and
6202
04:26:29,819 --> 04:26:30,819
modulation which puts them together
6203
04:26:35,460 --> 04:26:36,460
devices that perform this operation
6204
04:26:37,859 --> 04:26:38,859
you've probably heard of before they're
6205
04:26:40,199 --> 04:26:41,199
called modems
6206
04:26:42,600 --> 04:26:43,600
and a modem is known for its ability to
6207
04:26:46,340 --> 04:26:47,340
modulate and demodulate hence the name
6208
04:26:51,359 --> 04:26:52,359
a modem is in effect a type of codec
6209
04:26:54,300 --> 04:26:55,300
which is a software or Hardware that
6210
04:26:57,560 --> 04:26:58,560
translates digital
6211
04:27:04,020 --> 04:27:05,020
to analog formats and back this is an
6212
04:27:08,699 --> 04:27:09,699
important thing to know for the exam a
6213
04:27:11,720 --> 04:27:12,720
DAC
6214
04:27:13,500 --> 04:27:14,500
is a digital to analog codec
6215
04:27:17,100 --> 04:27:18,100
and in
6216
04:27:18,739 --> 04:27:19,739
ADC as you guessed it is an analog to
6217
04:27:22,739 --> 04:27:23,739
digital codec
6218
04:27:25,920 --> 04:27:26,920
both of these exist in a modem
6219
04:27:29,159 --> 04:27:30,159
now this is it in analog terms but
6220
04:27:31,979 --> 04:27:32,979
digital modulation is also required
6221
04:27:35,340 --> 04:27:36,340
which allows the digital signal to
6222
04:27:38,040 --> 04:27:39,040
travel along distances and demodulation
6223
04:27:41,220 --> 04:27:42,220
is the representation of Digital Data in
6224
04:27:44,880 --> 04:27:45,880
an analog format for transmission over
6225
04:27:47,580 --> 04:27:48,580
those longer distances so the analog
6226
04:27:50,279 --> 04:27:51,279
signal has a characteristic changed to
6227
04:27:53,760 --> 04:27:54,760
signify the difference between logical
6228
04:27:56,580 --> 04:27:57,580
states of the digital signal this is a
6229
04:27:59,699 --> 04:28:00,699
fairly simple as digital signals again
6230
04:28:02,279 --> 04:28:03,279
only have two states one and zero and so
6231
04:28:06,239 --> 04:28:07,239
the analog waveform needs only be
6232
04:28:09,420 --> 04:28:10,420
changed or modulated in one way such as
6233
04:28:13,680 --> 04:28:14,680
the graphic here the frequency is
6234
04:28:15,899 --> 04:28:16,899
changed where the higher frequency
6235
04:28:17,580 --> 04:28:18,580
represents one bits and the lower
6236
04:28:20,460 --> 04:28:21,460
frequency represents zero bits in this
6237
04:28:24,120 --> 04:28:25,120
way I can convert this Digital Signal
6238
04:28:27,659 --> 04:28:28,659
into an analog one 1 in order to
6239
04:28:30,540 --> 04:28:31,540
transfer transfer transmit it over a
6240
04:28:33,359 --> 04:28:34,359
long distance now there are various
6241
04:28:35,520 --> 04:28:36,520
methods to modulate the digital signal
6242
04:28:38,520 --> 04:28:39,520
depending on what part of the analog
6243
04:28:40,859 --> 04:28:41,859
waveform is being changed the first one
6244
04:28:43,859 --> 04:28:44,859
is called ask or amplitude shift key
6245
04:28:47,819 --> 04:28:48,819
modulation here only the amplitude of
6246
04:28:51,600 --> 04:28:52,600
the wave is modulated and remember the
6247
04:28:54,239 --> 04:28:55,239
amplitude is the distance
6248
04:28:59,100 --> 04:29:00,100
between a peak or a trough in the
6249
04:29:01,800 --> 04:29:02,800
midpoint
6250
04:29:05,279 --> 04:29:06,279
and the result of this can only be one
6251
04:29:07,739 --> 04:29:08,739
or zero the next method is called
6252
04:29:10,859 --> 04:29:11,859
frequency shift key here the frequency
6253
04:29:13,979 --> 04:29:14,979
is modulated to only represent one or
6254
04:29:17,159 --> 04:29:18,159
zero as opposed to the amplitude and
6255
04:29:19,500 --> 04:29:20,500
remember the frequency is the amount
6256
04:29:22,680 --> 04:29:23,680
times we have this wave over a certain
6257
04:29:25,439 --> 04:29:26,439
period of time
6258
04:29:28,199 --> 04:29:29,199
we also have something called binary
6259
04:29:30,120 --> 04:29:31,120
phase shift key in which case the phase
6260
04:29:33,960 --> 04:29:34,960
of the wave is changed and remember the
6261
04:29:36,359 --> 04:29:37,359
phase would be if I have 2 next to each
6262
04:29:39,000 --> 04:29:40,000
other the difference between those
6263
04:29:41,399 --> 04:29:42,399
and then I have quadrature phase shift
6264
04:29:44,279 --> 04:29:45,279
keying here the phase is changed as well
6265
04:29:47,100 --> 04:29:48,100
but we can actually have two logical
6266
04:29:49,859 --> 04:29:50,859
States at a time
6267
04:29:51,420 --> 04:29:52,420
for instance zero zero zero one one zero
6268
04:29:55,140 --> 04:29:56,140
or one one this method actually allows
6269
04:29:57,840 --> 04:29:58,840
for data uh to be more secure when it's
6270
04:30:02,159 --> 04:30:03,159
transmitted so this is a more secure
6271
04:30:04,439 --> 04:30:05,439
method
6272
04:30:06,540 --> 04:30:07,540
finally there's something called
6273
04:30:08,180 --> 04:30:09,180
quadrature amplitude modulation and in
6274
04:30:12,300 --> 04:30:13,300
this case I can also have more than two
6275
04:30:14,640 --> 04:30:15,640
states at a time but what I'm shifting
6276
04:30:17,279 --> 04:30:18,279
here instead of the phase only is I'm
6277
04:30:20,220 --> 04:30:21,220
also Shifting the amplitude and so these
6278
04:30:23,580 --> 04:30:24,580
are both combined into one different
6279
04:30:25,680 --> 04:30:26,680
modulating wave now in order to
6280
04:30:28,340 --> 04:30:29,340
demodulate these once I've modulated
6281
04:30:30,779 --> 04:30:31,779
them
6282
04:30:31,680 --> 04:30:32,680
there must be a reference to
6283
04:30:33,899 --> 04:30:34,899
differentiate the data from the rest of
6284
04:30:35,760 --> 04:30:36,760
the signal now there are two digital
6285
04:30:38,399 --> 04:30:39,399
signal reference methods that can be
6286
04:30:40,560 --> 04:30:41,560
used the first reference method is
6287
04:30:42,840 --> 04:30:43,840
called differential demodulation
6288
04:30:45,840 --> 04:30:46,840
this takes the modulated and the
6289
04:30:48,960 --> 04:30:49,960
demodulated signals
6290
04:30:51,120 --> 04:30:52,120
and Compares them the output then
6291
04:30:54,120 --> 04:30:55,120
becomes one mod one signal which is the
6292
04:30:57,779 --> 04:30:58,779
data
6293
04:30:58,859 --> 04:30:59,859
there's also something called a
6294
04:31:01,140 --> 04:31:02,140
single-ended this method instead of
6295
04:31:03,600 --> 04:31:04,600
using two different the modulated and
6296
04:31:06,659 --> 04:31:07,659
the demodulated singles signals uses the
6297
04:31:09,840 --> 04:31:10,840
ground as a reference point and the
6298
04:31:12,239 --> 04:31:13,239
resultant information then becomes the
6299
04:31:14,520 --> 04:31:15,520
data now again if this is a little
6300
04:31:16,500 --> 04:31:17,500
confusing don't worry about it it's not
6301
04:31:18,479 --> 04:31:19,479
going to come up on the exam I just want
6302
04:31:20,939 --> 04:31:21,939
to cover this to give you a broad basis
6303
04:31:23,100 --> 04:31:24,100
outline of what we're talking about here
6304
04:31:26,580 --> 04:31:27,580
now while there is very good possibility
6305
04:31:28,800 --> 04:31:29,800
that you've probably heard of some of
6306
04:31:30,060 --> 04:31:31,060
these data units I'm about to mention at
6307
04:31:31,739 --> 04:31:32,739
one time or another it's really
6308
04:31:33,359 --> 04:31:34,359
important that you really understand
6309
04:31:34,620 --> 04:31:35,620
them in their actual quantities now
6310
04:31:37,500 --> 04:31:38,500
originally before computers became
6311
04:31:39,420 --> 04:31:40,420
household items and now nearly
6312
04:31:41,760 --> 04:31:42,760
ubiquitous computer Engineers came up
6313
04:31:44,159 --> 04:31:45,159
with these measurements of data and it
6314
04:31:46,439 --> 04:31:47,439
was pretty straightforward as we've
6315
04:31:48,540 --> 04:31:49,540
mentioned before in computer systems and
6316
04:31:50,220 --> 04:31:51,220
networking data is stored in binary
6317
04:31:53,279 --> 04:31:54,279
digits or bits and a single bit is
6318
04:31:56,819 --> 04:31:57,819
either a zero or a one this is the most
6319
04:32:00,120 --> 04:32:01,120
basic form of measurement zero one being
6320
04:32:02,939 --> 04:32:03,939
no power
6321
04:32:05,520 --> 04:32:06,520
or power
6322
04:32:09,840 --> 04:32:10,840
a lesser-known term but still cool
6323
04:32:12,239 --> 04:32:13,239
nonetheless is that two bits together
6324
04:32:14,580 --> 04:32:15,580
form a crumb
6325
04:32:16,800 --> 04:32:17,800
bits contain a nibble and a bits
6326
04:32:20,640 --> 04:32:21,640
together a byte that's how we got there
6327
04:32:23,220 --> 04:32:24,220
bits crumbs nibbles bites now depending
6328
04:32:26,819 --> 04:32:27,819
on the processor you have
6329
04:32:28,739 --> 04:32:29,739
a word would either be 16 32 or 64 bits
6330
04:32:34,380 --> 04:32:35,380
we generally don't see 16-bit processors
6331
04:32:37,020 --> 04:32:38,020
anymore so generally speaking a word is
6332
04:32:40,080 --> 04:32:41,080
either going to be 32 bits or 64 bits
6333
04:32:42,540 --> 04:32:43,540
this doesn't mean a word that you've
6334
04:32:44,640 --> 04:32:45,640
written on your word processor but a
6335
04:32:47,399 --> 04:32:48,399
unit of measurement just like byte is
6336
04:32:50,340 --> 04:32:51,340
now in most places
6337
04:32:52,800 --> 04:32:53,800
Hilo is a thousand such as kilometers
6338
04:32:57,260 --> 04:32:58,260
and uh in one thousand such as
6339
04:33:00,840 --> 04:33:01,840
kilometers means one thousand meters
6340
04:33:03,359 --> 04:33:04,359
while this is true in networking it
6341
04:33:05,400 --> 04:33:06,400
becomes slightly more complicated
6342
04:33:07,561 --> 04:33:08,561
because some sources Define a key a
6343
04:33:10,859 --> 04:33:11,859
kilobit as
6344
04:33:13,279 --> 04:33:14,279
1024 bits While others might Define a
6345
04:33:16,439 --> 04:33:17,439
kilobit as 1024 bytes
6346
04:33:20,160 --> 04:33:21,160
one of the reasons for this confusion is
6347
04:33:23,879 --> 04:33:24,879
and you can see right here how we get
6348
04:33:25,680 --> 04:33:26,680
that 1024
6349
04:33:27,600 --> 04:33:28,600
2 to the 10th bytes and one of the
6350
04:33:30,420 --> 04:33:31,420
confusion the reason for this confusion
6351
04:33:32,100 --> 04:33:33,100
of bits versus bytes is because of the
6352
04:33:35,459 --> 04:33:36,459
little B versus the Big B so here is a
6353
04:33:38,760 --> 04:33:39,760
fairly easy breakdown
6354
04:33:41,820 --> 04:33:42,820
that nearly anywhere you go and more
6355
04:33:43,680 --> 04:33:44,680
importantly on the exam is going to
6356
04:33:45,779 --> 04:33:46,779
allow you to have a perfect
6357
04:33:46,619 --> 04:33:47,619
understanding of how much data we're
6358
04:33:48,420 --> 04:33:49,420
actually talking about
6359
04:33:49,680 --> 04:33:50,680
this chart specifies how the breakdown
6360
04:33:52,740 --> 04:33:53,740
of binary data is mathematically
6361
04:33:55,439 --> 04:33:56,439
calculated and this binary is a base 2
6362
04:33:58,980 --> 04:33:59,980
system
6363
04:34:01,740 --> 04:34:02,740
and we'll talk more about that when we
6364
04:34:03,480 --> 04:34:04,480
get into binary and creating binary
6365
04:34:06,719 --> 04:34:07,719
um
6366
04:34:07,379 --> 04:34:08,379
uh numbers like IP addresses and why is
6367
04:34:11,939 --> 04:34:12,939
it base two because we only have two
6368
04:34:13,379 --> 04:34:14,379
options a one and a zero
6369
04:34:17,039 --> 04:34:18,039
which is a bit and remember eight bits
6370
04:34:19,619 --> 04:34:20,619
go into a byte so this chart mainly
6371
04:34:22,141 --> 04:34:23,141
demonstrates how that numbering system
6372
04:34:23,760 --> 04:34:24,760
works the magic number I really want you
6373
04:34:25,980 --> 04:34:26,980
to pay attention to is 10 24. that's the
6374
04:34:29,100 --> 04:34:30,100
number of bytes in a kilobyte the number
6375
04:34:31,320 --> 04:34:32,320
of kilobytes in a megabyte the number of
6376
04:34:33,420 --> 04:34:34,420
megabytes in a gigabyte the number
6377
04:34:35,580 --> 04:34:36,580
gigabytes in a terabyte so on and so
6378
04:34:38,699 --> 04:34:39,699
forth now you're not going to be asked
6379
04:34:40,561 --> 04:34:41,561
to calculate this necessarily but it's
6380
04:34:43,199 --> 04:34:44,199
good to know nonetheless
6381
04:34:45,779 --> 04:34:46,779
all right
6382
04:34:47,879 --> 04:34:48,879
so we just talked about a signal and
6383
04:34:50,820 --> 04:34:51,820
what analog means the signal being how
6384
04:34:53,879 --> 04:34:54,879
that data is sent modified and received
6385
04:34:57,600 --> 04:34:58,600
and then analog being that it can have
6386
04:35:00,420 --> 04:35:01,420
many different values
6387
04:35:02,340 --> 04:35:03,340
we looked at the attributes of a analog
6388
04:35:05,160 --> 04:35:06,160
signal including amplitude
6389
04:35:10,219 --> 04:35:11,219
Peak a trough
6390
04:35:15,480 --> 04:35:16,480
frequency and so on
6391
04:35:18,480 --> 04:35:19,480
we also looked at a digital signal and
6392
04:35:20,939 --> 04:35:21,939
Digital Data Transmissions remembering
6393
04:35:23,520 --> 04:35:24,520
that a digital signal can only have
6394
04:35:25,859 --> 04:35:26,859
generally two values a one and a zero
6395
04:35:30,420 --> 04:35:31,420
and depending on whether we're comparing
6396
04:35:32,400 --> 04:35:33,400
it to each its own or to the ground we
6397
04:35:35,279 --> 04:35:36,279
have different digital data transmission
6398
04:35:36,959 --> 04:35:37,959
methods we also looked at modulating
6399
04:35:40,020 --> 04:35:41,020
which allows us to send a signal over a
6400
04:35:43,859 --> 04:35:44,859
more powerful carrier signal
6401
04:35:47,340 --> 04:35:48,340
in order to allow it to travel long
6402
04:35:50,160 --> 04:35:51,160
distances
6403
04:35:52,680 --> 04:35:53,680
we looked at Digital Signal modulation
6404
04:35:55,561 --> 04:35:56,561
techniques perhaps we got a little too
6405
04:35:58,080 --> 04:35:59,080
involved in it
6406
04:35:59,400 --> 04:36:00,400
and we talked about how then we can
6407
04:36:02,520 --> 04:36:03,520
convert these Digital Signal into a
6408
04:36:06,061 --> 04:36:07,061
analog signal for sending over data and
6409
04:36:09,600 --> 04:36:10,600
then how we demodulate it back and we
6410
04:36:12,240 --> 04:36:13,240
talked about the device doing this is
6411
04:36:14,039 --> 04:36:15,039
called a modem which modulates and
6412
04:36:17,039 --> 04:36:18,039
demodulates
6413
04:36:18,359 --> 04:36:19,359
we also described Digital Signal
6414
04:36:20,699 --> 04:36:21,699
referencing methods in other words how
6415
04:36:23,160 --> 04:36:24,160
it knows where the signal begins and
6416
04:36:26,100 --> 04:36:27,100
where it ends
6417
04:36:31,439 --> 04:36:32,439
finally we described the Digital Data
6418
04:36:33,959 --> 04:36:34,959
units specifically I wanted you to pay
6419
04:36:36,299 --> 04:36:37,299
attention to the fact that one bit
6420
04:36:39,299 --> 04:36:40,299
equals the fact that 8 Bits equal one
6421
04:36:43,859 --> 04:36:44,859
byte
6422
04:36:45,779 --> 04:36:46,779
and the fact that 10
6423
04:36:48,680 --> 04:36:49,680
1024 bits
6424
04:36:52,020 --> 04:36:53,020
are in one
6425
04:36:55,920 --> 04:36:56,920
kilobit
6426
04:36:57,539 --> 04:36:58,539
or 1024 bytes are in one kilobyte
6427
04:37:08,360 --> 04:37:09,360
[Music]
6428
04:37:28,500 --> 04:37:29,500
Network protocols and services
6429
04:37:31,680 --> 04:37:32,680
common Network ports and protocols
6430
04:37:35,400 --> 04:37:36,400
all right now we start getting into what
6431
04:37:37,379 --> 04:37:38,379
I think is the fun stuff in this network
6432
04:37:39,660 --> 04:37:40,660
plus exam in some ways it's also where a
6433
04:37:42,539 --> 04:37:43,539
blue bulk of the questions are going to
6434
04:37:44,039 --> 04:37:45,039
come from by the end of this module
6435
04:37:47,580 --> 04:37:48,580
you're going to be able to say what each
6436
04:37:49,740 --> 04:37:50,740
of these numbers represents in terms of
6437
04:37:52,379 --> 04:37:53,379
a protocol now if you took the a plus
6438
04:37:54,660 --> 04:37:55,660
exam and I hope you did you probably
6439
04:37:56,939 --> 04:37:57,939
recall some of these from there so this
6440
04:37:59,160 --> 04:38:00,160
might be a bit of a recap for you but
6441
04:38:01,680 --> 04:38:02,680
that's okay it never hurts to go over
6442
04:38:03,061 --> 04:38:04,061
this stuff again especially because it
6443
04:38:05,340 --> 04:38:06,340
just always pops up on the exam and as
6444
04:38:07,439 --> 04:38:08,439
far as knowing stuff this is one of
6445
04:38:09,959 --> 04:38:10,959
those things that you just have to know
6446
04:38:11,520 --> 04:38:12,520
these these Protocols are what you
6447
04:38:13,141 --> 04:38:14,141
really have to know we're going to talk
6448
04:38:14,939 --> 04:38:15,939
about the protocols in more depth later
6449
04:38:16,740 --> 04:38:17,740
too when we talk about what tcpip is but
6450
04:38:19,740 --> 04:38:20,740
I want to start talking about these now
6451
04:38:21,359 --> 04:38:22,359
since a port is really the end point
6452
04:38:24,840 --> 04:38:25,840
logically of a connection
6453
04:38:27,061 --> 04:38:28,061
so we're going to start by talking about
6454
04:38:29,219 --> 04:38:30,219
what a port is in a little more detail
6455
04:38:31,260 --> 04:38:32,260
and outline the different port ranges
6456
04:38:33,719 --> 04:38:34,719
there are three of them well-known ports
6457
04:38:36,080 --> 04:38:37,080
registered ports and then the last range
6458
04:38:38,820 --> 04:38:39,820
which is
6459
04:38:40,379 --> 04:38:41,379
um
6460
04:38:41,539 --> 04:38:42,539
experimental sort of ports and private
6461
04:38:44,219 --> 04:38:45,219
ports so we're going to outline the most
6462
04:38:47,039 --> 04:38:48,039
common well-known default ports and the
6463
04:38:50,699 --> 04:38:51,699
protocols that go along with them I'm
6464
04:38:52,500 --> 04:38:53,500
actually going to give you a huge list
6465
04:38:54,000 --> 04:38:55,000
of all the protocols you need to know
6466
04:38:55,561 --> 04:38:56,561
and we're going to talk about some of
6467
04:38:57,061 --> 04:38:58,061
those in depth in this module some in
6468
04:38:59,100 --> 04:39:00,100
the next module and then some later on
6469
04:39:01,439 --> 04:39:02,439
in the course but I'm going to get them
6470
04:39:03,061 --> 04:39:04,061
all out onto a a chart for you right now
6471
04:39:06,299 --> 04:39:07,299
finally I wanted to find and describe
6472
04:39:08,641 --> 04:39:09,641
the common ports and protocols dealing
6473
04:39:11,100 --> 04:39:12,100
with FTP or the file transfer protocol
6474
04:39:14,480 --> 04:39:15,480
ntp or the network time protocol
6475
04:39:17,420 --> 04:39:18,420
SMTP the simple mail transfer protocol
6476
04:39:20,600 --> 04:39:21,600
POP3 or the post office protocol the uh
6477
04:39:25,080 --> 04:39:26,080
used to receive email as opposed to SMTP
6478
04:39:28,561 --> 04:39:29,561
which is used to send email IMAP which
6479
04:39:31,859 --> 04:39:32,859
is also used for receiving or accessing
6480
04:39:35,520 --> 04:39:36,520
email which stands for the internet
6481
04:39:37,141 --> 04:39:38,141
message access protocol
6482
04:39:40,580 --> 04:39:41,580
nntp or the network news transfer
6483
04:39:44,820 --> 04:39:45,820
protocol uh something you may have used
6484
04:39:47,640 --> 04:39:48,640
if you've ever used RSS feeds HTTP or
6485
04:39:51,718 --> 04:39:52,718
the hypertext transfer protocol and
6486
04:39:54,540 --> 04:39:55,540
https which is the secure version these
6487
04:39:57,840 --> 04:39:58,840
are what allow you to browse on the
6488
04:39:59,760 --> 04:40:00,760
internet and finally we'll talk about
6489
04:40:01,378 --> 04:40:02,378
RDP or the remote desktop protocol which
6490
04:40:05,760 --> 04:40:06,760
allows you to remote in to a Microsoft
6491
04:40:08,700 --> 04:40:09,700
computer all right so let's talk about
6492
04:40:11,760 --> 04:40:12,760
these in more depth first off we have to
6493
04:40:15,298 --> 04:40:16,298
define a port in computers and
6494
04:40:18,120 --> 04:40:19,120
networking a port is a process specific
6495
04:40:21,420 --> 04:40:22,420
or application specific designation that
6496
04:40:25,020 --> 04:40:26,020
serves as a communication endpoint in
6497
04:40:27,660 --> 04:40:28,660
the computer's operating system meaning
6498
04:40:30,060 --> 04:40:31,060
where the communication logically ends
6499
04:40:32,820 --> 04:40:33,820
once it reaches the user the port
6500
04:40:35,100 --> 04:40:36,100
identifies specific processes and
6501
04:40:38,280 --> 04:40:39,280
applications and denotes the path that
6502
04:40:42,360 --> 04:40:43,360
they take through the network
6503
04:40:44,160 --> 04:40:45,160
now the internet assigned numbers
6504
04:40:46,378 --> 04:40:47,378
Authority or the i a n a
6505
04:40:52,500 --> 04:40:53,500
is the governing entity that regulates
6506
04:40:54,958 --> 04:40:55,958
all of these Port assignments and also
6507
04:40:57,958 --> 04:40:58,958
defines the numbers or the numbering
6508
04:40:59,940 --> 04:41:00,940
convention that they're given now these
6509
04:41:02,100 --> 04:41:03,100
ports range from 1 to over 65 000. Port
6510
04:41:07,020 --> 04:41:08,020
0 is reserved and it's never used so
6511
04:41:09,540 --> 04:41:10,540
don't really worry about that now within
6512
04:41:13,020 --> 04:41:14,020
this range we actually have three
6513
04:41:14,878 --> 04:41:15,878
different subsets of ranges and as
6514
04:41:17,580 --> 04:41:18,580
administrators knowing the common ports
6515
04:41:19,920 --> 04:41:20,920
is crucial to managing a successful
6516
04:41:22,560 --> 04:41:23,560
Network
6517
04:41:23,458 --> 04:41:24,458
the common ports are some of the
6518
04:41:25,440 --> 04:41:26,440
guaranteed few questions that I I know
6519
04:41:28,500 --> 04:41:29,500
you're going to have on the network plus
6520
04:41:29,820 --> 04:41:30,820
examination and nearly every other
6521
04:41:32,218 --> 04:41:33,218
network examination as well so covering
6522
04:41:34,680 --> 04:41:35,680
these and committing these to memory is
6523
04:41:36,780 --> 04:41:37,780
of the utmost importance now within that
6524
04:41:39,000 --> 04:41:40,000
range from 1 to over 65 000 there are
6525
04:41:42,240 --> 04:41:43,240
three recognized blocks or subsets of
6526
04:41:45,000 --> 04:41:46,000
ports the first block is considered the
6527
04:41:47,760 --> 04:41:48,760
well-known ports these ports range from
6528
04:41:51,000 --> 04:41:52,000
one to one thousand twenty three this is
6529
04:41:53,580 --> 04:41:54,580
where we're mostly going to look at
6530
04:41:55,020 --> 04:41:56,020
ports uh when we look at them in just a
6531
04:41:57,240 --> 04:41:58,240
minute
6532
04:41:57,958 --> 04:41:58,958
these are used by Common services and
6533
04:42:00,900 --> 04:42:01,900
are pretty much known by just about
6534
04:42:02,940 --> 04:42:03,940
everyone in the field
6535
04:42:04,560 --> 04:42:05,560
now the next range of ports is called
6536
04:42:06,360 --> 04:42:07,360
the registered ports range these span
6537
04:42:08,700 --> 04:42:09,700
from 1024 to 49
6538
04:42:11,780 --> 04:42:12,780
151. these are reserved by applications
6539
04:42:15,240 --> 04:42:16,240
and programs that register with the Iana
6540
04:42:19,160 --> 04:42:20,160
an example might be for instance
6541
04:42:22,740 --> 04:42:23,740
Skype
6542
04:42:25,500 --> 04:42:26,500
which registers and utilizes Port I
6543
04:42:28,620 --> 04:42:29,620
think
6544
04:42:30,138 --> 04:42:31,138
23399 as its default protocol don't
6545
04:42:34,200 --> 04:42:35,200
worry about that but if you're curious
6546
04:42:35,940 --> 04:42:36,940
for your firewall's sake this is the
6547
04:42:38,100 --> 04:42:39,100
port I believe Skype uses
6548
04:42:40,080 --> 04:42:41,080
finally we have the dynamic or the
6549
04:42:42,958 --> 04:42:43,958
private Port range this is everything
6550
04:42:45,240 --> 04:42:46,240
else 49 152 to 65 535. these are used by
6551
04:42:51,120 --> 04:42:52,120
unregistered services in uh test
6552
04:42:54,240 --> 04:42:55,240
settings and also for temporary
6553
04:42:56,160 --> 04:42:57,160
connections you can't register these
6554
04:42:58,200 --> 04:42:59,200
with the Ina they're just left open for
6555
04:43:00,958 --> 04:43:01,958
anyone to use for whatever purposes you
6556
04:43:03,360 --> 04:43:04,360
may need them
6557
04:43:04,440 --> 04:43:05,440
so now let's talk about the well-known
6558
04:43:06,718 --> 04:43:07,718
default ports you need to know for the
6559
04:43:08,520 --> 04:43:09,520
exam this chart is really what you
6560
04:43:11,040 --> 04:43:12,040
should commit to memory since uh and
6561
04:43:13,560 --> 04:43:14,560
when you get to the test you want to be
6562
04:43:15,600 --> 04:43:16,600
able to basically recreate this chart
6563
04:43:18,240 --> 04:43:19,240
before you sit down and take the test
6564
04:43:19,920 --> 04:43:20,920
you'll be able to do this in what's
6565
04:43:21,360 --> 04:43:22,360
called a brain dump sheet so let's talk
6566
04:43:24,240 --> 04:43:25,240
about the first portion of these ports
6567
04:43:25,680 --> 04:43:26,680
we need to know the first is Port 7.
6568
04:43:28,560 --> 04:43:29,560
this is for the icmp echo request or
6569
04:43:31,980 --> 04:43:32,980
ping if you've ever pinged something
6570
04:43:34,080 --> 04:43:35,080
from the command line this is what we're
6571
04:43:35,940 --> 04:43:36,940
talking about we'll talk more about this
6572
04:43:38,040 --> 04:43:39,040
a little bit later
6573
04:43:39,480 --> 04:43:40,480
next we have Port 20 and 21. these are
6574
04:43:43,920 --> 04:43:44,920
for the FTP or file transfer protocol
6575
04:43:46,620 --> 04:43:47,620
which allows you to transfer files over
6576
04:43:49,680 --> 04:43:50,680
a network we'll talk more about this in
6577
04:43:51,958 --> 04:43:52,958
just a minute
6578
04:43:53,160 --> 04:43:54,160
Port 22 is for the secure shell or SSH
6579
04:43:56,700 --> 04:43:57,700
and Port 23 is for telnet both of those
6580
04:44:00,298 --> 04:44:01,298
we're going to discuss later on in a
6581
04:44:02,218 --> 04:44:03,218
different module but they're sort of
6582
04:44:04,020 --> 04:44:05,020
allowing you to remote in and control a
6583
04:44:06,600 --> 04:44:07,600
remote computer albeit not from a
6584
04:44:09,240 --> 04:44:10,240
graphical standpoint
6585
04:44:10,920 --> 04:44:11,920
Port 25 is the SMTP or simple mail
6586
04:44:14,580 --> 04:44:15,580
transfer protocol which allows you to
6587
04:44:16,940 --> 04:44:17,940
receive email and DNS or the domain name
6588
04:44:21,540 --> 04:44:22,540
service which uses Port 53 is what
6589
04:44:24,660 --> 04:44:25,660
allows you to transmit or to translate
6590
04:44:27,798 --> 04:44:28,798
say google.com into its IP address when
6591
04:44:31,860 --> 04:44:32,860
you're browsing out on the internet this
6592
04:44:33,718 --> 04:44:34,718
is a really important protocol and we'll
6593
04:44:35,700 --> 04:44:36,700
talk more about it later along with the
6594
04:44:37,980 --> 04:44:38,980
the DNS sort of server
6595
04:44:40,560 --> 04:44:41,560
Port 67 and 68 are for what are called
6596
04:44:45,500 --> 04:44:46,500
DHCP and boot P or the bootstrap service
6597
04:44:49,200 --> 04:44:50,200
for servers and client respectively
6598
04:44:51,840 --> 04:44:52,840
one for uh servers and one for clients
6599
04:44:56,580 --> 04:44:57,580
as we can see
6600
04:44:58,020 --> 04:44:59,020
right here
6601
04:45:00,180 --> 04:45:01,180
we're going to Define and describe those
6602
04:45:01,798 --> 04:45:02,798
in more detail in the next lesson
6603
04:45:04,440 --> 04:45:05,440
now Port 69 is the trivial file transfer
6604
04:45:08,100 --> 04:45:09,100
protocol this is related to the file
6605
04:45:10,860 --> 04:45:11,860
transfer protocol we mentioned up here
6606
04:45:13,020 --> 04:45:14,020
but it is Trivial meaning that it is not
6607
04:45:16,620 --> 04:45:17,620
a connection oriented and doesn't really
6608
04:45:19,920 --> 04:45:20,920
guarantee that the file has been
6609
04:45:22,020 --> 04:45:23,020
transferred
6610
04:45:23,340 --> 04:45:24,340
Port 123 is the network time protocol
6611
04:45:27,060 --> 04:45:28,060
which keeps the clock on a network or on
6612
04:45:30,240 --> 04:45:31,240
computers on the network up to sync a
6613
04:45:32,280 --> 04:45:33,280
great way to remember this is that time
6614
04:45:33,840 --> 04:45:34,840
is always counting one two three
6615
04:45:38,040 --> 04:45:39,040
uh Port 110 is for the pop three or the
6616
04:45:41,458 --> 04:45:42,458
post office protocol which is how many
6617
04:45:43,560 --> 04:45:44,560
of us download our email onto our local
6618
04:45:46,320 --> 04:45:47,320
device
6619
04:45:48,120 --> 04:45:49,120
and then Port 137 is the net bios naming
6620
04:45:51,958 --> 04:45:52,958
service this is similar to DNS but is
6621
04:45:56,100 --> 04:45:57,100
specific to Windows operating systems or
6622
04:45:59,160 --> 04:46:00,160
Microsoft operating systems
6623
04:46:01,500 --> 04:46:02,500
related to pop 3 is Port 143 which is
6624
04:46:05,400 --> 04:46:06,400
IMAP the internet message access
6625
04:46:07,378 --> 04:46:08,378
protocol this is another way of
6626
04:46:09,660 --> 04:46:10,660
accessing and managing your email let's
6627
04:46:13,560 --> 04:46:14,560
continue taking a look at a few more
6628
04:46:15,600 --> 04:46:16,600
protocols that are equally important
6629
04:46:19,680 --> 04:46:20,680
the first is the simple Network
6630
04:46:21,480 --> 04:46:22,480
management protocol which allows you to
6631
04:46:23,878 --> 04:46:24,878
manage devices on network Say by getting
6632
04:46:27,000 --> 04:46:28,000
error messages from your printer or from
6633
04:46:29,520 --> 04:46:30,520
a router this uses Port 161. we'll
6634
04:46:32,700 --> 04:46:33,700
discuss this a lot more in detail later
6635
04:46:34,620 --> 04:46:35,620
as well
6636
04:46:35,700 --> 04:46:36,700
port 389 is the lightweight directory
6637
04:46:39,420 --> 04:46:40,420
access protocol this is what allows a
6638
04:46:42,240 --> 04:46:43,240
Windows server to have usernames and
6639
04:46:45,718 --> 04:46:46,718
passwords
6640
04:46:48,000 --> 04:46:49,000
Port 443 is https or the hypertext
6641
04:46:52,560 --> 04:46:53,560
transfer protocol over secure socket
6642
04:46:55,680 --> 04:46:56,680
layer notice the S here this is what
6643
04:46:58,980 --> 04:46:59,980
allows us to browse the internet but
6644
04:47:02,040 --> 04:47:03,040
securely
6645
04:47:03,600 --> 04:47:04,600
we also have Port 500 which is ipsec
6646
04:47:07,798 --> 04:47:08,798
this one also has another name which
6647
04:47:09,840 --> 04:47:10,840
stands for Internet Security Association
6648
04:47:11,940 --> 04:47:12,940
and Key Management protocol basically
6649
04:47:14,638 --> 04:47:15,638
ipsec or IP security is what allows us
6650
04:47:17,940 --> 04:47:18,940
to have secure connections over IP
6651
04:47:22,320 --> 04:47:23,320
finally we're going into RDP or the
6652
04:47:25,320 --> 04:47:26,320
remote desktop protocol which allows us
6653
04:47:27,480 --> 04:47:28,480
to remotely access a computer Windows
6654
04:47:30,958 --> 04:47:31,958
based specifically
6655
04:47:32,878 --> 04:47:33,878
Port 119 or the network news transfer
6656
04:47:37,020 --> 04:47:38,020
protocol which is not only used with
6657
04:47:39,180 --> 04:47:40,180
Usenet a sort of Message Board that's
6658
04:47:41,580 --> 04:47:42,580
been around for a very long time but
6659
04:47:43,620 --> 04:47:44,620
also RSS feeds which you might be more
6660
04:47:45,780 --> 04:47:46,780
familiar with and finally Port 80 is
6661
04:47:48,958 --> 04:47:49,958
HTTP or hypertext transfer protocol the
6662
04:47:53,218 --> 04:47:54,218
other thing to know about HTTP is it has
6663
04:47:55,378 --> 04:47:56,378
an alternate Port of 8080 so you might
6664
04:47:58,320 --> 04:47:59,320
see either one of these on there
6665
04:48:01,020 --> 04:48:02,020
all right now I know that was a lot of
6666
04:48:03,120 --> 04:48:04,120
information I just threw out there but
6667
04:48:05,160 --> 04:48:06,160
we're going to cover these all in a
6668
04:48:06,600 --> 04:48:07,600
little more depth as we go through here
6669
04:48:08,100 --> 04:48:09,100
and I just wanted to lay them out in a
6670
04:48:10,680 --> 04:48:11,680
very simple
6671
04:48:11,900 --> 04:48:12,900
chart-based way so that you could commit
6672
04:48:14,458 --> 04:48:15,458
them to Memory
6673
04:48:15,780 --> 04:48:16,780
now let's talk about these in a little
6674
04:48:17,520 --> 04:48:18,520
more depth understand how they function
6675
04:48:19,680 --> 04:48:20,680
and why first up is the file transfer
6676
04:48:23,400 --> 04:48:24,400
protocol or FTP this protocol enables
6677
04:48:27,480 --> 04:48:28,480
the transfer of files between a user's
6678
04:48:30,600 --> 04:48:31,600
computer and a remote host
6679
04:48:33,000 --> 04:48:34,000
using the file transfer protocol or FTP
6680
04:48:36,060 --> 04:48:37,060
you can view change search for upload or
6681
04:48:41,218 --> 04:48:42,218
download files now where while this
6682
04:48:43,560 --> 04:48:44,560
sounds really great as a way to access
6683
04:48:45,958 --> 04:48:46,958
files remotely it has a few
6684
04:48:48,240 --> 04:48:49,240
considerations that need to be kept in
6685
04:48:49,980 --> 04:48:50,980
mind the first is that FTP by itself is
6686
04:48:53,878 --> 04:48:54,878
very unsecure and an FTP Daemon which is
6687
04:48:59,458 --> 04:49:00,458
a Unix term for a service
6688
04:49:03,900 --> 04:49:04,900
has to be running on the remote computer
6689
04:49:07,080 --> 04:49:08,080
in order for this to work you might also
6690
04:49:10,080 --> 04:49:11,080
have to have an FTP utility or client on
6691
04:49:13,440 --> 04:49:14,440
the client computer in order for you to
6692
04:49:16,200 --> 04:49:17,200
have this protocol operate effectively
6693
04:49:18,480 --> 04:49:19,480
and for you to be able to use it now
6694
04:49:21,420 --> 04:49:22,420
trivial FTP is the simple version of FTP
6695
04:49:25,138 --> 04:49:26,138
and does not support error correction
6696
04:49:27,240 --> 04:49:28,240
and doesn't guarantee that a file is
6697
04:49:29,638 --> 04:49:30,638
actually getting where it needs to it's
6698
04:49:31,560 --> 04:49:32,560
typically not really used in many actual
6699
04:49:34,378 --> 04:49:35,378
file transfer settings now just as I
6700
04:49:37,020 --> 04:49:38,020
just mentioned you might need a client
6701
04:49:38,840 --> 04:49:39,840
FTP uh software on your computer
6702
04:49:42,900 --> 04:49:43,900
generally speaking there is a command
6703
04:49:44,940 --> 04:49:45,940
line prompt that you can use
6704
04:49:47,218 --> 04:49:48,218
it goes like this FTP
6705
04:49:49,860 --> 04:49:50,860
space the fully qualified domain name
6706
04:49:53,100 --> 04:49:54,100
for instance google.com FTP which I
6707
04:49:56,820 --> 04:49:57,820
don't think is the actual one or the IP
6708
04:49:59,638 --> 04:50:00,638
address of the remote host you only need
6709
04:50:02,400 --> 04:50:03,400
one or the other if you provide the IP
6710
04:50:04,920 --> 04:50:05,920
address you're sort of using the direct
6711
04:50:06,360 --> 04:50:07,360
route if you're using What's called the
6712
04:50:08,520 --> 04:50:09,520
fully qualified domain name which we'll
6713
04:50:10,798 --> 04:50:11,798
talk about a little bit later then you
6714
04:50:13,320 --> 04:50:14,320
allow something called DNS or the domain
6715
04:50:15,718 --> 04:50:16,718
name service
6716
04:50:17,458 --> 04:50:18,458
to do the translation into uh a IP
6717
04:50:22,440 --> 04:50:23,440
address for you remember again that FTP
6718
04:50:25,920 --> 04:50:26,920
uses ports 20
6719
04:50:28,320 --> 04:50:29,320
and 21 by default
6720
04:50:33,540 --> 04:50:34,540
next is the simple mail transfer
6721
04:50:36,298 --> 04:50:37,298
protocol or SMTP
6722
04:50:39,840 --> 04:50:40,840
this is used to manage the formatting
6723
04:50:42,360 --> 04:50:43,360
and sending of email messages
6724
04:50:45,620 --> 04:50:46,620
specifically we're looking here at
6725
04:50:47,700 --> 04:50:48,700
outgoing email
6726
04:50:49,680 --> 04:50:50,680
using a method called store and forward
6727
04:50:52,638 --> 04:50:53,638
SMTP can hold on to a message until the
6728
04:50:56,638 --> 04:50:57,638
recipient comes online this is why it's
6729
04:50:59,638 --> 04:51:00,638
used over unreliable wide area network
6730
04:51:02,820 --> 04:51:03,820
links once the device comes online it
6731
04:51:06,600 --> 04:51:07,600
hands the message off to the server the
6732
04:51:09,120 --> 04:51:10,120
SMTP message has several things
6733
04:51:11,600 --> 04:51:12,600
including a header
6734
04:51:14,218 --> 04:51:15,218
that contains Source information as to
6735
04:51:17,520 --> 04:51:18,520
where it's coming from and it also has
6736
04:51:21,500 --> 04:51:22,500
destination information as to where it's
6737
04:51:24,360 --> 04:51:25,360
going
6738
04:51:26,218 --> 04:51:27,218
of course there's also content
6739
04:51:28,200 --> 04:51:29,200
information which is inside of the
6740
04:51:30,718 --> 04:51:31,718
packet
6741
04:51:31,798 --> 04:51:32,798
the default port for SMTP is Port 25
6742
04:51:35,840 --> 04:51:36,840
although sometimes you might see it use
6743
04:51:38,580 --> 04:51:39,580
port 587 which is uh by relay I wouldn't
6744
04:51:42,420 --> 04:51:43,420
worry too much about that one for the
6745
04:51:44,340 --> 04:51:45,340
exam but just keep in mind Port 25. now
6746
04:51:48,060 --> 04:51:49,060
like SMTP POP3 is a protocol that's used
6747
04:51:53,340 --> 04:51:54,340
in handling email messages and POP3
6748
04:51:56,580 --> 04:51:57,580
stands for the Post Office protocol
6749
04:51:58,638 --> 04:51:59,638
version 3 which is the commonly used
6750
04:52:01,680 --> 04:52:02,680
version now
6751
04:52:03,060 --> 04:52:04,060
specifically POP3 is used for the
6752
04:52:05,580 --> 04:52:06,580
receipt of email or incoming email and
6753
04:52:09,298 --> 04:52:10,298
it does this by retrieving email
6754
04:52:11,638 --> 04:52:12,638
messages from a mail server it's
6755
04:52:14,400 --> 04:52:15,400
designed to pull the messages down and
6756
04:52:16,980 --> 04:52:17,980
then once it does that the server
6757
04:52:19,080 --> 04:52:20,080
deletes the message on the server Source
6758
04:52:23,280 --> 04:52:24,280
by default although you can change that
6759
04:52:25,980 --> 04:52:26,980
if an administrator wants to this makes
6760
04:52:28,860 --> 04:52:29,860
POP3 not as desirable and weaker than
6761
04:52:33,060 --> 04:52:34,060
most some other mail protocols
6762
04:52:34,620 --> 04:52:35,620
specifically IMAP which we're going to
6763
04:52:36,180 --> 04:52:37,180
see because it puts all of the brunt of
6764
04:52:40,200 --> 04:52:41,200
the responsibility onto the client for
6765
04:52:42,780 --> 04:52:43,780
storing and managing emails and deletes
6766
04:52:45,060 --> 04:52:46,060
all the emails at the source so if
6767
04:52:47,458 --> 04:52:48,458
something happens to your computer and
6768
04:52:48,958 --> 04:52:49,958
you don't have a backup you're in big
6769
04:52:50,878 --> 04:52:51,878
trouble
6770
04:52:51,718 --> 04:52:52,718
the default port for POP3 as we
6771
04:52:53,820 --> 04:52:54,820
mentioned is Port 110. so remember Port
6772
04:52:57,240 --> 04:52:58,240
110 is POP3 and Port 25 is SMTP now IMAP
6773
04:53:02,760 --> 04:53:03,760
4 usually just called IMAP is the
6774
04:53:06,060 --> 04:53:07,060
internet message access protocol and
6775
04:53:08,820 --> 04:53:09,820
it's similar to POP3 in that it's also
6776
04:53:10,740 --> 04:53:11,740
utilized for incoming mail or mail
6777
04:53:13,378 --> 04:53:14,378
retrieval but in nearly every way IMAP
6778
04:53:16,798 --> 04:53:17,798
surpasses POP3 it's a much more powerful
6779
04:53:20,100 --> 04:53:21,100
protocol because it offers more benefits
6780
04:53:23,040 --> 04:53:24,040
like easier mailbox management more
6781
04:53:26,400 --> 04:53:27,400
granular search capabilities and so on
6782
04:53:28,798 --> 04:53:29,798
with IMAP users can search through
6783
04:53:31,680 --> 04:53:32,680
messages by keywords and choose which
6784
04:53:34,080 --> 04:53:35,080
messages they want to download they can
6785
04:53:36,120 --> 04:53:37,120
also leave IMAP messages on the server
6786
04:53:38,700 --> 04:53:39,700
and still work with them as though
6787
04:53:40,980 --> 04:53:41,980
they're on the local computer
6788
04:53:42,958 --> 04:53:43,958
so it seems that the two are synced
6789
04:53:47,520 --> 04:53:48,520
together perfectly the server and the
6790
04:53:49,680 --> 04:53:50,680
client
6791
04:53:50,638 --> 04:53:51,638
also an email message with say a
6792
04:53:52,798 --> 04:53:53,798
multimedia file can be partially
6793
04:53:55,020 --> 04:53:56,020
downloaded to save bandwidth
6794
04:53:58,080 --> 04:53:59,080
now the main benefit here is we're going
6795
04:54:00,600 --> 04:54:01,600
to use this instead of first say a
6796
04:54:02,160 --> 04:54:03,160
computer let's say I have a smartphone
6797
04:54:04,080 --> 04:54:05,080
and a computer now it's going to make
6798
04:54:07,260 --> 04:54:08,260
sure because the source is all stored at
6799
04:54:10,320 --> 04:54:11,320
the server
6800
04:54:11,700 --> 04:54:12,700
that if I delete something say on my
6801
04:54:14,638 --> 04:54:15,638
computer that syncs up to the server and
6802
04:54:18,000 --> 04:54:19,000
then the server will have that sync with
6803
04:54:19,320 --> 04:54:20,320
this my smartphone so all of these are
6804
04:54:21,718 --> 04:54:22,718
in perfect synchronization this is why
6805
04:54:24,240 --> 04:54:25,240
it's much stronger than POP3 which
6806
04:54:26,940 --> 04:54:27,940
simply downloads the email onto your
6807
04:54:29,280 --> 04:54:30,280
client device
6808
04:54:30,660 --> 04:54:31,660
by default IMAP uses Port 143 which is
6809
04:54:35,400 --> 04:54:36,400
different from IMAP
6810
04:54:36,900 --> 04:54:37,900
POP3 rather which uses 110.
6811
04:54:41,040 --> 04:54:42,040
now ntp or the network time protocol is
6812
04:54:45,000 --> 04:54:46,000
an Internet Protocol that synchronizes
6813
04:54:47,040 --> 04:54:48,040
system Clocks by exchanging time signals
6814
04:54:50,580 --> 04:54:51,580
between a client and a Master Clock
6815
04:54:52,860 --> 04:54:53,860
server the computers are constantly
6816
04:54:55,500 --> 04:54:56,500
running this in the background and this
6817
04:54:57,540 --> 04:54:58,540
protocol will send requests to the
6818
04:55:00,060 --> 04:55:01,060
server to obtain accurate time updates
6819
04:55:03,120 --> 04:55:04,120
up to the millisecond this time is
6820
04:55:06,298 --> 04:55:07,298
checked against the U.S Naval
6821
04:55:08,180 --> 04:55:09,180
Observatory Master Clock or atomic clock
6822
04:55:11,458 --> 04:55:12,458
so the timestamps on the received
6823
04:55:14,340 --> 04:55:15,340
updates are verified with this Master
6824
04:55:17,820 --> 04:55:18,820
Clock server which is again that US
6825
04:55:20,580 --> 04:55:21,580
Naval server
6826
04:55:23,458 --> 04:55:24,458
and the computers then update their time
6827
04:55:26,160 --> 04:55:27,160
accordingly
6828
04:55:27,600 --> 04:55:28,600
the port this uses is Port 123 which is
6829
04:55:30,958 --> 04:55:31,958
as easy to remember as time
6830
04:55:34,260 --> 04:55:35,260
keeps moving up one two three
6831
04:55:38,820 --> 04:55:39,820
now if we add an additional n to the
6832
04:55:41,100 --> 04:55:42,100
previous one we get What's called the
6833
04:55:43,020 --> 04:55:44,020
network news transfer protocol
6834
04:55:46,138 --> 04:55:47,138
this is very different from the network
6835
04:55:47,878 --> 04:55:48,878
time protocol it's used for the
6836
04:55:50,340 --> 04:55:51,340
retrieval and posting of news group
6837
04:55:53,040 --> 04:55:54,040
messages or bulletin messages to the
6838
04:55:56,760 --> 04:55:57,760
Usenet which is a worldwide bulletin
6839
04:55:59,040 --> 04:56:00,040
board that's been around since the 1980s
6840
04:56:01,920 --> 04:56:02,920
really since the internet was in its
6841
04:56:04,500 --> 04:56:05,500
nascent stages the network news transfer
6842
04:56:07,560 --> 04:56:08,560
protocol is also the protocol that RSS
6843
04:56:11,100 --> 04:56:12,100
feeds are based on this stands for
6844
04:56:13,440 --> 04:56:14,440
really
6845
04:56:15,240 --> 04:56:16,240
simple
6846
04:56:17,638 --> 04:56:18,638
syndication
6847
04:56:23,100 --> 04:56:24,100
basically this is where a user can
6848
04:56:25,740 --> 04:56:26,740
subscribe to an article web page blog or
6849
04:56:29,580 --> 04:56:30,580
something similar that uses this
6850
04:56:31,138 --> 04:56:32,138
protocol and when an update is made to
6851
04:56:33,840 --> 04:56:34,840
that page or to that article the
6852
04:56:36,060 --> 04:56:37,060
subscriber is updated
6853
04:56:37,798 --> 04:56:38,798
so in this way you can get updated
6854
04:56:41,400 --> 04:56:42,400
articles from your favorite web page
6855
04:56:43,200 --> 04:56:44,200
just like you would new
6856
04:56:45,840 --> 04:56:46,840
emails with nntp however only postings
6857
04:56:51,298 --> 04:56:52,298
and articles that are new or updated are
6858
04:56:53,638 --> 04:56:54,638
submitted and retrieved from the server
6859
04:56:55,440 --> 04:56:56,440
slightly different from RSS but RSS is
6860
04:56:58,740 --> 04:56:59,740
based on nntp the default port for this
6861
04:57:02,280 --> 04:57:03,280
is port 119.
6862
04:57:05,160 --> 04:57:06,160
so we're covering a lot of different
6863
04:57:06,840 --> 04:57:07,840
numbers here it's really important
6864
04:57:08,638 --> 04:57:09,638
perhaps even more than memorizing uh
6865
04:57:11,760 --> 04:57:12,760
specifically what each protocol does
6866
04:57:14,218 --> 04:57:15,218
that you definitely memorize which Port
6867
04:57:16,620 --> 04:57:17,620
it's a part of if you can memorize by
6868
04:57:19,080 --> 04:57:20,080
the way the number
6869
04:57:20,760 --> 04:57:21,760
and what the acronym means you should be
6870
04:57:23,280 --> 04:57:24,280
fine now a protocol you use every day
6871
04:57:25,860 --> 04:57:26,860
even if you don't realize it is HTTP or
6872
04:57:29,218 --> 04:57:30,218
the hypertext transfer protocol this is
6873
04:57:32,520 --> 04:57:33,520
used to view unsecure web pages and
6874
04:57:35,580 --> 04:57:36,580
allows users to connect to and
6875
04:57:38,218 --> 04:57:39,218
communicate with web servers although
6876
04:57:41,040 --> 04:57:42,040
HTTP is going to define the transmission
6877
04:57:44,540 --> 04:57:45,540
and the format of messages and the
6878
04:57:47,520 --> 04:57:48,520
actions taken by web servers when users
6879
04:57:50,160 --> 04:57:51,160
interact with it HTTP is what we call a
6880
04:57:54,298 --> 04:57:55,298
stateless protocol meaning that it may
6881
04:57:57,780 --> 04:57:58,780
be difficult to get a lot of intelligent
6882
04:58:01,020 --> 04:58:02,020
interactive responses to the information
6883
04:58:03,600 --> 04:58:04,600
if you remember ever making very basic
6884
04:58:07,020 --> 04:58:08,020
web pages using HTML or the hypertext
6885
04:58:11,580 --> 04:58:12,580
markup language the language that HTTP
6886
04:58:15,540 --> 04:58:16,540
is reading then you probably know this
6887
04:58:17,580 --> 04:58:18,580
so if you want more interactive web page
6888
04:58:20,700 --> 04:58:21,700
Pages or interaction with web pages then
6889
04:58:23,700 --> 04:58:24,700
you're going to use different add-ons
6890
04:58:25,500 --> 04:58:26,500
such as ActiveX that you might have
6891
04:58:27,958 --> 04:58:28,958
heard of
6892
04:58:29,900 --> 04:58:30,900
HTTP defaults Port is Port 80 and a
6893
04:58:34,080 --> 04:58:35,080
common alternate port for it is Port
6894
04:58:36,500 --> 04:58:37,500
8080. now similar to http is https
6895
04:58:41,600 --> 04:58:42,600
or hypertext transfer protocol over SSL
6896
04:58:46,200 --> 04:58:47,200
which is the secure socket layer this is
6897
04:58:50,878 --> 04:58:51,878
a secure version of HTTP so if you ever
6898
04:58:54,240 --> 04:58:55,240
see an s on the end of just about any
6899
04:58:55,920 --> 04:58:56,920
protocol you can bet that that has to do
6900
04:58:58,560 --> 04:58:59,560
with this being secure and it creates
6901
04:59:01,260 --> 04:59:02,260
secure connections between your browser
6902
04:59:03,958 --> 04:59:04,958
and the web server it does this using
6903
04:59:07,580 --> 04:59:08,580
SSL or the secure
6904
04:59:11,580 --> 04:59:12,580
sockets
6905
04:59:14,218 --> 04:59:15,218
layer
6906
04:59:16,080 --> 04:59:17,080
we're going to discuss the secure
6907
04:59:17,940 --> 04:59:18,940
sockets layer when we discuss encryption
6908
04:59:20,400 --> 04:59:21,400
more detail in a future lesson
6909
04:59:23,160 --> 04:59:24,160
now most web pages support https and
6910
04:59:27,600 --> 04:59:28,600
it's recommended that you use it over
6911
04:59:29,458 --> 04:59:30,458
HTTP almost every time you're able to
6912
04:59:31,920 --> 04:59:32,920
the way you do this is simply by using
6913
04:59:35,580 --> 04:59:36,580
instead of HTTP colon slash slash
6914
04:59:39,200 --> 04:59:40,200
facebook.com just put an S in front
6915
04:59:43,320 --> 04:59:44,320
yes Facebook supports this as do other
6916
04:59:45,900 --> 04:59:46,900
social media sites and even email and
6917
04:59:48,718 --> 04:59:49,718
even Google supports https why would you
6918
04:59:51,360 --> 04:59:52,360
want to do this well say someone is
6919
04:59:53,040 --> 04:59:54,040
browsing and or listening in to your
6920
04:59:56,700 --> 04:59:57,700
Google searches that might be
6921
04:59:58,320 --> 04:59:59,320
information you don't want someone else
6922
04:59:59,700 --> 05:00:00,700
to know
6923
05:00:00,718 --> 05:00:01,718
just as a recommendation absolutely
6924
05:00:03,240 --> 05:00:04,240
anytime you visit any website but
6925
05:00:05,100 --> 05:00:06,100
especially Financial uh institutions
6926
05:00:08,400 --> 05:00:09,400
such as your bank or your credit union
6927
05:00:11,218 --> 05:00:12,218
you want to ensure that in the bar it
6928
05:00:13,500 --> 05:00:14,500
says https if it's not then opening
6929
05:00:17,400 --> 05:00:18,400
anything in this including typing in
6930
05:00:19,138 --> 05:00:20,138
your bank password could be really
6931
05:00:20,940 --> 05:00:21,940
serious
6932
05:00:22,020 --> 05:00:23,020
the same goes for anything when we're
6933
05:00:23,760 --> 05:00:24,760
dealing with credit cards for instance
6934
05:00:25,740 --> 05:00:26,740
buying something make sure that https
6935
05:00:28,280 --> 05:00:29,280
appears in the bar or in your url bar at
6936
05:00:31,920 --> 05:00:32,920
the top as we've mentioned before too
6937
05:00:34,020 --> 05:00:35,020
the default Port is Port 443
6938
05:00:39,000 --> 05:00:40,000
now the last port I want to discuss is
6939
05:00:41,458 --> 05:00:42,458
RDP or the remote desktop protocol RDP
6940
05:00:45,600 --> 05:00:46,600
servers are built into the Microsoft
6941
05:00:48,000 --> 05:00:49,000
operating system such as Windows by
6942
05:00:51,780 --> 05:00:52,780
default and it provides users with a
6943
05:00:54,600 --> 05:00:55,600
graphical user interface or a GUI
6944
05:00:59,520 --> 05:01:00,520
to another computer over a network
6945
05:01:02,100 --> 05:01:03,100
connection
6946
05:01:03,120 --> 05:01:04,120
so this protocol allows users to
6947
05:01:05,458 --> 05:01:06,458
remotely manage administer and access
6948
05:01:09,298 --> 05:01:10,298
network resources from another physical
6949
05:01:11,840 --> 05:01:12,840
location over the Internet which is
6950
05:01:15,660 --> 05:01:16,660
represented by the cloud there are a few
6951
05:01:18,360 --> 05:01:19,360
security concerns that come with
6952
05:01:21,480 --> 05:01:22,480
um RDP and there is potential for
6953
05:01:25,138 --> 05:01:26,138
certain sort of computer attacks so
6954
05:01:27,600 --> 05:01:28,600
there are also non-microsoft variations
6955
05:01:29,878 --> 05:01:30,878
available such as something called our
6956
05:01:33,298 --> 05:01:34,298
desktop
6957
05:01:35,940 --> 05:01:36,940
for Unix
6958
05:01:38,820 --> 05:01:39,820
which if you are going to be doing a lot
6959
05:01:41,160 --> 05:01:42,160
of remoting you might want to look into
6960
05:01:43,440 --> 05:01:44,440
RDP by the way uses default Port
6961
05:01:47,180 --> 05:01:48,180
3389 although you can change that
6962
05:01:50,458 --> 05:01:51,458
usually as well when we're using RDP
6963
05:01:52,980 --> 05:01:53,980
we're also going to use it over what's
6964
05:01:54,718 --> 05:01:55,718
called a VPN or virtual private Network
6965
05:01:57,360 --> 05:01:58,360
which creates a tunnel
6966
05:02:01,440 --> 05:02:02,440
through which your connection occurs
6967
05:02:03,660 --> 05:02:04,660
this improves the security we were just
6968
05:02:06,060 --> 05:02:07,060
talking about so let's review what we've
6969
05:02:08,700 --> 05:02:09,700
just talked about first we talked about
6970
05:02:10,860 --> 05:02:11,860
a port being The Logical endpoint of a
6971
05:02:14,100 --> 05:02:15,100
connection
6972
05:02:15,180 --> 05:02:16,180
and then we outlined the port ranges
6973
05:02:19,378 --> 05:02:20,378
remember we had the well-known ports
6974
05:02:24,780 --> 05:02:25,780
the registered ports
6975
05:02:27,900 --> 05:02:28,900
and then the dynamic
6976
05:02:31,500 --> 05:02:32,500
or private or experimental ports what we
6977
05:02:35,458 --> 05:02:36,458
really want to uh learn for ourselves
6978
05:02:38,400 --> 05:02:39,400
are the well-known ports
6979
05:02:40,740 --> 05:02:41,740
I then outlined the most common
6980
05:02:42,840 --> 05:02:43,840
well-known default ports and their
6981
05:02:44,760 --> 05:02:45,760
protocols you want to memorize this
6982
05:02:48,240 --> 05:02:49,240
table
6983
05:02:49,980 --> 05:02:50,980
for the network plus exam
6984
05:02:54,540 --> 05:02:55,540
I guarantee you doing that will get you
6985
05:02:56,940 --> 05:02:57,940
a bunch of questions on the exam
6986
05:02:59,520 --> 05:03:00,520
finally we Define to describe some of
6987
05:03:01,798 --> 05:03:02,798
the specific ports and not only and we
6988
05:03:04,920 --> 05:03:05,920
looked not only at the protocol
6989
05:03:08,160 --> 05:03:09,160
and their protocols including FTP or the
6990
05:03:11,638 --> 05:03:12,638
file transfer protocol
6991
05:03:15,718 --> 05:03:16,718
ntp or the network
6992
05:03:19,320 --> 05:03:20,320
time protocol
6993
05:03:22,218 --> 05:03:23,218
SMTP or the simple mail
6994
05:03:27,660 --> 05:03:28,660
transfer
6995
05:03:29,878 --> 05:03:30,878
protocol
6996
05:03:31,620 --> 05:03:32,620
POP3 or the
6997
05:03:34,260 --> 05:03:35,260
post
6998
05:03:36,180 --> 05:03:37,180
office protocol
6999
05:03:39,000 --> 05:03:40,000
we also looked at
7000
05:03:40,860 --> 05:03:41,860
IMAP the internet
7001
05:03:46,138 --> 05:03:47,138
message access protocol and again all
7002
05:03:49,980 --> 05:03:50,980
three of these
7003
05:03:51,780 --> 05:03:52,780
have to do with email
7004
05:03:54,060 --> 05:03:55,060
we also looked at an ntp which is not
7005
05:03:57,958 --> 05:03:58,958
Network time protocol but the network
7006
05:04:00,980 --> 05:04:01,980
news transfer
7007
05:04:05,340 --> 05:04:06,340
protocol
7008
05:04:06,840 --> 05:04:07,840
we looked at two different versions of
7009
05:04:08,400 --> 05:04:09,400
HTTP one that is secure these allow for
7010
05:04:11,820 --> 05:04:12,820
browsing
7011
05:04:14,580 --> 05:04:15,580
and it stands for the hyper text
7012
05:04:16,700 --> 05:04:17,700
transfer protocol
7013
05:04:19,440 --> 05:04:20,440
which if you know HTML or the hypertext
7014
05:04:22,500 --> 05:04:23,500
markup language then that might be
7015
05:04:25,138 --> 05:04:26,138
familiar to you and finally looked at
7016
05:04:27,298 --> 05:04:28,298
RDP or the remote desktop protocol
7017
05:04:31,680 --> 05:04:32,680
I know this seems like a lot but I
7018
05:04:34,138 --> 05:04:35,138
guarantee memorizing all of these and
7019
05:04:36,298 --> 05:04:37,298
all of the numbers that they're
7020
05:04:37,500 --> 05:04:38,500
associated with is gonna help you so
7021
05:04:40,260 --> 05:04:41,260
much on the exam
7022
05:04:44,930 --> 05:04:45,930
[Music]
7023
05:05:04,878 --> 05:05:05,878
Network protocols and services
7024
05:05:08,718 --> 05:05:09,718
interoperability services
7025
05:05:11,760 --> 05:05:12,760
this word interoperability is a really
7026
05:05:14,218 --> 05:05:15,218
long one but it's also a good one
7027
05:05:15,798 --> 05:05:16,798
basically what this means is how
7028
05:05:18,840 --> 05:05:19,840
different types of operating systems and
7029
05:05:21,480 --> 05:05:22,480
computers can communicate with one
7030
05:05:23,638 --> 05:05:24,638
another over a similar Network and
7031
05:05:26,638 --> 05:05:27,638
that's what we're going to be discussing
7032
05:05:27,840 --> 05:05:28,840
in this module
7033
05:05:29,878 --> 05:05:30,878
so we're going to first cover what
7034
05:05:32,700 --> 05:05:33,700
interoperability services are in a
7035
05:05:34,798 --> 05:05:35,798
little more depth then we're going to
7036
05:05:36,600 --> 05:05:37,600
Define some specific services that
7037
05:05:39,298 --> 05:05:40,298
qualify as these particularly NFS or the
7038
05:05:43,320 --> 05:05:44,320
network
7039
05:05:45,200 --> 05:05:46,200
file system I'm sure you can imagine
7040
05:05:48,060 --> 05:05:49,060
what that is from its name we're also
7041
05:05:50,700 --> 05:05:51,700
going to look at SSH which is the secure
7042
05:05:53,520 --> 05:05:54,520
shell
7043
05:05:54,780 --> 05:05:55,780
and SCP secure
7044
05:05:58,680 --> 05:05:59,680
copy protocol remember every time we see
7045
05:06:01,798 --> 05:06:02,798
that s we want to think uh secure
7046
05:06:05,160 --> 05:06:06,160
security that's a great tip that'll help
7047
05:06:07,138 --> 05:06:08,138
you out on the test by the way secure
7048
05:06:09,120 --> 05:06:10,120
copy protocols similar to SFTP or the
7049
05:06:12,600 --> 05:06:13,600
secure file transfer protocol
7050
05:06:15,420 --> 05:06:16,420
we're then going to look at telnet or
7051
05:06:17,458 --> 05:06:18,458
the Telecommunications Network and SMB
7052
05:06:20,340 --> 05:06:21,340
or the server messenger block
7053
05:06:27,840 --> 05:06:28,840
which is what allows us to share for
7054
05:06:30,540 --> 05:06:31,540
instance files and printers
7055
05:06:33,000 --> 05:06:34,000
we're also going to look at ldap or
7056
05:06:35,340 --> 05:06:36,340
lightweight directory access protocol
7057
05:06:37,560 --> 05:06:38,560
and that word directory is important as
7058
05:06:40,260 --> 05:06:41,260
it allows us to manage users in our
7059
05:06:43,260 --> 05:06:44,260
Network
7060
05:06:44,458 --> 05:06:45,458
mm zero conf in networking which also
7061
05:06:48,360 --> 05:06:49,360
stands for zero configuration networking
7062
05:06:50,820 --> 05:06:51,820
a set of protocols that allows us to
7063
05:06:53,638 --> 05:06:54,638
sort of plug in and go
7064
05:06:56,760 --> 05:06:57,760
without having to do a lot of advanced
7065
05:06:58,980 --> 05:06:59,980
configuration and setup this is what
7066
05:07:01,320 --> 05:07:02,320
allows us to have very easy Plug and
7067
05:07:04,020 --> 05:07:05,020
Play network devices such as our Soho
7068
05:07:07,020 --> 05:07:08,020
routers which is a good way to think
7069
05:07:08,820 --> 05:07:09,820
about it however it's also deployed in
7070
05:07:10,980 --> 05:07:11,980
much larger operations in order to ease
7071
05:07:13,260 --> 05:07:14,260
the burden on administrators and
7072
05:07:15,360 --> 05:07:16,360
technicians
7073
05:07:17,940 --> 05:07:18,940
so in the previous module we discussed
7074
05:07:21,000 --> 05:07:22,000
several different protocols that were
7075
05:07:23,520 --> 05:07:24,520
used in the tcpip protocol suite and
7076
05:07:28,320 --> 05:07:29,320
these allowed us to do a lot of
7077
05:07:30,360 --> 05:07:31,360
different things by the way tcpip which
7078
05:07:33,480 --> 05:07:34,480
is what basically allows us to
7079
05:07:35,700 --> 05:07:36,700
communicate over the network in general
7080
05:07:37,860 --> 05:07:38,860
is going to be discussed in more detail
7081
05:07:40,500 --> 05:07:41,500
in depth later on in this course
7082
05:07:43,138 --> 05:07:44,138
now because not all computers are made
7083
05:07:46,200 --> 05:07:47,200
the same or by the same people or
7084
05:07:48,840 --> 05:07:49,840
individuals certain protocols and
7085
05:07:52,138 --> 05:07:53,138
services need to be in place to allow
7086
05:07:54,980 --> 05:07:55,980
dissimilar systems such as PCS and Macs
7087
05:07:58,920 --> 05:07:59,920
to be able to interact with one another
7088
05:08:01,458 --> 05:08:02,458
so tcpip also contains these
7089
05:08:05,540 --> 05:08:06,540
interoperability services that allow
7090
05:08:08,420 --> 05:08:09,420
dissimilar services or systems to share
7091
05:08:12,120 --> 05:08:13,120
resources and communicate efficiently
7092
05:08:15,000 --> 05:08:16,000
and securely which is important if I
7093
05:08:18,000 --> 05:08:19,000
want to make sure that no one is reading
7094
05:08:20,520 --> 05:08:21,520
all of the information I'm sending
7095
05:08:22,080 --> 05:08:23,080
between computers so these Services is
7096
05:08:24,600 --> 05:08:25,600
what we're going to spend the rest of
7097
05:08:26,040 --> 05:08:27,040
this module discussing
7098
05:08:27,900 --> 05:08:28,900
now the first service is the network
7099
05:08:30,480 --> 05:08:31,480
file system
7100
05:08:32,400 --> 05:08:33,400
it's an application that allows users to
7101
05:08:35,760 --> 05:08:36,760
remotely access resources and files a
7102
05:08:40,320 --> 05:08:41,320
resource being for instance a printer
7103
05:08:43,260 --> 05:08:44,260
and a file being like a Word document as
7104
05:08:46,798 --> 05:08:47,798
though they were located on a local
7105
05:08:48,900 --> 05:08:49,900
machine even though they're someplace
7106
05:08:51,060 --> 05:08:52,060
else
7107
05:08:52,020 --> 05:08:53,020
this service is used for systems that
7108
05:08:54,540 --> 05:08:55,540
are typically not the same such as Unix
7109
05:08:57,958 --> 05:08:58,958
which is the larger version or the
7110
05:09:00,958 --> 05:09:01,958
commercial version of Linux and
7111
05:09:04,138 --> 05:09:05,138
Microsoft systems now NFS functions
7112
05:09:07,760 --> 05:09:08,760
independently of the operating system
7113
05:09:10,320 --> 05:09:11,320
the computer system it's installed on
7114
05:09:13,080 --> 05:09:14,080
and the network architecture this means
7115
05:09:16,500 --> 05:09:17,500
that NFS is going to perform its
7116
05:09:18,718 --> 05:09:19,718
functions regardless of where it's
7117
05:09:20,520 --> 05:09:21,520
installed and since it's what we call an
7118
05:09:23,638 --> 05:09:24,638
open standard
7119
05:09:26,160 --> 05:09:27,160
it allows anyone to implement it
7120
05:09:30,660 --> 05:09:31,660
it also listens on Port 2049 by default
7121
05:09:34,560 --> 05:09:35,560
but I wouldn't worry about memorizing
7122
05:09:36,660 --> 05:09:37,660
that for the test
7123
05:09:38,458 --> 05:09:39,458
next SSH or the secure shell is one of
7124
05:09:43,080 --> 05:09:44,080
the preferred session initiating
7125
05:09:45,780 --> 05:09:46,780
programs that allows us to connect to a
7126
05:09:49,378 --> 05:09:50,378
remote computer
7127
05:09:50,878 --> 05:09:51,878
it creates a secure Connection by using
7128
05:09:53,940 --> 05:09:54,940
strong authentication mechanisms and it
7129
05:09:56,878 --> 05:09:57,878
lets users log on to remote computers
7130
05:09:59,520 --> 05:10:00,520
with different systems independent of
7131
05:10:02,218 --> 05:10:03,218
the type of system you're currently on
7132
05:10:04,440 --> 05:10:05,440
with SSH the secure shell the entire
7133
05:10:07,920 --> 05:10:08,920
connection is encrypted including the
7134
05:10:10,860 --> 05:10:11,860
password and the login session
7135
05:10:13,560 --> 05:10:14,560
it's all compatible with a lot of
7136
05:10:15,540 --> 05:10:16,540
different systems including Linux Macs
7137
05:10:18,780 --> 05:10:19,780
and PCs and so on now there are actually
7138
05:10:21,540 --> 05:10:22,540
two different versions of secure show
7139
05:10:24,120 --> 05:10:25,120
ssh1
7140
05:10:26,940 --> 05:10:27,940
and ssh2
7141
05:10:31,500 --> 05:10:32,500
these two versions are not compatible
7142
05:10:34,080 --> 05:10:35,080
with one another which is important to
7143
05:10:36,840 --> 05:10:37,840
know
7144
05:10:37,560 --> 05:10:38,560
because they each encrypt different
7145
05:10:39,958 --> 05:10:40,958
parts of the data packet and they employ
7146
05:10:42,660 --> 05:10:43,660
different types of encryption methods
7147
05:10:45,180 --> 05:10:46,180
which we'll talk about later however the
7148
05:10:47,700 --> 05:10:48,700
most important thing to know is that SSH
7149
05:10:50,100 --> 05:10:51,100
2 is more secure than ssh1 and so in
7150
05:10:55,440 --> 05:10:56,440
most cases we want to use that this is
7151
05:10:57,780 --> 05:10:58,780
because it does not use server Keys ssh1
7152
05:11:01,440 --> 05:11:02,440
doesn't which are keys that are
7153
05:11:05,280 --> 05:11:06,280
temporary and protect other aspects of
7154
05:11:08,638 --> 05:11:09,638
the encryption process it's a bit
7155
05:11:10,620 --> 05:11:11,620
complex and over the course of and over
7156
05:11:13,320 --> 05:11:14,320
the objectives of this course however
7157
05:11:16,320 --> 05:11:17,320
SSH 2 does contain another protocol
7158
05:11:19,260 --> 05:11:20,260
called SFTP
7159
05:11:23,280 --> 05:11:24,280
an SFTP or the secure file transfer
7160
05:11:27,298 --> 05:11:28,298
protocol
7161
05:11:28,740 --> 05:11:29,740
is a secure replacement for the unsecure
7162
05:11:31,980 --> 05:11:32,980
version of plain old FTP and it still
7163
05:11:35,400 --> 05:11:36,400
uses the same port as SSH which if you
7164
05:11:39,780 --> 05:11:40,780
recall is port 22.
7165
05:11:43,500 --> 05:11:44,500
so it's important to know that if we're
7166
05:11:46,138 --> 05:11:47,138
going to be using SFTP remember FTP uses
7167
05:11:49,798 --> 05:11:50,798
20 and 21 if we're using SFTP we're
7168
05:11:53,520 --> 05:11:54,520
using Port 22. now similar to SFTP is
7169
05:11:57,600 --> 05:11:58,600
SCP or the secure copy protocol which is
7170
05:12:02,280 --> 05:12:03,280
a secure method of copying files between
7171
05:12:04,860 --> 05:12:05,860
remote devices just like FTP or SFTP it
7172
05:12:09,420 --> 05:12:10,420
utilizes the same Portis SSH just like
7173
05:12:12,540 --> 05:12:13,540
SFTP and it's compatible with a lot of
7174
05:12:15,298 --> 05:12:16,298
different operating systems to implement
7175
05:12:17,878 --> 05:12:18,878
SCP you can initiate it via a command
7176
05:12:21,180 --> 05:12:22,180
line utility that uses either SCP or
7177
05:12:25,020 --> 05:12:26,020
SFTP to perform some secure copying the
7178
05:12:28,740 --> 05:12:29,740
important thing here to know for the
7179
05:12:30,360 --> 05:12:31,360
network plus exam is not when you would
7180
05:12:32,820 --> 05:12:33,820
use SCP over SFTP which is a little bit
7181
05:12:36,240 --> 05:12:37,240
more complex but rather to realize that
7182
05:12:39,360 --> 05:12:40,360
SCP is a secure method of copying as is
7183
05:12:43,020 --> 05:12:44,020
as FTP that's how you're going to see
7184
05:12:45,900 --> 05:12:46,900
this pop up on the exam now in contrast
7185
05:12:48,840 --> 05:12:49,840
to all of this secure Communications I
7186
05:12:51,600 --> 05:12:52,600
want to talk about telnet or the
7187
05:12:53,878 --> 05:12:54,878
Telecommunications Network which is a
7188
05:12:56,760 --> 05:12:57,760
terminal emulations protocol what this
7189
05:12:59,760 --> 05:13:00,760
means is that it's only simulating a
7190
05:13:02,340 --> 05:13:03,340
session on the machine it is being
7191
05:13:04,500 --> 05:13:05,500
initiated on when you connect to a
7192
05:13:06,780 --> 05:13:07,780
machine via a terminal by using telnet
7193
05:13:10,320 --> 05:13:11,320
the machine is translating your
7194
05:13:12,298 --> 05:13:13,298
keystrokes into instructions that the
7195
05:13:14,820 --> 05:13:15,820
Remote device understands and it
7196
05:13:17,280 --> 05:13:18,280
displays those instructions and the
7197
05:13:20,218 --> 05:13:21,218
responses back to you in a graphical or
7198
05:13:22,980 --> 05:13:23,980
command line manner
7199
05:13:25,020 --> 05:13:26,020
telnet is an unsecure protocol which is
7200
05:13:28,080 --> 05:13:29,080
why we don't use it as much as SSH
7201
05:13:30,060 --> 05:13:31,060
anymore and this is important to keep in
7202
05:13:32,638 --> 05:13:33,638
mind
7203
05:13:33,718 --> 05:13:34,718
so when you send the password over
7204
05:13:35,878 --> 05:13:36,878
telnet it's actually in what we call
7205
05:13:38,100 --> 05:13:39,100
plain text
7206
05:13:40,080 --> 05:13:41,080
whereas as we mentioned with SSH it
7207
05:13:45,000 --> 05:13:46,000
transmits the password encrypted so if
7208
05:13:47,520 --> 05:13:48,520
someone is reading the packets that are
7209
05:13:49,200 --> 05:13:50,200
going back and forth they won't be able
7210
05:13:50,878 --> 05:13:51,878
to hack your system if you're using SSH
7211
05:13:53,160 --> 05:13:54,160
whereas with telnet they'd be able to
7212
05:13:54,958 --> 05:13:55,958
read your password now telnet uses Port
7213
05:13:57,840 --> 05:13:58,840
23 by default which is important to know
7214
05:14:00,780 --> 05:14:01,780
however you could configure it to use
7215
05:14:03,120 --> 05:14:04,120
another Port as long as the remote
7216
05:14:04,980 --> 05:14:05,980
machine is also configured to use that
7217
05:14:07,260 --> 05:14:08,260
same port with telnet you can actually
7218
05:14:09,360 --> 05:14:10,360
connect to any host that's running the
7219
05:14:11,458 --> 05:14:12,458
telnet service or Daemon which again the
7220
05:14:14,700 --> 05:14:15,700
word Daemon is a Unix version of service
7221
05:14:19,940 --> 05:14:20,940
SMB or the server message block which by
7222
05:14:23,580 --> 05:14:24,580
the way is also known as cifs or the
7223
05:14:27,360 --> 05:14:28,360
common internet file system is a
7224
05:14:29,940 --> 05:14:30,940
protocol that's mainly used to provide
7225
05:14:32,040 --> 05:14:33,040
shared access to files peripheral
7226
05:14:35,638 --> 05:14:36,638
devices like printers most most of the
7227
05:14:38,878 --> 05:14:39,878
time
7228
05:14:40,740 --> 05:14:41,740
and also access to serial ports and
7229
05:14:43,980 --> 05:14:44,980
other communication between nodes on a
7230
05:14:46,200 --> 05:14:47,200
network Windows systems used SMB
7231
05:14:49,580 --> 05:14:50,580
primarily before the introduction of
7232
05:14:51,900 --> 05:14:52,900
something called uh active directories
7233
05:14:55,740 --> 05:14:56,740
which we'll talk more about a little bit
7234
05:14:58,320 --> 05:14:59,320
later this is currently what's used in
7235
05:15:01,620 --> 05:15:02,620
Microsoft networks now Windows services
7236
05:15:04,378 --> 05:15:05,378
that correspond are called server
7237
05:15:07,560 --> 05:15:08,560
services for the server component and
7238
05:15:10,440 --> 05:15:11,440
workstation services for the client
7239
05:15:13,260 --> 05:15:14,260
component
7240
05:15:14,580 --> 05:15:15,580
now for example the primary
7241
05:15:16,798 --> 05:15:17,798
functionality that SMB is typically most
7242
05:15:20,458 --> 05:15:21,458
known for is when client computers want
7243
05:15:23,160 --> 05:15:24,160
to access files systems or printers on a
7244
05:15:26,580 --> 05:15:27,580
shared network or server this is when
7245
05:15:29,100 --> 05:15:30,100
SMB is most often used
7246
05:15:32,480 --> 05:15:33,480
Samba which you may have seen if you've
7247
05:15:35,520 --> 05:15:36,520
ever dealt with a Mac or a Linux
7248
05:15:37,860 --> 05:15:38,860
computer is free software that's a
7249
05:15:40,620 --> 05:15:41,620
re-implementation of the SMB or cifs
7250
05:15:44,280 --> 05:15:45,280
networking protocol for other systems
7251
05:15:47,060 --> 05:15:48,060
even though SMB is primarily used or was
7252
05:15:51,180 --> 05:15:52,180
primarily used with Microsoft systems
7253
05:15:53,218 --> 05:15:54,218
there are still other products that use
7254
05:15:55,320 --> 05:15:56,320
SMB for file sharing in different
7255
05:15:57,718 --> 05:15:58,718
operating systems which is why it's
7256
05:15:59,638 --> 05:16:00,638
important that we still familiarize
7257
05:16:01,260 --> 05:16:02,260
ourselves with it
7258
05:16:02,958 --> 05:16:03,958
ldap stands for the lightweight
7259
05:16:05,900 --> 05:16:06,900
directory access protocol and this is
7260
05:16:09,000 --> 05:16:10,000
what defines how a user can access files
7261
05:16:12,440 --> 05:16:13,440
resources or share directory data and
7262
05:16:15,480 --> 05:16:16,480
perform operations on a server in a
7263
05:16:18,298 --> 05:16:19,298
tcpip network now this is not how they
7264
05:16:22,980 --> 05:16:23,980
access it this simply defines how a user
7265
05:16:26,580 --> 05:16:27,580
can access it meaning that we're really
7266
05:16:29,400 --> 05:16:30,400
talking about here are users
7267
05:16:32,218 --> 05:16:33,218
and permissions
7268
05:16:37,260 --> 05:16:38,260
so basically ldap is the protocol that
7269
05:16:40,680 --> 05:16:41,680
controls how users manage directory
7270
05:16:43,740 --> 05:16:44,740
information such as data about users
7271
05:16:47,180 --> 05:16:48,180
devices permissions searching and other
7272
05:16:51,600 --> 05:16:52,600
tasks in most networks we're going to
7273
05:16:53,760 --> 05:16:54,760
deal with this a little more in depth
7274
05:16:55,378 --> 05:16:56,378
later on as well now it was designed to
7275
05:16:58,080 --> 05:16:59,080
be used on the internet and it relies
7276
05:17:00,540 --> 05:17:01,540
heavily on DNS the domain name service
7277
05:17:04,500 --> 05:17:05,500
which we talked about is a way of
7278
05:17:06,840 --> 05:17:07,840
converting say google.com into its IP
7279
05:17:10,798 --> 05:17:11,798
address we're going to discuss DNS in
7280
05:17:13,378 --> 05:17:14,378
Greater detail in another module now
7281
05:17:16,080 --> 05:17:17,080
Microsoft's active directory service
7282
05:17:18,298 --> 05:17:19,298
which we just mentioned and novell's NDS
7283
05:17:22,620 --> 05:17:23,620
and e-directory services Novell being
7284
05:17:25,740 --> 05:17:26,740
another networking operating system as
7285
05:17:28,680 --> 05:17:29,680
well as Apple's open directory directory
7286
05:17:32,100 --> 05:17:33,100
system all use ldap now the reason it's
7287
05:17:36,600 --> 05:17:37,600
called like lightweight is because it
7288
05:17:40,080 --> 05:17:41,080
was not as Network intensive as its
7289
05:17:42,718 --> 05:17:43,718
predecessor which was simply the
7290
05:17:44,760 --> 05:17:45,760
directory access Protocol no need to
7291
05:17:47,280 --> 05:17:48,280
know that but I just wanted to explain
7292
05:17:48,718 --> 05:17:49,718
the reasoning behind that light weight
7293
05:17:51,480 --> 05:17:52,480
in there
7294
05:17:52,500 --> 05:17:53,500
also it's important to know that port
7295
05:17:54,718 --> 05:17:55,718
389 is used by default for all the
7296
05:17:58,378 --> 05:17:59,378
communication of the requests for
7297
05:18:00,660 --> 05:18:01,660
information and objects finally zero
7298
05:18:04,200 --> 05:18:05,200
conf or zero configuration
7299
05:18:08,958 --> 05:18:09,958
networking is a set of standards that
7300
05:18:12,180 --> 05:18:13,180
was established to allow users the
7301
05:18:14,218 --> 05:18:15,218
ability to have network connectivity out
7302
05:18:17,820 --> 05:18:18,820
of the box or Plug and Play or without
7303
05:18:21,600 --> 05:18:22,600
the need for any sort of technical
7304
05:18:24,298 --> 05:18:25,298
change or configuration zero con capable
7305
05:18:28,200 --> 05:18:29,200
protocols will generally use Mac
7306
05:18:30,840 --> 05:18:31,840
addresses or the physical addresses as
7307
05:18:33,718 --> 05:18:34,718
they are unique to each device with a
7308
05:18:36,660 --> 05:18:37,660
NIC or network interface card
7309
05:18:39,540 --> 05:18:40,540
in order for devices
7310
05:18:41,840 --> 05:18:42,840
to fit into a zero conf standard they
7311
05:18:46,138 --> 05:18:47,138
have to fit or meet four qualifications
7312
05:18:49,200 --> 05:18:50,200
or functions first the network address
7313
05:18:52,680 --> 05:18:53,680
assignment must be automatic if you
7314
05:18:55,798 --> 05:18:56,798
recall from a plus and this is something
7315
05:18:57,360 --> 05:18:58,360
we'll talk about a bit later this is
7316
05:18:59,218 --> 05:19:00,218
what we use when we're using DHCP
7317
05:19:03,298 --> 05:19:04,298
second automatic multicast address
7318
05:19:06,920 --> 05:19:07,920
assignment must be implemented which is
7319
05:19:10,740 --> 05:19:11,740
also related to the DHCP standard third
7320
05:19:14,298 --> 05:19:15,298
automatic translation between Network
7321
05:19:17,100 --> 05:19:18,100
names and addresses must exist this is
7322
05:19:19,860 --> 05:19:20,860
what we talk about when we deal with DNS
7323
05:19:22,620 --> 05:19:23,620
finally discovery of Network Services or
7324
05:19:26,400 --> 05:19:27,400
the location by the protocol and the
7325
05:19:28,680 --> 05:19:29,680
name is required meaning that it must be
7326
05:19:31,920 --> 05:19:32,920
able to find all of this information
7327
05:19:34,200 --> 05:19:35,200
when it goes on the network
7328
05:19:36,180 --> 05:19:37,180
automatically this is what allows users
7329
05:19:39,180 --> 05:19:40,180
to be able to purchase a router from the
7330
05:19:41,700 --> 05:19:42,700
local Best Buy or electronics store take
7331
05:19:45,000 --> 05:19:46,000
it home plug it into their ISB or
7332
05:19:47,878 --> 05:19:48,878
Internet service provider connection and
7333
05:19:50,040 --> 05:19:51,040
automatically have it work automatically
7334
05:19:51,958 --> 05:19:52,958
another implementation by the way of
7335
05:19:54,060 --> 05:19:55,060
this is a configuration and networking
7336
05:19:56,280 --> 05:19:57,280
called
7337
05:19:57,378 --> 05:19:58,378
you PNP
7338
05:19:59,820 --> 05:20:00,820
or
7339
05:20:01,378 --> 05:20:02,378
Universal
7340
05:20:04,680 --> 05:20:05,680
plug
7341
05:20:07,320 --> 05:20:08,320
and play
7342
05:20:09,660 --> 05:20:10,660
so to recap what we've talked about we
7343
05:20:11,878 --> 05:20:12,878
talked about interoperability Services
7344
05:20:13,798 --> 05:20:14,798
which allows for instance a PC and a Mac
7345
05:20:17,480 --> 05:20:18,480
to communicate flawlessly over a network
7346
05:20:20,340 --> 05:20:21,340
we then talked about the network file
7347
05:20:23,458 --> 05:20:24,458
service
7348
05:20:26,360 --> 05:20:27,360
SSH and SCP SSH being a secure shell
7349
05:20:34,260 --> 05:20:35,260
working on
7350
05:20:37,680 --> 05:20:38,680
Port 22
7351
05:20:39,900 --> 05:20:40,900
and SCP being the secure
7352
05:20:43,920 --> 05:20:44,920
copy protocol
7353
05:20:45,840 --> 05:20:46,840
similar
7354
05:20:47,638 --> 05:20:48,638
to
7355
05:20:48,440 --> 05:20:49,440
SFTP the secure file transfer protocol
7356
05:20:51,360 --> 05:20:52,360
we looked at telnet which is sort of a
7357
05:20:54,660 --> 05:20:55,660
plain text version of SSH so it's been
7358
05:20:58,138 --> 05:20:59,138
replaced by it and SMB or the server
7359
05:21:01,440 --> 05:21:02,440
message block allowing us to share files
7360
05:21:05,820 --> 05:21:06,820
and resources
7361
05:21:09,298 --> 05:21:10,298
between different types of systems
7362
05:21:12,360 --> 05:21:13,360
finally we described and defined ldap or
7363
05:21:15,958 --> 05:21:16,958
the lightweight directory access
7364
05:21:18,060 --> 05:21:19,060
protocol which defines users and their
7365
05:21:22,020 --> 05:21:23,020
ability to access all this stuff on the
7366
05:21:24,360 --> 05:21:25,360
network and then we explained zero conf
7367
05:21:27,540 --> 05:21:28,540
or zero configuration in networking
7368
05:21:31,200 --> 05:21:32,200
which allows us to plug up a device and
7369
05:21:34,680 --> 05:21:35,680
have it work almost instantaneously
7370
05:21:40,690 --> 05:21:41,690
[Music]
7371
05:21:49,700 --> 05:21:50,700
thank you
7372
05:21:57,120 --> 05:21:58,120
welcome to module 5 lesson 1 ethernet
7373
05:22:00,000 --> 05:22:01,000
standards pretty meaty subject this
7374
05:22:03,420 --> 05:22:04,420
because it's got a whole bunch of
7375
05:22:05,160 --> 05:22:06,160
standards and information as well as
7376
05:22:07,620 --> 05:22:08,620
history to fit in
7377
05:22:09,480 --> 05:22:10,480
what is ethernet the history why the
7378
05:22:12,600 --> 05:22:13,600
name just in case you wanted to know I
7379
05:22:14,820 --> 05:22:15,820
guess
7380
05:22:15,718 --> 05:22:16,718
introduction of ethernet standards
7381
05:22:18,900 --> 05:22:19,900
the Archer Police standard as well ATO
7382
05:22:21,718 --> 05:22:22,718
2.3 which you'll need to be familiar
7383
05:22:23,340 --> 05:22:24,340
with which defines ethernet
7384
05:22:25,560 --> 05:22:26,560
the IEEE as well what they do and their
7385
05:22:28,980 --> 05:22:29,980
remit per view
7386
05:22:32,340 --> 05:22:33,340
uh based on a Broadband some history
7387
05:22:34,920 --> 05:22:35,920
really of the early days of ethernet
7388
05:22:37,320 --> 05:22:38,320
networking
7389
05:22:38,760 --> 05:22:39,760
which are depending on how old you are
7390
05:22:40,740 --> 05:22:41,740
you may be familiar with
7391
05:22:42,718 --> 05:22:43,718
some of the naming conventions uh the
7392
05:22:45,298 --> 05:22:46,298
early days the early specifications
7393
05:22:47,160 --> 05:22:48,160
thick nets in net
7394
05:22:50,820 --> 05:22:51,820
and some of the standards here which
7395
05:22:52,860 --> 05:22:53,860
we're going to run through which you'll
7396
05:22:54,420 --> 05:22:55,420
need to be familiar with because you
7397
05:22:55,920 --> 05:22:56,920
could be asked a question
7398
05:22:58,320 --> 05:22:59,320
so that's a good reason as any uh
7399
05:23:01,920 --> 05:23:02,920
ethernet it's the was or is the first
7400
05:23:04,620 --> 05:23:05,620
high-speed land technology that in
7401
05:23:07,080 --> 05:23:08,080
Connected computers high speed Laser
7402
05:23:10,320 --> 05:23:11,320
Printers obviously in the early days
7403
05:23:12,420 --> 05:23:13,420
there needed to be some agreed format
7404
05:23:14,940 --> 05:23:15,940
for um Internet working devices to
7405
05:23:17,700 --> 05:23:18,700
communicate
7406
05:23:19,020 --> 05:23:20,020
actually invented by a guy called Bob
7407
05:23:21,000 --> 05:23:22,000
Metcalfe back in
7408
05:23:23,298 --> 05:23:24,298
1973. it was remarkable in as much that
7409
05:23:26,100 --> 05:23:27,100
at the time competing was dominated by
7410
05:23:28,560 --> 05:23:29,560
some very large and expensive mainframe
7411
05:23:32,160 --> 05:23:33,160
computers
7412
05:23:33,660 --> 05:23:34,660
um to name IBM as a one of the main
7413
05:23:36,420 --> 05:23:37,420
players at the time
7414
05:23:37,798 --> 05:23:38,798
it's only a few people could actually
7415
05:23:39,240 --> 05:23:40,240
afford to buy the mainframes and the
7416
05:23:41,940 --> 05:23:42,940
information required in order to use
7417
05:23:45,298 --> 05:23:46,298
them operate support and maintain was
7418
05:23:47,520 --> 05:23:48,520
only known to a few people at the time
7419
05:23:50,520 --> 05:23:51,520
so Bob actually changed the name of his
7420
05:23:52,620 --> 05:23:53,620
first network from alto Alor Network to
7421
05:23:55,920 --> 05:23:56,920
ethernet thankfully otherwise would all
7422
05:23:58,500 --> 05:23:59,500
be referred to it as alto Aloha which um
7423
05:24:02,580 --> 05:24:03,580
be a bit strange
7424
05:24:05,458 --> 05:24:06,458
why the name he um Bob's experimental
7425
05:24:09,360 --> 05:24:10,360
Network the physical medium
7426
05:24:11,218 --> 05:24:12,218
or the cable to carry out all the bits
7427
05:24:14,458 --> 05:24:15,458
to describe the important feature Bob
7428
05:24:16,440 --> 05:24:17,440
named the network based on the word
7429
05:24:18,060 --> 05:24:19,060
ether
7430
05:24:19,080 --> 05:24:20,080
the old um luminous lumini Ferrera
7431
05:24:22,920 --> 05:24:23,920
Ferris ether was once considered the
7432
05:24:24,900 --> 05:24:25,900
medium for the propagation of
7433
05:24:27,560 --> 05:24:28,560
electromagnetic waves
7434
05:24:30,180 --> 05:24:31,180
so there are some mythical background in
7435
05:24:33,120 --> 05:24:34,120
it
7436
05:24:34,860 --> 05:24:35,860
and first standardized by the Consortium
7437
05:24:37,440 --> 05:24:38,440
of deck Intel Xerox or Dix
7438
05:24:41,760 --> 05:24:42,760
later actually standardized by the IEEE
7439
05:24:45,860 --> 05:24:46,860
standards defined several aspects that
7440
05:24:48,060 --> 05:24:49,060
make data transmission possible this is
7441
05:24:50,280 --> 05:24:51,280
their job
7442
05:24:51,840 --> 05:24:52,840
term ethernet is used to refer to both
7443
05:24:54,060 --> 05:24:55,060
the original Dix ethernet which we'll
7444
05:24:56,280 --> 05:24:57,280
rarely talk about unless we're doing and
7445
05:24:58,620 --> 05:24:59,620
talking in the context of exams and the
7446
05:25:01,340 --> 05:25:02,340
802.3 specification which specifies
7447
05:25:04,400 --> 05:25:05,400
ethernet old and new
7448
05:25:08,820 --> 05:25:09,820
so 802.3 is an international standard
7449
05:25:11,280 --> 05:25:12,280
for local area networks and metropolitan
7450
05:25:13,680 --> 05:25:14,680
area networks that employs the carrier
7451
05:25:16,200 --> 05:25:17,200
sensor multiple access with Collision
7452
05:25:18,360 --> 05:25:19,360
detection
7453
05:25:20,040 --> 05:25:21,040
the ethernet protocol frame format for
7454
05:25:23,160 --> 05:25:24,160
communication
7455
05:25:24,840 --> 05:25:25,840
the IEEE is the institute for electrical
7456
05:25:27,298 --> 05:25:28,298
and electronic engineers
7457
05:25:30,000 --> 05:25:31,000
uh largest Professional Association
7458
05:25:34,260 --> 05:25:35,260
um for the advancement of Technology
7459
05:25:38,520 --> 05:25:39,520
it has more than uh 400 000 members
7460
05:25:41,940 --> 05:25:42,940
spanning 100 and more than 160 countries
7461
05:25:46,138 --> 05:25:47,138
so what do they do
7462
05:25:48,298 --> 05:25:49,298
they provide Society Publications they
7463
05:25:51,360 --> 05:25:52,360
develop on new and emerging technology
7464
05:25:53,760 --> 05:25:54,760
standards they also have conferences
7465
05:25:55,860 --> 05:25:56,860
that various Network Engineers can
7466
05:25:57,660 --> 05:25:58,660
attend to swap ideas and Advance the
7467
05:26:01,560 --> 05:26:02,560
technology
7468
05:26:03,540 --> 05:26:04,540
uh fortunately I'm not um this the
7469
05:26:06,240 --> 05:26:07,240
points aren't sliding in as they should
7470
05:26:08,580 --> 05:26:09,580
be so um all the information is
7471
05:26:10,440 --> 05:26:11,440
appearing at the same time sorry
7472
05:26:12,540 --> 05:26:13,540
so the ieee's leading developer of
7473
05:26:14,638 --> 05:26:15,638
international standards they include the
7474
05:26:17,040 --> 05:26:18,040
802 standards which are for lands and
7475
05:26:19,680 --> 05:26:20,680
mans and wireless local area networks
7476
05:26:22,620 --> 05:26:23,620
also which will refer to usually as
7477
05:26:24,780 --> 05:26:25,780
Wi-Fi you'll see the little stickers on
7478
05:26:27,060 --> 05:26:28,060
Wi-Fi devices and when you go to cafes
7479
05:26:30,120 --> 05:26:31,120
they may well have a Wi-Fi sticker to
7480
05:26:32,638 --> 05:26:33,638
say them they give a wireless access
7481
05:26:36,180 --> 05:26:37,180
and so ethernet's the most popular today
7482
05:26:38,900 --> 05:26:39,900
it's everywhere basically making
7483
05:26:41,040 --> 05:26:42,040
communication possible for pretty much
7484
05:26:43,500 --> 05:26:44,500
everyone and mainly popular because of
7485
05:26:47,700 --> 05:26:48,700
um the fact is economical to use it uses
7486
05:26:50,400 --> 05:26:51,400
high speed it's reliable and it's easy
7487
05:26:52,798 --> 05:26:53,798
to install and maintain also free to use
7488
05:26:55,680 --> 05:26:56,680
the standards
7489
05:26:57,060 --> 05:26:58,060
um like TCP if you used a custom
7490
05:27:01,378 --> 05:27:02,378
Solution by another
7491
05:27:04,740 --> 05:27:05,740
um Creator then you'd obviously have to
7492
05:27:07,080 --> 05:27:08,080
pay to use all of their
7493
05:27:09,540 --> 05:27:10,540
um specifications and standards
7494
05:27:11,940 --> 05:27:12,940
so the early ethernet run over what was
7495
05:27:14,160 --> 05:27:15,160
known as coaxial cables
7496
05:27:16,920 --> 05:27:17,920
um modern ethernet don't do that anymore
7497
05:27:18,840 --> 05:27:19,840
because of the limitations of speed and
7498
05:27:20,940 --> 05:27:21,940
troubleshooting they use a mixture of
7499
05:27:23,340 --> 05:27:24,340
copper and fiber depending on um the
7500
05:27:27,000 --> 05:27:28,000
location and how much what the budgets
7501
05:27:29,878 --> 05:27:30,878
of the various devices or
7502
05:27:32,458 --> 05:27:33,458
um local government authorities have
7503
05:27:35,580 --> 05:27:36,580
based on broadband is the term
7504
05:27:38,160 --> 05:27:39,160
synonymous with ethernet the band is
7505
05:27:41,218 --> 05:27:42,218
actually referred to the bandwidth in
7506
05:27:43,860 --> 05:27:44,860
context of the transmission
7507
05:27:47,060 --> 05:27:48,060
uh Broadband is a broadband system a
7508
05:27:49,920 --> 05:27:50,920
whole band of transmission medium is
7509
05:27:51,958 --> 05:27:52,958
shared dividing it into pieces called
7510
05:27:53,940 --> 05:27:54,940
channels
7511
05:27:55,378 --> 05:27:56,378
each channel will have the portion of
7512
05:27:57,600 --> 05:27:58,600
the whole band multiple channels will
7513
05:28:00,420 --> 05:28:01,420
serve as multiple signal carriers each
7514
05:28:02,700 --> 05:28:03,700
carrying its own data on the same
7515
05:28:04,378 --> 05:28:05,378
transmission medium so basically we're
7516
05:28:06,540 --> 05:28:07,540
all sharing the same medium and the
7517
05:28:10,320 --> 05:28:11,320
local ratio I think for my Broadband
7518
05:28:12,298 --> 05:28:13,298
here is
7519
05:28:14,280 --> 05:28:15,280
um 30 to 1 so 30 users will use one
7520
05:28:17,638 --> 05:28:18,638
connection to the local
7521
05:28:20,280 --> 05:28:21,280
um switch provided by the telephone
7522
05:28:22,200 --> 05:28:23,200
company
7523
05:28:23,878 --> 05:28:24,878
base band in the baseband system the
7524
05:28:26,040 --> 05:28:27,040
entire band of the transmission medium
7525
05:28:27,660 --> 05:28:28,660
will be used as a signal carrier
7526
05:28:31,260 --> 05:28:32,260
naming conventions the ethernet
7527
05:28:33,660 --> 05:28:34,660
standards username and Convention that
7528
05:28:35,458 --> 05:28:36,458
houses determine a few things the speed
7529
05:28:38,218 --> 05:28:39,218
of the transmission the signaling type
7530
05:28:40,138 --> 05:28:41,138
and the length of the cable
7531
05:28:42,298 --> 05:28:43,298
uh cable type used as well for example
7532
05:28:45,180 --> 05:28:46,180
10 base 5 really old standard this it
7533
05:28:49,378 --> 05:28:50,378
was been phased out in the well late 90s
7534
05:28:54,240 --> 05:28:55,240
I think when I was
7535
05:28:55,920 --> 05:28:56,920
um just getting into networking really
7536
05:28:58,320 --> 05:28:59,320
so 10 base 5 is named for the following
7537
05:29:01,440 --> 05:29:02,440
10 is the transmission speed which is 10
7538
05:29:03,958 --> 05:29:04,958
Meg
7539
05:29:05,160 --> 05:29:06,160
base means the type of signal in his
7540
05:29:07,740 --> 05:29:08,740
baseband and five indicates to the track
7541
05:29:10,378 --> 05:29:11,378
the maximum length of the cable can be
7542
05:29:12,900 --> 05:29:13,900
up to 500 meters
7543
05:29:15,900 --> 05:29:16,900
this is for the segments you could have
7544
05:29:18,000 --> 05:29:19,000
another segment after 500 meters
7545
05:29:20,700 --> 05:29:21,700
and the signal would all have to be a
7546
05:29:23,160 --> 05:29:24,160
replenished
7547
05:29:26,820 --> 05:29:27,820
okay so a thousand Base TX the following
7548
05:29:29,400 --> 05:29:30,400
is true a thousand indicates uh sorry
7549
05:29:32,638 --> 05:29:33,638
100 htx 100 is the speed which is 100
7550
05:29:36,120 --> 05:29:37,120
mag
7551
05:29:37,260 --> 05:29:38,260
base stands for baseband again T
7552
05:29:39,840 --> 05:29:40,840
indicates that the standard is twisted
7553
05:29:42,060 --> 05:29:43,060
pair
7554
05:29:43,320 --> 05:29:44,320
X at the end indicates that the K the
7555
05:29:46,200 --> 05:29:47,200
cable is capable of full duplex
7556
05:29:48,718 --> 05:29:49,718
communication
7557
05:29:52,798 --> 05:29:53,798
10 base 5 real old standard again
7558
05:29:56,100 --> 05:29:57,100
um based on 802.3
7559
05:29:58,500 --> 05:29:59,500
the original standard uses a thick
7560
05:30:01,080 --> 05:30:02,080
coaxial cable as its physical medium it
7561
05:30:03,840 --> 05:30:04,840
was actually called thick net for short
7562
05:30:06,060 --> 05:30:07,060
and you can see the picture of it there
7563
05:30:08,940 --> 05:30:09,940
to actually connecting to the cable use
7564
05:30:10,920 --> 05:30:11,920
these big plastic devices uh called um
7565
05:30:15,240 --> 05:30:16,240
vampire Taps and they're physically
7566
05:30:17,458 --> 05:30:18,458
screwed in to the cable and pierced it
7567
05:30:20,280 --> 05:30:21,280
very awkward to use and hard to
7568
05:30:22,620 --> 05:30:23,620
troubleshoot it ran at 10 Meg
7569
05:30:26,100 --> 05:30:27,100
and either RGA or rg11 it had a little
7570
05:30:29,400 --> 05:30:30,400
resistors on the end to stop the signal
7571
05:30:31,200 --> 05:30:32,200
bouncing off the back of the cable and
7572
05:30:32,760 --> 05:30:33,760
coming back and they ran at 50 ohm RG
7573
05:30:36,600 --> 05:30:37,600
stands for radio government
7574
05:30:39,780 --> 05:30:40,780
standard determ is a type of coaxial
7575
05:30:42,420 --> 05:30:43,420
cables the distance was up to 500 meters
7576
05:30:46,560 --> 05:30:47,560
there were a few pros and cons to using
7577
05:30:48,840 --> 05:30:49,840
thick net
7578
05:30:51,060 --> 05:30:52,060
you have protection against
7579
05:30:53,060 --> 05:30:54,060
electromagnetic interference which can
7580
05:30:55,378 --> 05:30:56,378
seriously degrade your signal
7581
05:30:57,680 --> 05:30:58,680
disadvantage there was loads actually
7582
05:30:59,580 --> 05:31:00,580
difficult to work with very difficult to
7583
05:31:01,620 --> 05:31:02,620
troubleshoot cable was very thick so
7584
05:31:04,500 --> 05:31:05,500
trying to expand it around an office
7585
05:31:06,540 --> 05:31:07,540
without
7586
05:31:07,740 --> 05:31:08,740
and people tripping over or hitting the
7587
05:31:09,780 --> 05:31:10,780
head off them was quite awkward as well
7588
05:31:12,420 --> 05:31:13,420
thin net is based on the 10 base 2
7589
05:31:15,718 --> 05:31:16,718
standard
7590
05:31:17,040 --> 05:31:18,040
so 10 Meg
7591
05:31:18,900 --> 05:31:19,900
um
7592
05:31:20,040 --> 05:31:21,040
baseband and two stands for how long the
7593
05:31:23,218 --> 05:31:24,218
and you could get the connection which
7594
05:31:25,020 --> 05:31:26,020
is 200 meters
7595
05:31:29,340 --> 05:31:30,340
was actually 185 was recommended but you
7596
05:31:31,860 --> 05:31:32,860
couldn't you couldn't ensure to 185 so
7597
05:31:34,320 --> 05:31:35,320
they called it 10 base 2.
7598
05:31:38,458 --> 05:31:39,458
uh being cheaper than thick Navy was
7599
05:31:40,620 --> 05:31:41,620
called cheaper net
7600
05:31:42,180 --> 05:31:43,180
before we had any type of network and we
7601
05:31:44,820 --> 05:31:45,820
used to use floppy disks
7602
05:31:47,040 --> 05:31:48,040
big thick floppy disks not even the
7603
05:31:48,900 --> 05:31:49,900
small ones that you might remember that
7604
05:31:50,760 --> 05:31:51,760
was called sneakinet
7605
05:31:54,298 --> 05:31:55,298
turnbass tea was one of the first modern
7606
05:31:56,340 --> 05:31:57,340
standards introduced in 1990
7607
05:31:59,580 --> 05:32:00,580
it ran over 10 Meg over two pairs of
7608
05:32:02,280 --> 05:32:03,280
twisted uh paired telephone wire
7609
05:32:05,520 --> 05:32:06,520
and it allowed your network to use the
7610
05:32:07,500 --> 05:32:08,500
existing telephone cabling which is
7611
05:32:09,060 --> 05:32:10,060
pretty handy really easy to install
7612
05:32:11,718 --> 05:32:12,718
reduce costs the cable could just be run
7613
05:32:14,760 --> 05:32:15,760
off and you could cut it to whichever
7614
05:32:17,160 --> 05:32:18,160
length you required
7615
05:32:18,958 --> 05:32:19,958
and also obviously you could use a
7616
05:32:20,638 --> 05:32:21,638
network switch which the uh thick and
7617
05:32:23,040 --> 05:32:24,040
thin that couldn't use a switch or hub
7618
05:32:25,560 --> 05:32:26,560
T denotes twisted pair wires
7619
05:32:28,920 --> 05:32:29,920
10 base T is category three cable we
7620
05:32:31,620 --> 05:32:32,620
used to call it cat 3 for short in fact
7621
05:32:34,138 --> 05:32:35,138
every category is is called a cat for um
7622
05:32:37,920 --> 05:32:38,920
short
7623
05:32:40,020 --> 05:32:41,020
High category cables can be used with
7624
05:32:42,180 --> 05:32:43,180
the 10 base T ethernet
7625
05:32:45,120 --> 05:32:46,120
so examples are CAT5 5e 6 6A and so on
7626
05:32:49,798 --> 05:32:50,798
this changes every few months as a new
7627
05:32:51,780 --> 05:32:52,780
category introduced
7628
05:32:53,878 --> 05:32:54,878
High categories of the TP cables have
7629
05:32:56,520 --> 05:32:57,520
higher specifications and they can
7630
05:32:58,440 --> 05:32:59,440
handle higher data transmission speeds
7631
05:33:01,378 --> 05:33:02,378
the term base T supports the maximum
7632
05:33:04,378 --> 05:33:05,378
cable length of 100 meters
7633
05:33:08,458 --> 05:33:09,458
100 Base TX I mentioned earlier
7634
05:33:11,100 --> 05:33:12,100
100 Meg over two pairs of CAT5 twisted
7635
05:33:14,280 --> 05:33:15,280
pair cable in you can get 100 meters
7636
05:33:16,740 --> 05:33:17,740
before you have to terminate the cable
7637
05:33:19,378 --> 05:33:20,378
we normally then go into a switch
7638
05:33:22,138 --> 05:33:23,138
it's called Fast ethernet
7639
05:33:25,080 --> 05:33:26,080
so 100 mag obviously 10 times faster
7640
05:33:28,320 --> 05:33:29,320
than 10 base t
7641
05:33:30,718 --> 05:33:31,718
uh became widely used because of its
7642
05:33:33,600 --> 05:33:34,600
compatibility with 10 base T so imagine
7643
05:33:35,700 --> 05:33:36,700
back in the day you would have your um
7644
05:33:39,660 --> 05:33:40,660
the core of your network running at 100
7645
05:33:42,120 --> 05:33:43,120
Meg and then um unless if you didn't
7646
05:33:45,360 --> 05:33:46,360
have the budget you would have your
7647
05:33:47,040 --> 05:33:48,040
individual PCS connecting at 10 Meg into
7648
05:33:49,980 --> 05:33:50,980
the network switch or hub
7649
05:33:53,340 --> 05:33:54,340
they used a Cat5 cables a lot easier to
7650
05:33:56,280 --> 05:33:57,280
upgrade because it used the same Cable
7651
05:33:58,920 --> 05:33:59,920
in principles and same pin outs
7652
05:34:01,500 --> 05:34:02,500
and determination
7653
05:34:04,138 --> 05:34:05,138
100 base FX f is usually designates
7654
05:34:07,740 --> 05:34:08,740
fiber optic
7655
05:34:09,980 --> 05:34:10,980
fiber standard for 100 Meg ethernet is
7656
05:34:12,900 --> 05:34:13,900
100 base FX
7657
05:34:16,500 --> 05:34:17,500
so this is a
7658
05:34:18,560 --> 05:34:19,560
802.3 u specification
7659
05:34:22,320 --> 05:34:23,320
it's 100 Meg ethernet over two
7660
05:34:24,240 --> 05:34:25,240
multi-mode Optical fibers
7661
05:34:27,840 --> 05:34:28,840
one's used for the transmission and ones
7662
05:34:29,878 --> 05:34:30,878
used for the receiver as and designated
7663
05:34:32,218 --> 05:34:33,218
in the diagram there
7664
05:34:35,540 --> 05:34:36,540
the 100 base FX standard supports the
7665
05:34:38,280 --> 05:34:39,280
maximum cable length of 400 meters in
7666
05:34:41,100 --> 05:34:42,100
half duplex mode
7667
05:34:43,080 --> 05:34:44,080
half duplex is pretty old-fashioned now
7668
05:34:45,240 --> 05:34:46,240
to be honest
7669
05:34:46,740 --> 05:34:47,740
or in full duplex mode
7670
05:34:48,900 --> 05:34:49,900
which means you can send and receive at
7671
05:34:50,458 --> 05:34:51,458
the same time then up to two kilometers
7672
05:34:54,480 --> 05:34:55,480
half duplex mode as well just so
7673
05:34:56,878 --> 05:34:57,878
basically it's like a walkie-talk here
7674
05:34:58,620 --> 05:34:59,620
device can either send or receive data
7675
05:35:00,600 --> 05:35:01,600
at a given time but it can't do both
7676
05:35:03,298 --> 05:35:04,298
full duplexy can do both so it's like
7677
05:35:05,940 --> 05:35:06,940
having a telephone conversation
7678
05:35:08,218 --> 05:35:09,218
a thousand base T now we're talking 10
7679
05:35:11,340 --> 05:35:12,340
times faster than a hundred
7680
05:35:13,798 --> 05:35:14,798
it's a IEEE 802.3 a b specification it's
7681
05:35:19,860 --> 05:35:20,860
a thousand megabit per second ethernet
7682
05:35:21,958 --> 05:35:22,958
Network uses four pairs of CAT5 cable or
7683
05:35:26,040 --> 05:35:27,040
better
7684
05:35:26,878 --> 05:35:27,878
and speak to your cabling provider to um
7685
05:35:30,480 --> 05:35:31,480
find out what cable you can use minimum
7686
05:35:33,120 --> 05:35:34,120
standards
7687
05:35:35,100 --> 05:35:36,100
100 meter length of cable
7688
05:35:38,638 --> 05:35:39,638
it's um referred to as gigabit Ethernet
7689
05:35:41,700 --> 05:35:42,700
1000 bits
7690
05:35:43,260 --> 05:35:44,260
that easy to install runs on CAT5
7691
05:35:46,620 --> 05:35:47,620
and inexpensive cables
7692
05:35:50,040 --> 05:35:51,040
as an example of a CAT5 cable which I'm
7693
05:35:52,620 --> 05:35:53,620
sure you've seen many times even if
7694
05:35:54,600 --> 05:35:55,600
you've got a home computer
7695
05:35:57,780 --> 05:35:58,780
so the Cat5 cables are four pairs of
7696
05:35:59,878 --> 05:36:00,878
twist uh four pairs of Twisted wire
7697
05:36:02,280 --> 05:36:03,280
which is eight individual strands
7698
05:36:05,700 --> 05:36:06,700
the 10 and 100 base T only uses two
7699
05:36:08,760 --> 05:36:09,760
pairs
7700
05:36:09,958 --> 05:36:10,958
all four pairs are used by the EM
7701
05:36:12,420 --> 05:36:13,420
thousand base t
7702
05:36:15,240 --> 05:36:16,240
popular gigabit Ethernet and the
7703
05:36:18,180 --> 05:36:19,180
Thousand base T is the most widely used
7704
05:36:19,980 --> 05:36:20,980
version
7705
05:36:21,660 --> 05:36:22,660
you've got the a223 standard that
7706
05:36:23,820 --> 05:36:24,820
specifies other versions of gigabit
7707
05:36:25,798 --> 05:36:26,798
Ethernet here are some of your options
7708
05:36:29,100 --> 05:36:30,100
um thousand Bay CX LS LX
7709
05:36:32,940 --> 05:36:33,940
SX
7710
05:36:35,218 --> 05:36:36,218
uh you need to know some of this
7711
05:36:37,980 --> 05:36:38,980
information but I think one of the
7712
05:36:39,600 --> 05:36:40,600
questions they could ask is which one of
7713
05:36:41,340 --> 05:36:42,340
them is
7714
05:36:43,138 --> 05:36:44,138
um fiber optic and the answer is LX it's
7715
05:36:46,680 --> 05:36:47,680
a question I've seen before I think I
7716
05:36:48,900 --> 05:36:49,900
was actually asked in a Cisco exam not
7717
05:36:51,600 --> 05:36:52,600
um uh CompTIA Network plus but good to
7718
05:36:54,718 --> 05:36:55,718
know anyway
7719
05:36:56,940 --> 05:36:57,940
so five kilometers to 550 meters
7720
05:37:00,240 --> 05:37:01,240
depending if it's single or multi-mode
7721
05:37:03,540 --> 05:37:04,540
and SX is implemented over multi-mode
7722
05:37:06,120 --> 05:37:07,120
fiber as well so um LX and SX
7723
05:37:11,100 --> 05:37:12,100
1000 Base TX is gigabit over Cat6
7724
05:37:14,520 --> 05:37:15,520
cabling
7725
05:37:16,500 --> 05:37:17,500
supports a maximum cable length of 100
7726
05:37:19,320 --> 05:37:20,320
meters
7727
05:37:21,020 --> 05:37:22,020
uh uses only two pairs of wires for the
7728
05:37:24,840 --> 05:37:25,840
data transmission
7729
05:37:27,120 --> 05:37:28,120
now the Thousand Base TX you don't
7730
05:37:29,160 --> 05:37:30,160
really see much anymore is a bit of a
7731
05:37:30,780 --> 05:37:31,780
commercial failure
7732
05:37:32,280 --> 05:37:33,280
mainly because of the Thousand base T
7733
05:37:34,620 --> 05:37:35,620
the cost was so affordable you had to
7734
05:37:37,138 --> 05:37:38,138
upgrade all of your cables from CAT5 or
7735
05:37:39,900 --> 05:37:40,900
Cat5e to Cat6 which is a lot of
7736
05:37:42,718 --> 05:37:43,718
inconvenience and expensive companies
7737
05:37:44,878 --> 05:37:45,878
and downtime
7738
05:37:46,620 --> 05:37:47,620
because of your all your core devices
7739
05:37:48,360 --> 05:37:49,360
would need the connections would need to
7740
05:37:50,280 --> 05:37:51,280
be um changed as well normally have to
7741
05:37:52,560 --> 05:37:53,560
schedule downtime
7742
05:37:55,200 --> 05:37:56,200
um for this
7743
05:37:57,020 --> 05:37:58,020
10 gigabyte 10g base t 10 times faster
7744
05:38:01,680 --> 05:38:02,680
than a thousand base T ethernet operates
7745
05:38:04,798 --> 05:38:05,798
at 10 gig
7746
05:38:06,480 --> 05:38:07,480
and it's an 802.3 a n specification four
7747
05:38:11,280 --> 05:38:12,280
pairs of Cat6 a cable or higher
7748
05:38:15,000 --> 05:38:16,000
100 meters maximum
7749
05:38:18,180 --> 05:38:19,180
it's an augmented version of category
7750
05:38:20,878 --> 05:38:21,878
six which you can see 6A isn't the same
7751
05:38:24,298 --> 05:38:25,298
as six
7752
05:38:25,920 --> 05:38:26,920
and frequency is at 500 megahertz
7753
05:38:29,878 --> 05:38:30,878
next standard is 10gbase Sr this is
7754
05:38:33,420 --> 05:38:34,420
gigabit Ethernet over Fiber Optic Cables
7755
05:38:35,878 --> 05:38:36,878
I don't know why they don't just put a f
7756
05:38:38,400 --> 05:38:39,400
in all of the fiber specifications it's
7757
05:38:40,860 --> 05:38:41,860
a little bit annoying to be honest
7758
05:38:43,400 --> 05:38:44,400
802.3 specification
7759
05:38:46,378 --> 05:38:47,378
is 10 gig ethernet over multi-mode fiber
7760
05:38:49,080 --> 05:38:50,080
the SR stands for short range
7761
05:38:52,620 --> 05:38:53,620
at the cable length is 300 meters so you
7762
05:38:54,958 --> 05:38:55,958
only need to make a note of all of these
7763
05:38:56,760 --> 05:38:57,760
in case they
7764
05:38:58,080 --> 05:38:59,080
for some reason want you to
7765
05:39:00,180 --> 05:39:01,180
um remember this generally most of us
7766
05:39:02,340 --> 05:39:03,340
will just look speak to the sales
7767
05:39:03,900 --> 05:39:04,900
advisor or just look on the um online or
7768
05:39:07,560 --> 05:39:08,560
some documentation
7769
05:39:09,718 --> 05:39:10,718
10 gbase er
7770
05:39:14,840 --> 05:39:15,840
802.3 AE a gigabit over single mode
7771
05:39:18,900 --> 05:39:19,900
fiber optic cabling ER stands for
7772
05:39:21,360 --> 05:39:22,360
extended range you got up to full of 40
7773
05:39:24,480 --> 05:39:25,480
kilometers which is a quite a nice
7774
05:39:26,520 --> 05:39:27,520
distance amazing distance in fact
7775
05:39:30,780 --> 05:39:31,780
uh SW
7776
05:39:32,820 --> 05:39:33,820
that was designed for use over a
7777
05:39:34,980 --> 05:39:35,980
particular type of Technology sonnet or
7778
05:39:38,040 --> 05:39:39,040
sdh
7779
05:39:42,060 --> 05:39:43,060
again multi-mode fiber 300 meters again
7780
05:39:45,660 --> 05:39:46,660
all right so we've covered a few of the
7781
05:39:47,820 --> 05:39:48,820
basics of ethernet here the history the
7782
05:39:50,100 --> 05:39:51,100
name the standards uh the oee what they
7783
05:39:54,480 --> 05:39:55,480
do in brief
7784
05:39:55,980 --> 05:39:56,980
I recommend you have a look in your own
7785
05:39:58,138 --> 05:39:59,138
time at Wikipedia
7786
05:39:59,940 --> 05:40:00,940
the popularity which is nearly always
7787
05:40:01,920 --> 05:40:02,920
the fact it's the standards are free to
7788
05:40:03,660 --> 05:40:04,660
use and it's affordable and everyone
7789
05:40:05,820 --> 05:40:06,820
else is using the same standards
7790
05:40:08,040 --> 05:40:09,040
baseband the Broadband the naming
7791
05:40:10,378 --> 05:40:11,378
conventions and then some of the
7792
05:40:11,940 --> 05:40:12,940
different standards here
7793
05:40:13,860 --> 05:40:14,860
you'll need to know the different
7794
05:40:15,180 --> 05:40:16,180
standards which uses a single and
7795
05:40:17,340 --> 05:40:18,340
multi-mode how long um you can have a
7796
05:40:19,980 --> 05:40:20,980
segment that lengths and that kind of
7797
05:40:21,660 --> 05:40:22,660
thing
7798
05:40:22,378 --> 05:40:23,378
all right so that's the end of the
7799
05:40:23,638 --> 05:40:24,638
presentation thanks for watching
7800
05:40:30,430 --> 05:40:31,430
[Music]
7801
05:40:51,180 --> 05:40:52,180
Network infrastructure and Design
7802
05:40:53,480 --> 05:40:54,480
Network models the OSI model
7803
05:40:57,240 --> 05:40:58,240
so we're going to discuss two different
7804
05:40:58,798 --> 05:40:59,798
models coming up here and the first
7805
05:41:00,540 --> 05:41:01,540
model I want to talk about is the OSI
7806
05:41:02,638 --> 05:41:03,638
model in this module now from this
7807
05:41:04,980 --> 05:41:05,980
lesson you're going to have a thorough
7808
05:41:06,480 --> 05:41:07,480
understanding of each of the layers in
7809
05:41:09,718 --> 05:41:10,718
this module and there are seven of them
7810
05:41:11,900 --> 05:41:12,900
and we're also going to talk about how
7811
05:41:14,340 --> 05:41:15,340
those layers communicate some of the
7812
05:41:16,620 --> 05:41:17,620
devices that operate at specific layers
7813
05:41:19,200 --> 05:41:20,200
specifically layers one through three
7814
05:41:22,798 --> 05:41:23,798
and some of the protocols that operate
7815
05:41:25,020 --> 05:41:26,020
on some of these layers as well
7816
05:41:26,400 --> 05:41:27,400
specifically the upper layers we're also
7817
05:41:28,740 --> 05:41:29,740
going to have a better understanding of
7818
05:41:29,700 --> 05:41:30,700
what the OSI model is and why we use a
7819
05:41:32,700 --> 05:41:33,700
layered approach
7820
05:41:34,200 --> 05:41:35,200
so this model is going to teach us
7821
05:41:36,298 --> 05:41:37,298
everything we need to know about the OSI
7822
05:41:39,240 --> 05:41:40,240
model we're going to begin by explaining
7823
05:41:41,400 --> 05:41:42,400
exactly what the OSI model is and what
7824
05:41:44,040 --> 05:41:45,040
the purpose of it is as well then we're
7825
05:41:46,500 --> 05:41:47,500
going to go through and explain each
7826
05:41:47,820 --> 05:41:48,820
layer from layer 1 the physical layer to
7827
05:41:51,298 --> 05:41:52,298
layer 2 the data link layer later three
7828
05:41:54,420 --> 05:41:55,420
the network layer layer 4 transport
7829
05:41:57,840 --> 05:41:58,840
layer layer 5 the session layer layer 6
7830
05:42:02,100 --> 05:42:03,100
the presentation layer and finally layer
7831
05:42:04,740 --> 05:42:05,740
7 the application layer we're also going
7832
05:42:07,620 --> 05:42:08,620
to discuss some of the protocols and
7833
05:42:09,660 --> 05:42:10,660
devices that operate at each of these
7834
05:42:12,420 --> 05:42:13,420
layers and we're also going to
7835
05:42:14,638 --> 05:42:15,638
understand how communication begins and
7836
05:42:17,580 --> 05:42:18,580
ends through these layers now early back
7837
05:42:21,780 --> 05:42:22,780
in the 1980s late 70s when networking
7838
05:42:24,958 --> 05:42:25,958
communication between devices which a
7839
05:42:27,060 --> 05:42:28,060
lot simpler a lot of brilliant
7840
05:42:28,740 --> 05:42:29,740
individuals from the iso organization
7841
05:42:31,200 --> 05:42:32,200
we've seen previously or the
7842
05:42:33,180 --> 05:42:34,180
International Organization for
7843
05:42:34,740 --> 05:42:35,740
standardization came together and they
7844
05:42:36,900 --> 05:42:37,900
came up with a a way to outline
7845
05:42:39,680 --> 05:42:40,680
standardize and characterize the
7846
05:42:43,020 --> 05:42:44,020
functions of a communication system or
7847
05:42:46,260 --> 05:42:47,260
the methods by which computers are going
7848
05:42:48,480 --> 05:42:49,480
to communicate in a network environment
7849
05:42:50,878 --> 05:42:51,878
so they came up with this OSI model and
7850
05:42:53,700 --> 05:42:54,700
I love it because I know the iso made
7851
05:42:56,218 --> 05:42:57,218
the OSI and they did this in term of
7852
05:42:59,100 --> 05:43:00,100
abstract layers so what we mean by these
7853
05:43:02,638 --> 05:43:03,638
abstract layers and here they are again
7854
05:43:04,500 --> 05:43:05,500
from the top down application press
7855
05:43:06,840 --> 05:43:07,840
presentation session transport layer
7856
05:43:09,180 --> 05:43:10,180
data link physical and just so we don't
7857
05:43:11,160 --> 05:43:12,160
get confused the first layer is actually
7858
05:43:14,160 --> 05:43:15,160
here at the bottom and the last layer is
7859
05:43:16,500 --> 05:43:17,500
here at the top and that and viewing
7860
05:43:18,958 --> 05:43:19,958
this we call this a top
7861
05:43:21,600 --> 05:43:22,600
down approach as opposed to a bottom-up
7862
05:43:24,180 --> 05:43:25,180
approach
7863
05:43:26,940 --> 05:43:27,940
and these
7864
05:43:28,378 --> 05:43:29,378
abstract layers outline the functions of
7865
05:43:31,440 --> 05:43:32,440
the communications process but they hide
7866
05:43:34,020 --> 05:43:35,020
exactly specifically how they're
7867
05:43:35,820 --> 05:43:36,820
implemented in each layer in other words
7868
05:43:38,218 --> 05:43:39,218
this really attempts to simplify and
7869
05:43:41,160 --> 05:43:42,160
sometimes oversimplify exactly how
7870
05:43:43,378 --> 05:43:44,378
everything in the network is
7871
05:43:44,700 --> 05:43:45,700
communicated so let's say that we want
7872
05:43:47,940 --> 05:43:48,940
to establish a highway more so we really
7873
05:43:50,700 --> 05:43:51,700
want to build a brand new type of
7874
05:43:52,620 --> 05:43:53,620
vehicle designed specifically to be
7875
05:43:54,840 --> 05:43:55,840
driven on this very specific Highway and
7876
05:43:58,200 --> 05:43:59,200
we're going to have to do it from the
7877
05:43:59,638 --> 05:44:00,638
ground up so let's call this vehicle a
7878
05:44:02,520 --> 05:44:03,520
bus
7879
05:44:03,420 --> 05:44:04,420
not only do we want this bus to be able
7880
05:44:06,000 --> 05:44:07,000
to run on any of the existing highways
7881
05:44:08,218 --> 05:44:09,218
or they're out there but we also want
7882
05:44:10,200 --> 05:44:11,200
the bus to be able to use the already
7883
05:44:11,940 --> 05:44:12,940
existing bus stations as well so in
7884
05:44:14,760 --> 05:44:15,760
order to do this we need to understand
7885
05:44:16,680 --> 05:44:17,680
exactly what we already have meaning
7886
05:44:19,200 --> 05:44:20,200
what the standards are already in place
7887
05:44:21,298 --> 05:44:22,298
for a highway we also need to know
7888
05:44:23,878 --> 05:44:24,878
everything about bus stations and
7889
05:44:26,218 --> 05:44:27,218
everything about the infrastructure of
7890
05:44:28,260 --> 05:44:29,260
the highway system that already exists
7891
05:44:30,320 --> 05:44:31,320
regardless of whether we actually have
7892
05:44:33,058 --> 05:44:34,058
to build the highway
7893
05:44:34,798 --> 05:44:35,798
we still need to understand everything
7894
05:44:36,958 --> 05:44:37,958
that relates to highways and their
7895
05:44:38,940 --> 05:44:39,940
designs uh to the materials the
7896
05:44:41,458 --> 05:44:42,458
limitations and so on so this way when
7897
05:44:44,400 --> 05:44:45,400
we're designing our brand new bus we can
7898
05:44:46,680 --> 05:44:47,680
ensure that it still can drive and
7899
05:44:48,600 --> 05:44:49,600
operate on older highways not to mention
7900
05:44:50,760 --> 05:44:51,760
new highways and that our bus is going
7901
05:44:53,400 --> 05:44:54,400
to interact uh properly with the other
7902
05:44:56,100 --> 05:44:57,100
buses and other vehicles that are on the
7903
05:44:58,320 --> 05:44:59,320
road the other benefit here is if I'm
7904
05:45:00,780 --> 05:45:01,780
designing this bus and I break it down
7905
05:45:02,760 --> 05:45:03,760
into different layers seven of them I
7906
05:45:05,520 --> 05:45:06,520
only have to worry about one part for
7907
05:45:07,860 --> 05:45:08,860
instance there might be someone who is
7908
05:45:10,020 --> 05:45:11,020
responsible for say the wheels and there
7909
05:45:12,718 --> 05:45:13,718
might be someone else who's responsible
7910
05:45:15,000 --> 05:45:16,000
for uh say the body and there might be
7911
05:45:19,020 --> 05:45:20,020
someone else who's responsible for the
7912
05:45:21,000 --> 05:45:22,000
highway and someone else who's
7913
05:45:22,260 --> 05:45:23,260
responsible for the bus stop and so on
7914
05:45:25,020 --> 05:45:26,020
and so forth this way I can fragment
7915
05:45:27,058 --> 05:45:28,058
everything out and give everyone
7916
05:45:28,500 --> 05:45:29,500
specific jobs and if a problem occurs
7917
05:45:31,080 --> 05:45:32,080
with the bus then I can go to the
7918
05:45:33,660 --> 05:45:34,660
specific person who with whom who is
7919
05:45:36,540 --> 05:45:37,540
most familiar with that section or that
7920
05:45:38,520 --> 05:45:39,520
layer this is the benefit to a layered
7921
05:45:40,860 --> 05:45:41,860
approach to creating something
7922
05:45:42,660 --> 05:45:43,660
so that being said let's talk about the
7923
05:45:44,760 --> 05:45:45,760
very first layer layer one
7924
05:45:46,740 --> 05:45:47,740
so layer one is the physical layer the
7925
05:45:49,620 --> 05:45:50,620
this is the actual physical media the
7926
05:45:52,080 --> 05:45:53,080
cables the wires this is the means by
7927
05:45:54,780 --> 05:45:55,780
which the bits go from one point to
7928
05:45:57,840 --> 05:45:58,840
another so for the actual cable uh the
7929
05:46:02,700 --> 05:46:03,700
infrared connection the radio frequency
7930
05:46:05,100 --> 05:46:06,100
even Wi-Fi all of these reference the
7931
05:46:08,520 --> 05:46:09,520
layer or the pathway that the data is
7932
05:46:10,620 --> 05:46:11,620
going to take so to take a look in this
7933
05:46:12,718 --> 05:46:13,718
in the way that we were talking about it
7934
05:46:14,100 --> 05:46:15,100
with our bus and our Highway setting if
7935
05:46:16,920 --> 05:46:17,920
our main concern is building our buses
7936
05:46:19,558 --> 05:46:20,558
we need to look at all of the other
7937
05:46:21,540 --> 05:46:22,540
vehicles on the road we need to
7938
05:46:23,520 --> 05:46:24,520
understand their size their shape other
7939
05:46:26,600 --> 05:46:27,600
characteristics and so on so that way we
7940
05:46:29,820 --> 05:46:30,820
understand how our bus can use the same
7941
05:46:32,580 --> 05:46:33,580
tracks the other vehicles are using so
7942
05:46:35,218 --> 05:46:36,218
here on layer one we have the path the
7943
05:46:37,558 --> 05:46:38,558
road used for communication again this
7944
05:46:40,620 --> 05:46:41,620
is the wire the Bluetooth fiber copper
7945
05:46:44,280 --> 05:46:45,280
the Wi-Fi whatever means there is that
7946
05:46:47,400 --> 05:46:48,400
physically the bits the ones and zeros
7947
05:46:49,558 --> 05:46:50,558
rows are going over this media so the
7948
05:46:54,240 --> 05:46:55,240
terminology for the information is
7949
05:46:56,218 --> 05:46:57,218
considered simply the bits because we're
7950
05:46:58,260 --> 05:46:59,260
actually transmitting the raw one and
7951
05:47:00,058 --> 05:47:01,058
ones and zeros we're not dealing here
7952
05:47:02,580 --> 05:47:03,580
with what the information is we're
7953
05:47:04,860 --> 05:47:05,860
dealing with it at the most Electrical
7954
05:47:07,100 --> 05:47:08,100
uh basic sort of
7955
05:47:10,378 --> 05:47:11,378
standpoint so this is simply the mid the
7956
05:47:13,260 --> 05:47:14,260
median this is called physical and as
7957
05:47:15,480 --> 05:47:16,480
you can imagine this is also the very
7958
05:47:18,000 --> 05:47:19,000
first place that data is going to enter
7959
05:47:20,340 --> 05:47:21,340
into the computer right it goes over the
7960
05:47:22,680 --> 05:47:23,680
chord and into a nick
7961
05:47:24,600 --> 05:47:25,600
all right now what happens then
7962
05:47:27,298 --> 05:47:28,298
well then we get to Layer Two which is
7963
05:47:29,520 --> 05:47:30,520
called the data link layer an easy way
7964
05:47:32,040 --> 05:47:33,040
to remember that the layer 2 is data
7965
05:47:34,320 --> 05:47:35,320
link is because it's the only one that
7966
05:47:36,180 --> 05:47:37,180
has two words it also has and this is
7967
05:47:39,900 --> 05:47:40,900
not as important uh for
7968
05:47:42,660 --> 05:47:43,660
this uh for the network plus exam but
7969
05:47:45,180 --> 05:47:46,180
it's still good to know there are two
7970
05:47:46,558 --> 05:47:47,558
what we call sub-layers the max sub
7971
05:47:49,200 --> 05:47:50,200
layer and the LLC sub layer
7972
05:47:52,200 --> 05:47:53,200
this layer in total and so these two
7973
05:47:55,500 --> 05:47:56,500
make up
7974
05:47:56,638 --> 05:47:57,638
this data link layer and this layer as a
7975
05:47:59,878 --> 05:48:00,878
whole is responsible for allowing
7976
05:48:01,558 --> 05:48:02,558
devices to share the same medium the
7977
05:48:04,980 --> 05:48:05,980
medium being the physical layer so here
7978
05:48:07,798 --> 05:48:08,798
we see a few things happening first we
7979
05:48:10,080 --> 05:48:11,080
see a certain level of error correction
7980
05:48:13,680 --> 05:48:14,680
and error detection on the physical
7981
05:48:16,020 --> 05:48:17,020
layer we're going to see this a little
7982
05:48:17,400 --> 05:48:18,400
more on later layers as well
7983
05:48:19,260 --> 05:48:20,260
also and probably more important we see
7984
05:48:22,440 --> 05:48:23,440
access control which I've denoted here
7985
05:48:25,680 --> 05:48:26,680
and I'll get to this in a minute by the
7986
05:48:27,660 --> 05:48:28,660
stop light
7987
05:48:28,680 --> 05:48:29,680
so this function is performed by this
7988
05:48:31,558 --> 05:48:32,558
Max sub layer again I wouldn't worry too
7989
05:48:33,420 --> 05:48:34,420
much about that but the most important
7990
05:48:35,458 --> 05:48:36,458
thing here is that we have physical
7991
05:48:37,520 --> 05:48:38,520
addressing or the MAC address so
7992
05:48:40,620 --> 05:48:41,620
anything that looks at Mac addressing
7993
05:48:43,740 --> 05:48:44,740
and by the way Mac addressing is oddly
7994
05:48:46,200 --> 05:48:47,200
enough performed
7995
05:48:48,000 --> 05:48:49,000
by the LLC layer
7996
05:48:50,878 --> 05:48:51,878
allows a device to look at a certain
7997
05:48:52,798 --> 05:48:53,798
extra layer of information so whereas
7998
05:48:57,540 --> 05:48:58,540
with layer one we saw physical if you
7999
05:48:59,400 --> 05:49:00,400
remember we talked about hubs hubs just
8000
05:49:01,798 --> 05:49:02,798
forward bits they don't look at the bits
8001
05:49:03,600 --> 05:49:04,600
so they're going to operate at layer one
8002
05:49:05,218 --> 05:49:06,218
here at Layer Two we start dealing with
8003
05:49:07,680 --> 05:49:08,680
Mac addresses as a result this is where
8004
05:49:10,680 --> 05:49:11,680
devices like switches are found and
8005
05:49:14,700 --> 05:49:15,700
that's why switches are often called
8006
05:49:17,120 --> 05:49:18,120
layer 2 devices
8007
05:49:19,860 --> 05:49:20,860
there are more advanced types of
8008
05:49:21,718 --> 05:49:22,718
switches but I want you to remember
8009
05:49:22,920 --> 05:49:23,920
again a switch is a layer 2 device now
8010
05:49:27,718 --> 05:49:28,718
if we look at this in a slightly
8011
05:49:29,280 --> 05:49:30,280
different way here's where we have to be
8012
05:49:32,218 --> 05:49:33,218
able to have access control on our
8013
05:49:33,958 --> 05:49:34,958
highway so this is where we have to be
8014
05:49:36,120 --> 05:49:37,120
able to have uh proper on-ramps that are
8015
05:49:39,298 --> 05:49:40,298
only going to allow authorized vehicles
8016
05:49:41,340 --> 05:49:42,340
to enter onto the road and we also need
8017
05:49:43,740 --> 05:49:44,740
to establish standards for how the road
8018
05:49:45,718 --> 05:49:46,718
is going to be used by everyone perhaps
8019
05:49:48,958 --> 05:49:49,958
with signs and here we also remember
8020
05:49:51,058 --> 05:49:52,058
this is where we establish how everyone
8021
05:49:52,620 --> 05:49:53,620
is going to share the road who's going
8022
05:49:54,600 --> 05:49:55,600
to access the road and a certain level
8023
05:49:57,718 --> 05:49:58,718
of checking for damage on the highway
8024
05:49:59,638 --> 05:50:00,638
and vehicles for instance people sort of
8025
05:50:02,280 --> 05:50:03,280
going on and making sure there aren't
8026
05:50:03,958 --> 05:50:04,958
potholes in this layer we refer to the
8027
05:50:07,020 --> 05:50:08,020
data as frames of data because they're
8028
05:50:10,260 --> 05:50:11,260
beginning to get framed we're no longer
8029
05:50:12,120 --> 05:50:13,120
just dealing with the ones and zeros
8030
05:50:14,040 --> 05:50:15,040
we're dealing with them in a frame or in
8031
05:50:18,000 --> 05:50:19,000
a uh sort of larger context now the next
8032
05:50:21,958 --> 05:50:22,958
layer is layer three or the network
8033
05:50:24,840 --> 05:50:25,840
layer here's where a really a lot of
8034
05:50:27,180 --> 05:50:28,180
exciting stuff happens okay first the
8035
05:50:30,180 --> 05:50:31,180
third layer is different from the second
8036
05:50:31,920 --> 05:50:32,920
layer in that the data link layer
8037
05:50:34,820 --> 05:50:35,820
transfers data between devices that are
8038
05:50:37,680 --> 05:50:38,680
within the same network okay so if you
8039
05:50:40,860 --> 05:50:41,860
remember we talked with dealing with
8040
05:50:42,298 --> 05:50:43,298
switches switches only deal with devices
8041
05:50:44,280 --> 05:50:45,280
on the same network but here on layer
8042
05:50:47,100 --> 05:50:48,100
three the network layer can allow us to
8043
05:50:49,980 --> 05:50:50,980
transfer data to and from devices that
8044
05:50:52,620 --> 05:50:53,620
are on different networks it does this
8045
05:50:55,320 --> 05:50:56,320
by a specific kind of addressing
8046
05:50:58,320 --> 05:50:59,320
specifically
8047
05:50:59,700 --> 05:51:00,700
IP addressing and when we deal with IP
8048
05:51:02,700 --> 05:51:03,700
addressing or the Internet Protocol
8049
05:51:07,320 --> 05:51:08,320
we allow what's called routing
8050
05:51:10,320 --> 05:51:11,320
so the main job of the network layer is
8051
05:51:12,900 --> 05:51:13,900
really about this routing it's about
8052
05:51:14,940 --> 05:51:15,940
routing and routers so knowing this and
8053
05:51:17,878 --> 05:51:18,878
that IP addresses are used for routing
8054
05:51:19,920 --> 05:51:20,920
we come to the conclusion that the kinds
8055
05:51:22,320 --> 05:51:23,320
of devices we're really going to find in
8056
05:51:23,820 --> 05:51:24,820
this layer
8057
05:51:24,958 --> 05:51:25,958
are routers so routers are what we call
8058
05:51:28,378 --> 05:51:29,378
layer 3 devices and that's you're going
8059
05:51:30,600 --> 05:51:31,600
to see on the test now for the
8060
05:51:32,940 --> 05:51:33,940
information to actually reach the
8061
05:51:35,878 --> 05:51:36,878
destination this IP address has to be
8062
05:51:38,820 --> 05:51:39,820
mapped
8063
05:51:40,080 --> 05:51:41,080
to a physical address on layer 2.
8064
05:51:44,218 --> 05:51:45,218
so the protocol that does this is called
8065
05:51:47,218 --> 05:51:48,218
arp
8066
05:51:48,600 --> 05:51:49,600
what ARP does
8067
05:51:51,240 --> 05:51:52,240
is it Maps
8068
05:51:54,840 --> 05:51:55,840
for better for a lack of a better way of
8069
05:51:57,000 --> 05:51:58,000
describing it Maps Mac addresses
8070
05:52:01,138 --> 05:52:02,138
to IP addresses by the way ARP stands
8071
05:52:04,500 --> 05:52:05,500
for address
8072
05:52:12,180 --> 05:52:13,180
resolution
8073
05:52:15,660 --> 05:52:16,660
protocol
8074
05:52:19,860 --> 05:52:20,860
this protocol actually operates slightly
8075
05:52:23,580 --> 05:52:24,580
on the network layer and slightly on the
8076
05:52:25,320 --> 05:52:26,320
data link layer because obviously it's
8077
05:52:27,180 --> 05:52:28,180
dealing with Mac addresses and IP
8078
05:52:29,340 --> 05:52:30,340
addresses
8079
05:52:33,900 --> 05:52:34,900
now it's important that you consider
8080
05:52:35,400 --> 05:52:36,400
that remember we talked about
8081
05:52:37,500 --> 05:52:38,500
UDP
8082
05:52:38,638 --> 05:52:39,638
versus TCP
8083
05:52:41,638 --> 05:52:42,638
UDP being
8084
05:52:45,000 --> 05:52:46,000
connection less and TCP being connection
8085
05:52:51,860 --> 05:52:52,860
oriented that's when we're dealing with
8086
05:52:54,298 --> 05:52:55,298
ports and we'll talk about that more we
8087
05:52:55,980 --> 05:52:56,980
talked about that in a plus and we'll
8088
05:52:57,360 --> 05:52:58,360
talk about that a little more later well
8089
05:52:59,400 --> 05:53:00,400
everything in the network layer is
8090
05:53:01,558 --> 05:53:02,558
connection less
8091
05:53:04,020 --> 05:53:05,020
this means that it manages the transfer
8092
05:53:07,260 --> 05:53:08,260
of data in a connection less uh mode it
8093
05:53:11,280 --> 05:53:12,280
just sends the data but it's not going
8094
05:53:12,900 --> 05:53:13,900
to wait for a reply to ensure it got to
8095
05:53:15,120 --> 05:53:16,120
its destination this means we're sort of
8096
05:53:17,458 --> 05:53:18,458
using a best effort here this is like
8097
05:53:21,360 --> 05:53:22,360
dropping something in the mail and just
8098
05:53:23,160 --> 05:53:24,160
hoping it gets there we're not using
8099
05:53:24,660 --> 05:53:25,660
certified mail at all on layer 3 the
8100
05:53:28,860 --> 05:53:29,860
information remember Layer Two we had
8101
05:53:30,900 --> 05:53:31,900
frames well now we have something called
8102
05:53:33,000 --> 05:53:34,000
datagrams
8103
05:53:35,940 --> 05:53:36,940
so this is now we're moving up right we
8104
05:53:38,760 --> 05:53:39,760
had frames now the frames are packaged
8105
05:53:40,500 --> 05:53:41,500
into datagrams so if we keep with our
8106
05:53:43,138 --> 05:53:44,138
method of talking about the bus metaphor
8107
05:53:45,058 --> 05:53:46,058
okay
8108
05:53:47,100 --> 05:53:48,100
from the third layer up we're going to
8109
05:53:49,260 --> 05:53:50,260
concentrate on the bus itself so we've
8110
05:53:51,900 --> 05:53:52,900
been talking about the road right we
8111
05:53:54,058 --> 05:53:55,058
talked about the road itself the
8112
05:53:55,860 --> 05:53:56,860
physical layer and then we talked about
8113
05:53:57,058 --> 05:53:58,058
how people are going to share that road
8114
05:53:58,798 --> 05:53:59,798
which is Layer Two
8115
05:54:01,378 --> 05:54:02,378
data link layer now layer 3 the network
8116
05:54:04,020 --> 05:54:05,020
layer this is the bus itself layer 3
8117
05:54:07,020 --> 05:54:08,020
through 7 concentrates on the processes
8118
05:54:09,780 --> 05:54:10,780
that affect this container in our case
8119
05:54:13,020 --> 05:54:14,020
the bus since we're basically designing
8120
05:54:15,780 --> 05:54:16,780
our bus this layer is determining the
8121
05:54:17,878 --> 05:54:18,878
best path that our data is going to take
8122
05:54:20,580 --> 05:54:21,580
so in a manner of speaking this is like
8123
05:54:22,680 --> 05:54:23,680
the bus driver on a specific route who's
8124
05:54:25,558 --> 05:54:26,558
going to constantly updating us with
8125
05:54:27,480 --> 05:54:28,480
routing information so it's saying
8126
05:54:29,638 --> 05:54:30,638
here's our first destination here's our
8127
05:54:31,260 --> 05:54:32,260
second destination here's our third
8128
05:54:32,820 --> 05:54:33,820
destination just in case a route is
8129
05:54:35,580 --> 05:54:36,580
blocked or if there's a faster or better
8130
05:54:37,320 --> 05:54:38,320
route available layer 3 is where those
8131
05:54:40,138 --> 05:54:41,138
Protocols are going to operate to find
8132
05:54:42,180 --> 05:54:43,180
the shortest and most reliable path to
8133
05:54:44,940 --> 05:54:45,940
our destination
8134
05:54:46,200 --> 05:54:47,200
here on the fourth layer also called the
8135
05:54:49,020 --> 05:54:50,020
transport layer some crucial functions
8136
05:54:51,480 --> 05:54:52,480
are taking place now one of these
8137
05:54:53,520 --> 05:54:54,520
functions is reliability it can be said
8138
05:54:56,760 --> 05:54:57,760
that the TCP protocol what you might
8139
05:55:00,360 --> 05:55:01,360
have heard in TCP IP if IP was on the
8140
05:55:05,218 --> 05:55:06,218
layer 3 perhaps then layer four is TCP
8141
05:55:09,360 --> 05:55:10,360
the TCP portion operates on this layer
8142
05:55:12,718 --> 05:55:13,718
or at least close enough to the
8143
05:55:14,340 --> 05:55:15,340
transport layer to be considered a layer
8144
05:55:16,320 --> 05:55:17,320
4 Protocol
8145
05:55:17,900 --> 05:55:18,900
just to sort of secondary side note and
8146
05:55:21,180 --> 05:55:22,180
we'll talk about TCP and IP a little bit
8147
05:55:23,700 --> 05:55:24,700
more in depth in the next module they
8148
05:55:25,558 --> 05:55:26,558
have their own model the OSI model is
8149
05:55:28,378 --> 05:55:29,378
sort of a theoretical model it was never
8150
05:55:30,058 --> 05:55:31,058
actually implemented as it was created
8151
05:55:32,700 --> 05:55:33,700
that being said we still use it in
8152
05:55:34,980 --> 05:55:35,980
discussing a lot of stuff which is why
8153
05:55:36,540 --> 05:55:37,540
we need to talk about so the reliability
8154
05:55:39,058 --> 05:55:40,058
is guaranteed by in here the connection
8155
05:55:43,080 --> 05:55:44,080
oriented
8156
05:55:50,660 --> 05:55:51,660
protocols that are on layer four
8157
05:55:53,400 --> 05:55:54,400
so the transport layer has mechanisms
8158
05:55:55,620 --> 05:55:56,620
that keep track of uh these segments and
8159
05:56:00,420 --> 05:56:01,420
when segments fail the transport layer
8160
05:56:02,878 --> 05:56:03,878
resends them there's also this
8161
05:56:04,920 --> 05:56:05,920
acknowledgment feature such as a like a
8162
05:56:08,218 --> 05:56:09,218
certified letter would have that ensures
8163
05:56:10,440 --> 05:56:11,440
that when a message is received by the
8164
05:56:12,780 --> 05:56:13,780
destination the transport layer is
8165
05:56:15,180 --> 05:56:16,180
notified for instance by a message
8166
05:56:17,580 --> 05:56:18,580
received successfully what we call a ack
8167
05:56:21,240 --> 05:56:22,240
packet or acknowledgment packet
8168
05:56:25,160 --> 05:56:26,160
besides these guaranteed delivery
8169
05:56:28,138 --> 05:56:29,138
features we also have what's called data
8170
05:56:30,780 --> 05:56:31,780
flow control this function ensures that
8171
05:56:33,780 --> 05:56:34,780
during the data transfer the receiving
8172
05:56:36,180 --> 05:56:37,180
end doesn't get flooded with too much
8173
05:56:38,040 --> 05:56:39,040
data at any one time later in the lesson
8174
05:56:40,920 --> 05:56:41,920
we're going to talk about different data
8175
05:56:42,900 --> 05:56:43,900
flow
8176
05:56:43,878 --> 05:56:44,878
techniques and flow control techniques
8177
05:56:46,260 --> 05:56:47,260
that are used the transport layer is
8178
05:56:48,540 --> 05:56:49,540
where something else called sequencing
8179
05:56:50,520 --> 05:56:51,520
of data occurs basically when data is
8180
05:56:53,340 --> 05:56:54,340
transmitted it's either broken apart or
8181
05:56:56,218 --> 05:56:57,218
fragmented to be able to send it across
8182
05:56:58,320 --> 05:56:59,320
the medium and when it's fragmented each
8183
05:57:00,718 --> 05:57:01,718
fragment or piece is labeled with a
8184
05:57:03,360 --> 05:57:04,360
specific number so that when the
8185
05:57:05,218 --> 05:57:06,218
receiving end receives uh when the
8186
05:57:08,040 --> 05:57:09,040
receiving end of the transport layer
8187
05:57:09,600 --> 05:57:10,600
receives this data it can be reassembled
8188
05:57:12,600 --> 05:57:13,600
and put back together in the proper
8189
05:57:14,400 --> 05:57:15,400
order this is really important
8190
05:57:15,958 --> 05:57:16,958
especially when data is received out of
8191
05:57:18,180 --> 05:57:19,180
order as I just demonstrated now in
8192
05:57:21,000 --> 05:57:22,000
essence this layer is much like the
8193
05:57:23,878 --> 05:57:24,878
standards and the laws that we have in
8194
05:57:26,040 --> 05:57:27,040
place on our highways they ensure that
8195
05:57:27,900 --> 05:57:28,900
Vehicles get us to where we need to be
8196
05:57:30,240 --> 05:57:31,240
safely and on time now some of the other
8197
05:57:32,940 --> 05:57:33,940
protocols you may have heard of that
8198
05:57:34,620 --> 05:57:35,620
operate on this layer are sctp uh some
8199
05:57:39,120 --> 05:57:40,120
tunneling protocols and uh more
8200
05:57:42,600 --> 05:57:43,600
importantly here when data is sort of
8201
05:57:45,058 --> 05:57:46,058
partitioned out it's called a segment as
8202
05:57:48,058 --> 05:57:49,058
opposed to a datagram or a frame now the
8203
05:57:52,620 --> 05:57:53,620
next layer is uh I think it's one of the
8204
05:57:55,860 --> 05:57:56,860
easier ones to memorize it's called the
8205
05:57:58,080 --> 05:57:59,080
session layer and layer five and it's
8206
05:58:00,718 --> 05:58:01,718
pretty simple because the sole purpose
8207
05:58:03,120 --> 05:58:04,120
of this layer is to establish maintain
8208
05:58:05,580 --> 05:58:06,580
when it comes time to shut down or
8209
05:58:08,520 --> 05:58:09,520
conclude the communication session now
8210
05:58:11,700 --> 05:58:12,700
while the OSI model assigns the
8211
05:58:13,740 --> 05:58:14,740
responsibility of this termination of
8212
05:58:16,558 --> 05:58:17,558
sessions to the session layer some other
8213
05:58:19,860 --> 05:58:20,860
models have performed this on a
8214
05:58:21,480 --> 05:58:22,480
different layer and we'll talk about
8215
05:58:22,680 --> 05:58:23,680
that a little bit more some of the
8216
05:58:24,780 --> 05:58:25,780
protocols you might see on here are for
8217
05:58:27,718 --> 05:58:28,718
instance RPC which stands for remote
8218
05:58:30,480 --> 05:58:31,480
procedure call and
8219
05:58:33,860 --> 05:58:34,860
TLS and SSL as well so this layer
8220
05:58:38,700 --> 05:58:39,700
manages how and for how long and what
8221
05:58:42,000 --> 05:58:43,000
way a device is going to establish a
8222
05:58:46,080 --> 05:58:47,080
connection during the communications
8223
05:58:47,638 --> 05:58:48,638
process that the layer is not yet
8224
05:58:49,680 --> 05:58:50,680
completed with its functions the rest of
8225
05:58:51,718 --> 05:58:52,718
the network just has to wait
8226
05:58:54,058 --> 05:58:55,058
so in keeping with the analogy of the
8227
05:58:56,458 --> 05:58:57,458
boss in order to understand how the
8228
05:58:58,138 --> 05:58:59,138
session layer fits in let's take a look
8229
05:59:00,000 --> 05:59:01,000
at exactly why we're using our buses is
8230
05:59:03,600 --> 05:59:04,600
it for transporting people or is it for
8231
05:59:06,000 --> 05:59:07,000
transporting top secret documents from
8232
05:59:09,000 --> 05:59:10,000
the main office building to the remote
8233
05:59:10,260 --> 05:59:11,260
office this Y is going to determine
8234
05:59:13,138 --> 05:59:14,138
several things for this layer right if
8235
05:59:15,360 --> 05:59:16,360
it's determined that we need
8236
05:59:17,760 --> 05:59:18,760
um
8237
05:59:18,600 --> 05:59:19,600
several connections to take a private
8238
05:59:22,260 --> 05:59:23,260
Highway for instance it might be
8239
05:59:24,058 --> 05:59:25,058
determined that we need a private bus to
8240
05:59:27,000 --> 05:59:28,000
take
8241
05:59:27,780 --> 05:59:28,780
um
8242
05:59:28,558 --> 05:59:29,558
special documents
8243
05:59:30,680 --> 05:59:31,680
to maintain security or take a special
8244
05:59:33,420 --> 05:59:34,420
Highway for instance so the session
8245
05:59:35,458 --> 05:59:36,458
layer is what's responsible for
8246
05:59:37,700 --> 05:59:38,700
determining what type of data and how we
8247
05:59:40,500 --> 05:59:41,500
need to connect this session continuing
8248
05:59:42,480 --> 05:59:43,480
on to the next layer is the presentation
8249
05:59:44,400 --> 05:59:45,400
layer or layer six this layer is
8250
05:59:46,740 --> 05:59:47,740
responsible for taking the data from the
8251
05:59:48,780 --> 05:59:49,780
application layer which is the next
8252
05:59:50,340 --> 05:59:51,340
layer we'll talk about and translating
8253
05:59:52,320 --> 05:59:53,320
it into an intermediary language that
8254
05:59:55,320 --> 05:59:56,320
the rest of the network can understand
8255
05:59:56,660 --> 05:59:57,660
and it's also going to perform it in
8256
05:59:59,040 --> 06:00:00,040
reverse on the receiving end also in
8257
06:00:01,378 --> 06:00:02,378
this layer data encryption and
8258
06:00:03,180 --> 06:00:04,180
compression takes place sometimes called
8259
06:00:06,298 --> 06:00:07,298
the syntax layer because of its data
8260
06:00:09,718 --> 06:00:10,718
encryption abilities as well as its
8261
06:00:12,660 --> 06:00:13,660
conversion to a network relatable format
8262
06:00:15,540 --> 06:00:16,540
or a format that applications can
8263
06:00:18,180 --> 06:00:19,180
understand now what this really means is
8264
06:00:21,660 --> 06:00:22,660
because the applications is going to
8265
06:00:23,340 --> 06:00:24,340
have its own syntax or its own language
8266
06:00:26,458 --> 06:00:27,458
the presentation layer is going to try
8267
06:00:28,378 --> 06:00:29,378
to a map between those languages now if
8268
06:00:31,138 --> 06:00:32,138
the mapping is available
8269
06:00:33,058 --> 06:00:34,058
then the presentation layer is going to
8270
06:00:34,798 --> 06:00:35,798
convert the data into Data units for the
8271
06:00:37,500 --> 06:00:38,500
session protocol and after that it's
8272
06:00:39,058 --> 06:00:40,058
send down the stack down the rest of the
8273
06:00:41,340 --> 06:00:42,340
layers to do everything else it needs to
8274
06:00:43,378 --> 06:00:44,378
do some of the protocols that operate
8275
06:00:45,540 --> 06:00:46,540
this layer are
8276
06:00:47,360 --> 06:00:48,360
anything that's dealing with compression
8277
06:00:49,860 --> 06:00:50,860
for instance PNG jpegs
8278
06:00:56,040 --> 06:00:57,040
Tiff a lot of these sort of picture
8279
06:01:01,378 --> 06:01:02,378
file extension that you've seen this
8280
06:01:04,200 --> 06:01:05,200
layer also performs code conversions
8281
06:01:06,058 --> 06:01:07,058
they're going to take raw application
8282
06:01:07,440 --> 06:01:08,440
data and compress them into more
8283
06:01:09,240 --> 06:01:10,240
manageable forms for transmitting now
8284
06:01:12,120 --> 06:01:13,120
regarding the translation capabilities
8285
06:01:14,100 --> 06:01:15,100
of this layer think of like two
8286
06:01:16,200 --> 06:01:17,200
different systems that are very
8287
06:01:18,480 --> 06:01:19,480
different from each other one perhaps
8288
06:01:20,400 --> 06:01:21,400
using TCP which we know another using
8289
06:01:22,920 --> 06:01:23,920
ipx SPX which you don't worry about but
8290
06:01:26,160 --> 06:01:27,160
it's another sort of protocol Suite this
8291
06:01:28,440 --> 06:01:29,440
layer is what makes Communications
8292
06:01:30,058 --> 06:01:31,058
available because of this we also know
8293
06:01:33,058 --> 06:01:34,058
that a Gateway device if you recall from
8294
06:01:36,240 --> 06:01:37,240
the devices we've talked about
8295
06:01:38,340 --> 06:01:39,340
is a device that's going to operate on
8296
06:01:40,860 --> 06:01:41,860
this layer
8297
06:01:42,120 --> 06:01:43,120
because it's converting between two
8298
06:01:43,980 --> 06:01:44,980
different types of Networks
8299
06:01:46,320 --> 06:01:47,320
this is the biggest difference between a
8300
06:01:48,900 --> 06:01:49,900
gateway
8301
06:01:50,638 --> 06:01:51,638
and a router which as you recall
8302
06:01:53,180 --> 06:01:54,180
operates on layer 3.
8303
06:01:57,780 --> 06:01:58,780
a transceiver by the way and you
8304
06:02:00,180 --> 06:02:01,180
remember a transceiver is that device
8305
06:02:02,878 --> 06:02:03,878
that is on a
8306
06:02:04,980 --> 06:02:05,980
Nick it's going to allow you to talk for
8307
06:02:07,320 --> 06:02:08,320
instance between a copper and fiber
8308
06:02:09,240 --> 06:02:10,240
Network also might work on this
8309
06:02:12,360 --> 06:02:13,360
presentation layer depending on how we
8310
06:02:14,638 --> 06:02:15,638
Define it other people might actually
8311
06:02:16,260 --> 06:02:17,260
say it works on a physical layer now to
8312
06:02:18,958 --> 06:02:19,958
put this layer in perspective the
8313
06:02:20,940 --> 06:02:21,940
presentation layer is like having a
8314
06:02:22,558 --> 06:02:23,558
double decker bus with a tour guide on a
8315
06:02:25,138 --> 06:02:26,138
microphone who's translating everything
8316
06:02:26,700 --> 06:02:27,700
that can be seen and heard to the
8317
06:02:29,340 --> 06:02:30,340
passengers the tour guide is also going
8318
06:02:31,440 --> 06:02:32,440
to help repack the tourists luggage for
8319
06:02:33,718 --> 06:02:34,718
them which is like a compression
8320
06:02:37,200 --> 06:02:38,200
and it's also going to add another level
8321
06:02:39,120 --> 06:02:40,120
of security for VIP passengers
8322
06:02:44,040 --> 06:02:45,040
who might come on board this is just
8323
06:02:46,680 --> 06:02:47,680
like
8324
06:02:48,180 --> 06:02:49,180
encryption
8325
06:02:50,760 --> 06:02:51,760
here the formatting is simply making
8326
06:02:53,458 --> 06:02:54,458
sure that the passengers are briefed and
8327
06:02:56,040 --> 06:02:57,040
ready for their tour and making sure
8328
06:02:58,080 --> 06:02:59,080
that they or the data is ready for the
8329
06:03:00,958 --> 06:03:01,958
application so again we're really
8330
06:03:02,820 --> 06:03:03,820
packaging this up for presentation to
8331
06:03:06,000 --> 06:03:07,000
the application layer and the
8332
06:03:08,040 --> 06:03:09,040
terminology for data at this point is
8333
06:03:10,740 --> 06:03:11,740
going to be actually called Data so this
8334
06:03:12,780 --> 06:03:13,780
is where we're moving up in the world
8335
06:03:14,458 --> 06:03:15,458
we're no longer talking about segments
8336
06:03:17,218 --> 06:03:18,218
or datagrams or frames we're here now
8337
06:03:19,620 --> 06:03:20,620
talking about data it's packaged in a
8338
06:03:21,780 --> 06:03:22,780
way that an application can read it
8339
06:03:23,820 --> 06:03:24,820
finally at the topmost layer we have the
8340
06:03:26,520 --> 06:03:27,520
application layer this is the layer
8341
06:03:28,378 --> 06:03:29,378
that's closest to
8342
06:03:31,798 --> 06:03:32,798
the user and it's the only one that the
8343
06:03:34,378 --> 06:03:35,378
typical end user is going to be
8344
06:03:35,820 --> 06:03:36,820
interacting with now even though it's
8345
06:03:37,620 --> 06:03:38,620
called the application layer this
8346
06:03:40,138 --> 06:03:41,138
doesn't mean that the application itself
8347
06:03:42,480 --> 06:03:43,480
is on this layer but that the
8348
06:03:45,120 --> 06:03:46,120
application layer provides utilities and
8349
06:03:48,660 --> 06:03:49,660
services that an application could use
8350
06:03:51,180 --> 06:03:52,180
for accessing network resources like
8351
06:03:53,520 --> 06:03:54,520
some of these that we've talked about
8352
06:03:55,040 --> 06:03:56,040
SMTP which allows you to get email DNS
8353
06:03:58,200 --> 06:03:59,200
which is going to translate between an
8354
06:03:59,820 --> 06:04:00,820
IP address and a fully qualified domain
8355
06:04:03,600 --> 06:04:04,600
name FTP which is going to allow for
8356
06:04:06,000 --> 06:04:07,000
file transferring ntp Network time
8357
06:04:08,580 --> 06:04:09,580
protocol which is going to keep time up
8358
06:04:09,958 --> 06:04:10,958
to date and HTTP which allows us to
8359
06:04:11,820 --> 06:04:12,820
browse so for example let's say you have
8360
06:04:13,920 --> 06:04:14,920
a file that you'd like to transfer to a
8361
06:04:16,138 --> 06:04:17,138
remote computer right what method you're
8362
06:04:18,240 --> 06:04:19,240
going to use FTP now the application
8363
06:04:21,180 --> 06:04:22,180
layer provides the FTP services to the
8364
06:04:24,540 --> 06:04:25,540
application you use which is some sort
8365
06:04:26,878 --> 06:04:27,878
of FTP client the FTP client itself does
8366
06:04:30,900 --> 06:04:31,900
not exist on the app application layer
8367
06:04:32,940 --> 06:04:33,940
simply the protocol does this layer is
8368
06:04:36,660 --> 06:04:37,660
the one you've probably dealt with the
8369
06:04:38,458 --> 06:04:39,458
most and you're probably likely already
8370
06:04:40,558 --> 06:04:41,558
familiar with without even realizing it
8371
06:04:42,360 --> 06:04:43,360
for example you utilize this layer every
8372
06:04:44,520 --> 06:04:45,520
time you check your email browse Etc and
8373
06:04:47,280 --> 06:04:48,280
so on now some of these might not fit
8374
06:04:50,340 --> 06:04:51,340
perfectly into the application layer and
8375
06:04:52,260 --> 06:04:53,260
that's because again this is a
8376
06:04:53,760 --> 06:04:54,760
theoretical model when we talk about the
8377
06:04:55,620 --> 06:04:56,620
TCP model next it will see this working
8378
06:04:59,218 --> 06:05:00,218
in a lot more of a practical way now
8379
06:05:01,320 --> 06:05:02,320
because we all know we have many
8380
06:05:02,878 --> 06:05:03,878
different applications on every one of
8381
06:05:04,440 --> 06:05:05,440
our computers one of the purpose of the
8382
06:05:06,540 --> 06:05:07,540
application layer is to regulate the
8383
06:05:08,458 --> 06:05:09,458
communications between these
8384
06:05:10,080 --> 06:05:11,080
applications and manage when they
8385
06:05:12,540 --> 06:05:13,540
request services and resources so while
8386
06:05:15,000 --> 06:05:16,000
it might seem easy to lump all
8387
06:05:17,100 --> 06:05:18,100
applications together when talking about
8388
06:05:19,020 --> 06:05:20,020
this layer the only applications that
8389
06:05:21,298 --> 06:05:22,298
this layer is actually going to manage
8390
06:05:22,740 --> 06:05:23,740
are those that have a Communications
8391
06:05:25,740 --> 06:05:26,740
component
8392
06:05:27,860 --> 06:05:28,860
so Solitaire would not qualify for this
8393
06:05:31,980 --> 06:05:32,980
right but Internet Explorer which has
8394
06:05:34,620 --> 06:05:35,620
all those browsing and protocols FTP DNS
8395
06:05:38,700 --> 06:05:39,700
Etc is going to uh deal with this so
8396
06:05:41,878 --> 06:05:42,878
this layer is also responsible for
8397
06:05:43,860 --> 06:05:44,860
network access a certain level of error
8398
06:05:46,920 --> 06:05:47,920
recovery and it's also capable of some
8399
06:05:49,320 --> 06:05:50,320
data flow measures there's a lot of
8400
06:05:50,940 --> 06:05:51,940
redundancy here as this is the seventh
8401
06:05:53,580 --> 06:05:54,580
and the final layer this is where the
8402
06:05:55,320 --> 06:05:56,320
information or process either starts
8403
06:06:00,860 --> 06:06:01,860
or finishes
8404
06:06:05,940 --> 06:06:06,940
so an application is going to create
8405
06:06:07,798 --> 06:06:08,798
what it needs to be sent here and then
8406
06:06:09,540 --> 06:06:10,540
unwrap the data once it's sent uh from
8407
06:06:12,540 --> 06:06:13,540
one computer the next so to finish off
8408
06:06:14,760 --> 06:06:15,760
our analogy of the bus
8409
06:06:17,218 --> 06:06:18,218
um this is sort of like the bus station
8410
06:06:19,080 --> 06:06:20,080
here's where all the people wait in line
8411
06:06:20,940 --> 06:06:21,940
to get tickets to use the bus they're
8412
06:06:22,980 --> 06:06:23,980
going to dictate the bus station is
8413
06:06:24,660 --> 06:06:25,660
going to dictate who has access to the
8414
06:06:26,580 --> 06:06:27,580
resources the resources being these
8415
06:06:28,320 --> 06:06:29,320
buses and it's going to receive all the
8416
06:06:30,480 --> 06:06:31,480
incoming drop-offs and process them as
8417
06:06:33,000 --> 06:06:34,000
well as control the flow of people in
8418
06:06:34,920 --> 06:06:35,920
and out of the station and it's going to
8419
06:06:36,600 --> 06:06:37,600
notify people if there are problems on
8420
06:06:38,218 --> 06:06:39,218
the highways and so on just as users are
8421
06:06:40,920 --> 06:06:41,920
typically mostly going to interact with
8422
06:06:43,020 --> 06:06:44,020
the application layer the bus riders are
8423
06:06:45,240 --> 06:06:46,240
really only going to interact at the bus
8424
06:06:47,218 --> 06:06:48,218
station layer right they're not going to
8425
06:06:48,958 --> 06:06:49,958
be interacting with mechanics and
8426
06:06:50,280 --> 06:06:51,280
building the bus or maintaining the bus
8427
06:06:51,900 --> 06:06:52,900
or dispatching individuals or any of
8428
06:06:54,718 --> 06:06:55,718
that stuff in most cases they're not
8429
06:06:56,280 --> 06:06:57,280
even going to be interacting with the
8430
06:06:58,080 --> 06:06:59,080
individual driving the bus so this is
8431
06:07:00,180 --> 06:07:01,180
really where users are going to be doing
8432
06:07:03,000 --> 06:07:04,000
most of their interacting now after
8433
06:07:05,040 --> 06:07:06,040
going through each of of these layers we
8434
06:07:07,378 --> 06:07:08,378
can now begin to have an understanding
8435
06:07:09,058 --> 06:07:10,058
on how they're grouped together
8436
06:07:10,980 --> 06:07:11,980
for instance layers 5 6 and 7 are what
8437
06:07:15,120 --> 06:07:16,120
we call application support block when
8438
06:07:18,120 --> 06:07:19,120
we look at each of these layers
8439
06:07:19,260 --> 06:07:20,260
individually we can very easily see that
8440
06:07:21,840 --> 06:07:22,840
the functions of each play a very
8441
06:07:24,298 --> 06:07:25,298
specific role in the application
8442
06:07:26,638 --> 06:07:27,638
management support and keeping them
8443
06:07:29,520 --> 06:07:30,520
consistent the remaining four layers
8444
06:07:32,040 --> 06:07:33,040
from the transport layer down to the
8445
06:07:34,378 --> 06:07:35,378
physical layer are what we call the
8446
06:07:36,298 --> 06:07:37,298
network support block these layers and
8447
06:07:39,360 --> 06:07:40,360
the protocols and devices that operate
8448
06:07:41,340 --> 06:07:42,340
on them are all Network related whether
8449
06:07:44,760 --> 06:07:45,760
it's for routing or switching on the
8450
06:07:46,620 --> 06:07:47,620
network or ensuring data delivery on the
8451
06:07:48,780 --> 06:07:49,780
network and so on perhaps even making
8452
06:07:51,298 --> 06:07:52,298
sure that the actual bits all the way
8453
06:07:53,400 --> 06:07:54,400
down to those bits of data being
8454
06:07:55,200 --> 06:07:56,200
communicated now as technicians and
8455
06:07:57,298 --> 06:07:58,298
specifically for the exam you really
8456
06:07:59,458 --> 06:08:00,458
want to know which layer relates to
8457
06:08:02,040 --> 06:08:03,040
which support blocks and also this is
8458
06:08:04,320 --> 06:08:05,320
going to help a great deal when we
8459
06:08:05,400 --> 06:08:06,400
discuss the next networking model which
8460
06:08:07,260 --> 06:08:08,260
is the tcpip layer model so uh just to
8461
06:08:12,420 --> 06:08:13,420
sort of go through this again
8462
06:08:15,000 --> 06:08:16,000
we start here at the application layer
8463
06:08:18,600 --> 06:08:19,600
and we work our way down until we get
8464
06:08:21,780 --> 06:08:22,780
down to the physical layer which is
8465
06:08:23,878 --> 06:08:24,878
where the data can actually be
8466
06:08:25,500 --> 06:08:26,500
transmitted
8467
06:08:27,900 --> 06:08:28,900
over the network and then it builds its
8468
06:08:30,660 --> 06:08:31,660
way back up until we get to the last
8469
06:08:32,940 --> 06:08:33,940
application so if I'm browsing uh let's
8470
06:08:36,120 --> 06:08:37,120
say this is me
8471
06:08:38,700 --> 06:08:39,700
right and this is a web
8472
06:08:41,820 --> 06:08:42,820
sort of server
8473
06:08:44,760 --> 06:08:45,760
I send a request the request goes down
8474
06:08:49,320 --> 06:08:50,320
all the way goes over the network it
8475
06:08:52,798 --> 06:08:53,798
might even hit a couple routers along
8476
06:08:54,480 --> 06:08:55,480
the way
8477
06:08:56,400 --> 06:08:57,400
or switches rather
8478
06:09:00,480 --> 06:09:01,480
so we're hitting some switches and then
8479
06:09:01,860 --> 06:09:02,860
we hit some routers then we had some
8480
06:09:03,420 --> 06:09:04,420
switches and then it's going to go all
8481
06:09:06,058 --> 06:09:07,058
the way up again to the web server and
8482
06:09:08,400 --> 06:09:09,400
then the web server is going to send
8483
06:09:09,660 --> 06:09:10,660
that data back Etc and so we go this
8484
06:09:13,020 --> 06:09:14,020
really follows on each end how data is
8485
06:09:16,138 --> 06:09:17,138
being sent and received so before we
8486
06:09:19,320 --> 06:09:20,320
wrap this up there's a couple ways to
8487
06:09:21,540 --> 06:09:22,540
remember these and I'd really highly
8488
06:09:23,340 --> 06:09:24,340
recommend committing this OSI model to
8489
06:09:25,558 --> 06:09:26,558
memory there's two ways we do this one
8490
06:09:27,540 --> 06:09:28,540
is called the top
8491
06:09:31,218 --> 06:09:32,218
down approach this starts with layer
8492
06:09:35,218 --> 06:09:36,218
seven
8493
06:09:36,240 --> 06:09:37,240
and ends with layer one now the reason
8494
06:09:38,580 --> 06:09:39,580
you want to just remember whichever
8495
06:09:40,260 --> 06:09:41,260
mnemonic device I'm about to tell you
8496
06:09:41,580 --> 06:09:42,580
just remember which one you're
8497
06:09:42,540 --> 06:09:43,540
remembering so that way you know how to
8498
06:09:43,860 --> 06:09:44,860
write it
8499
06:09:45,000 --> 06:09:46,000
a great way to remember this one is all
8500
06:09:47,340 --> 06:09:48,340
people seem to need delicious pizza
8501
06:09:50,040 --> 06:09:51,040
uh now again all his application starts
8502
06:09:53,340 --> 06:09:54,340
at seven so we're starting with the user
8503
06:09:56,280 --> 06:09:57,280
and we're going down to physical to the
8504
06:09:59,458 --> 06:10:00,458
hardware
8505
06:10:02,218 --> 06:10:03,218
now the other way I like to remember
8506
06:10:03,840 --> 06:10:04,840
this is uh please do not throw sausage
8507
06:10:09,240 --> 06:10:10,240
pizza away that's my particular favorite
8508
06:10:11,520 --> 06:10:12,520
now here we're taking a bottom
8509
06:10:16,920 --> 06:10:17,920
up approach because we're going from the
8510
06:10:18,840 --> 06:10:19,840
bottom up so realize that this you're
8511
06:10:20,940 --> 06:10:21,940
starting with the physical layer
8512
06:10:23,520 --> 06:10:24,520
and going up to the application layer so
8513
06:10:26,340 --> 06:10:27,340
however which one of one of these you
8514
06:10:28,138 --> 06:10:29,138
memorize you use to memorize this uh
8515
06:10:30,900 --> 06:10:31,900
just remember to commit it to memory and
8516
06:10:32,820 --> 06:10:33,820
when you get to your exam write it down
8517
06:10:34,740 --> 06:10:35,740
immediately so you can just look at it
8518
06:10:36,600 --> 06:10:37,600
and remember this is seven six five four
8519
06:10:41,958 --> 06:10:42,958
three two one this is where hubs would
8520
06:10:46,980 --> 06:10:47,980
function again uh they're just
8521
06:10:49,138 --> 06:10:50,138
forwarding the same information just
8522
06:10:50,820 --> 06:10:51,820
like this is where a cable would
8523
06:10:52,558 --> 06:10:53,558
function data link is where most
8524
06:10:55,080 --> 06:10:56,080
switches are going to function and on
8525
06:10:58,200 --> 06:10:59,200
the network layer that's where we're
8526
06:10:59,458 --> 06:11:00,458
going to see routers function this is
8527
06:11:01,920 --> 06:11:02,920
the most information that I see on the
8528
06:11:04,020 --> 06:11:05,020
exam and so if you Commit This to Memory
8529
06:11:05,638 --> 06:11:06,638
I think you'll be set
8530
06:11:07,798 --> 06:11:08,798
okay so just to recap one last time and
8531
06:11:10,740 --> 06:11:11,740
review everything we've discussed first
8532
06:11:12,780 --> 06:11:13,780
we explained the history and the purpose
8533
06:11:15,298 --> 06:11:16,298
of the OSI model remember the important
8534
06:11:17,638 --> 06:11:18,638
thing to realize here is that it's a
8535
06:11:20,040 --> 06:11:21,040
layered model and the reason it's
8536
06:11:21,660 --> 06:11:22,660
layered is to make it easier not only to
8537
06:11:25,040 --> 06:11:26,040
develop things for each layer instead of
8538
06:11:27,958 --> 06:11:28,958
having to develop something for the
8539
06:11:29,400 --> 06:11:30,400
entire system I can just develop one
8540
06:11:31,620 --> 06:11:32,620
little device such as a router or a
8541
06:11:34,860 --> 06:11:35,860
switch and also it's going to be easier
8542
06:11:37,138 --> 06:11:38,138
to troubleshoot and fix anything that
8543
06:11:40,378 --> 06:11:41,378
goes wrong
8544
06:11:41,458 --> 06:11:42,458
we then talked about layer one the
8545
06:11:43,980 --> 06:11:44,980
physical layer right and this is uh
8546
06:11:46,798 --> 06:11:47,798
where chords
8547
06:11:48,900 --> 06:11:49,900
for instance the media exists
8548
06:11:53,160 --> 06:11:54,160
and where all the bits are going to go
8549
06:11:55,320 --> 06:11:56,320
from one place to the other we're really
8550
06:11:57,360 --> 06:11:58,360
here dealing with the ones and zeros the
8551
06:11:59,638 --> 06:12:00,638
electrical bits also remember hubs exist
8552
06:12:02,760 --> 06:12:03,760
here as well
8553
06:12:03,958 --> 06:12:04,958
we then talked about the data link layer
8554
06:12:06,958 --> 06:12:07,958
this also had two sub-layers Mac
8555
06:12:10,980 --> 06:12:11,980
and LLC
8556
06:12:13,620 --> 06:12:14,620
and this is where we see Mac addressing
8557
06:12:17,040 --> 06:12:18,040
or physical addresses start to occur and
8558
06:12:21,180 --> 06:12:22,180
that means that here is where we're
8559
06:12:22,740 --> 06:12:23,740
really going to deal
8560
06:12:24,058 --> 06:12:25,058
with switches
8561
06:12:28,200 --> 06:12:29,200
the data here by the way is called is
8562
06:12:30,900 --> 06:12:31,900
put into what we call frames instead of
8563
06:12:33,240 --> 06:12:34,240
just dealing with bits
8564
06:12:36,180 --> 06:12:37,180
now the next layer is the network layer
8565
06:12:38,878 --> 06:12:39,878
and this is where we start to see
8566
06:12:42,000 --> 06:12:43,000
routing and this is thanks to a new
8567
06:12:44,878 --> 06:12:45,878
addressing system specifically the one
8568
06:12:47,458 --> 06:12:48,458
we're going to see the most is IP
8569
06:12:49,138 --> 06:12:50,138
addressing this means here is where
8570
06:12:51,298 --> 06:12:52,298
we're going to start seeing routers and
8571
06:12:53,878 --> 06:12:54,878
don't forget here we see start seeing uh
8572
06:12:57,298 --> 06:12:58,298
terminology for packets
8573
06:13:01,080 --> 06:13:02,080
and the one we mentioned too was
8574
06:13:05,180 --> 06:13:06,180
datagrams we also mentioned that this is
8575
06:13:08,280 --> 06:13:09,280
where we see connection loss
8576
06:13:14,280 --> 06:13:15,280
or connections that don't sort of have a
8577
06:13:16,980 --> 06:13:17,980
definite got sent or delivery receipt we
8578
06:13:21,058 --> 06:13:22,058
then looked at layer four which is where
8579
06:13:23,760 --> 06:13:24,760
we see TCP from the IP Suite right and
8580
06:13:27,958 --> 06:13:28,958
this is the one that's going to start
8581
06:13:29,160 --> 06:13:30,160
looking at guaranteeing our delivery
8582
06:13:37,320 --> 06:13:38,320
layer 4 is also where we ensure
8583
06:13:39,600 --> 06:13:40,600
reliability
8584
06:13:42,660 --> 06:13:43,660
and flow control
8585
06:13:47,820 --> 06:13:48,820
here information
8586
06:13:50,458 --> 06:13:51,458
is called segments when we get to layer
8587
06:13:52,980 --> 06:13:53,980
5 or the session layer we see that we're
8588
06:13:55,260 --> 06:13:56,260
really establishing and maintaining a
8589
06:13:57,600 --> 06:13:58,600
session
8590
06:14:03,120 --> 06:14:04,120
this is where we're going to start and
8591
06:14:04,980 --> 06:14:05,980
gracefully end our Communications such
8592
06:14:07,980 --> 06:14:08,980
as SSL Communications when we get to
8593
06:14:11,100 --> 06:14:12,100
layer 6 this is where encryption
8594
06:14:16,200 --> 06:14:17,200
and compression occur
8595
06:14:22,740 --> 06:14:23,740
this is also where we start seeing the
8596
06:14:24,600 --> 06:14:25,600
term
8597
06:14:25,440 --> 06:14:26,440
data
8598
06:14:27,360 --> 06:14:28,360
finally we talked about the application
8599
06:14:30,058 --> 06:14:31,058
layer
8600
06:14:32,040 --> 06:14:33,040
or layer seven this is the layer that's
8601
06:14:34,620 --> 06:14:35,620
closest to the user
8602
06:14:38,100 --> 06:14:39,100
and this is where you're really going to
8603
06:14:39,600 --> 06:14:40,600
see the interaction this is where we saw
8604
06:14:41,700 --> 06:14:42,700
a lot of the stuff such as SMTP
8605
06:14:46,200 --> 06:14:47,200
FTP
8606
06:14:49,280 --> 06:14:50,280
HTTP and so on
8607
06:14:51,540 --> 06:14:52,540
this really governs everything so if we
8608
06:14:53,940 --> 06:14:54,940
go back through this with our metaphor
8609
06:14:55,320 --> 06:14:56,320
remember the physical layer are the
8610
06:14:57,240 --> 06:14:58,240
highways
8611
06:15:00,298 --> 06:15:01,298
the date of the link layer or how we're
8612
06:15:02,040 --> 06:15:03,040
going to share the roads
8613
06:15:05,580 --> 06:15:06,580
remember we thought about a stop light
8614
06:15:09,120 --> 06:15:10,120
the network layer is where we start
8615
06:15:11,280 --> 06:15:12,280
determining the best route to get from
8616
06:15:13,620 --> 06:15:14,620
one place to the other
8617
06:15:15,900 --> 06:15:16,900
the transport layer tells us for
8618
06:15:17,940 --> 06:15:18,940
instance the rules of the road
8619
06:15:22,138 --> 06:15:23,138
the session layer is what type of
8620
06:15:24,840 --> 06:15:25,840
Highway we might need to take
8621
06:15:28,558 --> 06:15:29,558
for instance I might need to take a
8622
06:15:31,980 --> 06:15:32,980
um a special private Highway if I have
8623
06:15:34,798 --> 06:15:35,798
important documents the presentation
8624
06:15:37,260 --> 06:15:38,260
layer is like the bus driver
8625
06:15:40,798 --> 06:15:41,798
who is going to pack up our bags for us
8626
06:15:43,260 --> 06:15:44,260
and also communicate and make sure that
8627
06:15:44,820 --> 06:15:45,820
we know where we're going and the
8628
06:15:46,320 --> 06:15:47,320
application layer is going to be like
8629
06:15:49,860 --> 06:15:50,860
the bus stop
8630
06:15:54,058 --> 06:15:55,058
now the OSI model is in actuality pretty
8631
06:15:57,298 --> 06:15:58,298
obsolete but we need to understand the
8632
06:15:59,520 --> 06:16:00,520
theory behind it before we can get into
8633
06:16:01,138 --> 06:16:02,138
something that's a little more
8634
06:16:03,000 --> 06:16:04,000
um uh necessary for instance the tcpip
8635
06:16:06,360 --> 06:16:07,360
layer model
8636
06:16:11,400 --> 06:16:12,400
[Music]
8637
06:16:33,180 --> 06:16:34,180
Network infrastructure and Design
8638
06:16:35,400 --> 06:16:36,400
Network models the TCP model
8639
06:16:39,718 --> 06:16:40,718
whereas in the previous module we talked
8640
06:16:41,878 --> 06:16:42,878
about the OSI model A mostly theoretical
8641
06:16:44,638 --> 06:16:45,638
model that's in use in computer networks
8642
06:16:47,218 --> 06:16:48,218
in this module we're going to talk about
8643
06:16:49,020 --> 06:16:50,020
perhaps what is considered to be one of
8644
06:16:50,760 --> 06:16:51,760
the most common or at least the most
8645
06:16:53,100 --> 06:16:54,100
widely used model the TCP model now
8646
06:16:55,980 --> 06:16:56,980
while it's important that we memorize
8647
06:16:57,840 --> 06:16:58,840
and familiarize ourselves with the OSI
8648
06:16:59,458 --> 06:17:00,458
model it's also really important that we
8649
06:17:01,440 --> 06:17:02,440
understand this TCP model and the
8650
06:17:03,718 --> 06:17:04,718
differences between it and the OSI model
8651
06:17:07,200 --> 06:17:08,200
as technicians and administrators it's
8652
06:17:09,900 --> 06:17:10,900
really important that we're familiar
8653
06:17:11,700 --> 06:17:12,700
with each layer as well as how a data
8654
06:17:14,218 --> 06:17:15,218
transfers between all of these layers
8655
06:17:16,458 --> 06:17:17,458
and how all the protocols that are used
8656
06:17:19,080 --> 06:17:20,080
in TCP relate to one another and in the
8657
06:17:22,080 --> 06:17:23,080
layers
8658
06:17:23,160 --> 06:17:24,160
so
8659
06:17:24,298 --> 06:17:25,298
the objective of this module are first
8660
06:17:26,580 --> 06:17:27,580
to explain the purpose and depth of the
8661
06:17:28,500 --> 06:17:29,500
TCP model and to compare it in some ways
8662
06:17:31,920 --> 06:17:32,920
with the OSI model we're also going to
8663
06:17:34,200 --> 06:17:35,200
talk about what data encapsulation and
8664
06:17:36,780 --> 06:17:37,780
fragmentation are these are really key
8665
06:17:38,878 --> 06:17:39,878
to how large amounts of data are able to
8666
06:17:41,700 --> 06:17:42,700
be transmitted and transferred over the
8667
06:17:44,280 --> 06:17:45,280
Internet the largest Network in the
8668
06:17:46,620 --> 06:17:47,620
world
8669
06:17:47,340 --> 06:17:48,340
and then we're going to talk about the
8670
06:17:49,020 --> 06:17:50,020
four layers of the tcpip model beginning
8671
06:17:51,540 --> 06:17:52,540
with the fourth one and then the third
8672
06:17:53,458 --> 06:17:54,458
the second and the first
8673
06:17:56,100 --> 06:17:57,100
finally we're going to talk about
8674
06:17:57,840 --> 06:17:58,840
protocol binding and something called an
8675
06:18:00,718 --> 06:18:01,718
MTU black hole that doesn't really occur
8676
06:18:03,420 --> 06:18:04,420
much anymore but that Network plus wants
8677
06:18:05,340 --> 06:18:06,340
you to be familiar with
8678
06:18:06,900 --> 06:18:07,900
so as mentioned before the tcpap model
8679
06:18:09,660 --> 06:18:10,660
is perhaps the most widely known or used
8680
06:18:12,360 --> 06:18:13,360
networking model it's uh another
8681
06:18:14,878 --> 06:18:15,878
networking model that's most commonly
8682
06:18:17,160 --> 06:18:18,160
defined using abstract layers just like
8683
06:18:20,340 --> 06:18:21,340
we had with the OSI model and the entire
8684
06:18:22,620 --> 06:18:23,620
purpose of this model is to allow for
8685
06:18:24,440 --> 06:18:25,440
conceptualization of how a computer
8686
06:18:26,940 --> 06:18:27,940
network functions in maintaining
8687
06:18:29,400 --> 06:18:30,400
hardware and protocol interoperability
8688
06:18:32,878 --> 06:18:33,878
also it's commonly called the dod model
8689
06:18:38,160 --> 06:18:39,160
for the Department of Defense which
8690
06:18:40,740 --> 06:18:41,740
funded much of the research that went
8691
06:18:43,080 --> 06:18:44,080
into it uh TCP was permanently uh
8692
06:18:47,360 --> 06:18:48,360
activated in 1983 and it's been in use
8693
06:18:51,798 --> 06:18:52,798
just about ever since
8694
06:18:54,540 --> 06:18:55,540
that wasn't until 1985 this model was
8695
06:18:57,120 --> 06:18:58,120
actually commercially marketed but it is
8696
06:18:59,760 --> 06:19:00,760
now the preferred network standard for
8697
06:19:03,480 --> 06:19:04,480
protocols and so on
8698
06:19:05,280 --> 06:19:06,280
now this means that using these four
8699
06:19:08,760 --> 06:19:09,760
layers on this model the bottom being
8700
06:19:10,680 --> 06:19:11,680
the network interface layer the internet
8701
06:19:12,900 --> 06:19:13,900
layer the transport layer and then
8702
06:19:15,420 --> 06:19:16,420
finally the application layer and if you
8703
06:19:17,878 --> 06:19:18,878
know or remember the OSI model you'll
8704
06:19:19,798 --> 06:19:20,798
see that there is some resemblance uh
8705
06:19:22,020 --> 06:19:23,020
these understanding these this model and
8706
06:19:24,780 --> 06:19:25,780
understanding how data flows is actually
8707
06:19:26,940 --> 06:19:27,940
how the entire world is allowed to
8708
06:19:29,400 --> 06:19:30,400
communicate and connect to the network
8709
06:19:30,958 --> 06:19:31,958
so this is necessary for every computer
8710
06:19:34,138 --> 06:19:35,138
in the world that is currently using the
8711
06:19:36,660 --> 06:19:37,660
internet and for the most part that's on
8712
06:19:38,520 --> 06:19:39,520
any network we might find other smaller
8713
06:19:41,458 --> 06:19:42,458
lesser known protocols that do operate
8714
06:19:43,500 --> 06:19:44,500
outside of this but I think you would be
8715
06:19:45,958 --> 06:19:46,958
hard-pressed in today's day and age to
8716
06:19:47,940 --> 06:19:48,940
see that
8717
06:19:48,900 --> 06:19:49,900
so technicians and Engineers will
8718
06:19:51,780 --> 06:19:52,780
probably sit and talk about Technology's
8719
06:19:53,638 --> 06:19:54,638
implementation of these two models for
8720
06:19:55,558 --> 06:19:56,558
hours on end and the reason is because
8721
06:19:57,780 --> 06:19:58,780
there's quite a bit of history and
8722
06:19:59,040 --> 06:20:00,040
Brilliant thinking that went into the
8723
06:20:00,420 --> 06:20:01,420
creation of both of them the tcpap model
8724
06:20:03,420 --> 06:20:04,420
was in fact created before the OSI model
8725
06:20:06,058 --> 06:20:07,058
and it still makes it easier to
8726
06:20:08,160 --> 06:20:09,160
represent how communication and network
8727
06:20:09,900 --> 06:20:10,900
related Protocols are defined and relate
8728
06:20:12,480 --> 06:20:13,480
to one another however it's still more
8729
06:20:14,878 --> 06:20:15,878
common to hear technicians and
8730
06:20:16,138 --> 06:20:17,138
administrators use the OSI model when
8731
06:20:18,180 --> 06:20:19,180
they're troubleshooting or referencing
8732
06:20:19,740 --> 06:20:20,740
networking devices and there are many
8733
06:20:22,320 --> 06:20:23,320
similarities between the two models the
8734
06:20:25,320 --> 06:20:26,320
first similarity is the obvious use of
8735
06:20:27,120 --> 06:20:28,120
the layers to describe the functions of
8736
06:20:29,280 --> 06:20:30,280
these communication systems although in
8737
06:20:31,260 --> 06:20:32,260
tcpip we have four whereas in OSI as you
8738
06:20:34,500 --> 06:20:35,500
recall we have seven some of them even
8739
06:20:36,780 --> 06:20:37,780
have similar names as you can see uh
8740
06:20:40,920 --> 06:20:41,920
from application and transport and then
8741
06:20:43,680 --> 06:20:44,680
we see network or Internet and network
8742
06:20:46,080 --> 06:20:47,080
interface which is very much like
8743
06:20:47,700 --> 06:20:48,700
physical
8744
06:20:51,298 --> 06:20:52,298
in some ways some people consider the
8745
06:20:53,160 --> 06:20:54,160
TCP model to be a smaller version of The
8746
06:20:56,160 --> 06:20:57,160
OSI model however this leads to some
8747
06:20:58,260 --> 06:20:59,260
misconceptions about the position of
8748
06:21:00,660 --> 06:21:01,660
relationships of certain protocols
8749
06:21:02,218 --> 06:21:03,218
within the OSI model because these are
8750
06:21:04,378 --> 06:21:05,378
very two very different designs and they
8751
06:21:06,718 --> 06:21:07,718
have different purposes there are some
8752
06:21:09,180 --> 06:21:10,180
recognizable similarities but they're
8753
06:21:11,100 --> 06:21:12,100
still at their core different so the
8754
06:21:13,500 --> 06:21:14,500
purpose of this OSI model was an attempt
8755
06:21:15,718 --> 06:21:16,718
to simplify and standardize networking
8756
06:21:19,100 --> 06:21:20,100
tcp's original purpose as opposed to the
8757
06:21:21,480 --> 06:21:22,480
OSI is more attempting to sort of uh
8758
06:21:25,020 --> 06:21:26,020
sort out the internet protocols into
8759
06:21:27,360 --> 06:21:28,360
comprehensive groups according to their
8760
06:21:29,638 --> 06:21:30,638
functions of the scope and the sort of
8761
06:21:32,100 --> 06:21:33,100
network that's involved
8762
06:21:33,780 --> 06:21:34,780
now one of the similarities between the
8763
06:21:36,240 --> 06:21:37,240
two models is they both have
8764
06:21:37,320 --> 06:21:38,320
interchangeable Network and transport
8765
06:21:39,420 --> 06:21:40,420
layers
8766
06:21:40,440 --> 06:21:41,440
also each layer of the OSI model
8767
06:21:42,420 --> 06:21:43,420
directly correlates with the TCP model
8768
06:21:44,940 --> 06:21:45,940
and here you can see the application
8769
06:21:46,620 --> 06:21:47,620
layer the presentation layer and the
8770
06:21:49,020 --> 06:21:50,020
session layer of the OSI model
8771
06:21:50,638 --> 06:21:51,638
correspond to what we know as the
8772
06:21:52,378 --> 06:21:53,378
application layer of the TCP stack this
8773
06:21:55,320 --> 06:21:56,320
means that everything in the OSI model
8774
06:21:57,058 --> 06:21:58,058
that fell into application presentation
8775
06:21:59,100 --> 06:22:00,100
session are actually done in the
8776
06:22:01,920 --> 06:22:02,920
application support block
8777
06:22:04,320 --> 06:22:05,320
next the transport layer of the OSI
8778
06:22:06,900 --> 06:22:07,900
model corresponds directly to the
8779
06:22:08,280 --> 06:22:09,280
transport layer of the TCP model the
8780
06:22:10,740 --> 06:22:11,740
network layer of OSI with the internet
8781
06:22:12,480 --> 06:22:13,480
layer of tcpip and that is easy to
8782
06:22:15,718 --> 06:22:16,718
remember since internet is really short
8783
06:22:18,058 --> 06:22:19,058
for like internet working
8784
06:22:20,218 --> 06:22:21,218
and the data link and physical layers of
8785
06:22:23,458 --> 06:22:24,458
the OSI model correspond directly to the
8786
06:22:25,680 --> 06:22:26,680
network interface layer of the TCP now
8787
06:22:28,320 --> 06:22:29,320
some of these correlations it should be
8788
06:22:30,058 --> 06:22:31,058
mentioned aren't precise and exact
8789
06:22:32,340 --> 06:22:33,340
they're sort of
8790
06:22:34,280 --> 06:22:35,280
approximations and that's because they
8791
06:22:36,298 --> 06:22:37,298
are two very different models and
8792
06:22:38,218 --> 06:22:39,218
therefore they were created differently
8793
06:22:39,660 --> 06:22:40,660
and weren't necessarily created with the
8794
06:22:41,638 --> 06:22:42,638
one or the other in mind that being said
8795
06:22:43,500 --> 06:22:44,500
tcpip and OSI were built with knowledge
8796
06:22:45,900 --> 06:22:46,900
of one another and so we do see this
8797
06:22:48,000 --> 06:22:49,000
overlap now the TCP model outlines and
8798
06:22:51,718 --> 06:22:52,718
defines the methods data is going to
8799
06:22:54,058 --> 06:22:55,058
flow and commute in a communication
8800
06:22:55,500 --> 06:22:56,500
system it does this by assigning each
8801
06:22:58,200 --> 06:22:59,200
layer in the stack specific functions to
8802
06:23:01,260 --> 06:23:02,260
perform on the data and ultimately each
8803
06:23:03,958 --> 06:23:04,958
layer is completely independent of all
8804
06:23:05,878 --> 06:23:06,878
the other layers and more or less is
8805
06:23:07,798 --> 06:23:08,798
unaware of the other layers
8806
06:23:09,540 --> 06:23:10,540
for instance the topmost layer of the
8807
06:23:11,520 --> 06:23:12,520
application layer is going to perform
8808
06:23:13,500 --> 06:23:14,500
its operations if the processes on the
8809
06:23:16,320 --> 06:23:17,320
communicating systems are directly
8810
06:23:18,660 --> 06:23:19,660
connected to each other by some sort of
8811
06:23:20,580 --> 06:23:21,580
information pipe the operations that
8812
06:23:23,878 --> 06:23:24,878
allow for the next layer the transport
8813
06:23:25,860 --> 06:23:26,860
layer to transmit data between the host
8814
06:23:28,440 --> 06:23:29,440
computers is actually found in the
8815
06:23:30,540 --> 06:23:31,540
protocols of lower layers and from there
8816
06:23:33,958 --> 06:23:34,958
on each data layer will complete its
8817
06:23:37,320 --> 06:23:38,320
specified actions to the data and then
8818
06:23:40,020 --> 06:23:41,020
encapsulate the data where it's then
8819
06:23:42,000 --> 06:23:43,000
passed down the stack in the opposite
8820
06:23:45,240 --> 06:23:46,240
direction when data is traveling back up
8821
06:23:48,480 --> 06:23:49,480
the stack and we saw the same thing with
8822
06:23:50,218 --> 06:23:51,218
OSI model the data is then
8823
06:23:52,878 --> 06:23:53,878
de-encapsulated so when it's going down
8824
06:23:55,320 --> 06:23:56,320
we call that
8825
06:23:57,360 --> 06:23:58,360
being encapsulated
8826
06:24:01,558 --> 06:24:02,558
and when it's going back up we call it
8827
06:24:03,958 --> 06:24:04,958
D encapsulated so we really need to
8828
06:24:06,420 --> 06:24:07,420
understand how all of this works
8829
06:24:08,040 --> 06:24:09,040
together in order to get a really strong
8830
06:24:11,760 --> 06:24:12,760
picture of uh uh TCP and be able to
8831
06:24:16,080 --> 06:24:17,080
speak about the layers in general
8832
06:24:19,378 --> 06:24:20,378
so let's talk about encapsulation each
8833
06:24:22,200 --> 06:24:23,200
layer is responsible for only the
8834
06:24:24,718 --> 06:24:25,718
specific data defined at that layer as
8835
06:24:26,760 --> 06:24:27,760
we've said now these layers are going to
8836
06:24:29,040 --> 06:24:30,040
receive the data package from the layer
8837
06:24:31,080 --> 06:24:32,080
above it when sending and the layer
8838
06:24:33,600 --> 06:24:34,600
below it when receiving this makes sense
8839
06:24:36,298 --> 06:24:37,298
if I'm receiving data is going up so the
8840
06:24:39,298 --> 06:24:40,298
data is coming from below and if I'm
8841
06:24:41,400 --> 06:24:42,400
sending it's going down from the
8842
06:24:43,080 --> 06:24:44,080
application down to the networking
8843
06:24:44,760 --> 06:24:45,760
interface
8844
06:24:46,080 --> 06:24:47,080
now when it receives this package each
8845
06:24:48,718 --> 06:24:49,718
layer is going to add its own packaging
8846
06:24:50,760 --> 06:24:51,760
which is called a header this header is
8847
06:24:53,280 --> 06:24:54,280
used by the corresponding layer at the
8848
06:24:55,920 --> 06:24:56,920
receiving side for specific purposes the
8849
06:24:59,040 --> 06:25:00,040
exact purpose is really going to depend
8850
06:25:00,360 --> 06:25:01,360
on the layer in question but this header
8851
06:25:02,520 --> 06:25:03,520
is going to be added to the beginning of
8852
06:25:04,320 --> 06:25:05,320
the data so that it is the first thing
8853
06:25:06,958 --> 06:25:07,958
received by the receiving layer that way
8854
06:25:10,020 --> 06:25:11,020
each layer on the receiving end can then
8855
06:25:12,120 --> 06:25:13,120
remove that header perform its
8856
06:25:14,280 --> 06:25:15,280
operations and then pass the remaining
8857
06:25:15,900 --> 06:25:16,900
data up the stack up the TCP model on
8858
06:25:19,138 --> 06:25:20,138
the lowest layer a footer is also going
8859
06:25:21,840 --> 06:25:22,840
to be added
8860
06:25:22,980 --> 06:25:23,980
and this is going to add to the frame by
8861
06:25:25,440 --> 06:25:26,440
adding more supplemental information
8862
06:25:27,138 --> 06:25:28,138
this extra data
8863
06:25:29,638 --> 06:25:30,638
at the end of the data package is going
8864
06:25:31,920 --> 06:25:32,920
to assist the receiving end on ensuring
8865
06:25:34,200 --> 06:25:35,200
that the data was received completely
8866
06:25:36,718 --> 06:25:37,718
and undamaged this footer is also what's
8867
06:25:39,540 --> 06:25:40,540
called an FCS or a frame
8868
06:25:45,000 --> 06:25:46,000
check
8869
06:25:48,000 --> 06:25:49,000
sequence
8870
06:25:50,638 --> 06:25:51,638
and as the name implies it is going to
8871
06:25:53,280 --> 06:25:54,280
check to make sure the data was received
8872
06:25:55,500 --> 06:25:56,500
correctly now on the receiving end this
8873
06:25:57,958 --> 06:25:58,958
process is reversed by what's called
8874
06:25:59,820 --> 06:26:00,820
de-encapsulation in other words the data
8875
06:26:02,100 --> 06:26:03,100
is received at each layer and the
8876
06:26:03,480 --> 06:26:04,480
headers are removed to allow the data to
8877
06:26:06,600 --> 06:26:07,600
perform the related tasks where finally
8878
06:26:08,638 --> 06:26:09,638
the data is received by the application
8879
06:26:11,400 --> 06:26:12,400
uh the application layer and then the
8880
06:26:13,740 --> 06:26:14,740
resulting data is delivered to whatever
8881
06:26:15,420 --> 06:26:16,420
the requested application was now just
8882
06:26:17,520 --> 06:26:18,520
like with the OSI model we'll talk about
8883
06:26:19,440 --> 06:26:20,440
later this application layer doesn't
8884
06:26:20,820 --> 06:26:21,820
mean the actual application itself it's
8885
06:26:22,860 --> 06:26:23,860
simply the layer that provides access to
8886
06:26:25,200 --> 06:26:26,200
the information from an application now
8887
06:26:27,780 --> 06:26:28,780
just like the OSI model there are a few
8888
06:26:29,458 --> 06:26:30,458
mnemonic devices that can be used to
8889
06:26:31,620 --> 06:26:32,620
help in Remembering these layers in
8890
06:26:33,240 --> 06:26:34,240
order and the one that I use the most
8891
06:26:35,040 --> 06:26:36,040
going from the top down is called All
8892
06:26:37,980 --> 06:26:38,980
Things in networking again that's
8893
06:26:40,320 --> 06:26:41,320
application All Transport things
8894
06:26:42,780 --> 06:26:43,780
internet in network interface networking
8895
06:26:46,080 --> 06:26:47,080
so now we have a better understanding of
8896
06:26:48,000 --> 06:26:49,000
how the data is going to proceed from
8897
06:26:49,860 --> 06:26:50,860
layer to layer through encapsulation
8898
06:26:52,200 --> 06:26:53,200
going down from application to transport
8899
06:26:55,378 --> 06:26:56,378
to internet to network interface right
8900
06:26:58,920 --> 06:26:59,920
and then through D inter
8901
06:27:00,740 --> 06:27:01,740
de-encapsulation which goes the opposite
8902
06:27:03,000 --> 06:27:04,000
way let's take a closer look at these
8903
06:27:06,180 --> 06:27:07,180
layers starting with the topmost layer
8904
06:27:08,100 --> 06:27:09,100
the application layer so here on the
8905
06:27:10,860 --> 06:27:11,860
application layer much like the
8906
06:27:12,660 --> 06:27:13,660
application layer of the OSI model we
8907
06:27:15,000 --> 06:27:16,000
find what's considered the highest level
8908
06:27:16,920 --> 06:27:17,920
protocols higher level meaning these
8909
06:27:19,320 --> 06:27:20,320
protocols such as SMTP FTP and so on
8910
06:27:23,040 --> 06:27:24,040
these Protocols are not necessarily
8911
06:27:25,260 --> 06:27:26,260
concerned with the method by which the
8912
06:27:27,958 --> 06:27:28,958
data arrives at it says destination but
8913
06:27:30,420 --> 06:27:31,420
simply that it just arrives period
8914
06:27:33,000 --> 06:27:34,000
here in the application layer we also
8915
06:27:35,100 --> 06:27:36,100
provide the functions that relate to the
8916
06:27:37,620 --> 06:27:38,620
presentation and the session layers of
8917
06:27:40,320 --> 06:27:41,320
the OSI model as we've already pointed
8918
06:27:42,540 --> 06:27:43,540
out it does this typically through the
8919
06:27:44,638 --> 06:27:45,638
use of what are called libraries
8920
06:27:49,020 --> 06:27:50,020
which are collections of Behavioral
8921
06:27:52,620 --> 06:27:53,620
implementations that can be utilized and
8922
06:27:56,160 --> 06:27:57,160
called upon by services that are
8923
06:27:58,378 --> 06:27:59,378
unrelated
8924
06:27:59,638 --> 06:28:00,638
so this means that the application layer
8925
06:28:02,878 --> 06:28:03,878
of the TCP model
8926
06:28:05,100 --> 06:28:06,100
encodes the data and performs any
8927
06:28:08,280 --> 06:28:09,280
encryption and compression that's
8928
06:28:10,200 --> 06:28:11,200
necessary
8929
06:28:11,520 --> 06:28:12,520
as well as initiating and maintaining
8930
06:28:15,420 --> 06:28:16,420
the connection or the session as we can
8931
06:28:18,240 --> 06:28:19,240
see here these are just some of the
8932
06:28:20,340 --> 06:28:21,340
protocols that we find at the
8933
06:28:22,620 --> 06:28:23,620
application layer we can also further
8934
06:28:25,260 --> 06:28:26,260
group some of these applications based
8935
06:28:27,120 --> 06:28:28,120
on the specific type of function that
8936
06:28:29,100 --> 06:28:30,100
they provide for instance if we're
8937
06:28:31,860 --> 06:28:32,860
looking at protocols that are dedicated
8938
06:28:34,100 --> 06:28:35,100
to transferring files such as FTP or
8939
06:28:39,000 --> 06:28:40,000
tftp which of your call is the trivial
8940
06:28:41,820 --> 06:28:42,820
FTP then there are also protocols that
8941
06:28:45,058 --> 06:28:46,058
can be categorized by supporting
8942
06:28:46,680 --> 06:28:47,680
services so some of those are going to
8943
06:28:49,440 --> 06:28:50,440
be for instance DNS the domain name
8944
06:28:51,480 --> 06:28:52,480
service
8945
06:28:52,860 --> 06:28:53,860
and SNMP which is for management
8946
06:28:55,320 --> 06:28:56,320
purposes
8947
06:28:57,980 --> 06:28:58,980
or even boot P or the bootstrap protocol
8948
06:29:01,860 --> 06:29:02,860
now just like the OSI models application
8949
06:29:04,680 --> 06:29:05,680
layer this tcpip application layer is
8950
06:29:07,558 --> 06:29:08,558
responsible for process to process level
8951
06:29:11,218 --> 06:29:12,218
data communication this means that the
8952
06:29:14,400 --> 06:29:15,400
application itself doesn't necessarily
8953
06:29:16,558 --> 06:29:17,558
reside on this layer
8954
06:29:18,420 --> 06:29:19,420
what more means is that it defines what
8955
06:29:21,120 --> 06:29:22,120
the application or what type of
8956
06:29:22,558 --> 06:29:23,558
application can be utilized depending on
8957
06:29:26,040 --> 06:29:27,040
the protocol so for example SMTP
8958
06:29:28,700 --> 06:29:29,700
specifies that outgoing mail
8959
06:29:30,780 --> 06:29:31,780
communication with the mail or exchange
8960
06:29:32,580 --> 06:29:33,580
server and IMAP specifies the incoming
8961
06:29:35,760 --> 06:29:36,760
mail communication with the mail server
8962
06:29:37,500 --> 06:29:38,500
also remember that only those
8963
06:29:40,138 --> 06:29:41,138
applications that are network relatable
8964
06:29:42,540 --> 06:29:43,540
are going to be managed this layer not
8965
06:29:45,420 --> 06:29:46,420
necessarily all application so this
8966
06:29:48,480 --> 06:29:49,480
layer's role is more towards software
8967
06:29:51,000 --> 06:29:52,000
applications and protocols and their
8968
06:29:52,920 --> 06:29:53,920
interaction with the user it's not as
8969
06:29:55,378 --> 06:29:56,378
concerned with the formatting or
8970
06:29:57,298 --> 06:29:58,298
transmitting the data across the media
8971
06:30:00,240 --> 06:30:01,240
for that we have to move lower down into
8972
06:30:02,820 --> 06:30:03,820
the model and get to the transport layer
8973
06:30:06,360 --> 06:30:07,360
now on the transport layer of the tcpip
8974
06:30:09,000 --> 06:30:10,000
model we have two main protocols that we
8975
06:30:11,638 --> 06:30:12,638
need to be familiar with first we have
8976
06:30:14,100 --> 06:30:15,100
the transmission control protocol or TCP
8977
06:30:18,360 --> 06:30:19,360
and the second is the user datagram
8978
06:30:20,940 --> 06:30:21,940
protocol or UDP let me just write those
8979
06:30:23,878 --> 06:30:24,878
out here so that you can see what these
8980
06:30:26,400 --> 06:30:27,400
stand for again
8981
06:30:41,580 --> 06:30:42,580
now on this layer three things are going
8982
06:30:43,860 --> 06:30:44,860
on
8983
06:30:44,700 --> 06:30:45,700
uh data verification
8984
06:30:54,900 --> 06:30:55,900
error checking
8985
06:31:07,500 --> 06:31:08,500
and flow control
8986
06:31:11,820 --> 06:31:12,820
now our two heavy hitting Protocols are
8987
06:31:14,820 --> 06:31:15,820
done in very different ways so tcpap as
8988
06:31:18,958 --> 06:31:19,958
we've talked about in the past is what
8989
06:31:20,458 --> 06:31:21,458
we call connection
8990
06:31:21,680 --> 06:31:22,680
oriented which means there's a
8991
06:31:23,820 --> 06:31:24,820
guaranteed delivery whereas UDP is
8992
06:31:27,120 --> 06:31:28,120
connection last which means it's just a
8993
06:31:28,980 --> 06:31:29,980
best effort delivery
8994
06:31:31,200 --> 06:31:32,200
UDP doesn't have any means of error
8995
06:31:33,240 --> 06:31:34,240
checking that's one of tcp's areas of
8996
06:31:35,760 --> 06:31:36,760
expertise so to put TCP and UDP in
8997
06:31:38,340 --> 06:31:39,340
perspective I've always thought about it
8998
06:31:40,020 --> 06:31:41,020
as if say a grade school teacher needs
8999
06:31:42,360 --> 06:31:43,360
to send a note to a student's parent
9000
06:31:43,798 --> 06:31:44,798
because the student hadn't turned in
9001
06:31:45,900 --> 06:31:46,900
their homework for more than a week now
9002
06:31:47,878 --> 06:31:48,878
the teacher can send the note one of two
9003
06:31:49,680 --> 06:31:50,680
ways the first is through UDP or the
9004
06:31:53,360 --> 06:31:54,360
uninterested doubtful pre-teen now this
9005
06:31:57,058 --> 06:31:58,058
UDP is certainly going to make it home
9006
06:31:58,740 --> 06:31:59,740
as quickly as possible but whether the
9007
06:32:00,900 --> 06:32:01,900
message gets sent to the parent or not
9008
06:32:02,520 --> 06:32:03,520
it really isn't udp's biggest concern
9009
06:32:04,798 --> 06:32:05,798
getting there quickly is so UDP is going
9010
06:32:08,160 --> 06:32:09,160
to have you that quick
9011
06:32:09,840 --> 06:32:10,840
but not necessarily guaranteed now
9012
06:32:13,138 --> 06:32:14,138
meanwhile the other method TCP or
9013
06:32:15,660 --> 06:32:16,660
Teacher Calls parent this is the way the
9014
06:32:18,718 --> 06:32:19,718
teacher has a guaranteed delivery of the
9015
06:32:20,760 --> 06:32:21,760
message the parents aren't home the
9016
06:32:23,100 --> 06:32:24,100
message cannot be delivered or something
9017
06:32:24,780 --> 06:32:25,780
happens during the communication process
9018
06:32:27,200 --> 06:32:28,200
TCP will wait and attempt to send the
9019
06:32:29,820 --> 06:32:30,820
message again
9020
06:32:31,020 --> 06:32:32,020
so whereas TCP
9021
06:32:34,138 --> 06:32:35,138
UDP is quick TCP is guaranteed
9022
06:32:37,740 --> 06:32:38,740
and so that's sort of the give and take
9023
06:32:39,360 --> 06:32:40,360
there
9024
06:32:40,378 --> 06:32:41,378
now while our story is a generalization
9025
06:32:42,540 --> 06:32:43,540
it really touches on the two most
9026
06:32:44,458 --> 06:32:45,458
important characteristics of these
9027
06:32:46,080 --> 06:32:47,080
protocols now there are a few other uh
9028
06:32:49,500 --> 06:32:50,500
specifics about TCP that are are really
9029
06:32:52,020 --> 06:32:53,020
worth mentioning firstly and most
9030
06:32:54,180 --> 06:32:55,180
importantly we have reliability like we
9031
06:32:57,180 --> 06:32:58,180
just mentioned how it accomplishes this
9032
06:32:59,100 --> 06:33:00,100
is TCP assigns a sequence numbers to
9033
06:33:02,760 --> 06:33:03,760
each segment of data and the receiving
9034
06:33:04,500 --> 06:33:05,500
end looks for these sequence numbers and
9035
06:33:06,718 --> 06:33:07,718
sends what's called an ack or
9036
06:33:08,760 --> 06:33:09,760
acknowledgment message
9037
06:33:10,558 --> 06:33:11,558
which is something important that you do
9038
06:33:12,540 --> 06:33:13,540
want to
9039
06:33:13,798 --> 06:33:14,798
um
9040
06:33:14,458 --> 06:33:15,458
be familiar with and you might also see
9041
06:33:16,500 --> 06:33:17,500
that as a
9042
06:33:17,700 --> 06:33:18,700
sin act which is the synchronization and
9043
06:33:21,180 --> 06:33:22,180
that act message is sent when the data
9044
06:33:22,920 --> 06:33:23,920
is successfully received now the sending
9045
06:33:25,260 --> 06:33:26,260
transport layer doesn't receive the
9046
06:33:27,360 --> 06:33:28,360
accurate acknowledgment message then
9047
06:33:29,400 --> 06:33:30,400
it's going to re-transmit the Lost
9048
06:33:31,020 --> 06:33:32,020
segment secondly we have data flow
9049
06:33:33,780 --> 06:33:34,780
control which is we've already mentioned
9050
06:33:35,760 --> 06:33:36,760
this is important in as networking
9051
06:33:38,160 --> 06:33:39,160
devices are not always going to operate
9052
06:33:40,980 --> 06:33:41,980
at the same speeds and without flow
9053
06:33:43,080 --> 06:33:44,080
control slower devices might overrun by
9054
06:33:46,080 --> 06:33:47,080
might be overrun with data causing
9055
06:33:48,600 --> 06:33:49,600
Network downtime thirdly we have
9056
06:33:51,180 --> 06:33:52,180
something called segmentation and
9057
06:33:53,400 --> 06:33:54,400
segmentation occurs at this layer taking
9058
06:33:55,680 --> 06:33:56,680
the tedious task away from the
9059
06:33:58,200 --> 06:33:59,200
application layer of sectioning the data
9060
06:34:00,540 --> 06:34:01,540
into pieces or segments these segments
9061
06:34:03,360 --> 06:34:04,360
can then get sent to the next layer
9062
06:34:05,340 --> 06:34:06,340
below to be prepared for transmittal
9063
06:34:07,798 --> 06:34:08,798
across the media so the final
9064
06:34:10,378 --> 06:34:11,378
consideration for TCP is in order for an
9065
06:34:13,320 --> 06:34:14,320
application to be able to utilize this
9066
06:34:15,540 --> 06:34:16,540
protocol a connection between port
9067
06:34:18,480 --> 06:34:19,480
numbers has to be established the
9068
06:34:20,760 --> 06:34:21,760
devices try to create this session using
9069
06:34:22,740 --> 06:34:23,740
a combination of an IP address and a
9070
06:34:26,340 --> 06:34:27,340
port number now this combination is
9071
06:34:28,620 --> 06:34:29,620
called a socket
9072
06:34:30,600 --> 06:34:31,600
in the future modules we're going to
9073
06:34:32,280 --> 06:34:33,280
look at at referencing TCP and UDP as
9074
06:34:35,160 --> 06:34:36,160
well as going a bit more further into
9075
06:34:36,780 --> 06:34:37,780
explaining how they function and
9076
06:34:38,638 --> 06:34:39,638
interact with different protocols but
9077
06:34:40,558 --> 06:34:41,558
what you see here is the IP address
9078
06:34:45,480 --> 06:34:46,480
on a specific port number so we know
9079
06:34:48,540 --> 06:34:49,540
based on this port number what the
9080
06:34:51,900 --> 06:34:52,900
connection
9081
06:34:53,280 --> 06:34:54,280
is trying to attempt and whether or not
9082
06:34:55,440 --> 06:34:56,440
it's TCP or UDP we know whether it's
9083
06:34:57,298 --> 06:34:58,298
connection oriented or connection less
9084
06:35:00,020 --> 06:35:01,020
the internet layer of the tcpip model
9085
06:35:03,240 --> 06:35:04,240
corresponds directly to the network
9086
06:35:05,700 --> 06:35:06,700
layer of the OSI model now the data
9087
06:35:08,820 --> 06:35:09,820
terminology on this layer as I think we
9088
06:35:11,160 --> 06:35:12,160
discussed when we talked about the OSI
9089
06:35:12,780 --> 06:35:13,780
model is a datagram
9090
06:35:16,440 --> 06:35:17,440
now as the internet layer relates
9091
06:35:18,840 --> 06:35:19,840
directly to the network layer which if
9092
06:35:20,940 --> 06:35:21,940
you recall
9093
06:35:21,958 --> 06:35:22,958
was layer three we can a little more
9094
06:35:24,958 --> 06:35:25,958
easily understand a few things that
9095
06:35:26,700 --> 06:35:27,700
happen on this layer first it tells us
9096
06:35:29,160 --> 06:35:30,160
that this layer is responsible for
9097
06:35:31,798 --> 06:35:32,798
routing if you recall layer 3 devices
9098
06:35:34,798 --> 06:35:35,798
for OSI are routers
9099
06:35:39,900 --> 06:35:40,900
this means that it ensures the typically
9100
06:35:43,320 --> 06:35:44,320
fastest and best path from the source to
9101
06:35:47,100 --> 06:35:48,100
the destination
9102
06:35:48,480 --> 06:35:49,480
this layer is also responsible for data
9103
06:35:51,000 --> 06:35:52,000
addressing and if you recall with data
9104
06:35:53,400 --> 06:35:54,400
addressing we're dealing with the second
9105
06:35:54,958 --> 06:35:55,958
part of TCP IP which is the internet
9106
06:36:01,558 --> 06:36:02,558
protocol aptly name send is since it is
9107
06:36:04,860 --> 06:36:05,860
on the internet layer and the Internet
9108
06:36:07,080 --> 06:36:08,080
Protocol is responsible for a couple
9109
06:36:08,700 --> 06:36:09,700
main functions the first of those
9110
06:36:11,218 --> 06:36:12,218
functions is what we call fragmentation
9111
06:36:13,920 --> 06:36:14,920
it's important for us to understand
9112
06:36:16,680 --> 06:36:17,680
something called mtus which are maximum
9113
06:36:21,718 --> 06:36:22,718
transmission units
9114
06:36:33,360 --> 06:36:34,360
so that we know why fragmentation has to
9115
06:36:35,820 --> 06:36:36,820
occur now the MTU is the term as the
9116
06:36:39,120 --> 06:36:40,120
name implies that's used to define the
9117
06:36:41,700 --> 06:36:42,700
largest size of increment of data in
9118
06:36:44,700 --> 06:36:45,700
bytes that can pass through the given
9119
06:36:46,860 --> 06:36:47,860
Network device such as a router now
9120
06:36:50,400 --> 06:36:51,400
often data is going to need to pass
9121
06:36:51,958 --> 06:36:52,958
through networks with mtus that are less
9122
06:36:55,500 --> 06:36:56,500
than
9123
06:36:56,580 --> 06:36:57,580
the MTU listed on that device
9124
06:37:00,298 --> 06:37:01,298
generally even uh not just match two but
9125
06:37:03,360 --> 06:37:04,360
the lower it is the more it's preferred
9126
06:37:05,458 --> 06:37:06,458
because then we can make sure that it's
9127
06:37:07,080 --> 06:37:08,080
not going to have a problem so network
9128
06:37:08,638 --> 06:37:09,638
devices are going to send and receive
9129
06:37:10,620 --> 06:37:11,620
messages or responses to datagrams that
9130
06:37:14,820 --> 06:37:15,820
are larger than the device's MTU
9131
06:37:17,700 --> 06:37:18,700
in these instances when there is a
9132
06:37:19,620 --> 06:37:20,620
datagram that's larger than the MTU of a
9133
06:37:21,840 --> 06:37:22,840
device the transmitting internet layer
9134
06:37:25,638 --> 06:37:26,638
fragments the data or the datagram and
9135
06:37:29,280 --> 06:37:30,280
then tries to resend it
9136
06:37:32,700 --> 06:37:33,700
in smaller and more easily manageable
9137
06:37:35,638 --> 06:37:36,638
blocks
9138
06:37:36,718 --> 06:37:37,718
so once the data is fragmented enough to
9139
06:37:39,180 --> 06:37:40,180
pass through the remaining devices the
9140
06:37:41,700 --> 06:37:42,700
receiving ends internet layer then
9141
06:37:43,620 --> 06:37:44,620
pieces together those fragments during
9142
06:37:46,320 --> 06:37:47,320
the reassembly process now in the header
9143
06:37:49,500 --> 06:37:50,500
of those fragmented datagrams if we go
9144
06:37:51,420 --> 06:37:52,420
back just a bit you'll see right here
9145
06:37:53,700 --> 06:37:54,700
the header
9146
06:37:55,860 --> 06:37:56,860
there is a specific field that's set
9147
06:37:57,360 --> 06:37:58,360
aside for what we call three flag bits
9148
06:38:03,240 --> 06:38:04,240
the first flag bit is reserved and
9149
06:38:05,280 --> 06:38:06,280
should always be zero the second is the
9150
06:38:08,218 --> 06:38:09,218
don't fragment or the DF bit now either
9151
06:38:10,798 --> 06:38:11,798
this bit is off or zero which means
9152
06:38:13,200 --> 06:38:14,200
fragment this datagram or on meaning
9153
06:38:15,660 --> 06:38:16,660
don't fragment this datagram the third
9154
06:38:18,120 --> 06:38:19,120
flag bit is the more fragments bit
9155
06:38:21,840 --> 06:38:22,840
MF
9156
06:38:23,580 --> 06:38:24,580
and when this is on it means that there
9157
06:38:25,798 --> 06:38:26,798
are more fragments on the way
9158
06:38:27,900 --> 06:38:28,900
and finally when the MF flag is off it
9159
06:38:29,820 --> 06:38:30,820
means there are no more fragments to be
9160
06:38:31,620 --> 06:38:32,620
sent as you can see right here
9161
06:38:33,958 --> 06:38:34,958
and that there were never any fragments
9162
06:38:35,760 --> 06:38:36,760
to send so as we see here our initial
9163
06:38:37,558 --> 06:38:38,558
datagram that we wanted to transmit
9164
06:38:41,940 --> 06:38:42,940
had an MTU that was too large to send it
9165
06:38:47,040 --> 06:38:48,040
was
9166
06:38:47,840 --> 06:38:48,840
2500 and it was too large therefore to
9167
06:38:50,760 --> 06:38:51,760
go through router B and so then we
9168
06:38:52,740 --> 06:38:53,740
fragmented this datagram and added those
9169
06:38:55,020 --> 06:38:56,020
bits to the headers of the fragments
9170
06:38:57,600 --> 06:38:58,600
so that's how this all works and that's
9171
06:39:00,660 --> 06:39:01,660
why fragmenting is so important now
9172
06:39:02,820 --> 06:39:03,820
let's take a look at a networking
9173
06:39:04,260 --> 06:39:05,260
problem that used to plague Network
9174
06:39:05,878 --> 06:39:06,878
engineers and technicians that has to do
9175
06:39:07,920 --> 06:39:08,920
with mtus for some time this is also
9176
06:39:10,260 --> 06:39:11,260
something that's specifically called for
9177
06:39:11,878 --> 06:39:12,878
on the network plus exam now a black
9178
06:39:14,400 --> 06:39:15,400
hole router is the name given to a
9179
06:39:16,620 --> 06:39:17,620
situation where a datagram is sent with
9180
06:39:19,500 --> 06:39:20,500
an MTU that's greater than the MTU of
9181
06:39:22,558 --> 06:39:23,558
the receiving device as we can see here
9182
06:39:26,040 --> 06:39:27,040
now when the destination device is
9183
06:39:28,260 --> 06:39:29,260
unable to receive the IP datagram
9184
06:39:31,200 --> 06:39:32,200
it's supposed to send a specific icmp
9185
06:39:34,620 --> 06:39:35,620
response that notifies the transmitting
9186
06:39:37,620 --> 06:39:38,620
station that there's an MTU mismatch
9187
06:39:40,798 --> 06:39:41,798
this can be due to a variety of reasons
9188
06:39:43,920 --> 06:39:44,920
one of which could be as simple as a
9189
06:39:47,160 --> 06:39:48,160
firewall that's blocking the icmp
9190
06:39:49,620 --> 06:39:50,620
response and by the way when we talk
9191
06:39:51,780 --> 06:39:52,780
about icmp we're really talking about
9192
06:39:54,480 --> 06:39:55,480
the ping utility as well now in these
9193
06:39:57,420 --> 06:39:58,420
cases this is called a black hole
9194
06:39:59,458 --> 06:40:00,458
because of The Disappearance of
9195
06:40:00,958 --> 06:40:01,958
datagrams basically as you can see I'm
9196
06:40:03,360 --> 06:40:04,360
sending the data
9197
06:40:05,160 --> 06:40:06,160
the data gets here the device the router
9198
06:40:07,740 --> 06:40:08,740
here says wait a minute I can't fit that
9199
06:40:09,480 --> 06:40:10,480
2500 MTU through my 1500 sends a
9200
06:40:12,660 --> 06:40:13,660
response but for some reason the
9201
06:40:14,340 --> 06:40:15,340
response
9202
06:40:15,718 --> 06:40:16,718
hits this firewall and doesn't make it
9203
06:40:18,000 --> 06:40:19,000
back to the router and so the data is
9204
06:40:20,520 --> 06:40:21,520
lost into this black hole now this is
9205
06:40:23,940 --> 06:40:24,940
called a black hole because this
9206
06:40:25,740 --> 06:40:26,740
datagram disappears as if it were sucked
9207
06:40:29,100 --> 06:40:30,100
into a black hole now there are some
9208
06:40:30,958 --> 06:40:31,958
ways to detect or find this MTU black
9209
06:40:33,480 --> 06:40:34,480
hole and one of the best ways is to use
9210
06:40:36,180 --> 06:40:37,180
the Ping utility and specify a syntax
9211
06:40:39,798 --> 06:40:40,798
that sets the MTU of the icmp echo
9212
06:40:43,860 --> 06:40:44,860
request meaning you tell it I want to
9213
06:40:46,320 --> 06:40:47,320
Ping with this much of an MTU and so
9214
06:40:49,260 --> 06:40:50,260
then we can see if the Ping's not coming
9215
06:40:51,000 --> 06:40:52,000
back if it's coming back at one MTU and
9216
06:40:52,620 --> 06:40:53,620
not another then we know oh this is
9217
06:40:54,718 --> 06:40:55,718
what's happening right here and we can
9218
06:40:56,580 --> 06:40:57,580
determine uh where the black hole is
9219
06:40:59,100 --> 06:41:00,100
specifically occurring
9220
06:41:01,020 --> 06:41:02,020
now on the bottom of the tcpip stack is
9221
06:41:03,900 --> 06:41:04,900
the network interface layer now this
9222
06:41:07,080 --> 06:41:08,080
layer is completely dedicated to the
9223
06:41:10,020 --> 06:41:11,020
actual transfer of bits across the
9224
06:41:12,540 --> 06:41:13,540
network medium the network interface
9225
06:41:15,000 --> 06:41:16,000
layer of the tcpip model directly
9226
06:41:17,878 --> 06:41:18,878
correlates to the physical
9227
06:41:22,500 --> 06:41:23,500
and the data link layer
9228
06:41:28,378 --> 06:41:29,378
of the OSI model
9229
06:41:32,040 --> 06:41:33,040
now the data type we're going to be
9230
06:41:33,718 --> 06:41:34,718
talking about on this layer are what we
9231
06:41:35,760 --> 06:41:36,760
call frames as opposed to datagrams
9232
06:41:39,058 --> 06:41:40,058
and the major functions that are
9233
06:41:40,680 --> 06:41:41,680
performed on this layer on the data link
9234
06:41:42,660 --> 06:41:43,660
of the OSI model are also occurring at
9235
06:41:45,660 --> 06:41:46,660
this layer so we're really talking about
9236
06:41:50,218 --> 06:41:51,218
switching operations that occur on Layer
9237
06:41:52,740 --> 06:41:53,740
Two
9238
06:41:53,638 --> 06:41:54,638
which again is that data link layer
9239
06:41:58,080 --> 06:41:59,080
and so this is where we see switches
9240
06:42:00,058 --> 06:42:01,058
operating
9241
06:42:05,700 --> 06:42:06,700
which means that we're really dealing
9242
06:42:07,980 --> 06:42:08,980
with Mac addresses okay now a MAC
9243
06:42:11,580 --> 06:42:12,580
address again is a 48
9244
06:42:16,320 --> 06:42:17,320
bit hexadecimal universally unique
9245
06:42:20,580 --> 06:42:21,580
identifier that's broken up into several
9246
06:42:23,160 --> 06:42:24,160
parts
9247
06:42:24,180 --> 06:42:25,180
first part of it is what we call the oui
9248
06:42:28,080 --> 06:42:29,080
or the organizational
9249
06:42:31,200 --> 06:42:32,200
unique identifier
9250
06:42:33,480 --> 06:42:34,480
this basically says what company
9251
06:42:35,878 --> 06:42:36,878
is uh sending out this device
9252
06:42:39,180 --> 06:42:40,180
and then we have the second part which
9253
06:42:42,298 --> 06:42:43,298
is the Nic specific
9254
06:42:46,020 --> 06:42:47,020
and then we have the second part
9255
06:42:48,298 --> 06:42:49,298
which is specific to that device itself
9256
06:42:52,200 --> 06:42:53,200
so this is the manufacturer
9257
06:42:56,280 --> 06:42:57,280
and this is for the device you can
9258
06:42:58,080 --> 06:42:59,080
literally go online search for this part
9259
06:43:01,500 --> 06:43:02,500
of the MAC address and it'll tell you
9260
06:43:02,760 --> 06:43:03,760
what company is creating this device
9261
06:43:07,620 --> 06:43:08,620
now the easiest way to find the MAC
9262
06:43:09,840 --> 06:43:10,840
address in a Windows PC is by opening up
9263
06:43:12,120 --> 06:43:13,120
the command prompt and using ipconfig
9264
06:43:14,940 --> 06:43:15,940
all which we've talked about in a plus
9265
06:43:18,000 --> 06:43:19,000
this brings up the Internet Protocol
9266
06:43:20,040 --> 06:43:21,040
information the IP address and it also
9267
06:43:22,680 --> 06:43:23,680
brings up the MAC address or the
9268
06:43:25,080 --> 06:43:26,080
physical address that's assigned to your
9269
06:43:26,878 --> 06:43:27,878
Nick
9270
06:43:28,200 --> 06:43:29,200
so now that we've covered the MAC
9271
06:43:29,760 --> 06:43:30,760
address is it's really important to
9272
06:43:31,680 --> 06:43:32,680
understand the parts of an Ethernet
9273
06:43:34,200 --> 06:43:35,200
frame and remember we're talking about
9274
06:43:35,820 --> 06:43:36,820
frames at this juncture
9275
06:43:39,660 --> 06:43:40,660
so the Preamble of an Ethernet frame is
9276
06:43:42,540 --> 06:43:43,540
made up of seven bytes or 56 bits and
9277
06:43:45,360 --> 06:43:46,360
this serves as synchronization
9278
06:43:50,520 --> 06:43:51,520
and gives the receiving station a heads
9279
06:43:52,980 --> 06:43:53,980
up to standby and look out for a signal
9280
06:43:55,020 --> 06:43:56,020
that's coming
9281
06:43:56,100 --> 06:43:57,100
the next part is what we call the start
9282
06:43:58,200 --> 06:43:59,200
of frame delimiter the only purpose of
9283
06:44:00,958 --> 06:44:01,958
this is to indicate the start of data
9284
06:44:03,660 --> 06:44:04,660
the next two parts are the source and
9285
06:44:05,700 --> 06:44:06,700
destination Mac addresses so the
9286
06:44:09,180 --> 06:44:10,180
ethernet frame again this is everything
9287
06:44:11,400 --> 06:44:12,400
that's going over this ethernet uh over
9288
06:44:14,878 --> 06:44:15,878
the network we have the Preamble it says
9289
06:44:17,280 --> 06:44:18,280
Hey pay attention now this that says now
9290
06:44:20,638 --> 06:44:21,638
I'm giving you some data and then we
9291
06:44:22,378 --> 06:44:23,378
have the destination and the source Mac
9292
06:44:24,540 --> 06:44:25,540
addresses so that way we know where it's
9293
06:44:27,000 --> 06:44:28,000
coming from who it's going to and this
9294
06:44:29,580 --> 06:44:30,580
takes up 96 bits
9295
06:44:35,100 --> 06:44:36,100
or 12 bytes
9296
06:44:38,820 --> 06:44:39,820
because remember this is 48 bits right
9297
06:44:41,100 --> 06:44:42,100
here so if we double that that's going
9298
06:44:43,080 --> 06:44:44,080
to be 96 and then the next type is
9299
06:44:45,540 --> 06:44:46,540
What's called the frame type this is two
9300
06:44:48,360 --> 06:44:49,360
uh bytes that contain either the client
9301
06:44:52,260 --> 06:44:53,260
protocol information or the number of
9302
06:44:54,840 --> 06:44:55,840
bytes that are found in the data field
9303
06:44:56,340 --> 06:44:57,340
which happen to be the next part of the
9304
06:44:58,080 --> 06:44:59,080
frame
9305
06:44:59,160 --> 06:45:00,160
which is the data this field is going to
9306
06:45:01,920 --> 06:45:02,920
be a certain number of bytes and the
9307
06:45:04,378 --> 06:45:05,378
amount of data is going to change with
9308
06:45:06,120 --> 06:45:07,120
any given transmission the maximum
9309
06:45:08,580 --> 06:45:09,580
amount of data allowed in this field is
9310
06:45:10,980 --> 06:45:11,980
1500 bytes we can't have more than that
9311
06:45:14,040 --> 06:45:15,040
now if this field is any less than 46
9312
06:45:16,798 --> 06:45:17,798
bytes then we have to actually have
9313
06:45:19,080 --> 06:45:20,080
something called a pad which is actually
9314
06:45:21,360 --> 06:45:22,360
just going to be used to fill in the
9315
06:45:23,340 --> 06:45:24,340
rest of the data
9316
06:45:24,718 --> 06:45:25,718
and the final part of this ethernet
9317
06:45:26,400 --> 06:45:27,400
frame is called the FCS or the frame
9318
06:45:34,138 --> 06:45:35,138
check sequence and this is used for
9319
06:45:36,600 --> 06:45:37,600
cyclic redundancy check which is also
9320
06:45:38,760 --> 06:45:39,760
called CRC this basically allows us to
9321
06:45:41,700 --> 06:45:42,700
make sure that there are no errors in
9322
06:45:43,558 --> 06:45:44,558
the data now similar to the way that a
9323
06:45:45,900 --> 06:45:46,900
an algorithm is going to be used to
9324
06:45:47,760 --> 06:45:48,760
ensure Integrity of data the CRC uses a
9325
06:45:50,638 --> 06:45:51,638
mathematical algorithm which sometimes
9326
06:45:53,100 --> 06:45:54,100
we're going to refer to as hashing which
9327
06:45:54,540 --> 06:45:55,540
we'll talk a lot more about when we get
9328
06:45:56,040 --> 06:45:57,040
to Security Plus
9329
06:45:59,878 --> 06:46:00,878
that's made before the data is sent and
9330
06:46:03,298 --> 06:46:04,298
then it is checked when it gets there
9331
06:46:05,100 --> 06:46:06,100
that way we can compare the two results
9332
06:46:07,020 --> 06:46:08,020
bit for bit and if the two numbers don't
9333
06:46:08,820 --> 06:46:09,820
match then we know the frame needs to be
9334
06:46:10,500 --> 06:46:11,500
discarded we assume there's been a
9335
06:46:12,240 --> 06:46:13,240
transmission error or that there was a
9336
06:46:14,160 --> 06:46:15,160
data Collision of some sort and then we
9337
06:46:16,260 --> 06:46:17,260
ask the data to be resent
9338
06:46:18,240 --> 06:46:19,240
now this layer by the way this network
9339
06:46:19,860 --> 06:46:20,860
interface layer is also responsible for
9340
06:46:22,680 --> 06:46:23,680
the network access control and some of
9341
06:46:25,378 --> 06:46:26,378
the protocols that operate on this are
9342
06:46:28,260 --> 06:46:29,260
what are called uh point to point
9343
06:46:31,700 --> 06:46:32,700
protocols ISDN which is a which we've
9344
06:46:35,218 --> 06:46:36,218
talked about also a type of
9345
06:46:37,440 --> 06:46:38,440
um
9346
06:46:38,100 --> 06:46:39,100
Network and also DSL so these are some
9347
06:46:41,040 --> 06:46:42,040
of the things that exist at this and
9348
06:46:42,958 --> 06:46:43,958
this makes sense because again we're
9349
06:46:44,520 --> 06:46:45,520
dealing with the physical bits bytes of
9350
06:46:46,558 --> 06:46:47,558
data
9351
06:46:47,700 --> 06:46:48,700
so now that we've taken a look at each
9352
06:46:50,218 --> 06:46:51,218
of the layers in the TCP model there's
9353
06:46:52,378 --> 06:46:53,378
still a couple things that we still need
9354
06:46:53,940 --> 06:46:54,940
to Define now we've discussed how some
9355
06:46:56,340 --> 06:46:57,340
of the protocols that we've seen relate
9356
06:46:58,978 --> 06:46:59,978
to the OSI model as well as the tcpip
9357
06:47:01,320 --> 06:47:02,320
model and we found that some of the
9358
06:47:03,058 --> 06:47:04,058
protocols function much more smoothly
9359
06:47:04,860 --> 06:47:05,860
when they're put into the context of an
9360
06:47:06,900 --> 06:47:07,900
outline of one of these models so the
9361
06:47:09,058 --> 06:47:10,058
next definition I want to make sure to
9362
06:47:10,680 --> 06:47:11,680
cover is something called protocol
9363
06:47:12,360 --> 06:47:13,360
binding this is when a network interface
9364
06:47:14,940 --> 06:47:15,940
card receives an assigned protocol it's
9365
06:47:18,420 --> 06:47:19,420
considered binding that protocol to that
9366
06:47:21,298 --> 06:47:22,298
Nick so just we learned how the data is
9367
06:47:23,638 --> 06:47:24,638
going to be passed down from one layer
9368
06:47:25,440 --> 06:47:26,440
to the next it's very important that we
9369
06:47:27,420 --> 06:47:28,420
have these protocols bound to the Nick
9370
06:47:29,638 --> 06:47:30,638
we can have multiple protocols actually
9371
06:47:32,160 --> 06:47:33,160
bound to one network interface card now
9372
06:47:35,520 --> 06:47:36,520
of course the most easily recognized we
9373
06:47:37,680 --> 06:47:38,680
can most easily recognize these when
9374
06:47:39,180 --> 06:47:40,180
we're looking at the ipv4 and IPv6
9375
06:47:41,760 --> 06:47:42,760
configurations in our network connection
9376
06:47:44,520 --> 06:47:45,520
Properties or adapter settings in
9377
06:47:46,978 --> 06:47:47,978
Windows so for instance you use a
9378
06:47:49,020 --> 06:47:50,020
specific protocol more than others and
9379
06:47:51,298 --> 06:47:52,298
you're confident in the stability of the
9380
06:47:52,860 --> 06:47:53,860
connection you can change the order of
9381
06:47:55,080 --> 06:47:56,080
binding
9382
06:47:56,160 --> 06:47:57,160
to potentially speed up your network
9383
06:47:58,260 --> 06:47:59,260
since what it basically does is it's
9384
06:48:00,420 --> 06:48:01,420
going to give a list
9385
06:48:03,478 --> 06:48:04,478
of each protocol that exists and it's
9386
06:48:05,760 --> 06:48:06,760
going to hit each protocol one after the
9387
06:48:07,620 --> 06:48:08,620
other so if there's one that you use
9388
06:48:08,820 --> 06:48:09,820
more you can set that at the top so it
9389
06:48:10,860 --> 06:48:11,860
doesn't have as far to go so as we can
9390
06:48:13,138 --> 06:48:14,138
see here we have several default
9391
06:48:15,058 --> 06:48:16,058
protocols
9392
06:48:16,378 --> 06:48:17,378
and they're going to be tested in order
9393
06:48:18,740 --> 06:48:19,740
for that available connection
9394
06:48:21,478 --> 06:48:22,478
and the first protocol that's found to
9395
06:48:23,400 --> 06:48:24,400
have a matching active protocol on the
9396
06:48:25,320 --> 06:48:26,320
receiving end is going to be the one we
9397
06:48:28,378 --> 06:48:29,378
use now that while this might sound like
9398
06:48:31,138 --> 06:48:32,138
a pretty decent method of doing things
9399
06:48:32,700 --> 06:48:33,700
it also opens your computer up to
9400
06:48:35,040 --> 06:48:36,040
utilizing a lesser protocol which is
9401
06:48:37,440 --> 06:48:38,440
potentially going to give you a slower
9402
06:48:38,760 --> 06:48:39,760
speed
9403
06:48:39,780 --> 06:48:40,780
so the graphical interface or properties
9404
06:48:42,298 --> 06:48:43,298
menu for your um network interface card
9405
06:48:45,780 --> 06:48:46,780
is where you're going to be able to
9406
06:48:47,040 --> 06:48:48,040
configure all of this stuff stuff such
9407
06:48:49,500 --> 06:48:50,500
as tcpip
9408
06:48:52,400 --> 06:48:53,400
DNS server assignment DHCP and so on and
9409
06:48:55,798 --> 06:48:56,798
so forth so after all of this it's
9410
06:48:58,378 --> 06:48:59,378
really important to understand that all
9411
06:48:59,820 --> 06:49:00,820
this organizing categorizing defining of
9412
06:49:02,340 --> 06:49:03,340
these protocols the assigning of rules
9413
06:49:04,020 --> 06:49:05,020
and roles all of this the the internet
9414
06:49:06,660 --> 06:49:07,660
didn't just happen overnight it's not
9415
06:49:09,240 --> 06:49:10,240
even necessarily the way we did it on
9416
06:49:10,978 --> 06:49:11,978
purpose these standards and these models
9417
06:49:13,378 --> 06:49:14,378
are going to continue to expand and
9418
06:49:16,080 --> 06:49:17,080
change and eventually might even have a
9419
06:49:19,200 --> 06:49:20,200
brand new model that we're going to have
9420
06:49:20,520 --> 06:49:21,520
to learn about
9421
06:49:21,600 --> 06:49:22,600
but in the meantime these models are
9422
06:49:23,700 --> 06:49:24,700
here to stay and they're going to remain
9423
06:49:25,558 --> 06:49:26,558
really important and especially uh in
9424
06:49:28,680 --> 06:49:29,680
the future you have to understand the
9425
06:49:30,240 --> 06:49:31,240
historical roots of the network so you
9426
06:49:32,218 --> 06:49:33,218
can be able to Define not only how to go
9427
06:49:34,558 --> 06:49:35,558
forward in the future but also how to
9428
06:49:37,020 --> 06:49:38,020
you know prepare yourself for a network
9429
06:49:38,400 --> 06:49:39,400
plus exam so let's just go back over
9430
06:49:40,680 --> 06:49:41,680
everything we've talked about one last
9431
06:49:42,120 --> 06:49:43,120
time we covered in great a lot of stuff
9432
06:49:44,700 --> 06:49:45,700
here right first we explain the purpose
9433
06:49:46,740 --> 06:49:47,740
of the TCP model and we compared the
9434
06:49:50,160 --> 06:49:51,160
tcpip model with the OSI model
9435
06:49:52,620 --> 06:49:53,620
remembering that the top three layers if
9436
06:49:55,138 --> 06:49:56,138
we look at this
9437
06:49:57,240 --> 06:49:58,240
if we do the three two one and then we
9438
06:50:00,600 --> 06:50:01,600
look at seven six five four
9439
06:50:05,280 --> 06:50:06,280
right two and one physical and data link
9440
06:50:07,740 --> 06:50:08,740
are going to go straight over here
9441
06:50:10,798 --> 06:50:11,798
to uh that physical layer one of the
9442
06:50:13,860 --> 06:50:14,860
tcpip model
9443
06:50:15,600 --> 06:50:16,600
then
9444
06:50:17,160 --> 06:50:18,160
the network layer is going to
9445
06:50:19,920 --> 06:50:20,920
correspond directly to the internet
9446
06:50:21,600 --> 06:50:22,600
layer the transport layers are going to
9447
06:50:24,120 --> 06:50:25,120
be the same
9448
06:50:27,058 --> 06:50:28,058
and
9449
06:50:28,558 --> 06:50:29,558
session presentation and application all
9450
06:50:31,680 --> 06:50:32,680
go over to the presentation layer in TCP
9451
06:50:36,000 --> 06:50:37,000
we also talked about defining data
9452
06:50:38,280 --> 06:50:39,280
encapsulation and we walk through how
9453
06:50:40,620 --> 06:50:41,620
fragmentation works on the internet
9454
06:50:42,660 --> 06:50:43,660
layer
9455
06:50:46,920 --> 06:50:47,920
and the reason we need to do that is
9456
06:50:48,600 --> 06:50:49,600
because of the maximum transmission unit
9457
06:50:52,080 --> 06:50:53,080
finally we talked about the fourth third
9458
06:50:54,600 --> 06:50:55,600
second and first layers of the tcpip
9459
06:50:57,540 --> 06:50:58,540
model and on each model we outlined some
9460
06:51:01,558 --> 06:51:02,558
of the important aspects of each layer
9461
06:51:03,958 --> 06:51:04,958
such as the
9462
06:51:06,540 --> 06:51:07,540
um
9463
06:51:07,520 --> 06:51:08,520
application layer
9464
06:51:09,478 --> 06:51:10,478
which again is the way that the
9465
06:51:11,820 --> 06:51:12,820
application is going to process all this
9466
06:51:14,160 --> 06:51:15,160
information the Tran sport layer
9467
06:51:18,600 --> 06:51:19,600
which is in charge of reliability
9468
06:51:22,920 --> 06:51:23,920
and it is where TCP which is connection
9469
06:51:26,100 --> 06:51:27,100
oriented or UDP which is connection less
9470
06:51:29,040 --> 06:51:30,040
live and this is also going to deal with
9471
06:51:31,860 --> 06:51:32,860
flow control
9472
06:51:35,340 --> 06:51:36,340
and also segmentation
9473
06:51:43,740 --> 06:51:44,740
we looked at uh Layer Two as well which
9474
06:51:47,760 --> 06:51:48,760
is the internet layer
9475
06:51:50,160 --> 06:51:51,160
and the fragmentation that happens there
9476
06:51:56,040 --> 06:51:57,040
and network one the network interface
9477
06:51:58,500 --> 06:51:59,500
layer
9478
06:52:04,378 --> 06:52:05,378
which is equivalent to all that physical
9479
06:52:06,298 --> 06:52:07,298
stuff that we've talked about we also
9480
06:52:08,580 --> 06:52:09,580
looked at how the terminology changes
9481
06:52:10,860 --> 06:52:11,860
remember on layer four we're talking
9482
06:52:13,440 --> 06:52:14,440
about data
9483
06:52:15,240 --> 06:52:16,240
on layer three
9484
06:52:17,760 --> 06:52:18,760
we're dealing with segments
9485
06:52:20,940 --> 06:52:21,940
on Layer Two
9486
06:52:25,680 --> 06:52:26,680
we're dealing with datagrams also called
9487
06:52:28,020 --> 06:52:29,020
packets and we broke down then on layer
9488
06:52:32,280 --> 06:52:33,280
one
9489
06:52:34,080 --> 06:52:35,080
frames and an Ethernet frame and all the
9490
06:52:36,958 --> 06:52:37,958
information that goes into that
9491
06:52:40,320 --> 06:52:41,320
finally we Define what an MTU black hole
9492
06:52:43,260 --> 06:52:44,260
was and we finished off everything by
9493
06:52:45,240 --> 06:52:46,240
talking about protocol binding which is
9494
06:52:47,760 --> 06:52:48,760
binding certain protocols to specific
9495
06:52:49,740 --> 06:52:50,740
Nicks and in a in a delineated order
9496
06:52:57,030 --> 06:52:58,030
[Music]
9497
06:53:17,218 --> 06:53:18,218
Network infrastructure and design
9498
06:53:19,760 --> 06:53:20,760
ethernet and implementing a wireless
9499
06:53:22,500 --> 06:53:23,500
network
9500
06:53:24,958 --> 06:53:25,958
so in the previous modules we were
9501
06:53:27,900 --> 06:53:28,900
introduced to many networking standards
9502
06:53:30,120 --> 06:53:31,120
models and Technologies now this module
9503
06:53:33,780 --> 06:53:34,780
is going into ethernet a little bit
9504
06:53:35,940 --> 06:53:36,940
further and specifically the
9505
06:53:37,680 --> 06:53:38,680
implementation of a wireless network so
9506
06:53:40,978 --> 06:53:41,978
the module objectives are first to
9507
06:53:43,200 --> 06:53:44,200
outline the different types of ethernet
9508
06:53:45,120 --> 06:53:46,120
networks that exist and then we're going
9509
06:53:47,520 --> 06:53:48,520
to go into the explanation of WLAN or
9510
06:53:50,638 --> 06:53:51,638
wireless LAN architecture
9511
06:53:53,878 --> 06:53:54,878
then we're going to Define and describe
9512
06:53:56,878 --> 06:53:57,878
the characteristics of an antenna and
9513
06:53:59,100 --> 06:54:00,100
have different types of antennas which
9514
06:54:00,840 --> 06:54:01,840
is actually pretty important for the
9515
06:54:02,638 --> 06:54:03,638
network plus exam specifically
9516
06:54:05,340 --> 06:54:06,340
wireless antenna performance factors and
9517
06:54:09,000 --> 06:54:10,000
then by the end of the module we're
9518
06:54:10,200 --> 06:54:11,200
going to have a complete understanding
9519
06:54:11,878 --> 06:54:12,878
of the 802.11 standard and its
9520
06:54:15,000 --> 06:54:16,000
Associated modes we're going to talk
9521
06:54:18,180 --> 06:54:19,180
about uh the beacon frame and we're also
9522
06:54:21,958 --> 06:54:22,958
going to talk about what determines
9523
06:54:25,260 --> 06:54:26,260
where you place your wireless access
9524
06:54:27,780 --> 06:54:28,780
point or your WAP
9525
06:54:31,680 --> 06:54:32,680
and we'll finish by talking about how to
9526
06:54:34,320 --> 06:54:35,320
properly Implement a wireless network
9527
06:54:37,920 --> 06:54:38,920
so an Ethernet network is perhaps one of
9528
06:54:40,620 --> 06:54:41,620
the easiest networks to plan and
9529
06:54:42,420 --> 06:54:43,420
implement depending on the size of your
9530
06:54:44,340 --> 06:54:45,340
network and the equipment being used
9531
06:54:45,718 --> 06:54:46,718
there are a bunch of different kinds of
9532
06:54:47,760 --> 06:54:48,760
small ethernet Network implementations
9533
06:54:49,798 --> 06:54:50,798
that you can use some of the typical
9534
06:54:51,958 --> 06:54:52,958
equipment that you're going to find in
9535
06:54:53,520 --> 06:54:54,520
an Ethernet Network might be a hub
9536
06:54:56,340 --> 06:54:57,340
an ethernet cable which can either be
9537
06:54:58,798 --> 06:54:59,798
what we call straight through
9538
06:55:03,120 --> 06:55:04,120
or crossover
9539
06:55:05,458 --> 06:55:06,458
and we've looked at that a little bit
9540
06:55:07,020 --> 06:55:08,020
more in depth previously
9541
06:55:08,820 --> 06:55:09,820
and a switch
9542
06:55:10,680 --> 06:55:11,680
or and a router so a network can also
9543
06:55:14,638 --> 06:55:15,638
contain a combination of these or all of
9544
06:55:17,520 --> 06:55:18,520
them generally so much we're not going
9545
06:55:19,978 --> 06:55:20,978
to see hubs a lot anymore but they're
9546
06:55:22,798 --> 06:55:23,798
still mentioned on the exam
9547
06:55:24,540 --> 06:55:25,540
so a very simple ethernet Network that
9548
06:55:27,298 --> 06:55:28,298
involves a hub is called a Hub Network
9549
06:55:29,940 --> 06:55:30,940
Now to create this network all you need
9550
06:55:32,160 --> 06:55:33,160
is two devices
9551
06:55:34,500 --> 06:55:35,500
a hub
9552
06:55:35,820 --> 06:55:36,820
and an ethernet cable
9553
06:55:38,160 --> 06:55:39,160
this type of network is not capable of
9554
06:55:40,500 --> 06:55:41,500
reaching the internet and it's typically
9555
06:55:42,660 --> 06:55:43,660
only going to be used for file sharing
9556
06:55:44,760 --> 06:55:45,760
or printing and you're not going to want
9557
06:55:46,920 --> 06:55:47,920
to have a lot of devices either because
9558
06:55:48,600 --> 06:55:49,600
it's quickly going to become very slow
9559
06:55:51,120 --> 06:55:52,120
due to the fact that hubs as you
9560
06:55:53,040 --> 06:55:54,040
remember operate on layer one of the OSI
9561
06:55:56,580 --> 06:55:57,580
model and therefore broadcast every
9562
06:56:00,660 --> 06:56:01,660
um uh input data out to everything else
9563
06:56:05,040 --> 06:56:06,040
now the next type is also very easy to
9564
06:56:07,320 --> 06:56:08,320
implement this is considered a crossover
9565
06:56:09,540 --> 06:56:10,540
Network or a peer
9566
06:56:13,378 --> 06:56:14,378
to peer Network and the reason is
9567
06:56:15,840 --> 06:56:16,840
because there is no device sitting in
9568
06:56:19,320 --> 06:56:20,320
the center
9569
06:56:20,340 --> 06:56:21,340
a crossover Network only needs the two
9570
06:56:22,440 --> 06:56:23,440
devices in the crossover cable to
9571
06:56:24,600 --> 06:56:25,600
connect them and the reason we must use
9572
06:56:25,920 --> 06:56:26,920
a crossover cable is because we're
9573
06:56:27,420 --> 06:56:28,420
switching if you recall the one two
9574
06:56:30,000 --> 06:56:31,000
three six pins we're switching these
9575
06:56:32,400 --> 06:56:33,400
pins so that way on one side the data is
9576
06:56:35,400 --> 06:56:36,400
sent on the other side it's received
9577
06:56:39,780 --> 06:56:40,780
of course newer devices might not always
9578
06:56:42,360 --> 06:56:43,360
need this crossover cable anymore
9579
06:56:44,280 --> 06:56:45,280
because a lot of modern Nicks have Auto
9580
06:56:47,638 --> 06:56:48,638
switching capabilities which will
9581
06:56:49,320 --> 06:56:50,320
automatically determine and switch these
9582
06:56:51,000 --> 06:56:52,000
pins for you now another ethernet
9583
06:56:53,760 --> 06:56:54,760
network is one that uses a router to
9584
06:56:56,820 --> 06:56:57,820
connect devices to the outside world or
9585
06:56:59,340 --> 06:57:00,340
to the internet
9586
06:57:01,080 --> 06:57:02,080
and a switch can often be placed in
9587
06:57:04,558 --> 06:57:05,558
between the router which leads out to
9588
06:57:06,780 --> 06:57:07,780
the Wan
9589
06:57:08,458 --> 06:57:09,458
in the internal Network or the LAN in
9590
06:57:12,058 --> 06:57:13,058
order to alleviate Network congestion
9591
06:57:14,218 --> 06:57:15,218
and to allow for more devices to be
9592
06:57:16,440 --> 06:57:17,440
added
9593
06:57:17,400 --> 06:57:18,400
now just so we remember a switch
9594
06:57:19,378 --> 06:57:20,378
operates on Layer Two although there are
9595
06:57:22,740 --> 06:57:23,740
switches that do routing and those are
9596
06:57:24,420 --> 06:57:25,420
called layer 3 switches and then the
9597
06:57:27,660 --> 06:57:28,660
router as we just mentioned operates on
9598
06:57:30,000 --> 06:57:31,000
layer three of the OSI model
9599
06:57:33,180 --> 06:57:34,180
now another point about ethernet
9600
06:57:35,160 --> 06:57:36,160
networks that is important is that
9601
06:57:36,718 --> 06:57:37,718
ethernet uses destination and Source
9602
06:57:39,718 --> 06:57:40,718
access points to assist in keeping tabs
9603
06:57:42,840 --> 06:57:43,840
on all the multiple channels that are
9604
06:57:44,878 --> 06:57:45,878
used in network communications these are
9605
06:57:47,878 --> 06:57:48,878
called sap or service access points and
9606
06:57:52,260 --> 06:57:53,260
in the previous modules we discussed how
9607
06:57:54,000 --> 06:57:55,000
data flows through these layers in the
9608
06:57:56,160 --> 06:57:57,160
network models well here these access
9609
06:57:58,978 --> 06:57:59,978
points are used to map the network layer
9610
06:58:02,040 --> 06:58:03,040
communication or IP through the physical
9611
06:58:05,400 --> 06:58:06,400
layer or layer 1. now the access points
9612
06:58:08,760 --> 06:58:09,760
allow a single physical connection to be
9613
06:58:11,580 --> 06:58:12,580
utilized for many logical connections
9614
06:58:14,218 --> 06:58:15,218
for tcpip this would be like a Nick
9615
06:58:17,160 --> 06:58:18,160
because these access points are going to
9616
06:58:19,200 --> 06:58:20,200
be on the local side only they're
9617
06:58:21,780 --> 06:58:22,780
selected by the server managing those
9618
06:58:24,900 --> 06:58:25,900
services
9619
06:58:26,100 --> 06:58:27,100
now to keep what TCP as an example when
9620
06:58:28,860 --> 06:58:29,860
a user is accessing a website for
9621
06:58:30,600 --> 06:58:31,600
example
9622
06:58:31,378 --> 06:58:32,378
a connection is made with the web server
9623
06:58:33,540 --> 06:58:34,540
and the computer downloads that website
9624
06:58:36,180 --> 06:58:37,180
along with the website are references to
9625
06:58:38,700 --> 06:58:39,700
parts of the page such as files that are
9626
06:58:40,680 --> 06:58:41,680
associated with the web page sound image
9627
06:58:44,340 --> 06:58:45,340
other things like JavaScript and these
9628
06:58:47,400 --> 06:58:48,400
files are stored on the web server and
9629
06:58:49,740 --> 06:58:50,740
when the user interacts with the website
9630
06:58:51,360 --> 06:58:52,360
the access point ensures that the
9631
06:58:53,638 --> 06:58:54,638
computer can differentiate between the
9632
06:58:56,100 --> 06:58:57,100
ethernet frames for the images and those
9633
06:58:58,798 --> 06:58:59,798
for sound files and those for other
9634
06:59:00,660 --> 06:59:01,660
types
9635
06:59:01,620 --> 06:59:02,620
okay so in a lot of the previous lessons
9636
06:59:04,080 --> 06:59:05,080
we've been talking about the methods of
9637
06:59:05,878 --> 06:59:06,878
connecting our devices mostly through
9638
06:59:07,620 --> 06:59:08,620
physical means and we defined that many
9639
06:59:10,378 --> 06:59:11,378
Technologies are commonly used in both
9640
06:59:12,958 --> 06:59:13,958
wired and wireless networks otherwise
9641
06:59:16,200 --> 06:59:17,200
known as bounded and unbounded networks
9642
06:59:18,660 --> 06:59:19,660
so here we're going to discuss
9643
06:59:19,920 --> 06:59:20,920
specifically WLAN or Wireless local area
9644
06:59:22,680 --> 06:59:23,680
networks in Greater detail starting with
9645
06:59:26,160 --> 06:59:27,160
the architecture
9646
06:59:28,378 --> 06:59:29,378
there are several components that we
9647
06:59:30,660 --> 06:59:31,660
really need to Define
9648
06:59:32,700 --> 06:59:33,700
the first component is what's called an
9649
06:59:34,920 --> 06:59:35,920
sta or the station
9650
06:59:37,978 --> 06:59:38,978
the wireless sta is any device that has
9651
06:59:40,978 --> 06:59:41,978
a network adapter card or Nick that
9652
06:59:44,218 --> 06:59:45,218
conforms to the 802.11 standard
9653
06:59:48,240 --> 06:59:49,240
and you remember the specific standard
9654
06:59:50,100 --> 06:59:51,100
for wireless is 802.11 as opposed to
9655
06:59:52,798 --> 06:59:53,798
8023 which is ethernet now the next
9656
06:59:55,558 --> 06:59:56,558
device is called an AP or an access
9657
06:59:58,020 --> 06:59:59,020
point look familiar now this is very
9658
07:00:00,780 --> 07:00:01,780
different from the service access point
9659
07:00:02,760 --> 07:00:03,760
I just talked about because an AP in
9660
07:00:05,160 --> 07:00:06,160
this sense it is a device or a software
9661
07:00:08,280 --> 07:00:09,280
implementation that allows wireless
9662
07:00:10,378 --> 07:00:11,378
devices to communicate with each other
9663
07:00:12,298 --> 07:00:13,298
and to connect to a wired Network an
9664
07:00:15,240 --> 07:00:16,240
access pointer AP also sometimes called
9665
07:00:18,478 --> 07:00:19,478
wireless access point offers wireless
9666
07:00:21,420 --> 07:00:22,420
devices some higher levels of security
9667
07:00:23,940 --> 07:00:24,940
as well and can act as the bridging
9668
07:00:27,240 --> 07:00:28,240
component
9669
07:00:28,378 --> 07:00:29,378
between the STA
9670
07:00:30,900 --> 07:00:31,900
and the backbone of the network for
9671
07:00:33,360 --> 07:00:34,360
access
9672
07:00:34,798 --> 07:00:35,798
so the next component that we need to
9673
07:00:37,740 --> 07:00:38,740
identify is the WDS or the wireless
9674
07:00:41,940 --> 07:00:42,940
distribution system this device is the
9675
07:00:45,360 --> 07:00:46,360
authority in terms of Access Control to
9676
07:00:48,420 --> 07:00:49,420
resources and ensures that devices are
9677
07:00:50,940 --> 07:00:51,940
mobile this allows multiple access
9678
07:00:53,520 --> 07:00:54,520
points
9679
07:00:55,020 --> 07:00:56,020
to be interconnected wirelessly which
9680
07:00:58,620 --> 07:00:59,620
allows you which allows the aps to be
9681
07:01:01,200 --> 07:01:02,200
connected and extend the wireless range
9682
07:01:03,478 --> 07:01:04,478
of the network without having to connect
9683
07:01:05,280 --> 07:01:06,280
the wire at the access points directly
9684
07:01:07,680 --> 07:01:08,680
to the backbone and again the backbone
9685
07:01:10,138 --> 07:01:11,138
would be the internet
9686
07:01:13,138 --> 07:01:14,138
or the rest of the network if we're
9687
07:01:15,120 --> 07:01:16,120
talking about a lan now the system has
9688
07:01:17,400 --> 07:01:18,400
three types of AP stations we have
9689
07:01:20,940 --> 07:01:21,940
something called a remote base station
9690
07:01:22,620 --> 07:01:23,620
which is the access point that connects
9691
07:01:25,320 --> 07:01:26,320
directly to the wireless clients or
9692
07:01:27,180 --> 07:01:28,180
devices a relay based station just
9693
07:01:30,478 --> 07:01:31,478
relays or repeats the information
9694
07:01:32,100 --> 07:01:33,100
between other stations or devices and a
9695
07:01:35,340 --> 07:01:36,340
main base station
9696
07:01:36,840 --> 07:01:37,840
now the last thing I want to talk about
9697
07:01:39,120 --> 07:01:40,120
is the main base station which is
9698
07:01:42,000 --> 07:01:43,000
connected to the wired or Ethernet or
9699
07:01:44,940 --> 07:01:45,940
backbone Network
9700
07:01:47,160 --> 07:01:48,160
using these components there are a
9701
07:01:49,320 --> 07:01:50,320
number of different ways we can actually
9702
07:01:50,700 --> 07:01:51,700
configure a wireless LAN the service set
9703
07:01:54,478 --> 07:01:55,478
is what defines how your network is
9704
07:01:56,940 --> 07:01:57,940
configured now there are three standard
9705
07:01:59,340 --> 07:02:00,340
ways that W lands or Wireless Lans can
9706
07:02:02,760 --> 07:02:03,760
be configured
9707
07:02:04,680 --> 07:02:05,680
first configuration is what's called a
9708
07:02:06,900 --> 07:02:07,900
BSS or a basic service set the BSS in
9709
07:02:12,000 --> 07:02:13,000
its simplest sense is comprised of an AP
9710
07:02:14,878 --> 07:02:15,878
an access point and an sta a station
9711
07:02:18,020 --> 07:02:19,020
although many stations with a single AP
9712
07:02:20,900 --> 07:02:21,900
is also considered a BSS so I only need
9713
07:02:26,040 --> 07:02:27,040
one station but I can have multiple the
9714
07:02:28,378 --> 07:02:29,378
trick here is that I have only one AP
9715
07:02:31,978 --> 07:02:32,978
now client nodes like these may not be
9716
07:02:36,240 --> 07:02:37,240
necessarily explicitly aware of each
9717
07:02:38,878 --> 07:02:39,878
other using a BSS we are easily
9718
07:02:45,540 --> 07:02:46,540
able to extend our network coverage area
9719
07:02:48,180 --> 07:02:49,180
and the distance between our wireless
9720
07:02:50,218 --> 07:02:51,218
devices by forwarding
9721
07:02:52,920 --> 07:02:53,920
packets
9722
07:02:54,360 --> 07:02:55,360
through a wireless access point
9723
07:02:56,878 --> 07:02:57,878
so that we can gain access to the wired
9724
07:02:58,740 --> 07:02:59,740
Network
9725
07:03:00,600 --> 07:03:01,600
now wlans can also be configured in
9726
07:03:03,240 --> 07:03:04,240
what's called an ESS or an extended
9727
07:03:05,400 --> 07:03:06,400
service set an ESS is comprised of two
9728
07:03:08,878 --> 07:03:09,878
or more bss's basic service sets and the
9729
07:03:12,780 --> 07:03:13,780
purpose of an ESS is to allow mobile
9730
07:03:14,700 --> 07:03:15,700
devices to maintain a constant
9731
07:03:17,100 --> 07:03:18,100
connection
9732
07:03:18,600 --> 07:03:19,600
it's the network while you're roaming so
9733
07:03:21,000 --> 07:03:22,000
each BSS in an ESS or an extended
9734
07:03:24,058 --> 07:03:25,058
service set is going to have the same
9735
07:03:26,700 --> 07:03:27,700
service set identifier otherwise known
9736
07:03:29,520 --> 07:03:30,520
as an SSID
9737
07:03:32,100 --> 07:03:33,100
this makes multiple bsses appear as if
9738
07:03:36,298 --> 07:03:37,298
they're only one
9739
07:03:37,860 --> 07:03:38,860
so as an example if you think about when
9740
07:03:40,440 --> 07:03:41,440
you walk through an airport pretty much
9741
07:03:42,780 --> 07:03:43,780
wherever you sit we have a decently
9742
07:03:45,478 --> 07:03:46,478
strong Wireless signal theoretically of
9743
07:03:48,180 --> 07:03:49,180
course so thinking about what's that
9744
07:03:50,580 --> 07:03:51,580
signal they wouldn't be easy for a
9745
07:03:52,440 --> 07:03:53,440
single access point to provide you a
9746
07:03:54,718 --> 07:03:55,718
signal that's that strong for that much
9747
07:03:56,638 --> 07:03:57,638
space in fact it's pretty much
9748
07:03:58,680 --> 07:03:59,680
impossible so instead there are many
9749
07:04:01,320 --> 07:04:02,320
access points APS arrange strategically
9750
07:04:04,320 --> 07:04:05,320
to allow full coverage throughout the
9751
07:04:06,900 --> 07:04:07,900
airport and combined they make up this
9752
07:04:09,780 --> 07:04:10,780
ESS or extended service set that's why
9753
07:04:12,478 --> 07:04:13,478
we see the same network name no matter
9754
07:04:14,100 --> 07:04:15,100
where you are within that Network range
9755
07:04:16,260 --> 07:04:17,260
now the BSS can either operate on the
9756
07:04:19,798 --> 07:04:20,798
same channel or on separate channels
9757
07:04:22,558 --> 07:04:23,558
which effectively increases the
9758
07:04:24,958 --> 07:04:25,958
throughput by having separate channels
9759
07:04:26,760 --> 07:04:27,760
that they're not going to overlap on
9760
07:04:28,620 --> 07:04:29,620
finally we have What's called the ibss
9761
07:04:32,040 --> 07:04:33,040
this is an independent basic service set
9762
07:04:35,218 --> 07:04:36,218
and ibss is created when there is a
9763
07:04:37,740 --> 07:04:38,740
isn't a controlling access point but
9764
07:04:40,320 --> 07:04:41,320
instead there's what we call an ad hoc
9765
07:04:42,840 --> 07:04:43,840
network and as the name implies
9766
07:04:46,138 --> 07:04:47,138
this means that uh this is a makeshift
9767
07:04:49,620 --> 07:04:50,620
or an improvised in technical terms uh
9768
07:04:52,680 --> 07:04:53,680
wireless network that combines Network
9769
07:04:55,320 --> 07:04:56,320
elements to make a network with minimal
9770
07:04:57,540 --> 07:04:58,540
planning where all the devices on the
9771
07:04:59,760 --> 07:05:00,760
network are essentially equal in status
9772
07:05:02,700 --> 07:05:03,700
and are free to talk with any other ad
9773
07:05:06,600 --> 07:05:07,600
hoc devices that are in range this ad
9774
07:05:09,058 --> 07:05:10,058
hoc configuration which is also called
9775
07:05:10,920 --> 07:05:11,920
by the way a peer-to-peer configuration
9776
07:05:15,718 --> 07:05:16,718
is where stas are performing their own
9777
07:05:19,020 --> 07:05:20,020
AP functions as well as their own client
9778
07:05:22,320 --> 07:05:23,320
operations independent of any sort of
9779
07:05:24,900 --> 07:05:25,900
central device
9780
07:05:26,400 --> 07:05:27,400
so if you've ever connected two
9781
07:05:28,860 --> 07:05:29,860
computers directly together in order to
9782
07:05:30,718 --> 07:05:31,718
say
9783
07:05:31,680 --> 07:05:32,680
transfer files or perhaps you've
9784
07:05:33,840 --> 07:05:34,840
connected your smartphone directly to
9785
07:05:36,660 --> 07:05:37,660
your computer in order to transfer files
9786
07:05:38,580 --> 07:05:39,580
without the use of an access point
9787
07:05:40,260 --> 07:05:41,260
you're using what's called an ibss or an
9788
07:05:43,320 --> 07:05:44,320
ad hoc wireless network many aspects of
9789
07:05:46,920 --> 07:05:47,920
antennas and their characteristics that
9790
07:05:49,260 --> 07:05:50,260
are a little outside of the scope the
9791
07:05:50,820 --> 07:05:51,820
network plus exam but there are still a
9792
07:05:52,860 --> 07:05:53,860
few Basics that are important
9793
07:05:54,840 --> 07:05:55,840
the first of which is to Define what an
9794
07:05:57,540 --> 07:05:58,540
antenna actually is and how it functions
9795
07:06:00,058 --> 07:06:01,058
on a fundamental level
9796
07:06:01,860 --> 07:06:02,860
so an antenna is a physical device that
9797
07:06:04,680 --> 07:06:05,680
are transmits or receives
9798
07:06:06,860 --> 07:06:07,860
electromagnetic waves and then converts
9799
07:06:08,940 --> 07:06:09,940
those waves to and from high frequency
9800
07:06:12,000 --> 07:06:13,000
signal now the antenna's physical
9801
07:06:14,298 --> 07:06:15,298
characteristics and dimensions are going
9802
07:06:16,558 --> 07:06:17,558
to dictate these frequencies that it can
9803
07:06:18,660 --> 07:06:19,660
transmit or receive and depending on the
9804
07:06:21,660 --> 07:06:22,660
purpose of the antenna
9805
07:06:23,340 --> 07:06:24,340
there are different types that can be
9806
07:06:25,500 --> 07:06:26,500
used for instance the radiation pattern
9807
07:06:28,138 --> 07:06:29,138
is different on some antennas versus
9808
07:06:30,120 --> 07:06:31,120
others
9809
07:06:31,260 --> 07:06:32,260
now another term we really need to
9810
07:06:32,760 --> 07:06:33,760
understand is the term gain which
9811
07:06:34,680 --> 07:06:35,680
describes the intensity of an antenna in
9812
07:06:37,500 --> 07:06:38,500
a specific Direction related to the
9813
07:06:40,458 --> 07:06:41,458
hypothetical intensity of a given
9814
07:06:43,500 --> 07:06:44,500
standard which is the ideal in other
9815
07:06:46,020 --> 07:06:47,020
words we always have a hypothetical
9816
07:06:51,718 --> 07:06:52,718
versus
9817
07:06:55,138 --> 07:06:56,138
the reality
9818
07:06:57,540 --> 07:06:58,540
now this is achieved by focusing on
9819
07:06:59,340 --> 07:07:00,340
What's called the RF or the radio
9820
07:07:01,138 --> 07:07:02,138
frequency
9821
07:07:02,700 --> 07:07:03,700
in a more manageable or concentrated
9822
07:07:05,100 --> 07:07:06,100
plane this is what we see as strength on
9823
07:07:08,218 --> 07:07:09,218
your computer right if you've seen this
9824
07:07:10,500 --> 07:07:11,500
thing and you have different
9825
07:07:12,900 --> 07:07:13,900
number of bars that's what we're really
9826
07:07:15,120 --> 07:07:16,120
talking about here is the gain
9827
07:07:17,280 --> 07:07:18,280
in most cases we want more gain which is
9828
07:07:19,798 --> 07:07:20,798
better but there are certain legal
9829
07:07:21,780 --> 07:07:22,780
limits and adding power can potentially
9830
07:07:23,820 --> 07:07:24,820
have some negative ramifications so gain
9831
07:07:26,760 --> 07:07:27,760
can also come from an external Source
9832
07:07:28,978 --> 07:07:29,978
like an amplifier which means that it
9833
07:07:32,760 --> 07:07:33,760
amplifies the signal making it stronger
9834
07:07:35,520 --> 07:07:36,520
and it's measured in decibels
9835
07:07:39,058 --> 07:07:40,058
now while this explanation is very
9836
07:07:41,280 --> 07:07:42,280
simplified the antenna gain is how it's
9837
07:07:43,860 --> 07:07:44,860
affected by things such as the size and
9838
07:07:46,378 --> 07:07:47,378
shape of the antenna and the amount of
9839
07:07:48,360 --> 07:07:49,360
electrical power that's applied to the
9840
07:07:50,218 --> 07:07:51,218
signal and it's all kind of complicated
9841
07:07:52,500 --> 07:07:53,500
which is why there are people who
9842
07:07:54,180 --> 07:07:55,180
specifically are RF or radio frequency
9843
07:07:56,280 --> 07:07:57,280
engineers
9844
07:07:57,600 --> 07:07:58,600
so what you really need to remember
9845
07:07:59,040 --> 07:08:00,040
about all this is first
9846
07:08:01,440 --> 07:08:02,440
the physical characteristics of an
9847
07:08:04,080 --> 07:08:05,080
antenna affect its gain
9848
07:08:06,478 --> 07:08:07,478
second a higher gain is usually good but
9849
07:08:09,600 --> 07:08:10,600
potentially dangerous
9850
07:08:11,100 --> 07:08:12,100
third more gain can be achieved by using
9851
07:08:14,340 --> 07:08:15,340
an amplifier and fourth we're going to
9852
07:08:17,218 --> 07:08:18,218
measure it in decibels
9853
07:08:19,740 --> 07:08:20,740
so now that we've defined some of this
9854
07:08:21,478 --> 07:08:22,478
terminology when it comes to antennas
9855
07:08:23,218 --> 07:08:24,218
let's take a look at some of the
9856
07:08:24,360 --> 07:08:25,360
wireless antenna types
9857
07:08:26,638 --> 07:08:27,638
now Wireless antennas can be fairly
9858
07:08:28,978 --> 07:08:29,978
organized into two general broad
9859
07:08:31,378 --> 07:08:32,378
categories the first category is
9860
07:08:34,020 --> 07:08:35,020
directional directional antennas attempt
9861
07:08:37,320 --> 07:08:38,320
to focus the radio waves into a narrow
9862
07:08:39,420 --> 07:08:40,420
beam going in one specific Direction
9863
07:08:41,298 --> 07:08:42,298
because the signal is being focused it
9864
07:08:44,458 --> 07:08:45,458
typically means that these antennas are
9865
07:08:45,900 --> 07:08:46,900
going to have a higher gain
9866
07:08:47,940 --> 07:08:48,940
and for the same reason a relatively
9867
07:08:50,240 --> 07:08:51,240
narrower transmission beam versus other
9868
07:08:52,978 --> 07:08:53,978
types as you can see
9869
07:08:54,718 --> 07:08:55,718
these characteristics allow for a couple
9870
07:08:56,520 --> 07:08:57,520
of Bennetts benefits such as a focus
9871
07:08:58,860 --> 07:08:59,860
beam which ensures a better signal
9872
07:09:01,020 --> 07:09:02,020
quality and a smaller transmission beam
9873
07:09:03,718 --> 07:09:04,718
which means that there's less area of
9874
07:09:05,700 --> 07:09:06,700
interference
9875
07:09:07,200 --> 07:09:08,200
how directional antennas are really
9876
07:09:09,120 --> 07:09:10,120
commonplace in implementations of
9877
07:09:11,638 --> 07:09:12,638
point-to-point networks which makes
9878
07:09:13,680 --> 07:09:14,680
sense because I have this Limited sort
9879
07:09:16,558 --> 07:09:17,558
of area in which the waves are going to
9880
07:09:19,020 --> 07:09:20,020
be traveling and perhaps most commonly
9881
07:09:21,600 --> 07:09:22,600
you've seen them in Dish Networks for
9882
07:09:24,660 --> 07:09:25,660
satellite TV and the internet
9883
07:09:26,878 --> 07:09:27,878
now the next category of antenna is are
9884
07:09:30,298 --> 07:09:31,298
called omnidirectional antennas this
9885
07:09:33,000 --> 07:09:34,000
type of antenna emits the radio waves in
9886
07:09:35,160 --> 07:09:36,160
all directions on the same plane equally
9887
07:09:38,280 --> 07:09:39,280
in some ways these are called donuts
9888
07:09:41,040 --> 07:09:42,040
because
9889
07:09:42,240 --> 07:09:43,240
the wave comes out in a donut looking
9890
07:09:44,638 --> 07:09:45,638
shape now because the signal is being
9891
07:09:47,280 --> 07:09:48,280
transmitted in any direction such as on
9892
07:09:51,360 --> 07:09:52,360
a wireless router
9893
07:09:53,520 --> 07:09:54,520
these antennas have a relatively low
9894
07:09:56,760 --> 07:09:57,760
gain when compared
9895
07:10:00,020 --> 07:10:01,020
with a uh directional antenna now where
9896
07:10:04,378 --> 07:10:05,378
these antennas lack and gain they make
9897
07:10:06,120 --> 07:10:07,120
up for it because obviously they have a
9898
07:10:08,638 --> 07:10:09,638
greater coverage area
9899
07:10:14,820 --> 07:10:15,820
as the donut wave implies
9900
07:10:17,580 --> 07:10:18,580
the good part about this greater
9901
07:10:18,958 --> 07:10:19,958
coverage area is that transmitting and
9902
07:10:21,298 --> 07:10:22,298
receiving Stations don't have to have a
9903
07:10:24,000 --> 07:10:25,000
specific alignment with one another
9904
07:10:26,638 --> 07:10:27,638
they can be in any direction from the
9905
07:10:28,500 --> 07:10:29,500
antenna these antennas are really going
9906
07:10:30,840 --> 07:10:31,840
to be used in distributed networks and
9907
07:10:33,120 --> 07:10:34,120
multi-point networks as well so
9908
07:10:35,100 --> 07:10:36,100
omnidirectional antennas are implemented
9909
07:10:37,200 --> 07:10:38,200
everywhere from cell phones to radio
9910
07:10:40,020 --> 07:10:41,020
broadcasting antennas to walkie-talkies
9911
07:10:42,660 --> 07:10:43,660
to GPS to mostly our wireless networks
9912
07:10:47,760 --> 07:10:48,760
at home and in a lot of offices Etc
9913
07:10:51,600 --> 07:10:52,600
so now that we've talked about a lot of
9914
07:10:53,820 --> 07:10:54,820
the different types of antennas and
9915
07:10:55,500 --> 07:10:56,500
their characteristics the the last thing
9916
07:10:57,900 --> 07:10:58,900
I'd like to mention about gain is the
9917
07:11:00,000 --> 07:11:01,000
more gain the antenna has the smaller
9918
07:11:02,820 --> 07:11:03,820
the effective angle of use needs to be
9919
07:11:05,638 --> 07:11:06,638
so the next thing we need to do is
9920
07:11:07,680 --> 07:11:08,680
outline what's going to affect the
9921
07:11:10,440 --> 07:11:11,440
performance of these antennas
9922
07:11:12,900 --> 07:11:13,900
so the physical layer of the network the
9923
07:11:15,120 --> 07:11:16,120
transmission of bits from one point to
9924
07:11:16,920 --> 07:11:17,920
the other there are a lot of things that
9925
07:11:18,780 --> 07:11:19,780
can hinder the data while it's in
9926
07:11:20,580 --> 07:11:21,580
transit these things that are going to
9927
07:11:23,280 --> 07:11:24,280
impede our signal are going to depend on
9928
07:11:25,500 --> 07:11:26,500
the type of data in transmission
9929
07:11:28,378 --> 07:11:29,378
so for infrared data Transmissions the
9930
07:11:32,340 --> 07:11:33,340
antennas need a line of sight or Los
9931
07:11:34,558 --> 07:11:35,558
just like your remote control almost
9932
07:11:37,260 --> 07:11:38,260
anything that obstructs this loss is
9933
07:11:39,478 --> 07:11:40,478
going to affect the signal this could
9934
07:11:41,458 --> 07:11:42,458
include stuff like smoke smog fog dust
9935
07:11:45,440 --> 07:11:46,440
even pulses of light and bright sunlight
9936
07:11:48,780 --> 07:11:49,780
can very easily change the maximum
9937
07:11:51,180 --> 07:11:52,180
transmitting distance and obviously if
9938
07:11:53,520 --> 07:11:54,520
anything
9939
07:11:55,080 --> 07:11:56,080
standing in the way we're going to be in
9940
07:11:57,180 --> 07:11:58,180
big trouble
9941
07:11:58,260 --> 07:11:59,260
now for microwave Transmissions the
9942
07:12:01,320 --> 07:12:02,320
signals also considered Los or line of
9943
07:12:04,500 --> 07:12:05,500
sight this typically doesn't mean that
9944
07:12:06,600 --> 07:12:07,600
we need to be able to see the receiving
9945
07:12:08,280 --> 07:12:09,280
station with our naked eye it just means
9946
07:12:10,558 --> 07:12:11,558
that the signal has to have an unimpeded
9947
07:12:12,660 --> 07:12:13,660
path from the source of the destination
9948
07:12:14,400 --> 07:12:15,400
most commonly satellite the ground
9949
07:12:17,700 --> 07:12:18,700
station has to be within the footprint
9950
07:12:20,100 --> 07:12:21,100
of the orbiting satellite generally
9951
07:12:23,040 --> 07:12:24,040
speaking
9952
07:12:24,240 --> 07:12:25,240
distance is the performance Factor
9953
07:12:26,280 --> 07:12:27,280
that's going to affect these microwave
9954
07:12:28,138 --> 07:12:29,138
Transmissions the most
9955
07:12:29,940 --> 07:12:30,940
now the factors that are going to affect
9956
07:12:32,160 --> 07:12:33,160
radio Transmissions which are the ones
9957
07:12:34,500 --> 07:12:35,500
we use in Wi-Fi settings mostly start
9958
07:12:37,378 --> 07:12:38,378
with the antenna itself
9959
07:12:39,058 --> 07:12:40,058
so the signal characteristics of an
9960
07:12:41,040 --> 07:12:42,040
antenna can affect the maximum
9961
07:12:42,718 --> 07:12:43,718
transmitting distance also performance
9962
07:12:45,298 --> 07:12:46,298
can be limited if there are any objects
9963
07:12:47,160 --> 07:12:48,160
that are very electrical or give off a
9964
07:12:50,160 --> 07:12:51,160
lot of magnet magnetic fields near or
9965
07:12:53,458 --> 07:12:54,458
around the transmitting or receiving
9966
07:12:55,138 --> 07:12:56,138
stations and this is going to cause
9967
07:12:56,820 --> 07:12:57,820
problems to arise
9968
07:12:58,378 --> 07:12:59,378
we can also have normal ambient noise or
9969
07:13:01,080 --> 07:13:02,080
environmental conditions which can
9970
07:13:02,760 --> 07:13:03,760
affect the distance these signals can
9971
07:13:04,680 --> 07:13:05,680
travel finally the greatest factor
9972
07:13:07,200 --> 07:13:08,200
that's going to affect Bluetooth
9973
07:13:08,638 --> 07:13:09,638
Transmissions is the distance between
9974
07:13:10,978 --> 07:13:11,978
the uh the devices just because of the
9975
07:13:14,760 --> 07:13:15,760
technology we're using as most Bluetooth
9976
07:13:17,218 --> 07:13:18,218
devices are what we call Class 2 devices
9977
07:13:21,660 --> 07:13:22,660
this means that we have about a 10 meter
9978
07:13:24,840 --> 07:13:25,840
which is equivalent to around although a
9979
07:13:27,840 --> 07:13:28,840
little more than 30 feet
9980
07:13:29,820 --> 07:13:30,820
and this is due to power limitations now
9981
07:13:33,660 --> 07:13:34,660
depending on the type of Bluetooth
9982
07:13:34,798 --> 07:13:35,798
device it may operate on the 2.4
9983
07:13:37,200 --> 07:13:38,200
gigahertz
9984
07:13:39,298 --> 07:13:40,298
frequency which by the way is the same
9985
07:13:41,340 --> 07:13:42,340
as Wi-Fi and so there that's why we're
9986
07:13:43,558 --> 07:13:44,558
going to have a problem and sometimes
9987
07:13:44,940 --> 07:13:45,940
we're also going to see it on the 4.6
9988
07:13:46,500 --> 07:13:47,500
gigahertz frequency
9989
07:13:48,660 --> 07:13:49,660
and for those that operate at 2.4
9990
07:13:51,200 --> 07:13:52,200
obviously not only does radio operate at
9991
07:13:54,240 --> 07:13:55,240
those or Wi-Fi connections but also
9992
07:13:56,160 --> 07:13:57,160
phones and so on so there's a lot of
9993
07:13:58,138 --> 07:13:59,138
potential for
9994
07:14:00,540 --> 07:14:01,540
having devices on the same frequency
9995
07:14:02,580 --> 07:14:03,580
that are going to impede its
9996
07:14:04,080 --> 07:14:05,080
communication
9997
07:14:05,638 --> 07:14:06,638
now one other term I want to talk about
9998
07:14:07,378 --> 07:14:08,378
is a term called latency this is we've
9999
07:14:10,680 --> 07:14:11,680
mentioned it a couple times in previous
10000
07:14:11,940 --> 07:14:12,940
modules but I haven't really defined it
10001
07:14:13,740 --> 07:14:14,740
latency is basically the time delay in a
10002
07:14:16,620 --> 07:14:17,620
given system depending on what system
10003
07:14:18,420 --> 07:14:19,420
you're measuring it might mean slightly
10004
07:14:20,040 --> 07:14:21,040
different things so the system we're
10005
07:14:21,718 --> 07:14:22,718
most concerned with is the network
10006
07:14:23,100 --> 07:14:24,100
latency which can be measured in either
10007
07:14:25,320 --> 07:14:26,320
one way or round trip latency and I'm
10008
07:14:28,860 --> 07:14:29,860
sure that you can understand the
10009
07:14:30,180 --> 07:14:31,180
difference there
10010
07:14:32,160 --> 07:14:33,160
the latency is the amount of time it
10011
07:14:34,200 --> 07:14:35,200
takes for data to go from a source to
10012
07:14:36,000 --> 07:14:37,000
destination and we're just dealing with
10013
07:14:38,160 --> 07:14:39,160
bat round trip
10014
07:14:39,840 --> 07:14:40,840
it coming back as well so the round trip
10015
07:14:42,540 --> 07:14:43,540
adds the two one-way totals
10016
07:14:45,840 --> 07:14:46,840
and doesn't include the processing time
10017
07:14:48,058 --> 07:14:49,058
of the packet so only because it's sent
10018
07:14:50,100 --> 07:14:51,100
and then takes a certain amount of time
10019
07:14:51,420 --> 07:14:52,420
to come back doesn't mean that is all
10020
07:14:53,280 --> 07:14:54,280
latency because some of that is how much
10021
07:14:55,378 --> 07:14:56,378
time the computer is spending processing
10022
07:14:57,660 --> 07:14:58,660
that information
10023
07:14:59,458 --> 07:15:00,458
obviously we want lower latency
10024
07:15:04,320 --> 07:15:05,320
and to measure it we can generally use
10025
07:15:06,780 --> 07:15:07,780
the Ping utility which is going to tell
10026
07:15:09,000 --> 07:15:10,000
us in milliseconds how long a packet
10027
07:15:12,180 --> 07:15:13,180
took to go there and come back
10028
07:15:14,280 --> 07:15:15,280
now let's look at some of the 802 11
10029
07:15:16,440 --> 07:15:17,440
standards and see which specifications
10030
07:15:18,780 --> 07:15:19,780
have the least amount of latency so
10031
07:15:21,058 --> 07:15:22,058
these 802 11 standards cover the proper
10032
07:15:24,120 --> 07:15:25,120
implementation setup and performance
10033
07:15:26,340 --> 07:15:27,340
minimums and device specifications for
10034
07:15:29,400 --> 07:15:30,400
wireless local area networks these all
10035
07:15:32,280 --> 07:15:33,280
fall under the 802.11 specifications
10036
07:15:34,920 --> 07:15:35,920
they also specify the method for which
10037
07:15:38,280 --> 07:15:39,280
those wireless networks as carrier sense
10038
07:15:42,000 --> 07:15:43,000
multiple access with collision avoidance
10039
07:15:47,280 --> 07:15:48,280
or csma CA which we've talked about
10040
07:15:51,180 --> 07:15:52,180
are going to operate
10041
07:15:53,280 --> 07:15:54,280
and it also designates the 2.4 gigahertz
10042
07:15:56,218 --> 07:15:57,218
frequency
10043
07:15:58,020 --> 07:15:59,020
as the band for the sped Spectrum
10044
07:16:00,840 --> 07:16:01,840
devices that are going to utilize for
10045
07:16:02,878 --> 07:16:03,878
reliability now over the years there
10046
07:16:04,798 --> 07:16:05,798
have been several standards in this
10047
07:16:06,180 --> 07:16:07,180
family that have been ratified the
10048
07:16:08,040 --> 07:16:09,040
original was 802.11 just plain old it
10049
07:16:10,978 --> 07:16:11,978
was named for its release in 1997 so the
10050
07:16:14,580 --> 07:16:15,580
1997 is part of that and it was
10051
07:16:17,280 --> 07:16:18,280
specified to operate the 2.4 gigahertz
10052
07:16:19,500 --> 07:16:20,500
frequency band and was rated for data
10053
07:16:21,958 --> 07:16:22,958
bits at about 2 megabits per second
10054
07:16:24,000 --> 07:16:25,000
which as you imagine would not be very
10055
07:16:26,340 --> 07:16:27,340
useful for us now and therefore it is
10056
07:16:28,320 --> 07:16:29,320
very obsolete at this point
10057
07:16:30,600 --> 07:16:31,600
the 802 a standard which was released
10058
07:16:33,718 --> 07:16:34,718
two years later was designed to operate
10059
07:16:36,058 --> 07:16:37,058
at the 5 gigahertz band and it had a 54
10060
07:16:39,180 --> 07:16:40,180
megabit data rate now while it would
10061
07:16:41,340 --> 07:16:42,340
seem that this standard would sort of
10062
07:16:42,718 --> 07:16:43,718
lead the charge in Wireless standards at
10063
07:16:44,820 --> 07:16:45,820
the same time that 802a was released
10064
07:16:47,040 --> 07:16:48,040
there was also 802 B which was released
10065
07:16:49,620 --> 07:16:50,620
and 802b operates at the 2.4 gigahertz
10066
07:16:53,040 --> 07:16:54,040
band and essentially was a direct
10067
07:16:55,378 --> 07:16:56,378
extension of the original
10068
07:16:57,680 --> 07:16:58,680
802.11 1997 standard now even though the
10069
07:17:01,620 --> 07:17:02,620
data rate was faster with 802.11a there
10070
07:17:04,500 --> 07:17:05,500
were some initial downsides to that
10071
07:17:06,240 --> 07:17:07,240
standard that kept it from being the
10072
07:17:07,620 --> 07:17:08,620
most popular
10073
07:17:08,878 --> 07:17:09,878
first this higher frequency uh had a
10074
07:17:12,900 --> 07:17:13,900
lesser range and so you could travel
10075
07:17:15,360 --> 07:17:16,360
travel less distance
10076
07:17:19,440 --> 07:17:20,440
also when 802.11b came out it was a lot
10077
07:17:22,978 --> 07:17:23,978
cheaper
10078
07:17:24,540 --> 07:17:25,540
than 802.11a and that made up quickly uh
10079
07:17:28,558 --> 07:17:29,558
with consumers and so it quickly became
10080
07:17:30,900 --> 07:17:31,900
the de facto standard now it's popularly
10081
07:17:33,420 --> 07:17:34,420
grew rapidly and though it operated at
10082
07:17:35,820 --> 07:17:36,820
2.4 gigahertz and therefore was open to
10083
07:17:38,160 --> 07:17:39,160
uh you know was really susceptible
10084
07:17:41,340 --> 07:17:42,340
to a lot of interference uh it still was
10085
07:17:44,940 --> 07:17:45,940
the one that almost everyone used uh and
10086
07:17:47,878 --> 07:17:48,878
so that's sort of where it went because
10087
07:17:49,920 --> 07:17:50,920
range
10088
07:17:52,020 --> 07:17:53,020
was such a big deal the next standard
10089
07:17:54,660 --> 07:17:55,660
which was released in 2003 was the 802
10090
07:17:57,600 --> 07:17:58,600
11g standard and this specification used
10091
07:18:00,540 --> 07:18:01,540
the 2.4 gigahertz frequency again
10092
07:18:03,420 --> 07:18:04,420
but the data rates took a major leap up
10093
07:18:05,580 --> 07:18:06,580
to 54 megabits per second just like
10094
07:18:07,700 --> 07:18:08,700
802.11a now since it used the 2.4 band
10095
07:18:10,978 --> 07:18:11,978
it made backwards compatible with
10096
07:18:13,400 --> 07:18:14,400
802.11b so it was very easy to integrate
10097
07:18:16,920 --> 07:18:17,920
and it therefore became the preferred
10098
07:18:18,840 --> 07:18:19,840
standard now after 80211g took over the
10099
07:18:21,840 --> 07:18:22,840
market it wasn't until 2009 that we
10100
07:18:24,298 --> 07:18:25,298
finally got the 802.11 N standard and it
10101
07:18:27,600 --> 07:18:28,600
was released with something called a
10102
07:18:30,240 --> 07:18:31,240
memo
10103
07:18:31,798 --> 07:18:32,798
which was a type of antenna
10104
07:18:33,958 --> 07:18:34,958
or multiple
10105
07:18:40,138 --> 07:18:41,138
input
10106
07:18:44,760 --> 07:18:45,760
multiple output
10107
07:18:46,440 --> 07:18:47,440
and it had multiple antennas and that
10108
07:18:48,600 --> 07:18:49,600
greatly improved the network performance
10109
07:18:50,540 --> 07:18:51,540
also this amendment was specified for
10110
07:18:53,580 --> 07:18:54,580
both 2.4 gigahertz and 5 gigahertz bands
10111
07:18:56,820 --> 07:18:57,820
and so these improvements made the
10112
07:18:58,740 --> 07:18:59,740
standard really popular especially
10113
07:19:00,718 --> 07:19:01,718
because it was backwards compatible not
10114
07:19:02,940 --> 07:19:03,940
only with G but also with b and even a
10115
07:19:07,798 --> 07:19:08,798
and it was rated for a maximum of up to
10116
07:19:10,320 --> 07:19:11,320
150 megabits per second now the range of
10117
07:19:13,978 --> 07:19:14,978
these Wireless standards is also
10118
07:19:15,660 --> 07:19:16,660
specified the original 802 11 1997 and a
10119
07:19:21,180 --> 07:19:22,180
have a range of about
10120
07:19:24,180 --> 07:19:25,180
20 meters B and G
10121
07:19:28,978 --> 07:19:29,978
have a hundred meters
10122
07:19:31,500 --> 07:19:32,500
and N is approximately 70 meters so we
10123
07:19:34,260 --> 07:19:35,260
lost a little bit of distance because we
10124
07:19:36,360 --> 07:19:37,360
added that five gigahertz band in but
10125
07:19:39,298 --> 07:19:40,298
for most people this didn't really
10126
07:19:41,218 --> 07:19:42,218
matter since we could use again an
10127
07:19:43,378 --> 07:19:44,378
extended service set and simply add
10128
07:19:45,600 --> 07:19:46,600
several 80211 devices
10129
07:19:47,878 --> 07:19:48,878
now while you might have heard of some
10130
07:19:49,620 --> 07:19:50,620
newer standards available and even some
10131
07:19:52,138 --> 07:19:53,138
that are just coming around the corner
10132
07:19:53,458 --> 07:19:54,458
these four are the ones you really need
10133
07:19:56,400 --> 07:19:57,400
to know for the exam and so those are
10134
07:19:58,500 --> 07:19:59,500
the ones I really want to concentrate on
10135
07:20:02,940 --> 07:20:03,940
so if we look at these in a little more
10136
07:20:04,378 --> 07:20:05,378
organized Manner and we can recap the
10137
07:20:06,660 --> 07:20:07,660
important parts the 802.11 standard 1997
10138
07:20:10,260 --> 07:20:11,260
worked on a 9 a 2.4 frequency had a
10139
07:20:14,940 --> 07:20:15,940
range of 20 meters
10140
07:20:16,978 --> 07:20:17,978
and had a two megabit per second data
10141
07:20:19,320 --> 07:20:20,320
rate
10142
07:20:20,040 --> 07:20:21,040
Ada 211A was at 5 gigahertz 20 meters in
10143
07:20:24,000 --> 07:20:25,000
range 54 megabits it's compatible with
10144
07:20:27,740 --> 07:20:28,740
802.11n 8211b operated at 2.4 gigahertz
10145
07:20:32,040 --> 07:20:33,040
had a 100 meter range 11 megabits per
10146
07:20:35,580 --> 07:20:36,580
second and is compatible with G and n
10147
07:20:38,580 --> 07:20:39,580
ative to 11g also 2.4 gigahertz 100
10148
07:20:42,180 --> 07:20:43,180
meters and it was 54 megabits per second
10149
07:20:45,420 --> 07:20:46,420
so it's increasing the top the speed
10150
07:20:48,120 --> 07:20:49,120
and was compatible with the previous and
10151
07:20:51,000 --> 07:20:52,000
the next one which is 802.11n which not
10152
07:20:54,298 --> 07:20:55,298
only operates at 2.4 gigahertz but also
10153
07:20:57,180 --> 07:20:58,180
five
10154
07:20:58,500 --> 07:20:59,500
has a slightly less range but it does
10155
07:21:01,500 --> 07:21:02,500
have a higher megabit per second data
10156
07:21:03,900 --> 07:21:04,900
rate some would even claim that this
10157
07:21:05,458 --> 07:21:06,458
goes up to 600 depending on your
10158
07:21:07,260 --> 07:21:08,260
theoretical and it's compatible with all
10159
07:21:10,558 --> 07:21:11,558
of the previous versions
10160
07:21:13,320 --> 07:21:14,320
now there are two modes that are
10161
07:21:15,840 --> 07:21:16,840
supported by the Ada 211 standard the
10162
07:21:18,058 --> 07:21:19,058
first is what we call infrastructure
10163
07:21:20,160 --> 07:21:21,160
mode this is the mode that's configured
10164
07:21:22,138 --> 07:21:23,138
to use wireless access points to connect
10165
07:21:24,540 --> 07:21:25,540
workstations to a cable backbone
10166
07:21:27,540 --> 07:21:28,540
the network using the infrastructure
10167
07:21:30,120 --> 07:21:31,120
mode is going to either use a basic
10168
07:21:32,760 --> 07:21:33,760
service set or an extended service set
10169
07:21:36,360 --> 07:21:37,360
the other one we have which we already
10170
07:21:37,798 --> 07:21:38,798
mentioned is called ad hoc mode this is
10171
07:21:40,200 --> 07:21:41,200
for those peer-to-peer configurations
10172
07:21:42,900 --> 07:21:43,900
and again it's referred to as an
10173
07:21:45,120 --> 07:21:46,120
independent basic service set or an ibss
10174
07:21:49,080 --> 07:21:50,080
now the configuration of this mode is
10175
07:21:51,540 --> 07:21:52,540
designed with each Wireless workstation
10176
07:21:53,700 --> 07:21:54,700
able to communicate directly with one
10177
07:21:56,340 --> 07:21:57,340
another without having to go through a
10178
07:21:58,200 --> 07:21:59,200
central device
10179
07:22:00,120 --> 07:22:01,120
now earlier in this module we talked
10180
07:22:02,638 --> 07:22:03,638
about the service sets of many kinds and
10181
07:22:04,740 --> 07:22:05,740
we talked about frames in previous
10182
07:22:06,840 --> 07:22:07,840
modules now keeping those in mind it's
10183
07:22:09,058 --> 07:22:10,058
important to understand how these
10184
07:22:10,620 --> 07:22:11,620
devices such as laptops and smartphones
10185
07:22:13,500 --> 07:22:14,500
know what wireless networks are
10186
07:22:15,840 --> 07:22:16,840
available when we access them
10187
07:22:18,360 --> 07:22:19,360
now this comes by detecting and
10188
07:22:20,280 --> 07:22:21,280
receiving what are called Beacon frames
10189
07:22:22,138 --> 07:22:23,138
a beacon frame is a management frame
10190
07:22:24,958 --> 07:22:25,958
that's 50 bytes long and it contains
10191
07:22:27,718 --> 07:22:28,718
information about the transmission
10192
07:22:29,280 --> 07:22:30,280
process such as the SSID or the service
10193
07:22:33,600 --> 07:22:34,600
set identifier
10194
07:22:35,340 --> 07:22:36,340
which is essentially the name of your
10195
07:22:39,180 --> 07:22:40,180
network
10196
07:22:41,040 --> 07:22:42,040
the SSID is that text string that
10197
07:22:44,940 --> 07:22:45,940
identifies the network it's 32 bytes
10198
07:22:47,400 --> 07:22:48,400
long might be for instance Bill's
10199
07:22:49,920 --> 07:22:50,920
Network or something like that now the
10200
07:22:52,558 --> 07:22:53,558
beacon frame is used to start and
10201
07:22:55,440 --> 07:22:56,440
maintain
10202
07:22:56,878 --> 07:22:57,878
the wireless communication session and
10203
07:23:00,058 --> 07:23:01,058
it's sent in regular intervals from the
10204
07:23:02,340 --> 07:23:03,340
axis point and those intervals can be
10205
07:23:04,500 --> 07:23:05,500
manually changed or set by an
10206
07:23:06,180 --> 07:23:07,180
administrator and we can even turn them
10207
07:23:09,120 --> 07:23:10,120
off so that way or hide them so that's
10208
07:23:11,700 --> 07:23:12,700
not being broadcast
10209
07:23:13,558 --> 07:23:14,558
now when it comes to installing a proper
10210
07:23:16,138 --> 07:23:17,138
wireless network implementation we need
10211
07:23:18,360 --> 07:23:19,360
to be familiar with the typical process
10212
07:23:20,280 --> 07:23:21,280
and the steps to maintain the highest
10213
07:23:22,920 --> 07:23:23,920
level of functionality now much like a
10214
07:23:25,740 --> 07:23:26,740
lot of different processes the basic
10215
07:23:27,360 --> 07:23:28,360
steps to take are pretty much the same
10216
07:23:29,400 --> 07:23:30,400
they begin with planning so there are a
10217
07:23:32,100 --> 07:23:33,100
few things that are helpful to collect
10218
07:23:33,600 --> 07:23:34,600
before the planning process
10219
07:23:35,940 --> 07:23:36,940
we need to collect information about the
10220
07:23:38,100 --> 07:23:39,100
floor plan of the building where we want
10221
07:23:40,080 --> 07:23:41,080
to install and so we can design a
10222
07:23:42,120 --> 07:23:43,120
topology and figure out where to put
10223
07:23:43,620 --> 07:23:44,620
access points we need to establish
10224
07:23:46,080 --> 07:23:47,080
requirements for how many devices are
10225
07:23:48,180 --> 07:23:49,180
going to connect which 802.11 standard
10226
07:23:50,878 --> 07:23:51,878
we're going to use what type of security
10227
07:23:52,978 --> 07:23:53,978
is going to be required and so on now
10228
07:23:55,740 --> 07:23:56,740
all of these are crucial to proper
10229
07:23:57,478 --> 07:23:58,478
planning without this information it's
10230
07:23:59,280 --> 07:24:00,280
just going to be easy to choose the
10231
07:24:00,360 --> 07:24:01,360
wrong devices or the wrong Technologies
10232
07:24:03,260 --> 07:24:04,260
also if the research isn't done
10233
07:24:05,700 --> 07:24:06,700
beforehand you're going to find yourself
10234
07:24:07,500 --> 07:24:08,500
performing a lot of rework at the end
10235
07:24:11,218 --> 07:24:12,218
now once this information is designed
10236
07:24:13,320 --> 07:24:14,320
and gathered
10237
07:24:14,760 --> 07:24:15,760
we can start to establish the type of
10238
07:24:16,798 --> 07:24:17,798
access points and the number of APs
10239
07:24:19,200 --> 07:24:20,200
needed knowing the number of users on
10240
07:24:21,360 --> 07:24:22,360
the network is going to help us
10241
07:24:22,558 --> 07:24:23,558
determine for instance how many access
10242
07:24:24,780 --> 07:24:25,780
points and we want to balance the number
10243
07:24:27,058 --> 07:24:28,058
of users with the access points in order
10244
07:24:28,860 --> 07:24:29,860
to make sure that we have a good load
10245
07:24:31,020 --> 07:24:32,020
balance
10246
07:24:31,920 --> 07:24:32,920
the next step is to assess the building
10247
07:24:34,320 --> 07:24:35,320
to see if anything around might cause
10248
07:24:36,420 --> 07:24:37,420
interference
10249
07:24:37,860 --> 07:24:38,860
specifically it's important to install
10250
07:24:39,718 --> 07:24:40,718
anything that's going to be on the 2.4
10251
07:24:41,820 --> 07:24:42,820
gigahertz band now remember some of the
10252
07:24:44,040 --> 07:24:45,040
things that can cause interference are
10253
07:24:45,840 --> 07:24:46,840
Bluetooth devices other wireless
10254
07:24:47,520 --> 07:24:48,520
networks heavy duty machinery and so on
10255
07:24:51,058 --> 07:24:52,058
we also need to determine the exact
10256
07:24:53,400 --> 07:24:54,400
placement of the access points are they
10257
07:24:55,620 --> 07:24:56,620
going to be placed in the ceiling or
10258
07:24:56,878 --> 07:24:57,878
somewhere visible or somewhere like a
10259
07:24:59,100 --> 07:25:00,100
secure room and when we determine this
10260
07:25:01,260 --> 07:25:02,260
we need to make sure that there's we're
10261
07:25:03,120 --> 07:25:04,120
looking for obstacles that are going to
10262
07:25:04,798 --> 07:25:05,798
impede like thick walls doors metal
10263
07:25:07,558 --> 07:25:08,558
shelving uh proximity to large
10264
07:25:10,798 --> 07:25:11,798
electrical equipment and if those
10265
07:25:12,900 --> 07:25:13,900
obstacles Can't Be Moved we might want
10266
07:25:14,760 --> 07:25:15,760
to choose a different location for our
10267
07:25:16,440 --> 07:25:17,440
access point
10268
07:25:17,580 --> 07:25:18,580
so now that we've planned the next part
10269
07:25:19,200 --> 07:25:20,200
is the fun part the actual installation
10270
07:25:21,718 --> 07:25:22,718
here we need to configure the device to
10271
07:25:24,900 --> 07:25:25,900
connect it to the network and some of
10272
07:25:26,458 --> 07:25:27,458
the standard things we're going to do
10273
07:25:27,360 --> 07:25:28,360
are connect the router
10274
07:25:29,280 --> 07:25:30,280
change the administrator default
10275
07:25:31,860 --> 07:25:32,860
settings that the device came with and
10276
07:25:34,680 --> 07:25:35,680
configure DHCP services and encryption
10277
07:25:37,440 --> 07:25:38,440
levels such as whether we're going to
10278
07:25:39,600 --> 07:25:40,600
use WPA
10279
07:25:44,160 --> 07:25:45,160
or WEP and also are we going to use one
10280
07:25:48,180 --> 07:25:49,180
of the three channels are we going to
10281
07:25:49,440 --> 07:25:50,440
have them auto check or what another
10282
07:25:51,840 --> 07:25:52,840
thing we might want to do is create
10283
07:25:52,920 --> 07:25:53,920
what's called an access control list
10284
07:25:54,958 --> 07:25:55,958
which means we can allow only specific
10285
07:25:58,740 --> 07:25:59,740
computers to get access to our
10286
07:26:01,080 --> 07:26:02,080
network via Mac addresses which are
10287
07:26:04,440 --> 07:26:05,440
again the physical addresses on a
10288
07:26:06,780 --> 07:26:07,780
computer
10289
07:26:07,798 --> 07:26:08,798
or on a network card
10290
07:26:13,740 --> 07:26:14,740
next we need to configure the client
10291
07:26:15,958 --> 07:26:16,958
workstations and we need to test your
10292
07:26:18,240 --> 07:26:19,240
functionality now it's important here
10293
07:26:20,580 --> 07:26:21,580
because not all operating systems can
10294
07:26:23,100 --> 07:26:24,100
use all the different standards they
10295
07:26:24,540 --> 07:26:25,540
might even require a software update of
10296
07:26:26,760 --> 07:26:27,760
some sort
10297
07:26:28,260 --> 07:26:29,260
you might want to make sure to test the
10298
07:26:30,958 --> 07:26:31,958
wireless device by walking around a
10299
07:26:32,820 --> 07:26:33,820
building and make sure you can stay
10300
07:26:34,680 --> 07:26:35,680
connected and that you can connect in
10301
07:26:36,058 --> 07:26:37,058
the first place anywhere you need to and
10302
07:26:38,340 --> 07:26:39,340
then you also need to take the device
10303
07:26:39,840 --> 07:26:40,840
outside and make sure that no one can
10304
07:26:42,120 --> 07:26:43,120
get in from the outside so it's actually
10305
07:26:44,160 --> 07:26:45,160
quite difficult to just start one of
10306
07:26:46,138 --> 07:26:47,138
these from scratch the last step in the
10307
07:26:48,420 --> 07:26:49,420
process is to document every single step
10308
07:26:50,878 --> 07:26:51,878
that was made and it's always a good
10309
07:26:52,680 --> 07:26:53,680
idea to Baseline for future testing and
10310
07:26:54,958 --> 07:26:55,958
implementations now being able to
10311
07:26:57,240 --> 07:26:58,240
successfully accomplish the two phases
10312
07:26:59,520 --> 07:27:00,520
the planning phase and the installation
10313
07:27:01,860 --> 07:27:02,860
phase needs to be a part of your skill
10314
07:27:03,958 --> 07:27:04,958
set needs to be something you understand
10315
07:27:05,340 --> 07:27:06,340
for the network plus exam so just to
10316
07:27:07,920 --> 07:27:08,920
recap everything we've talked about the
10317
07:27:09,900 --> 07:27:10,900
first thing we did is we outlined the
10318
07:27:11,218 --> 07:27:12,218
different types of ethernet networks
10319
07:27:13,500 --> 07:27:14,500
whether that means it's a Hub Network
10320
07:27:17,520 --> 07:27:18,520
a router Network
10321
07:27:19,440 --> 07:27:20,440
or a peer-to-peer Network
10322
07:27:24,058 --> 07:27:25,058
we also explained WLAN architecture
10323
07:27:27,298 --> 07:27:28,298
looking at the difference between a
10324
07:27:29,218 --> 07:27:30,218
basic service set an extended service
10325
07:27:31,440 --> 07:27:32,440
set and an independent basic service set
10326
07:27:35,280 --> 07:27:36,280
we defined and describe the
10327
07:27:36,780 --> 07:27:37,780
characteristics of antennas looking at
10328
07:27:39,478 --> 07:27:40,478
gain
10329
07:27:40,860 --> 07:27:41,860
and the types of impedances that could
10330
07:27:43,558 --> 07:27:44,558
occur
10331
07:27:46,558 --> 07:27:47,558
then we outline the Ada to 11 standard
10332
07:27:49,820 --> 07:27:50,820
including a b g and N which are the
10333
07:27:54,958 --> 07:27:55,958
different modes
10334
07:27:56,878 --> 07:27:57,878
we also talked about which frequencies
10335
07:27:59,400 --> 07:28:00,400
these live on whether 2.4 or 5
10336
07:28:03,660 --> 07:28:04,660
and how fast are the megabits per second
10337
07:28:06,540 --> 07:28:07,540
that each one provides you want to make
10338
07:28:09,000 --> 07:28:10,000
sure to commit to memory that table that
10339
07:28:10,860 --> 07:28:11,860
we displayed on an earlier frame
10340
07:28:14,040 --> 07:28:15,040
we also talked about defining Beacon
10341
07:28:16,200 --> 07:28:17,200
frames which broadcast the SSID and tell
10342
07:28:20,100 --> 07:28:21,100
computers how to connect to the wireless
10343
07:28:22,080 --> 07:28:23,080
network
10344
07:28:23,520 --> 07:28:24,520
finally we outlined what factors are
10345
07:28:26,280 --> 07:28:27,280
going to result in where you place your
10346
07:28:28,320 --> 07:28:29,320
access point and how to properly
10347
07:28:30,840 --> 07:28:31,840
Implement a wireless network point
10348
07:28:33,420 --> 07:28:34,420
from the planning
10349
07:28:35,638 --> 07:28:36,638
and implementation stages
10350
07:28:43,660 --> 07:28:44,660
[Music]
10351
07:28:58,558 --> 07:28:59,558
welcome to module 5 lesson five
10352
07:29:01,340 --> 07:29:02,340
IEEE 802.11 AC actually we're going to
10353
07:29:05,760 --> 07:29:06,760
look at a little bit more than that the
10354
07:29:08,458 --> 07:29:09,458
N standard 82.11n
10355
07:29:11,520 --> 07:29:12,520
AC Channel bonding
10356
07:29:15,360 --> 07:29:16,360
now the 802.11 it's a specification for
10357
07:29:19,200 --> 07:29:20,200
wireless LAN WLAN communication it uses
10358
07:29:23,040 --> 07:29:24,040
mimo which we shorten from a multiple
10359
07:29:26,820 --> 07:29:27,820
input multiple outputs I'm sure you can
10360
07:29:29,638 --> 07:29:30,638
see why
10361
07:29:31,500 --> 07:29:32,500
so in this technology the transmitter
10362
07:29:34,138 --> 07:29:35,138
and receiver use multiple antennas
10363
07:29:38,218 --> 07:29:39,218
I've put a little diagram on the bottom
10364
07:29:40,138 --> 07:29:41,138
here from um ieb media
10365
07:29:43,500 --> 07:29:44,500
that it will demonstrate at the bottom
10366
07:29:45,780 --> 07:29:46,780
certainly you can see three channels in
10367
07:29:47,638 --> 07:29:48,638
use simultaneously multiple channels on
10368
07:29:51,058 --> 07:29:52,058
the top part of the Fig you can see you
10369
07:29:54,298 --> 07:29:55,298
can select from but it's only using one
10370
07:29:57,058 --> 07:29:58,058
so in this standard the end standard
10371
07:29:59,340 --> 07:30:00,340
multiple antennas provide independent
10372
07:30:01,558 --> 07:30:02,558
paths in space between the transmitter
10373
07:30:03,360 --> 07:30:04,360
and the receiver
10374
07:30:05,040 --> 07:30:06,040
to send or receive streams of
10375
07:30:07,680 --> 07:30:08,680
information at the same time on the same
10376
07:30:09,958 --> 07:30:10,958
band
10377
07:30:10,798 --> 07:30:11,798
what my mode does is increase the number
10378
07:30:12,780 --> 07:30:13,780
of data streams sent from an access
10379
07:30:14,340 --> 07:30:15,340
point to a client which you can see in
10380
07:30:16,378 --> 07:30:17,378
the bottom part
10381
07:30:18,600 --> 07:30:19,600
in 802.11 mimo four spatial streams can
10382
07:30:22,200 --> 07:30:23,200
be sent to a single client at a time
10383
07:30:25,440 --> 07:30:26,440
again if you want to read further you
10384
07:30:27,360 --> 07:30:28,360
can now look up the specifications
10385
07:30:28,860 --> 07:30:29,860
there's a few Wireless specialty books
10386
07:30:31,500 --> 07:30:32,500
if it's something you're interested in
10387
07:30:33,120 --> 07:30:34,120
doing it's certainly an interesting
10388
07:30:34,680 --> 07:30:35,680
field
10389
07:30:36,298 --> 07:30:37,298
uh the 802.11 AC is an enhancement of um
10390
07:30:40,558 --> 07:30:41,558
11n
10391
07:30:42,058 --> 07:30:43,058
obviously still Wireless networking it's
10392
07:30:44,580 --> 07:30:45,580
designed for high throughput our
10393
07:30:46,920 --> 07:30:47,920
wireless Lans on the five gigahertz band
10394
07:30:49,740 --> 07:30:50,740
there's a few advantages to using that
10395
07:30:53,280 --> 07:30:54,280
it uses a multi-user form of Mimo
10396
07:30:58,320 --> 07:30:59,320
in their mind mode the access points has
10397
07:31:00,298 --> 07:31:01,298
multiple streams of data at the same
10398
07:31:02,340 --> 07:31:03,340
time to different clients over the same
10399
07:31:04,620 --> 07:31:05,620
frequency spectrum
10400
07:31:06,420 --> 07:31:07,420
in uh 802.11 acmu mimo eight special
10401
07:31:12,000 --> 07:31:13,000
streams can be divided among up to four
10402
07:31:15,120 --> 07:31:16,120
clients I think the MU is multiple user
10403
07:31:19,320 --> 07:31:20,320
yeah multi-user mimo at the bottom and
10404
07:31:21,660 --> 07:31:22,660
you can see the stream can be broken up
10405
07:31:24,298 --> 07:31:25,298
you've got a few options you can have a
10406
07:31:26,760 --> 07:31:27,760
higher stream to one client and then
10407
07:31:29,040 --> 07:31:30,040
lower bandwidth stream to another
10408
07:31:31,020 --> 07:31:32,020
clients
10409
07:31:34,620 --> 07:31:35,620
supports treatment of HD videos which is
10410
07:31:37,200 --> 07:31:38,200
really handy and to multiple clients
10411
07:31:39,058 --> 07:31:40,058
because of low latency high throughput
10412
07:31:41,160 --> 07:31:42,160
and reliability
10413
07:31:43,378 --> 07:31:44,378
it operates in the five gigahertz band I
10414
07:31:46,378 --> 07:31:47,378
already mentioned that theoretical data
10415
07:31:48,478 --> 07:31:49,478
rate of 600 this has been improved on
10416
07:31:50,520 --> 07:31:51,520
all the time so maybe check up on the um
10417
07:31:53,940 --> 07:31:54,940
standard before exam day
10418
07:31:58,260 --> 07:31:59,260
you've got less interference than in the
10419
07:32:00,600 --> 07:32:01,600
2.4 gigahertz band which is where you
10420
07:32:03,360 --> 07:32:04,360
get the increased performance more
10421
07:32:05,400 --> 07:32:06,400
channels available for data transmission
10422
07:32:07,580 --> 07:32:08,580
greater number of non-overlapping
10423
07:32:10,020 --> 07:32:11,020
channels than you do in 2.4 megahertz I
10424
07:32:13,558 --> 07:32:14,558
think there's a couple of disadvantages
10425
07:32:15,058 --> 07:32:16,058
as well but I'm not sure I'll put them
10426
07:32:16,860 --> 07:32:17,860
down here in the slide
10427
07:32:18,600 --> 07:32:19,600
so the U.S a five gigahertz band has 25
10428
07:32:21,740 --> 07:32:22,740
non-overlapping channels whereas 2.4
10429
07:32:24,540 --> 07:32:25,540
gigahertz is only three
10430
07:32:29,760 --> 07:32:30,760
uh Channel bandwidth of the following 80
10431
07:32:31,798 --> 07:32:32,798
160 20 it's worth and making a note of
10432
07:32:35,100 --> 07:32:36,100
all of these in case it's asked in the
10433
07:32:36,660 --> 07:32:37,660
exam and 40.
10434
07:32:40,138 --> 07:32:41,138
uh obviously needs to comply with the
10435
07:32:42,660 --> 07:32:43,660
standard you can see this particular
10436
07:32:43,978 --> 07:32:44,978
adapter's got it written on it it's got
10437
07:32:45,840 --> 07:32:46,840
a AC standard written on it
10438
07:32:48,780 --> 07:32:49,780
to comply with the standard as to
10439
07:32:50,638 --> 07:32:51,638
support the 2040 80 megahertz Channel
10440
07:32:53,638 --> 07:32:54,638
bandwidth in the 5 gigahertz band
10441
07:32:56,820 --> 07:32:57,820
the 160 megahertz Channel bandwidth is
10442
07:32:59,458 --> 07:33:00,458
optional
10443
07:33:01,320 --> 07:33:02,320
80 megahertz channels are formed by
10444
07:33:03,240 --> 07:33:04,240
combining combining the following
10445
07:33:04,558 --> 07:33:05,558
following two adjacent none overlapping
10446
07:33:07,500 --> 07:33:08,500
40 megahertz
10447
07:33:10,020 --> 07:33:11,020
160 megahertz are uh combined to 80
10448
07:33:13,920 --> 07:33:14,920
megahertz I think you can see how this
10449
07:33:15,718 --> 07:33:16,718
works
10450
07:33:17,760 --> 07:33:18,760
so here I've put
10451
07:33:19,558 --> 07:33:20,558
um
10452
07:33:20,400 --> 07:33:21,400
a slide from Wi-Fi Jetty website they've
10453
07:33:24,540 --> 07:33:25,540
combined two channels here to 20
10454
07:33:26,760 --> 07:33:27,760
megahertz channels are made of 40 for
10455
07:33:28,920 --> 07:33:29,920
channel bonding
10456
07:33:31,798 --> 07:33:32,798
so Channel bonding was first introduced
10457
07:33:34,020 --> 07:33:35,020
with 802.11n
10458
07:33:36,660 --> 07:33:37,660
in Channel bonding two or more channels
10459
07:33:38,638 --> 07:33:39,638
adjacent to each other are combined to
10460
07:33:40,740 --> 07:33:41,740
increase bandwidth as you can see in the
10461
07:33:42,478 --> 07:33:43,478
figure put there
10462
07:33:44,638 --> 07:33:45,638
benefits 802.11 AC benefits because it
10463
07:33:47,820 --> 07:33:48,820
supports the following channels 2040
10464
07:33:51,058 --> 07:33:52,058
80 megahertz
10465
07:33:54,020 --> 07:33:55,020
uh although 160 megahertz channels are
10466
07:33:57,240 --> 07:33:58,240
supported as an option is its
10467
07:33:59,160 --> 07:34:00,160
availability depends on your geography
10468
07:34:01,260 --> 07:34:02,260
Where You Are
10469
07:34:03,180 --> 07:34:04,180
well I just had a bandwidth increases
10470
07:34:04,978 --> 07:34:05,978
the data rates so
10471
07:34:07,378 --> 07:34:08,378
um 11ac uses eight spatial streams and
10472
07:34:09,660 --> 07:34:10,660
160 megahertz bandwidth
10473
07:34:12,660 --> 07:34:13,660
to achieve a maximum data rate of 6.933
10474
07:34:16,320 --> 07:34:17,320
gig
10475
07:34:18,360 --> 07:34:19,360
uh data rates vary on the following for
10476
07:34:20,878 --> 07:34:21,878
11ac you're given bandwidth and the
10477
07:34:23,400 --> 07:34:24,400
number of spatial streams used
10478
07:34:26,520 --> 07:34:27,520
probably worth um writing out this
10479
07:34:29,580 --> 07:34:30,580
um
10480
07:34:31,020 --> 07:34:32,020
table here if you want the information
10481
07:34:33,600 --> 07:34:34,600
or you can do a screen capture
10482
07:34:36,798 --> 07:34:37,798
802.11 AC with one spatial stream and
10483
07:34:39,840 --> 07:34:40,840
for a bandwidth of 20 megahertz can
10484
07:34:41,520 --> 07:34:42,520
ensure either data rate of
10485
07:34:43,638 --> 07:34:44,638
86.7 megahertz and so on and so forth
10486
07:34:47,280 --> 07:34:48,280
for the others um their data rate
10487
07:34:49,920 --> 07:34:50,920
increases both vertically and
10488
07:34:51,958 --> 07:34:52,958
horizontally
10489
07:34:53,520 --> 07:34:54,520
all right so we've covered NAC Channel
10490
07:34:56,100 --> 07:34:57,100
bonding that's all for now thanks for
10491
07:34:58,558 --> 07:34:59,558
listening
10492
07:35:02,230 --> 07:35:03,230
[Music]
10493
07:35:18,660 --> 07:35:19,660
plug the module 5 lesson 6 in network
10494
07:35:21,780 --> 07:35:22,780
segmentation
10495
07:35:24,718 --> 07:35:25,718
quite a bit to cover and some of this is
10496
07:35:26,878 --> 07:35:27,878
a little bit esoteric to be honest so um
10497
07:35:30,000 --> 07:35:31,000
it's conceptual
10498
07:35:32,040 --> 07:35:33,040
it can be a bit hard to get your head
10499
07:35:33,780 --> 07:35:34,780
around
10500
07:35:34,860 --> 07:35:35,860
um in that sense
10501
07:35:36,660 --> 07:35:37,660
what is Network segmentation what is
10502
07:35:39,120 --> 07:35:40,120
physical segmentation logical
10503
07:35:42,478 --> 07:35:43,478
uh the uses why bother
10504
07:35:45,058 --> 07:35:46,058
and critical situations so we're hitting
10505
07:35:47,878 --> 07:35:48,878
a few the syllabus topics here in the um
10506
07:35:51,718 --> 07:35:52,718
Network plus syllabus so
10507
07:35:54,718 --> 07:35:55,718
in a sense Network segmentation concerns
10508
07:35:58,260 --> 07:35:59,260
dividing a computer into Network or sub
10509
07:36:00,420 --> 07:36:01,420
networks not in the sense of
10510
07:36:03,180 --> 07:36:04,180
um subnetting
10511
07:36:04,620 --> 07:36:05,620
um in the context of Ip addressing but
10512
07:36:07,680 --> 07:36:08,680
um dividing our network down
10513
07:36:10,860 --> 07:36:11,860
so each portion of the network is called
10514
07:36:14,458 --> 07:36:15,458
a network segment
10515
07:36:16,200 --> 07:36:17,200
it can be characterized by a physical
10516
07:36:18,058 --> 07:36:19,058
boundary
10517
07:36:19,440 --> 07:36:20,440
or logical So Physical something you can
10518
07:36:22,440 --> 07:36:23,440
see logical something that the network
10519
07:36:24,780 --> 07:36:25,780
can see but you couldn't see physically
10520
07:36:27,420 --> 07:36:28,420
you would then have to log in and check
10521
07:36:29,280 --> 07:36:30,280
the configurations
10522
07:36:31,020 --> 07:36:32,020
so physical or logical boundary
10523
07:36:32,820 --> 07:36:33,820
separates various Network segments from
10524
07:36:36,058 --> 07:36:37,058
one another
10525
07:36:38,340 --> 07:36:39,340
physical is a bit easier the computer is
10526
07:36:41,400 --> 07:36:42,400
divided into segments for example with
10527
07:36:43,440 --> 07:36:44,440
switches
10528
07:36:45,020 --> 07:36:46,020
routers a group of physical access and
10529
07:36:48,540 --> 07:36:49,540
assets is part of a specific Network
10530
07:36:51,000 --> 07:36:52,000
segment
10531
07:36:52,320 --> 07:36:53,320
so a bit harder to do with switches
10532
07:36:54,958 --> 07:36:55,958
because you would normally needed to add
10533
07:36:57,420 --> 07:36:58,420
a configuration because switches are
10534
07:36:59,160 --> 07:37:00,160
designed to broadcast to other
10535
07:37:02,700 --> 07:37:03,700
um parts of the network if it doesn't
10536
07:37:04,798 --> 07:37:05,798
know where that part of the network is
10537
07:37:06,478 --> 07:37:07,478
or particularly device
10538
07:37:08,458 --> 07:37:09,458
whereas routers do the opposite
10539
07:37:11,160 --> 07:37:12,160
computer network is logically
10540
07:37:14,218 --> 07:37:15,218
um
10541
07:37:14,940 --> 07:37:15,940
virtually divided into Network segment
10542
07:37:17,218 --> 07:37:18,218
so this is uh from The Logical
10543
07:37:19,020 --> 07:37:20,020
standpoint so we could do it with
10544
07:37:21,478 --> 07:37:22,478
virtual lands or vlans
10545
07:37:23,700 --> 07:37:24,700
virtual segmentation is done or
10546
07:37:25,860 --> 07:37:26,860
different connections or the same
10547
07:37:27,058 --> 07:37:28,058
physical switch so you can have 10
10548
07:37:29,100 --> 07:37:30,100
switch ports and the first five ports
10549
07:37:32,638 --> 07:37:33,638
are in one logical part of the network
10550
07:37:34,440 --> 07:37:35,440
in one VLAN VLAN 10 for example and the
10551
07:37:37,680 --> 07:37:38,680
other five in VLAN 20. and you could
10552
07:37:40,260 --> 07:37:41,260
have multiple vlans depending on your
10553
07:37:42,900 --> 07:37:43,900
capabilities or whatever switch you're
10554
07:37:44,760 --> 07:37:45,760
using
10555
07:37:46,378 --> 07:37:47,378
through through Network segments are
10556
07:37:48,840 --> 07:37:49,840
isolated although secure communication
10557
07:37:51,000 --> 07:37:52,000
can be established between them to share
10558
07:37:53,580 --> 07:37:54,580
network resources we cover that with
10559
07:37:55,680 --> 07:37:56,680
security and elsewhere you can actually
10560
07:37:58,260 --> 07:37:59,260
have an internal and external network
10561
07:38:00,958 --> 07:38:01,958
security it isn't just for example vpns
10562
07:38:03,900 --> 07:38:04,900
connecting and through from remote
10563
07:38:06,120 --> 07:38:07,120
offices
10564
07:38:07,558 --> 07:38:08,558
so why would you bother in a sense it
10565
07:38:11,218 --> 07:38:12,218
enhances the security of the network you
10566
07:38:13,860 --> 07:38:14,860
can isolate critical parts of your
10567
07:38:15,840 --> 07:38:16,840
infrastructure from an authorized access
10568
07:38:18,360 --> 07:38:19,360
for example if you've got a special
10569
07:38:20,820 --> 07:38:21,820
service and server you can restrict
10570
07:38:23,458 --> 07:38:24,458
access to the um users don't access it
10571
07:38:26,638 --> 07:38:27,638
and they don't have direct access so
10572
07:38:28,920 --> 07:38:29,920
they'll be in a different VLAN for
10573
07:38:30,478 --> 07:38:31,478
example or just in it wouldn't appear on
10574
07:38:32,638 --> 07:38:33,638
the network and you normally or may well
10575
07:38:35,400 --> 07:38:36,400
have depending on the size of your
10576
07:38:36,718 --> 07:38:37,718
network a different team or Department
10577
07:38:39,000 --> 07:38:40,000
managing that part of the network
10578
07:38:42,180 --> 07:38:43,180
it can be used for reducing Network
10579
07:38:44,580 --> 07:38:45,580
congestion so you're dedicating certain
10580
07:38:46,740 --> 07:38:47,740
parts of bandwidth for certain segments
10581
07:38:49,080 --> 07:38:50,080
of the network and you can even have a
10582
07:38:51,058 --> 07:38:52,058
high-speed department for example
10583
07:38:54,120 --> 07:38:55,120
um the company I used to work at we had
10584
07:38:55,620 --> 07:38:56,620
a design team who all used
10585
07:38:58,320 --> 07:38:59,320
um high speed high resolution files and
10586
07:39:02,040 --> 07:39:03,040
graphics and it um they needed
10587
07:39:05,280 --> 07:39:06,280
um a fast connection so they had their
10588
07:39:06,780 --> 07:39:07,780
own logical segment
10589
07:39:09,240 --> 07:39:10,240
and you could also limit traffic as I
10590
07:39:11,638 --> 07:39:12,638
said faster connection for some slower
10591
07:39:13,620 --> 07:39:14,620
for others and the available bandwidth
10592
07:39:15,840 --> 07:39:16,840
is um increased or reduced accordingly
10593
07:39:19,798 --> 07:39:20,798
uh also useful for load balancing you
10594
07:39:22,860 --> 07:39:23,860
can distribute the traffic a load based
10595
07:39:25,320 --> 07:39:26,320
on the
10596
07:39:26,280 --> 07:39:27,280
for the network certain devices certain
10597
07:39:29,638 --> 07:39:30,638
devices can be placed in certain
10598
07:39:31,260 --> 07:39:32,260
segments
10599
07:39:33,260 --> 07:39:34,260
and network segmentation is also done
10600
07:39:36,000 --> 07:39:37,000
for the PCI the payment card industry
10601
07:39:38,580 --> 07:39:39,580
that's different from the PCI bus
10602
07:39:40,920 --> 07:39:41,920
technology which we discuss elsewhere
10603
07:39:43,740 --> 07:39:44,740
the PCA compliance standards were
10604
07:39:45,780 --> 07:39:46,780
created by Major card issuers and you
10605
07:39:48,478 --> 07:39:49,478
may come across it if you have to take
10606
07:39:50,400 --> 07:39:51,400
online payments
10607
07:39:53,700 --> 07:39:54,700
um depending on the processor you use
10608
07:39:55,500 --> 07:39:56,500
even if you've got a small
10609
07:39:57,840 --> 07:39:58,840
um Network for your business or shop you
10610
07:40:01,500 --> 07:40:02,500
um may have to or you will be affected
10611
07:40:03,298 --> 07:40:04,298
by PCR compliance
10612
07:40:05,280 --> 07:40:06,280
so this is to ensure that the payment
10613
07:40:06,660 --> 07:40:07,660
transactions are done in a secure
10614
07:40:08,580 --> 07:40:09,580
environment
10615
07:40:10,500 --> 07:40:11,500
if someone processes stores or transmits
10616
07:40:13,020 --> 07:40:14,020
credit card information it must comply
10617
07:40:15,600 --> 07:40:16,600
with the PCI Data security standard
10618
07:40:17,638 --> 07:40:18,638
which is the DSs
10619
07:40:20,820 --> 07:40:21,820
this is mandated by Visa Mastercard
10620
07:40:23,218 --> 07:40:24,218
American Express discovering JCB
10621
07:40:25,440 --> 07:40:26,440
obviously because people will try and
10622
07:40:27,360 --> 07:40:28,360
capture
10623
07:40:28,320 --> 07:40:29,320
and credit card information so it needs
10624
07:40:30,540 --> 07:40:31,540
to comply with the standards
10625
07:40:35,458 --> 07:40:36,458
um Network segmentation is actually not
10626
07:40:37,620 --> 07:40:38,620
a PCI DSS requirement it's done to
10627
07:40:40,020 --> 07:40:41,020
isolate the traffic that stores
10628
07:40:41,958 --> 07:40:42,958
processes or channels emits the card
10629
07:40:44,100 --> 07:40:45,100
holder information from the rest of the
10630
07:40:45,660 --> 07:40:46,660
network
10631
07:40:47,218 --> 07:40:48,218
and reduces the scope of the network
10632
07:40:49,080 --> 07:40:50,080
environment subject to PCI compliance if
10633
07:40:52,260 --> 07:40:53,260
you didn't have your network segmented
10634
07:40:54,478 --> 07:40:55,478
then your entire network would have to
10635
07:40:57,360 --> 07:40:58,360
comply with all of the various pcid SS
10636
07:41:00,958 --> 07:41:01,958
requirements if you segment the card
10637
07:41:03,540 --> 07:41:04,540
processing and part of your network then
10638
07:41:06,180 --> 07:41:07,180
only that part of the network needs to
10639
07:41:07,920 --> 07:41:08,920
comply so it's going to make your life a
10640
07:41:09,660 --> 07:41:10,660
lot easier
10641
07:41:11,580 --> 07:41:12,580
um uses the footprints of a sensitive
10642
07:41:13,500 --> 07:41:14,500
information is confined and this is what
10643
07:41:15,540 --> 07:41:16,540
I I mentioned a moment ago and you can
10644
07:41:17,700 --> 07:41:18,700
protect it using firewall or your
10645
07:41:19,978 --> 07:41:20,978
intrusion detection or Protection
10646
07:41:22,138 --> 07:41:23,138
Systems
10647
07:41:25,200 --> 07:41:26,200
and reduces the audit cost as well
10648
07:41:27,900 --> 07:41:28,900
the audit is done for specific Network
10649
07:41:29,638 --> 07:41:30,638
segment as opposed to your entire
10650
07:41:32,218 --> 07:41:33,218
network and again the best example is
10651
07:41:34,320 --> 07:41:35,320
when you're getting audited for the
10652
07:41:36,058 --> 07:41:37,058
purposes of of PCI compliance
10653
07:41:40,580 --> 07:41:41,580
and this is one of the uh topics for
10654
07:41:44,458 --> 07:41:45,458
these syllabus actually Network segment
10655
07:41:46,200 --> 07:41:47,200
segmentations
10656
07:41:48,360 --> 07:41:49,360
in critical situations numerous
10657
07:41:51,058 --> 07:41:52,058
situations where the network
10658
07:41:52,020 --> 07:41:53,020
segmentation is critical
10659
07:41:54,420 --> 07:41:55,420
so the scada the supervisory control and
10660
07:41:57,780 --> 07:41:58,780
data acquisition and the ICS industrial
10661
07:42:01,860 --> 07:42:02,860
Control Systems so again you'll see
10662
07:42:03,958 --> 07:42:04,958
you'll see this on the syllabus when you
10663
07:42:05,458 --> 07:42:06,458
look the ICS refers to several control
10664
07:42:08,160 --> 07:42:09,160
systems that are used in the industry in
10665
07:42:11,100 --> 07:42:12,100
various Industries this is an industrial
10666
07:42:13,620 --> 07:42:14,620
control system so you may not have heard
10667
07:42:16,798 --> 07:42:17,798
of this or may never come to deal or
10668
07:42:19,558 --> 07:42:20,558
support or manage this unless you're
10669
07:42:21,120 --> 07:42:22,120
part of the industrial Network
10670
07:42:23,520 --> 07:42:24,520
infrastructure
10671
07:42:25,378 --> 07:42:26,378
thank you
10672
07:42:28,020 --> 07:42:29,020
and the additional facilities are
10673
07:42:30,180 --> 07:42:31,180
electrical electrical power grids water
10674
07:42:32,280 --> 07:42:33,280
distribution oil natural gas pipeline
10675
07:42:35,040 --> 07:42:36,040
systems
10676
07:42:36,360 --> 07:42:37,360
and they're dependent on electrical
10677
07:42:38,280 --> 07:42:39,280
hydraulic and mechanical equipment
10678
07:42:41,040 --> 07:42:42,040
this equipment is all monitored by
10679
07:42:42,840 --> 07:42:43,840
sensors that transform the physical
10680
07:42:44,820 --> 07:42:45,820
stimulus for example something's broken
10681
07:42:47,100 --> 07:42:48,100
or stuck
10682
07:42:48,478 --> 07:42:49,478
or doing too much or too little of what
10683
07:42:51,420 --> 07:42:52,420
it should be doing and this is
10684
07:42:53,700 --> 07:42:54,700
um changed into electrical signal
10685
07:42:57,780 --> 07:42:58,780
and in a basic SC Ada system when
10686
07:43:00,840 --> 07:43:01,840
industrial operations are performed the
10687
07:43:02,700 --> 07:43:03,700
information from the sensors is sent to
10688
07:43:05,400 --> 07:43:06,400
a a controller or a number of
10689
07:43:08,100 --> 07:43:09,100
controllers the controller is a type of
10690
07:43:10,798 --> 07:43:11,798
computer that receives the information
10691
07:43:12,260 --> 07:43:13,260
from the sensor
10692
07:43:15,058 --> 07:43:16,058
now what happens with this information
10693
07:43:16,558 --> 07:43:17,558
just depends on the environment and
10694
07:43:18,600 --> 07:43:19,600
what's required and the sensor type it
10695
07:43:21,000 --> 07:43:22,000
sends the information to computers with
10696
07:43:22,740 --> 07:43:23,740
the seada software
10697
07:43:26,760 --> 07:43:27,760
so this helps the systems monitor
10698
07:43:30,120 --> 07:43:31,120
interact and control a variety of
10699
07:43:32,280 --> 07:43:33,280
equipment
10700
07:43:33,840 --> 07:43:34,840
prevents outside attacks the um seida
10701
07:43:37,680 --> 07:43:38,680
systems are segmented from the rest of
10702
07:43:39,240 --> 07:43:40,240
the network
10703
07:43:40,260 --> 07:43:41,260
and in addition they have the firewalls
10704
07:43:42,718 --> 07:43:43,718
installed
10705
07:43:44,160 --> 07:43:45,160
you'd need probably help from a
10706
07:43:46,138 --> 07:43:47,138
specialist and design company and
10707
07:43:49,080 --> 07:43:50,080
probably installation as well because
10708
07:43:50,520 --> 07:43:51,520
it's kind of outside the purview of the
10709
07:43:52,860 --> 07:43:53,860
normal Network Engineers roles
10710
07:43:56,580 --> 07:43:57,580
um old and outdated compute systems
10711
07:43:58,440 --> 07:43:59,440
often referred to as Legacy these May
10712
07:44:01,260 --> 07:44:02,260
well be running applications and you'll
10713
07:44:03,000 --> 07:44:04,000
you could see this a lot if you do a new
10714
07:44:04,620 --> 07:44:05,620
network Consulting you'll go to
10715
07:44:06,600 --> 07:44:07,600
companies that are just running in Old
10716
07:44:08,100 --> 07:44:09,100
software and they want to keep it
10717
07:44:10,138 --> 07:44:11,138
because it still works and it's due to
10718
07:44:12,958 --> 07:44:13,958
the cost and all of the heartache of
10719
07:44:14,458 --> 07:44:15,458
having to upgrade and translate all of
10720
07:44:17,340 --> 07:44:18,340
the data
10721
07:44:19,218 --> 07:44:20,218
these systems can't be taken out of
10722
07:44:21,478 --> 07:44:22,478
service usually but because of the age
10723
07:44:23,520 --> 07:44:24,520
they're more vulnerable to attacks and
10724
07:44:26,340 --> 07:44:27,340
because of the lack of support and the
10725
07:44:28,138 --> 07:44:29,138
support means there's no more security
10726
07:44:29,940 --> 07:44:30,940
patches
10727
07:44:32,458 --> 07:44:33,458
so basically we'll come back into back
10728
07:44:34,798 --> 07:44:35,798
to segmentation and it's important to
10729
07:44:36,900 --> 07:44:37,900
segment these from the rest of the
10730
07:44:38,218 --> 07:44:39,218
network
10731
07:44:40,160 --> 07:44:41,160
service in the network for Public Public
10732
07:44:42,958 --> 07:44:43,958
Access would normally restrict access
10733
07:44:44,940 --> 07:44:45,940
this is classic example is at a public
10734
07:44:48,420 --> 07:44:49,420
library where customers come in and want
10735
07:44:50,878 --> 07:44:51,878
to use the systems but obviously you
10736
07:44:52,860 --> 07:44:53,860
don't want them to have visibility to
10737
07:44:54,600 --> 07:44:55,600
the back end systems where customers
10738
07:44:57,240 --> 07:44:58,240
data is kept and people can get books
10739
07:45:00,180 --> 07:45:01,180
and make payments and all that sort of
10740
07:45:02,100 --> 07:45:03,100
stuff
10741
07:45:03,360 --> 07:45:04,360
so you'd segment the servers and
10742
07:45:05,940 --> 07:45:06,940
resources used by employees on a private
10743
07:45:08,100 --> 07:45:09,100
Network public access to the public
10744
07:45:13,620 --> 07:45:14,620
and net Network segmentations critical
10745
07:45:16,620 --> 07:45:17,620
situations if a private network is
10746
07:45:18,900 --> 07:45:19,900
restricted only to employees it's less
10747
07:45:21,420 --> 07:45:22,420
prone to outside attacks probably
10748
07:45:23,100 --> 07:45:24,100
certainly obvious here in a public
10749
07:45:25,200 --> 07:45:26,200
network even if the server is
10750
07:45:26,878 --> 07:45:27,878
compromised it won't actually affect
10751
07:45:29,040 --> 07:45:30,040
your internal private Network so you
10752
07:45:31,620 --> 07:45:32,620
could do your troubleshooting and
10753
07:45:33,660 --> 07:45:34,660
resolution without worrying about
10754
07:45:36,000 --> 07:45:37,000
um affecting your critical Business
10755
07:45:37,620 --> 07:45:38,620
Systems
10756
07:45:39,420 --> 07:45:40,420
uh testing patches and updates for
10757
07:45:42,000 --> 07:45:43,000
applications should be carried out in a
10758
07:45:43,620 --> 07:45:44,620
test the environment it's often called a
10759
07:45:45,840 --> 07:45:46,840
test bed where you've got a copy of your
10760
07:45:48,360 --> 07:45:49,360
devices
10761
07:45:49,740 --> 07:45:50,740
and you could even be running them
10762
07:45:51,360 --> 07:45:52,360
virtually
10763
07:45:53,218 --> 07:45:54,218
and it's all done in order to prevent or
10764
07:45:56,520 --> 07:45:57,520
foresee problems on your live equipment
10765
07:46:02,820 --> 07:46:03,820
a honey pot is a decoy server set to
10766
07:46:06,138 --> 07:46:07,138
lure attackers studies there and
10767
07:46:09,240 --> 07:46:10,240
methodology and how they break into the
10768
07:46:11,280 --> 07:46:12,280
systems gathers for our zinc forensic
10769
07:46:13,798 --> 07:46:14,798
information and it can be used in the
10770
07:46:16,080 --> 07:46:17,080
event that you actually prosecute
10771
07:46:17,580 --> 07:46:18,580
somebody
10772
07:46:18,958 --> 07:46:19,958
designed to be a little bit more easily
10773
07:46:21,240 --> 07:46:22,240
exploited exploited than the actual
10774
07:46:23,160 --> 07:46:24,160
production server so this would probably
10775
07:46:25,500 --> 07:46:26,500
be the first device discovered by the
10776
07:46:27,240 --> 07:46:28,240
attackers
10777
07:46:28,440 --> 07:46:29,440
has attackers activities logged to get
10778
07:46:30,780 --> 07:46:31,780
insight into their sneaky little methods
10779
07:46:35,458 --> 07:46:36,458
okay an early part is a network segment
10780
07:46:37,920 --> 07:46:38,920
that contains more than one
10781
07:46:40,080 --> 07:46:41,080
um honey pot or only net sorry
10782
07:46:42,958 --> 07:46:43,958
so the honey net would normally look
10783
07:46:45,000 --> 07:46:46,000
like a normal operational Network for
10784
07:46:46,860 --> 07:46:47,860
the attacker
10785
07:46:48,120 --> 07:46:49,120
and it'll make the attacker spend more
10786
07:46:50,820 --> 07:46:51,820
time in the system which gives you more
10787
07:46:52,378 --> 07:46:53,378
time to analyze what they're doing and
10788
07:46:54,660 --> 07:46:55,660
where they're coming from
10789
07:46:57,240 --> 07:46:58,240
all right so we've covered segmentation
10790
07:46:59,360 --> 07:47:00,360
physically logically uses of it and
10791
07:47:03,840 --> 07:47:04,840
critical situations that's the end of
10792
07:47:06,360 --> 07:47:07,360
the presentation thanks for watching
10793
07:47:15,530 --> 07:47:16,530
[Music]
10794
07:47:33,840 --> 07:47:34,840
Network routing and IP addressing IP
10795
07:47:37,798 --> 07:47:38,798
addresses and conversion
10796
07:47:40,440 --> 07:47:41,440
so welcome to this module we're going to
10797
07:47:42,600 --> 07:47:43,600
cover IP addresses and conversions and
10798
07:47:46,500 --> 07:47:47,500
in some of the previous modules we
10799
07:47:48,360 --> 07:47:49,360
talked about a lot of the Technologies
10800
07:47:50,160 --> 07:47:51,160
and theories and protocols that make up
10801
07:47:53,100 --> 07:47:54,100
computer networks and so here we're
10802
07:47:55,020 --> 07:47:56,020
going to discuss some of the more
10803
07:47:56,940 --> 07:47:57,940
important aspects of networking
10804
07:47:59,400 --> 07:48:00,400
specifically the IP address so this
10805
07:48:03,360 --> 07:48:04,360
module is going to begin by introducing
10806
07:48:05,458 --> 07:48:06,458
us to some of the specific protocols
10807
07:48:07,200 --> 07:48:08,200
that are found within the tcpip protocol
10808
07:48:10,740 --> 07:48:11,740
Suite that you need to know about for
10809
07:48:13,320 --> 07:48:14,320
the network plus exam and these are TCP
10810
07:48:16,620 --> 07:48:17,620
and IP and a little more depth we
10811
07:48:18,958 --> 07:48:19,958
mentioned them briefly when we talked
10812
07:48:20,940 --> 07:48:21,940
about the TCP model and then we're going
10813
07:48:24,600 --> 07:48:25,600
to describe UDP which is a connection
10814
07:48:27,320 --> 07:48:28,320
less protocol then we're going to look
10815
07:48:30,900 --> 07:48:31,900
at ARP and rarp two versions that allow
10816
07:48:33,780 --> 07:48:34,780
us to basically or two protocols rather
10817
07:48:37,020 --> 07:48:38,020
that basically allow us to map Mac
10818
07:48:38,820 --> 07:48:39,820
addresses to IP address and which are
10819
07:48:42,058 --> 07:48:43,058
basically responsible for routing in
10820
07:48:44,280 --> 07:48:45,280
general and after that we're going to
10821
07:48:45,840 --> 07:48:46,840
look at two management protocols one
10822
07:48:47,940 --> 07:48:48,940
called icmp which I introduced to you in
10823
07:48:50,700 --> 07:48:51,700
previous modules and I said it was
10824
07:48:52,020 --> 07:48:53,020
related to the Ping a utility we're
10825
07:48:54,660 --> 07:48:55,660
going to learn a little more about that
10826
07:48:55,680 --> 07:48:56,680
and then igmp which is uh slightly
10827
07:49:00,298 --> 07:49:01,298
different has to do more with
10828
07:49:01,558 --> 07:49:02,558
multicasting and unicasting and then
10829
07:49:04,260 --> 07:49:05,260
we're going to continue by outlining uh
10830
07:49:06,600 --> 07:49:07,600
IP packet delivery processes and we're
10831
07:49:10,138 --> 07:49:11,138
going to finish off the module with a
10832
07:49:11,940 --> 07:49:12,940
bit of an introduction into binary and
10833
07:49:15,780 --> 07:49:16,780
decimal conversions so that later on we
10834
07:49:18,898 --> 07:49:19,898
can talk a little more in depth about IP
10835
07:49:20,760 --> 07:49:21,760
addressing and how
10836
07:49:24,260 --> 07:49:25,260
something called subnetting Works which
10837
07:49:27,298 --> 07:49:28,298
is going to require us to understand the
10838
07:49:29,218 --> 07:49:30,218
difference between these two ways of
10839
07:49:30,958 --> 07:49:31,958
writing our numbers and after we have
10840
07:49:34,260 --> 07:49:35,260
covered all these topics we're gonna
10841
07:49:35,520 --> 07:49:36,520
have a fundamental understanding of Ip
10842
07:49:38,100 --> 07:49:39,100
that's going to prepare us for some of
10843
07:49:39,600 --> 07:49:40,600
the more in-depth topics as I just
10844
07:49:41,638 --> 07:49:42,638
mentioned in the following modules
10845
07:49:44,280 --> 07:49:45,280
so let's begin by taking a look at two
10846
07:49:46,620 --> 07:49:47,620
of the most important protocols that
10847
07:49:48,718 --> 07:49:49,718
make up the suite TCP and IP now in
10848
07:49:52,740 --> 07:49:53,740
previous chapters we briefly described
10849
07:49:54,780 --> 07:49:55,780
these two but we still need to take a
10850
07:49:57,298 --> 07:49:58,298
closer look at them to assure that we
10851
07:49:59,520 --> 07:50:00,520
have a complete understanding of the
10852
07:50:02,040 --> 07:50:03,040
many different protocols that are found
10853
07:50:04,080 --> 07:50:05,080
in our protocol Suite so first for those
10854
07:50:07,020 --> 07:50:08,020
applications and instances that depend
10855
07:50:09,478 --> 07:50:10,478
on data to be reliable in terms of
10856
07:50:12,478 --> 07:50:13,478
delivery and integrity the transmission
10857
07:50:15,840 --> 07:50:16,840
control protocol or TCP and I'm just
10858
07:50:20,340 --> 07:50:21,340
going to write out
10859
07:50:23,040 --> 07:50:24,040
transmission
10860
07:50:26,878 --> 07:50:27,878
control
10861
07:50:28,620 --> 07:50:29,620
protocol is a really Dependable protocol
10862
07:50:32,100 --> 07:50:33,100
and provides a number of features first
10863
07:50:35,160 --> 07:50:36,160
it guarantees that data delivery and
10864
07:50:38,520 --> 07:50:39,520
besides
10865
07:50:39,958 --> 07:50:40,958
um guaranteeing that delivery it also
10866
07:50:43,320 --> 07:50:44,320
has a certain amount of reliability it
10867
07:50:46,320 --> 07:50:47,320
also offers flow control which as we've
10868
07:50:48,780 --> 07:50:49,780
mentioned in the past assists ascending
10869
07:50:51,540 --> 07:50:52,540
station in making sure it doesn't send
10870
07:50:53,940 --> 07:50:54,940
data faster then the receiver can handle
10871
07:50:56,820 --> 07:50:57,820
this function also is going to assist in
10872
07:50:59,638 --> 07:51:00,638
the reliability of data because it
10873
07:51:01,978 --> 07:51:02,978
ensures that there isn't any data lost
10874
07:51:04,378 --> 07:51:05,378
due to overloading
10875
07:51:07,320 --> 07:51:08,320
um
10876
07:51:08,280 --> 07:51:09,280
the receiving station
10877
07:51:15,120 --> 07:51:16,120
now TCP also contains something called a
10878
07:51:17,878 --> 07:51:18,878
checksum mechanism and what this does is
10879
07:51:20,280 --> 07:51:21,280
it assists with error detection the
10880
07:51:23,520 --> 07:51:24,520
level of error detection isn't as strong
10881
07:51:25,558 --> 07:51:26,558
as that of some of the lower layers and
10882
07:51:28,080 --> 07:51:29,080
you recall that this is in the transport
10883
07:51:31,378 --> 07:51:32,378
layer of the tcpip stack
10884
07:51:33,840 --> 07:51:34,840
but it does catch some specific errors
10885
07:51:36,478 --> 07:51:37,478
that may go unnoticed by other layers
10886
07:51:39,540 --> 07:51:40,540
and and by the way this checksum
10887
07:51:41,940 --> 07:51:42,940
basically it's it sort of has a number
10888
07:51:44,638 --> 07:51:45,638
that it creates
10889
07:51:46,458 --> 07:51:47,458
based on the data and it can check that
10890
07:51:49,200 --> 07:51:50,200
number at the beginning and at the end
10891
07:51:50,638 --> 07:51:51,638
to make sure we haven't lost anything
10892
07:51:53,520 --> 07:51:54,520
now this protocol attempts to alleviate
10893
07:51:56,780 --> 07:51:57,780
MTU if you recall uh what we talked
10894
07:51:59,760 --> 07:52:00,760
about with MTU there mismatches on the
10895
07:52:02,340 --> 07:52:03,340
data link layer by establishing maximum
10896
07:52:05,340 --> 07:52:06,340
segment sizes that can be accepted by
10897
07:52:07,680 --> 07:52:08,680
TCP this is also going to reduce what we
10898
07:52:10,378 --> 07:52:11,378
talked about earlier that MTU black hole
10899
07:52:13,978 --> 07:52:14,978
now further examining IP or the Internet
10900
07:52:17,160 --> 07:52:18,160
Protocol
10901
07:52:18,840 --> 07:52:19,840
which is aptly name and exists at the
10902
07:52:22,020 --> 07:52:23,020
internet
10903
07:52:23,760 --> 07:52:24,760
layer unlike TCP IP is characterized as
10904
07:52:28,320 --> 07:52:29,320
being connectionless or a best effort
10905
07:52:30,958 --> 07:52:31,958
delivery which is also like UDP which
10906
07:52:32,700 --> 07:52:33,700
we'll see in a second it outlines the
10907
07:52:35,218 --> 07:52:36,218
structure then of information which is
10908
07:52:38,878 --> 07:52:39,878
called datagrams or packets
10909
07:52:43,978 --> 07:52:44,978
and how we're going to package this
10910
07:52:46,378 --> 07:52:47,378
stuff to send it over the network this
10911
07:52:48,958 --> 07:52:49,958
protocol is more concerned with source
10912
07:52:51,180 --> 07:52:52,180
to destination navigation or planning or
10913
07:52:55,080 --> 07:52:56,080
routing as well as host identification
10914
07:52:57,898 --> 07:52:58,898
and data delivery solely by using the IP
10915
07:53:01,740 --> 07:53:02,740
address so this is slightly different
10916
07:53:03,298 --> 07:53:04,298
from TCP which is doing stuff in a much
10917
07:53:06,000 --> 07:53:07,000
more different way now IP is used for
10918
07:53:08,458 --> 07:53:09,458
communications between one or many IP
10919
07:53:11,280 --> 07:53:12,280
based networks and because of its design
10920
07:53:13,978 --> 07:53:14,978
it makes it the principal protocol of
10921
07:53:16,920 --> 07:53:17,920
the internet and it's essential to
10922
07:53:19,798 --> 07:53:20,798
connect to it so unless we are using IP
10923
07:53:23,280 --> 07:53:24,280
address in today's day and age we will
10924
07:53:25,500 --> 07:53:26,500
not be able to connect to this big thing
10925
07:53:27,600 --> 07:53:28,600
called the internet now the terms
10926
07:53:30,478 --> 07:53:31,478
connection less and connection oriented
10927
07:53:34,798 --> 07:53:35,798
relate to the steps that are taken
10928
07:53:37,020 --> 07:53:38,020
before the data is transmitted by a
10929
07:53:39,660 --> 07:53:40,660
given protocol whatever that protocol
10930
07:53:41,100 --> 07:53:42,100
might be with TCP we're looking at
10931
07:53:43,620 --> 07:53:44,620
connection oriented and of course with
10932
07:53:46,320 --> 07:53:47,320
IP we're looking at connection less
10933
07:53:49,320 --> 07:53:50,320
and for instance the connection oriented
10934
07:53:52,260 --> 07:53:53,260
protocol is going to ensure a connection
10935
07:53:55,020 --> 07:53:56,020
is established before the sending of
10936
07:53:57,718 --> 07:53:58,718
data meaning it is oriented towards a
10937
07:54:00,478 --> 07:54:01,478
connection whereas a connection less
10938
07:54:02,520 --> 07:54:03,520
isn't going to doesn't matter if there
10939
07:54:04,740 --> 07:54:05,740
is a connection established already
10940
07:54:06,718 --> 07:54:07,718
so the next protocol which is also
10941
07:54:09,360 --> 07:54:10,360
connection last that we want to talk
10942
07:54:10,860 --> 07:54:11,860
about is something called UDP now since
10943
07:54:14,218 --> 07:54:15,218
we have many applications and their
10944
07:54:16,920 --> 07:54:17,920
functions depend on data being sent in a
10945
07:54:19,620 --> 07:54:20,620
timely manner TCP and its connection
10946
07:54:22,080 --> 07:54:23,080
oriented properties hinder their
10947
07:54:24,478 --> 07:54:25,478
performance in these cases we're able to
10948
07:54:27,058 --> 07:54:28,058
use something called
10949
07:54:28,558 --> 07:54:29,558
UDP again the user
10950
07:54:34,160 --> 07:54:35,160
datagram protocol
10951
07:54:38,760 --> 07:54:39,760
and UDP is connection last just like IP
10952
07:54:42,120 --> 07:54:43,120
is
10953
07:54:44,040 --> 07:54:45,040
and it's a that means it's a best effort
10954
07:54:46,620 --> 07:54:47,620
delivery protocol so with TCP if packets
10955
07:54:49,920 --> 07:54:50,920
get delayed or if they're needed to be
10956
07:54:51,660 --> 07:54:52,660
resent due to a collision the TCP on the
10957
07:54:54,478 --> 07:54:55,478
receiving end is going to wait for the
10958
07:54:56,100 --> 07:54:57,100
lost or late packets to arrive and with
10959
07:54:58,620 --> 07:54:59,620
some sensitive data delivery this is
10960
07:55:01,138 --> 07:55:02,138
going to cause a lot of problems and UDP
10961
07:55:03,620 --> 07:55:04,620
is what we call a stateless protocol
10962
07:55:06,840 --> 07:55:07,840
which prefers the packet loss over the
10963
07:55:10,378 --> 07:55:11,378
delay in waiting so UDP is only going to
10964
07:55:13,620 --> 07:55:14,620
add a checksum to the data for data
10965
07:55:17,218 --> 07:55:18,218
Integrity it's also going to uh address
10966
07:55:21,120 --> 07:55:22,120
port numbers for specific functions
10967
07:55:23,700 --> 07:55:24,700
between the source and the destination
10968
07:55:26,120 --> 07:55:27,120
nodes such as UDP Port 53 for DNS which
10969
07:55:31,080 --> 07:55:32,080
is one that you should remember from an
10970
07:55:32,700 --> 07:55:33,700
earlier module Now udp's features make
10971
07:55:35,878 --> 07:55:36,878
it a solid protocol and it's used for
10972
07:55:38,940 --> 07:55:39,940
applications such as VoIP or voice over
10973
07:55:41,820 --> 07:55:42,820
IP
10974
07:55:43,080 --> 07:55:44,080
and online gaming this makes sense
10975
07:55:45,958 --> 07:55:46,958
because we don't care if every single
10976
07:55:49,200 --> 07:55:50,200
little packet arrives what we want is we
10977
07:55:51,180 --> 07:55:52,180
want the speed with which
10978
07:55:54,120 --> 07:55:55,120
UDP is going to deliver stuff obviously
10979
07:55:56,458 --> 07:55:57,458
if we miss a couple packets in voice
10980
07:55:58,020 --> 07:55:59,020
that's okay they drop but we don't want
10981
07:56:01,080 --> 07:56:02,080
to have to wait until the next packet
10982
07:56:03,360 --> 07:56:04,360
arrives that's going to actually cause
10983
07:56:04,680 --> 07:56:05,680
much more of a delay and so we're going
10984
07:56:06,660 --> 07:56:07,660
to use this one in more VoIP and online
10985
07:56:09,240 --> 07:56:10,240
gaming purposes now the next protocol we
10986
07:56:12,600 --> 07:56:13,600
want to be familiar with
10987
07:56:14,458 --> 07:56:15,458
is called ARP and it's also necessary
10988
07:56:16,740 --> 07:56:17,740
for routing ARP or the address
10989
07:56:21,660 --> 07:56:22,660
resolution
10990
07:56:25,200 --> 07:56:26,200
protocol and
10991
07:56:27,840 --> 07:56:28,840
the reverse
10992
07:56:29,638 --> 07:56:30,638
address resolution protocol our request
10993
07:56:33,898 --> 07:56:34,898
and reply protocols that are used to map
10994
07:56:36,780 --> 07:56:37,780
one kind of address to another
10995
07:56:39,138 --> 07:56:40,138
specifically ARP is designed to map IP
10996
07:56:42,718 --> 07:56:43,718
addresses you need addresses that are
10997
07:56:45,120 --> 07:56:46,120
necessary to tcpip communication to Mac
10998
07:56:49,500 --> 07:56:50,500
addresses which are also known as we've
10999
07:56:52,020 --> 07:56:53,020
discussed in the past as physical
11000
07:56:54,780 --> 07:56:55,780
addresses
11001
07:56:59,520 --> 07:57:00,520
and again IP addresses
11002
07:57:02,100 --> 07:57:03,100
work on the networking layer
11003
07:57:08,040 --> 07:57:09,040
or in tcpi PV internet layer
11004
07:57:14,520 --> 07:57:15,520
whereas Mac addresses operate on the
11005
07:57:17,760 --> 07:57:18,760
network interface layer of TCP which in
11006
07:57:21,298 --> 07:57:22,298
OSI would be the data link layer
11007
07:57:24,898 --> 07:57:25,898
layer 2.
11008
07:57:27,718 --> 07:57:28,718
now in tcpipnetworking
11009
07:57:31,020 --> 07:57:32,020
ARP operates at the lowest layer the
11010
07:57:34,680 --> 07:57:35,680
network interface layer in total whereas
11011
07:57:37,978 --> 07:57:38,978
in the OSI model we say that it actually
11012
07:57:40,378 --> 07:57:41,378
operates between
11013
07:57:43,020 --> 07:57:44,020
the data link layer
11014
07:57:45,660 --> 07:57:46,660
and the physical layer
11015
07:57:50,340 --> 07:57:51,340
and this is because it wasn't designed
11016
07:57:52,320 --> 07:57:53,320
specifically for the OSI model it was
11017
07:57:55,200 --> 07:57:56,200
designed for the tcpip model now ARP and
11018
07:57:58,860 --> 07:57:59,860
rarp play very important roles in the
11019
07:58:01,378 --> 07:58:02,378
way networks operate the computer wants
11020
07:58:04,080 --> 07:58:05,080
to communicate with any other computer
11021
07:58:06,000 --> 07:58:07,000
within the local area network the MAC
11022
07:58:08,520 --> 07:58:09,520
address is the identifier that's used
11023
07:58:10,620 --> 07:58:11,620
and if that device wishes to communicate
11024
07:58:12,898 --> 07:58:13,898
outside of the local area network the
11025
07:58:15,478 --> 07:58:16,478
destination Mac address is going to be
11026
07:58:17,638 --> 07:58:18,638
that of the router so the our process
11027
07:58:20,820 --> 07:58:21,820
works by first
11028
07:58:23,298 --> 07:58:24,298
receiving the IP address from IP or the
11029
07:58:29,160 --> 07:58:30,160
Internet Protocol
11030
07:58:30,360 --> 07:58:31,360
then ARP has the MAC address in its
11031
07:58:34,260 --> 07:58:35,260
cached table so the router has what are
11032
07:58:37,260 --> 07:58:38,260
called ARP tables
11033
07:58:38,940 --> 07:58:39,940
that link IP addresses to Mac addresses
11034
07:58:42,478 --> 07:58:43,478
we call this the ARP table
11035
07:58:45,540 --> 07:58:46,540
so it looks in there to see if it no if
11036
07:58:48,180 --> 07:58:49,180
it has a MAC address for the IP address
11037
07:58:50,340 --> 07:58:51,340
listed
11038
07:58:52,260 --> 07:58:53,260
it then sends it back to the IP if it if
11039
07:58:57,240 --> 07:58:58,240
it does have it and if it doesn't have
11040
07:59:00,120 --> 07:59:01,120
it it broadcasts the message it's sent
11041
07:59:03,360 --> 07:59:04,360
in order to resolve what we call resolve
11042
07:59:06,958 --> 07:59:07,958
the address
11043
07:59:08,520 --> 07:59:09,520
to a MAC address
11044
07:59:10,620 --> 07:59:11,620
and the target computer with the IP
11045
07:59:12,718 --> 07:59:13,718
address responds to that broadcast
11046
07:59:15,420 --> 07:59:16,420
message with what's called a unicast
11047
07:59:18,298 --> 07:59:19,298
message and we've discussed that that
11048
07:59:20,218 --> 07:59:21,218
contains the MAC address that it's
11049
07:59:22,020 --> 07:59:23,020
seeking
11050
07:59:23,040 --> 07:59:24,040
ARP then will add the MAC address to its
11051
07:59:26,520 --> 07:59:27,520
table so the next time we don't have to
11052
07:59:28,680 --> 07:59:29,680
go through this whole process
11053
07:59:32,218 --> 07:59:33,218
and then it Returns the IP address to
11054
07:59:36,360 --> 07:59:37,360
the requesting device as it would have
11055
07:59:39,240 --> 07:59:40,240
if it just had it
11056
07:59:41,160 --> 07:59:42,160
now RP is used to do the opposite that
11057
07:59:45,840 --> 07:59:46,840
is to map Mac addresses of a given
11058
07:59:48,240 --> 07:59:49,240
system to their assigned IP addresses
11059
07:59:50,580 --> 07:59:51,580
and it sort of works in Reverse from all
11060
07:59:52,740 --> 07:59:53,740
this now that's a very general overview
11061
07:59:55,080 --> 07:59:56,080
of ARP and rarp and if you were to go
11062
07:59:56,820 --> 07:59:57,820
into Cisco certifications for instance
11063
07:59:58,680 --> 07:59:59,680
you go a little more in depth into this
11064
08:00:00,840 --> 08:00:01,840
but for Network plus this is really
11065
08:00:02,458 --> 08:00:03,458
where we need to stop with this protocol
11066
08:00:04,740 --> 08:00:05,740
so the next protocol I want to talk
11067
08:00:06,540 --> 08:00:07,540
about is icmp which is also called the
11068
08:00:11,580 --> 08:00:12,580
internet
11069
08:00:17,160 --> 08:00:18,160
control
11070
08:00:21,058 --> 08:00:22,058
message protocol
11071
08:00:23,580 --> 08:00:24,580
it's a protocol designed to send
11072
08:00:26,218 --> 08:00:27,218
messages that relate to the status of a
11073
08:00:28,680 --> 08:00:29,680
system it's not meant to actually send
11074
08:00:31,020 --> 08:00:32,020
data so icmp messages are used generally
11075
08:00:35,340 --> 08:00:36,340
speaking for Diagnostic and testing
11076
08:00:37,500 --> 08:00:38,500
purposes and they can also be used as a
11077
08:00:39,958 --> 08:00:40,958
response to errors that occur in the
11078
08:00:42,478 --> 08:00:43,478
normal operations of Ip and if you
11079
08:00:44,760 --> 08:00:45,760
recall one of the times that we talked
11080
08:00:46,620 --> 08:00:47,620
about that was for instance with the MTU
11081
08:00:50,100 --> 08:00:51,100
black hole
11082
08:00:51,660 --> 08:00:52,660
when that icmp message couldn't get back
11083
08:00:55,020 --> 08:00:56,020
to the original router now many Internet
11084
08:00:58,500 --> 08:00:59,500
Protocol utilities are actually derived
11085
08:01:01,020 --> 08:01:02,020
from icmp messages such as Tracer or
11086
08:01:05,280 --> 08:01:06,280
trace route
11087
08:01:06,420 --> 08:01:07,420
path ping and ping and we'll talk about
11088
08:01:09,540 --> 08:01:10,540
these in a little more depth than if you
11089
08:01:11,218 --> 08:01:12,218
were around for uh a plus we definitely
11090
08:01:13,920 --> 08:01:14,920
talked about these two quite a bit icmp
11091
08:01:17,340 --> 08:01:18,340
is actually one of the core Protocols of
11092
08:01:19,860 --> 08:01:20,860
the IP suite and it operates at the
11093
08:01:22,860 --> 08:01:23,860
internet layer which as you recall is
11094
08:01:25,520 --> 08:01:26,520
tcpip
11095
08:01:27,860 --> 08:01:28,860
second layer
11096
08:01:30,478 --> 08:01:31,478
now icmp is a control protocol used by
11097
08:01:34,440 --> 08:01:35,440
networked computers and operating
11098
08:01:36,478 --> 08:01:37,478
systems and the most common utility that
11099
08:01:39,718 --> 08:01:40,718
we're going to see is what's called
11100
08:01:42,298 --> 08:01:43,298
ping which we've talked about which uses
11101
08:01:44,700 --> 08:01:45,700
what are called icmp Echo requests and
11102
08:01:48,120 --> 08:01:49,120
they reply to determine connection
11103
08:01:50,280 --> 08:01:51,280
statuses of a Target system so I could
11104
08:01:53,638 --> 08:01:54,638
ping a specific system to see if it's on
11105
08:01:56,340 --> 08:01:57,340
the network of course there are some
11106
08:01:58,138 --> 08:01:59,138
reasons why the icmp as we've talked
11107
08:02:00,180 --> 08:02:01,180
about might not make it back to me or
11108
08:02:02,280 --> 08:02:03,280
it's configured not to respond perhaps
11109
08:02:04,378 --> 08:02:05,378
through a firewall finally we need to
11110
08:02:06,718 --> 08:02:07,718
talk about igmp or the internet
11111
08:02:14,520 --> 08:02:15,520
group
11112
08:02:17,340 --> 08:02:18,340
management protocol
11113
08:02:20,700 --> 08:02:21,700
it should not be confused with icmp it's
11114
08:02:23,700 --> 08:02:24,700
slightly different
11115
08:02:25,020 --> 08:02:26,020
it is used to establish memberships for
11116
08:02:28,620 --> 08:02:29,620
multicast groups now multicasting is
11117
08:02:31,620 --> 08:02:32,620
where a computer wishes to send data to
11118
08:02:34,080 --> 08:02:35,080
a lot of other computers through the
11119
08:02:36,420 --> 08:02:37,420
internet by identifying which computers
11120
08:02:38,700 --> 08:02:39,700
have subscribed or which ones wish to
11121
08:02:41,878 --> 08:02:42,878
receive the data we looked at this
11122
08:02:44,160 --> 08:02:45,160
earlier and determined that routers
11123
08:02:45,840 --> 08:02:46,840
determine a multicast group now in a
11124
08:02:48,958 --> 08:02:49,958
host implementation a host is going to
11125
08:02:52,080 --> 08:02:53,080
make a request for
11126
08:02:54,840 --> 08:02:55,840
and igmp implemented router to join the
11127
08:02:59,100 --> 08:03:00,100
membership of a multicast group
11128
08:03:02,398 --> 08:03:03,398
certain applications such as those for
11129
08:03:05,280 --> 08:03:06,280
online gaming can use igmp for what are
11130
08:03:09,000 --> 08:03:10,000
called
11131
08:03:09,920 --> 08:03:10,920
one-to-many Communications the one being
11132
08:03:13,558 --> 08:03:14,558
the game server and the many being all
11133
08:03:16,500 --> 08:03:17,500
of those end users that have subscribed
11134
08:03:19,080 --> 08:03:20,080
to the gaming session
11135
08:03:21,058 --> 08:03:22,058
so those routers with igmp
11136
08:03:23,458 --> 08:03:24,458
implementation periodically will send
11137
08:03:26,100 --> 08:03:27,100
out queries to determine the multicast
11138
08:03:28,860 --> 08:03:29,860
membership of those devices within range
11139
08:03:32,820 --> 08:03:33,820
and then those hosts that have
11140
08:03:34,558 --> 08:03:35,558
membership are going to respond to the
11141
08:03:36,360 --> 08:03:37,360
queries with a membership
11142
08:03:39,120 --> 08:03:40,120
report
11143
08:03:42,120 --> 08:03:43,120
now the process of delivering an IP
11144
08:03:45,780 --> 08:03:46,780
packet is simple
11145
08:03:47,638 --> 08:03:48,638
it begins with resolving the name of the
11146
08:03:50,820 --> 08:03:51,820
host to its assigned IP address like we
11147
08:03:54,540 --> 08:03:55,540
talked about with arp and the connection
11148
08:03:56,878 --> 08:03:57,878
is established by a service at if you
11149
08:04:00,058 --> 08:04:01,058
recall the transport layer
11150
08:04:03,180 --> 08:04:04,180
now after the name resolution and
11151
08:04:05,638 --> 08:04:06,638
connection establishment the IP address
11152
08:04:08,520 --> 08:04:09,520
is then sent down to the internet layer
11153
08:04:12,240 --> 08:04:13,240
and the next step is where the IP looks
11154
08:04:15,120 --> 08:04:16,120
at the subnet mask which we've talked
11155
08:04:17,458 --> 08:04:18,458
about in a plus and we'll talk about
11156
08:04:18,660 --> 08:04:19,660
more of the IP address to determine
11157
08:04:21,840 --> 08:04:22,840
whether the destination is local to the
11158
08:04:25,260 --> 08:04:26,260
computer on what we say is the same
11159
08:04:27,718 --> 08:04:28,718
subnet or whether it's remote or on
11160
08:04:31,978 --> 08:04:32,978
another Network after this determination
11161
08:04:34,978 --> 08:04:35,978
is made then finally the packet is
11162
08:04:38,100 --> 08:04:39,100
routed and delivered
11163
08:04:40,620 --> 08:04:41,620
okay so we now understand TCP a little
11164
08:04:44,760 --> 08:04:45,760
more fully some of the protocols that
11165
08:04:47,280 --> 08:04:48,280
are dealt with in great detail and how
11166
08:04:51,840 --> 08:04:52,840
IP packet delivery works so let's talk
11167
08:04:54,540 --> 08:04:55,540
about binary and decimal which are going
11168
08:04:57,000 --> 08:04:58,000
to be really important when we get into
11169
08:04:59,040 --> 08:05:00,040
what's called subnetting and it's just
11170
08:05:01,378 --> 08:05:02,378
good to know as an I.T professional
11171
08:05:03,180 --> 08:05:04,180
anyway
11172
08:05:04,320 --> 08:05:05,320
specifically
11173
08:05:06,260 --> 08:05:07,260
understanding binary or how to convert
11174
08:05:09,200 --> 08:05:10,200
binary which is the number of computers
11175
08:05:11,820 --> 08:05:12,820
the way computers talk to decimal which
11176
08:05:14,040 --> 08:05:15,040
is the way that we deal with numbers and
11177
08:05:16,320 --> 08:05:17,320
decimal to binary
11178
08:05:19,080 --> 08:05:20,080
pertains to a lot of different aspects
11179
08:05:21,600 --> 08:05:22,600
of as I just mentioned networking so to
11180
08:05:24,840 --> 08:05:25,840
begin with binary is the name implies
11181
08:05:27,240 --> 08:05:28,240
from buy is what we call a base 2 system
11182
08:05:31,138 --> 08:05:32,138
more commonly we used a base 10 system
11183
08:05:33,958 --> 08:05:34,958
decimal
11184
08:05:35,878 --> 08:05:36,878
now this means that we have 10
11185
08:05:39,120 --> 08:05:40,120
possibilities for every place value we
11186
08:05:43,320 --> 08:05:44,320
have between a zero and nine you add
11187
08:05:45,058 --> 08:05:46,058
that up there are 10.
11188
08:05:46,620 --> 08:05:47,620
now with binary there's only two options
11189
08:05:49,138 --> 08:05:50,138
either zero or one
11190
08:05:53,580 --> 08:05:54,580
so we can either have a single zero or a
11191
08:05:56,638 --> 08:05:57,638
single one and that's what we call a DOT
11192
08:05:59,160 --> 08:06:00,160
a binary digit or
11193
08:06:02,398 --> 08:06:03,398
a bit
11194
08:06:05,700 --> 08:06:06,700
so the binary number has Place markers
11195
08:06:09,718 --> 08:06:10,718
that are similar to the base 10 system
11196
08:06:13,020 --> 08:06:14,020
for instance if we have a a decimal base
11197
08:06:17,280 --> 08:06:18,280
10 numbering system the second place
11198
08:06:19,920 --> 08:06:20,920
Mark designates the tens if we imagine
11199
08:06:23,100 --> 08:06:24,100
that there's a
11200
08:06:25,020 --> 08:06:26,020
uh period or a decimal right there
11201
08:06:28,920 --> 08:06:29,920
the third designates the hundreds and
11202
08:06:31,260 --> 08:06:32,260
then we move to thousandths and ten
11203
08:06:34,440 --> 08:06:35,440
thousandths and hundred thousandths and
11204
08:06:36,600 --> 08:06:37,600
so on and so forth and in each one of
11205
08:06:39,000 --> 08:06:40,000
these we can have anywhere from zero
11206
08:06:42,660 --> 08:06:43,660
to 9 and that's ten options in each one
11207
08:06:46,020 --> 08:06:47,020
of those spots
11208
08:06:47,700 --> 08:06:48,700
now in base 2 numbering system which is
11209
08:06:52,138 --> 08:06:53,138
binary we have only two options a one or
11210
08:06:55,920 --> 08:06:56,920
a zero in either one of those places and
11211
08:06:57,898 --> 08:06:58,898
in computers especially in a lot of Ip
11212
08:07:00,958 --> 08:07:01,958
addressing we really deal with the
11213
08:07:03,958 --> 08:07:04,958
difference between uh eight different
11214
08:07:08,638 --> 08:07:09,638
places
11215
08:07:10,200 --> 08:07:11,200
so we're going to call these eight and
11216
08:07:13,440 --> 08:07:14,440
octet
11217
08:07:14,638 --> 08:07:15,638
so this eight Place binary digit is
11218
08:07:16,798 --> 08:07:17,798
referred to as an octet because there's
11219
08:07:18,240 --> 08:07:19,240
one two three four five six seven eight
11220
08:07:22,138 --> 08:07:23,138
of them and you'll see these numbers pop
11221
08:07:24,000 --> 08:07:25,000
up over and over again so this is really
11222
08:07:26,580 --> 08:07:27,580
as far as you need to know for binary
11223
08:07:28,200 --> 08:07:29,200
although you can go even further so if
11224
08:07:30,240 --> 08:07:31,240
we look at this octet from the right
11225
08:07:32,878 --> 08:07:33,878
side to the left
11226
08:07:34,378 --> 08:07:35,378
the first place Mark is what we call
11227
08:07:38,760 --> 08:07:39,760
2 to the 0 power
11228
08:07:40,620 --> 08:07:41,620
right if we were talking about this in
11229
08:07:43,200 --> 08:07:44,200
tens this would be the ones place y
11230
08:07:46,500 --> 08:07:47,500
because it's 10 to the zero power which
11231
08:07:48,540 --> 08:07:49,540
is ones anything taken to the zero power
11232
08:07:51,058 --> 08:07:52,058
is one
11233
08:07:52,978 --> 08:07:53,978
next we have 10 to the first Power which
11234
08:07:56,040 --> 08:07:57,040
is going to equal 2. if you recall we
11235
08:07:57,840 --> 08:07:58,840
call this the tens place 10 to the one
11236
08:08:00,058 --> 08:08:01,058
power means 10 by itself is 10.
11237
08:08:05,100 --> 08:08:06,100
then we have 10 to the second power
11238
08:08:06,898 --> 08:08:07,898
which is 4 and if you recall in decimal
11239
08:08:10,378 --> 08:08:11,378
this is 10 to the second which would be
11240
08:08:12,478 --> 08:08:13,478
10 times 10 which is 100 you can see
11241
08:08:14,398 --> 08:08:15,398
where this is going
11242
08:08:16,200 --> 08:08:17,200
so 2 to the third is eight two to the
11243
08:08:19,320 --> 08:08:20,320
fourth equals 16 2 to the fifth equals
11244
08:08:22,320 --> 08:08:23,320
32 2 to the 6 equals 64 and 2 to the 7
11245
08:08:26,340 --> 08:08:27,340
equals 128. so each one of these Place
11246
08:08:29,878 --> 08:08:30,878
markers is equivalent
11247
08:08:33,958 --> 08:08:34,958
to this number whether it's turned on or
11248
08:08:37,200 --> 08:08:38,200
off
11249
08:08:40,740 --> 08:08:41,740
now to help clarify this a bit each
11250
08:08:43,740 --> 08:08:44,740
place here
11251
08:08:45,000 --> 08:08:46,000
has one of two options correct because
11252
08:08:47,638 --> 08:08:48,638
it's base two if it's off that means
11253
08:08:51,058 --> 08:08:52,058
it's a zero as you see right here and
11254
08:08:53,700 --> 08:08:54,700
the numbered means it's not being
11255
08:08:55,320 --> 08:08:56,320
counted so we don't count any of these
11256
08:08:57,420 --> 08:08:58,420
numbers we've just calculated so if all
11257
08:08:59,700 --> 08:09:00,700
the bits are off that means that we have
11258
08:09:01,558 --> 08:09:02,558
a number of zero
11259
08:09:03,240 --> 08:09:04,240
if all of the bits are on then this
11260
08:09:06,120 --> 08:09:07,120
means we add each of the numbers
11261
08:09:08,040 --> 08:09:09,040
together
11262
08:09:10,260 --> 08:09:11,260
so we get 128 plus 64 plus 32 plus 16
11263
08:09:15,000 --> 08:09:16,000
plus 8 plus 4 plus 2 plus 1 which equals
11264
08:09:18,740 --> 08:09:19,740
255. now believe it or not you can
11265
08:09:21,240 --> 08:09:22,240
create any combination of numbers from
11266
08:09:24,360 --> 08:09:25,360
just binary you don't need decimal we're
11267
08:09:27,420 --> 08:09:28,420
going to see that in just a second
11268
08:09:29,100 --> 08:09:30,100
so for example
11269
08:09:30,958 --> 08:09:31,958
let's say the binary number is uh
11270
08:09:37,040 --> 08:09:38,040
zero zero zero zero zero one one one
11271
08:09:41,898 --> 08:09:42,898
well in this case the 128 64 32 16 and 8
11272
08:09:47,940 --> 08:09:48,940
Bits are all off the only ones that are
11273
08:09:50,820 --> 08:09:51,820
on are four two and one and if we add
11274
08:09:54,180 --> 08:09:55,180
those together four plus two plus one
11275
08:09:57,540 --> 08:09:58,540
we'll get 7.
11276
08:10:00,540 --> 08:10:01,540
4 plus 2 is 6 plus 1 is 7.
11277
08:10:04,440 --> 08:10:05,440
if we take another number
11278
08:10:07,920 --> 08:10:08,920
say 0 1 1 0 0 1 1 0.
11279
08:10:12,840 --> 08:10:13,840
then this is going to equate to 102. why
11280
08:10:16,798 --> 08:10:17,798
64 plus 32 equals 96 plus 4 equals 100
11281
08:10:24,420 --> 08:10:25,420
plus 2 equals 102.
11282
08:10:28,080 --> 08:10:29,080
so it's pretty simple you just take the
11283
08:10:30,540 --> 08:10:31,540
number with the ones under it and add
11284
08:10:31,978 --> 08:10:32,978
them together so now that we've
11285
08:10:33,478 --> 08:10:34,478
converted binary into decimal a number
11286
08:10:37,260 --> 08:10:38,260
that we all know let's go ahead and see
11287
08:10:39,898 --> 08:10:40,898
if we can convert the other way decimal
11288
08:10:41,580 --> 08:10:42,580
to Binary now for this process we're
11289
08:10:43,680 --> 08:10:44,680
going to use the same exact chart
11290
08:10:45,660 --> 08:10:46,660
that we just saw
11291
08:10:47,458 --> 08:10:48,458
with the binary conversion
11292
08:10:49,740 --> 08:10:50,740
and this chart is going to help us
11293
08:10:51,420 --> 08:10:52,420
visually represent all the binary digits
11294
08:10:54,058 --> 08:10:55,058
which is why I like it in their
11295
08:10:55,378 --> 08:10:56,378
placeholders and it makes it a lot
11296
08:10:57,058 --> 08:10:58,058
easier so for decimal to Binary we
11297
08:10:59,340 --> 08:11:00,340
simply go from left to right and break
11298
08:11:01,378 --> 08:11:02,378
down the number until we reach the zero
11299
08:11:04,978 --> 08:11:05,978
so let me break that down a little bit
11300
08:11:07,200 --> 08:11:08,200
for instance if we take the number 128
11301
08:11:10,558 --> 08:11:11,558
right this is pretty easy to convert we
11302
08:11:12,898 --> 08:11:13,898
plug it into this chart how many times
11303
08:11:14,760 --> 08:11:15,760
does 128 go into 128
11304
08:11:18,058 --> 08:11:19,058
one time
11305
08:11:19,620 --> 08:11:20,620
if we take all the others and we
11306
08:11:22,138 --> 08:11:23,138
subtract them we're going to have zero
11307
08:11:23,580 --> 08:11:24,580
right because now 128 minus 128 is zero
11308
08:11:26,580 --> 08:11:27,580
that leaves us with our binary number
11309
08:11:30,000 --> 08:11:31,000
one zero zero zero zero zero zero zero
11310
08:11:33,718 --> 08:11:34,718
which is equivalent to 128.
11311
08:11:36,780 --> 08:11:37,780
now if we take a look at a different
11312
08:11:38,638 --> 08:11:39,638
number let's say the number 218
11313
08:11:43,378 --> 08:11:44,378
this is going to take a little more math
11314
08:11:46,500 --> 08:11:47,500
does 218 go in does 128 go into 218 it
11315
08:11:49,680 --> 08:11:50,680
certainly does
11316
08:11:51,240 --> 08:11:52,240
so 218 minus 128 has a remainder
11317
08:11:55,500 --> 08:11:56,500
of a certain amount which is 90.
11318
08:11:59,160 --> 08:12:00,160
does 64 go into 90 it does we now have a
11319
08:12:02,520 --> 08:12:03,520
remainder of 26. does 32 go into 26 no
11320
08:12:07,020 --> 08:12:08,020
it doesn't so we put a zero
11321
08:12:09,540 --> 08:12:10,540
does 16 go into 26 yep it does which
11322
08:12:12,898 --> 08:12:13,898
leaves us with a remainder of 10.
11323
08:12:15,360 --> 08:12:16,360
does 8 go into 10 it does which leaves
11324
08:12:18,298 --> 08:12:19,298
us a remainder of 2 does 4 go into 2 it
11325
08:12:21,240 --> 08:12:22,240
does not so that leaves us with zero we
11326
08:12:23,878 --> 08:12:24,878
still have our two does two go into 2
11327
08:12:25,920 --> 08:12:26,920
yep and then do we have anything left
11328
08:12:27,718 --> 08:12:28,718
over nope we're at zero now so we have
11329
08:12:30,240 --> 08:12:31,240
zero if we now add all those up this is
11330
08:12:32,940 --> 08:12:33,940
our binary number one one zero one one
11331
08:12:36,000 --> 08:12:37,000
zero one zero now while this might seem
11332
08:12:39,660 --> 08:12:40,660
like a fairly long process it's
11333
08:12:42,298 --> 08:12:43,298
important to understand how this works
11334
08:12:44,520 --> 08:12:45,520
because when we get into subnetting it's
11335
08:12:47,160 --> 08:12:48,160
really going to become important so we
11336
08:12:49,378 --> 08:12:50,378
can have a better understanding of
11337
08:12:50,820 --> 08:12:51,820
networking in general
11338
08:12:54,000 --> 08:12:55,000
so just to recap everything we've talked
11339
08:12:56,458 --> 08:12:57,458
about we described these protocols in
11340
08:12:58,798 --> 08:12:59,798
the tcpip suite first TCP transmission
11341
08:13:02,218 --> 08:13:03,218
control and IP Internet Protocol one is
11342
08:13:05,458 --> 08:13:06,458
connection oriented
11343
08:13:10,558 --> 08:13:11,558
and the other is
11344
08:13:15,058 --> 08:13:16,058
connection less
11345
08:13:16,798 --> 08:13:17,798
meaning that it just is worried about
11346
08:13:18,298 --> 08:13:19,298
delivery remember IP is what is
11347
08:13:20,820 --> 08:13:21,820
responsible for that IP addressing
11348
08:13:25,378 --> 08:13:26,378
UDP is also connection less
11349
08:13:28,020 --> 08:13:29,020
similar in some ways to TCP but it's not
11350
08:13:31,978 --> 08:13:32,978
connection oriented
11351
08:13:34,200 --> 08:13:35,200
then we had ARP and reverse ARP address
11352
08:13:36,780 --> 08:13:37,780
resolution protocol which job is to map
11353
08:13:40,138 --> 08:13:41,138
IP addresses
11354
08:13:43,020 --> 08:13:44,020
to Mac addresses
11355
08:13:44,760 --> 08:13:45,760
we talked about icmp which is what we
11356
08:13:47,820 --> 08:13:48,820
use
11357
08:13:48,718 --> 08:13:49,718
when we're dealing with the status of a
11358
08:13:50,878 --> 08:13:51,878
system
11359
08:13:52,500 --> 08:13:53,500
internet control message protocol
11360
08:13:55,860 --> 08:13:56,860
and then we talk about igmp the internet
11361
08:13:59,458 --> 08:14:00,458
group management protocol which is more
11362
08:14:03,240 --> 08:14:04,240
dealing with multicast groups
11363
08:14:06,840 --> 08:14:07,840
we then talked very briefly about the IP
11364
08:14:09,240 --> 08:14:10,240
packet delivery process which was pretty
11365
08:14:11,280 --> 08:14:12,280
simple right it's packaged it's sent we
11366
08:14:15,420 --> 08:14:16,420
determine where it needs to go once it's
11367
08:14:17,878 --> 08:14:18,878
determined where it needs to go it's
11368
08:14:19,620 --> 08:14:20,620
sent there
11369
08:14:20,760 --> 08:14:21,760
finally we explained the binary
11370
08:14:23,340 --> 08:14:24,340
conversion which is going to be really
11371
08:14:25,320 --> 08:14:26,320
important for IP addressing including
11372
08:14:27,660 --> 08:14:28,660
how to go from binary
11373
08:14:29,700 --> 08:14:30,700
which is a base 2 system
11374
08:14:34,920 --> 08:14:35,920
to decimal
11375
08:14:38,458 --> 08:14:39,458
which is a base 10 system
11376
08:14:41,820 --> 08:14:42,820
and Back Again
11377
08:14:47,030 --> 08:14:48,030
[Music]
11378
08:15:08,820 --> 08:15:09,820
Network routing and IP addressing IP
11379
08:15:12,120 --> 08:15:13,120
addresses and subnetting
11380
08:15:14,940 --> 08:15:15,940
so having discussed IP addressing and
11381
08:15:17,458 --> 08:15:18,458
routing in general we're now going to
11382
08:15:19,920 --> 08:15:20,920
further examine IP addressing and the
11383
08:15:22,798 --> 08:15:23,798
methods of logically not physically
11384
08:15:25,138 --> 08:15:26,138
dividing up our networks this way we can
11385
08:15:28,378 --> 08:15:29,378
keep not only better track of all the
11386
08:15:30,660 --> 08:15:31,660
devices on the network but also organize
11387
08:15:32,760 --> 08:15:33,760
them for security performance and other
11388
08:15:36,000 --> 08:15:37,000
reasons after we complete this module
11389
08:15:38,520 --> 08:15:39,520
we're going to have a better
11390
08:15:39,298 --> 08:15:40,298
understanding of how our network devices
11391
08:15:41,700 --> 08:15:42,700
are identified both by other devices and
11392
08:15:45,898 --> 08:15:46,898
by individuals such as ourselves since
11393
08:15:48,240 --> 08:15:49,240
we're not computers
11394
08:15:49,680 --> 08:15:50,680
so first we're going to identify what a
11395
08:15:53,160 --> 08:15:54,160
network address is versus a network name
11396
08:15:56,340 --> 08:15:57,340
one the network address is for other
11397
08:15:58,920 --> 08:15:59,920
devices a network name is really for us
11398
08:16:01,920 --> 08:16:02,920
since it would be difficult for us to
11399
08:16:03,540 --> 08:16:04,540
remember all these numbers much like
11400
08:16:05,760 --> 08:16:06,760
using a phone number and a cell phone
11401
08:16:08,638 --> 08:16:09,638
next we're going to describe the ipv4
11402
08:16:12,378 --> 08:16:13,378
addressing scheme and ipv4 is important
11403
08:16:16,798 --> 08:16:17,798
to know because even though we have a
11404
08:16:19,500 --> 08:16:20,500
newer version IPv6 ipv4 is still
11405
08:16:22,500 --> 08:16:23,500
deployed in most situations and it's
11406
08:16:25,080 --> 08:16:26,080
covered to the most extent on network
11407
08:16:27,000 --> 08:16:28,000
plus when we get to IPv6 which is
11408
08:16:29,458 --> 08:16:30,458
different version six there are a lot of
11409
08:16:31,680 --> 08:16:32,680
benefits then we'll describe it later
11410
08:16:33,180 --> 08:16:34,180
but really understanding ipv4 is really
11411
08:16:36,540 --> 08:16:37,540
important after we take a look at that
11412
08:16:38,398 --> 08:16:39,398
we're going to look at subnetting and a
11413
08:16:40,740 --> 08:16:41,740
subnet mask you might have seen this and
11414
08:16:43,860 --> 08:16:44,860
these are the numbers and we've probably
11415
08:16:46,080 --> 08:16:47,080
mentioned to them in the past such as
11416
08:16:50,420 --> 08:16:51,420
255.255.0.0 and so on and so forth and
11417
08:16:53,160 --> 08:16:54,160
we're going to describe how this allows
11418
08:16:54,958 --> 08:16:55,958
us to separate out the network ID from
11419
08:16:57,958 --> 08:16:58,958
the node ID or the device's ID or
11420
08:17:00,780 --> 08:17:01,780
address from the networks address much
11421
08:17:03,898 --> 08:17:04,898
like our ZIP code versus our street
11422
08:17:06,120 --> 08:17:07,120
address after that we're gonna just
11423
08:17:08,580 --> 08:17:09,580
describe the rules of subnet masks and
11424
08:17:11,638 --> 08:17:12,638
their IP addresses and knowing binary is
11425
08:17:14,458 --> 08:17:15,458
really going to help us understand all
11426
08:17:16,620 --> 08:17:17,620
of this stuff
11427
08:17:18,000 --> 08:17:19,000
after that we're going to apply a subnet
11428
08:17:21,600 --> 08:17:22,600
mask to an IP address using something
11429
08:17:23,940 --> 08:17:24,940
called anding which again gets back to
11430
08:17:26,638 --> 08:17:27,638
Binary and might even remind you of
11431
08:17:28,740 --> 08:17:29,740
something you learned in high school
11432
08:17:30,080 --> 08:17:31,080
this ending principle which is really
11433
08:17:32,700 --> 08:17:33,700
going to come in handy again this is
11434
08:17:34,440 --> 08:17:35,440
something that we only have to do now
11435
08:17:35,820 --> 08:17:36,820
with ipv4 IPv6 doesn't have to do it and
11436
08:17:39,298 --> 08:17:40,298
we'll describe why finally we're going
11437
08:17:41,280 --> 08:17:42,280
to take a look at what are called custom
11438
08:17:42,958 --> 08:17:43,958
subnet masks which are slightly
11439
08:17:44,940 --> 08:17:45,940
different from these default ones the
11440
08:17:47,040 --> 08:17:48,040
255 to 255 to 255s and so on so having
11441
08:17:51,360 --> 08:17:52,360
said all that let's get into it by
11442
08:17:53,100 --> 08:17:54,100
looking at Network addresses and names
11443
08:17:55,920 --> 08:17:56,920
so let's begin by looking at how nodes
11444
08:17:58,260 --> 08:17:59,260
on a network are identified specifically
11445
08:18:00,840 --> 08:18:01,840
on the Internet or network layer if you
11446
08:18:03,780 --> 08:18:04,780
recall the network
11447
08:18:07,558 --> 08:18:08,558
layer
11448
08:18:10,260 --> 08:18:11,260
is layer 3 of The OSI model
11449
08:18:13,200 --> 08:18:14,200
and the internet layer
11450
08:18:16,558 --> 08:18:17,558
is layer 2 of the tcpip model
11451
08:18:23,120 --> 08:18:24,120
so to begin a network address is
11452
08:18:26,700 --> 08:18:27,700
assigned to every device and I think
11453
08:18:28,440 --> 08:18:29,440
we've discussed this that wants to
11454
08:18:30,120 --> 08:18:31,120
communicate on a computer network the
11455
08:18:32,398 --> 08:18:33,398
network address is actually made up of
11456
08:18:34,500 --> 08:18:35,500
two parts the node portion that belongs
11457
08:18:38,218 --> 08:18:39,218
to the specific device and the network
11458
08:18:42,240 --> 08:18:43,240
portion which identifies what network
11459
08:18:44,458 --> 08:18:45,458
the device belongs to I think I've just
11460
08:18:47,040 --> 08:18:48,040
described this as a zip code which
11461
08:18:49,680 --> 08:18:50,680
describes the sort of network or the
11462
08:18:51,898 --> 08:18:52,898
area you're in versus your street number
11463
08:18:54,540 --> 08:18:55,540
and your street address which is
11464
08:18:56,520 --> 08:18:57,520
specific to where you live this address
11465
08:18:58,978 --> 08:18:59,978
is what is used by devices for
11466
08:19:01,500 --> 08:19:02,500
identification and as it's only made up
11467
08:19:04,378 --> 08:19:05,378
of numbers whereas a network name is
11468
08:19:07,978 --> 08:19:08,978
made up of
11469
08:19:09,958 --> 08:19:10,958
um letters and such the real reason
11470
08:19:12,718 --> 08:19:13,718
being readability we would have a lot of
11471
08:19:15,660 --> 08:19:16,660
trouble remembering we already have
11472
08:19:17,398 --> 08:19:18,398
trouble remembering a phone number but
11473
08:19:19,500 --> 08:19:20,500
if you imagine remembering a whole
11474
08:19:21,058 --> 08:19:22,058
binary number a set of numbers where
11475
08:19:22,860 --> 08:19:23,860
there infinite possibilities unless
11476
08:19:25,440 --> 08:19:26,440
you're using it a lot it's easier to
11477
08:19:26,820 --> 08:19:27,820
remember a name such as the conference
11478
08:19:30,120 --> 08:19:31,120
room laptop or resource server one than
11479
08:19:33,420 --> 08:19:34,420
it is to remember an IP address which
11480
08:19:35,700 --> 08:19:36,700
might be something like 132.168.56.43
11481
08:19:40,080 --> 08:19:41,080
especially when there are a lot more
11482
08:19:41,580 --> 08:19:42,580
computers involved the names become a
11483
08:19:44,160 --> 08:19:45,160
lot easier so the network named is
11484
08:19:46,680 --> 08:19:47,680
actually mapped to the address or the IP
11485
08:19:50,700 --> 08:19:51,700
address by one or another naming
11486
08:19:53,340 --> 08:19:54,340
services and some of these we've
11487
08:19:54,780 --> 08:19:55,780
discussed now as devices only
11488
08:19:56,940 --> 08:19:57,940
communicate with each other by their
11489
08:19:58,978 --> 08:19:59,978
Network address the naming service is a
11490
08:20:01,378 --> 08:20:02,378
really crucial to the operation of a
11491
08:20:03,600 --> 08:20:04,600
network there are three different
11492
08:20:05,340 --> 08:20:06,340
network Services used that you should be
11493
08:20:07,740 --> 08:20:08,740
aware of the first DNS which we've
11494
08:20:10,138 --> 08:20:11,138
mentioned before also called the domain
11495
08:20:12,780 --> 08:20:13,780
name service is an Aiming service that's
11496
08:20:15,240 --> 08:20:16,240
used on the internet in most networks
11497
08:20:17,340 --> 08:20:18,340
it's what allows for instance you to
11498
08:20:19,440 --> 08:20:20,440
type in Google
11499
08:20:21,660 --> 08:20:22,660
dot com which we would call a fully
11500
08:20:25,378 --> 08:20:26,378
qualified domain name and it will
11501
08:20:28,978 --> 08:20:29,978
translate that to the IP address of
11502
08:20:32,638 --> 08:20:33,638
Google whatever that might be
11503
08:20:34,558 --> 08:20:35,558
the next naming service is Windows
11504
08:20:36,660 --> 08:20:37,660
specific and it's called wins or the
11505
08:20:39,120 --> 08:20:40,120
windows internet naming service it's
11506
08:20:41,760 --> 08:20:42,760
really outdated and it was used on
11507
08:20:44,580 --> 08:20:45,580
Windows networks the only reason I
11508
08:20:46,860 --> 08:20:47,860
mention it is you might see it mentioned
11509
08:20:49,138 --> 08:20:50,138
in a test question and it might help you
11510
08:20:51,000 --> 08:20:52,000
but you're really not going to see it
11511
08:20:52,500 --> 08:20:53,500
used in the field much anymore and
11512
08:20:55,200 --> 08:20:56,200
finally we have one called net bios
11513
08:20:57,718 --> 08:20:58,718
which is a broadcast type of service
11514
08:21:00,120 --> 08:21:01,120
that has a maximum length of uh 15
11515
08:21:04,558 --> 08:21:05,558
characters
11516
08:21:08,160 --> 08:21:09,160
and it was used or still is used to a
11517
08:21:11,458 --> 08:21:12,458
certain extent on Windows networks as
11518
08:21:13,320 --> 08:21:14,320
well a good understanding of all of
11519
08:21:15,660 --> 08:21:16,660
these Network identification aspects
11520
08:21:17,898 --> 08:21:18,898
addresses and names is important at this
11521
08:21:21,898 --> 08:21:22,898
very fundamental level
11522
08:21:23,398 --> 08:21:24,398
so now that we sort of have a general
11523
08:21:25,020 --> 08:21:26,020
overview of these let's take a look at
11524
08:21:27,780 --> 08:21:28,780
some of the specific type of network
11525
08:21:29,520 --> 08:21:30,520
addressing specifically
11526
08:21:31,760 --> 08:21:32,760
ipv4 now ipv4 ipv4 addresses is a very
11527
08:21:37,740 --> 08:21:38,740
important aspect of networking for any
11528
08:21:41,100 --> 08:21:42,100
administrator or technician or even just
11529
08:21:44,100 --> 08:21:45,100
you know it guy to understand
11530
08:21:47,580 --> 08:21:48,580
it is a 32-bit binary address that's
11531
08:21:51,958 --> 08:21:52,958
used to identify and differentiate nodes
11532
08:21:54,898 --> 08:21:55,898
on a network in other words it is your
11533
08:21:58,138 --> 08:21:59,138
address on the network or your social
11534
08:22:00,780 --> 08:22:01,780
security number with the ipv4 addressing
11535
08:22:04,260 --> 08:22:05,260
scheme being a 32-bit address and you
11536
08:22:07,860 --> 08:22:08,860
can see if we counted each one of these
11537
08:22:09,660 --> 08:22:10,660
up remember a bit is either 0 or 1 and
11538
08:22:13,080 --> 08:22:14,080
we can count up there are 32 of these
11539
08:22:15,478 --> 08:22:16,478
this means that there are theoretically
11540
08:22:17,360 --> 08:22:18,360
up to
11541
08:22:19,638 --> 08:22:20,638
4.29 billion
11542
08:22:23,180 --> 08:22:24,180
addresses available now that might not
11543
08:22:26,638 --> 08:22:27,638
sound uh like we're ever going to hit
11544
08:22:28,680 --> 08:22:29,680
that but in fact we've already gotten
11545
08:22:30,718 --> 08:22:31,718
there and so part of the problem is how
11546
08:22:32,638 --> 08:22:33,638
do we share 4.29 billion devices with
11547
08:22:36,180 --> 08:22:37,180
our 4.29 billion addresses with even
11548
08:22:39,600 --> 08:22:40,600
more billions devices in the world so
11549
08:22:42,780 --> 08:22:43,780
this 32-bit address which is why we've
11550
08:22:45,660 --> 08:22:46,660
had to develop another one called IPv6
11551
08:22:48,478 --> 08:22:49,478
but anyway I digress the 32-bit address
11552
08:22:51,660 --> 08:22:52,660
is broken up into four octets this makes
11553
08:22:55,920 --> 08:22:56,920
it easier for people to remember and to
11554
08:22:58,558 --> 08:22:59,558
read
11555
08:22:59,520 --> 08:23:00,520
and you can see those here and if you've
11556
08:23:02,100 --> 08:23:03,100
ever seen like a
11557
08:23:03,920 --> 08:23:04,920
192.168.0.1 those are the four octets
11558
08:23:06,660 --> 08:23:07,660
this system and structure of these
11559
08:23:08,760 --> 08:23:09,760
address schemes is governed and managed
11560
08:23:10,920 --> 08:23:11,920
by two standard organizations one is
11561
08:23:13,440 --> 08:23:14,440
called the a i a n a
11562
08:23:17,700 --> 08:23:18,700
which stands for the internet assigned
11563
08:23:19,920 --> 08:23:20,920
numbers Authority and the other is
11564
08:23:21,958 --> 08:23:22,958
called the rir or the regional internet
11565
08:23:24,600 --> 08:23:25,600
registry I wouldn't worry about
11566
08:23:26,520 --> 08:23:27,520
memorizing these I'm just mentioning
11567
08:23:28,020 --> 08:23:29,020
them so you know sort of who's coming up
11568
08:23:29,878 --> 08:23:30,878
with all this stuff
11569
08:23:31,138 --> 08:23:32,138
now every device on the network is going
11570
08:23:33,240 --> 08:23:34,240
to have its own unique address
11571
08:23:36,180 --> 08:23:37,180
so there are two types of addresses in
11572
08:23:39,780 --> 08:23:40,780
general one is called class full and
11573
08:23:42,180 --> 08:23:43,180
these are default addresses and the
11574
08:23:44,580 --> 08:23:45,580
other are called class less which are
11575
08:23:46,500 --> 08:23:47,500
custom addresses we're going to talk
11576
08:23:48,540 --> 08:23:49,540
about the class less ones in a later
11577
08:23:51,240 --> 08:23:52,240
module and we're going to Define both of
11578
08:23:53,940 --> 08:23:54,940
these in Greater detail a little bit
11579
08:23:56,218 --> 08:23:57,218
later on
11580
08:23:57,540 --> 08:23:58,540
as a network address it's also made up
11581
08:23:59,638 --> 08:24:00,638
of two parts the network portion and the
11582
08:24:03,540 --> 08:24:04,540
node portion let me just erase all this
11583
08:24:05,280 --> 08:24:06,280
writing here so you can see exactly what
11584
08:24:06,898 --> 08:24:07,898
I mean in order to tell now in this
11585
08:24:09,958 --> 08:24:10,958
section
11586
08:24:11,340 --> 08:24:12,340
you can see the network portion are the
11587
08:24:13,080 --> 08:24:14,080
first two octets and the node portion of
11588
08:24:15,478 --> 08:24:16,478
the last two octets but that is not
11589
08:24:17,340 --> 08:24:18,340
always the case in fact if we were to
11590
08:24:19,978 --> 08:24:20,978
just take those away for a second uh and
11591
08:24:22,620 --> 08:24:23,620
this is how the computer looks at them
11592
08:24:24,120 --> 08:24:25,120
we can't actually tell which is which
11593
08:24:26,280 --> 08:24:27,280
and that's why we need something called
11594
08:24:28,138 --> 08:24:29,138
a subnet mask the subnet mask allows us
11595
08:24:30,780 --> 08:24:31,780
to determine which is the network
11596
08:24:32,458 --> 08:24:33,458
portion and which is the node portion
11597
08:24:35,398 --> 08:24:36,398
that way we know for instance where the
11598
08:24:38,458 --> 08:24:39,458
area code of the phone number begins and
11599
08:24:41,580 --> 08:24:42,580
the rest of the number ends so the
11600
08:24:43,378 --> 08:24:44,378
network portion would be like the area
11601
08:24:45,000 --> 08:24:46,000
code of your phone number or the
11602
08:24:47,100 --> 08:24:48,100
international code it tells you which
11603
08:24:48,840 --> 08:24:49,840
network that is on the Node portion
11604
08:24:51,360 --> 08:24:52,360
tells you exactly which phone on that
11605
08:24:53,340 --> 08:24:54,340
Network we're going to try reaching out
11606
08:24:54,958 --> 08:24:55,958
to so we're going to further logically
11607
08:24:58,620 --> 08:24:59,620
again not physically divide a network
11608
08:25:01,740 --> 08:25:02,740
into smaller sub networks called sub
11609
08:25:05,520 --> 08:25:06,520
Nets
11610
08:25:07,680 --> 08:25:08,680
now this logical division is beneficial
11611
08:25:10,500 --> 08:25:11,500
because of three reasons one it can
11612
08:25:14,100 --> 08:25:15,100
effectively increase the efficiency in
11613
08:25:16,558 --> 08:25:17,558
packet routing because if I know that my
11614
08:25:20,580 --> 08:25:21,580
information is destined for a specific
11615
08:25:23,340 --> 08:25:24,340
Network I don't have to bother with
11616
08:25:25,440 --> 08:25:26,440
asking let's say 5 000 or 5 million or
11617
08:25:28,138 --> 08:25:29,138
five billion computers if I'm meant for
11618
08:25:30,840 --> 08:25:31,840
them I can go directly to the network
11619
08:25:33,000 --> 08:25:34,000
where I want to go just like with area
11620
08:25:35,040 --> 08:25:36,040
codes and phone numbers the next is it
11621
08:25:37,500 --> 08:25:38,500
allows for better management of multiple
11622
08:25:39,478 --> 08:25:40,478
networks within a single Organization
11623
08:25:41,240 --> 08:25:42,240
for instance if I'm a network
11624
08:25:43,378 --> 08:25:44,378
administrator it might be easier to have
11625
08:25:45,718 --> 08:25:46,718
separate subnets so I can organize who's
11626
08:25:48,958 --> 08:25:49,958
on which subnet so that way not only are
11627
08:25:51,660 --> 08:25:52,660
things going to be routed more
11628
08:25:53,100 --> 08:25:54,100
efficiently for that person but it's
11629
08:25:54,660 --> 08:25:55,660
easier for me to manage on paper and uh
11630
08:25:57,780 --> 08:25:58,780
in my administrative duties and finally
11631
08:26:00,240 --> 08:26:01,240
it potentially offers a certain level of
11632
08:26:02,040 --> 08:26:03,040
security since I'm only going to be able
11633
08:26:04,620 --> 08:26:05,620
to access easily information that's on
11634
08:26:07,138 --> 08:26:08,138
the same net work or sub Network that
11635
08:26:09,000 --> 08:26:10,000
I'm on
11636
08:26:10,080 --> 08:26:11,080
now a subnetted ipv4 address is actually
11637
08:26:13,320 --> 08:26:14,320
comprised of three different parts the
11638
08:26:16,320 --> 08:26:17,320
netid
11639
08:26:17,760 --> 08:26:18,760
the host ID
11640
08:26:19,620 --> 08:26:20,620
and the subnet ID
11641
08:26:22,500 --> 08:26:23,500
now if a device on a subnetted tcpip
11642
08:26:25,680 --> 08:26:26,680
network wants to communicate it's going
11643
08:26:28,200 --> 08:26:29,200
to need to be configured with an IP
11644
08:26:30,958 --> 08:26:31,958
address and a subnet mask and we'll look
11645
08:26:33,840 --> 08:26:34,840
at these in just a second the subnet
11646
08:26:35,940 --> 08:26:36,940
mask is what is used to identify the
11647
08:26:39,240 --> 08:26:40,240
subnet that each node belongs to this
11648
08:26:42,600 --> 08:26:43,600
also allows us to determine which
11649
08:26:44,398 --> 08:26:45,398
network it's on connectivity devices
11650
08:26:47,280 --> 08:26:48,280
such as routers or upper layer switches
11651
08:26:50,280 --> 08:26:51,280
and we're talking about layer 3 devices
11652
08:26:53,218 --> 08:26:54,218
here and remember layer 3 devices look
11653
08:26:55,978 --> 08:26:56,978
at IP addresses
11654
08:26:58,200 --> 08:26:59,200
not just Mac addresses
11655
08:27:01,378 --> 08:27:02,378
are used on the borders of these
11656
08:27:03,718 --> 08:27:04,718
networks to manage the data passage
11657
08:27:06,058 --> 08:27:07,058
between and within the network that's
11658
08:27:08,398 --> 08:27:09,398
how we're going to get better routing
11659
08:27:09,718 --> 08:27:10,718
efficiency easier management and
11660
08:27:11,580 --> 08:27:12,580
potentially make it more secure because
11661
08:27:13,620 --> 08:27:14,620
if I have any one network and I have a
11662
08:27:17,100 --> 08:27:18,100
let's say a switch
11663
08:27:19,500 --> 08:27:20,500
we'll put this a switch and it has four
11664
08:27:22,138 --> 08:27:23,138
computers on it and then I have another
11665
08:27:23,878 --> 08:27:24,878
switch
11666
08:27:25,200 --> 08:27:26,200
and these are layer 2 switches okay
11667
08:27:30,958 --> 08:27:31,958
and each of these let's say we have our
11668
08:27:33,660 --> 08:27:34,660
different subnets then I'm going to
11669
08:27:35,760 --> 08:27:36,760
divide these up
11670
08:27:38,760 --> 08:27:39,760
by a router which now is going to make
11671
08:27:41,340 --> 08:27:42,340
sure that data that's going here kind of
11672
08:27:43,740 --> 08:27:44,740
gets bounced back unless it's meant for
11673
08:27:46,138 --> 08:27:47,138
this guy and this way we're really
11674
08:27:47,340 --> 08:27:48,340
reducing the traffic on it
11675
08:27:49,798 --> 08:27:50,798
now a subnet mask is like an IP address
11676
08:27:53,040 --> 08:27:54,040
a 32-bit binary address broken up into
11677
08:27:57,478 --> 08:27:58,478
four octets and a dotted decimal format
11678
08:28:00,478 --> 08:28:01,478
just like an IP address
11679
08:28:03,180 --> 08:28:04,180
and it's used to separate the network
11680
08:28:06,120 --> 08:28:07,120
portion from the node portion I'm going
11681
08:28:08,940 --> 08:28:09,940
to show you how that works in just a
11682
08:28:10,500 --> 08:28:11,500
minute and it involves a little bit
11683
08:28:12,120 --> 08:28:13,120
knowledge of binary which we've already
11684
08:28:13,558 --> 08:28:14,558
talked about so the subnet mask and that
11685
08:28:16,558 --> 08:28:17,558
name mask sort of lets you think of it
11686
08:28:19,378 --> 08:28:20,378
as being put onto the IP address is
11687
08:28:22,020 --> 08:28:23,020
applied to that IP address and removes
11688
08:28:24,718 --> 08:28:25,718
the node ID the subnet mask therefore
11689
08:28:27,478 --> 08:28:28,478
eliminates removes an entire octet of
11690
08:28:30,360 --> 08:28:31,360
the IP address by using eight binary
11691
08:28:33,240 --> 08:28:34,240
ones or 255 in decimal format meaning
11692
08:28:36,478 --> 08:28:37,478
that this 255 if we add it up in binary
11693
08:28:40,378 --> 08:28:41,378
would be one two three four five six
11694
08:28:43,740 --> 08:28:44,740
seven eight
11695
08:28:45,780 --> 08:28:46,780
one two three four five six seven eight
11696
08:28:49,218 --> 08:28:50,218
one two three four five six seven eight
11697
08:28:52,798 --> 08:28:53,798
and then this would be one two three
11698
08:28:56,040 --> 08:28:57,040
four five six seven eight so meaning
11699
08:28:58,798 --> 08:28:59,798
that a 255 equals eight
11700
08:29:02,458 --> 08:29:03,458
ones which is the reason why an IP
11701
08:29:04,978 --> 08:29:05,978
address can never be 255. and if this is
11702
08:29:08,700 --> 08:29:09,700
a little confusing that's okay we're
11703
08:29:09,840 --> 08:29:10,840
about to clarify that in just a second
11704
08:29:12,120 --> 08:29:13,120
so IP addresses IP address assignments
11705
08:29:16,978 --> 08:29:17,978
and subnet masks all have to follow a
11706
08:29:19,920 --> 08:29:20,920
certain set of rules I'm going to
11707
08:29:21,600 --> 08:29:22,600
describe the rules and then I'm going to
11708
08:29:22,978 --> 08:29:23,978
apply them so if some of this is a
11709
08:29:25,138 --> 08:29:26,138
little confusing or over your head keep
11710
08:29:27,000 --> 08:29:28,000
paying attention keep with me and I
11711
08:29:28,798 --> 08:29:29,798
think it's going to clarify itself
11712
08:29:30,660 --> 08:29:31,660
the first is that the ones in a subnet
11713
08:29:35,100 --> 08:29:36,100
mask will always start at the left
11714
08:29:38,298 --> 08:29:39,298
meaning the first octet will always be
11715
08:29:42,740 --> 08:29:43,740
255 or 8 binary ones so my I my subnet
11716
08:29:48,240 --> 08:29:49,240
mask I'm always going to start at the
11717
08:29:49,558 --> 08:29:50,558
left when I'm writing it out
11718
08:29:57,660 --> 08:29:58,660
this says that the first octet is going
11719
08:30:00,540 --> 08:30:01,540
to be 255 which means 8 Bits
11720
08:30:03,478 --> 08:30:04,478
now the zeros of the Mask will always
11721
08:30:06,000 --> 08:30:07,000
start
11722
08:30:07,080 --> 08:30:08,080
at the one bit
11723
08:30:08,820 --> 08:30:09,820
or all the way on the right
11724
08:30:10,978 --> 08:30:11,978
meaning that I'm going to have zeros
11725
08:30:13,080 --> 08:30:14,080
from the right
11726
08:30:14,638 --> 08:30:15,638
and ones from the left
11727
08:30:16,680 --> 08:30:17,680
and the ones in The Mask have to be
11728
08:30:19,740 --> 08:30:20,740
adjoining adjoining or con consistent or
11729
08:30:24,000 --> 08:30:25,000
continuous or contiguous whichever word
11730
08:30:26,100 --> 08:30:27,100
you want to use meaning once there is a
11731
08:30:28,860 --> 08:30:29,860
zero we cannot then go back to ones so
11732
08:30:32,940 --> 08:30:33,940
we're not going to see like this sort of
11733
08:30:34,860 --> 08:30:35,860
thing happen
11734
08:30:36,898 --> 08:30:37,898
in fact we have to have continuous ones
11735
08:30:39,958 --> 08:30:40,958
from the left and continuous zeros from
11736
08:30:42,898 --> 08:30:43,898
the right
11737
08:30:43,740 --> 08:30:44,740
this is the only way a subnet mask is
11738
08:30:45,958 --> 08:30:46,958
going to work and I'll talk about why in
11739
08:30:48,000 --> 08:30:49,000
just a minute
11740
08:30:49,798 --> 08:30:50,798
also if there is more than one subnet on
11741
08:30:52,500 --> 08:30:53,500
a network every subnet has to have a
11742
08:30:55,798 --> 08:30:56,798
unique network ID and I'll explain this
11743
08:30:58,860 --> 08:30:59,860
in a bit but it makes sense if I have a
11744
08:31:01,920 --> 08:31:02,920
different network IDs
11745
08:31:04,260 --> 08:31:05,260
then I'm not really I'm sorry if I have
11746
08:31:06,898 --> 08:31:07,898
similar Network IDs then I'm not really
11747
08:31:09,058 --> 08:31:10,058
dealing with multiple networks I'm
11748
08:31:11,160 --> 08:31:12,160
dealing with the same network
11749
08:31:12,780 --> 08:31:13,780
now assignment of IP addresses have to
11750
08:31:15,780 --> 08:31:16,780
follow a few more rules so these are the
11751
08:31:17,458 --> 08:31:18,458
subnet masks first there cannot be any
11752
08:31:20,280 --> 08:31:21,280
duplicate IP addresses on the network
11753
08:31:23,180 --> 08:31:24,180
this means that every Network every
11754
08:31:26,160 --> 08:31:27,160
device has to have its own unique
11755
08:31:29,458 --> 08:31:30,458
IP address we cannot have more than one
11756
08:31:32,820 --> 08:31:33,820
device with the same IP address if we do
11757
08:31:35,040 --> 08:31:36,040
they're not going to communicate because
11758
08:31:36,780 --> 08:31:37,780
the switches won't know where to send
11759
08:31:38,820 --> 08:31:39,820
packets next if there are subnets every
11760
08:31:42,718 --> 08:31:43,718
node must be assigned to one of them
11761
08:31:45,058 --> 08:31:46,058
meaning that every address every IP
11762
08:31:48,180 --> 08:31:49,180
address has to be assigned to a specific
11763
08:31:50,340 --> 08:31:51,340
Network
11764
08:31:52,398 --> 08:31:53,398
now the address of a known cannot be all
11765
08:31:56,520 --> 08:31:57,520
ones or all zeros remember all ones
11766
08:31:59,040 --> 08:32:00,040
would be 255. all zeros would be just
11767
08:32:02,780 --> 08:32:03,780
0.0.0.0 so I cannot have an IP address
11768
08:32:05,638 --> 08:32:06,638
that is either
11769
08:32:08,898 --> 08:32:09,898
255.255.255 or that can be
11770
08:32:12,440 --> 08:32:13,440
0.0.0.0 and you'll see why when we get
11771
08:32:15,420 --> 08:32:16,420
to the mathematics of this in just a
11772
08:32:17,280 --> 08:32:18,280
second it's because then I would never
11773
08:32:19,080 --> 08:32:20,080
be able to determine a network ID from a
11774
08:32:22,020 --> 08:32:23,020
node ID
11775
08:32:23,340 --> 08:32:24,340
finally and this is something you sort
11776
08:32:25,620 --> 08:32:26,620
of have to remember the IP address can
11777
08:32:27,840 --> 08:32:28,840
never be
11778
08:32:29,898 --> 08:32:30,898
127.0.0.1 we've talked about this in um
11779
08:32:33,718 --> 08:32:34,718
a plus but that's because this is what's
11780
08:32:35,340 --> 08:32:36,340
called the loopback it's a reserved IP
11781
08:32:37,920 --> 08:32:38,920
address specifically for yourself be
11782
08:32:40,680 --> 08:32:41,680
like saying me myself or I I cannot have
11783
08:32:45,000 --> 08:32:46,000
a a
11784
08:32:47,298 --> 08:32:48,298
127.0.0.1 IP address assigned to a
11785
08:32:50,040 --> 08:32:51,040
device because every device calls itself
11786
08:32:52,378 --> 08:32:53,378
127.0.0.1
11787
08:32:55,320 --> 08:32:56,320
now besides understanding these rules
11788
08:32:57,840 --> 08:32:58,840
which are a bit abstract I think we need
11789
08:33:00,240 --> 08:33:01,240
to know how to apply them and how to
11790
08:33:02,218 --> 08:33:03,218
apply a subnet mask to an IP address I
11791
08:33:04,860 --> 08:33:05,860
think it's going to make some of these
11792
08:33:05,820 --> 08:33:06,820
rules a little clearer so let's take a
11793
08:33:07,320 --> 08:33:08,320
look at those now when a subnet mask is
11794
08:33:10,020 --> 08:33:11,020
applied to an IP address
11795
08:33:12,360 --> 08:33:13,360
the remainder is the network portion
11796
08:33:14,940 --> 08:33:15,940
meaning when we take the IP address and
11797
08:33:16,978 --> 08:33:17,978
we apply the subnet mask and I'll show
11798
08:33:18,478 --> 08:33:19,478
you how to do that in a second what we
11799
08:33:20,280 --> 08:33:21,280
get as a remainder what's left over is
11800
08:33:22,080 --> 08:33:23,080
going to be the network ID this allows
11801
08:33:24,180 --> 08:33:25,180
us to then determine what the node ID is
11802
08:33:26,040 --> 08:33:27,040
this will make more sense in just a
11803
08:33:27,478 --> 08:33:28,478
minute the way we do this is through
11804
08:33:28,978 --> 08:33:29,978
something called anding ending is a
11805
08:33:31,200 --> 08:33:32,200
mathematics term it really has to do
11806
08:33:32,820 --> 08:33:33,820
with Logic the way it works is and you
11807
08:33:35,820 --> 08:33:36,820
just have to sort of remember these
11808
08:33:37,020 --> 08:33:38,020
rules
11809
08:33:37,920 --> 08:33:38,920
one
11810
08:33:40,218 --> 08:33:41,218
and one
11811
08:33:42,958 --> 08:33:43,958
is one
11812
08:33:44,878 --> 08:33:45,878
one
11813
08:33:46,440 --> 08:33:47,440
and zero
11814
08:33:48,420 --> 08:33:49,420
is zero and the trick there is that that
11815
08:33:50,638 --> 08:33:51,638
zero is there
11816
08:33:52,378 --> 08:33:53,378
zero
11817
08:33:54,958 --> 08:33:55,958
and one
11818
08:33:57,120 --> 08:33:58,120
is zero
11819
08:33:58,860 --> 08:33:59,860
and zero
11820
08:34:00,718 --> 08:34:01,718
and zero is also zero so basically what
11821
08:34:04,320 --> 08:34:05,320
anding does is allows us to hide
11822
08:34:07,620 --> 08:34:08,620
certain
11823
08:34:09,180 --> 08:34:10,180
um address certain bits
11824
08:34:11,820 --> 08:34:12,820
from the rest of the network and
11825
08:34:14,700 --> 08:34:15,700
therefore we're allowed to get the IP
11826
08:34:17,398 --> 08:34:18,398
address or rather the network address
11827
08:34:19,860 --> 08:34:20,860
from the node address
11828
08:34:21,718 --> 08:34:22,718
so let's take a look at this for just a
11829
08:34:23,520 --> 08:34:24,520
second let's say we have an IP address
11830
08:34:29,180 --> 08:34:30,180
162.85.120.27 and we have a subnet mask
11831
08:34:31,798 --> 08:34:32,798
of 255.255.255.0
11832
08:34:36,058 --> 08:34:37,058
now let's take a look at how this works
11833
08:34:38,638 --> 08:34:39,638
when we move it into binary
11834
08:34:42,558 --> 08:34:43,558
162.85.120.127 equals this in binary and
11835
08:34:45,478 --> 08:34:46,478
if we wanted to write out these places
11836
08:34:48,600 --> 08:34:49,600
again if you remember we had this was a
11837
08:34:51,718 --> 08:34:52,718
base two
11838
08:34:53,040 --> 08:34:54,040
right so these are the place settings
11839
08:34:57,298 --> 08:34:58,298
I'm just going to write these out real
11840
08:34:58,680 --> 08:34:59,680
quickly and then I'm going to erase it
11841
08:34:59,940 --> 08:35:00,940
all
11842
08:35:03,780 --> 08:35:04,780
okay
11843
08:35:04,978 --> 08:35:05,978
and so we get one
11844
08:35:06,840 --> 08:35:07,840
two four
11845
08:35:09,478 --> 08:35:10,478
eight
11846
08:35:10,760 --> 08:35:11,760
sixteen thirty two sixty four
11847
08:35:15,378 --> 08:35:16,378
128 and it's good to sort of commit
11848
08:35:17,760 --> 08:35:18,760
these to memory therefore the reason
11849
08:35:19,798 --> 08:35:20,798
this is one one one is we take that 128
11850
08:35:24,718 --> 08:35:25,718
we add it to 32 and we add it to the 2
11851
08:35:28,200 --> 08:35:29,200
because those are the bits that are on
11852
08:35:30,958 --> 08:35:31,958
and when we add 128 plus 32
11853
08:35:36,898 --> 08:35:37,898
we get 160
11854
08:35:39,780 --> 08:35:40,780
plus 2 gives us 1 62. so it works out
11855
08:35:44,340 --> 08:35:45,340
and you can see my math is correct here
11856
08:35:45,958 --> 08:35:46,958
I'm going to erase all this now try to
11857
08:35:48,180 --> 08:35:49,180
remember this and thing in here for a
11858
08:35:50,218 --> 08:35:51,218
minute
11859
08:35:51,600 --> 08:35:52,600
now if we convert
11860
08:35:54,680 --> 08:35:55,680
255.255.255.0 into binary we've already
11861
08:35:57,180 --> 08:35:58,180
talked about this we're going to get
11862
08:35:58,978 --> 08:35:59,978
all these ones and then because this is
11863
08:36:01,378 --> 08:36:02,378
zero we're gonna get zero now if we
11864
08:36:04,440 --> 08:36:05,440
apply the anding principle
11865
08:36:07,798 --> 08:36:08,798
this is what we're going to get
11866
08:36:09,540 --> 08:36:10,540
anything with one and one turns into one
11867
08:36:12,898 --> 08:36:13,898
anytime we see a one and a zero we're
11868
08:36:15,718 --> 08:36:16,718
going to get a zero and if we apply this
11869
08:36:17,760 --> 08:36:18,760
out
11870
08:36:19,798 --> 08:36:20,798
here's what we get now because we have
11871
08:36:21,898 --> 08:36:22,898
all these zeros here it's basically
11872
08:36:24,000 --> 08:36:25,000
going to block all these ones from
11873
08:36:26,040 --> 08:36:27,040
coming down and coming through
11874
08:36:28,200 --> 08:36:29,200
right they all turn into zero
11875
08:36:32,700 --> 08:36:33,700
so if we convert this back into a
11876
08:36:35,638 --> 08:36:36,638
decimal we now get 162.85.120.0
11877
08:36:41,160 --> 08:36:42,160
basically this is pretty simple to see
11878
08:36:43,680 --> 08:36:44,680
we can see that the 162 drops down the 8
11879
08:36:46,978 --> 08:36:47,978
5 drops down the 120 drops down because
11880
08:36:49,920 --> 08:36:50,920
of this ending that we just talked about
11881
08:36:52,740 --> 08:36:53,740
and the 27 gets blocked might be zeros
11882
08:36:57,240 --> 08:36:58,240
and so we can determine
11883
08:36:59,520 --> 08:37:00,520
that the
11884
08:37:01,280 --> 08:37:02,280
162.85.120 is what we call
11885
08:37:05,040 --> 08:37:06,040
the network
11886
08:37:08,160 --> 08:37:09,160
ID
11887
08:37:10,138 --> 08:37:11,138
Now by looking at it this way we can see
11888
08:37:12,240 --> 08:37:13,240
then that the network portion of the
11889
08:37:14,280 --> 08:37:15,280
address is going to be the first three
11890
08:37:17,160 --> 08:37:18,160
octets as we just pointed out and the
11891
08:37:19,920 --> 08:37:20,920
node portion is going to be the last
11892
08:37:22,320 --> 08:37:23,320
octet
11893
08:37:23,820 --> 08:37:24,820
so this is the first step in subnetting
11894
08:37:26,218 --> 08:37:27,218
and it tells us a lot of things about
11895
08:37:27,600 --> 08:37:28,600
the networks just by knowing the IP
11896
08:37:30,120 --> 08:37:31,120
address and the subnet mask a technician
11897
08:37:32,398 --> 08:37:33,398
can now discern a lot of things such as
11898
08:37:35,100 --> 08:37:36,100
what portion is the network ID what
11899
08:37:37,620 --> 08:37:38,620
portion is the node ID
11900
08:37:40,080 --> 08:37:41,080
and therefore what is my first usable IP
11901
08:37:43,080 --> 08:37:44,080
address and what's my last usable IP
11902
08:37:45,420 --> 08:37:46,420
address that I could start to give to
11903
08:37:48,180 --> 08:37:49,180
devices
11904
08:37:49,260 --> 08:37:50,260
I can also determine stuff like what we
11905
08:37:51,660 --> 08:37:52,660
call the default gateway which we'll
11906
08:37:53,520 --> 08:37:54,520
look at in a second
11907
08:37:57,000 --> 08:37:58,000
and
11908
08:37:58,620 --> 08:37:59,620
the broadcast address which will also
11909
08:38:00,718 --> 08:38:01,718
look look at not in a second then in the
11910
08:38:03,180 --> 08:38:04,180
next module
11911
08:38:06,600 --> 08:38:07,600
now there are three default subnet masks
11912
08:38:10,138 --> 08:38:11,138
as you can imagine
11913
08:38:12,540 --> 08:38:13,540
and these have to do with what we call a
11914
08:38:14,280 --> 08:38:15,280
class uh a class full IP addressing
11915
08:38:17,160 --> 08:38:18,160
system and we'll talk about that next
11916
08:38:18,360 --> 08:38:19,360
the next module but the default subnet
11917
08:38:20,760 --> 08:38:21,760
masks are 255.0.0.0
11918
08:38:23,458 --> 08:38:24,458
just going to go with the class A and
11919
08:38:24,840 --> 08:38:25,840
we'll talk about that
11920
08:38:27,260 --> 08:38:28,260
255.255.0.0 and 255.255.255.0
11921
08:38:30,898 --> 08:38:31,898
what you can see is if you have a
11922
08:38:32,638 --> 08:38:33,638
default subnet mask then you know
11923
08:38:35,340 --> 08:38:36,340
immediately just by looking
11924
08:38:37,620 --> 08:38:38,620
what the network address is and what the
11925
08:38:39,958 --> 08:38:40,958
node address is
11926
08:38:41,218 --> 08:38:42,218
as you can imagine
11927
08:38:42,898 --> 08:38:43,898
if I have this as my network address
11928
08:38:46,200 --> 08:38:47,200
I can have a lot of Networks and only so
11929
08:38:50,160 --> 08:38:51,160
many nodes this one I have
11930
08:38:53,878 --> 08:38:54,878
more nodes a little bit less networks
11931
08:38:57,000 --> 08:38:58,000
and this one I have a lot of nodes but
11932
08:38:58,920 --> 08:38:59,920
fewer networks to divide them up on
11933
08:39:01,200 --> 08:39:02,200
now would be great if all subnet masks
11934
08:39:03,298 --> 08:39:04,298
were as simple as this we wouldn't even
11935
08:39:04,798 --> 08:39:05,798
really ever have to break it down into
11936
08:39:07,260 --> 08:39:08,260
this binary sort of coding because you
11937
08:39:10,020 --> 08:39:11,020
could just look at it and say oh it's
11938
08:39:11,160 --> 08:39:12,160
255 I know they're all going to be ones
11939
08:39:12,840 --> 08:39:13,840
I know that's going to end out and
11940
08:39:14,700 --> 08:39:15,700
therefore I know it's going to end up
11941
08:39:15,958 --> 08:39:16,958
right here
11942
08:39:17,040 --> 08:39:18,040
but unfortunately this is not always the
11943
08:39:18,840 --> 08:39:19,840
case sometimes we have what are called
11944
08:39:19,978 --> 08:39:20,978
custom subnet masks Now by using a
11945
08:39:23,398 --> 08:39:24,398
custom subnet mask we can actually
11946
08:39:24,840 --> 08:39:25,840
further divide or subdivide our IP
11947
08:39:27,660 --> 08:39:28,660
address and in these cases it can be a
11948
08:39:29,638 --> 08:39:30,638
little more difficult uh and so
11949
08:39:32,218 --> 08:39:33,218
converting to Binary is actually
11950
08:39:33,840 --> 08:39:34,840
necessary to break it down custom subnet
11951
08:39:36,898 --> 08:39:37,898
masks are created by what we call
11952
08:39:39,540 --> 08:39:40,540
borrowing bits
11953
08:39:41,940 --> 08:39:42,940
from the host portion to use to identify
11954
08:39:45,420 --> 08:39:46,420
the subnet motion so you can see we've
11955
08:39:47,340 --> 08:39:48,340
just borrowed a bit this one right over
11956
08:39:49,978 --> 08:39:50,978
here
11957
08:39:50,760 --> 08:39:51,760
now keeping in mind that the subnet mask
11958
08:39:52,558 --> 08:39:53,558
rules allow us to borrow bits from the
11959
08:39:54,718 --> 08:39:55,718
node portion and give them to the
11960
08:39:57,478 --> 08:39:58,478
network portion the bits from the left
11961
08:40:00,000 --> 08:40:01,000
to the right of the portion
11962
08:40:02,160 --> 08:40:03,160
like this
11963
08:40:04,260 --> 08:40:05,260
are switched on
11964
08:40:06,420 --> 08:40:07,420
now turning this bit on means we now
11965
08:40:08,218 --> 08:40:09,218
have different values for the subnet
11966
08:40:09,958 --> 08:40:10,958
mask instead of just 255
11967
08:40:13,280 --> 08:40:14,280
.255.
11968
08:40:15,000 --> 08:40:16,000
255.
11969
08:40:17,280 --> 08:40:18,280
dot zero we know this is no longer zero
11970
08:40:19,680 --> 08:40:20,680
right so this is actually now going to
11971
08:40:21,840 --> 08:40:22,840
be
11972
08:40:22,440 --> 08:40:23,440
128.
11973
08:40:25,020 --> 08:40:26,020
and we can have a a number of these and
11974
08:40:28,080 --> 08:40:29,080
if you keep adding over to the right
11975
08:40:30,478 --> 08:40:31,478
so 128 and then we added 64. we'd get
11976
08:40:34,080 --> 08:40:35,080
192 and so on and so forth so we can
11977
08:40:37,200 --> 08:40:38,200
actually have a number of custom subnet
11978
08:40:39,180 --> 08:40:40,180
mask values in the last octet and that's
11979
08:40:42,660 --> 08:40:43,660
those are these and so you can see in
11980
08:40:45,420 --> 08:40:46,420
this case uh it's not really going to
11981
08:40:47,280 --> 08:40:48,280
make much of a difference when I I'll do
11982
08:40:49,080 --> 08:40:50,080
all the binary bidding because
11983
08:40:52,320 --> 08:40:53,320
you see that the zero and the zero is
11984
08:40:54,240 --> 08:40:55,240
still going to become a zero here and so
11985
08:40:56,458 --> 08:40:57,458
all of this is really going to look the
11986
08:40:58,020 --> 08:40:59,020
same and so our Network portion is
11987
08:41:00,000 --> 08:41:01,000
actually going to look the same as it
11988
08:41:01,978 --> 08:41:02,978
did before we have the same network ID
11989
08:41:03,840 --> 08:41:04,840
as we did before but let's say that this
11990
08:41:06,420 --> 08:41:07,420
was actually uh you know this number by
11991
08:41:08,878 --> 08:41:09,878
the way is the same as the one we had
11992
08:41:10,920 --> 08:41:11,920
before
11993
08:41:15,020 --> 08:41:16,020
162.85.120.27 if this was instead
11994
08:41:17,520 --> 08:41:18,520
162.85.120
11995
08:41:23,478 --> 08:41:24,478
dot I don't know one
11996
08:41:27,120 --> 08:41:28,120
128 we're gonna have an issue because
11997
08:41:29,520 --> 08:41:30,520
this is going to be on these would say
11998
08:41:31,920 --> 08:41:32,920
let's be off and when they come down
11999
08:41:34,920 --> 08:41:35,920
this is going to turn into a zero as
12000
08:41:37,080 --> 08:41:38,080
opposed to that one dropping down and so
12001
08:41:39,058 --> 08:41:40,058
it's going to change what our IP address
12002
08:41:41,878 --> 08:41:42,878
in the end looks like and so we actually
12003
08:41:44,100 --> 08:41:45,100
need to do some backward engineering to
12004
08:41:45,780 --> 08:41:46,780
get to our subnet mask now this is all
12005
08:41:47,820 --> 08:41:48,820
really complex and when we get into if
12006
08:41:49,798 --> 08:41:50,798
you ever get into Cisco you'd really
12007
08:41:51,180 --> 08:41:52,180
have to know this but for our purposes
12008
08:41:53,280 --> 08:41:54,280
you really don't need to know this that
12009
08:41:54,718 --> 08:41:55,718
in depth all right so just to recap what
12010
08:41:57,660 --> 08:41:58,660
we talked about here we got a basic
12011
08:42:00,058 --> 08:42:01,058
understanding of a lot of things not too
12012
08:42:01,920 --> 08:42:02,920
in depth and you might need to re-watch
12013
08:42:03,240 --> 08:42:04,240
this video to really get it and maybe
12014
08:42:05,100 --> 08:42:06,100
even do a little bit of exercises on
12015
08:42:07,620 --> 08:42:08,620
your own
12016
08:42:08,458 --> 08:42:09,458
first we talked about the difference
12017
08:42:10,558 --> 08:42:11,558
between a network address and a network
12018
08:42:13,500 --> 08:42:14,500
name remembering that the three network
12019
08:42:15,540 --> 08:42:16,540
name services that match a name such as
12020
08:42:18,540 --> 08:42:19,540
Bill's laptop to an address which would
12021
08:42:21,058 --> 08:42:22,058
be something like 192.168.0.1
12022
08:42:24,660 --> 08:42:25,660
uh we can use either DNS the domain name
12023
08:42:27,420 --> 08:42:28,420
service which is the most popular one
12024
08:42:30,000 --> 08:42:31,000
something called wins which is specific
12025
08:42:31,860 --> 08:42:32,860
to Windows or net bios also a Windows
12026
08:42:35,340 --> 08:42:36,340
based
12027
08:42:38,340 --> 08:42:39,340
naming system
12028
08:42:39,840 --> 08:42:40,840
the one we want to be most familiar with
12029
08:42:41,280 --> 08:42:42,280
is this this one's not really used
12030
08:42:42,780 --> 08:42:43,780
anymore netbios is still used in certain
12031
08:42:44,940 --> 08:42:45,940
instances especially in older networks
12032
08:42:46,740 --> 08:42:47,740
we then talked about the IP version 4
12033
08:42:50,280 --> 08:42:51,280
address and the things that it requires
12034
08:42:52,680 --> 08:42:53,680
including and remember a ipv4 address is
12035
08:42:55,920 --> 08:42:56,920
that 32 bit broken up into four octets
12036
08:43:00,478 --> 08:43:01,478
the reason it's called an octet is
12037
08:43:02,520 --> 08:43:03,520
because we have eight times four
12038
08:43:07,138 --> 08:43:08,138
gives us that 32 and we break it up so
12039
08:43:09,718 --> 08:43:10,718
for instance 192 is going to break down
12040
08:43:13,440 --> 08:43:14,440
to a certain amount of bits okay
12041
08:43:17,878 --> 08:43:18,878
we also talked about defining subnetting
12042
08:43:20,340 --> 08:43:21,340
in a subnet mask which the most
12043
08:43:22,558 --> 08:43:23,558
important thing it does is distinguishes
12044
08:43:28,138 --> 08:43:29,138
our Network
12045
08:43:31,378 --> 08:43:32,378
from our node
12046
08:43:33,780 --> 08:43:34,780
ID in other words what's our area code
12047
08:43:39,360 --> 08:43:40,360
and then what is our phone number
12048
08:43:43,440 --> 08:43:44,440
we can have the same phone number
12049
08:43:45,898 --> 08:43:46,898
in different area codes but they go to
12050
08:43:47,940 --> 08:43:48,940
very different people
12051
08:43:49,320 --> 08:43:50,320
we also talked about the rules of subnet
12052
08:43:51,240 --> 08:43:52,240
masks and IP addresses we can only have
12053
08:43:53,760 --> 08:43:54,760
one IP address
12054
08:43:58,798 --> 08:43:59,798
on any network
12055
08:44:02,100 --> 08:44:03,100
and we can not use
12056
08:44:06,320 --> 08:44:07,320
127.0.0.1 because that is what we call
12057
08:44:08,398 --> 08:44:09,398
the loop back address
12058
08:44:10,378 --> 08:44:11,378
as far as for the subnet mask remember
12059
08:44:12,780 --> 08:44:13,780
that all ones have to be continuous from
12060
08:44:15,180 --> 08:44:16,180
the left
12061
08:44:16,200 --> 08:44:17,200
and zeros have to be continuous from the
12062
08:44:18,240 --> 08:44:19,240
right
12063
08:44:19,260 --> 08:44:20,260
our defaults our 255.255.0.0.0
12064
08:44:24,540 --> 08:44:25,540
and then 255
12065
08:44:26,940 --> 08:44:27,940
I'm sorry I think I just said
12066
08:44:29,000 --> 08:44:30,000
255.0.0.0
12067
08:44:31,520 --> 08:44:32,520
285.255.0.0.0 and
12068
08:44:37,160 --> 08:44:38,160
255.255.255.0 those are our defaults and
12069
08:44:40,020 --> 08:44:41,020
so we talked about applying a subnet
12070
08:44:42,298 --> 08:44:43,298
mask using something called anding
12071
08:44:45,718 --> 08:44:46,718
and we looked at how that divides up
12072
08:44:47,760 --> 08:44:48,760
again the network ID from the node ID
12073
08:44:50,398 --> 08:44:51,398
and we saw that in practice finally we
12074
08:44:52,740 --> 08:44:53,740
talked very briefly about custom subnet
12075
08:44:54,958 --> 08:44:55,958
masks something that we don't have to
12076
08:44:56,280 --> 08:44:57,280
get very much into but we talked about
12077
08:44:58,740 --> 08:44:59,740
how if we had 255.255
12078
08:45:03,740 --> 08:45:04,740
.255 dot for instance 128 we could have
12079
08:45:08,580 --> 08:45:09,580
these sort of sub subnets or these uh we
12080
08:45:12,540 --> 08:45:13,540
could break it down even further and
12081
08:45:14,280 --> 08:45:15,280
therefore we could start to do a lot
12082
08:45:16,260 --> 08:45:17,260
more stuff and in the next module I'm
12083
08:45:18,120 --> 08:45:19,120
going to talk about this in a lot more
12084
08:45:19,740 --> 08:45:20,740
detail and why we would want to do it
12085
08:45:25,600 --> 08:45:26,600
[Music]
12086
08:45:34,218 --> 08:45:35,218
thank you
12087
08:45:45,718 --> 08:45:46,718
Network routing and IP addressing
12088
08:45:48,620 --> 08:45:49,620
default and custom addressing
12089
08:45:52,320 --> 08:45:53,320
so we described in the previous module
12090
08:45:54,718 --> 08:45:55,718
subnetting how to determine the network
12091
08:45:57,298 --> 08:45:58,298
from the node ID and we talked
12092
08:45:59,820 --> 08:46:00,820
specifically about ipv4 and we're going
12093
08:46:02,160 --> 08:46:03,160
to continue talking about ipv4 a little
12094
08:46:04,378 --> 08:46:05,378
bit more first by defining the default
12095
08:46:08,600 --> 08:46:09,600
ipv4 addressing scheme now some of this
12096
08:46:11,878 --> 08:46:12,878
we sort of touched on in the previous
12097
08:46:13,200 --> 08:46:14,200
module and some of the stuff we're going
12098
08:46:15,120 --> 08:46:16,120
to talk about right now is going to
12099
08:46:17,700 --> 08:46:18,700
probably help clarify that and so it
12100
08:46:19,740 --> 08:46:20,740
might not it might even help to go back
12101
08:46:21,420 --> 08:46:22,420
and watch the previous module after
12102
08:46:23,458 --> 08:46:24,458
watching this one after that we're going
12103
08:46:25,500 --> 08:46:26,500
to talk about the reserved or restricted
12104
08:46:28,080 --> 08:46:29,080
ipv4 addresses one of the ones we've
12105
08:46:31,798 --> 08:46:32,798
already mentioned is what we called the
12106
08:46:34,138 --> 08:46:35,138
loop back or
12107
08:46:36,440 --> 08:46:37,440
127.0.0.1 that's an example of a
12108
08:46:39,240 --> 08:46:40,240
reserved IP address a restricted IP
12109
08:46:41,638 --> 08:46:42,638
address and so we're going to talk about
12110
08:46:43,020 --> 08:46:44,020
those in more depth and some of the ones
12111
08:46:45,420 --> 08:46:46,420
that some of the ranges that are
12112
08:46:46,978 --> 08:46:47,978
restricted and why they are then we're
12113
08:46:49,558 --> 08:46:50,558
going to discuss what are called the
12114
08:46:51,718 --> 08:46:52,718
private address addresses and we're
12115
08:46:54,180 --> 08:46:55,180
gonna talk about these specifically
12116
08:46:56,398 --> 08:46:57,398
because these are different from public
12117
08:46:58,080 --> 08:46:59,080
IP addresses uh one you might be
12118
08:47:00,360 --> 08:47:01,360
familiar with is the
12119
08:47:02,120 --> 08:47:03,120
192.168 uh public at a private addresses
12120
08:47:05,760 --> 08:47:06,760
rather and you'll this is going to
12121
08:47:07,378 --> 08:47:08,378
explain why every router that you
12122
08:47:09,420 --> 08:47:10,420
purchase that you know electronics store
12123
08:47:11,398 --> 08:47:12,398
has this as its default not everyone but
12124
08:47:14,340 --> 08:47:15,340
a lot of them have this is the default
12125
08:47:15,780 --> 08:47:16,780
IP address and yet we talked about how
12126
08:47:17,638 --> 08:47:18,638
you can't have more than one IP address
12127
08:47:19,200 --> 08:47:20,200
with any device and so we're going to
12128
08:47:20,940 --> 08:47:21,940
describe why with private IP addresses
12129
08:47:23,398 --> 08:47:24,398
this is the case and we'll talk about
12130
08:47:24,718 --> 08:47:25,718
some other private IP addresses as well
12131
08:47:26,638 --> 08:47:27,638
now we're going to talk about the ipv4
12132
08:47:29,840 --> 08:47:30,840
formulas and that's the that's what
12133
08:47:32,398 --> 08:47:33,398
allows us to determine how many
12134
08:47:37,020 --> 08:47:38,020
hosts
12135
08:47:39,298 --> 08:47:40,298
and networks are permissible based on
12136
08:47:43,378 --> 08:47:44,378
the type of IP address the class that
12137
08:47:46,080 --> 08:47:47,080
it's in and the subnet mask that's
12138
08:47:48,420 --> 08:47:49,420
supplied and this will help us also
12139
08:47:50,520 --> 08:47:51,520
determine and talk about in a second uh
12140
08:47:53,100 --> 08:47:54,100
why we might want to use custom subnet
12141
08:47:55,378 --> 08:47:56,378
masks and custom IP addresses
12142
08:47:57,898 --> 08:47:58,898
so then we're going to talk about the
12143
08:47:59,398 --> 08:48:00,398
default gateway is this gets back to
12144
08:48:01,860 --> 08:48:02,860
actually this right here it is the
12145
08:48:04,200 --> 08:48:05,200
device which the any node needs to know
12146
08:48:08,700 --> 08:48:09,700
in order to get out to the network and
12147
08:48:10,320 --> 08:48:11,320
to the rest of the um the rest of the
12148
08:48:12,780 --> 08:48:13,780
world
12149
08:48:14,040 --> 08:48:15,040
finally we're going to talk about custom
12150
08:48:16,920 --> 08:48:17,920
IP address schemes
12151
08:48:19,040 --> 08:48:20,040
vlsm and cidr these are a little more in
12152
08:48:24,000 --> 08:48:25,000
depth but these really get back to the
12153
08:48:25,798 --> 08:48:26,798
subnet masks and why we can apply those
12154
08:48:28,680 --> 08:48:29,680
uh how we can apply sort of specific
12155
08:48:31,200 --> 08:48:32,200
subnet masks to things and we'll look at
12156
08:48:33,420 --> 08:48:34,420
this thing which you might have seen
12157
08:48:34,740 --> 08:48:35,740
cidr which is has to do with why there
12158
08:48:37,378 --> 08:48:38,378
might be a slash after an IP address
12159
08:48:39,478 --> 08:48:40,478
which really gets to the number of bits
12160
08:48:41,458 --> 08:48:42,458
it has and we'll talk about that just a
12161
08:48:43,080 --> 08:48:44,080
minute now aside from being an aspect
12162
08:48:45,000 --> 08:48:46,000
that's covered in many areas of the
12163
08:48:47,160 --> 08:48:48,160
network plus exam understanding the
12164
08:48:49,920 --> 08:48:50,920
classes in a default IP address scheme
12165
08:48:52,320 --> 08:48:53,320
is really important for us and this gets
12166
08:48:54,780 --> 08:48:55,780
back to uh right here so let's talk
12167
08:48:57,360 --> 08:48:58,360
about remember we talked about class
12168
08:48:58,680 --> 08:48:59,680
lesson class full we're going to talk
12169
08:49:00,360 --> 08:49:01,360
about the classes that exist in an IP
12170
08:49:03,420 --> 08:49:04,420
address right now so as we learned in
12171
08:49:06,120 --> 08:49:07,120
previous modules the ipv4 addressing
12172
08:49:09,298 --> 08:49:10,298
scheme is again 32 bits broken up into
12173
08:49:13,978 --> 08:49:14,978
four octets and each octet can range
12174
08:49:17,878 --> 08:49:18,878
from 0 to 255.
12175
08:49:20,340 --> 08:49:21,340
now the international standards
12176
08:49:22,320 --> 08:49:23,320
organization icann which we've mentioned
12177
08:49:25,378 --> 08:49:26,378
in a previous module is in control of
12178
08:49:27,780 --> 08:49:28,780
how these IP addresses are leased and
12179
08:49:30,540 --> 08:49:31,540
distributed out to individuals and
12180
08:49:32,580 --> 08:49:33,580
companies around the world now because
12181
08:49:34,440 --> 08:49:35,440
of the limited amount of IP addresses
12182
08:49:36,958 --> 08:49:37,958
the default ipv4 addressing scheme is
12183
08:49:41,040 --> 08:49:42,040
designed and outlined which what are
12184
08:49:42,958 --> 08:49:43,958
called classes and there are five of
12185
08:49:45,718 --> 08:49:46,718
them that we need to know now these
12186
08:49:47,580 --> 08:49:48,580
classes are identified as a b c d and e
12187
08:49:50,940 --> 08:49:51,940
and each class is designed to facilitate
12188
08:49:54,120 --> 08:49:55,120
in the distribution of IP addresses for
12189
08:49:57,120 --> 08:49:58,120
certain types of purposes now the First
12190
08:49:59,398 --> 08:50:00,398
Class A Class A allows you to have is
12191
08:50:02,940 --> 08:50:03,940
designed for really large Networks
12192
08:50:05,878 --> 08:50:06,878
meaning that it does not have a lot of
12193
08:50:08,878 --> 08:50:09,878
networks because we only have a few of
12194
08:50:10,978 --> 08:50:11,978
them and that is because a Class A Range
12195
08:50:13,920 --> 08:50:14,920
goes from one
12196
08:50:16,080 --> 08:50:17,080
to 127.
12197
08:50:18,478 --> 08:50:19,478
in the
12198
08:50:21,120 --> 08:50:22,120
first
12199
08:50:22,740 --> 08:50:23,740
octet meaning that the remaining octets
12200
08:50:27,000 --> 08:50:28,000
are reserved for nodes and so we see
12201
08:50:29,700 --> 08:50:30,700
that we don't have a lot of networks we
12202
08:50:32,458 --> 08:50:33,458
only have 126 networks one to 127.
12203
08:50:37,260 --> 08:50:38,260
but we do have up to 16
12204
08:50:42,020 --> 08:50:43,020
.7 or 0.8 around about million net I
12205
08:50:47,100 --> 08:50:48,100
nodes that can be on
12206
08:50:49,798 --> 08:50:50,798
this network and so uh we have so many
12207
08:50:52,860 --> 08:50:53,860
nodes for so few uh networks and so this
12208
08:50:56,398 --> 08:50:57,398
is really for very large large networks
12209
08:50:59,280 --> 08:51:00,280
and there are some specifically reserved
12210
08:51:01,978 --> 08:51:02,978
addresses in this as well we'll talk
12211
08:51:03,840 --> 08:51:04,840
about those in just a minute now with
12212
08:51:05,760 --> 08:51:06,760
class B here we have
12213
08:51:08,420 --> 08:51:09,420
128 to 191.
12214
08:51:11,940 --> 08:51:12,940
and these are called Class B they allow
12215
08:51:14,160 --> 08:51:15,160
for a lot more Networks
12216
08:51:17,280 --> 08:51:18,280
and fewer nodes which makes sense
12217
08:51:21,780 --> 08:51:22,780
Now the default subnet mask for class A
12218
08:51:25,860 --> 08:51:26,860
which might make this a little clearer
12219
08:51:30,740 --> 08:51:31,740
255.0.0.0 whereas for a class B it's
12220
08:51:36,798 --> 08:51:37,798
255.255.0.0 now as you can tell the
12221
08:51:39,660 --> 08:51:40,660
class is actually determined by the very
12222
08:51:41,340 --> 08:51:42,340
first octet the number in the first
12223
08:51:43,260 --> 08:51:44,260
octet
12224
08:51:44,458 --> 08:51:45,458
and it's important to then therefore
12225
08:51:46,378 --> 08:51:47,378
memorize these numbers because you'll
12226
08:51:48,718 --> 08:51:49,718
see on your exam they'll ask you which
12227
08:51:50,940 --> 08:51:51,940
class is this IP address a part of if
12228
08:51:53,580 --> 08:51:54,580
it's between 1 and 127 you know it's a
12229
08:51:55,680 --> 08:51:56,680
Class A if it's between 128 and 191 you
12230
08:51:59,040 --> 08:52:00,040
know it's a Class B if we get to a class
12231
08:52:01,138 --> 08:52:02,138
C now we have a lot of networks and not
12232
08:52:04,558 --> 08:52:05,558
a lot of nodes and you can see that
12233
08:52:06,958 --> 08:52:07,958
these are 192 to 223 in the first
12234
08:52:12,138 --> 08:52:13,138
octet and the default subnet mask
12235
08:52:15,840 --> 08:52:16,840
for this is going to be 255 to
12236
08:52:19,580 --> 08:52:20,580
255.255.0 and if you remember that gives
12237
08:52:22,500 --> 08:52:23,500
us only this octet for nodes and all of
12238
08:52:25,318 --> 08:52:26,318
these octets for networks this is
12239
08:52:28,440 --> 08:52:29,440
usually one of the most recognizable for
12240
08:52:30,360 --> 08:52:31,360
home networks because we have the
12241
08:52:35,058 --> 08:52:36,058
192.168.0.1 for instance that is going
12242
08:52:38,100 --> 08:52:39,100
to obviously fall into this class C now
12243
08:52:40,740 --> 08:52:41,740
there are two other classes they're not
12244
08:52:42,120 --> 08:52:43,120
very common but they're important to be
12245
08:52:43,558 --> 08:52:44,558
able to recognize they're a Class D i p
12246
08:52:47,340 --> 08:52:48,340
addresses which are only used for what
12247
08:52:49,020 --> 08:52:50,020
we call multicast Transmissions
12248
08:52:53,218 --> 08:52:54,218
and these are for special routers that
12249
08:52:55,680 --> 08:52:56,680
are able to support the use of IP
12250
08:52:57,660 --> 08:52:58,660
addresses within this range you don't
12251
08:52:59,520 --> 08:53:00,520
really need to worry about this for much
12252
08:53:00,958 --> 08:53:01,958
application unless you're dealing with a
12253
08:53:03,058 --> 08:53:04,058
lot more advanced stuff and these deal
12254
08:53:05,458 --> 08:53:06,458
with 224 to 239
12255
08:53:08,340 --> 08:53:09,340
finally we have class E which is from
12256
08:53:10,860 --> 08:53:11,860
240 to 255 and these are really for
12257
08:53:15,860 --> 08:53:16,860
experimental reasons so we're really not
12258
08:53:18,718 --> 08:53:19,718
going to see these in much play the ones
12259
08:53:21,540 --> 08:53:22,540
you really want to be familiar with
12260
08:53:24,058 --> 08:53:25,058
are these first three classes a b and c
12261
08:53:27,718 --> 08:53:28,718
remember 1 to 127 is a class A 128 to
12262
08:53:34,020 --> 08:53:35,020
191 is a Class B 192 to 223 is a Class C
12263
08:53:40,740 --> 08:53:41,740
if you can remember those ranges I would
12264
08:53:42,660 --> 08:53:43,660
commit them to Memory you'll be good to
12265
08:53:44,160 --> 08:53:45,160
go for the exam now within each of these
12266
08:53:46,318 --> 08:53:47,318
classes there are a number of addresses
12267
08:53:49,318 --> 08:53:50,318
that are not allowed to be assigned or
12268
08:53:51,780 --> 08:53:52,780
leased for specific reasons these are
12269
08:53:53,760 --> 08:53:54,760
what we call reserved and restricted IP
12270
08:53:55,740 --> 08:53:56,740
addresses now we've mentioned the
12271
08:53:58,398 --> 08:53:59,398
127.0.0.1 or the local loopback or the
12272
08:54:01,860 --> 08:54:02,860
localhost i p address before which can't
12273
08:54:04,620 --> 08:54:05,620
be assigned because it's reserved for me
12274
08:54:07,080 --> 08:54:08,080
for myself from for I this means that
12275
08:54:09,660 --> 08:54:10,660
this address is used when I want to
12276
08:54:11,940 --> 08:54:12,940
address myself
12277
08:54:13,740 --> 08:54:14,740
so if I wanted to for instance assign
12278
08:54:16,500 --> 08:54:17,500
myself my own name via DNS and my name
12279
08:54:20,458 --> 08:54:21,458
was me
12280
08:54:22,020 --> 08:54:23,020
me would link up to the IP address
12281
08:54:25,520 --> 08:54:26,520
127.0.0.1 and that way it's going back
12282
08:54:28,020 --> 08:54:29,020
to myself now we're really going to use
12283
08:54:29,520 --> 08:54:30,520
this for mostly diagnostic purposes if I
12284
08:54:32,818 --> 08:54:33,818
want to double check to make sure for
12285
08:54:34,318 --> 08:54:35,318
instance that tcpip is running correctly
12286
08:54:37,100 --> 08:54:38,100
and it's also going to be used for
12287
08:54:39,058 --> 08:54:40,058
programmers and such like that now the
12288
08:54:41,818 --> 08:54:42,818
address
12289
08:54:44,478 --> 08:54:45,478
10.0.0.0 is also restricted and it's not
12290
08:54:47,580 --> 08:54:48,580
available to use because again this a
12291
08:54:50,218 --> 08:54:51,218
host address can never have all zeros
12292
08:54:54,420 --> 08:54:55,420
conversely the addresses that have all
12293
08:54:57,298 --> 08:54:58,298
ones for instance
12294
08:55:03,920 --> 08:55:04,920
255.255.255.255 cannot be used for
12295
08:55:08,520 --> 08:55:09,520
um uh addresses obviously this one can't
12296
08:55:11,818 --> 08:55:12,818
because it would sort of
12297
08:55:13,458 --> 08:55:14,458
ruin the use of a subnet mask but even
12298
08:55:16,080 --> 08:55:17,080
if I had something like
12299
08:55:19,340 --> 08:55:20,340
192.168.0.255 I can't use that because
12300
08:55:21,660 --> 08:55:22,660
that's what's called a broadcast address
12301
08:55:24,420 --> 08:55:25,420
and so it's just simply reserved for
12302
08:55:27,240 --> 08:55:28,240
that this means that if a message is
12303
08:55:29,458 --> 08:55:30,458
transmitted to a network address with
12304
08:55:31,620 --> 08:55:32,620
all ones in the host portion or 255 that
12305
08:55:34,740 --> 08:55:35,740
message is going to be transmitted to
12306
08:55:36,420 --> 08:55:37,420
every single device on the subnet it's
12307
08:55:38,940 --> 08:55:39,940
called a broadcast and we talked about
12308
08:55:40,860 --> 08:55:41,860
broadcast before finally the address
12309
08:55:44,420 --> 08:55:45,420
1.1.1.1 cannot be used because this is
12310
08:55:48,000 --> 08:55:49,000
what's called the all hosts or the who
12311
08:55:50,520 --> 08:55:51,520
is address so these basically what
12312
08:55:54,360 --> 08:55:55,360
whereas 127 is for me
12313
08:55:56,958 --> 08:55:57,958
1.1.1.1 is for everyone so these we can
12314
08:56:00,298 --> 08:56:01,298
never use the important one I really
12315
08:56:01,978 --> 08:56:02,978
want you to remember here is this one
12316
08:56:04,138 --> 08:56:05,138
and you're going to want to remember
12317
08:56:05,398 --> 08:56:06,398
that for instance 255 in the host
12318
08:56:08,340 --> 08:56:09,340
portion can never be used again not only
12319
08:56:11,398 --> 08:56:12,398
because that's going to ruin a subnet as
12320
08:56:13,378 --> 08:56:14,378
we've talked about but also this is
12321
08:56:15,360 --> 08:56:16,360
reserved for what's called a broadcast
12322
08:56:17,040 --> 08:56:18,040
address now there are portions of each
12323
08:56:20,218 --> 08:56:21,218
class that are allocated either for
12324
08:56:23,040 --> 08:56:24,040
public or private use private IP
12325
08:56:25,680 --> 08:56:26,680
addresses are not routable
12326
08:56:28,860 --> 08:56:29,860
this means
12327
08:56:31,080 --> 08:56:32,080
that they are assigned for use on
12328
08:56:33,318 --> 08:56:34,318
internal networks such as your home
12329
08:56:35,580 --> 08:56:36,580
network or your office Network when
12330
08:56:38,398 --> 08:56:39,398
these addresses transmit data and it
12331
08:56:40,500 --> 08:56:41,500
reaches a router the router is not going
12332
08:56:43,740 --> 08:56:44,740
to uh route it outside of the network so
12333
08:56:47,340 --> 08:56:48,340
these addresses can be used without
12334
08:56:49,260 --> 08:56:50,260
needing to purchase or leasing an IP
12335
08:56:51,718 --> 08:56:52,718
address from your ISP or Internet
12336
08:56:53,458 --> 08:56:54,458
service provider or governing entity so
12337
08:56:56,160 --> 08:56:57,160
this is how I could create an internal
12338
08:56:57,780 --> 08:56:58,780
Network in my home and I don't need to
12339
08:57:00,420 --> 08:57:01,420
go register it and I might not be able
12340
08:57:03,000 --> 08:57:04,000
to access the internet but I don't need
12341
08:57:04,260 --> 08:57:05,260
to register if I want to go out to the
12342
08:57:05,940 --> 08:57:06,940
internet then I can share using devices
12343
08:57:09,120 --> 08:57:10,120
and resources we've talked about
12344
08:57:11,700 --> 08:57:12,700
previously and we'll talk about later a
12345
08:57:13,558 --> 08:57:14,558
public IP address with all the internal
12346
08:57:16,138 --> 08:57:17,138
devices that are configured using
12347
08:57:18,120 --> 08:57:19,120
private IP addresses now since these are
12348
08:57:20,818 --> 08:57:21,818
not able to be used externally to our
12349
08:57:23,340 --> 08:57:24,340
Network these IP addresses can be used
12350
08:57:26,100 --> 08:57:27,100
by as many devices as necessary as long
12351
08:57:29,040 --> 08:57:30,040
as we never double over one IP address
12352
08:57:30,958 --> 08:57:31,958
per device so the class a private IP
12353
08:57:34,978 --> 08:57:35,978
address range remember we talked about
12354
08:57:37,160 --> 08:57:38,160
10.0.0.0 because we cannot have zeros
12355
08:57:40,978 --> 08:57:41,978
right remember 10.0.0 and 285 we
12356
08:57:44,218 --> 08:57:45,218
actually cannot assign but any address
12357
08:57:46,620 --> 08:57:47,620
in between that so
12358
08:57:51,798 --> 08:57:52,798
10.1.126.5 would fall into what's called
12359
08:57:55,020 --> 08:57:56,020
a private address range and you might
12360
08:57:57,180 --> 08:57:58,180
see this in your home router as well so
12361
08:57:59,700 --> 08:58:00,700
this makes it easily discernible from
12362
08:58:01,558 --> 08:58:02,558
other addresses in its class anything
12363
08:58:04,020 --> 08:58:05,020
that has the 10 to begin with cannot be
12364
08:58:06,718 --> 08:58:07,718
used on a Class A Network or any network
12365
08:58:08,760 --> 08:58:09,760
except privately
12366
08:58:10,440 --> 08:58:11,440
we also have a class B uh Private
12367
08:58:13,378 --> 08:58:14,378
Exchange which is
12368
08:58:16,398 --> 08:58:17,398
172.16.0.0 through
12369
08:58:20,000 --> 08:58:21,000
172.31.255.255 and Class C which is
12370
08:58:24,558 --> 08:58:25,558
192.168.0.0 through the 255 to 255. this
12371
08:58:28,080 --> 08:58:29,080
one you might have seen the most this
12372
08:58:30,000 --> 08:58:31,000
one I'm guessing you've seen the last
12373
08:58:31,440 --> 08:58:32,440
this one's probably the second most
12374
08:58:33,420 --> 08:58:34,420
common the 10 dot so if you have a
12375
08:58:36,058 --> 08:58:37,058
internal Network at your home you might
12376
08:58:38,520 --> 08:58:39,520
have your address on your computer right
12377
08:58:40,620 --> 08:58:41,620
now for instance if it's not connected
12378
08:58:42,058 --> 08:58:43,058
directly to the network if it's
12379
08:58:43,080 --> 08:58:44,080
connected to a router might be something
12380
08:58:44,958 --> 08:58:45,958
like this or like
12381
08:58:49,138 --> 08:58:50,138
this or even
12382
08:58:53,638 --> 08:58:54,638
like this all right that's because these
12383
08:58:56,160 --> 08:58:57,160
are each private addresses it's
12384
08:58:57,958 --> 08:58:58,958
important that you commit these to
12385
08:58:59,638 --> 08:59:00,638
memory as well because these will appear
12386
08:59:02,280 --> 08:59:03,280
on the exam and remember the important
12387
08:59:04,080 --> 08:59:05,080
thing with a uh
12388
08:59:06,240 --> 08:59:07,240
with a private IP address as I mentioned
12389
08:59:08,458 --> 08:59:09,458
right here is they're not routable and I
12390
08:59:10,020 --> 08:59:11,020
don't need a lease to use them so when
12391
08:59:12,058 --> 08:59:13,058
tasked with subnetting a network you
12392
08:59:13,740 --> 08:59:14,740
need to understand how to calculate how
12393
08:59:15,540 --> 08:59:16,540
many hosts and how many networks are
12394
08:59:17,638 --> 08:59:18,638
available if we want to determine the
12395
08:59:19,440 --> 08:59:20,440
number of hosts that are available we
12396
08:59:21,898 --> 08:59:22,898
apply this Formula 2 to the x minus 2.
12397
08:59:25,500 --> 08:59:26,500
and this is where X
12398
08:59:29,940 --> 08:59:30,940
equals the number of node bits and
12399
08:59:33,240 --> 08:59:34,240
that's after we break it down from
12400
08:59:35,398 --> 08:59:36,398
decimal to binary
12401
08:59:38,218 --> 08:59:39,218
now the reason for the minus 2 here
12402
08:59:42,718 --> 08:59:43,718
is because again we cannot use a DOT
12403
08:59:45,180 --> 08:59:46,180
0.0.0 address or
12404
08:59:49,520 --> 08:59:50,520
a.255.255.255 address which would mean
12405
08:59:52,080 --> 08:59:53,080
all zeros are all ones in the subnet and
12406
08:59:55,440 --> 08:59:56,440
so we need to make sure uh rather in the
12407
08:59:58,500 --> 08:59:59,500
um uh in the bit right when it's broken
12408
09:00:00,718 --> 09:00:01,718
down and so we need to make sure that
12409
09:00:04,020 --> 09:00:05,020
um this is the case
12410
09:00:06,860 --> 09:00:07,860
we also need to know the number of
12411
09:00:09,540 --> 09:00:10,540
networks and to do that we're going to
12412
09:00:11,760 --> 09:00:12,760
do 2 to the Y minus 2 where y equals the
12413
09:00:14,700 --> 09:00:15,700
number of network bits so let's take a
12414
09:00:17,940 --> 09:00:18,940
look at this if we have the IP address
12415
09:00:23,958 --> 09:00:24,958
162.85.120.27 and we have a subnet mask
12416
09:00:26,280 --> 09:00:27,280
of
12417
09:00:27,680 --> 09:00:28,680
255.255.255.0 by the way
12418
09:00:30,540 --> 09:00:31,540
we can look at this and we automatically
12419
09:00:32,218 --> 09:00:33,218
know that
12420
09:00:34,700 --> 09:00:35,700
162.85.120.27 this looks like a class
12421
09:00:38,298 --> 09:00:39,298
b i p address and the 255 the 255 to 255
12422
09:00:42,718 --> 09:00:43,718
is actually our default Class C subnet
12423
09:00:46,440 --> 09:00:47,440
so this is not the default that we're
12424
09:00:48,058 --> 09:00:49,058
working with here so we need to figure
12425
09:00:49,978 --> 09:00:50,978
out uh some information here so let's
12426
09:00:52,378 --> 09:00:53,378
break it down into bits and I'm do that
12427
09:00:54,298 --> 09:00:55,298
here and if you wanted to check my math
12428
09:00:55,558 --> 09:00:56,558
you could now the number of network bits
12429
09:00:58,138 --> 09:00:59,138
is right here the Y and the number of
12430
09:01:00,718 --> 09:01:01,718
node bits is right here
12431
09:01:02,700 --> 09:01:03,700
the X so if we pop this into our
12432
09:01:06,298 --> 09:01:07,298
equation the number of possible hosts we
12433
09:01:08,878 --> 09:01:09,878
have is 254 and the number of possible
12434
09:01:11,878 --> 09:01:12,878
networks is over 16 million if we go
12435
09:01:14,580 --> 09:01:15,580
back to that table we saw a few slides
12436
09:01:16,378 --> 09:01:17,378
ago we'd see then that that's why we
12437
09:01:19,080 --> 09:01:20,080
have a default for class B and Class C
12438
09:01:21,840 --> 09:01:22,840
networks is we can see how many networks
12439
09:01:25,020 --> 09:01:26,020
are possible and how many hosts are
12440
09:01:26,520 --> 09:01:27,520
possible now why would I want to know
12441
09:01:28,558 --> 09:01:29,558
this well let's say that I have to
12442
09:01:31,020 --> 09:01:32,020
divide up my network and I want to have
12443
09:01:32,878 --> 09:01:33,878
a certain number of networks in a
12444
09:01:34,500 --> 09:01:35,500
certain number of hosts well if I only
12445
09:01:36,718 --> 09:01:37,718
need five networks but I need 30 000
12446
09:01:39,600 --> 09:01:40,600
hosts I'm going to be in major trouble
12447
09:01:41,700 --> 09:01:42,700
here because now I have to divide this
12448
09:01:43,378 --> 09:01:44,378
up so much I'm wasting a lot of networks
12449
09:01:45,058 --> 09:01:46,058
and I don't have enough hosts so we want
12450
09:01:47,040 --> 09:01:48,040
to determine how we can do this to
12451
09:01:48,540 --> 09:01:49,540
reduce the amount of waste we're going
12452
09:01:50,580 --> 09:01:51,580
to talk about that in just a bit
12453
09:01:52,558 --> 09:01:53,558
going back to something called a default
12454
09:01:54,360 --> 09:01:55,360
gateway for a second
12455
09:01:56,940 --> 09:01:57,940
device that wants to connect to the
12456
09:01:59,040 --> 09:02:00,040
internet has to go through what's called
12457
09:02:01,318 --> 09:02:02,318
a default gateway this is not a physical
12458
09:02:03,780 --> 09:02:04,780
device this is set by our IP address
12459
09:02:06,540 --> 09:02:07,540
settings it is basically the IP address
12460
09:02:09,180 --> 09:02:10,180
of the device which is usually the
12461
09:02:11,940 --> 09:02:12,940
router or the Border router that's
12462
09:02:14,218 --> 09:02:15,218
connected directly to the to the
12463
09:02:15,780 --> 09:02:16,780
internet for instance we had other
12464
09:02:17,218 --> 09:02:18,218
routers in here
12465
09:02:19,160 --> 09:02:20,160
this is going to be the Gateway
12466
09:02:22,020 --> 09:02:23,020
and so three things need to be
12467
09:02:23,760 --> 09:02:24,760
configured on any device that wants to
12468
09:02:25,440 --> 09:02:26,440
connect to the internet we've talked
12469
09:02:27,000 --> 09:02:28,000
about it we need to have an IP address a
12470
09:02:28,558 --> 09:02:29,558
subnet mask and this is the new one a
12471
09:02:30,660 --> 09:02:31,660
default gateway so this is the device
12472
09:02:33,240 --> 09:02:34,240
that's used when I want to communicate
12473
09:02:35,700 --> 09:02:36,700
with the internet and it's not used when
12474
09:02:38,040 --> 09:02:39,040
communicating with devices on the same
12475
09:02:40,680 --> 09:02:41,680
subnet this is why it's called a Gateway
12476
09:02:43,378 --> 09:02:44,378
think about it as your gateway out to
12477
09:02:45,000 --> 09:02:46,000
the network most often and more often
12478
09:02:47,100 --> 09:02:48,100
than not as I mentioned this is going to
12479
09:02:48,718 --> 09:02:49,718
be the router so if you have at home for
12480
09:02:51,000 --> 09:02:52,000
instance a router that's
12481
09:02:53,298 --> 09:02:54,298
192.168.0.1 that is also your default
12482
09:02:55,920 --> 09:02:56,920
gateway and if you went and did an
12483
09:02:58,500 --> 09:02:59,500
ipconfig all something we'll take a look
12484
09:03:00,420 --> 09:03:01,420
at later and command prompt you'd be
12485
09:03:03,058 --> 09:03:04,058
able to see then your default gateway is
12486
09:03:06,298 --> 09:03:07,298
this address basically it means hey I
12487
09:03:08,100 --> 09:03:09,100
don't know I want to get up to the
12488
09:03:09,420 --> 09:03:10,420
internet I don't know how to get to
12489
09:03:10,378 --> 09:03:11,378
Google I'm going to ask my default
12490
09:03:12,180 --> 09:03:13,180
gateway the default gateway then takes
12491
09:03:14,218 --> 09:03:15,218
care of everything else and then the
12492
09:03:16,318 --> 09:03:17,318
information comes back and it sends it
12493
09:03:18,600 --> 09:03:19,600
out to you again now there are a couple
12494
09:03:20,520 --> 09:03:21,520
different ways of implementing custom IP
12495
09:03:23,280 --> 09:03:24,280
addresses we previously described how we
12496
09:03:25,860 --> 09:03:26,860
could use custom subnets and with that
12497
09:03:28,080 --> 09:03:29,080
method a custom subnet mask and an IP
12498
09:03:31,020 --> 09:03:32,020
address is what we call anded if you
12499
09:03:33,120 --> 09:03:34,120
recall and together they allow the node
12500
09:03:36,298 --> 09:03:37,298
to see the local network as part of its
12501
09:03:38,700 --> 09:03:39,700
larger Network now each customized
12502
09:03:41,280 --> 09:03:42,280
subnet is configured with its own
12503
09:03:43,680 --> 09:03:44,680
default gateway allowing the subnets to
12504
09:03:46,978 --> 09:03:47,978
be able to communicate with each other
12505
09:03:49,378 --> 09:03:50,378
now another method of doing this is
12506
09:03:51,240 --> 09:03:52,240
called vlsm or variable
12507
09:03:57,000 --> 09:03:58,000
length
12508
09:04:00,360 --> 09:04:01,360
subnet
12509
09:04:03,180 --> 09:04:04,180
mask
12510
09:04:05,818 --> 09:04:06,818
and by using this we're going to assign
12511
09:04:08,040 --> 09:04:09,040
each subnet its own separate customized
12512
09:04:11,638 --> 09:04:12,638
subnet mask that varies
12513
09:04:14,160 --> 09:04:15,160
now the VLS MF it allows for a more
12514
09:04:16,920 --> 09:04:17,920
efficient allocation of IP addresses
12515
09:04:19,080 --> 09:04:20,080
with minimal address waste which I was
12516
09:04:21,780 --> 09:04:22,780
just talking about so for example let's
12517
09:04:23,700 --> 09:04:24,700
take a situation in which a network
12518
09:04:26,160 --> 09:04:27,160
administrator wants to have three
12519
09:04:28,020 --> 09:04:29,020
networks and I have a class
12520
09:04:30,360 --> 09:04:31,360
c space
12521
09:04:32,458 --> 09:04:33,458
now just so you know some of this is
12522
09:04:35,718 --> 09:04:36,718
very outdated and we're not going to see
12523
09:04:38,040 --> 09:04:39,040
it used a lot of the time that being
12524
09:04:40,020 --> 09:04:41,020
said Network plus really wants you to
12525
09:04:41,818 --> 09:04:42,818
know about it so we're going to cover it
12526
09:04:43,680 --> 09:04:44,680
so I know I need to have three different
12527
09:04:45,898 --> 09:04:46,898
networks or sub Networks and I know on
12528
09:04:48,240 --> 09:04:49,240
the first Network I want to have four
12529
09:04:50,638 --> 09:04:51,638
hosts on the set network I want to have
12530
09:04:52,318 --> 09:04:53,318
11 hosts and on the third network I want
12531
09:04:54,180 --> 09:04:55,180
to have 27 hosts now in order to
12532
09:04:57,058 --> 09:04:58,058
accomplish this I could use the subnet
12533
09:04:58,978 --> 09:04:59,978
mask
12534
09:04:59,718 --> 09:05:00,718
255.255 the 255.20 that 224.
12535
09:05:03,780 --> 09:05:04,780
and for each of these subnets if I was
12536
09:05:06,478 --> 09:05:07,478
to add this out right one two three four
12537
09:05:09,240 --> 09:05:10,240
five six seven eight that's 255 one two
12538
09:05:12,780 --> 09:05:13,780
three four five six seven eight
12539
09:05:15,660 --> 09:05:16,660
that's 255 one two three four five six
12540
09:05:18,958 --> 09:05:19,958
seven eight that's 255 let's write 224
12541
09:05:22,200 --> 09:05:23,200
in bits all right let's go through our
12542
09:05:24,600 --> 09:05:25,600
calculation again here I'm just going to
12543
09:05:26,638 --> 09:05:27,638
do this because it never hurts
12544
09:05:28,798 --> 09:05:29,798
to do this a couple times
12545
09:05:31,440 --> 09:05:32,440
so let's write all of these out
12546
09:05:39,000 --> 09:05:40,000
great all right we have one two four
12547
09:05:43,440 --> 09:05:44,440
eight sixteen
12548
09:05:46,378 --> 09:05:47,378
32 64 128.
12549
09:05:50,818 --> 09:05:51,818
now we remember that subnet masks have
12550
09:05:53,760 --> 09:05:54,760
to have continuous ones so that's 128
12551
09:05:56,718 --> 09:05:57,718
128 plus 64 is
12552
09:06:00,978 --> 09:06:01,978
192 plus 32
12553
09:06:05,160 --> 09:06:06,160
is 224.
12554
09:06:07,860 --> 09:06:08,860
so then if we broke this down into bits
12555
09:06:10,200 --> 09:06:11,200
this is what it's going to look like
12556
09:06:12,122 --> 09:06:13,122
okay
12557
09:06:13,980 --> 09:06:14,980
so let's write that out here
12558
09:06:21,840 --> 09:06:22,840
and if we do our calculation we know we
12559
09:06:24,540 --> 09:06:25,540
need to have how many hosts when we need
12560
09:06:26,700 --> 09:06:27,700
four so let's do our calculation 2 to
12561
09:06:30,480 --> 09:06:31,480
the 1 2 3 4 5 power
12562
09:06:35,700 --> 09:06:36,700
right
12563
09:06:37,020 --> 09:06:38,020
we're going to figure out how many hosts
12564
09:06:38,700 --> 09:06:39,700
that equals we already know it's 32.
12565
09:06:42,122 --> 09:06:43,122
minus 2 means that we can have
12566
09:06:45,300 --> 09:06:46,300
up to 30 hosts on this subnet
12567
09:06:51,000 --> 09:06:52,000
so I'm wasting an effect 26 addresses on
12568
09:06:55,078 --> 09:06:56,078
this subnet 19 on this one and three on
12569
09:06:58,140 --> 09:06:59,140
this one I'm not really doing a good job
12570
09:07:00,660 --> 09:07:01,660
because I've had to apply the same
12571
09:07:02,520 --> 09:07:03,520
subnet mask
12572
09:07:04,078 --> 09:07:05,078
to every single
12573
09:07:06,540 --> 09:07:07,540
IP address
12574
09:07:08,340 --> 09:07:09,340
and in doing so I'm wasting a lot of my
12575
09:07:10,800 --> 09:07:11,800
possible addresses
12576
09:07:12,782 --> 09:07:13,782
now if I used vlsm instead it's going to
12577
09:07:16,200 --> 09:07:17,200
erase all this
12578
09:07:17,700 --> 09:07:18,700
I could do
12579
09:07:20,598 --> 09:07:21,598
255.255.248.240 and.224. now remember uh
12580
09:07:24,782 --> 09:07:25,782
248
12581
09:07:26,578 --> 09:07:27,578
if we route that out
12582
09:07:28,438 --> 09:07:29,438
I'm just gonna
12583
09:07:30,418 --> 09:07:31,418
really quickly
12584
09:07:53,938 --> 09:07:54,938
all right and you can double check my
12585
09:07:55,738 --> 09:07:56,738
math here
12586
09:07:56,878 --> 09:07:57,878
if we do 248
12587
09:08:00,782 --> 09:08:01,782
that is going to be
12588
09:08:02,758 --> 09:08:03,758
one one one one one one
12589
09:08:06,140 --> 09:08:07,140
zero zero zero
12590
09:08:08,520 --> 09:08:09,520
all right and then if we do our
12591
09:08:09,840 --> 09:08:10,840
calculation two to the 3 because we have
12592
09:08:12,000 --> 09:08:13,000
three host bits
12593
09:08:13,918 --> 09:08:14,918
what does that equal eight minus two
12594
09:08:16,622 --> 09:08:17,622
well now
12595
09:08:18,718 --> 09:08:19,718
we have a possibility of six hosts so
12596
09:08:22,500 --> 09:08:23,500
what is our waste two because six minus
12597
09:08:25,020 --> 09:08:26,020
four equals two a lot better right if we
12598
09:08:28,738 --> 09:08:29,738
do the same thing with uh the next one
12599
09:08:31,438 --> 09:08:32,438
and you were to do the same thing I just
12600
09:08:32,938 --> 09:08:33,938
did that would look one one one one zero
12601
09:08:36,960 --> 09:08:37,960
zero zero zero we did the calculation
12602
09:08:39,540 --> 09:08:40,540
again two to the four because now we
12603
09:08:42,000 --> 09:08:43,000
have four bits
12604
09:08:44,180 --> 09:08:45,180
minus two
12605
09:08:46,020 --> 09:08:47,020
which equals 16 minus two which equals
12606
09:08:49,622 --> 09:08:50,622
fourteen so now I'm only wasting three
12607
09:08:52,558 --> 09:08:53,558
bits because 16
12608
09:08:55,020 --> 09:08:56,020
sorry 14 minus 11 equals three and
12609
09:08:59,040 --> 09:09:00,040
finally 224 is the same remember that
12610
09:09:00,898 --> 09:09:01,898
was 30 bits or 30 hosts rather 30 minus
12611
09:09:04,558 --> 09:09:05,558
27 is 3. so doing this variable
12612
09:09:09,718 --> 09:09:10,718
we are a variable subnet mask we're no
12613
09:09:12,718 --> 09:09:13,718
longer wasting as many host addresses so
12614
09:09:16,860 --> 09:09:17,860
by utilizing this we're going to
12615
09:09:18,598 --> 09:09:19,598
appropriately plan and Implement a
12616
09:09:20,578 --> 09:09:21,578
scheme and it allows us to use our space
12617
09:09:22,918 --> 09:09:23,918
much more effectively of course the
12618
09:09:25,918 --> 09:09:26,918
negative aspect of this is it's a lot
12619
09:09:27,598 --> 09:09:28,598
more harder to scale
12620
09:09:29,398 --> 09:09:30,398
and if I want to add nodes to these
12621
09:09:31,378 --> 09:09:32,378
customized networks I might have to go
12622
09:09:32,700 --> 09:09:33,700
around and change all the subnet masks
12623
09:09:35,040 --> 09:09:36,040
as well now cider which is cidr which
12624
09:09:39,598 --> 09:09:40,598
stands for class less
12625
09:09:43,738 --> 09:09:44,738
enter
12626
09:09:46,258 --> 09:09:47,258
domain
12627
09:09:49,078 --> 09:09:50,078
routing
12628
09:09:51,540 --> 09:09:52,540
is also commonly called super netting
12629
09:09:58,020 --> 09:09:59,020
or classless routing it's another method
12630
09:10:01,738 --> 09:10:02,738
of addressing that uses the vlsm but in
12631
09:10:05,040 --> 09:10:06,040
a different way is at the 32-bit word so
12632
09:10:07,558 --> 09:10:08,558
the notation is much easier to read
12633
09:10:10,378 --> 09:10:11,378
because it combines the IP address
12634
09:10:13,438 --> 09:10:14,438
with this Dash after it
12635
09:10:15,960 --> 09:10:16,960
for instance the number is what denotes
12636
09:10:18,480 --> 09:10:19,480
the amount of ones in the subnet mask
12637
09:10:21,300 --> 09:10:22,300
from left to right so if we look at this
12638
09:10:25,020 --> 09:10:26,020
notation right here we have
12639
09:10:29,122 --> 09:10:30,122
192.168.13.0.23 well the 23 means there
12640
09:10:31,860 --> 09:10:32,860
are 23 ones from left to right in the
12641
09:10:34,860 --> 09:10:35,860
subnet mask
12642
09:10:36,418 --> 09:10:37,418
okay and now if we were to convert that
12643
09:10:39,418 --> 09:10:40,418
this allows for a possible amount of
12644
09:10:41,700 --> 09:10:42,700
host addresses 2 to the ninth
12645
09:10:46,918 --> 09:10:47,918
minus two
12646
09:10:48,782 --> 09:10:49,782
which equals 500
12647
09:10:51,480 --> 09:10:52,480
and 10 addresses so this allows for more
12648
09:10:55,200 --> 09:10:56,200
than one class full Network to be
12649
09:10:57,782 --> 09:10:58,782
represented by a single set basically we
12650
09:11:01,020 --> 09:11:02,020
can now break it up further into smaller
12651
09:11:02,820 --> 09:11:03,820
sub networks if we look at three of the
12652
09:11:04,738 --> 09:11:05,738
most easily recognizable ones I'm just
12653
09:11:07,500 --> 09:11:08,500
going to erase this so we can get a
12654
09:11:08,520 --> 09:11:09,520
better look here uh the slash eight
12655
09:11:12,300 --> 09:11:13,300
the slash 16 and the slash 24
12656
09:11:16,020 --> 09:11:17,020
we can see that these translate
12657
09:11:17,520 --> 09:11:18,520
basically over to the basic Class A
12658
09:11:21,000 --> 09:11:22,000
Class B and Class C networks right
12659
09:11:23,160 --> 09:11:24,160
because slash eight Class A that means
12660
09:11:26,282 --> 09:11:27,282
it's one one or one two three four five
12661
09:11:29,640 --> 09:11:30,640
six seven eight dot zero dot zero dot
12662
09:11:34,320 --> 09:11:35,320
zero which would mean
12663
09:11:38,898 --> 09:11:39,898
255.25.0.0.0 which is our default subnet
12664
09:11:41,398 --> 09:11:42,398
mask for Class A
12665
09:11:42,960 --> 09:11:43,960
because again
12666
09:11:45,238 --> 09:11:46,238
this is my network ID is the first octet
12667
09:11:47,820 --> 09:11:48,820
and the node ID are the last ones and
12668
09:11:50,098 --> 09:11:51,098
you can see that that would fall out for
12669
09:11:52,438 --> 09:11:53,438
the next ones as well so because of the
12670
09:11:54,782 --> 09:11:55,782
ease by which it is we can subnet
12671
09:11:57,598 --> 09:11:58,598
networks this way because of readability
12672
09:11:59,820 --> 09:12:00,820
and efficiency cider notation has become
12673
09:12:03,180 --> 09:12:04,180
extremely popular and wider widely
12674
09:12:06,000 --> 09:12:07,000
adopted
12675
09:12:07,020 --> 09:12:08,020
most of the internet in fact has become
12676
09:12:09,480 --> 09:12:10,480
class less address space because of this
12677
09:12:12,660 --> 09:12:13,660
meaning that we don't really use classes
12678
09:12:14,282 --> 09:12:15,282
and we get to IPv6 we're not going to
12679
09:12:16,622 --> 09:12:17,622
see it at all now again this is very
12680
09:12:18,480 --> 09:12:19,480
complex the important thing I just want
12681
09:12:19,918 --> 09:12:20,918
you to remember on this whole thing is
12682
09:12:22,258 --> 09:12:23,258
that if you see this Dash after
12683
09:12:26,878 --> 09:12:27,878
an address here you know exactly what
12684
09:12:31,140 --> 09:12:32,140
the subnet mask is and then you can
12685
09:12:34,140 --> 09:12:35,140
backwards engineer or forward engineer
12686
09:12:36,360 --> 09:12:37,360
the IP address or the network ID or node
12687
09:12:39,540 --> 09:12:40,540
ID
12688
09:12:40,438 --> 09:12:41,438
so just to review some of the points
12689
09:12:42,360 --> 09:12:43,360
that we covered here we started by
12690
09:12:44,460 --> 09:12:45,460
outlining the ipv4 addressing scheme we
12691
09:12:48,180 --> 09:12:49,180
looked at the five classes the three I
12692
09:12:50,098 --> 09:12:51,098
really want you to be aware of are a b
12693
09:12:52,500 --> 09:12:53,500
and c remember a is anything in the
12694
09:12:56,282 --> 09:12:57,282
first octet that's one
12695
09:12:58,980 --> 09:12:59,980
through 127
12696
09:13:01,738 --> 09:13:02,738
with class B we're looking at anything
12697
09:13:04,578 --> 09:13:05,578
from 128
12698
09:13:07,918 --> 09:13:08,918
to 191 and with class C we're looking at
12699
09:13:11,040 --> 09:13:12,040
anything from 191 or rather 192.
12700
09:13:16,980 --> 09:13:17,980
to 223. anything else here we're really
12701
09:13:20,640 --> 09:13:21,640
looking at experimental and stuff that
12702
09:13:23,282 --> 09:13:24,282
we don't really need remember these
12703
09:13:25,320 --> 09:13:26,320
ranges for that first octet it's easy
12704
09:13:27,540 --> 09:13:28,540
then to determine what class we're
12705
09:13:29,700 --> 09:13:30,700
looking at
12706
09:13:30,782 --> 09:13:31,782
okay so we also described the reserved
12707
09:13:33,000 --> 09:13:34,000
or restricted IP addresses for instance
12708
09:13:34,738 --> 09:13:35,738
we can't have anything
12709
09:13:36,960 --> 09:13:37,960
with a zot 0.0.0 or
12710
09:13:40,500 --> 09:13:41,500
with a 255.255.255.
12711
09:13:45,718 --> 09:13:46,718
because these are a multicast addresses
12712
09:13:48,122 --> 09:13:49,122
and we also can't have anything with
12713
09:13:51,438 --> 09:13:52,438
127.0.0.1 ever
12714
09:13:53,398 --> 09:13:54,398
or
12715
09:13:54,918 --> 09:13:55,918
1.1.1.1 because these are both ones the
12716
09:13:58,078 --> 09:13:59,078
localhost one is the who is address
12717
09:14:00,540 --> 09:14:01,540
we then looked at uh private IP
12718
09:14:03,540 --> 09:14:04,540
addresses remember we had three
12719
09:14:05,520 --> 09:14:06,520
different ones each for each class for
12720
09:14:07,622 --> 09:14:08,622
class A it was anything 10.x.x.x
12721
09:14:12,000 --> 09:14:13,000
with class B it was one seven two dot
12722
09:14:16,558 --> 09:14:17,558
sixteen dot x dot X through
12723
09:14:23,540 --> 09:14:24,540
172.31.x.x and the one you're probably
12724
09:14:25,680 --> 09:14:26,680
most familiar with is the class C which
12725
09:14:28,258 --> 09:14:29,258
is 192.168.x.x
12726
09:14:32,340 --> 09:14:33,340
remember that you can see what class
12727
09:14:35,520 --> 09:14:36,520
they're in
12728
09:14:37,258 --> 09:14:38,258
by looking at this and most importantly
12729
09:14:40,140 --> 09:14:41,140
class a private IP address can allow for
12730
09:14:43,078 --> 09:14:44,078
the most networks the fewest I'm sorry
12731
09:14:45,480 --> 09:14:46,480
the most nodes the fewest networks Class
12732
09:14:47,520 --> 09:14:48,520
C is going to be the complete opposite
12733
09:14:48,718 --> 09:14:49,718
I'm going to allow for the most nodes
12734
09:14:51,058 --> 09:14:52,058
the most networks rather but the fewest
12735
09:14:53,398 --> 09:14:54,398
nodes okay and again remember these
12736
09:14:56,878 --> 09:14:57,878
ranges because they will come up what is
12737
09:14:58,918 --> 09:14:59,918
make a private IP address it is not
12738
09:15:01,622 --> 09:15:02,622
routed past a router onto the public
12739
09:15:04,800 --> 09:15:05,800
network okay we also talked about the
12740
09:15:07,460 --> 09:15:08,460
ipv4 formulas which allow us to
12741
09:15:09,718 --> 09:15:10,718
determine
12742
09:15:11,040 --> 09:15:12,040
how many hosts
12743
09:15:12,960 --> 09:15:13,960
or how many networks are allowed on a
12744
09:15:15,660 --> 09:15:16,660
network and that is where the x or the y
12745
09:15:18,122 --> 09:15:19,122
equals the number of hosts or network
12746
09:15:20,098 --> 09:15:21,098
bits we defined the default gateway
12747
09:15:22,918 --> 09:15:23,918
which is what I need
12748
09:15:27,058 --> 09:15:28,058
to get out to the WAN it's what a local
12749
09:15:29,300 --> 09:15:30,300
device a node on the local area network
12750
09:15:31,622 --> 09:15:32,622
needs to go to this default gateway and
12751
09:15:34,320 --> 09:15:35,320
finally we Define the two custom IP
12752
09:15:36,300 --> 09:15:37,300
address schemes the one which allows me
12753
09:15:38,520 --> 09:15:39,520
for variable subnetting and the other
12754
09:15:41,660 --> 09:15:42,660
cider which allows me to
12755
09:15:45,180 --> 09:15:46,180
use a slash and then put a number that
12756
09:15:48,180 --> 09:15:49,180
number representing
12757
09:15:50,340 --> 09:15:51,340
the number of
12758
09:15:52,558 --> 09:15:53,558
Network bits in the subnet mask
12759
09:15:58,078 --> 09:15:59,078
right so the most popular of course 24
12760
09:16:00,660 --> 09:16:01,660
would be for a class C
12761
09:16:03,540 --> 09:16:04,540
16b for a class B and 8 would be for a
12762
09:16:07,378 --> 09:16:08,378
class A because if we had a slash eight
12763
09:16:10,558 --> 09:16:11,558
that would mean the subnet mask is
12764
09:16:12,000 --> 09:16:13,000
255.0.0.0
12765
09:16:17,830 --> 09:16:18,830
[Music]
12766
09:16:25,558 --> 09:16:26,558
foreign
12767
09:16:38,282 --> 09:16:39,282
Network routing and IP addressing
12768
09:16:41,398 --> 09:16:42,398
data delivery techniques and IPv6
12769
09:16:47,700 --> 09:16:48,700
now we've talked a lot about IP
12770
09:16:49,800 --> 09:16:50,800
addressing when it comes to ipv4 or the
12771
09:16:53,218 --> 09:16:54,218
Internet Protocol version 4 but fairly
12772
09:16:56,098 --> 09:16:57,098
recently IPv6 or IP or Internet Protocol
12773
09:16:59,640 --> 09:17:00,640
version 6 was released and has now begun
12774
09:17:02,820 --> 09:17:03,820
to be implemented across the world in
12775
09:17:05,938 --> 09:17:06,938
every Network situation so in this
12776
09:17:09,000 --> 09:17:10,000
module we're going to discuss the Core
12777
09:17:11,758 --> 09:17:12,758
Concepts that are involved with IPv6
12778
09:17:14,700 --> 09:17:15,700
addressing and some of the data delivery
12779
09:17:18,122 --> 09:17:19,122
techniques as well so at the completion
12780
09:17:21,300 --> 09:17:22,300
of this module we're going to have a
12781
09:17:23,520 --> 09:17:24,520
complete understanding of the properties
12782
09:17:26,040 --> 09:17:27,040
of IP version 6 or IPv6
12783
09:17:30,418 --> 09:17:31,418
and we're going to be able to
12784
09:17:31,500 --> 09:17:32,500
differentiate between IPv6 and ipv4
12785
09:17:35,578 --> 09:17:36,578
which is the one we've been talking
12786
09:17:36,898 --> 09:17:37,898
about up into this point as a reminder
12787
09:17:39,180 --> 09:17:40,180
ipv4 is that IP address that is 38-bit
12788
09:17:43,558 --> 09:17:44,558
32 bits and divided into four octets
12789
09:17:48,480 --> 09:17:49,480
and we're also going to outline some of
12790
09:17:50,160 --> 09:17:51,160
the improvements in the mechanisms of
12791
09:17:52,460 --> 09:17:53,460
IPv6 and why we needed to have another
12792
09:17:55,860 --> 09:17:56,860
version of Ip addressing
12793
09:17:58,200 --> 09:17:59,200
we're also going to cover the different
12794
09:17:59,640 --> 09:18:00,640
data delivery techniques as well as what
12795
09:18:03,480 --> 09:18:04,480
a connection is different connection
12796
09:18:05,460 --> 09:18:06,460
modes and we touched on these briefly
12797
09:18:07,320 --> 09:18:08,320
such as connection oriented and
12798
09:18:09,122 --> 09:18:10,122
connection less and they're transmit
12799
09:18:11,520 --> 09:18:12,520
types finally we're going to go further
12800
09:18:14,340 --> 09:18:15,340
into data flow or flow control which
12801
09:18:16,980 --> 09:18:17,980
we've talked about a bit and we've
12802
09:18:18,660 --> 09:18:19,660
mentioned a bit buffering and data
12803
09:18:21,718 --> 09:18:22,718
Windows these are all techniques that
12804
09:18:24,418 --> 09:18:25,418
allow data to be sent over a network in
12805
09:18:28,500 --> 09:18:29,500
varying ways and finally also we're
12806
09:18:31,558 --> 09:18:32,558
going to talk about error detection
12807
09:18:33,660 --> 09:18:34,660
methods that way we know when data
12808
09:18:36,058 --> 09:18:37,058
arrives on the other end we can double
12809
09:18:38,460 --> 09:18:39,460
check it to make sure it is the data
12810
09:18:40,258 --> 09:18:41,258
that was in fact sent
12811
09:18:42,598 --> 09:18:43,598
so in the last module we learned about
12812
09:18:46,200 --> 09:18:47,200
the ipv4 addressing scheme and we talked
12813
09:18:49,558 --> 09:18:50,558
about some aspects of How It's
12814
09:18:51,000 --> 09:18:52,000
implemented now IPv6 is the successor to
12815
09:18:54,660 --> 09:18:55,660
ibv4 and it offers a lot of benefits
12816
09:18:57,000 --> 09:18:58,000
over its predecessor
12817
09:18:58,738 --> 09:18:59,738
the first major Improvement that came
12818
09:19:00,660 --> 09:19:01,660
with this new version is that there's
12819
09:19:02,218 --> 09:19:03,218
been an exponential increase in the
12820
09:19:04,918 --> 09:19:05,918
number of possible addresses that are
12821
09:19:07,800 --> 09:19:08,800
available
12822
09:19:08,660 --> 09:19:09,660
several other features were added to
12823
09:19:11,218 --> 09:19:12,218
this addressing scheme as well such as
12824
09:19:12,840 --> 09:19:13,840
security
12825
09:19:14,120 --> 09:19:15,120
improved composition for what are called
12826
09:19:16,200 --> 09:19:17,200
unicast addresses header simplification
12827
09:19:19,380 --> 09:19:20,380
and how they're sent and a hierarchical
12828
09:19:22,740 --> 09:19:23,740
addressing for what some would suggest
12829
09:19:25,980 --> 09:19:26,980
is easier routing and there's also a
12830
09:19:28,620 --> 09:19:29,620
support for what we call time sensitive
12831
09:19:30,780 --> 09:19:31,780
traffic or traffic that needs to be
12832
09:19:32,700 --> 09:19:33,700
received in a certain amount of time
12833
09:19:34,500 --> 09:19:35,500
such as voice over IP and gaming and
12834
09:19:36,900 --> 09:19:37,900
we're going to look at all this shortly
12835
09:19:38,480 --> 09:19:39,480
so the IPv6 addressing scheme uses a 128
12836
09:19:45,660 --> 09:19:46,660
bit binary address this is different of
12837
09:19:49,080 --> 09:19:50,080
course from ipv4 which again uses a
12838
09:19:53,120 --> 09:19:54,120
32-bit address so this means therefore
12839
09:19:56,820 --> 09:19:57,820
that there are two
12840
09:19:58,916 --> 09:19:59,916
to 128 power possible addresses as
12841
09:20:03,660 --> 09:20:04,660
opposed to 2 to the 32 power with um IP
12842
09:20:07,916 --> 09:20:08,916
address 4.
12843
09:20:09,840 --> 09:20:10,840
and this means therefore that there are
12844
09:20:12,960 --> 09:20:13,960
around
12845
09:20:14,060 --> 09:20:15,060
340
12846
09:20:15,860 --> 09:20:16,860
undecilion I'm going to write that out
12847
09:20:18,300 --> 09:20:19,300
so that's a word that you probably
12848
09:20:19,560 --> 09:20:20,560
haven't seen a lot on
12849
09:20:26,096 --> 09:20:27,096
decillion addresses and to put that
12850
09:20:29,040 --> 09:20:30,040
another way it's enough for one trillion
12851
09:20:32,096 --> 09:20:33,096
people to each have a trillion addresses
12852
09:20:35,596 --> 09:20:36,596
or for an IP address for every single
12853
09:20:38,880 --> 09:20:39,880
grain of sand on the earth times a
12854
09:20:41,936 --> 09:20:42,936
trillion Earths give or take a bit so if
12855
09:20:45,360 --> 09:20:46,360
the 128-bit address were written out in
12856
09:20:48,240 --> 09:20:49,240
binary it would be
12857
09:20:50,416 --> 09:20:51,416
128 ones and zeros because that is
12858
09:20:54,840 --> 09:20:55,840
binary
12859
09:20:56,700 --> 09:20:57,700
and even in decimal form that's a pretty
12860
09:20:59,880 --> 09:21:00,880
hard to read and keep track of so
12861
09:21:02,040 --> 09:21:03,040
because of this we use what's called
12862
09:21:05,300 --> 09:21:06,300
hexadecimal
12863
09:21:07,256 --> 09:21:08,256
as the format in which uh IPv6 is
12864
09:21:11,880 --> 09:21:12,880
written and if you imagine from the name
12865
09:21:14,400 --> 09:21:15,400
hex uh binary is a base 2 system meaning
12866
09:21:19,320 --> 09:21:20,320
that we take everything to the power of
12867
09:21:21,480 --> 09:21:22,480
two so we have the ones place and then
12868
09:21:24,840 --> 09:21:25,840
we have the two place and then we have
12869
09:21:27,240 --> 09:21:28,240
the fourth place and so on and so forth
12870
09:21:30,120 --> 09:21:31,120
with decimal which is a base 10 system
12871
09:21:33,900 --> 09:21:34,900
we have the ones place the tens place
12872
09:21:38,520 --> 09:21:39,520
the hundreds place which is ten times
12873
09:21:40,680 --> 09:21:41,680
ten the thousands place and so on with
12874
09:21:44,040 --> 09:21:45,040
hexadecimal though
12875
09:21:46,140 --> 09:21:47,140
we're looking at a base 16.
12876
09:21:49,436 --> 09:21:50,436
so every single digit
12877
09:21:52,200 --> 09:21:53,200
has a possible 16 different options so
12878
09:21:57,060 --> 09:21:58,060
we'd have a ones place which we always
12879
09:21:59,460 --> 09:22:00,460
start with a ones place and then a 16s
12880
09:22:03,300 --> 09:22:04,300
place and then so on and so forth now
12881
09:22:06,596 --> 09:22:07,596
the way we do this is that every digit
12882
09:22:09,540 --> 09:22:10,540
as opposed to decimal where we have zero
12883
09:22:12,180 --> 09:22:13,180
to nine options for every digit and
12884
09:22:15,480 --> 09:22:16,480
binary where you have either zero or one
12885
09:22:18,060 --> 09:22:19,060
with hexadecimal we can either have zero
12886
09:22:21,416 --> 09:22:22,416
to nine
12887
09:22:22,380 --> 09:22:23,380
or a through F if we add this up we have
12888
09:22:26,220 --> 09:22:27,220
10 options here 0 through 9 and then a
12889
09:22:28,740 --> 09:22:29,740
through F we have six so a hexadecimal
12890
09:22:32,460 --> 09:22:33,460
number is going to be a combination of
12891
09:22:34,380 --> 09:22:35,380
anywhere from 0 to f
12892
09:22:37,080 --> 09:22:38,080
uh a would be 10 B would be 11 C would
12893
09:22:41,580 --> 09:22:42,580
be 12 and so on and so forth so when you
12894
09:22:44,580 --> 09:22:45,580
see uh this written out that's what that
12895
09:22:46,916 --> 09:22:47,916
means okay now the address is broken up
12896
09:22:50,460 --> 09:22:51,460
into eight groups of four hexadecimal
12897
09:22:54,060 --> 09:22:55,060
digits
12898
09:22:55,200 --> 09:22:56,200
and these are separated by colons
12899
09:22:58,080 --> 09:22:59,080
now uh I'm going to show you this in
12900
09:23:00,300 --> 09:23:01,300
just a second but there are also a
12901
09:23:01,860 --> 09:23:02,860
couple of rules when it applies to when
12902
09:23:03,776 --> 09:23:04,776
we come to readability
12903
09:23:05,756 --> 09:23:06,756
so the first rule
12904
09:23:07,916 --> 09:23:08,916
is that let's say this is our
12905
09:23:10,140 --> 09:23:11,140
hexadecimal
12906
09:23:12,860 --> 09:23:13,860
IPv6 address you notice first of all one
12907
09:23:18,300 --> 09:23:19,300
two
12908
09:23:19,740 --> 09:23:20,740
three
12909
09:23:21,180 --> 09:23:22,180
four
12910
09:23:22,916 --> 09:23:23,916
five
12911
09:23:24,540 --> 09:23:25,540
six
12912
09:23:26,040 --> 09:23:27,040
seven
12913
09:23:27,360 --> 09:23:28,360
eight right there are eight groups
12914
09:23:31,200 --> 09:23:32,200
of four hexadecimal digits each
12915
09:23:34,860 --> 09:23:35,860
and of course each one of these digits
12916
09:23:37,200 --> 09:23:38,200
has 16 possible values okay so let's
12917
09:23:40,380 --> 09:23:41,380
look at two rules and these are also not
12918
09:23:42,776 --> 09:23:43,776
only readability rules but what we call
12919
09:23:44,936 --> 09:23:45,936
truncation rules meaning this is how we
12920
09:23:46,916 --> 09:23:47,916
can shorten
12921
09:23:48,360 --> 09:23:49,360
an IPv6 address since they can get quite
12922
09:23:51,360 --> 09:23:52,360
long
12923
09:23:52,256 --> 09:23:53,256
the first rule is that any leading zeros
12924
09:23:55,140 --> 09:23:56,140
can be removed so if we imagine any
12925
09:23:57,840 --> 09:23:58,840
leading zeros I'm going to circle them
12926
09:23:59,936 --> 09:24:00,936
right there
12927
09:24:02,040 --> 09:24:03,040
right here
12928
09:24:05,700 --> 09:24:06,700
right here and if we wanted we could
12929
09:24:08,160 --> 09:24:09,160
even consider these leading zeros
12930
09:24:11,520 --> 09:24:12,520
and therefore if we rewrite this out
12931
09:24:13,680 --> 09:24:14,680
below you'll see we're going to remove
12932
09:24:17,820 --> 09:24:18,820
all the leading zeros
12933
09:24:20,276 --> 09:24:21,276
and that allows us to shorten
12934
09:24:23,460 --> 09:24:24,460
our address
12935
09:24:26,820 --> 09:24:27,820
now we could also
12936
09:24:29,220 --> 09:24:30,220
if I was just going to take this one
12937
09:24:30,900 --> 09:24:31,900
step further
12938
09:24:34,916 --> 09:24:35,916
I could also shorten
12939
09:24:38,700 --> 09:24:39,700
these zeros if I so wished
12940
09:24:42,596 --> 09:24:43,596
and just leave one zero there
12941
09:24:46,980 --> 09:24:47,980
now no matter how you write out
12942
09:24:50,040 --> 09:24:51,040
the address the rules are put in place
12943
09:24:52,560 --> 09:24:53,560
in a way that you can always go back to
12944
09:24:55,320 --> 09:24:56,320
the
12945
09:24:56,820 --> 09:24:57,820
main address and so you don't have to
12946
09:24:59,756 --> 09:25:00,756
worry about you know you can sort of
12947
09:25:01,500 --> 09:25:02,500
pick and choose there are best practices
12948
09:25:03,240 --> 09:25:04,240
but the computer is always going to be
12949
09:25:04,560 --> 09:25:05,560
able to figure it out okay
12950
09:25:06,360 --> 09:25:07,360
now the second rule is that successive
12951
09:25:10,220 --> 09:25:11,220
zeros or successive sets of zeros can be
12952
09:25:13,620 --> 09:25:14,620
removed but they can only be removed
12953
09:25:15,480 --> 09:25:16,480
once so any sets of successive zeros and
12954
09:25:18,720 --> 09:25:19,720
here we see
12955
09:25:19,916 --> 09:25:20,916
one set or two sets rather successive
12956
09:25:22,320 --> 09:25:23,320
zeros can be removed and replaced
12957
09:25:25,320 --> 09:25:26,320
with a double colon
12958
09:25:27,360 --> 09:25:28,360
now the reason we can only apply that
12959
09:25:30,060 --> 09:25:31,060
once is let's say these zeros
12960
09:25:34,040 --> 09:25:35,040
were we had another set of zeros over
12961
09:25:37,200 --> 09:25:38,200
here and we
12962
09:25:39,360 --> 09:25:40,360
um
12963
09:25:40,020 --> 09:25:41,020
truncated those
12964
09:25:42,120 --> 09:25:43,120
we can add up right we know there's one
12965
09:25:44,520 --> 09:25:45,520
two three four five six sets here so we
12966
09:25:49,436 --> 09:25:50,436
know that this represents two sets
12967
09:25:52,800 --> 09:25:53,800
of missing zeros but for instance if we
12968
09:25:56,340 --> 09:25:57,340
had you know two other sets
12969
09:25:58,500 --> 09:25:59,500
here and we remove those we might not
12970
09:26:01,436 --> 09:26:02,436
know
12971
09:26:02,460 --> 09:26:03,460
whether it's supposed to be one set and
12972
09:26:04,916 --> 09:26:05,916
three sets or two sets and two sets and
12973
09:26:07,020 --> 09:26:08,020
so on and so forth so we can only do
12974
09:26:09,060 --> 09:26:10,060
this once because when we add them back
12975
09:26:11,276 --> 09:26:12,276
there's no way to know
12976
09:26:13,620 --> 09:26:14,620
um
12977
09:26:14,460 --> 09:26:15,460
uh you know where that would sort of lie
12978
09:26:19,256 --> 09:26:20,256
now uh I'm just gonna erase this for a
12979
09:26:21,900 --> 09:26:22,900
second because we can even truncate this
12980
09:26:24,360 --> 09:26:25,360
more we've applied this rule
12981
09:26:27,120 --> 09:26:28,120
so this applies this rule this one is
12982
09:26:29,640 --> 09:26:30,640
applied this rule but we can apply both
12983
09:26:31,256 --> 09:26:32,256
rules right so we can remove these
12984
09:26:33,900 --> 09:26:34,900
leading zeros here and actually write
12985
09:26:36,000 --> 09:26:37,000
this out
12986
09:26:37,200 --> 09:26:38,200
as 2001
12987
09:26:40,680 --> 09:26:41,680
d8
12988
09:26:42,480 --> 09:26:43,480
eight eight a three double colon which
12989
09:26:46,380 --> 09:26:47,380
means that those are successive zeros
12990
09:26:49,256 --> 09:26:50,256
three e seven zero seven three three
12991
09:26:53,700 --> 09:26:54,700
four
12992
09:26:54,596 --> 09:26:55,596
now let's just I just want to uh sort of
12993
09:26:57,540 --> 09:26:58,540
follow up and explain write out what I
12994
09:27:00,060 --> 09:27:01,060
was just talking about with why we can't
12995
09:27:01,916 --> 09:27:02,916
have more than two sets of successive
12996
09:27:03,960 --> 09:27:04,960
zeros okay let's say that we have zeros
12997
09:27:08,756 --> 09:27:09,756
here as well
12998
09:27:10,500 --> 09:27:11,500
okay so I'm gonna rewrite this out we
12999
09:27:12,960 --> 09:27:13,960
have zero zero zero zero colon zero zero
13000
09:27:16,800 --> 09:27:17,800
zero zero colon zero eight
13001
09:27:21,020 --> 09:27:22,020
A3 colon zero zero zero zero zero zero
13002
09:27:26,640 --> 09:27:27,640
zero zero
13003
09:27:28,800 --> 09:27:29,800
eight c three e zero zero seven zero
13004
09:27:34,500 --> 09:27:35,500
seven three three four okay
13005
09:27:37,256 --> 09:27:38,256
let's first apply our first rule which
13006
09:27:39,180 --> 09:27:40,180
is that leading zeros can be removed so
13007
09:27:41,640 --> 09:27:42,640
we rewrite this and we're going to get
13008
09:27:42,960 --> 09:27:43,960
this
13009
09:27:58,140 --> 09:27:59,140
okay now we're allowed to remove one set
13010
09:28:02,096 --> 09:28:03,096
of leading of successive zeros only
13011
09:28:04,020 --> 09:28:05,020
which is the second rule okay but let's
13012
09:28:06,540 --> 09:28:07,540
do it twice and just see what happens so
13013
09:28:09,300 --> 09:28:10,300
let's say we have a double colon here
13014
09:28:12,680 --> 09:28:13,680
8a3 and then we have another double
13015
09:28:15,480 --> 09:28:16,480
colon
13016
09:28:17,040 --> 09:28:18,040
8c3e
13017
09:28:20,040 --> 09:28:21,040
seven zero
13018
09:28:21,960 --> 09:28:22,960
seven three three four now
13019
09:28:24,960 --> 09:28:25,960
let's say we want to expand this back
13020
09:28:27,000 --> 09:28:28,000
out to its full version
13021
09:28:29,160 --> 09:28:30,160
well if we have the successive zeros
13022
09:28:31,980 --> 09:28:32,980
here
13023
09:28:33,480 --> 09:28:34,480
we don't know if this would be written
13024
09:28:35,756 --> 09:28:36,756
out zero zero zero zero
13025
09:28:40,020 --> 09:28:41,020
dot 883
13026
09:28:46,800 --> 09:28:47,800
because from what we're seeing here
13027
09:28:51,120 --> 09:28:52,120
theoretically we could put three zeros
13028
09:28:54,120 --> 09:28:55,120
here and one zero here right or we could
13029
09:28:56,276 --> 09:28:57,276
do it the other way around so the reason
13030
09:28:57,480 --> 09:28:58,480
we can only do it once is because then
13031
09:28:59,160 --> 09:29:00,160
mathematically we know exactly
13032
09:29:02,700 --> 09:29:03,700
how many belong when we do that all
13033
09:29:05,400 --> 09:29:06,400
right so hopefully that helps clarify
13034
09:29:07,436 --> 09:29:08,436
the reason behind the success of zeros
13035
09:29:10,020 --> 09:29:11,020
being removed
13036
09:29:12,240 --> 09:29:13,240
all right now uh what this also means is
13037
09:29:15,416 --> 09:29:16,416
that if you remember a loopback address
13038
09:29:17,096 --> 09:29:18,096
an ipv4
13039
09:29:21,000 --> 09:29:22,000
the loopback was
13040
09:29:23,776 --> 09:29:24,776
127.0.0.1 while we also have a loop back
13041
09:29:26,400 --> 09:29:27,400
when it comes to IPv6
13042
09:29:28,680 --> 09:29:29,680
that's all these zeros to one but
13043
09:29:31,320 --> 09:29:32,320
because we can apply all of these rules
13044
09:29:34,140 --> 09:29:35,140
we can truncate this to Simply this
13045
09:29:38,096 --> 09:29:39,096
all right
13046
09:29:39,540 --> 09:29:40,540
so uh this is important to remember
13047
09:29:41,880 --> 09:29:42,880
these rules are important to remember
13048
09:29:43,436 --> 09:29:44,436
the other thing I want you to remember
13049
09:29:44,700 --> 09:29:45,700
is that hexadecimal
13050
09:29:47,936 --> 09:29:48,936
zero to nine a to f so they might show
13051
09:29:52,380 --> 09:29:53,380
you something and say which of these is
13052
09:29:53,756 --> 09:29:54,756
not a valid IP
13053
09:29:56,400 --> 09:29:57,400
if it has a letter say G or an H then
13054
09:29:59,700 --> 09:30:00,700
you know it's not going to be valid and
13055
09:30:01,916 --> 09:30:02,916
here we can check here's a d That's good
13056
09:30:04,620 --> 09:30:05,620
here's an a that's good C good
13057
09:30:08,096 --> 09:30:09,096
e good so this is good to go right if we
13058
09:30:11,936 --> 09:30:12,936
had an H or a g or an X for instance
13059
09:30:14,580 --> 09:30:15,580
then we would know that the um IPv6 was
13060
09:30:18,300 --> 09:30:19,300
incorrect because there's no hexadecimal
13061
09:30:20,520 --> 09:30:21,520
symbol X
13062
09:30:21,720 --> 09:30:22,720
so the ipv4 addressing method is is
13063
09:30:25,680 --> 09:30:26,680
really different from IPv6 addressing
13064
09:30:28,080 --> 09:30:29,080
and it's comparatively it's lacking in
13065
09:30:31,800 --> 09:30:32,800
many areas first as we've talked about
13066
09:30:33,900 --> 09:30:34,900
we're using a 32-bit binary address in
13067
09:30:37,020 --> 09:30:38,020
ipv4 versus a
13068
09:30:39,980 --> 09:30:40,980
128-bit binary address in IPv6 and of
13069
09:30:44,700 --> 09:30:45,700
course this greatly increases the number
13070
09:30:47,160 --> 09:30:48,160
of possible IP addresses I think around
13071
09:30:50,096 --> 09:30:51,096
February of 2011 all of these IP
13072
09:30:53,160 --> 09:30:54,160
addresses had been leased and uh so
13073
09:30:56,820 --> 09:30:57,820
there weren't any addresses left I think
13074
09:30:58,500 --> 09:30:59,500
we had something right like 4.8 0.7
13075
09:31:00,840 --> 09:31:01,840
billion right and all those were gone
13076
09:31:03,060 --> 09:31:04,060
and so we were depleted of all of our IP
13077
09:31:06,540 --> 09:31:07,540
addresses
13078
09:31:07,800 --> 09:31:08,800
so this is why we had to transition to
13079
09:31:09,776 --> 09:31:10,776
IPv6 because now we have that
13080
09:31:12,300 --> 09:31:13,300
undecillion uh address which again is if
13081
09:31:15,240 --> 09:31:16,240
every there were a trillion people they
13082
09:31:17,400 --> 09:31:18,400
could each have a trillion addresses now
13083
09:31:20,160 --> 09:31:21,160
another major difference between these
13084
09:31:22,916 --> 09:31:23,916
two is that uh ipv4
13085
09:31:25,820 --> 09:31:26,820
utilized the classless inter-domain
13086
09:31:29,300 --> 09:31:30,300
routing notation if you remember which
13087
09:31:31,436 --> 09:31:32,436
had that slash and then a number of bits
13088
09:31:33,596 --> 09:31:34,596
well
13089
09:31:35,580 --> 09:31:36,580
in IPv6 this isn't necessary and IPv6
13090
09:31:39,900 --> 09:31:40,900
actually has a subnet size of 2 to the
13091
09:31:42,360 --> 09:31:43,360
64 power now if you remember
13092
09:31:46,500 --> 09:31:47,500
that the total IPv6 is 2 to the 128 then
13093
09:31:50,936 --> 09:31:51,936
what you realize is that the first half
13094
09:31:53,160 --> 09:31:54,160
of the IPv6 address so if we were to
13095
09:31:56,700 --> 09:31:57,700
write one out again let's say 2 0 8 a
13096
09:32:03,256 --> 09:32:04,256
3 6 4.
13097
09:32:06,240 --> 09:32:07,240
uh nine two B
13098
09:32:11,756 --> 09:32:12,756
f
13099
09:32:14,360 --> 09:32:15,360
one zero zero zero right okay so then
13100
09:32:18,840 --> 09:32:19,840
we're gonna have four more on this side
13101
09:32:20,220 --> 09:32:21,220
the first four
13102
09:32:22,140 --> 09:32:23,140
which again is the first 64 bits that's
13103
09:32:24,720 --> 09:32:25,720
the subnet
13104
09:32:25,860 --> 09:32:26,860
so now we've integrated the subnet into
13105
09:32:28,140 --> 09:32:29,140
the IPv6 address which is the benefit
13106
09:32:30,720 --> 09:32:31,720
now we don't have to sort of have this
13107
09:32:33,120 --> 09:32:34,120
extra
13108
09:32:34,320 --> 09:32:35,320
uh uh written out cidr thing so it's
13109
09:32:37,800 --> 09:32:38,800
been standardized it's always 2 to the
13110
09:32:39,596 --> 09:32:40,596
64. we always know the subnet or the
13111
09:32:42,300 --> 09:32:43,300
network node is on the first
13112
09:32:46,140 --> 09:32:47,140
section and the node ID is on the
13113
09:32:48,840 --> 09:32:49,840
section the second section the other two
13114
09:32:51,000 --> 09:32:52,000
to the 64. so this really help helps us
13115
09:32:54,240 --> 09:32:55,240
simplify things to a great extent now
13116
09:32:56,580 --> 09:32:57,580
obviously one of the issues is we're
13117
09:32:58,020 --> 09:32:59,020
going to under use a lot of the
13118
09:33:00,540 --> 09:33:01,540
addresses we're going to under use many
13119
09:33:01,980 --> 09:33:02,980
of our addresses because we're never
13120
09:33:03,596 --> 09:33:04,596
going to have to really use this many
13121
09:33:04,860 --> 09:33:05,860
subnets or perhaps not even that many
13122
09:33:07,140 --> 09:33:08,140
networks right but um there are so many
13123
09:33:10,380 --> 09:33:11,380
other benefits that it has with routing
13124
09:33:12,360 --> 09:33:13,360
and efficiency and simplified management
13125
09:33:14,756 --> 09:33:15,756
that it it sort of
13126
09:33:17,340 --> 09:33:18,340
um makes up for it and so that's why
13127
09:33:19,916 --> 09:33:20,916
we're going to make that sacrifice now
13128
09:33:22,916 --> 09:33:23,916
in terms of domain name systems uh with
13129
09:33:25,980 --> 09:33:26,980
DNS when we talked about for instance a
13130
09:33:28,916 --> 09:33:29,916
google.com
13131
09:33:31,620 --> 09:33:32,620
going over to say you know whatever that
13132
09:33:35,580 --> 09:33:36,580
IP address is
13133
09:33:40,320 --> 09:33:41,320
I'm making this one up obviously it's
13134
09:33:42,300 --> 09:33:43,300
not a real one because we're in a
13135
09:33:43,680 --> 09:33:44,680
private IP
13136
09:33:45,180 --> 09:33:46,180
but this was called an a record right so
13137
09:33:48,060 --> 09:33:49,060
a server would have something or a DNS
13138
09:33:50,276 --> 09:33:51,276
server would have something called an a
13139
09:33:51,596 --> 09:33:52,596
record and that a record had this
13140
09:33:54,596 --> 09:33:55,596
information in it
13141
09:33:57,180 --> 09:33:58,180
all right now when we're dealing with
13142
09:33:59,240 --> 09:34:00,240
IPv6 we're utilizing
13143
09:34:02,040 --> 09:34:03,040
a quad a record for this mapping now we
13144
09:34:05,880 --> 09:34:06,880
can also use the same a record but this
13145
09:34:08,040 --> 09:34:09,040
quad a record can be used as well so if
13146
09:34:10,200 --> 09:34:11,200
you see Four A's what we call a 4A
13147
09:34:14,040 --> 09:34:15,040
record or a quad a record then you know
13148
09:34:16,500 --> 09:34:17,500
we're using IPv6 it's one of the
13149
09:34:18,360 --> 09:34:19,360
differences and again these are the
13150
09:34:20,400 --> 09:34:21,400
records that are used to map IP
13151
09:34:22,800 --> 09:34:23,800
addresses to what are called fully
13152
09:34:25,980 --> 09:34:26,980
qualified domain names
13153
09:34:28,740 --> 09:34:29,740
now while comparing these two schemes
13154
09:34:31,020 --> 09:34:32,020
also
13155
09:34:32,360 --> 09:34:33,360
ipsec which stands for IP
13156
09:34:35,220 --> 09:34:36,220
security is another aspect that we need
13157
09:34:37,680 --> 09:34:38,680
to consider in ipv4 ipsec is optional
13158
09:34:42,360 --> 09:34:43,360
it's widely used for secure traffic over
13159
09:34:46,256 --> 09:34:47,256
ipv4 Communications but when we dealt
13160
09:34:50,160 --> 09:34:51,160
with
13161
09:34:51,680 --> 09:34:52,680
IPv6 ipsec was designed for it and so uh
13162
09:34:56,520 --> 09:34:57,520
it's required from the original
13163
09:34:58,200 --> 09:34:59,200
specification and therefore all
13164
09:35:00,960 --> 09:35:01,960
Communications that are working over
13165
09:35:02,640 --> 09:35:03,640
IPv6 are automatically falling under
13166
09:35:04,936 --> 09:35:05,936
ipsec so it can be considered in some
13167
09:35:10,256 --> 09:35:11,256
ways optional I guess but it is required
13168
09:35:14,400 --> 09:35:15,400
use from the get-go because it was built
13169
09:35:18,120 --> 09:35:19,120
into IPv6 now the IPv6 scheme can also
13170
09:35:22,320 --> 09:35:23,320
handle a much larger packet size the
13171
09:35:25,500 --> 09:35:26,500
packet size for ipv4 is 65 535 octets
13172
09:35:29,936 --> 09:35:30,936
payload when we get to IPv6 we're
13173
09:35:32,820 --> 09:35:33,820
dealing with a
13174
09:35:34,040 --> 09:35:35,040
4.295 billion octets of payload so
13175
09:35:37,916 --> 09:35:38,916
obviously these are a lot bigger these
13176
09:35:39,480 --> 09:35:40,480
are what we call
13177
09:35:40,820 --> 09:35:41,820
jumbo grams
13178
09:35:43,436 --> 09:35:44,436
as a result you can imagine that if we
13179
09:35:45,960 --> 09:35:46,960
want to deal with ipv4 and we're on an
13180
09:35:48,360 --> 09:35:49,360
IPv6 Network we're going to have to make
13181
09:35:50,580 --> 09:35:51,580
up for this now if you recall we were
13182
09:35:52,860 --> 09:35:53,860
talking about ethernet we also were
13183
09:35:54,720 --> 09:35:55,720
talking about the header sizes and all
13184
09:35:56,220 --> 09:35:57,220
the information that was contained in
13185
09:35:57,540 --> 09:35:58,540
there well the header size for ipv4 and
13186
09:36:00,900 --> 09:36:01,900
IPv6 is also very different which
13187
09:36:03,660 --> 09:36:04,660
actually makes these two
13188
09:36:06,740 --> 09:36:07,740
protocols not compatible with each other
13189
09:36:09,416 --> 09:36:10,416
so IPv6 is not compatible with ipv4
13190
09:36:13,380 --> 09:36:14,380
and so the way we're going to
13191
09:36:15,416 --> 09:36:16,416
communicate with an IPv6
13192
09:36:19,980 --> 09:36:20,980
over an ipv4 network if we need to is by
13193
09:36:23,400 --> 09:36:24,400
tunneling
13194
09:36:25,320 --> 09:36:26,320
the packets in other words we take an
13195
09:36:27,720 --> 09:36:28,720
ipv4 packet I mean an IPv6 packet and we
13196
09:36:32,700 --> 09:36:33,700
literally wrap
13197
09:36:34,916 --> 09:36:35,916
it around
13198
09:36:37,080 --> 09:36:38,080
where we wrap around it in ipv4 packet
13199
09:36:39,840 --> 09:36:40,840
and so we tunnel the IPv6 packet inside
13200
09:36:43,140 --> 09:36:44,140
of the ipv4 now this allows it to
13201
09:36:45,960 --> 09:36:46,960
communicate but this is also what we
13202
09:36:47,756 --> 09:36:48,756
call a dual
13203
09:36:50,700 --> 09:36:51,700
foreign
13204
09:36:52,276 --> 09:36:53,276
in some cases we can have what's called
13205
09:36:54,300 --> 09:36:55,300
a dual stack where we have an ipv4 and
13206
09:36:57,840 --> 09:36:58,840
an IPv6 and so we can choose which one
13207
09:37:00,120 --> 09:37:01,120
to go over and then this tunneling is
13208
09:37:01,980 --> 09:37:02,980
not going to be necessary now
13209
09:37:04,916 --> 09:37:05,916
we don't really want a tunnel because
13210
09:37:06,596 --> 09:37:07,596
obviously the payloads are so much
13211
09:37:08,276 --> 09:37:09,276
different in size that it's going to
13212
09:37:09,540 --> 09:37:10,540
cause all sorts of trouble so what we'll
13213
09:37:11,700 --> 09:37:12,700
try to do is create this dual stack in
13214
09:37:13,740 --> 09:37:14,740
which we have one network and the other
13215
09:37:16,500 --> 09:37:17,500
and they're both operating sort of side
13216
09:37:18,360 --> 09:37:19,360
by side if we can't do that then we have
13217
09:37:20,756 --> 09:37:21,756
to use tunneling in order to move the
13218
09:37:23,460 --> 09:37:24,460
IPv6 data over an ipv4 Network which
13219
09:37:27,000 --> 09:37:28,000
might be necessary even if the IPv6 data
13220
09:37:30,540 --> 09:37:31,540
is traveling through an ipv4 Network
13221
09:37:33,060 --> 09:37:34,060
all right so we've compared these let's
13222
09:37:34,680 --> 09:37:35,680
talk about some of the improvements that
13223
09:37:36,660 --> 09:37:37,660
ipv4 did not have that IPv6 does uh
13224
09:37:40,980 --> 09:37:41,980
starting with some security and privacy
13225
09:37:43,800 --> 09:37:44,800
measures if privacy extensions are
13226
09:37:47,756 --> 09:37:48,756
enabled with IPv6 then we have something
13227
09:37:51,840 --> 09:37:52,840
called an ephemeral address which is
13228
09:37:54,120 --> 09:37:55,120
created
13229
09:37:55,380 --> 09:37:56,380
and this is used as a temporary and
13230
09:37:58,080 --> 09:37:59,080
random address that's used to
13231
09:37:59,700 --> 09:38:00,700
communicate with external devices but
13232
09:38:02,340 --> 09:38:03,340
the external device doesn't know the
13233
09:38:04,200 --> 09:38:05,200
true address of the internal device and
13234
09:38:05,936 --> 09:38:06,936
so this improves the the privacy and
13235
09:38:09,240 --> 09:38:10,240
security for the user and this is what
13236
09:38:11,580 --> 09:38:12,580
we call a privacy extension and it does
13237
09:38:13,620 --> 09:38:14,620
have to be enabled
13238
09:38:16,320 --> 09:38:17,320
some sort of a router point of view now
13239
09:38:19,020 --> 09:38:20,020
another Improvement is a better
13240
09:38:20,936 --> 09:38:21,936
composition of what we call the unicast
13241
09:38:22,916 --> 09:38:23,916
address what this means is that IPv6
13242
09:38:25,560 --> 09:38:26,560
uses a unicast addressing structure to
13243
09:38:29,580 --> 09:38:30,580
replace the classful addresses of ipv4
13244
09:38:33,200 --> 09:38:34,200
this offers a lot more flexibility and
13245
09:38:36,240 --> 09:38:37,240
efficiency with addressing and depending
13246
09:38:38,820 --> 09:38:39,820
on the category of the unicast address
13247
09:38:40,620 --> 09:38:41,620
used there are different functions for
13248
09:38:42,776 --> 09:38:43,776
each meaning that there are different
13249
09:38:45,596 --> 09:38:46,596
types of addresses that are used and
13250
09:38:47,820 --> 09:38:48,820
that way the computer automatically
13251
09:38:49,620 --> 09:38:50,620
knows what the function is the first is
13252
09:38:52,020 --> 09:38:53,020
called a global address which is sort of
13253
09:38:54,960 --> 09:38:55,960
like the public or routable addresses uh
13254
09:38:58,436 --> 09:38:59,436
in ipv4 if you recall most addresses
13255
09:39:01,320 --> 09:39:02,320
could be routed those are what we call
13256
09:39:03,360 --> 09:39:04,360
Global addresses
13257
09:39:05,160 --> 09:39:06,160
we also have site local addresses which
13258
09:39:08,160 --> 09:39:09,160
are essentially like the private
13259
09:39:09,720 --> 09:39:10,720
addresses or non-routable addresses that
13260
09:39:12,060 --> 09:39:13,060
are not routable to external networks if
13261
09:39:14,040 --> 09:39:15,040
you recall
13262
09:39:15,300 --> 09:39:16,300
these were for instance the
13263
09:39:19,220 --> 09:39:20,220
10.0.0.0 through
13264
09:39:22,880 --> 09:39:23,880
10.255.255 at 255 and then the
13265
09:39:27,200 --> 09:39:28,200
172.16-32 and then the 192.168 those are
13266
09:39:31,256 --> 09:39:32,256
the private addresses well in IPv6 we
13267
09:39:34,200 --> 09:39:35,200
call them site local addresses we also
13268
09:39:36,900 --> 09:39:37,900
have something called link local
13269
09:39:38,220 --> 09:39:39,220
addresses which are basically comparable
13270
09:39:40,200 --> 09:39:41,200
to a pipa addresses in ipv4 and we're
13271
09:39:43,980 --> 09:39:44,980
going to talk more about what those mean
13272
09:39:45,360 --> 09:39:46,360
in just a little bit later but just to
13273
09:39:48,360 --> 09:39:49,360
give you a little heads up and we have
13274
09:39:50,220 --> 09:39:51,220
talked about it with uh uh a plus if you
13275
09:39:53,700 --> 09:39:54,700
around for that this is automatic
13276
09:39:56,700 --> 09:39:57,700
private
13277
09:39:58,860 --> 09:39:59,860
IP addressing and we need because every
13278
09:40:03,000 --> 09:40:04,000
device needs an automatic IP address if
13279
09:40:05,276 --> 09:40:06,276
it's not given one by a server then it's
13280
09:40:07,436 --> 09:40:08,436
going to give itself one what we call an
13281
09:40:08,936 --> 09:40:09,936
apipa address and so in IPv6 these are
13282
09:40:12,060 --> 09:40:13,060
called link local addresses
13283
09:40:15,060 --> 09:40:16,060
finally there are IPv6 transitional
13284
09:40:17,756 --> 09:40:18,756
addresses which are basically going to
13285
09:40:19,680 --> 09:40:20,680
be used in the time being until we phase
13286
09:40:22,020 --> 09:40:23,020
out of ipv4 these are used to Route IPv6
13287
09:40:27,000 --> 09:40:28,000
traffic across ipv4 networks through
13288
09:40:30,240 --> 09:40:31,240
tunneling much like I've just described
13289
09:40:31,980 --> 09:40:32,980
in the previous section
13290
09:40:36,416 --> 09:40:37,416
now a mechanism uh built into IPv6
13291
09:40:40,320 --> 09:40:41,320
addresses is a field located in the IP
13292
09:40:43,860 --> 09:40:44,860
header
13293
09:40:47,160 --> 09:40:48,160
that's designed to guarantee network
13294
09:40:49,560 --> 09:40:50,560
resources be allowed allocated to
13295
09:40:52,140 --> 09:40:53,140
services that need time sensitive data
13296
09:40:54,300 --> 09:40:55,300
such as voice over IP right we need that
13297
09:40:57,540 --> 09:40:58,540
that is time sensitive because I'm
13298
09:40:58,980 --> 09:40:59,980
talking and I want the person to hear
13299
09:41:00,180 --> 09:41:01,180
almost as soon as I talk and so this
13300
09:41:02,276 --> 09:41:03,276
time sensitive stuff is built into IPv6
13301
09:41:05,400 --> 09:41:06,400
one of the reasons that we use it now
13302
09:41:07,436 --> 09:41:08,436
another improvement with this scheme
13303
09:41:09,360 --> 09:41:10,360
IPv6 is called hierarchical addressing
13304
09:41:12,240 --> 09:41:13,240
this eliminates the random allocation of
13305
09:41:14,820 --> 09:41:15,820
addresses so connectivity devices such
13306
09:41:18,120 --> 09:41:19,120
as top level routers are assigned a top
13307
09:41:21,480 --> 09:41:22,480
level block of ivv6 addresses and then
13308
09:41:25,500 --> 09:41:26,500
segments are added to those with blocks
13309
09:41:27,840 --> 09:41:28,840
of addresses that are assigned at that
13310
09:41:29,340 --> 09:41:30,340
level so basically it looks like a
13311
09:41:31,620 --> 09:41:32,620
hierarchy
13312
09:41:32,820 --> 09:41:33,820
from an IPv6 standpoint
13313
09:41:36,776 --> 09:41:37,776
you remember we looked at an uh this
13314
09:41:39,240 --> 09:41:40,240
sort of topology earlier
13315
09:41:41,820 --> 09:41:42,820
now ibv6 scheme also has a much
13316
09:41:44,340 --> 09:41:45,340
simplified header and it's going to make
13317
09:41:46,620 --> 09:41:47,620
addressing a lot easier to read
13318
09:41:48,960 --> 09:41:49,960
this improves the speed packet routing
13319
09:41:51,540 --> 09:41:52,540
on an individual packet basis so
13320
09:41:54,416 --> 09:41:55,416
obviously if we can
13321
09:41:56,220 --> 09:41:57,220
simplify how information can get read
13322
09:41:58,860 --> 09:41:59,860
it's going to simplify how routing can
13323
09:42:01,020 --> 09:42:02,020
occur
13324
09:42:02,096 --> 09:42:03,096
now data in transit is susceptible to a
13325
09:42:06,720 --> 09:42:07,720
variety of things that could cause it to
13326
09:42:08,220 --> 09:42:09,220
be delayed lost or damaged and these
13327
09:42:11,756 --> 09:42:12,756
things can occur on the transmit side
13328
09:42:13,740 --> 09:42:14,740
and quite commonly on the receiving side
13329
09:42:16,200 --> 09:42:17,200
as well so the method the data is
13330
09:42:18,720 --> 09:42:19,720
delivered makes a huge difference in
13331
09:42:20,520 --> 09:42:21,520
whether the data is going to arrive at
13332
09:42:22,256 --> 09:42:23,256
the destination correctively
13333
09:42:24,320 --> 09:42:25,320
and efficiently
13334
09:42:26,400 --> 09:42:27,400
so depending on the method of delivery
13335
09:42:28,380 --> 09:42:29,380
there can be error detection which would
13336
09:42:30,000 --> 09:42:31,000
mean we detect that there are errors and
13337
09:42:32,096 --> 09:42:33,096
error correction which means we not only
13338
09:42:34,020 --> 09:42:35,020
detect but we fix the errors when these
13339
09:42:36,000 --> 09:42:37,000
recovery mechanisms are used now an
13340
09:42:38,276 --> 09:42:39,276
important aspect of the data delivery
13341
09:42:40,320 --> 09:42:41,320
begins with the actual connection itself
13342
09:42:43,200 --> 09:42:44,200
so depending on the type of connection
13343
09:42:44,756 --> 09:42:45,756
service used is going to give us an idea
13344
09:42:47,820 --> 09:42:48,820
of what sort of delivery options are
13345
09:42:50,096 --> 09:42:51,096
available
13346
09:42:51,960 --> 09:42:52,960
so a connection in terms of networks is
13347
09:42:56,276 --> 09:42:57,276
The Logical joining of two network
13348
09:42:58,200 --> 09:42:59,200
devices through a specified medium that
13349
09:43:01,560 --> 09:43:02,560
is established and maintained for a
13350
09:43:03,596 --> 09:43:04,596
period of time during which the session
13351
09:43:05,700 --> 09:43:06,700
exists in other words the connection is
13352
09:43:09,120 --> 09:43:10,120
what allows data to be transferred
13353
09:43:10,916 --> 09:43:11,916
between say my computer and a server
13354
09:43:13,256 --> 09:43:14,256
computer
13355
09:43:14,160 --> 09:43:15,160
now in networking and specifically in IP
13356
09:43:17,340 --> 09:43:18,340
networks there will be connection
13357
09:43:19,080 --> 09:43:20,080
services that attempt to provide data
13358
09:43:23,096 --> 09:43:24,096
integrity and reliability now there are
13359
09:43:25,916 --> 09:43:26,916
generally three types of connection
13360
09:43:27,416 --> 09:43:28,416
services that we see when we discuss
13361
09:43:30,840 --> 09:43:31,840
certain protocols and we've talked about
13362
09:43:32,756 --> 09:43:33,756
these in some way shape or form but it
13363
09:43:35,520 --> 09:43:36,520
doesn't hurt to sort of go over them in
13364
09:43:37,256 --> 09:43:38,256
a little more specific detail
13365
09:43:39,120 --> 09:43:40,120
first is an acknowledged connectionless
13366
09:43:41,880 --> 09:43:42,880
service in these the connection isn't
13367
09:43:46,020 --> 09:43:47,020
created
13368
09:43:47,276 --> 09:43:48,276
however when data is received by the
13369
09:43:51,480 --> 09:43:52,480
destination there is a acknowledgment of
13370
09:43:54,720 --> 09:43:55,720
a receipt so website Communications use
13371
09:43:58,560 --> 09:43:59,560
this type of service a great metaphor to
13372
09:44:01,200 --> 09:44:02,200
think about this would be for instance a
13373
09:44:03,840 --> 09:44:04,840
delivery receipt
13374
09:44:06,120 --> 09:44:07,120
with regular mail
13375
09:44:10,200 --> 09:44:11,200
so it's not certified we're not going to
13376
09:44:12,416 --> 09:44:13,416
get a signature but what we do is we get
13377
09:44:14,520 --> 09:44:15,520
a receipt that it has been delivered now
13378
09:44:17,276 --> 09:44:18,276
with unacknowledged connectionless
13379
09:44:19,256 --> 09:44:20,256
Services there's no acknowledgment sent
13380
09:44:21,540 --> 09:44:22,540
unless the application itself does this
13381
09:44:24,240 --> 09:44:25,240
this could also be considered Simplex
13382
09:44:26,936 --> 09:44:27,936
Communications which we'll talk about in
13383
09:44:28,800 --> 09:44:29,800
just a second so this is just like
13384
09:44:31,140 --> 09:44:32,140
regular
13385
09:44:33,360 --> 09:44:34,360
mail
13386
09:44:34,620 --> 09:44:35,620
we send it we drop in the mail there is
13387
09:44:36,960 --> 09:44:37,960
no acknowledgment okay acknowledged at
13388
09:44:40,020 --> 09:44:41,020
least has
13389
09:44:41,096 --> 09:44:42,096
uh and acknowledge that data has been
13390
09:44:43,140 --> 09:44:44,140
sent but there is no connection made
13391
09:44:45,720 --> 09:44:46,720
right there is no established session
13392
09:44:48,300 --> 09:44:49,300
made between the receiver and the sender
13393
09:44:51,300 --> 09:44:52,300
finally we have connection oriented
13394
09:44:53,640 --> 09:44:54,640
services and by the way when we talked
13395
09:44:55,500 --> 09:44:56,500
about these connection lesses we recall
13396
09:44:59,220 --> 09:45:00,220
this is like UDP which is connectionless
13397
09:45:02,416 --> 09:45:03,416
and IP
13398
09:45:04,620 --> 09:45:05,620
here connection oriented we're looking
13399
09:45:06,540 --> 09:45:07,540
at TCP
13400
09:45:09,660 --> 09:45:10,660
now these are where error detection and
13401
09:45:12,416 --> 09:45:13,416
correction are available as well as some
13402
09:45:15,180 --> 09:45:16,180
flow controller packet sequencing in
13403
09:45:17,340 --> 09:45:18,340
other words this would be like certified
13404
09:45:19,256 --> 09:45:20,256
mail
13405
09:45:23,096 --> 09:45:24,096
now there are also three types of
13406
09:45:24,540 --> 09:45:25,540
connection modes that we're typically
13407
09:45:25,980 --> 09:45:26,980
going to use they're Simplex half duplex
13408
09:45:29,160 --> 09:45:30,160
and full duplex
13409
09:45:30,660 --> 09:45:31,660
with Simplex this is one way
13410
09:45:32,640 --> 09:45:33,640
communication only this is sort of
13411
09:45:34,980 --> 09:45:35,980
similar to FM radio broadcast
13412
09:45:38,520 --> 09:45:39,520
right you turn on your radio you tune in
13413
09:45:41,040 --> 09:45:42,040
and you can receive but you cannot send
13414
09:45:44,160 --> 09:45:45,160
data
13415
09:45:46,800 --> 09:45:47,800
now we also have half duplex this is
13416
09:45:49,500 --> 09:45:50,500
two-way communication but only one at a
13417
09:45:52,320 --> 09:45:53,320
time this is like a pair of regular
13418
09:45:54,360 --> 09:45:55,360
walkie-talkies only one device can
13419
09:45:57,180 --> 09:45:58,180
transmit at any one time which is why we
13420
09:46:00,776 --> 09:46:01,776
have to use those code words right over
13421
09:46:03,120 --> 09:46:04,120
over over and out so this is like a
13422
09:46:05,520 --> 09:46:06,520
walkie-talkie finally we have full
13423
09:46:07,436 --> 09:46:08,436
duplex which is two-way and both ways
13424
09:46:10,140 --> 09:46:11,140
simultaneously this is similar to the
13425
09:46:13,560 --> 09:46:14,560
telephone in which we can talk and
13426
09:46:16,256 --> 09:46:17,256
listen at the same time in some ways we
13427
09:46:19,140 --> 09:46:20,140
have trouble understanding each other as
13428
09:46:20,820 --> 09:46:21,820
a result of it now in networking devices
13429
09:46:23,276 --> 09:46:24,276
are designed to receive and transmit
13430
09:46:26,400 --> 09:46:27,400
data at different speeds and with
13431
09:46:28,916 --> 09:46:29,916
different sizes of packets as well so
13432
09:46:31,500 --> 09:46:32,500
certain devices are not going to be able
13433
09:46:33,180 --> 09:46:34,180
to handle as much data as others at one
13434
09:46:35,756 --> 09:46:36,756
point or another we talked about this
13435
09:46:37,200 --> 09:46:38,200
briefly with mtus and MTU black holes so
13436
09:46:40,436 --> 09:46:41,436
flow control is the managing of amounts
13437
09:46:43,916 --> 09:46:44,916
of data and the rate at which the data
13438
09:46:46,080 --> 09:46:47,080
is being transmitted emitted over a
13439
09:46:47,880 --> 09:46:48,880
network connection
13440
09:46:49,080 --> 09:46:50,080
flow control is necessary to help
13441
09:46:51,840 --> 09:46:52,840
prevent devices from being overflowed
13442
09:46:54,960 --> 09:46:55,960
with data some devices when there's too
13443
09:46:57,596 --> 09:46:58,596
much data is received are going to
13444
09:46:59,096 --> 09:47:00,096
potentially shut down to prevent certain
13445
09:47:01,500 --> 09:47:02,500
attacks or simply are going to drop
13446
09:47:03,596 --> 09:47:04,596
packets that are too large because
13447
09:47:05,520 --> 09:47:06,520
they're going to cause delays on the
13448
09:47:07,740 --> 09:47:08,740
other side of the scale if too little
13449
09:47:09,360 --> 09:47:10,360
data is being received by the device it
13450
09:47:11,700 --> 09:47:12,700
may just be sitting idly by waiting for
13451
09:47:13,916 --> 09:47:14,916
the remaining packets in this case it's
13452
09:47:16,620 --> 09:47:17,620
simply a matter of efficiency so there
13453
09:47:19,080 --> 09:47:20,080
are two main types of flow control that
13454
09:47:20,700 --> 09:47:21,700
are covered on the exam buffering and
13455
09:47:23,276 --> 09:47:24,276
data windows
13456
09:47:24,660 --> 09:47:25,660
buffering is a flow control technique
13457
09:47:27,596 --> 09:47:28,596
where a portion of the memory either
13458
09:47:29,820 --> 09:47:30,820
physical or logical via software is used
13459
09:47:33,060 --> 09:47:34,060
to temporarily store data as it's being
13460
09:47:35,580 --> 09:47:36,580
received in order to regulate the amount
13461
09:47:39,300 --> 09:47:40,300
of data that's being processed buffering
13462
09:47:41,880 --> 09:47:42,880
may be used to maintain data consistency
13463
09:47:44,040 --> 09:47:45,040
as well as minimize overloading now Ram
13464
09:47:47,640 --> 09:47:48,640
uses a type of buffer when data is being
13465
09:47:50,400 --> 09:47:51,400
read from its cache right so remember we
13466
09:47:53,160 --> 09:47:54,160
talked about RAM and that was what we
13467
09:47:55,436 --> 09:47:56,436
called Cash
13468
09:47:56,880 --> 09:47:57,880
now with buff bring there is a potential
13469
09:47:59,340 --> 09:48:00,340
concern because what if the buffer
13470
09:48:01,080 --> 09:48:02,080
becomes full well when receiving nodes
13471
09:48:03,300 --> 09:48:04,300
buffer reaches a certain capacity it
13472
09:48:05,820 --> 09:48:06,820
actually transmits a squelch signal I'm
13473
09:48:09,540 --> 09:48:10,540
going to write that out just not only
13474
09:48:10,680 --> 09:48:11,680
because it's a great word
13475
09:48:13,320 --> 09:48:14,320
that says stops transmission or slow
13476
09:48:16,800 --> 09:48:17,800
down your transmission so I can catch up
13477
09:48:20,040 --> 09:48:21,040
now a commonplace we're going to see
13478
09:48:21,416 --> 09:48:22,416
this type of flow controls when we're
13479
09:48:23,400 --> 09:48:24,400
streaming movies you might have seen
13480
09:48:25,380 --> 09:48:26,380
buffering when you're using movies for
13481
09:48:27,960 --> 09:48:28,960
instance on YouTube
13482
09:48:30,000 --> 09:48:31,000
or on Netflix or any of these sites the
13483
09:48:33,776 --> 09:48:34,776
idea is if there's a problem with our
13484
09:48:35,820 --> 09:48:36,820
communication
13485
09:48:37,080 --> 09:48:38,080
we have a little buffer of data so that
13486
09:48:39,480 --> 09:48:40,480
way we're not going to see a dip in
13487
09:48:41,880 --> 09:48:42,880
quality of the film
13488
09:48:43,436 --> 09:48:44,436
now another type of flow control is
13489
09:48:45,360 --> 09:48:46,360
called Data windows the data window
13490
09:48:48,240 --> 09:48:49,240
refers to the amount of data being sent
13491
09:48:50,460 --> 09:48:51,460
and it can either be a fixed amount or
13492
09:48:53,580 --> 09:48:54,580
it can vary and these are fixed length
13493
09:48:56,160 --> 09:48:57,160
windows or sliding very sliding Windows
13494
09:48:58,380 --> 09:48:59,380
rather if you think about the window
13495
09:49:02,160 --> 09:49:03,160
and I put the data inside of it
13496
09:49:04,620 --> 09:49:05,620
we can either have a window that is a
13497
09:49:06,540 --> 09:49:07,540
specific length like this
13498
09:49:08,580 --> 09:49:09,580
or
13499
09:49:10,860 --> 09:49:11,860
a window that can't possibly
13500
09:49:14,340 --> 09:49:15,340
get smaller based on the data
13501
09:49:18,240 --> 09:49:19,240
and that's what fixed length and sliding
13502
09:49:19,980 --> 09:49:20,980
windows are so to go a little more in
13503
09:49:21,900 --> 09:49:22,900
depth into these with fixed length
13504
09:49:24,596 --> 09:49:25,596
Windows the size of the packet of the
13505
09:49:26,700 --> 09:49:27,700
data being sent is determined by
13506
09:49:30,360 --> 09:49:31,360
the sender and the rate of transmission
13507
09:49:33,436 --> 09:49:34,436
is determined by the receiver so the
13508
09:49:36,480 --> 09:49:37,480
size is typically going to be pretty
13509
09:49:38,096 --> 09:49:39,096
small and overall this is going to be
13510
09:49:40,200 --> 09:49:41,200
fairly efficient the other thing to
13511
09:49:42,900 --> 09:49:43,900
remember is that the packet size is
13512
09:49:44,276 --> 09:49:45,276
always going to remain the same it's
13513
09:49:46,200 --> 09:49:47,200
never going to change so if I need to
13514
09:49:48,660 --> 09:49:49,660
send
13515
09:49:49,680 --> 09:49:50,680
10 packets they're all going to be
13516
09:49:51,660 --> 09:49:52,660
exactly the same size or as much as I
13517
09:49:55,140 --> 09:49:56,140
can draw them as such
13518
09:49:57,540 --> 09:49:58,540
and so on and so forth now with a
13519
09:50:00,120 --> 09:50:01,120
sliding window method it's a bit
13520
09:50:02,276 --> 09:50:03,276
different the sender begins to transmit
13521
09:50:04,436 --> 09:50:05,436
data typically with a small number of
13522
09:50:06,240 --> 09:50:07,240
packets and with each transmission
13523
09:50:09,540 --> 09:50:10,540
it uh waits for an acknowledgment or act
13524
09:50:14,040 --> 09:50:15,040
packet receipt now with each receipt
13525
09:50:17,220 --> 09:50:18,220
this contains the current maximum
13526
09:50:19,560 --> 09:50:20,560
threshold that can be reached and then
13527
09:50:21,660 --> 09:50:22,660
the transmitter is going to begin
13528
09:50:24,436 --> 09:50:25,436
increasing the number of packets by a
13529
09:50:27,000 --> 09:50:28,000
specified amount in other words it's
13530
09:50:29,700 --> 09:50:30,700
going to start sliding that window from
13531
09:50:32,276 --> 09:50:33,276
here
13532
09:50:33,120 --> 09:50:34,120
over
13533
09:50:34,740 --> 09:50:35,740
now it's going to continue to increase
13534
09:50:36,360 --> 09:50:37,360
this over and over and over
13535
09:50:39,480 --> 09:50:40,480
until we reach a maximum potential
13536
09:50:42,776 --> 09:50:43,776
at this point we're going to start
13537
09:50:44,276 --> 09:50:45,276
getting some congestion and so the
13538
09:50:47,520 --> 09:50:48,520
receiver is going to send another act
13539
09:50:49,200 --> 09:50:50,200
saying listen you need to slow down now
13540
09:50:50,880 --> 09:50:51,880
and and this is a good rate
13541
09:50:54,000 --> 09:50:55,000
this method is really going to allow for
13542
09:50:55,800 --> 09:50:56,800
minimal data traffic congestion and a
13543
09:50:58,740 --> 09:50:59,740
lot of throughput
13544
09:51:00,000 --> 09:51:01,000
depending on the amount of traffic the
13545
09:51:01,800 --> 09:51:02,800
size of the window can really vary
13546
09:51:03,540 --> 09:51:04,540
dramatically and so this really gives us
13547
09:51:05,520 --> 09:51:06,520
a lot more flexibility if you imagine if
13548
09:51:08,160 --> 09:51:09,160
I have a home that has a whole bunch of
13549
09:51:10,020 --> 09:51:11,020
irregular Windows I'm going to want
13550
09:51:11,936 --> 09:51:12,936
sliding Windows now if I have a home
13551
09:51:13,916 --> 09:51:14,916
with all these similar Windows
13552
09:51:15,540 --> 09:51:16,540
everything built the same then I can use
13553
09:51:17,096 --> 09:51:18,096
a fixed link window but this one's going
13554
09:51:18,900 --> 09:51:19,900
to give me a lot more flexibility
13555
09:51:21,596 --> 09:51:22,596
now error detection and correction is an
13556
09:51:24,660 --> 09:51:25,660
important aspect of how we know our
13557
09:51:26,520 --> 09:51:27,520
information arrives at the destination
13558
09:51:28,700 --> 09:51:29,700
unhindered and unaltered one method
13559
09:51:32,040 --> 09:51:33,040
achieves this by attaching supplemental
13560
09:51:34,800 --> 09:51:35,800
information at the end of the footer
13561
09:51:36,300 --> 09:51:37,300
that pertains to its contents and the
13562
09:51:38,880 --> 09:51:39,880
receiving station is going to look at
13563
09:51:40,140 --> 09:51:41,140
that data and compare it to the data it
13564
09:51:41,880 --> 09:51:42,880
received
13565
09:51:42,960 --> 09:51:43,960
the data matches it's going to consider
13566
09:51:44,580 --> 09:51:45,580
it error free if not the data is going
13567
09:51:46,916 --> 09:51:47,916
to be requested to be re-transmitted now
13568
09:51:49,436 --> 09:51:50,436
when an additional Correctional
13569
09:51:51,000 --> 09:51:52,000
component is added that allows the data
13570
09:51:53,220 --> 09:51:54,220
to be rebuilt in the error in the event
13571
09:51:55,380 --> 09:51:56,380
of an error this is going to become an
13572
09:51:57,120 --> 09:51:58,120
edac or error detection and correction
13573
09:52:01,020 --> 09:52:02,020
now parity check is a process where an
13574
09:52:04,020 --> 09:52:05,020
extra bit is added to every word of data
13575
09:52:06,960 --> 09:52:07,960
the receiving station can look for the
13576
09:52:09,120 --> 09:52:10,120
bit on this word by word basis remember
13577
09:52:11,936 --> 09:52:12,936
we're talking about words we're not
13578
09:52:13,500 --> 09:52:14,500
talking about uh language we're talking
13579
09:52:16,080 --> 09:52:17,080
about words as far as data goes and so
13580
09:52:18,776 --> 09:52:19,776
it can look at these and therefore it
13581
09:52:20,756 --> 09:52:21,756
can determine any errors that are built
13582
09:52:23,460 --> 09:52:24,460
in because parity adds this extra bit to
13583
09:52:27,660 --> 09:52:28,660
every word this method takes a little
13584
09:52:29,640 --> 09:52:30,640
bit of overhead so it does ADD
13585
09:52:34,740 --> 09:52:35,740
not only extra resources but some more
13586
09:52:37,020 --> 09:52:38,020
data in there now with something called
13587
09:52:38,756 --> 09:52:39,756
CRC or cyclic redundancy check a code is
13588
09:52:42,540 --> 09:52:43,540
added to every block of data through a
13589
09:52:45,300 --> 09:52:46,300
mathematical operation
13590
09:52:47,520 --> 09:52:48,520
which is also referred to as hashing
13591
09:52:50,756 --> 09:52:51,756
now this code is added to the end of the
13592
09:52:53,160 --> 09:52:54,160
block and then it's transmitted
13593
09:52:55,980 --> 09:52:56,980
when the receiving station applies this
13594
09:52:59,276 --> 09:53:00,276
hashing method this mathematical
13595
09:53:00,660 --> 09:53:01,660
operation to the code
13596
09:53:02,580 --> 09:53:03,580
then it can should get the same data and
13597
09:53:05,936 --> 09:53:06,936
if it doesn't then it knows there's a
13598
09:53:07,500 --> 09:53:08,500
problem and it can request it to be
13599
09:53:09,416 --> 09:53:10,416
resent like parity CRC is also going to
13600
09:53:12,596 --> 09:53:13,596
add a certain amount of overhead because
13601
09:53:14,640 --> 09:53:15,640
it takes data and calculation time all
13602
09:53:17,040 --> 09:53:18,040
right so now just to review some of the
13603
09:53:19,560 --> 09:53:20,560
topics we talked about we talked about
13604
09:53:21,480 --> 09:53:22,480
the IPv6 addressing scheme specifically
13605
09:53:25,320 --> 09:53:26,320
we talked to that it's a hexadecimal
13606
09:53:28,340 --> 09:53:29,340
128 bits
13607
09:53:31,140 --> 09:53:32,140
divided into
13608
09:53:32,936 --> 09:53:33,936
eight sections
13609
09:53:35,460 --> 09:53:36,460
we also compared and contrasted IPv6
13610
09:53:38,640 --> 09:53:39,640
with ipv4 we saw that IPv6 for instance
13611
09:53:42,000 --> 09:53:43,000
has ipsec built in
13612
09:53:44,160 --> 09:53:45,160
and has a whole bunch of other
13613
09:53:46,160 --> 09:53:47,160
improvements and mechanisms such as data
13614
09:53:50,040 --> 09:53:51,040
delivery time sensitive and so on and so
13615
09:53:53,460 --> 09:53:54,460
forth the important thing I really want
13616
09:53:55,320 --> 09:53:56,320
you to know about IPv6
13617
09:53:57,540 --> 09:53:58,540
is that it does not require
13618
09:54:00,416 --> 09:54:01,416
a subnet
13619
09:54:02,276 --> 09:54:03,276
and we need to recall all of the
13620
09:54:05,340 --> 09:54:06,340
truncation or readability rules
13621
09:54:08,700 --> 09:54:09,700
which include removing leading zeros
13622
09:54:14,400 --> 09:54:15,400
and
13623
09:54:17,416 --> 09:54:18,416
combining successive
13624
09:54:21,120 --> 09:54:22,120
sets of zeros
13625
09:54:22,980 --> 09:54:23,980
but only once
13626
09:54:26,640 --> 09:54:27,640
we also explained the different data
13627
09:54:28,620 --> 09:54:29,620
delivery techniques and we defined a
13628
09:54:31,560 --> 09:54:32,560
connection the different connection
13629
09:54:33,060 --> 09:54:34,060
modes whether they're acknowledged
13630
09:54:34,860 --> 09:54:35,860
connectionless
13631
09:54:39,416 --> 09:54:40,416
simply unacknowledged connectionless
13632
09:54:42,720 --> 09:54:43,720
or connection oriented
13633
09:54:45,660 --> 09:54:46,660
we also looked at the different transmit
13634
09:54:47,640 --> 09:54:48,640
types including Simplex which is one way
13635
09:54:51,540 --> 09:54:52,540
half duplex which is like our
13636
09:54:53,220 --> 09:54:54,220
walkie-talkie
13637
09:54:55,620 --> 09:54:56,620
and full duplex
13638
09:54:57,840 --> 09:54:58,840
which in effect doubles our bandwidth
13639
09:55:01,140 --> 09:55:02,140
we also explained flow control buffering
13640
09:55:03,840 --> 09:55:04,840
and data windows we use buffering a lot
13641
09:55:06,300 --> 09:55:07,300
when we're talking about videos in data
13642
09:55:08,520 --> 09:55:09,520
Windows remember we talked about the
13643
09:55:10,020 --> 09:55:11,020
fixed
13644
09:55:13,200 --> 09:55:14,200
and sliding windows
13645
09:55:16,200 --> 09:55:17,200
finally we outlined error detection
13646
09:55:18,660 --> 09:55:19,660
methods including parity which adds an
13647
09:55:22,140 --> 09:55:23,140
extra bit to every word
13648
09:55:24,416 --> 09:55:25,416
and
13649
09:55:25,640 --> 09:55:26,640
CRC or cyclical redundancy check which
13650
09:55:29,520 --> 09:55:30,520
uses hashing a mathematical operation so
13651
09:55:32,340 --> 09:55:33,340
that we can ensure the data that was
13652
09:55:33,720 --> 09:55:34,720
received was also the data that was sent
13653
09:55:41,340 --> 09:55:42,340
[Music]
13654
09:55:58,140 --> 09:55:59,140
welcome to module 6 lesson 4A IPv6
13655
09:56:01,860 --> 09:56:02,860
Concepts
13656
09:56:04,860 --> 09:56:05,860
now we actually covered IPv6 earlier
13657
09:56:07,800 --> 09:56:08,800
however as per usual some new ideas have
13658
09:56:11,460 --> 09:56:12,460
been added to the syllabus so what I'll
13659
09:56:14,340 --> 09:56:15,340
do here is I'll review some areas that
13660
09:56:18,060 --> 09:56:19,060
you've already covered with Josh
13661
09:56:21,000 --> 09:56:22,000
with my own take and then we'll go into
13662
09:56:23,340 --> 09:56:24,340
the new stuff
13663
09:56:25,256 --> 09:56:26,256
so IPv6 addressing address types
13664
09:56:28,860 --> 09:56:29,860
new is a neighbor Discovery protocol
13665
09:56:31,500 --> 09:56:32,500
which is part of IPv6 built in
13666
09:56:34,980 --> 09:56:35,980
the eui 64 addressing is new
13667
09:56:38,820 --> 09:56:39,820
tunneling types is new
13668
09:56:43,200 --> 09:56:44,200
so ipv4 which is obviously the precursor
13669
09:56:45,960 --> 09:56:46,960
to IPv6 it created a long time before we
13670
09:56:49,860 --> 09:56:50,860
had home computers computers were pretty
13671
09:56:52,740 --> 09:56:53,740
expensive and big probably the size of
13672
09:56:55,200 --> 09:56:56,200
any room in your house
13673
09:56:57,000 --> 09:56:58,000
so no
13674
09:56:58,860 --> 09:56:59,860
um nobody foresaw that people would be
13675
09:57:00,900 --> 09:57:01,900
using
13676
09:57:01,916 --> 09:57:02,916
uh home computers just like when the
13677
09:57:04,200 --> 09:57:05,200
telephone was created I think uh one of
13678
09:57:06,900 --> 09:57:07,900
the first comments was why would I I
13679
09:57:09,000 --> 09:57:10,000
don't need to phone anyone
13680
09:57:10,800 --> 09:57:11,800
so uh there we go
13681
09:57:13,680 --> 09:57:14,680
uh so it was just the scheme was
13682
09:57:15,540 --> 09:57:16,540
designed just to cater for commercial
13683
09:57:17,340 --> 09:57:18,340
Enterprises only so we didn't think we
13684
09:57:19,740 --> 09:57:20,740
were going to run out
13685
09:57:21,180 --> 09:57:22,180
lack of a simple Auto configuration
13686
09:57:23,700 --> 09:57:24,700
mechanism so I eventually we had
13687
09:57:27,540 --> 09:57:28,540
um DHCP was uh created
13688
09:57:30,916 --> 09:57:31,916
which works well obviously it's got some
13689
09:57:33,540 --> 09:57:34,540
drawbacks
13690
09:57:35,580 --> 09:57:36,580
an ipv4 has no security built in again
13691
09:57:39,060 --> 09:57:40,060
nobody realized that
13692
09:57:41,400 --> 09:57:42,400
well there was no such thing as hackers
13693
09:57:43,380 --> 09:57:44,380
obviously when IP was brought out
13694
09:57:45,180 --> 09:57:46,180
because they hadn't been invented yet so
13695
09:57:47,220 --> 09:57:48,220
nobody thought that we needed to have it
13696
09:57:49,200 --> 09:57:50,200
built in
13697
09:57:50,416 --> 09:57:51,416
ipv4 is hard to use with mobile devices
13698
09:57:53,240 --> 09:57:54,240
especially when we're using the cellular
13699
09:57:55,680 --> 09:57:56,680
Networks
13700
09:57:59,300 --> 09:58:00,300
ipv4 needs massive writing tables
13701
09:58:01,800 --> 09:58:02,800
required over the internet internet
13702
09:58:03,120 --> 09:58:04,120
service providers have huge tables for
13703
09:58:06,000 --> 09:58:07,000
routing all the IP traffic
13704
09:58:08,580 --> 09:58:09,580
uh there's only around four million
13705
09:58:10,860 --> 09:58:11,860
addresses available we actually ran out
13706
09:58:12,840 --> 09:58:13,840
of ip4 addresses some time ago and
13707
09:58:15,240 --> 09:58:16,240
around 50 of the traffic going over the
13708
09:58:17,820 --> 09:58:18,820
internet at the moment is IPv6 which is
13709
09:58:20,520 --> 09:58:21,520
why yeah we need to know about it
13710
09:58:22,560 --> 09:58:23,560
so IPv6 uh there's that many addresses I
13711
09:58:25,740 --> 09:58:26,740
don't even know what the numbering
13712
09:58:27,596 --> 09:58:28,596
system is called for calling out that
13713
09:58:29,880 --> 09:58:30,880
many but for every person alive there's
13714
09:58:33,240 --> 09:58:34,240
many millions of available addresses now
13715
09:58:36,060 --> 09:58:37,060
and that can be used with IPv6 and
13716
09:58:38,340 --> 09:58:39,340
you'll read some documents about an app
13717
09:58:40,620 --> 09:58:41,620
PT not really used and there's no need
13718
09:58:44,756 --> 09:58:45,756
two and not because there's just no
13719
09:58:46,560 --> 09:58:47,560
shortage of addresses really security is
13720
09:58:49,436 --> 09:58:50,436
built into one of the fields in the IPv6
13721
09:58:51,720 --> 09:58:52,720
packet
13722
09:58:54,120 --> 09:58:55,120
we have addressed Auto configuration
13723
09:58:57,300 --> 09:58:58,300
which um is a major part of IPv6
13724
09:59:01,020 --> 09:59:02,020
and it's plug and play as well so things
13725
09:59:03,540 --> 09:59:04,540
like when you enable IPv6 on an
13726
09:59:05,580 --> 09:59:06,580
interface with most devices now it
13727
09:59:09,240 --> 09:59:10,240
actually self-configures an IPv6 address
13728
09:59:13,500 --> 09:59:14,500
we do not have broadcast and IPv6 we'll
13729
09:59:16,020 --> 09:59:17,020
come to that later
13730
09:59:17,700 --> 09:59:18,700
uh it's built to work plug and play with
13731
09:59:20,520 --> 09:59:21,520
mobile devices again which is Handy
13732
09:59:23,460 --> 09:59:24,460
so the address is there's several rfcs
13733
09:59:25,916 --> 09:59:26,916
one of the main ones is 1884 if you want
13734
09:59:28,800 --> 09:59:29,800
to read it it's a 128 bits each of these
13735
09:59:32,756 --> 09:59:33,756
bits is divided into into eight groups
13736
09:59:35,096 --> 09:59:36,096
of 16 bits and then each of those bits
13737
09:59:37,916 --> 09:59:38,916
is separated by a colon which is a DOT
13738
09:59:41,640 --> 09:59:42,640
on top of a dart
13739
09:59:43,200 --> 09:59:44,200
HEX number it is used because it's just
13740
09:59:45,660 --> 09:59:46,660
a lot easier to write out that many bits
13741
09:59:48,660 --> 09:59:49,660
using hex and it is in um binary it
13742
09:59:51,596 --> 09:59:52,596
would take forever
13743
09:59:53,096 --> 09:59:54,096
the address is when you're typing them
13744
09:59:54,660 --> 09:59:55,660
out on interfaces is not case sensitive
13745
09:59:56,820 --> 09:59:57,820
so you could use caps lock or lowercase
13746
09:59:59,460 --> 10:00:00,460
and the address will work fine and be
13747
10:00:01,680 --> 10:00:02,680
accepted
13748
10:00:02,820 --> 10:00:03,820
here is an example of an IPv6 and you
13749
10:00:06,060 --> 10:00:07,060
can see
13750
10:00:07,680 --> 10:00:08,680
if we just come over here
13751
10:00:09,776 --> 10:00:10,776
so eight groups of 16 bits which you'll
13752
10:00:12,180 --> 10:00:13,180
go into into a minute uh divided here by
13753
10:00:15,776 --> 10:00:16,776
the colon and another 16 bit 16 16 16 16
13754
10:00:21,620 --> 10:00:22,620
and so on
13755
10:00:29,416 --> 10:00:30,416
so if you wrote the address out in
13756
10:00:32,640 --> 10:00:33,640
binary just for the
13757
10:00:36,000 --> 10:00:37,000
I don't know why I should have said D
13758
10:00:38,276 --> 10:00:39,276
here sorry Eed e e d e
13759
10:00:43,860 --> 10:00:44,860
but if you change the hexadecimal here
13760
10:00:47,520 --> 10:00:48,520
so this is the hex
13761
10:00:49,560 --> 10:00:50,560
into the binary value it's one in the uh
13762
10:00:53,400 --> 10:00:54,400
if I go one
13763
10:00:55,500 --> 10:00:56,500
to I know you already know how um binary
13764
10:00:58,500 --> 10:00:59,500
works for eight so one in the eight
13765
10:01:02,096 --> 10:01:03,096
column one in the four one in the two so
13766
10:01:04,080 --> 10:01:05,080
eight plus four
13767
10:01:06,300 --> 10:01:07,300
uh it's twelve eight nine ten eleven
13768
10:01:09,596 --> 10:01:10,596
twelve thirteen at fourteen so the E is
13769
10:01:13,680 --> 10:01:14,680
number fourteen
13770
10:01:16,200 --> 10:01:17,200
here uh 14 here in HEX
13771
10:01:20,520 --> 10:01:21,520
now we've got the D so we've got uh one
13772
10:01:25,200 --> 10:01:26,200
plus four plus eight so eight nine ten
13773
10:01:29,936 --> 10:01:30,936
eleven twelve
13774
10:01:32,000 --> 10:01:33,000
thirteen so D is 13.
13775
10:01:36,660 --> 10:01:37,660
and then we're back to another 14. 16
13776
10:01:39,596 --> 10:01:40,596
bits two bytes in total so four bits
13777
10:01:43,500 --> 10:01:44,500
uh four bits eight and then another
13778
10:01:45,720 --> 10:01:46,720
eight 16 bits so that's two bytes
13779
10:01:50,040 --> 10:01:51,040
we can compress the address
13780
10:01:52,560 --> 10:01:53,560
so you can remove the leading zeros
13781
10:01:54,980 --> 10:01:55,980
leading zeros are numbers that appear
13782
10:01:58,980 --> 10:01:59,980
before and so this is a leading zero
13783
10:02:02,416 --> 10:02:03,416
leading zero this is a trailing zero so
13784
10:02:06,180 --> 10:02:07,180
we can't remove these because they've
13785
10:02:08,520 --> 10:02:09,520
got numbers uh prior just before so if
13786
10:02:12,776 --> 10:02:13,776
we get rid of the leading zeros for
13787
10:02:15,540 --> 10:02:16,540
example here zero zero zero one becomes
13788
10:02:18,960 --> 10:02:19,960
a one
13789
10:02:20,220 --> 10:02:21,220
zero seven eight nine becomes seven
13790
10:02:22,380 --> 10:02:23,380
eight nine and this is uh to save space
13791
10:02:26,220 --> 10:02:27,220
and for when we're writing out the
13792
10:02:27,900 --> 10:02:28,900
address is zero ABC becomes ABC and you
13793
10:02:31,380 --> 10:02:32,380
can get rid of the trailing zeros here
13794
10:02:33,180 --> 10:02:34,180
and just have one zero so this address
13795
10:02:35,400 --> 10:02:36,400
is uh legal
13796
10:02:39,000 --> 10:02:40,000
to write that out you could possibly
13797
10:02:40,680 --> 10:02:41,680
have questions in the exam uh asking you
13798
10:02:43,140 --> 10:02:44,140
to choose the correct compressed address
13799
10:02:45,660 --> 10:02:46,660
you can use a double colon
13800
10:02:48,500 --> 10:02:49,500
wants to represent consecutive zeros so
13801
10:02:52,140 --> 10:02:53,140
here we go we've got all these
13802
10:02:54,660 --> 10:02:55,660
consecutive zeros here for some reason
13803
10:02:56,936 --> 10:02:57,936
well we've got rid of them just by
13804
10:02:59,460 --> 10:03:00,460
having the double curl on here
13805
10:03:02,340 --> 10:03:03,340
and we've got a double coal on here
13806
10:03:04,320 --> 10:03:05,320
between the one two three four
13807
10:03:06,596 --> 10:03:07,596
so what we've done is just compress all
13808
10:03:09,000 --> 10:03:10,000
of these zeros and we've done it again
13809
10:03:11,460 --> 10:03:12,460
here
13810
10:03:15,180 --> 10:03:16,180
and then just to we could have put it in
13811
10:03:17,880 --> 10:03:18,880
the second set of zeros but just to save
13812
10:03:19,916 --> 10:03:20,916
space we've got rid of all these zeros
13813
10:03:22,436 --> 10:03:23,436
here
13814
10:03:23,700 --> 10:03:24,700
so practice this work out your own
13815
10:03:26,220 --> 10:03:27,220
numbers because this is a typical exam
13816
10:03:28,200 --> 10:03:29,200
type question
13817
10:03:29,520 --> 10:03:30,520
main
13818
10:03:30,800 --> 10:03:31,800
IPv6 address types Global unicast unique
13819
10:03:34,436 --> 10:03:35,436
local link local and multicast you'll
13820
10:03:37,800 --> 10:03:38,800
note we don't have broadcast that isn't
13821
10:03:39,540 --> 10:03:40,540
a legal address and we also have any
13822
10:03:41,580 --> 10:03:42,580
cast which I'm not sure if I mentioned
13823
10:03:43,140 --> 10:03:44,140
here
13824
10:03:44,520 --> 10:03:45,520
so the global unicast the this is
13825
10:03:47,400 --> 10:03:48,400
allocated by the ISP and then you will
13826
10:03:49,620 --> 10:03:50,620
get a mask Associated whatever the mask
13827
10:03:52,436 --> 10:03:53,436
may be
13828
10:03:56,700 --> 10:03:57,700
these are routable on the internet so
13829
10:03:58,800 --> 10:03:59,800
you can send them out of your company
13830
10:04:02,756 --> 10:04:03,756
and um
13831
10:04:04,560 --> 10:04:05,560
they're legal they're legally recognized
13832
10:04:07,800 --> 10:04:08,800
the numbers range from 2000 to 3 FFF in
13833
10:04:11,340 --> 10:04:12,340
the first 16 bits
13834
10:04:15,060 --> 10:04:16,060
current allocation there's there's
13835
10:04:17,340 --> 10:04:18,340
trillions of these addresses so the
13836
10:04:18,840 --> 10:04:19,840
current allocation has come in from
13837
10:04:21,020 --> 10:04:22,020
2001. this will this will last quite
13838
10:04:23,400 --> 10:04:24,400
some time obviously
13839
10:04:25,500 --> 10:04:26,500
there's a 48-bit provider prefix and if
13840
10:04:29,096 --> 10:04:30,096
you uh check the
13841
10:04:30,660 --> 10:04:31,660
images of the address packet you'll see
13842
10:04:34,740 --> 10:04:35,740
the 48-bit uh there's a subnet ID
13843
10:04:38,880 --> 10:04:39,880
you can submit inside the organization
13844
10:04:40,800 --> 10:04:41,800
if you wish subnet to IPv6 is a topic
13845
10:04:44,580 --> 10:04:45,580
but it's not in the CompTIA it is in the
13846
10:04:47,520 --> 10:04:48,520
Cisco ctna and then the rest is the host
13847
10:04:50,936 --> 10:04:51,936
portion of the address
13848
10:04:54,840 --> 10:04:55,840
now I'm sure most equipment can actually
13849
10:04:57,720 --> 10:04:58,720
do this but Cisco routers can
13850
10:04:59,520 --> 10:05:00,520
self-generate this part here
13851
10:05:02,820 --> 10:05:03,820
so what you would do is if you configure
13852
10:05:04,680 --> 10:05:05,680
an interface you would you would
13853
10:05:06,240 --> 10:05:07,240
basically configure whatever the address
13854
10:05:07,980 --> 10:05:08,980
is
13855
10:05:10,680 --> 10:05:11,680
dot b dot whatever whatever and then the
13856
10:05:13,200 --> 10:05:14,200
host portion here the interface would
13857
10:05:17,340 --> 10:05:18,340
um self-configure
13858
10:05:21,060 --> 10:05:22,060
so
13859
10:05:24,960 --> 10:05:25,960
um I've issued oh this is on my um
13860
10:05:27,720 --> 10:05:28,720
Windows computer for the looks of it
13861
10:05:29,340 --> 10:05:30,340
I've just issued an IP config or
13862
10:05:36,180 --> 10:05:37,180
forward slash all and I've seen the IPv6
13863
10:05:39,416 --> 10:05:40,416
address that's been allocated here and I
13864
10:05:42,900 --> 10:05:43,900
think Windows self-allocates these
13865
10:05:44,700 --> 10:05:45,700
addresses also
13866
10:05:47,416 --> 10:05:48,416
uh link local address the prefix for
13867
10:05:50,400 --> 10:05:51,400
link local addresses are feat these are
13868
10:05:53,700 --> 10:05:54,700
only valid between the link between two
13869
10:05:55,380 --> 10:05:56,380
IB V6 interfaces so you've got an
13870
10:05:58,620 --> 10:05:59,620
internal router and say for example an
13871
10:06:01,680 --> 10:06:02,680
ethernet connection here
13872
10:06:03,540 --> 10:06:04,540
then these addresses will be valid and
13873
10:06:06,596 --> 10:06:07,596
these two IPv6 routers
13874
10:06:12,660 --> 10:06:13,660
can communicate with one another using
13875
10:06:15,300 --> 10:06:16,300
this link local address what it can't do
13876
10:06:17,820 --> 10:06:18,820
is this address in here it can't be used
13877
10:06:20,460 --> 10:06:21,460
to reach another device out here
13878
10:06:24,000 --> 10:06:25,000
now if you've got another device the
13879
10:06:26,096 --> 10:06:27,096
link local addresses of these two facing
13880
10:06:29,340 --> 10:06:30,340
interfaces so for example fast ethernet
13881
10:06:31,740 --> 10:06:32,740
here fast ethernet here they will
13882
10:06:34,500 --> 10:06:35,500
communicate between one another here
13883
10:06:38,720 --> 10:06:39,720
automatically created once IPv6 is
13884
10:06:41,640 --> 10:06:42,640
enabled
13885
10:06:43,436 --> 10:06:44,436
now these are used for writing protocol
13886
10:06:45,360 --> 10:06:46,360
Communications IPv6 protocols mentioned
13887
10:06:48,596 --> 10:06:49,596
in the syllabus but I don't think I've
13888
10:06:50,700 --> 10:06:51,700
left it out for now because looking at
13889
10:06:52,256 --> 10:06:53,256
all the official guides there's no um
13890
10:06:55,680 --> 10:06:56,680
questions yet I will add it later on if
13891
10:06:58,740 --> 10:06:59,740
um if that changes though
13892
10:07:01,916 --> 10:07:02,916
traffic isn't forwarded off the local
13893
10:07:03,660 --> 10:07:04,660
link certainly not using the link local
13894
10:07:05,880 --> 10:07:06,880
address
13895
10:07:07,800 --> 10:07:08,800
so here's a configuration for a Cisco
13896
10:07:10,140 --> 10:07:11,140
router you I've enabled IPv6 routing
13897
10:07:13,740 --> 10:07:14,740
I've gone to the faster ethernet
13898
10:07:15,540 --> 10:07:16,540
interface all I've done is turned on
13899
10:07:18,480 --> 10:07:19,480
IPv6 for this interface here the fast
13900
10:07:21,540 --> 10:07:22,540
ethernet zero slash zero
13901
10:07:23,700 --> 10:07:24,700
I've typed end and then it I've said
13902
10:07:26,096 --> 10:07:27,096
show me this interface it's down I
13903
10:07:28,620 --> 10:07:29,620
haven't connected it to anything but as
13904
10:07:31,380 --> 10:07:32,380
we can see this address this link local
13905
10:07:33,840 --> 10:07:34,840
address has been allocated
13906
10:07:36,020 --> 10:07:37,020
self-allocated this is an important bit
13907
10:07:38,756 --> 10:07:39,756
here
13908
10:07:40,140 --> 10:07:41,140
FFF as we'll see in a minute but
13909
10:07:42,480 --> 10:07:43,480
basically this is my IPv6 address I have
13910
10:07:45,480 --> 10:07:46,480
an app to write it out manually at all
13911
10:07:51,480 --> 10:07:52,480
I've already um shown you the windows
13912
10:07:53,340 --> 10:07:54,340
one
13913
10:07:54,416 --> 10:07:55,416
yeah unique local uh it's the IPv6
13914
10:07:57,540 --> 10:07:58,540
version of private IP addresses so you
13915
10:07:59,640 --> 10:08:00,640
can use all of these on the inside of
13916
10:08:01,800 --> 10:08:02,800
your network you wouldn't be able to
13917
10:08:03,300 --> 10:08:04,300
Route them onto the internet don't think
13918
10:08:05,640 --> 10:08:06,640
these are used anymore I think they're
13919
10:08:06,900 --> 10:08:07,900
actually been depreciated
13920
10:08:10,140 --> 10:08:11,140
if you get a question in the exam here
13921
10:08:12,240 --> 10:08:13,240
it would be something like this what
13922
10:08:13,680 --> 10:08:14,680
prefixes link local addresses are taken
13923
10:08:16,500 --> 10:08:17,500
from fc00
13924
10:08:18,320 --> 10:08:19,320
uh forward slash seven for your subnet
13925
10:08:21,480 --> 10:08:22,480
mask
13926
10:08:23,360 --> 10:08:24,360
these depreciate site local addresses oh
13927
10:08:26,096 --> 10:08:27,096
sorry so site local addresses that have
13928
10:08:28,320 --> 10:08:29,320
been depreciated and overtaken by link
13929
10:08:31,380 --> 10:08:32,380
local a unique local so you'd use this
13930
10:08:34,436 --> 10:08:35,436
on the inside of your network if you
13931
10:08:35,820 --> 10:08:36,820
want to do any internal routing what you
13932
10:08:38,040 --> 10:08:39,040
couldn't do is use it out on your on the
13933
10:08:40,020 --> 10:08:41,020
internet though
13934
10:08:41,756 --> 10:08:42,756
multicast addresses are still used very
13935
10:08:44,040 --> 10:08:45,040
much in IPv6 this is the prefix so write
13936
10:08:49,560 --> 10:08:50,560
it down and put it into your studying
13937
10:08:51,360 --> 10:08:52,360
crumb notes
13938
10:08:53,160 --> 10:08:54,160
and multicast replaces address
13939
10:08:54,900 --> 10:08:55,900
resolution protocol for IPv6
13940
10:08:59,460 --> 10:09:00,460
a use for duplicate address detection so
13941
10:09:02,400 --> 10:09:03,400
when you first fire up your interface
13942
10:09:06,120 --> 10:09:07,120
I'll talk about neighbor Discovery in a
13943
10:09:08,276 --> 10:09:09,276
moment but I'll say just to save space
13944
10:09:11,340 --> 10:09:12,340
I'll say this is the address obviously
13945
10:09:13,620 --> 10:09:14,620
it would be the IPv6 address it will
13946
10:09:16,256 --> 10:09:17,256
this interface will advertise out this
13947
10:09:17,880 --> 10:09:18,880
address
13948
10:09:19,080 --> 10:09:20,080
to um
13949
10:09:21,240 --> 10:09:22,240
the network this multicast address
13950
10:09:25,320 --> 10:09:26,320
saying I want to use this address X and
13951
10:09:27,540 --> 10:09:28,540
if any of the any of these interfaces
13952
10:09:30,120 --> 10:09:31,120
are using that address so this is using
13953
10:09:32,460 --> 10:09:33,460
Y that's using Zed
13954
10:09:34,800 --> 10:09:35,800
it will come back and say no you can't
13955
10:09:36,480 --> 10:09:37,480
use that address but in this case my
13956
10:09:38,220 --> 10:09:39,220
example here nobody's using it
13957
10:09:41,340 --> 10:09:42,340
all routers must join the All host
13958
10:09:43,620 --> 10:09:44,620
multicast group of
13959
10:09:46,040 --> 10:09:47,040
ff02 and then whatever in the middle uh
13960
10:09:49,680 --> 10:09:50,680
one so it'll all be zeros and then one
13961
10:09:52,020 --> 10:09:53,020
and the all routers multicast group this
13962
10:09:54,900 --> 10:09:55,900
is how enable Discovery protocol works
13963
10:09:56,756 --> 10:09:57,756
so it must be allocated and listening to
13964
10:09:58,980 --> 10:09:59,980
these two addresses
13965
10:10:00,540 --> 10:10:01,540
and if I issue a show IPv6 interface
13966
10:10:04,916 --> 10:10:05,916
fast ethernet 0 0 you can say you can
13967
10:10:08,276 --> 10:10:09,276
see that it's joined these two groups
13968
10:10:10,560 --> 10:10:11,560
appear the um the F2 and the F1
13969
10:10:16,916 --> 10:10:17,916
eui 64 addressing is the new part in the
13970
10:10:21,240 --> 10:10:22,240
syllabus
13971
10:10:23,700 --> 10:10:24,700
yeah so I've issued a show ipv
13972
10:10:26,540 --> 10:10:27,540
IP interface sorry I've didn't do IPv6
13973
10:10:30,740 --> 10:10:31,740
because I want to see what the MAC
13974
10:10:33,720 --> 10:10:34,720
address is
13975
10:10:35,640 --> 10:10:36,640
because this is how eui 64 obtains the
13976
10:10:40,500 --> 10:10:41,500
um eui 64 address
13977
10:10:43,380 --> 10:10:44,380
so this is how or one of the ways you
13978
10:10:45,960 --> 10:10:46,960
can self generate an interface it uses
13979
10:10:48,060 --> 10:10:49,060
the MAC address
13980
10:10:50,276 --> 10:10:51,276
the 48-bit MAC address obviously we need
13981
10:10:53,040 --> 10:10:54,040
128 bits 48 bits isn't enough to
13982
10:10:56,460 --> 10:10:57,460
generate this address
13983
10:10:58,800 --> 10:10:59,800
but what it does it takes the MAC
13984
10:11:00,180 --> 10:11:01,180
address
13985
10:11:01,256 --> 10:11:02,256
it inverts the seventh bit and adds FFF
13986
10:11:05,400 --> 10:11:06,400
Fe in the center so right in the middle
13987
10:11:08,820 --> 10:11:09,820
of the MAC address it's going to add
13988
10:11:12,620 --> 10:11:13,620
fffe make sure you take a note of this
13989
10:11:15,500 --> 10:11:16,500
for the exam so
13990
10:11:17,880 --> 10:11:18,880
uh we've got zero zero one one
13991
10:11:22,436 --> 10:11:23,436
hold cover white it doesn't say zero
13992
10:11:24,840 --> 10:11:25,840
zero one one here and then here's the a
13993
10:11:29,220 --> 10:11:30,220
here
13994
10:11:30,840 --> 10:11:31,840
and then you can see the fffe has
13995
10:11:33,416 --> 10:11:34,416
appeared he has inserted it and then it
13996
10:11:36,840 --> 10:11:37,840
carries on with the rest of the MAC
13997
10:11:37,916 --> 10:11:38,916
address BB c c d d so b b c c c m c d so
13998
10:11:43,680 --> 10:11:44,680
this is how it pads out the address
13999
10:11:47,096 --> 10:11:48,096
so there's two bits Mac address
14000
10:11:51,120 --> 10:11:52,120
plus this but then it does this other
14001
10:11:54,120 --> 10:11:55,120
bit here which is inverting the seventh
14002
10:11:56,340 --> 10:11:57,340
bit
14003
10:11:59,096 --> 10:12:00,096
so
14004
10:12:00,900 --> 10:12:01,900
just to recap what I've already said
14005
10:12:02,580 --> 10:12:03,580
we're looking at this part now zero zero
14006
10:12:05,520 --> 10:12:06,520
one one well instead of that now we've
14007
10:12:07,916 --> 10:12:08,916
got zero two one one
14008
10:12:16,080 --> 10:12:17,080
all right so going into the seventh
14009
10:12:17,936 --> 10:12:18,936
seventh most significant bit
14010
10:12:21,596 --> 10:12:22,596
so this is our sample address here
14011
10:12:25,560 --> 10:12:26,560
the first two nibbles uh or is one byte
14012
10:12:29,400 --> 10:12:30,400
so this is 0.0 so a nibble if we have
14013
10:12:34,140 --> 10:12:35,140
one two three four five six seven eight
14014
10:12:38,160 --> 10:12:39,160
so eight bits is one byte which we've
14015
10:12:40,980 --> 10:12:41,980
covered already oops
14016
10:12:43,680 --> 10:12:44,680
one byte
14017
10:12:46,020 --> 10:12:47,020
one byte eight bits but what we can do
14018
10:12:49,860 --> 10:12:50,860
is kind of subdivide it in the middle
14019
10:12:51,480 --> 10:12:52,480
here
14020
10:12:54,180 --> 10:12:55,180
and we can have a nibble here
14021
10:12:58,500 --> 10:12:59,500
and a nibble here
14022
10:13:03,416 --> 10:13:04,416
all right so our first two nibbles one
14023
10:13:06,300 --> 10:13:07,300
byte here
14024
10:13:07,800 --> 10:13:08,800
is zero zero
14025
10:13:10,256 --> 10:13:11,256
which would have all the binary bits
14026
10:13:12,360 --> 10:13:13,360
basically pretty easy to work out
14027
10:13:17,276 --> 10:13:18,276
so this here
14028
10:13:19,800 --> 10:13:20,800
if you write it out with a nice uh
14029
10:13:22,256 --> 10:13:23,256
font is zero zero zero zero zero zero
14030
10:13:25,380 --> 10:13:26,380
zero zero so what we need to do is flip
14031
10:13:28,020 --> 10:13:29,020
the seventh most significant bit
14032
10:13:31,560 --> 10:13:32,560
so what we've done is one two three four
14033
10:13:36,000 --> 10:13:37,000
five six seven eight so this is the
14034
10:13:40,320 --> 10:13:41,320
seventh most significant bit and what
14035
10:13:42,660 --> 10:13:43,660
we've done is gone all the way over here
14036
10:13:44,520 --> 10:13:45,520
to find the seventh bit and we've
14037
10:13:46,740 --> 10:13:47,740
flipped it so whatever it was here in
14038
10:13:49,256 --> 10:13:50,256
binary we flipped it so one
14039
10:13:53,756 --> 10:13:54,756
flip two
14040
10:13:58,256 --> 10:13:59,256
sorry zero flip to be a one
14041
10:14:02,460 --> 10:14:03,460
now if you wrote that out uh this part
14042
10:14:05,276 --> 10:14:06,276
here
14043
10:14:06,660 --> 10:14:07,660
you'd have um
14044
10:14:08,700 --> 10:14:09,700
your zero would be covered two that's
14045
10:14:10,916 --> 10:14:11,916
the one two four eight one two four
14046
10:14:16,620 --> 10:14:17,620
eight Okay so we've uh enabled this
14047
10:14:20,040 --> 10:14:21,040
column here and our zero has flipped to
14048
10:14:22,860 --> 10:14:23,860
A2
14049
10:14:26,276 --> 10:14:27,276
and you can see here zero two one one
14050
10:14:29,276 --> 10:14:30,276
and then um this is the MAC address
14051
10:14:31,256 --> 10:14:32,256
we've got the fffe in the middle and
14052
10:14:34,080 --> 10:14:35,080
then the rest of the MAC address this is
14053
10:14:35,880 --> 10:14:36,880
how you work it out you might get a
14054
10:14:37,320 --> 10:14:38,320
question on this so this is why I
14055
10:14:39,000 --> 10:14:40,000
brought it to uh your attention and you
14056
10:14:41,400 --> 10:14:42,400
just need to practice a few examples
14057
10:14:44,700 --> 10:14:45,700
so what would this address be changed to
14058
10:14:47,340 --> 10:14:48,340
if you write it down
14059
10:14:53,756 --> 10:14:54,756
all right so I've just carried it over
14060
10:14:55,140 --> 10:14:56,140
to the next slide here
14061
10:15:00,980 --> 10:15:01,980
so Charlotte IPv6 interface we've got
14062
10:15:04,256 --> 10:15:05,256
this address here and we end up with
14063
10:15:08,040 --> 10:15:09,040
this global unicass address here
14064
10:15:11,040 --> 10:15:12,040
and you can see already we've got the
14065
10:15:13,560 --> 10:15:14,560
fffe
14066
10:15:15,180 --> 10:15:16,180
created here
14067
10:15:16,916 --> 10:15:17,916
so and because it's it might not show
14068
10:15:19,980 --> 10:15:20,980
you another
14069
10:15:20,840 --> 10:15:21,840
vendors but you can see here there's a
14070
10:15:23,520 --> 10:15:24,520
clue it says eui so we know eui 64 is
14071
10:15:26,700 --> 10:15:27,700
addressing
14072
10:15:27,960 --> 10:15:28,960
well C2 in decimal is 192.
14073
10:15:32,276 --> 10:15:33,276
or um in binary here one one zero zero
14074
10:15:36,480 --> 10:15:37,480
double one double zero in hexadecimal is
14075
10:15:40,740 --> 10:15:41,740
C
14076
10:15:41,820 --> 10:15:42,820
and if you've just got a one in the uh
14077
10:15:44,580 --> 10:15:45,580
two the two column here so one two four
14078
10:15:48,840 --> 10:15:49,840
eight you can see uh that's a two
14079
10:15:53,160 --> 10:15:54,160
see in hexadecimal is 12 so we've got 8
14080
10:15:57,060 --> 10:15:58,060
9 10 11 12. so I think we've covered hex
14081
10:16:00,720 --> 10:16:01,720
earlier so you swap the seventh bit
14082
10:16:04,020 --> 10:16:05,020
so one two three four five six seven
14083
10:16:08,520 --> 10:16:09,520
this bit has to be swapped if we're
14084
10:16:10,680 --> 10:16:11,680
doing the UI 64.
14085
10:16:13,256 --> 10:16:14,256
and then it becomes a zero if you work
14086
10:16:16,500 --> 10:16:17,500
this out zero zero zero zero the second
14087
10:16:19,200 --> 10:16:20,200
part is uh C zero so here we go c0 and
14088
10:16:25,020 --> 10:16:26,020
then it carries on as normal zero zero
14089
10:16:27,240 --> 10:16:28,240
instead of C2
14090
10:16:29,160 --> 10:16:30,160
so I know it's a lot to get your head
14091
10:16:30,960 --> 10:16:31,960
around just practice it watch this over
14092
10:16:32,756 --> 10:16:33,756
a few times and then practice some of
14093
10:16:34,256 --> 10:16:35,256
your own examples
14094
10:16:36,776 --> 10:16:37,776
applying it enter your desired subnet
14095
10:16:39,060 --> 10:16:40,060
and then add the command the tag eui 64.
14096
10:16:43,320 --> 10:16:44,320
this is how you do it in Cisco you won't
14097
10:16:45,240 --> 10:16:46,240
be asked about vendors or how to apply
14098
10:16:47,640 --> 10:16:48,640
it I'm sure I'm just telling you how it
14099
10:16:49,080 --> 10:16:50,080
works so I've added this address I want
14100
10:16:52,200 --> 10:16:53,200
to say we're using um
14101
10:16:54,540 --> 10:16:55,540
this subnet here this address and uh
14102
10:16:59,040 --> 10:17:00,040
double colon so I don't care what goes
14103
10:17:02,220 --> 10:17:03,220
there
14104
10:17:03,020 --> 10:17:04,020
64 and then I add the tag basically
14105
10:17:05,756 --> 10:17:06,756
saying you um you allocate
14106
10:17:11,180 --> 10:17:12,180
uh using the MAC address plus the
14107
10:17:15,840 --> 10:17:16,840
seventh
14108
10:17:18,300 --> 10:17:19,300
bit rule which will swap the seventh
14109
10:17:21,360 --> 10:17:22,360
most significant bit from a zero to one
14110
10:17:23,756 --> 10:17:24,756
or one to a zero
14111
10:17:30,120 --> 10:17:31,120
and here's the command on an actual
14112
10:17:31,860 --> 10:17:32,860
router so yeah you have to you can't
14113
10:17:34,020 --> 10:17:35,020
just say create the entire address for
14114
10:17:36,300 --> 10:17:37,300
the routable address
14115
10:17:38,756 --> 10:17:39,756
um you have to add this tag here
14116
10:17:43,460 --> 10:17:44,460
all right next is the neighbor Discovery
14117
10:17:46,320 --> 10:17:47,320
protocol which is a major feature of uh
14118
10:17:49,320 --> 10:17:50,320
of IPv6 this allows other routers on the
14119
10:17:53,340 --> 10:17:54,340
link to be discovered there's a couple
14120
10:17:54,960 --> 10:17:55,960
of messages you you need to be aware of
14121
10:17:56,936 --> 10:17:57,936
which is RS router solicitation like are
14122
10:18:01,500 --> 10:18:02,500
are any routers on the link this is the
14123
10:18:04,020 --> 10:18:05,020
router solicitation message
14124
10:18:06,240 --> 10:18:07,240
and it's sent out saying what what else
14125
10:18:08,220 --> 10:18:09,220
is here
14126
10:18:10,140 --> 10:18:11,140
the router advertisement is the reply
14127
10:18:13,740 --> 10:18:14,740
you'll get from the routers IPv6 routers
14128
10:18:17,400 --> 10:18:18,400
uh yep I'm here R A I'm here
14129
10:18:23,040 --> 10:18:24,040
it just give us prefixes so whatever
14130
10:18:25,436 --> 10:18:26,436
your prefix is on the network
14131
10:18:33,180 --> 10:18:34,180
Etc these routers will say we're using
14132
10:18:36,000 --> 10:18:37,000
this prefix and then this will be able
14133
10:18:38,276 --> 10:18:39,276
to Auto allocate an address so it can
14134
10:18:40,620 --> 10:18:41,620
communicate communicate on the subnet
14135
10:18:44,160 --> 10:18:45,160
so this replaces our we don't have ARP
14136
10:18:46,980 --> 10:18:47,980
working on the uh on IPv6 subnets
14137
10:18:51,660 --> 10:18:52,660
also works to duplicate address
14138
10:18:53,460 --> 10:18:54,460
detection which I've already mentioned
14139
10:18:55,200 --> 10:18:56,200
the device the ipvx ibv6 device will say
14140
10:18:58,980 --> 10:18:59,980
I want to use address X are any of you
14141
10:19:01,680 --> 10:19:02,680
using it and then there'll be a reply if
14142
10:19:03,840 --> 10:19:04,840
it is in use
14143
10:19:06,960 --> 10:19:07,960
so there was solicitation asking for a
14144
10:19:09,720 --> 10:19:10,720
neighbor's information
14145
10:19:11,520 --> 10:19:12,520
their neighbor advertisement you
14146
10:19:13,080 --> 10:19:14,080
advertise yourself out to Neighbors
14147
10:19:16,256 --> 10:19:17,256
the solicitation asks for information
14148
10:19:18,660 --> 10:19:19,660
about local routers these are the four
14149
10:19:20,520 --> 10:19:21,520
types that you need to know about router
14150
10:19:22,916 --> 10:19:23,916
advertisement advertise yourself as
14151
10:19:24,720 --> 10:19:25,720
active these are the four types so make
14152
10:19:26,700 --> 10:19:27,700
a note of them
14153
10:19:29,640 --> 10:19:30,640
the idea I've already mentioned the
14154
10:19:31,500 --> 10:19:32,500
neighbor advertisements are sent to
14155
10:19:33,060 --> 10:19:34,060
check if your address is unique this is
14156
10:19:35,700 --> 10:19:36,700
the address it's sent to which is the um
14157
10:19:38,640 --> 10:19:39,640
save as a broadcast address but we're
14158
10:19:40,200 --> 10:19:41,200
multi-cat we're multicasting in IPv6
14159
10:19:44,936 --> 10:19:45,936
no reply means your address is available
14160
10:19:46,916 --> 10:19:47,916
to use the amount of air seconds
14161
10:19:52,380 --> 10:19:53,380
should vary from vendor to vendor I
14162
10:19:54,360 --> 10:19:55,360
haven't read the RFC actually but if you
14163
10:19:56,580 --> 10:19:57,580
really wanted to you can read it
14164
10:19:59,960 --> 10:20:00,960
so you can see the advertisement is
14165
10:20:02,700 --> 10:20:03,700
going out with this address reply if you
14166
10:20:05,096 --> 10:20:06,096
are this address
14167
10:20:07,200 --> 10:20:08,200
using the icmpv6 packet
14168
10:20:11,340 --> 10:20:12,340
um and then the
14169
10:20:13,916 --> 10:20:14,916
advertisement here I am this address so
14170
10:20:16,800 --> 10:20:17,800
basically you can't use it
14171
10:20:20,480 --> 10:20:21,480
DHCP version 6 is used for IPv6 this is
14172
10:20:25,140 --> 10:20:26,140
for auto allocation of addresses
14173
10:20:27,660 --> 10:20:28,660
also used with uh it's used in
14174
10:20:29,936 --> 10:20:30,936
conjunction with DNS for IPv6
14175
10:20:33,416 --> 10:20:34,416
and here's the RSC if you've got some
14176
10:20:35,880 --> 10:20:36,880
spare time in your hands allocate IPv6
14177
10:20:38,936 --> 10:20:39,936
information to hose obviously the IPv6
14178
10:20:42,660 --> 10:20:43,660
is um
14179
10:20:46,800 --> 10:20:47,800
the Gateway the the DNS server
14180
10:20:50,880 --> 10:20:51,880
and another DHCP information
14181
10:20:55,560 --> 10:20:56,560
host can request it with an outgoing
14182
10:20:57,360 --> 10:20:58,360
router advertisement message
14183
10:21:00,416 --> 10:21:01,416
allocated and requested using UDP bear
14184
10:21:03,120 --> 10:21:04,120
that in mind because some people think
14185
10:21:04,380 --> 10:21:05,380
it's TCP it's Port 546 and 547
14186
10:21:10,500 --> 10:21:11,500
the other subject you need to be aware
14187
10:21:12,660 --> 10:21:13,660
of now is if you're running uh IPv6 on
14188
10:21:18,120 --> 10:21:19,120
your network and then ipv4 nobody is
14189
10:21:21,120 --> 10:21:22,120
going to
14190
10:21:22,020 --> 10:21:23,020
come into work one day and have ipv4
14191
10:21:25,820 --> 10:21:26,820
taken off and only even in IPv6 you're
14192
10:21:29,520 --> 10:21:30,520
going to have a transition period where
14193
10:21:31,620 --> 10:21:32,620
you're running both of these protocols
14194
10:21:33,900 --> 10:21:34,900
so what's going to happen is somehow
14195
10:21:35,900 --> 10:21:36,900
IPv6 host reaches an ipv4 router and
14196
10:21:40,800 --> 10:21:41,800
what you're going to have to do
14197
10:21:43,500 --> 10:21:44,500
is tunnel the IPv6
14198
10:21:46,936 --> 10:21:47,936
information inside
14199
10:21:51,240 --> 10:21:52,240
an ipv4 packet with a header and the
14200
10:21:55,916 --> 10:21:56,916
trailer running ipv4
14201
10:21:59,340 --> 10:22:00,340
there's a few versions isotap
14202
10:22:02,400 --> 10:22:03,400
uh
14203
10:22:03,900 --> 10:22:04,900
64 to the link
14204
10:22:06,060 --> 10:22:07,060
dual stack is when you're running both
14205
10:22:07,916 --> 10:22:08,916
at the same time
14206
10:22:09,960 --> 10:22:10,960
there's a static to null I think yeah
14207
10:22:13,020 --> 10:22:14,020
that's different to GRE you don't have
14208
10:22:15,240 --> 10:22:16,240
to know the config so don't worry about
14209
10:22:16,740 --> 10:22:17,740
it generic routing encapsulation has
14210
10:22:18,900 --> 10:22:19,900
been around a long time but you can use
14211
10:22:20,820 --> 10:22:21,820
that for tunnel in
14212
10:22:23,180 --> 10:22:24,180
automatic as another type you can choose
14213
10:22:26,700 --> 10:22:27,700
from
14214
10:22:28,320 --> 10:22:29,320
if you want to study more I recommend
14215
10:22:30,180 --> 10:22:31,180
everyone needs to do about
14216
10:22:33,000 --> 10:22:34,000
uh four hours
14217
10:22:35,460 --> 10:22:36,460
studying to IPv6 this is for interviews
14218
10:22:40,276 --> 10:22:41,276
technical jobs uh technical interviews
14219
10:22:43,980 --> 10:22:44,980
and just to do your day-to-day job you
14220
10:22:46,500 --> 10:22:47,500
do need to understand it there's a
14221
10:22:48,660 --> 10:22:49,660
course on them cartoon network.com it's
14222
10:22:51,660 --> 10:22:52,660
16 hours in total but I broke it down
14223
10:22:53,820 --> 10:22:54,820
into I think the beginner course is
14224
10:22:55,800 --> 10:22:56,800
about three there's an intermediate with
14225
10:22:58,500 --> 10:22:59,500
loads of routing
14226
10:23:00,120 --> 10:23:01,120
and then maybe I think five or I'm
14227
10:23:03,840 --> 10:23:04,840
trying to do my math now six to 12.
14228
10:23:06,300 --> 10:23:07,300
seven hours extra which is Advanced so
14229
10:23:09,960 --> 10:23:10,960
you could just do one part and then when
14230
10:23:11,936 --> 10:23:12,936
you come to do something a bit more
14231
10:23:13,140 --> 10:23:14,140
difficult do the second part and if you
14232
10:23:15,060 --> 10:23:16,060
want the third but um you really do need
14233
10:23:17,580 --> 10:23:18,580
to know IPv6 I've been talking about
14234
10:23:19,320 --> 10:23:20,320
this for about four years now and it's
14235
10:23:22,436 --> 10:23:23,436
becoming more and more urgent so you I
14236
10:23:24,900 --> 10:23:25,900
used to recommend it and now basically
14237
10:23:26,700 --> 10:23:27,700
the the level of uh understanding in the
14238
10:23:30,120 --> 10:23:31,120
the level of adoption is basically you
14239
10:23:31,916 --> 10:23:32,916
you have to know it it's just like not
14240
10:23:34,200 --> 10:23:35,200
knowing ipv4 now if you go into it um if
14241
10:23:36,900 --> 10:23:37,900
you go into an interview so please do
14242
10:23:39,060 --> 10:23:40,060
learn it and we've covered IPv6 address
14243
10:23:42,960 --> 10:23:43,960
types Navy Discovery eui 64 and then
14244
10:23:47,460 --> 10:23:48,460
tunnel in that's all for now thanks for
14245
10:23:49,560 --> 10:23:50,560
listening
14246
10:23:55,250 --> 10:23:56,250
[Music]
14247
10:24:01,936 --> 10:24:02,936
thank you
14248
10:24:13,980 --> 10:24:14,980
Network routing and IP addressing IP
14249
10:24:17,820 --> 10:24:18,820
assigning and addressing methods
14250
10:24:20,756 --> 10:24:21,756
so having discussed both ipv4 and IPv6
14251
10:24:23,820 --> 10:24:24,820
and the difference between these
14252
10:24:25,436 --> 10:24:26,436
different types of IP addresses we now
14253
10:24:27,596 --> 10:24:28,596
want to talk specifically and in more
14254
10:24:29,700 --> 10:24:30,700
depth about how IP addresses are
14255
10:24:33,360 --> 10:24:34,360
assigned to a specific node or client or
14256
10:24:36,660 --> 10:24:37,660
server so in this module we're going to
14257
10:24:39,660 --> 10:24:40,660
look at the two different ways that IP
14258
10:24:41,756 --> 10:24:42,756
addresses are assigned this involves
14259
10:24:44,520 --> 10:24:45,520
defining the first static IP addressing
14260
10:24:47,220 --> 10:24:48,220
static meaning that the IP address is
14261
10:24:49,980 --> 10:24:50,980
always the same and dynamic IP
14262
10:24:52,800 --> 10:24:53,800
addressing which means that the IP
14263
10:24:54,720 --> 10:24:55,720
address can change we also want to talk
14264
10:24:57,360 --> 10:24:58,360
about the strengths and weaknesses of
14265
10:25:00,416 --> 10:25:01,416
each of these addressing methods and we
14266
10:25:03,000 --> 10:25:04,000
want to compare the features of one and
14267
10:25:05,460 --> 10:25:06,460
the other
14268
10:25:06,240 --> 10:25:07,240
we're also going to identify when we
14269
10:25:09,540 --> 10:25:10,540
want to use Dynamic IP addressing as
14270
10:25:12,060 --> 10:25:13,060
opposed to static IP addressing and
14271
10:25:14,936 --> 10:25:15,936
Define when we're talking about Dynamic
14272
10:25:17,096 --> 10:25:18,096
IP addressing the terms DHCP the server
14273
10:25:21,060 --> 10:25:22,060
and protocol that are responsible for
14274
10:25:23,096 --> 10:25:24,096
allowing Dynamic IP addressing to work
14275
10:25:25,500 --> 10:25:26,500
something called the scope which lets
14276
10:25:28,256 --> 10:25:29,256
the DHCP server know which IP addresses
14277
10:25:31,620 --> 10:25:32,620
are up for grabs and then the lease
14278
10:25:34,380 --> 10:25:35,380
which just like the lease on an
14279
10:25:36,240 --> 10:25:37,240
apartment
14280
10:25:37,040 --> 10:25:38,040
lets the both the server and the client
14281
10:25:40,380 --> 10:25:41,380
know when a IP address can be used and
14282
10:25:44,700 --> 10:25:45,700
for how long we also want to talk about
14283
10:25:47,040 --> 10:25:48,040
when static IP addressing would be
14284
10:25:49,256 --> 10:25:50,256
preferred and as you can probably tell
14285
10:25:51,300 --> 10:25:52,300
from the way this is worded we generally
14286
10:25:53,640 --> 10:25:54,640
want to use Dynamic IP addressing as
14287
10:25:56,460 --> 10:25:57,460
we'll talk about but there are certain
14288
10:25:57,960 --> 10:25:58,960
instances in which a static IP
14289
10:25:59,936 --> 10:26:00,936
addressing is the best method for us and
14290
10:26:03,240 --> 10:26:04,240
we'll talk about those as well
14291
10:26:05,400 --> 10:26:06,400
so first let's talk about static IP
14292
10:26:08,096 --> 10:26:09,096
addressing it's done manually and that's
14293
10:26:11,220 --> 10:26:12,220
what this really means static means
14294
10:26:13,200 --> 10:26:14,200
manual assignment which means that I
14295
10:26:16,500 --> 10:26:17,500
literally have to go to the computer and
14296
10:26:18,596 --> 10:26:19,596
type in what the IP address is and how I
14297
10:26:21,240 --> 10:26:22,240
want to use it so there are two major
14298
10:26:23,460 --> 10:26:24,460
flaws with this first it can be very
14299
10:26:26,460 --> 10:26:27,460
time consuming because it has to be done
14300
10:26:30,240 --> 10:26:31,240
manually and each address has to be
14301
10:26:32,040 --> 10:26:33,040
entered individually by hand in addition
14302
10:26:34,916 --> 10:26:35,916
this takes a lot of time and it's prone
14303
10:26:37,560 --> 10:26:38,560
to a lot of Errors
14304
10:26:39,436 --> 10:26:40,436
human error is often a factor when we're
14305
10:26:42,596 --> 10:26:43,596
configuring addresses for a large amount
14306
10:26:45,120 --> 10:26:46,120
of systems and if you can imagine I'm
14307
10:26:47,276 --> 10:26:48,276
working in a system of say 5
14308
10:26:50,756 --> 10:26:51,756
000 computers then I'm going to be
14309
10:26:52,680 --> 10:26:53,680
typing in IP addresses a lot now while
14310
10:26:55,800 --> 10:26:56,800
this may be a worthwhile method when
14311
10:26:57,660 --> 10:26:58,660
assigning a very small amount of
14312
10:26:59,096 --> 10:27:00,096
addresses it's obviously not very
14313
10:27:00,540 --> 10:27:01,540
practical when I'm talking about large
14314
10:27:01,980 --> 10:27:02,980
quantities and the other major flaw is
14315
10:27:04,916 --> 10:27:05,916
that it has to be reconfigured every
14316
10:27:07,380 --> 10:27:08,380
time the address sync scheme changes so
14317
10:27:11,040 --> 10:27:12,040
for instance if I was going from ipv4 to
14318
10:27:12,960 --> 10:27:13,960
IPv6 on my internal Network I'm going to
14319
10:27:15,540 --> 10:27:16,540
have to re-change everything once I've
14320
10:27:18,840 --> 10:27:19,840
switched over or let's say I want to
14321
10:27:20,936 --> 10:27:21,936
change my naming system maybe I want to
14322
10:27:22,740 --> 10:27:23,740
go from a Class C to a class AIP
14323
10:27:27,060 --> 10:27:28,060
addressing system if I'm an ipv4 and in
14324
10:27:29,756 --> 10:27:30,756
this case I would have to then
14325
10:27:30,720 --> 10:27:31,720
reconfigure everything on each computer
14326
10:27:32,756 --> 10:27:33,756
and you can imagine the amount of time
14327
10:27:34,256 --> 10:27:35,256
that that's going to take
14328
10:27:36,180 --> 10:27:37,180
so due to its many flaws we're really
14329
10:27:39,540 --> 10:27:40,540
not going to use this method static IP
14330
10:27:43,256 --> 10:27:44,256
addressing which means again manual
14331
10:27:45,840 --> 10:27:46,840
assignment the way you can remember that
14332
10:27:47,160 --> 10:27:48,160
is that static does not change right it
14333
10:27:51,000 --> 10:27:52,000
remains constants
14334
10:27:57,060 --> 10:27:58,060
and the word static meaning not changing
14335
10:27:59,700 --> 10:28:00,700
is what tells us that so we're only
14336
10:28:01,860 --> 10:28:02,860
going to use that in specific instances
14337
10:28:03,360 --> 10:28:04,360
and I'll talk about that a little bit
14338
10:28:04,860 --> 10:28:05,860
later
14339
10:28:05,700 --> 10:28:06,700
so as a result it's very rarely used
14340
10:28:08,400 --> 10:28:09,400
except in very specific instances I'm
14341
10:28:11,160 --> 10:28:12,160
guessing you've never had to enter the
14342
10:28:12,900 --> 10:28:13,900
IAP address on your Soho router or at
14343
10:28:16,800 --> 10:28:17,800
your computers at home and that's
14344
10:28:18,540 --> 10:28:19,540
because we're going to use this other
14345
10:28:19,860 --> 10:28:20,860
method being Dynamic addressing now as
14346
10:28:23,276 --> 10:28:24,276
the name Dynamic implies the IP address
14347
10:28:25,800 --> 10:28:26,800
can change which means that it is
14348
10:28:28,160 --> 10:28:29,160
automatically assigned now this is a lot
14349
10:28:31,680 --> 10:28:32,680
more useful of the of the two that we
14350
10:28:34,980 --> 10:28:35,980
have for many reasons it's done
14351
10:28:37,500 --> 10:28:38,500
automatically through a protocol called
14352
10:28:40,680 --> 10:28:41,680
Dynamic host configuration protocol or
14353
10:28:45,020 --> 10:28:46,020
DHCP so you ever hear DHCP that is what
14354
10:28:49,140 --> 10:28:50,140
is referred to when we're talking about
14355
10:28:50,776 --> 10:28:51,776
Dynamic IP addressing this is part of
14356
10:28:54,240 --> 10:28:55,240
the tcpip suite and it allows a central
14357
10:28:57,120 --> 10:28:58,120
system to provide IP addresses to client
14358
10:29:00,360 --> 10:29:01,360
systems now since it's done
14359
10:29:02,220 --> 10:29:03,220
automatically there's no possibility of
14360
10:29:05,040 --> 10:29:06,040
human error and it's also a lot more
14361
10:29:07,256 --> 10:29:08,256
efficient than static IP addressing as a
14362
10:29:10,320 --> 10:29:11,320
result it's a lot more common of a
14363
10:29:12,360 --> 10:29:13,360
method
14364
10:29:13,320 --> 10:29:14,320
uh it also eliminates the need to
14365
10:29:16,256 --> 10:29:17,256
reconfigure a system if the addressing
14366
10:29:19,020 --> 10:29:20,020
scheme is changed so it's far more
14367
10:29:21,900 --> 10:29:22,900
commonly used because of all these
14368
10:29:24,000 --> 10:29:25,000
reasons like we just said
14369
10:29:30,360 --> 10:29:31,360
it's more practical and more efficient
14370
10:29:32,580 --> 10:29:33,580
because I don't have to change every
14371
10:29:35,276 --> 10:29:36,276
computer
14372
10:29:42,596 --> 10:29:43,596
all I have to do is tell the DHCP
14373
10:29:45,776 --> 10:29:46,776
service computer we'll talk about that
14374
10:29:47,936 --> 10:29:48,936
in a second
14375
10:29:49,256 --> 10:29:50,256
that we're changing everything and all
14376
10:29:51,060 --> 10:29:52,060
the underling computers automatically
14377
10:29:53,160 --> 10:29:54,160
are going to change
14378
10:29:57,900 --> 10:29:58,900
so if we move over real quickly
14379
10:30:06,060 --> 10:30:07,060
into our Windows system
14380
10:30:08,820 --> 10:30:09,820
and let's go into our Network
14381
10:30:15,720 --> 10:30:16,720
properties
14382
10:30:18,960 --> 10:30:19,960
and we'll go ahead and go to change
14383
10:30:21,180 --> 10:30:22,180
adapter settings I'm going to right
14384
10:30:23,160 --> 10:30:24,160
click on this and go to properties
14385
10:30:26,520 --> 10:30:27,520
now we'll see over here if I click on
14386
10:30:29,900 --> 10:30:30,900
tcpi P4 and go to properties it says
14387
10:30:33,596 --> 10:30:34,596
obtain an IP address automatically
14388
10:30:36,240 --> 10:30:37,240
so through DHCP the IP address is being
14389
10:30:39,860 --> 10:30:40,860
automatically obtained just like DNS is
14390
10:30:42,596 --> 10:30:43,596
also going to be given out automatically
14391
10:30:44,096 --> 10:30:45,096
now if I wanted to do it statically I
14392
10:30:46,436 --> 10:30:47,436
would have to manually assign an IP
14393
10:30:48,840 --> 10:30:49,840
address a subnet mask and a default
14394
10:30:50,880 --> 10:30:51,880
gateway for each device so you can see
14395
10:30:53,700 --> 10:30:54,700
where we're not going to want to do that
14396
10:30:58,140 --> 10:30:59,140
so let's talk a little bit more about
14397
10:30:59,840 --> 10:31:00,840
DHCP or the dynamic host configuration
14398
10:31:02,756 --> 10:31:03,756
protocol
14399
10:31:03,840 --> 10:31:04,840
this is the protocol which assigns IP
14400
10:31:07,320 --> 10:31:08,320
addresses and it does this first by
14401
10:31:09,416 --> 10:31:10,416
assigning what's called or defining
14402
10:31:12,000 --> 10:31:13,000
rather What's called the scope the scope
14403
10:31:14,700 --> 10:31:15,700
or the ranges of all of the available IP
14404
10:31:17,460 --> 10:31:18,460
address on the system that's running the
14405
10:31:19,860 --> 10:31:20,860
DHCP service and what this does is it
14406
10:31:24,416 --> 10:31:25,416
takes one of the IP addresses from this
14407
10:31:26,640 --> 10:31:27,640
scope and assigns it to a computer or a
14408
10:31:29,520 --> 10:31:30,520
client so for instance let's say that
14409
10:31:32,220 --> 10:31:33,220
we're dealing for simplicity's sake with
14410
10:31:35,160 --> 10:31:36,160
a uh
14411
10:31:37,580 --> 10:31:38,580
192.168 Class C Network so the scope
14412
10:31:42,060 --> 10:31:43,060
might be something like 192.168
14413
10:31:48,140 --> 10:31:49,140
dots one
14414
10:31:50,340 --> 10:31:51,340
dot 10
14415
10:31:52,080 --> 10:31:53,080
through
14416
10:31:53,776 --> 10:31:54,776
254. this means that of the IP addresses
14417
10:31:58,200 --> 10:31:59,200
it's going to assign it's not going to
14418
10:32:00,840 --> 10:32:01,840
take anything in front of the 10. so
14419
10:32:03,960 --> 10:32:04,960
this gives us dot 1 through dot 9 to use
14420
10:32:09,060 --> 10:32:10,060
for static IP addressing so what this
14421
10:32:12,000 --> 10:32:13,000
ensures is that the DHCP server is not
14422
10:32:16,916 --> 10:32:17,916
going to assign an IP address that we
14423
10:32:19,320 --> 10:32:20,320
have already manually or statically
14424
10:32:21,416 --> 10:32:22,416
assigned to another device we'll talk
14425
10:32:23,460 --> 10:32:24,460
about why we would want to do that in a
14426
10:32:25,256 --> 10:32:26,256
minute but this ensures again that the
14427
10:32:28,916 --> 10:32:29,916
scope
14428
10:32:29,880 --> 10:32:30,880
uh that the DHCP is not going to assign
14429
10:32:34,020 --> 10:32:35,020
an IP address outside of its scope then
14430
10:32:36,840 --> 10:32:37,840
what it does it takes this available
14431
10:32:38,340 --> 10:32:39,340
address and assigned it to the client
14432
10:32:40,860 --> 10:32:41,860
for a set amount of time and this is
14433
10:32:43,800 --> 10:32:44,800
called a lease so the lease says how
14434
10:32:47,160 --> 10:32:48,160
long
14435
10:32:49,560 --> 10:32:50,560
the IP address is going to last
14436
10:32:55,080 --> 10:32:56,080
now the reason that we had leases is
14437
10:32:57,900 --> 10:32:58,900
because remember if I turn off my
14438
10:32:59,580 --> 10:33:00,580
computer it no longer needs an IP
14439
10:33:01,436 --> 10:33:02,436
address it also means that let's say I'm
14440
10:33:04,680 --> 10:33:05,680
taking a computer away I don't if I have
14441
10:33:07,980 --> 10:33:08,980
a if it has a lease of forever then that
14442
10:33:11,220 --> 10:33:12,220
computer now has one of my available IP
14443
10:33:13,380 --> 10:33:14,380
addresses so sometimes we'll have an IP
14444
10:33:15,960 --> 10:33:16,960
address with a 24-hour lease or maybe a
14445
10:33:19,256 --> 10:33:20,256
two day lease but whatever that lease is
14446
10:33:21,776 --> 10:33:22,776
at the end of that lease it's going to
14447
10:33:23,460 --> 10:33:24,460
have to re-again ask for another IP
14448
10:33:26,820 --> 10:33:27,820
address this is also the way that we can
14449
10:33:28,980 --> 10:33:29,980
share a limited number of IP addresses
14450
10:33:34,096 --> 10:33:35,096
with a lot of uh computers or nodes
14451
10:33:40,436 --> 10:33:41,436
so when we had the internet we used to
14452
10:33:42,360 --> 10:33:43,360
dial up to the to our ISP or Internet
14453
10:33:45,480 --> 10:33:46,480
service provider what this would allow
14454
10:33:48,180 --> 10:33:49,180
is it allowed our
14455
10:33:50,520 --> 10:33:51,520
uh ISP to provide us with one IP address
14456
10:33:53,936 --> 10:33:54,936
that only lasted for a certain amount of
14457
10:33:55,620 --> 10:33:56,620
time and then when we disconnected the
14458
10:33:58,436 --> 10:33:59,436
IP address or disconnected from the
14459
10:34:00,596 --> 10:34:01,596
server and therefore didn't need the IP
14460
10:34:02,040 --> 10:34:03,040
address it could assign it to someone
14461
10:34:03,180 --> 10:34:04,180
else and it didn't have to worry about
14462
10:34:04,916 --> 10:34:05,916
us coming back on and wanting to use the
14463
10:34:06,720 --> 10:34:07,720
same IP address because remember one of
14464
10:34:08,880 --> 10:34:09,880
the rules is you cannot
14465
10:34:13,680 --> 10:34:14,680
have
14466
10:34:15,596 --> 10:34:16,596
two devices
14467
10:34:20,160 --> 10:34:21,160
with one IP address
14468
10:34:24,480 --> 10:34:25,480
all right now let's talk about how this
14469
10:34:27,660 --> 10:34:28,660
works from the client's point of view
14470
10:34:29,936 --> 10:34:30,936
basically what happens is I have a DHCP
14471
10:34:33,240 --> 10:34:34,240
server here and it has what's called a
14472
10:34:36,480 --> 10:34:37,480
trusted connection to the switch
14473
10:34:39,596 --> 10:34:40,596
we'll defined what a switch is
14474
10:34:40,980 --> 10:34:41,980
previously and we'll talk a bit more
14475
10:34:42,540 --> 10:34:43,540
about them later as well but it has a
14476
10:34:45,480 --> 10:34:46,480
trusted connection this computer say
14477
10:34:47,700 --> 10:34:48,700
comes online
14478
10:34:50,340 --> 10:34:51,340
and says hi
14479
10:34:53,700 --> 10:34:54,700
can I join your network
14480
10:34:55,680 --> 10:34:56,680
can I get an IP address it sends its
14481
10:34:59,340 --> 10:35:00,340
request through what's called an
14482
10:35:01,916 --> 10:35:02,916
untrusted connection
14483
10:35:03,540 --> 10:35:04,540
to wherever the DHCP server is now the
14484
10:35:06,660 --> 10:35:07,660
DHCP server at some point finds this
14485
10:35:09,300 --> 10:35:10,300
because this is generally a broadcast
14486
10:35:12,960 --> 10:35:13,960
because again it's not a unicast it's a
14487
10:35:15,720 --> 10:35:16,720
broadcast because this computer coming
14488
10:35:17,220 --> 10:35:18,220
on doesn't know where the DHCP server is
14489
10:35:20,520 --> 10:35:21,520
so it sends a broadcast message out the
14490
10:35:23,160 --> 10:35:24,160
DHC per P server then responds and
14491
10:35:26,400 --> 10:35:27,400
offers a lease on an IP address at which
14492
10:35:29,400 --> 10:35:30,400
point this untrusted or unassigned
14493
10:35:31,500 --> 10:35:32,500
connection becomes a trusted one now
14494
10:35:34,860 --> 10:35:35,860
when the lease goes out it's again
14495
10:35:36,240 --> 10:35:37,240
untrusted and so it needs to repeat the
14496
10:35:38,460 --> 10:35:39,460
entire process again
14497
10:35:40,320 --> 10:35:41,320
now so far we've been pretty fair to
14498
10:35:43,380 --> 10:35:44,380
DHCP and expanded on the benefits for
14499
10:35:46,500 --> 10:35:47,500
dynamic addressing but there are some
14500
10:35:49,140 --> 10:35:50,140
exceptions when a network is configured
14501
10:35:51,380 --> 10:35:52,380
uh for DHCP and we don't want every
14502
10:35:55,680 --> 10:35:56,680
single device to be automatically
14503
10:35:58,320 --> 10:35:59,320
assigned an IP address
14504
10:36:00,240 --> 10:36:01,240
for instance
14505
10:36:02,040 --> 10:36:03,040
um
14506
10:36:03,240 --> 10:36:04,240
the DHCP server itself needs to have a
14507
10:36:07,560 --> 10:36:08,560
static IP address this is because we
14508
10:36:10,916 --> 10:36:11,916
don't want the DHCP server to be
14509
10:36:14,820 --> 10:36:15,820
changing addresses and what's going to
14510
10:36:16,740 --> 10:36:17,740
happen is if we have a lease
14511
10:36:17,936 --> 10:36:18,936
theoretically the DHCP server could
14512
10:36:20,640 --> 10:36:21,640
change its IP address and since every
14513
10:36:23,820 --> 10:36:24,820
computer on the network needs to know
14514
10:36:25,436 --> 10:36:26,436
where to go that's going to have to
14515
10:36:27,180 --> 10:36:28,180
remain the same this is going to go the
14516
10:36:28,860 --> 10:36:29,860
same with the domain name server so the
14517
10:36:30,960 --> 10:36:31,960
DNS server which allows us to convert
14518
10:36:33,596 --> 10:36:34,596
between say google.com
14519
10:36:37,200 --> 10:36:38,200
and the IP address so we don't want to
14520
10:36:41,460 --> 10:36:42,460
have to find this every single time and
14521
10:36:43,916 --> 10:36:44,916
we have to set it as something specific
14522
10:36:45,900 --> 10:36:46,900
meaning static we're also going to put
14523
10:36:48,180 --> 10:36:49,180
our web server as some static IP address
14524
10:36:51,360 --> 10:36:52,360
this is the reason why if you wanted to
14525
10:36:54,080 --> 10:36:55,080
get an account with your ISP or internet
14526
10:36:56,936 --> 10:36:57,936
service provider and you wanted to run
14527
10:36:59,700 --> 10:37:00,700
and web server from your computer at
14528
10:37:03,000 --> 10:37:04,000
home you would need to ask for a static
14529
10:37:05,640 --> 10:37:06,640
IP address be because
14530
10:37:08,756 --> 10:37:09,756
that's the only way that someone can
14531
10:37:10,916 --> 10:37:11,916
link through DNS
14532
10:37:13,020 --> 10:37:14,020
to your web server and so our web
14533
10:37:15,120 --> 10:37:16,120
servers always has to be static because
14534
10:37:16,800 --> 10:37:17,800
when I type in google.com I always
14535
10:37:18,480 --> 10:37:19,480
wanted to go to one of a few different
14536
10:37:20,220 --> 10:37:21,220
IP addresses
14537
10:37:21,900 --> 10:37:22,900
finally printers are something else that
14538
10:37:24,060 --> 10:37:25,060
we want to have
14539
10:37:27,240 --> 10:37:28,240
the printer we don't want to move around
14540
10:37:28,680 --> 10:37:29,680
we want to be able to lock it in when we
14541
10:37:31,500 --> 10:37:32,500
install it on the computer same with any
14542
10:37:34,380 --> 10:37:35,380
servers also routers the Gateway
14543
10:37:37,680 --> 10:37:38,680
computer or the Gateway device that
14544
10:37:40,080 --> 10:37:41,080
allows us to get out to the network we
14545
10:37:41,700 --> 10:37:42,700
need that to remain the same so that's
14546
10:37:43,500 --> 10:37:44,500
why when we Define the scope and in
14547
10:37:45,900 --> 10:37:46,900
previous example we defined it as any IP
14548
10:37:48,300 --> 10:37:49,300
address between 10 and 254. we don't
14549
10:37:50,700 --> 10:37:51,700
want it to change
14550
10:37:52,740 --> 10:37:53,740
because we want these nine IP addresses
14551
10:37:55,740 --> 10:37:56,740
to be ones that we can assign now
14552
10:37:57,360 --> 10:37:58,360
sometimes we're going to make this a
14553
10:37:58,320 --> 10:37:59,320
little larger so that way
14554
10:38:00,480 --> 10:38:01,480
we can assign a lot more static IP
14555
10:38:03,240 --> 10:38:04,240
addresses so also maybe a wireless
14556
10:38:06,120 --> 10:38:07,120
access point we might want to be static
14557
10:38:08,580 --> 10:38:09,580
etc etc and all of this again is done
14558
10:38:10,980 --> 10:38:11,980
through a web interface or through
14559
10:38:14,360 --> 10:38:15,360
some sort of
14560
10:38:16,680 --> 10:38:17,680
router
14561
10:38:18,416 --> 10:38:19,416
device or through a terminal or
14562
10:38:20,880 --> 10:38:21,880
something so this is not something we're
14563
10:38:22,620 --> 10:38:23,620
physically hard wiring onto the device
14564
10:38:24,360 --> 10:38:25,360
because again that's that's a MAC
14565
10:38:25,860 --> 10:38:26,860
address a physical address but this is
14566
10:38:28,256 --> 10:38:29,256
something that we want to set through a
14567
10:38:30,720 --> 10:38:31,720
software of some sort
14568
10:38:33,660 --> 10:38:34,660
all right so just to recap what we
14569
10:38:35,276 --> 10:38:36,276
talked about we defined static IP
14570
10:38:37,980 --> 10:38:38,980
addressing again static means that the
14571
10:38:40,800 --> 10:38:41,800
IP address does not change
14572
10:38:44,756 --> 10:38:45,756
it also means that it had to have been
14573
10:38:47,480 --> 10:38:48,480
manually assigned
14574
10:38:50,096 --> 10:38:51,096
okay
14575
10:38:52,256 --> 10:38:53,256
now we also talked about Dynamic IP
14576
10:38:54,480 --> 10:38:55,480
addressing
14577
10:38:55,680 --> 10:38:56,680
which DHCP allows us to do and this
14578
10:38:59,460 --> 10:39:00,460
means that the IP address can change
14579
10:39:01,820 --> 10:39:02,820
because it is automatically assigned
14580
10:39:05,756 --> 10:39:06,756
one thing I didn't specifically talk
14581
10:39:07,800 --> 10:39:08,800
about what we referenced in previous
14582
10:39:09,360 --> 10:39:10,360
modules too is that a pipa address
14583
10:39:13,380 --> 10:39:14,380
that automatically assigned IP address
14584
10:39:16,580 --> 10:39:17,580
which if the dynamic IP address system
14585
10:39:19,740 --> 10:39:20,740
is not working so the DHCP server for
14586
10:39:21,960 --> 10:39:22,960
instance is down and it can't get an IP
14587
10:39:24,776 --> 10:39:25,776
address from the DHCP server it's going
14588
10:39:27,180 --> 10:39:28,180
to assign itself its own IP address if
14589
10:39:29,936 --> 10:39:30,936
you remember that was 169 about 254 dot
14590
10:39:34,320 --> 10:39:35,320
x dot X so if you see this is your IP
14591
10:39:37,320 --> 10:39:38,320
address then guess what your DHCP server
14592
10:39:40,680 --> 10:39:41,680
is down
14593
10:39:42,240 --> 10:39:43,240
we also identify the strengths and
14594
10:39:43,800 --> 10:39:44,800
weaknesses of each of these so um
14595
10:39:47,276 --> 10:39:48,276
we Define the static we Define dynamic
14596
10:39:49,320 --> 10:39:50,320
and then we identify the strengths and
14597
10:39:50,756 --> 10:39:51,756
weaknesses of each remember the strength
14598
10:39:53,276 --> 10:39:54,276
of dynamic is that
14599
10:39:56,820 --> 10:39:57,820
it's easy
14600
10:39:58,980 --> 10:39:59,980
and it requires less work if we change
14601
10:40:01,620 --> 10:40:02,620
anything
14602
10:40:03,300 --> 10:40:04,300
of course the Dynamics or the the
14603
10:40:05,340 --> 10:40:06,340
downside of it
14604
10:40:06,960 --> 10:40:07,960
could be this apipa or we don't want
14605
10:40:11,220 --> 10:40:12,220
um the IP address to change
14606
10:40:13,680 --> 10:40:14,680
we also talked about when to use Dynamic
14607
10:40:16,320 --> 10:40:17,320
IP addressing which is in most cases we
14608
10:40:19,500 --> 10:40:20,500
Define DHCP which allows a dynamic IP
14609
10:40:23,160 --> 10:40:24,160
addressing to work
14610
10:40:24,360 --> 10:40:25,360
scope which is basically the range of IP
14611
10:40:27,480 --> 10:40:28,480
addresses
14612
10:40:30,960 --> 10:40:31,960
and the lease
14613
10:40:33,840 --> 10:40:34,840
which is how long the IP address is
14614
10:40:36,060 --> 10:40:37,060
going to be
14615
10:40:37,380 --> 10:40:38,380
sent out for and then we recognize when
14616
10:40:39,720 --> 10:40:40,720
static IP addressing is preferred for
14617
10:40:42,000 --> 10:40:43,000
instance when we're dealing with
14618
10:40:43,256 --> 10:40:44,256
printers
14619
10:40:44,820 --> 10:40:45,820
or routers
14620
10:40:46,860 --> 10:40:47,860
or even the DHCP server itself
14621
10:40:51,240 --> 10:40:52,240
which we cannot have change
14622
10:40:57,040 --> 10:40:58,040
[Music]
14623
10:41:13,700 --> 10:41:14,700
welcome to module 6 lessons lesson 6 DNS
14624
10:41:17,936 --> 10:41:18,936
the name naming system
14625
10:41:21,900 --> 10:41:22,900
covered up we're going to cover a lot of
14626
10:41:23,820 --> 10:41:24,820
stuff in this presentation but I'll try
14627
10:41:25,916 --> 10:41:26,916
and get through as quickly as I can
14628
10:41:27,900 --> 10:41:28,900
what uh we need to know what DNS is what
14629
10:41:30,120 --> 10:41:31,120
our domains the fully qualified domain
14630
10:41:32,700 --> 10:41:33,700
name
14631
10:41:33,596 --> 10:41:34,596
the DNS root servers so what happens or
14632
10:41:36,180 --> 10:41:37,180
how does the system actually how do we
14633
10:41:38,820 --> 10:41:39,820
interrogate it and how does it update
14634
10:41:40,500 --> 10:41:41,500
itself
14635
10:41:41,700 --> 10:41:42,700
what are DNS records as well this is
14636
10:41:43,740 --> 10:41:44,740
stuff that's actually in the syllabus
14637
10:41:45,840 --> 10:41:46,840
now I'm sure you've already heard of
14638
10:41:47,820 --> 10:41:48,820
domain name system or DNS you can see in
14639
10:41:51,060 --> 10:41:52,060
the um output here the image we've
14640
10:41:53,756 --> 10:41:54,756
got.com dot org.us there's actually
14641
10:41:57,120 --> 10:41:58,120
loads and they're added um quite rapidly
14642
10:41:59,720 --> 10:42:00,720
and as each country has
14643
10:42:02,936 --> 10:42:03,936
um appealed for their own top level
14644
10:42:05,756 --> 10:42:06,756
domain more and more have been added so
14645
10:42:07,320 --> 10:42:08,320
there's lots of countries now that you
14646
10:42:09,596 --> 10:42:10,596
can register domain names for some of
14647
10:42:11,936 --> 10:42:12,936
them are protected for example
14648
10:42:14,220 --> 10:42:15,220
um if we go to.com
14649
10:42:18,720 --> 10:42:19,720
dot a u for Australia you actually have
14650
10:42:22,560 --> 10:42:23,560
to have a business uh number so
14651
10:42:26,756 --> 10:42:27,756
even if you live in Australia you must
14652
10:42:29,520 --> 10:42:30,520
have um it's called an ABN Australian
14653
10:42:32,220 --> 10:42:33,220
business number so not you can't just
14654
10:42:35,700 --> 10:42:36,700
have anyone having a DOT com.eu other
14655
10:42:38,756 --> 10:42:39,756
countries have got restrictions some
14656
10:42:40,380 --> 10:42:41,380
haven't so it just depends on where you
14657
10:42:43,380 --> 10:42:44,380
are so it's the name of a computer it's
14658
10:42:46,680 --> 10:42:47,680
got a an IP address on the internet now
14659
10:42:49,560 --> 10:42:50,560
these can actually be shared you can
14660
10:42:51,000 --> 10:42:52,000
have some of the same domain names if
14661
10:42:52,620 --> 10:42:53,620
you buy cheap hosting and they'll all be
14662
10:42:55,200 --> 10:42:56,200
sitting on the same IP address but this
14663
10:42:58,380 --> 10:42:59,380
DNS can deal with this
14664
10:43:00,776 --> 10:43:01,776
so yep that's just what I've said
14665
10:43:03,120 --> 10:43:04,120
if you uh
14666
10:43:05,040 --> 10:43:06,040
for example I used to host of these but
14667
10:43:07,800 --> 10:43:08,800
not anymore
14668
10:43:08,960 --> 10:43:09,960
uh
14669
10:43:10,620 --> 10:43:11,620
what was it called HostGator
14670
10:43:16,800 --> 10:43:17,800
I'm not recommending these by the way
14671
10:43:19,436 --> 10:43:20,436
you could have this guy's website
14672
10:43:21,480 --> 10:43:22,480
somebody else's another person another
14673
10:43:23,880 --> 10:43:24,880
person but they're all sharing
14674
10:43:30,776 --> 10:43:31,776
the same IP address but that's easily
14675
10:43:33,416 --> 10:43:34,416
taken care of
14676
10:43:34,980 --> 10:43:35,980
so what is it it resolves the names
14677
10:43:37,140 --> 10:43:38,140
associated with a server to its IP
14678
10:43:39,480 --> 10:43:40,480
address
14679
10:43:41,756 --> 10:43:42,756
so you can see on my home computer here
14680
10:43:45,416 --> 10:43:46,416
I issued a ping cisco.com well this
14681
10:43:51,000 --> 10:43:52,000
a URL is sitting on a server somewhere
14682
10:43:54,540 --> 10:43:55,540
and probably on spread among quite a few
14683
10:43:57,240 --> 10:43:58,240
servers actually but somewhere from my
14684
10:44:01,620 --> 10:44:02,620
home
14685
10:44:02,520 --> 10:44:03,520
wherever I am I've got to get through to
14686
10:44:05,400 --> 10:44:06,400
my
14687
10:44:06,380 --> 10:44:07,380
ISP and then obviously we've got a whole
14688
10:44:09,776 --> 10:44:10,776
bunch of other hosting companies
14689
10:44:11,240 --> 10:44:12,240
wherever they may be and then finally we
14690
10:44:14,700 --> 10:44:15,700
get to the building
14691
10:44:16,916 --> 10:44:17,916
hmm
14692
10:44:19,380 --> 10:44:20,380
that Cisco owned maybe Paulo Alto or
14693
10:44:23,160 --> 10:44:24,160
somewhere else but there has to be a
14694
10:44:24,776 --> 10:44:25,776
result between this and what actually
14695
10:44:27,120 --> 10:44:28,120
comes back because tcpip doesn't ping
14696
10:44:30,960 --> 10:44:31,960
names it pings uh IP addresses so 172
14697
10:44:35,640 --> 10:44:36,640
163 4.161 that could have changed but
14698
10:44:39,000 --> 10:44:40,000
something has to happen before the icmp
14699
10:44:43,200 --> 10:44:44,200
packet can be built and as you know from
14700
10:44:46,200 --> 10:44:47,200
other lectures he's got to have uh
14701
10:44:48,416 --> 10:44:49,416
inside their Source destination and
14702
10:44:52,020 --> 10:44:53,020
their data whatever else inside the
14703
10:44:54,720 --> 10:44:55,720
packet so DNS will take care of the uh
14704
10:44:58,436 --> 10:44:59,436
resolve for us
14705
10:45:01,560 --> 10:45:02,560
when we tried to access a
14706
10:45:03,060 --> 10:45:04,060
samplecompany.com from the web browser
14707
10:45:04,916 --> 10:45:05,916
DNS translates the domain name into an
14708
10:45:08,096 --> 10:45:09,096
IP address
14709
10:45:11,340 --> 10:45:12,340
so I've just put an IP address if you're
14710
10:45:13,860 --> 10:45:14,860
super super smart and got a great memory
14711
10:45:15,840 --> 10:45:16,840
you could basically browse the entire
14712
10:45:17,756 --> 10:45:18,756
internet just using IP addresses however
14713
10:45:21,360 --> 10:45:22,360
if it's something new for example if you
14714
10:45:23,820 --> 10:45:24,820
want to go to
14715
10:45:25,520 --> 10:45:26,520
xyzsite.com you're not going to know
14716
10:45:28,020 --> 10:45:29,020
obviously the IP address and this can
14717
10:45:29,880 --> 10:45:30,880
change over time by the way they can
14718
10:45:32,040 --> 10:45:33,040
move to another company and assimilate
14719
10:45:33,960 --> 10:45:34,960
with someone else or buy them out
14720
10:45:39,180 --> 10:45:40,180
so that IP address is used by our
14721
10:45:41,096 --> 10:45:42,096
computer to communicate with the
14722
10:45:42,660 --> 10:45:43,660
corresponding server on the network
14723
10:45:46,620 --> 10:45:47,620
as a database DLS knows about the
14724
10:45:48,840 --> 10:45:49,840
relationship between the domain name and
14725
10:45:51,060 --> 10:45:52,060
its IP address it's a distributed
14726
10:45:53,700 --> 10:45:54,700
databases spread across the world I'll
14727
10:45:56,276 --> 10:45:57,276
come up to this morning here but um
14728
10:45:58,680 --> 10:45:59,680
you've got your ISP which will probably
14729
10:46:01,256 --> 10:46:02,256
have several thousand of the most common
14730
10:46:04,096 --> 10:46:05,096
DNS addresses
14731
10:46:07,080 --> 10:46:08,080
and and mappings in there if there isn't
14732
10:46:09,900 --> 10:46:10,900
one there then when you do your search
14733
10:46:12,080 --> 10:46:13,080
at home
14734
10:46:13,860 --> 10:46:14,860
if it's not there then quite quickly it
14735
10:46:15,720 --> 10:46:16,720
will be forwarded to
14736
10:46:17,756 --> 10:46:18,756
like possibly it might not be the um one
14737
10:46:21,060 --> 10:46:22,060
of the root servers which I'll come to
14738
10:46:22,436 --> 10:46:23,436
but it might be an authoritative DNS
14739
10:46:25,860 --> 10:46:26,860
server that will hopefully resolve if
14740
10:46:28,980 --> 10:46:29,980
not then it can carry on
14741
10:46:32,460 --> 10:46:33,460
it uses UDP Port 53 just uh bear that in
14742
10:46:36,180 --> 10:46:37,180
mind because you could come up in the
14743
10:46:38,040 --> 10:46:39,040
exam
14744
10:46:39,080 --> 10:46:40,080
uh just people argue that it DNS doesn't
14745
10:46:43,860 --> 10:46:44,860
use
14746
10:46:44,880 --> 10:46:45,880
UDP it does for our for our purposes DNS
14747
10:46:48,840 --> 10:46:49,840
uses UDP now if you happen to be working
14748
10:46:51,416 --> 10:46:52,416
for an internet service provider then um
14749
10:46:55,380 --> 10:46:56,380
TCP is used but it's used for Zone
14750
10:46:58,320 --> 10:46:59,320
transfer so all the domain names that um
14751
10:47:02,220 --> 10:47:03,220
will be transferred across that
14752
10:47:03,660 --> 10:47:04,660
obviously has to be done reliably or
14753
10:47:05,880 --> 10:47:06,880
large requests
14754
10:47:07,500 --> 10:47:08,500
it can also be used if there's multiple
14755
10:47:12,900 --> 10:47:13,900
this depends how you've got it all set
14756
10:47:14,640 --> 10:47:15,640
up if there's multiple failures looking
14757
10:47:16,436 --> 10:47:17,436
for
14758
10:47:18,140 --> 10:47:19,140
xyz.com then it could also move to TCP
14759
10:47:23,040 --> 10:47:24,040
this is because it could be caused by a
14760
10:47:25,680 --> 10:47:26,680
UDP dropouts or fragmentation
14761
10:47:28,560 --> 10:47:29,560
but we probably wouldn't need to worry
14762
10:47:30,240 --> 10:47:31,240
about that for our day-to-day jobs
14763
10:47:33,776 --> 10:47:34,776
our DNS database or the DNS database
14764
10:47:37,020 --> 10:47:38,020
divided into sections called zones these
14765
10:47:39,240 --> 10:47:40,240
store name information about one or more
14766
10:47:40,980 --> 10:47:41,980
domains
14767
10:47:44,460 --> 10:47:45,460
and the domain is included in the zone
14768
10:47:46,436 --> 10:47:47,436
The Zone becomes an authoritative source
14769
10:47:48,480 --> 10:47:49,480
of information about that domain
14770
10:47:52,860 --> 10:47:53,860
so as I've already said we need our
14771
10:47:55,436 --> 10:47:56,436
routers and multiles which is we we
14772
10:47:58,320 --> 10:47:59,320
concerned about IP addresses to make
14773
10:48:00,060 --> 10:48:01,060
forwarding decisions so we had to have
14774
10:48:02,096 --> 10:48:03,096
this service created
14775
10:48:07,560 --> 10:48:08,560
uh you we know this stuff already
14776
10:48:09,300 --> 10:48:10,300
difficult to remember kind of alluded to
14777
10:48:11,640 --> 10:48:12,640
it
14778
10:48:15,000 --> 10:48:16,000
so the IP address with the domain system
14779
10:48:17,700 --> 10:48:18,700
we don't need to go through the headache
14780
10:48:19,800 --> 10:48:20,800
of remembering the IP addresses
14781
10:48:23,160 --> 10:48:24,160
a little flogging the flogging the point
14782
10:48:25,020 --> 10:48:26,020
a bit here
14783
10:48:26,520 --> 10:48:27,520
so the DNS name system is based upon the
14784
10:48:29,756 --> 10:48:30,756
domain name space
14785
10:48:31,860 --> 10:48:32,860
collection of unique names that denote
14786
10:48:33,540 --> 10:48:34,540
other kinds of information such as the
14787
10:48:35,400 --> 10:48:36,400
IP address now there has to be certain
14788
10:48:37,620 --> 10:48:38,620
rules in place obviously and these rules
14789
10:48:39,900 --> 10:48:40,900
have been added to and amended if you if
14790
10:48:42,776 --> 10:48:43,776
you've got the time and the inclination
14791
10:48:44,700 --> 10:48:45,700
to read through the rfcs and certainly
14792
10:48:47,096 --> 10:48:48,096
when we come to see Name Records
14793
10:48:49,916 --> 10:48:50,916
conical names I'm not saying that twice
14794
10:48:54,060 --> 10:48:55,060
they had to issue an update on the RFC
14795
10:48:57,840 --> 10:48:58,840
because people were getting a bit
14796
10:48:59,400 --> 10:49:00,400
confused about what it what it did and
14797
10:49:01,860 --> 10:49:02,860
this is one of the things about when you
14798
10:49:03,300 --> 10:49:04,300
when you create something and you write
14799
10:49:05,400 --> 10:49:06,400
the rules
14800
10:49:06,900 --> 10:49:07,900
of the documentation you
14801
10:49:09,360 --> 10:49:10,360
you presume people already understand
14802
10:49:11,040 --> 10:49:12,040
stuff because it's in your head this is
14803
10:49:13,080 --> 10:49:14,080
why it's handy to get other people to
14804
10:49:14,880 --> 10:49:15,880
write the documentation and then you
14805
10:49:16,320 --> 10:49:17,320
read it
14806
10:49:17,700 --> 10:49:18,700
and I'm saying that because
14807
10:49:18,960 --> 10:49:19,960
documentation is included in the network
14808
10:49:21,120 --> 10:49:22,120
plus the exam
14809
10:49:22,620 --> 10:49:23,620
so the namespace is a hierarchically
14810
10:49:25,320 --> 10:49:26,320
there's too many long words today
14811
10:49:27,620 --> 10:49:28,620
structured and has rules to uh that let
14812
10:49:30,596 --> 10:49:31,596
the namespace be divided into subsets
14813
10:49:34,320 --> 10:49:35,320
so in the land uh the domain is a sub
14814
10:49:36,720 --> 10:49:37,720
Network consisting of a group of clients
14815
10:49:38,460 --> 10:49:39,460
and servers I'm not talking about the um
14816
10:49:41,160 --> 10:49:42,160
your internal
14817
10:49:42,540 --> 10:49:43,540
um intranet for example
14818
10:49:46,140 --> 10:49:47,140
I'm just talking about the day-to-day
14819
10:49:47,820 --> 10:49:48,820
lands of IP addresses you could have the
14820
10:49:50,040 --> 10:49:51,040
intranet or obviously
14821
10:49:52,140 --> 10:49:53,140
um Microsoft also has a naming system
14822
10:49:55,080 --> 10:49:56,080
the active directory so we're not
14823
10:49:57,660 --> 10:49:58,660
talking about that
14824
10:50:01,020 --> 10:50:02,020
so Internet domain is a descriptor of
14825
10:50:03,360 --> 10:50:04,360
The Logical grouping of names and it
14826
10:50:06,360 --> 10:50:07,360
indicates whether the names belong to
14827
10:50:08,340 --> 10:50:09,340
the following commercial entities and
14828
10:50:11,540 --> 10:50:12,540
non-non-profits I'm not sure what the
14829
10:50:13,380 --> 10:50:14,380
non-profit is.org isn't it
14830
10:50:16,200 --> 10:50:17,200
which isn't isn't really the case
14831
10:50:18,300 --> 10:50:19,300
because
14832
10:50:19,620 --> 10:50:20,620
um I've got a DOT org website so it's
14833
10:50:21,720 --> 10:50:22,720
not protected you don't have to be a
14834
10:50:23,220 --> 10:50:24,220
registered uh charity
14835
10:50:26,400 --> 10:50:27,400
educational is dot uh Ed I don't think
14836
10:50:30,416 --> 10:50:31,416
it's dot EU it's dot e d u now I you
14837
10:50:34,680 --> 10:50:35,680
can't get these as far as I know
14838
10:50:36,120 --> 10:50:37,120
certainly not for USA you have to be um
14839
10:50:38,936 --> 10:50:39,936
a uni
14840
10:50:41,460 --> 10:50:42,460
College something like that so I presume
14841
10:50:44,276 --> 10:50:45,276
you have to have some sort of
14842
10:50:45,060 --> 10:50:46,060
documentation or number
14843
10:50:47,880 --> 10:50:48,880
government agencies.gov
14844
10:50:51,240 --> 10:50:52,240
and so on
14845
10:50:53,880 --> 10:50:54,880
you can subdivide the domain into groups
14846
10:50:56,220 --> 10:50:57,220
called subdomain
14847
10:50:58,380 --> 10:50:59,380
so the DNS domain can also contain hosts
14848
10:51:01,916 --> 10:51:02,916
these refer to computers and services so
14849
10:51:05,460 --> 10:51:06,460
we've got an example here
14850
10:51:06,360 --> 10:51:07,360
training.samplecompany.com
14851
10:51:11,040 --> 10:51:12,040
so this is the first obviously the top
14852
10:51:14,580 --> 10:51:15,580
top level domain which we talk about
14853
10:51:16,560 --> 10:51:17,560
then somebody's registered this
14854
10:51:20,460 --> 10:51:21,460
but then when you go into your
14855
10:51:22,860 --> 10:51:23,860
admin panel
14856
10:51:25,560 --> 10:51:26,560
you can add these sub domains here for
14857
10:51:29,040 --> 10:51:30,040
example my
14858
10:51:32,276 --> 10:51:33,276
I think it's called rack start
14859
10:51:35,340 --> 10:51:36,340
how to
14860
10:51:40,500 --> 10:51:41,500
network.com I've got the same sort of
14861
10:51:42,660 --> 10:51:43,660
thing I created this subdomain which has
14862
10:51:46,500 --> 10:51:47,500
got its own IP address at
14863
10:51:49,256 --> 10:51:50,256
howtonnetwork.com is sitting somewhere
14864
10:51:52,680 --> 10:51:53,680
um
14865
10:51:53,340 --> 10:51:54,340
actually know where it is it's sitting
14866
10:51:55,500 --> 10:51:56,500
on a server say say no
14867
10:51:59,096 --> 10:52:00,096
I IO the the um racks are sitting
14868
10:52:03,120 --> 10:52:04,120
somewhere else because I've used DNS
14869
10:52:05,340 --> 10:52:06,340
records that sit in in um oh
14870
10:52:10,380 --> 10:52:11,380
I actually remember where it is
14871
10:52:13,380 --> 10:52:14,380
up at Nevada just so you get the point
14872
10:52:15,480 --> 10:52:16,480
anyway
14873
10:52:18,360 --> 10:52:19,360
so samplecomedy.com the.com is known as
14874
10:52:21,900 --> 10:52:22,900
the TLD top level domain
14875
10:52:24,540 --> 10:52:25,540
okay so you could be asked this in the
14876
10:52:26,340 --> 10:52:27,340
exam this is ISA the fqdn the fully
14877
10:52:29,400 --> 10:52:30,400
qualified domain name is a complete
14878
10:52:31,320 --> 10:52:32,320
domain name for a specific computer or
14879
10:52:33,360 --> 10:52:34,360
host so it's got the host name and the
14880
10:52:36,480 --> 10:52:37,480
domain name
14881
10:52:38,096 --> 10:52:39,096
so for the fqdn for a hypothetical main
14882
10:52:42,300 --> 10:52:43,300
mail server might be mail one and you
14883
10:52:45,840 --> 10:52:46,840
probably have this if you're in a
14884
10:52:47,040 --> 10:52:48,040
reasonably sized company that's got a
14885
10:52:48,480 --> 10:52:49,480
dedicated Mouse server so you're
14886
10:52:50,040 --> 10:52:51,040
handling all your mail
14887
10:52:52,140 --> 10:52:53,140
most of these services are named you
14888
10:52:55,980 --> 10:52:56,980
know mail one mail two whatever and then
14889
10:52:58,980 --> 10:52:59,980
your company name so you're managing all
14890
10:53:01,436 --> 10:53:02,436
of your
14891
10:53:02,700 --> 10:53:03,700
um incoming and outgoing mail which is
14892
10:53:04,916 --> 10:53:05,916
probably
14893
10:53:06,060 --> 10:53:07,060
um a good idea
14894
10:53:07,860 --> 10:53:08,860
so you can Blacklist and and comply with
14895
10:53:11,040 --> 10:53:12,040
other legal requirements
14896
10:53:14,640 --> 10:53:15,640
so mail one is a host obviously you can
14897
10:53:18,060 --> 10:53:19,060
use more than one server you can use
14898
10:53:20,640 --> 10:53:21,640
virtualization whatever you want but um
14899
10:53:23,960 --> 10:53:24,960
hypothetically speaking it's a a server
14900
10:53:27,380 --> 10:53:28,380
dot com is the TRD as we mentioned
14901
10:53:32,160 --> 10:53:33,160
so DNS root servers these are the
14902
10:53:35,276 --> 10:53:36,276
contain the top level domain registry
14903
10:53:37,740 --> 10:53:38,740
that maintain the global domains so at
14904
10:53:40,740 --> 10:53:41,740
some point if you register a brand new
14905
10:53:43,436 --> 10:53:44,436
domain name
14906
10:53:44,880 --> 10:53:45,880
you'd register it with your
14907
10:53:46,860 --> 10:53:47,860
um
14908
10:53:48,480 --> 10:53:49,480
it could be with your hosting company
14909
10:53:50,936 --> 10:53:51,936
I'll just put HC and then that
14910
10:53:53,400 --> 10:53:54,400
eventually will get forwarded to the um
14911
10:53:57,840 --> 10:53:58,840
the TLD and then that will be forwarded
14912
10:54:00,860 --> 10:54:01,860
to non-root service So eventually your
14913
10:54:05,460 --> 10:54:06,460
ISP will probably
14914
10:54:08,276 --> 10:54:09,276
get a copy
14915
10:54:11,880 --> 10:54:12,880
so as of first of August 2018 root
14916
10:54:16,020 --> 10:54:17,020
server consists of 933 instances these
14917
10:54:19,800 --> 10:54:20,800
are operated by 12 independent route
14918
10:54:21,480 --> 10:54:22,480
servers if you're interested in more
14919
10:54:23,040 --> 10:54:24,040
information you can go to root
14920
10:54:25,040 --> 10:54:26,040
service.org and have a read up and
14921
10:54:27,240 --> 10:54:28,240
they've got some maps on there of where
14922
10:54:28,916 --> 10:54:29,916
all these root servers are
14923
10:54:31,980 --> 10:54:32,980
some examples of globaldomainsr.com or
14924
10:54:36,500 --> 10:54:37,500
netgov.edu country codes US Canada
14925
10:54:40,560 --> 10:54:41,560
CN
14926
10:54:42,000 --> 10:54:43,000
oh I don't know Denmark France Japan
14927
10:54:46,980 --> 10:54:47,980
CN oh that's going to annoy me now I'll
14928
10:54:48,596 --> 10:54:49,596
have to look when I finish this
14929
10:54:49,560 --> 10:54:50,560
presentation if he comes to me I'll say
14930
10:54:52,620 --> 10:54:53,620
uh you wouldn't be tested on that by the
14931
10:54:54,240 --> 10:54:55,240
way uh DNS root servers also known as
14932
10:54:57,360 --> 10:54:58,360
root name servers if anyone says that to
14933
10:54:59,700 --> 10:55:00,700
you it's perfectly um fine for them to
14934
10:55:02,040 --> 10:55:03,040
say that and it describes where the
14935
10:55:04,256 --> 10:55:05,256
authoritative did a service for the T
14936
10:55:06,596 --> 10:55:07,596
top level domains are located
14937
10:55:10,080 --> 10:55:11,080
please give answers for specified set of
14938
10:55:12,240 --> 10:55:13,240
zones from its own source so it doesn't
14939
10:55:14,460 --> 10:55:15,460
have anywhere else to go if there isn't
14940
10:55:16,860 --> 10:55:17,860
a response something's gone wrong
14941
10:55:19,740 --> 10:55:20,740
or the domain doesn't exist
14942
10:55:22,700 --> 10:55:23,700
at the moment and you'll you'll get some
14943
10:55:24,960 --> 10:55:25,960
sort of timeout message on your web
14944
10:55:26,520 --> 10:55:27,520
browser
14945
10:55:28,460 --> 10:55:29,460
non-authoritative servers these provide
14946
10:55:30,720 --> 10:55:31,720
cash dancers or Cash Aid I know some
14947
10:55:33,360 --> 10:55:34,360
people say that are obtained from
14948
10:55:35,096 --> 10:55:36,096
another name server
14949
10:55:36,840 --> 10:55:37,840
so as I said you've got the uh the root
14950
10:55:39,960 --> 10:55:40,960
servers here
14951
10:55:43,020 --> 10:55:44,020
and then
14952
10:55:45,120 --> 10:55:46,120
other companies large organizations just
14953
10:55:48,000 --> 10:55:49,000
to save traffic and time can query these
14954
10:55:51,256 --> 10:55:52,256
and then if they so wish
14955
10:55:55,020 --> 10:55:56,020
they could also be queried by other
14956
10:55:57,540 --> 10:55:58,540
servers and so on and so on and so on
14957
10:56:02,936 --> 10:56:03,936
the DNS is composed of a namespace this
14958
10:56:06,060 --> 10:56:07,060
is distributed database it contains the
14959
10:56:08,460 --> 10:56:09,460
data that includes the host names
14960
10:56:11,300 --> 10:56:12,300
if you recognize the structure there
14961
10:56:13,620 --> 10:56:14,620
it's similar to a file system in Unix
14962
10:56:17,820 --> 10:56:18,820
the name server translates the domain
14963
10:56:19,860 --> 10:56:20,860
name to its corresponding IP address and
14964
10:56:21,720 --> 10:56:22,720
we've seen an example of that
14965
10:56:23,880 --> 10:56:24,880
does the response to the DNS query it
14966
10:56:26,276 --> 10:56:27,276
receives from resolvers or the name
14967
10:56:28,256 --> 10:56:29,256
servers I'm going to talk about
14968
10:56:30,300 --> 10:56:31,300
um
14969
10:56:31,860 --> 10:56:32,860
to our resolvers in a minute I think I'm
14970
10:56:34,560 --> 10:56:35,560
not sure which slide it is
14971
10:56:36,596 --> 10:56:37,596
so the answers to the DNS queries are
14972
10:56:38,640 --> 10:56:39,640
based upon the contents of the name
14973
10:56:40,320 --> 10:56:41,320
server database so obviously the
14974
10:56:42,300 --> 10:56:43,300
database is full of records of um
14975
10:56:45,840 --> 10:56:46,840
mappings so um
14976
10:56:48,916 --> 10:56:49,916
x.com and it will be mapped to
14977
10:56:55,140 --> 10:56:56,140
there's a lot more than this but as a
14978
10:56:57,060 --> 10:56:58,060
simplified illustration
14979
10:56:59,276 --> 10:57:00,276
cached information is learned by the
14980
10:57:01,140 --> 10:57:02,140
name server from other name servers how
14981
10:57:03,776 --> 10:57:04,776
often they update the cache uh just
14982
10:57:05,640 --> 10:57:06,640
depends on obviously their local
14983
10:57:07,436 --> 10:57:08,436
configurations
14984
10:57:09,416 --> 10:57:10,416
now you can get an authoritative answer
14985
10:57:11,276 --> 10:57:12,276
this is based on the contents of the
14986
10:57:13,500 --> 10:57:14,500
name server database if it's a cached
14987
10:57:16,560 --> 10:57:17,560
answer it's known as non-authoritative
14988
10:57:19,200 --> 10:57:20,200
now on your PC you can issue
14989
10:57:24,916 --> 10:57:25,916
ip
14990
10:57:26,776 --> 10:57:27,776
config and this has worked for me before
14991
10:57:29,480 --> 10:57:30,480
and forward slash
14992
10:57:32,960 --> 10:57:33,960
flush DNS say I've moved my my website
14993
10:57:38,040 --> 10:57:39,040
from one hosting company which I have
14994
10:57:39,840 --> 10:57:40,840
done in the past to another
14995
10:57:43,620 --> 10:57:44,620
I can um I can force a flush to find out
14996
10:57:47,096 --> 10:57:48,096
where to to see if this
14997
10:57:49,560 --> 10:57:50,560
um it's been moved correctly
14998
10:57:51,960 --> 10:57:52,960
and obviously I could put the IP address
14999
10:57:53,756 --> 10:57:54,756
in
15000
10:57:57,360 --> 10:57:58,360
but this is quite a stressful time if
15001
10:57:59,276 --> 10:58:00,276
you own a business because you've got
15002
10:58:00,960 --> 10:58:01,960
your website
15003
10:58:02,096 --> 10:58:03,096
um technically in two places although
15004
10:58:03,540 --> 10:58:04,540
this is the old version and eventually
15005
10:58:06,480 --> 10:58:07,480
the records will update but uh could
15006
10:58:09,060 --> 10:58:10,060
possibly be asked in the exam ipconfig
15007
10:58:11,880 --> 10:58:12,880
uh forward slash flush DNS and try it at
15008
10:58:14,820 --> 10:58:15,820
home if you like
15009
10:58:17,160 --> 10:58:18,160
what's the DNS composed of as resolvo is
15010
10:58:20,580 --> 10:58:21,580
the next part which I mentioned it's a
15011
10:58:22,560 --> 10:58:23,560
software component that comes bundled
15012
10:58:24,120 --> 10:58:25,120
with your operating system also in
15013
10:58:26,756 --> 10:58:27,756
network Hardware
15014
10:58:30,540 --> 10:58:31,540
the internet applications such as web
15015
10:58:32,640 --> 10:58:33,640
browsers and email clients need a domain
15016
10:58:34,680 --> 10:58:35,680
name lookup so this is a piece of
15017
10:58:37,916 --> 10:58:38,916
software that um issues the DNS request
15018
10:58:44,340 --> 10:58:45,340
the resolver accepts the DNS queries and
15019
10:58:46,916 --> 10:58:47,916
if the required information is available
15020
10:58:48,540 --> 10:58:49,540
in the local cache it returns that data
15021
10:58:51,120 --> 10:58:52,120
to the client so your PC will use the
15022
10:58:53,880 --> 10:58:54,880
resolver
15023
10:58:55,560 --> 10:58:56,560
a piece of little piece of software
15024
10:58:57,240 --> 10:58:58,240
somewhere
15025
10:59:00,596 --> 10:59:01,596
then it will go out to the internet and
15026
10:59:03,480 --> 10:59:04,480
obviously return it so then you can
15027
10:59:05,520 --> 10:59:06,520
issue the ping which we already saw
15028
10:59:09,660 --> 10:59:10,660
and it's not available it sends the
15029
10:59:11,276 --> 10:59:12,276
query to the name server
15030
10:59:14,400 --> 10:59:15,400
when the resolver resumes the name
15031
10:59:16,080 --> 10:59:17,080
server's response it hands the result to
15032
10:59:17,700 --> 10:59:18,700
the application that initiated the
15033
10:59:19,256 --> 10:59:20,256
request so this will be your web browser
15034
10:59:21,540 --> 10:59:22,540
email
15035
10:59:23,220 --> 10:59:24,220
um email package whatever you've already
15036
10:59:25,020 --> 10:59:26,020
in obviously most of us are in our email
15037
10:59:26,756 --> 10:59:27,756
off the cloud now like um
15038
10:59:29,580 --> 10:59:30,580
Gmail
15039
10:59:31,500 --> 10:59:32,500
so internet application sends a query
15040
10:59:33,596 --> 10:59:34,596
for translating the sampler company
15041
10:59:37,320 --> 10:59:38,320
resolver checks the local cash so you
15042
10:59:39,540 --> 10:59:40,540
you could actually check your DNS cache
15043
10:59:41,936 --> 10:59:42,936
on your home computer
15044
10:59:45,776 --> 10:59:46,776
if it's not available then it hands over
15045
10:59:47,400 --> 10:59:48,400
to the result the resolver hands it over
15046
10:59:49,380 --> 10:59:50,380
to the nearest name server which would
15047
10:59:51,060 --> 10:59:52,060
be normally your ISP
15048
10:59:54,180 --> 10:59:55,180
name serversy determines whether it can
15049
10:59:56,580 --> 10:59:57,580
provide the data
15050
10:59:59,640 --> 11:00:00,640
if it's not available then it goes all
15051
11:00:01,500 --> 11:00:02,500
the way off
15052
11:00:02,820 --> 11:00:03,820
so PC
15053
11:00:05,700 --> 11:00:06,700
resolver
15054
11:00:08,936 --> 11:00:09,936
which basically just checks your your
15055
11:00:11,640 --> 11:00:12,640
DNS
15056
11:00:13,800 --> 11:00:14,800
cash on your home computer if not it'll
15057
11:00:18,060 --> 11:00:19,060
go off to your ISP if the ISP doesn't
15058
11:00:21,300 --> 11:00:22,300
know
15059
11:00:22,256 --> 11:00:23,256
it could query another server but let's
15060
11:00:24,360 --> 11:00:25,360
just say it goes off to the the air
15061
11:00:26,820 --> 11:00:27,820
route there so this would all happen
15062
11:00:29,160 --> 11:00:30,160
pretty quickly obviously you've you know
15063
11:00:32,460 --> 11:00:33,460
yourself you've put in a URL and just
15064
11:00:34,800 --> 11:00:35,800
sat there in how we're so impatient
15065
11:00:38,220 --> 11:00:39,220
nowadays you sat there in any more than
15066
11:00:39,960 --> 11:00:40,960
five seconds you start hitting the
15067
11:00:41,880 --> 11:00:42,880
refresh button
15068
11:00:44,580 --> 11:00:45,580
all right so the name server ask the.com
15069
11:00:46,560 --> 11:00:47,560
name server and gets finally gets the IP
15070
11:00:48,596 --> 11:00:49,596
address
15071
11:00:49,800 --> 11:00:50,800
since the sample company has the IP
15072
11:00:51,776 --> 11:00:52,776
address in its own database uh this this
15073
11:00:54,180 --> 11:00:55,180
would be for a new domain I guess the
15074
11:00:56,820 --> 11:00:57,820
name server that requested the IP
15075
11:00:58,320 --> 11:00:59,320
address now gets an authoritative IP
15076
11:01:00,480 --> 11:01:01,480
address as the answer
15077
11:01:02,096 --> 11:01:03,096
and that's all finally relayed
15078
11:01:04,436 --> 11:01:05,436
you could have a couple of query types a
15079
11:01:06,776 --> 11:01:07,776
query received by the name server this
15080
11:01:09,416 --> 11:01:10,416
is a recursive query this is received by
15081
11:01:12,120 --> 11:01:13,120
the uh received from the resolver
15082
11:01:14,840 --> 11:01:15,840
non-recursive is received by other
15083
11:01:17,096 --> 11:01:18,096
servers so they could just be doing an
15084
11:01:19,800 --> 11:01:20,800
update of their own records
15085
11:01:23,820 --> 11:01:24,820
uh probably in the exam you'll be asked
15086
11:01:26,580 --> 11:01:27,580
a little bit about what are DNS records
15087
11:01:28,916 --> 11:01:29,916
what do they consist of
15088
11:01:31,620 --> 11:01:32,620
also known as resource records these
15089
11:01:34,080 --> 11:01:35,080
have the information that we need to do
15090
11:01:36,000 --> 11:01:37,000
the resolving
15091
11:01:38,276 --> 11:01:39,276
the records map a domain to its ipv4
15092
11:01:41,040 --> 11:01:42,040
address these are a records
15093
11:01:44,220 --> 11:01:45,220
so this is the type of question you
15094
11:01:45,960 --> 11:01:46,960
might get asked what has an a record it
15095
11:01:48,120 --> 11:01:49,120
maps The Domain to its high people for
15096
11:01:50,820 --> 11:01:51,820
address
15097
11:01:52,320 --> 11:01:53,320
so here's an example you would put these
15098
11:01:55,860 --> 11:01:56,860
in when you register your domain name if
15099
11:01:58,680 --> 11:01:59,680
you host with the same company that you
15100
11:02:00,596 --> 11:02:01,596
register so there's a company called one
15101
11:02:03,960 --> 11:02:04,960
two three reg dot Co dot UK that I used
15102
11:02:08,276 --> 11:02:09,276
to register my names with and host so I
15103
11:02:12,240 --> 11:02:13,240
think it was all done for me there
15104
11:02:15,240 --> 11:02:16,240
now some of these domain names
15105
11:02:17,820 --> 11:02:18,820
um say in
15106
11:02:19,380 --> 11:02:20,380
60 days.com
15107
11:02:23,580 --> 11:02:24,580
I um had it registered here but it's
15108
11:02:27,180 --> 11:02:28,180
actually hosted somewhere else now so
15109
11:02:29,520 --> 11:02:30,520
about to go in and
15110
11:02:31,860 --> 11:02:32,860
um I actually put the name server that's
15111
11:02:33,360 --> 11:02:34,360
the only part I've put in but there's a
15112
11:02:35,580 --> 11:02:36,580
there's other records I can manipulate
15113
11:02:37,680 --> 11:02:38,680
and as the owner of this domain I can do
15114
11:02:40,320 --> 11:02:41,320
that but just be very careful what you
15115
11:02:42,300 --> 11:02:43,300
do if you don't know what you're doing
15116
11:02:43,980 --> 11:02:44,980
then you need to ask for help because
15117
11:02:45,960 --> 11:02:46,960
things can go wrong because as I've told
15118
11:02:48,180 --> 11:02:49,180
you you can split
15119
11:02:49,980 --> 11:02:50,980
your mail
15120
11:02:52,680 --> 11:02:53,680
to go to oneip address your
15121
11:02:56,220 --> 11:02:57,220
um your web server can be hosted on
15122
11:02:59,520 --> 11:03:00,520
another IP address you've got to have
15123
11:03:01,080 --> 11:03:02,080
records for all of this
15124
11:03:03,776 --> 11:03:04,776
so example of an a record first is used
15125
11:03:06,900 --> 11:03:07,900
to take care of situations when someone
15126
11:03:08,640 --> 11:03:09,640
tries to access the domain name without
15127
11:03:11,096 --> 11:03:12,096
typing www most of us don't bother now
15128
11:03:14,460 --> 11:03:15,460
so it'll resolved correctly the the
15129
11:03:16,680 --> 11:03:17,680
first one being
15130
11:03:18,960 --> 11:03:19,960
they say ah sorry
15131
11:03:20,936 --> 11:03:21,936
so somebody hasn't put www
15132
11:03:24,360 --> 11:03:25,360
and this is um this is a wild card so
15133
11:03:26,756 --> 11:03:27,756
anything before your domain name is just
15134
11:03:29,756 --> 11:03:30,756
going to go to and whatever server
15135
11:03:31,800 --> 11:03:32,800
they're hosting it on here
15136
11:03:37,080 --> 11:03:38,080
the second record we saw is the wild
15137
11:03:38,936 --> 11:03:39,936
card it will direct any subdomains to
15138
11:03:41,160 --> 11:03:42,160
the hosting server if you so wish you
15139
11:03:43,500 --> 11:03:44,500
can then point it off somewhere else or
15140
11:03:46,380 --> 11:03:47,380
you can add it into the DNA DNS records
15141
11:03:50,540 --> 11:03:51,540
the quadrupalade if there's any quick
15142
11:03:53,400 --> 11:03:54,400
way of saying this actually AAA oh could
15143
11:03:56,640 --> 11:03:57,640
you play
15144
11:03:57,960 --> 11:03:58,960
because um over in Australia this means
15145
11:04:01,200 --> 11:04:02,200
the Australian
15146
11:04:02,700 --> 11:04:03,700
um Automobile Association I know it's
15147
11:04:04,916 --> 11:04:05,916
Triple A we've got over here so you're
15148
11:04:06,960 --> 11:04:07,960
just gonna be careful what if anyone
15149
11:04:08,700 --> 11:04:09,700
else is using these uh letters
15150
11:04:12,240 --> 11:04:13,240
this is an IPv6 address that maps The
15151
11:04:14,520 --> 11:04:15,520
Domain to its IPv6 address obvious
15152
11:04:16,916 --> 11:04:17,916
obviously because um we need to be we're
15153
11:04:20,276 --> 11:04:21,276
moving to IPv6 now
15154
11:04:22,256 --> 11:04:23,256
so the 128-bit address
15155
11:04:25,800 --> 11:04:26,800
there's an MX record which you probably
15156
11:04:28,380 --> 11:04:29,380
won't be touching unless you're doing
15157
11:04:31,080 --> 11:04:32,080
your own mail stuff
15158
11:04:32,700 --> 11:04:33,700
to Maps the domain name to an email
15159
11:04:34,380 --> 11:04:35,380
server if you're working for a big
15160
11:04:36,360 --> 11:04:37,360
company they'll take care of that
15161
11:04:38,160 --> 11:04:39,160
but looking at the MX record we could
15162
11:04:39,776 --> 11:04:40,776
identify the mail server to which the
15163
11:04:41,580 --> 11:04:42,580
emails are sent
15164
11:04:44,340 --> 11:04:45,340
uh C name conical name record
15165
11:04:48,720 --> 11:04:49,720
used to specify a domain name or
15166
11:04:50,400 --> 11:04:51,400
subdomain as an alias of another domain
15167
11:04:54,720 --> 11:04:55,720
so it allows the mapping of a domain to
15168
11:04:57,240 --> 11:04:58,240
another domain
15169
11:04:59,340 --> 11:05:00,340
so for example
15170
11:05:01,500 --> 11:05:02,500
um
15171
11:05:02,580 --> 11:05:03,580
you complete subdomains such as the mail
15172
11:05:04,980 --> 11:05:05,980
or your FTP to your main address and you
15173
11:05:08,936 --> 11:05:09,936
can do you could do this to make your
15174
11:05:10,200 --> 11:05:11,200
company look bigger
15175
11:05:12,120 --> 11:05:13,120
and I think my FTP certainly just points
15176
11:05:15,596 --> 11:05:16,596
to my my normal server
15177
11:05:19,380 --> 11:05:20,380
yeah but obviously when you're doing FTP
15178
11:05:21,900 --> 11:05:22,900
you need to specify
15179
11:05:24,060 --> 11:05:25,060
um in your software that you're using
15180
11:05:26,756 --> 11:05:27,756
FTP so this that was that's how it would
15181
11:05:29,340 --> 11:05:30,340
work
15182
11:05:30,776 --> 11:05:31,776
so there must be an a record for the
15183
11:05:32,220 --> 11:05:33,220
hosting server before aliases can be
15184
11:05:34,800 --> 11:05:35,800
added
15185
11:05:36,900 --> 11:05:37,900
so cname aliases must point to another
15186
11:05:39,596 --> 11:05:40,596
domain
15187
11:05:40,800 --> 11:05:41,800
so if somebody types
15188
11:05:43,080 --> 11:05:44,080
um
15189
11:05:44,000 --> 11:05:45,000
bar.example.com there's a cname record
15190
11:05:47,640 --> 11:05:48,640
that basically says that is actually on
15191
11:05:51,660 --> 11:05:52,660
um
15192
11:05:53,040 --> 11:05:54,040
the C name is food.example.com then the
15193
11:05:56,756 --> 11:05:57,756
the search takes place the DNS search
15194
11:05:59,040 --> 11:06:00,040
takes place for food.example.com there's
15195
11:06:02,520 --> 11:06:03,520
an a record so IP B4 record and it's
15196
11:06:06,720 --> 11:06:07,720
saying yeah this is posted on this
15197
11:06:09,300 --> 11:06:10,300
particular server
15198
11:06:13,020 --> 11:06:14,020
PTR records pointers Maps like pv4
15199
11:06:17,040 --> 11:06:18,040
address to a clinical name for the
15200
11:06:18,900 --> 11:06:19,900
purposes of the reverse DNS lookup
15201
11:06:21,900 --> 11:06:22,900
so this is uh the reverse so normally we
15202
11:06:24,840 --> 11:06:25,840
do
15203
11:06:25,980 --> 11:06:26,980
um
15204
11:06:27,620 --> 11:06:28,620
xyz.com and that goes to
15205
11:06:33,900 --> 11:06:34,900
but the reverse can happen somebody
15206
11:06:35,880 --> 11:06:36,880
could type
15207
11:06:37,276 --> 11:06:38,276
192.1.1.1 when you type that in your
15208
11:06:39,660 --> 11:06:40,660
browser I think
15209
11:06:42,840 --> 11:06:43,840
you um
15210
11:06:45,060 --> 11:06:46,060
I need to test that actually
15211
11:06:47,340 --> 11:06:48,340
it won't stay so if you if you type that
15212
11:06:49,916 --> 11:06:50,916
you may well see it actually resolves to
15213
11:06:52,200 --> 11:06:53,200
this
15214
11:06:53,040 --> 11:06:54,040
might depend on your browser software
15215
11:06:56,040 --> 11:06:57,040
SOA State start of authority record it's
15216
11:06:58,860 --> 11:06:59,860
the first record in the zone file it
15217
11:07:01,436 --> 11:07:02,436
declares it contains the most
15218
11:07:03,300 --> 11:07:04,300
authoritative information for the zone
15219
11:07:09,480 --> 11:07:10,480
information is the email address of the
15220
11:07:12,020 --> 11:07:13,020
administrator you normally have to put
15221
11:07:13,980 --> 11:07:14,980
something in unless you want it to be
15222
11:07:15,360 --> 11:07:16,360
private the name of the primary DNS
15223
11:07:18,120 --> 11:07:19,120
server there's a serial number time
15224
11:07:20,936 --> 11:07:21,936
Fields when it was all registered and on
15225
11:07:22,980 --> 11:07:23,980
their last updates
15226
11:07:25,320 --> 11:07:26,320
uh two of the types of Records static is
15227
11:07:27,660 --> 11:07:28,660
when it's done manually
15228
11:07:30,060 --> 11:07:31,060
here and dynamic it's automatically
15229
11:07:33,360 --> 11:07:34,360
updated there's two types of Records
15230
11:07:37,916 --> 11:07:38,916
and Dynamic DNS this is a process of
15231
11:07:42,360 --> 11:07:43,360
automatically
15232
11:07:43,740 --> 11:07:44,740
um updating a Dynamic DNS record in the
15233
11:07:46,500 --> 11:07:47,500
name server what can happen is this is
15234
11:07:48,900 --> 11:07:49,900
all almost
15235
11:07:51,416 --> 11:07:52,416
in real time
15236
11:07:53,580 --> 11:07:54,580
could well be used if you're using cloud
15237
11:07:57,020 --> 11:07:58,020
computing and your setting up servers
15238
11:08:00,740 --> 11:08:01,740
tearing down servers moving information
15239
11:08:04,580 --> 11:08:05,580
Dynamic DNS
15240
11:08:08,580 --> 11:08:09,580
will update the lap information and the
15241
11:08:11,936 --> 11:08:12,936
um names
15242
11:08:18,000 --> 11:08:19,000
so useful when the IP addresses of our
15243
11:08:20,096 --> 11:08:21,096
devices keep changing
15244
11:08:24,960 --> 11:08:25,960
uh whenever a client computer using DHCP
15245
11:08:27,720 --> 11:08:28,720
gets a new IP address it can use Dynamic
15246
11:08:29,700 --> 11:08:30,700
DNS
15247
11:08:31,800 --> 11:08:32,800
all right so we covered a lot of stuff
15248
11:08:33,180 --> 11:08:34,180
you know the core stuff about root
15249
11:08:35,520 --> 11:08:36,520
servers and AE records and quadruple a
15250
11:08:38,220 --> 11:08:39,220
records I think that's the type of stuff
15251
11:08:40,020 --> 11:08:41,020
that has questions on
15252
11:08:42,320 --> 11:08:43,320
DNS domains fully quite fully qualified
15253
11:08:45,960 --> 11:08:46,960
domains root servers records a lot of
15254
11:08:50,096 --> 11:08:51,096
information and thanks for watching
15255
11:08:55,290 --> 11:08:56,290
[Music]
15256
11:09:03,740 --> 11:09:04,740
thank you
15257
11:09:11,460 --> 11:09:12,460
welcome to module 6 lesson 7 proxy
15258
11:09:14,220 --> 11:09:15,220
servers
15259
11:09:17,756 --> 11:09:18,756
objectives we're looking at what a proxy
15260
11:09:19,620 --> 11:09:20,620
server is an introduction uh the uses of
15261
11:09:23,220 --> 11:09:24,220
proxy servers and forward proxy servers
15262
11:09:26,096 --> 11:09:27,096
reverse proxy servers
15263
11:09:28,916 --> 11:09:29,916
so you may have actually heard of these
15264
11:09:30,960 --> 11:09:31,960
before especially if you've worked in an
15265
11:09:32,640 --> 11:09:33,640
office whereby
15266
11:09:34,560 --> 11:09:35,560
instead of connecting directly out to
15267
11:09:36,720 --> 11:09:37,720
the internet your settings will be
15268
11:09:38,640 --> 11:09:39,640
searched that you'll connect to a proxy
15269
11:09:40,916 --> 11:09:41,916
server especially
15270
11:09:43,256 --> 11:09:44,256
um for getting out to surfing websites
15271
11:09:46,436 --> 11:09:47,436
the proxy server will do a few things
15272
11:09:49,020 --> 11:09:50,020
which we'll look at in a bit
15273
11:09:53,096 --> 11:09:54,096
so it's in a mediator or an intermediary
15274
11:09:56,756 --> 11:09:57,756
between you and some other service
15275
11:10:00,720 --> 11:10:01,720
you've got the client computer the
15276
11:10:02,460 --> 11:10:03,460
destination server and then obviously
15277
11:10:03,960 --> 11:10:04,960
the proxy in the middle
15278
11:10:05,520 --> 11:10:06,520
here's an illustration here which we'll
15279
11:10:08,040 --> 11:10:09,040
talk about the caching and web filter in
15280
11:10:10,980 --> 11:10:11,980
so it's mainly uh used for uh surfing
15281
11:10:15,660 --> 11:10:16,660
when you want to go out and surf the web
15282
11:10:17,700 --> 11:10:18,700
for whatever reason it can then filter
15283
11:10:20,880 --> 11:10:21,880
what sites you can and can't connect to
15284
11:10:24,300 --> 11:10:25,300
it's um
15285
11:10:26,160 --> 11:10:27,160
caches some of the content so it's got a
15286
11:10:28,620 --> 11:10:29,620
copy of regularly visited our websites
15287
11:10:32,756 --> 11:10:33,756
to speed up the um
15288
11:10:34,560 --> 11:10:35,560
the surfing experience for you
15289
11:10:38,520 --> 11:10:39,520
makes requests on behalf of the client
15290
11:10:40,560 --> 11:10:41,560
computer so you're sending the request
15291
11:10:42,840 --> 11:10:43,840
out to you to what you think is the
15292
11:10:44,700 --> 11:10:45,700
internet but it's going to the proxy and
15293
11:10:46,740 --> 11:10:47,740
then the proxy design your behalf the
15294
11:10:48,840 --> 11:10:49,840
proxy receives a response from whichever
15295
11:10:50,820 --> 11:10:51,820
server say the web server on the
15296
11:10:52,560 --> 11:10:53,560
internet and then sends that information
15297
11:10:54,240 --> 11:10:55,240
back to you
15298
11:10:58,256 --> 11:10:59,256
so it intercepts the communication
15299
11:11:00,960 --> 11:11:01,960
between the client's computer and the
15300
11:11:02,820 --> 11:11:03,820
destination server
15301
11:11:04,560 --> 11:11:05,560
I've already mentioned that you don't
15302
11:11:06,120 --> 11:11:07,120
actually directly connect to the
15303
11:11:07,256 --> 11:11:08,256
destination you can have different proxy
15304
11:11:10,020 --> 11:11:11,020
servers to serve different traffic needs
15305
11:11:13,200 --> 11:11:14,200
you might have a proxy server to handle
15306
11:11:15,360 --> 11:11:16,360
only HTTP and then if you're doing FTP
15307
11:11:18,740 --> 11:11:19,740
then it may handle those requests and on
15308
11:11:22,680 --> 11:11:23,680
a different server
15309
11:11:25,620 --> 11:11:26,620
what does it do it increases performance
15310
11:11:27,720 --> 11:11:28,720
so
15311
11:11:29,340 --> 11:11:30,340
um it's mainly due to caching or you may
15312
11:11:31,800 --> 11:11:32,800
have quite a powerful proxy server
15313
11:11:34,436 --> 11:11:35,436
that's done doing all these requests for
15314
11:11:36,240 --> 11:11:37,240
you
15315
11:11:37,380 --> 11:11:38,380
increases security because what the
15316
11:11:40,080 --> 11:11:41,080
outside servers on the web see is the
15317
11:11:42,720 --> 11:11:43,720
connection coming from the proxy are not
15318
11:11:45,360 --> 11:11:46,360
actually and the uh the client device or
15319
11:11:48,360 --> 11:11:49,360
the host device
15320
11:11:50,096 --> 11:11:51,096
it also as I said caches content so it
15321
11:11:53,220 --> 11:11:54,220
can serve up and saved copies of a
15322
11:11:58,200 --> 11:11:59,200
website it could be a News website or
15323
11:12:00,300 --> 11:12:01,300
something else that may not um be
15324
11:12:02,936 --> 11:12:03,936
updated too regularly and then whatever
15325
11:12:05,400 --> 11:12:06,400
these rules are on that proxy server it
15326
11:12:08,460 --> 11:12:09,460
will refresh that content at given
15327
11:12:11,160 --> 11:12:12,160
intervals
15328
11:12:13,140 --> 11:12:14,140
so you've got to be careful sometimes
15329
11:12:14,700 --> 11:12:15,700
you can actually be served up a cache of
15330
11:12:16,980 --> 11:12:17,980
a web page and the actual live website
15331
11:12:19,740 --> 11:12:20,740
has changed so it's something to bear in
15332
11:12:22,140 --> 11:12:23,140
mind when you're configuring this on
15333
11:12:24,180 --> 11:12:25,180
your network if you do it
15334
11:12:32,596 --> 11:12:33,596
crazy security as well filters our
15335
11:12:35,700 --> 11:12:36,700
unwanted web traffic malicious files
15336
11:12:37,916 --> 11:12:38,916
before sending that onto the end client
15337
11:12:41,756 --> 11:12:42,756
if the client tries to download a
15338
11:12:44,756 --> 11:12:45,756
malicious file unknowingly the proxy
15339
11:12:46,980 --> 11:12:47,980
server can filter it out and you can
15340
11:12:48,960 --> 11:12:49,960
have a firewall in between your proxy
15341
11:12:51,540 --> 11:12:52,540
server and a client or between the proxy
15342
11:12:55,080 --> 11:12:56,080
server and the internet or both
15343
11:12:57,060 --> 11:12:58,060
depending on what your requirements are
15344
11:13:00,060 --> 11:13:01,060
so already covered that actually
15345
11:13:03,120 --> 11:13:04,120
a forward proxy server is a new thing on
15346
11:13:06,360 --> 11:13:07,360
this syllabus it acts on behalf of a
15347
11:13:08,820 --> 11:13:09,820
client computer it gets the requested
15348
11:13:11,096 --> 11:13:12,096
information from different servers
15349
11:13:14,040 --> 11:13:15,040
servers on the Internet only interact
15350
11:13:15,960 --> 11:13:16,960
with the proxy server and they don't
15351
11:13:17,580 --> 11:13:18,580
know about the client's existence which
15352
11:13:19,740 --> 11:13:20,740
is the concept we've already been
15353
11:13:21,000 --> 11:13:22,000
discussing now there's something
15354
11:13:24,000 --> 11:13:25,000
um known as a reverse proxy server
15355
11:13:27,000 --> 11:13:28,000
and the clues in the title I suppose it
15356
11:13:29,640 --> 11:13:30,640
acts on behalf of the servers on the
15357
11:13:31,320 --> 11:13:32,320
inside of an organization but you can
15358
11:13:34,020 --> 11:13:35,020
see here
15359
11:13:35,096 --> 11:13:36,096
some host on the Internet is trying to
15360
11:13:38,160 --> 11:13:39,160
access your web server internally and
15361
11:13:41,340 --> 11:13:42,340
the proxy server will act as the
15362
11:13:42,840 --> 11:13:43,840
intermediary deciding what does and
15363
11:13:44,936 --> 11:13:45,936
doesn't go out and also obviously it
15364
11:13:47,096 --> 11:13:48,096
will could have cached copies of what's
15365
11:13:49,620 --> 11:13:50,620
actually on the web server the actual
15366
11:13:52,200 --> 11:13:53,200
web server on the inside
15367
11:13:56,096 --> 11:13:57,096
so um since the service is behind the
15368
11:13:58,256 --> 11:13:59,256
proxy server the following is true the
15369
11:14:00,480 --> 11:14:01,480
client is not aware of the services
15370
11:14:02,060 --> 11:14:03,060
existence this is the internet client
15371
11:14:04,256 --> 11:14:05,256
wherever that may be and it treats a
15372
11:14:06,416 --> 11:14:07,416
proxy server as the origin
15373
11:14:09,840 --> 11:14:10,840
foreign it can also be used to balance
15374
11:14:12,720 --> 11:14:13,720
the load under server farm so it can
15375
11:14:14,756 --> 11:14:15,756
pull different servers at the same time
15376
11:14:18,120 --> 11:14:19,120
or load balance
15377
11:14:21,960 --> 11:14:22,960
now the servers are considered to be on
15378
11:14:24,000 --> 11:14:25,000
the server side of the internet because
15379
11:14:26,276 --> 11:14:27,276
of the following The Intercept all the
15380
11:14:28,380 --> 11:14:29,380
traffic coming from the internet they
15381
11:14:30,240 --> 11:14:31,240
make it more difficult for hackers not
15382
11:14:31,980 --> 11:14:32,980
impossible but more difficult to get to
15383
11:14:34,020 --> 11:14:35,020
get the details of the internal Network
15384
11:14:38,340 --> 11:14:39,340
all right so in brief we've covered
15385
11:14:40,560 --> 11:14:41,560
proxies and introduction the uses of
15386
11:14:43,200 --> 11:14:44,200
them forward proxy servers and reverse
15387
11:14:46,020 --> 11:14:47,020
proxy servers
15388
11:14:47,520 --> 11:14:48,520
all right that's all for now thanks for
15389
11:14:49,436 --> 11:14:50,436
watching
15390
11:14:55,290 --> 11:14:56,290
[Music]
15391
11:15:11,700 --> 11:15:12,700
welcome to the lesson on network address
15392
11:15:13,916 --> 11:15:14,916
translation on Nat for short
15393
11:15:18,416 --> 11:15:19,416
and a look at what it is ipv4 addresses
15394
11:15:21,916 --> 11:15:22,916
IPv6 addresses
15395
11:15:24,480 --> 11:15:25,480
benefit of having NASA using it
15396
11:15:27,960 --> 11:15:28,960
Source Network address translation
15397
11:15:30,060 --> 11:15:31,060
destination that and port address
15398
11:15:32,880 --> 11:15:33,880
translation or also called Pat or Nat
15399
11:15:36,660 --> 11:15:37,660
overload
15400
11:15:38,720 --> 11:15:39,720
so what is in that
15401
11:15:42,240 --> 11:15:43,240
it basically translates in private IP
15402
11:15:44,820 --> 11:15:45,820
addresses into public IP for addresses
15403
11:15:47,460 --> 11:15:48,460
the private IP for addresses
15404
11:15:51,300 --> 11:15:52,300
um
15405
11:15:52,580 --> 11:15:53,580
RFC 1918 I think it is these provide
15406
11:15:56,776 --> 11:15:57,776
addresses that you can use internally on
15407
11:15:59,340 --> 11:16:00,340
your network but they can't be routed
15408
11:16:00,960 --> 11:16:01,960
over the Internet so all of a sudden
15409
11:16:02,936 --> 11:16:03,936
you've got a problem
15410
11:16:04,340 --> 11:16:05,340
so this helped solve the issue of
15411
11:16:07,560 --> 11:16:08,560
running out of ipv4 addresses however
15412
11:16:10,200 --> 11:16:11,200
then we have to resolve the issue of not
15413
11:16:11,936 --> 11:16:12,936
being able to wrote route those
15414
11:16:13,500 --> 11:16:14,500
addresses
15415
11:16:16,140 --> 11:16:17,140
so and that is a router function
15416
11:16:18,180 --> 11:16:19,180
actually these routers and firewalls can
15417
11:16:21,060 --> 11:16:22,060
do nothing
15418
11:16:24,240 --> 11:16:25,240
so normally it's enabled at the boundary
15419
11:16:26,520 --> 11:16:27,520
where your local area network meets your
15420
11:16:28,740 --> 11:16:29,740
internet connection
15421
11:16:31,220 --> 11:16:32,220
you don't need to bother not in usually
15422
11:16:33,776 --> 11:16:34,776
internally on your network no particular
15423
11:16:35,580 --> 11:16:36,580
reason and we use Nat with ipv4
15424
11:16:38,400 --> 11:16:39,400
addresses
15425
11:16:39,720 --> 11:16:40,720
ipv4 has approximately 4.3 billion
15426
11:16:43,620 --> 11:16:44,620
unfortunately the DraStic growth of the
15427
11:16:45,900 --> 11:16:46,900
internet due to affordability of and and
15428
11:16:49,500 --> 11:16:50,500
user equipment basically I mean maybe we
15429
11:16:52,916 --> 11:16:53,916
were running out of ipv4 addresses
15430
11:16:55,860 --> 11:16:56,860
so Nat was a temporary solution to a
15431
11:16:59,756 --> 11:17:00,756
permanent problem
15432
11:17:03,320 --> 11:17:04,320
IPv6 is the replacement obviously for
15433
11:17:06,660 --> 11:17:07,660
ipv version 4. now this is the long-term
15434
11:17:10,380 --> 11:17:11,380
solution there is a version of nat
15435
11:17:13,020 --> 11:17:14,020
available for IPv6 I don't even think
15436
11:17:17,640 --> 11:17:18,640
Cisco included on the syllabus anymore
15437
11:17:19,380 --> 11:17:20,380
the reason is there's an almost
15438
11:17:21,596 --> 11:17:22,596
inexhaustible
15439
11:17:23,160 --> 11:17:24,160
number of available IP version 6
15440
11:17:26,276 --> 11:17:27,276
addresses
15441
11:17:28,080 --> 11:17:29,080
um I think something like Millions per
15442
11:17:30,240 --> 11:17:31,240
every per every person in the world so
15443
11:17:33,596 --> 11:17:34,596
it's pretty much inconceivable that
15444
11:17:35,340 --> 11:17:36,340
we're going to be running out of them
15445
11:17:37,200 --> 11:17:38,200
anytime soon certainly within our
15446
11:17:39,240 --> 11:17:40,240
lifetimes anyway
15447
11:17:41,096 --> 11:17:42,096
so it benefits as well as using it so we
15448
11:17:43,916 --> 11:17:44,916
don't really have addresses it actually
15449
11:17:45,360 --> 11:17:46,360
hides our internal addresses on our
15450
11:17:48,240 --> 11:17:49,240
private network from the internet which
15451
11:17:50,820 --> 11:17:51,820
is pretty handy so it's a security
15452
11:17:52,380 --> 11:17:53,380
feature
15453
11:17:54,360 --> 11:17:55,360
these are the private addresses which
15454
11:17:56,460 --> 11:17:57,460
hopefully you're already familiar with
15455
11:17:57,900 --> 11:17:58,900
you need to know this range of addresses
15456
11:18:00,060 --> 11:18:01,060
because this is a favorite exam topic
15457
11:18:02,756 --> 11:18:03,756
for comtier and also Cisco and Microsoft
15458
11:18:07,620 --> 11:18:08,620
these addresses you can arbitrarily
15459
11:18:09,840 --> 11:18:10,840
inside them with the dhp server inside
15460
11:18:12,596 --> 11:18:13,596
your network or
15461
11:18:14,936 --> 11:18:15,936
um yeah you'll have DHCP server
15462
11:18:17,700 --> 11:18:18,700
somewhere usually
15463
11:18:19,500 --> 11:18:20,500
I wouldn't let any users assign their
15464
11:18:21,300 --> 11:18:22,300
own IP addresses
15465
11:18:22,980 --> 11:18:23,980
so let's say we have a lan with
15466
11:18:24,480 --> 11:18:25,480
computers that assign these private IP
15467
11:18:26,340 --> 11:18:27,340
addresses and internally we've got a PC
15468
11:18:29,040 --> 11:18:30,040
one the data back it goes to our router
15469
11:18:31,680 --> 11:18:32,680
the router will Nat to this address for
15470
11:18:34,200 --> 11:18:35,200
a routable address which you've added to
15471
11:18:36,720 --> 11:18:37,720
the configuration somewhere
15472
11:18:38,820 --> 11:18:39,820
and it's one of the addresses you've
15473
11:18:40,140 --> 11:18:41,140
been allocated the packet goes out to
15474
11:18:42,416 --> 11:18:43,416
the internet somewhere comes back your
15475
11:18:45,300 --> 11:18:46,300
router will have a table and that
15476
11:18:47,096 --> 11:18:48,096
translation table
15477
11:18:48,840 --> 11:18:49,840
and it will recall which address on is
15478
11:18:51,480 --> 11:18:52,480
on the inside which is on the outside
15479
11:18:53,416 --> 11:18:54,416
and then
15480
11:18:55,256 --> 11:18:56,256
um re-nut it so it populates the packets
15481
11:18:57,660 --> 11:18:58,660
for the correct header and then forwards
15482
11:18:59,700 --> 11:19:00,700
it back to the
15483
11:19:01,560 --> 11:19:02,560
um PC on the inside of your LAN
15484
11:19:06,416 --> 11:19:07,416
so in this case this is in Long longer
15485
11:19:09,660 --> 11:19:10,660
version of what I've said really this
15486
11:19:11,640 --> 11:19:12,640
case the hudternetwork.com so if I have
15487
11:19:14,340 --> 11:19:15,340
the server on the right there a scene
15488
11:19:16,020 --> 11:19:17,020
that it's coming from a routable IP
15489
11:19:18,120 --> 11:19:19,120
address
15490
11:19:19,320 --> 11:19:20,320
it just wouldn't get routed by your um
15491
11:19:21,596 --> 11:19:22,596
ISP otherwise
15492
11:19:23,460 --> 11:19:24,460
you can tunnel addresses but you still
15493
11:19:25,916 --> 11:19:26,916
need to Tunnel them inside a routable
15494
11:19:27,360 --> 11:19:28,360
packet
15495
11:19:28,916 --> 11:19:29,916
Source Network address translation a bit
15496
11:19:31,320 --> 11:19:32,320
of a strange term this but comps here
15497
11:19:33,000 --> 11:19:34,000
are coining it
15498
11:19:34,620 --> 11:19:35,620
basically it means the um Source on the
15499
11:19:38,040 --> 11:19:39,040
inside of your network is being nattted
15500
11:19:39,960 --> 11:19:40,960
out to a routable address so you're
15501
11:19:42,360 --> 11:19:43,360
initiating the connection from your
15502
11:19:44,936 --> 11:19:45,936
source
15503
11:19:46,436 --> 11:19:47,436
so you've got a 192 Network and it's
15504
11:19:48,776 --> 11:19:49,776
been translated to a range of addresses
15505
11:19:51,660 --> 11:19:52,660
on this router probably not a good idea
15506
11:19:53,640 --> 11:19:54,640
to have one routable address because you
15507
11:19:55,320 --> 11:19:56,320
can only ever have
15508
11:19:57,300 --> 11:19:58,300
uh one connection live from the inside
15509
11:20:00,180 --> 11:20:01,180
to the outside
15510
11:20:03,000 --> 11:20:04,000
so I've covered that and since the
15511
11:20:05,276 --> 11:20:06,276
source private IP address is replaced
15512
11:20:07,080 --> 11:20:08,080
with an external public address it's
15513
11:20:09,840 --> 11:20:10,840
called sourcenat
15514
11:20:11,520 --> 11:20:12,520
to be honest I've only heard um the term
15515
11:20:13,980 --> 11:20:14,980
that's used in all my years on
15516
11:20:16,020 --> 11:20:17,020
networking but you need to be familiar
15517
11:20:18,060 --> 11:20:19,060
with this because they've put it in the
15518
11:20:19,320 --> 11:20:20,320
syllabus for some reason
15519
11:20:23,580 --> 11:20:24,580
okay so I've covered this the other
15520
11:20:25,740 --> 11:20:26,740
thing is destination Nat this is where
15521
11:20:28,916 --> 11:20:29,916
the connection has been initiated from
15522
11:20:31,620 --> 11:20:32,620
outside the network
15523
11:20:33,416 --> 11:20:34,416
and say you've got some sort of internal
15524
11:20:37,740 --> 11:20:38,740
um web server that serves members of the
15525
11:20:40,256 --> 11:20:41,256
public who want to find out more about
15526
11:20:41,820 --> 11:20:42,820
your company you normally have this off
15527
11:20:43,860 --> 11:20:44,860
a DMZ on a router interface also or a
15528
11:20:48,416 --> 11:20:49,416
firewall somewhere so this time the
15529
11:20:50,520 --> 11:20:51,520
packet has come from and the in the
15530
11:20:52,740 --> 11:20:53,740
internet
15531
11:20:53,880 --> 11:20:54,880
and it's hitting your router and your
15532
11:20:56,520 --> 11:20:57,520
router has a map in so this will be a
15533
11:20:58,860 --> 11:20:59,860
permanently permanently featured address
15534
11:21:02,756 --> 11:21:03,756
um a mapping inside your router or
15535
11:21:04,860 --> 11:21:05,860
firewall
15536
11:21:07,340 --> 11:21:08,340
now if you look at this image it's
15537
11:21:09,960 --> 11:21:10,960
probably would make more sense just to
15538
11:21:12,660 --> 11:21:13,660
have a routable address anyway on the
15539
11:21:15,180 --> 11:21:16,180
inside of your
15540
11:21:17,096 --> 11:21:18,096
um Network somewhere in the DMZ
15541
11:21:20,040 --> 11:21:21,040
the demilitarized zone which is a safe
15542
11:21:22,320 --> 11:21:23,320
zone for
15543
11:21:23,700 --> 11:21:24,700
external hosts to access that isn't on
15544
11:21:28,740 --> 11:21:29,740
the same interface as your local area
15545
11:21:30,776 --> 11:21:31,776
network that would probably be a better
15546
11:21:32,756 --> 11:21:33,756
idea but otherwise this destination that
15547
11:21:36,000 --> 11:21:37,000
is an option here
15548
11:21:38,700 --> 11:21:39,700
so I've mentioned dmz's
15549
11:21:42,240 --> 11:21:43,240
uh through our public facing server
15550
11:21:44,700 --> 11:21:45,700
Although our public facing server has an
15551
11:21:47,160 --> 11:21:48,160
internal IP address the users on the
15552
11:21:49,080 --> 11:21:50,080
internet obviously cannot connect to it
15553
11:21:50,820 --> 11:21:51,820
which we've already covered so dnat to
15554
11:21:53,880 --> 11:21:54,880
destination that is the solution there
15555
11:21:56,700 --> 11:21:57,700
you can use destination app for load
15556
11:21:58,680 --> 11:21:59,680
balancing
15557
11:21:59,880 --> 11:22:00,880
um the traffic coming to servers from
15558
11:22:01,740 --> 11:22:02,740
the internet so you could have three
15559
11:22:03,660 --> 11:22:04,660
servers low balancing
15560
11:22:05,700 --> 11:22:06,700
um lots of web connections coming in and
15561
11:22:07,980 --> 11:22:08,980
there's different types of device you
15562
11:22:09,776 --> 11:22:10,776
can actually use for this
15563
11:22:12,120 --> 11:22:13,120
um and so it's all getting load balanced
15564
11:22:13,740 --> 11:22:14,740
to one routerable IP address but then
15565
11:22:16,500 --> 11:22:17,500
two three four or more and non-routable
15566
11:22:19,620 --> 11:22:20,620
addresses on the inside of your network
15567
11:22:24,240 --> 11:22:25,240
so when the user sends a packet it
15568
11:22:26,640 --> 11:22:27,640
changes the destination public IP
15569
11:22:29,040 --> 11:22:30,040
address and to one of the internal
15570
11:22:31,436 --> 11:22:32,436
private IP addresses
15571
11:22:34,080 --> 11:22:35,080
the last thing is Pat which is actually
15572
11:22:36,060 --> 11:22:37,060
used more often than that
15573
11:22:38,820 --> 11:22:39,820
port address translation normally when
15574
11:22:41,400 --> 11:22:42,400
you have a small company you'll be
15575
11:22:43,860 --> 11:22:44,860
allocated a single IP address but you
15576
11:22:46,500 --> 11:22:47,500
still want to do nothing so what this
15577
11:22:48,776 --> 11:22:49,776
does is it uses your oneop address but
15578
11:22:51,060 --> 11:22:52,060
uses port numbers after the IP address
15579
11:22:53,880 --> 11:22:54,880
for source and destination
15580
11:22:57,240 --> 11:22:58,240
so this is the this is the solution
15581
11:23:00,180 --> 11:23:01,180
normally
15582
11:23:02,096 --> 11:23:03,096
um for this solution here you'd have a
15583
11:23:05,040 --> 11:23:06,040
static IP address in one to one but you
15584
11:23:08,580 --> 11:23:09,580
can't afford that for whatever reason so
15585
11:23:10,080 --> 11:23:11,080
you've just got one IP address
15586
11:23:11,640 --> 11:23:12,640
externally but several hosts on the
15587
11:23:13,620 --> 11:23:14,620
inside
15588
11:23:16,020 --> 11:23:17,020
so what we have is a port number for
15589
11:23:19,140 --> 11:23:20,140
example 192 168 1.3 and then a port
15590
11:23:22,740 --> 11:23:23,740
number your connection would go out
15591
11:23:26,460 --> 11:23:27,460
on a specific port number for example
15592
11:23:29,640 --> 11:23:30,640
Port 80 if you were doing a web
15593
11:23:31,200 --> 11:23:32,200
connection but it would come back in and
15594
11:23:33,840 --> 11:23:34,840
then get changed to a a random port
15595
11:23:37,200 --> 11:23:38,200
number or you can configure a range of
15596
11:23:39,776 --> 11:23:40,776
usable port numbers that are outside the
15597
11:23:42,776 --> 11:23:43,776
well-known port numbers of m0 to 10 23 I
15598
11:23:47,520 --> 11:23:48,520
think it is
15599
11:23:51,776 --> 11:23:52,776
when the internal host of the private IP
15600
11:23:53,640 --> 11:23:54,640
address initiates the session it will
15601
11:23:55,320 --> 11:23:56,320
generate a TCP or UDP port and that's
15602
11:23:58,080 --> 11:23:59,080
just unique to that session so you can
15603
11:24:00,060 --> 11:24:01,060
see here internally we've got Port
15604
11:24:03,020 --> 11:24:04,020
15345 externally two zero two zero one
15605
11:24:06,960 --> 11:24:07,960
to be honest it would normally be a
15606
11:24:09,360 --> 11:24:10,360
well-known port number such as a FTP DNS
15607
11:24:12,960 --> 11:24:13,960
or web traffic
15608
11:24:16,860 --> 11:24:17,860
yeah
15609
11:24:18,240 --> 11:24:19,240
this port um mapping is kept on a table
15610
11:24:21,000 --> 11:24:22,000
inside the router it does expire after a
15611
11:24:23,700 --> 11:24:24,700
while just to clear the table but
15612
11:24:26,040 --> 11:24:27,040
normally
15613
11:24:27,120 --> 11:24:28,120
um more than enough time for you to
15614
11:24:28,320 --> 11:24:29,320
complete all of your sessions but that
15615
11:24:30,300 --> 11:24:31,300
end table expiration time can be altered
15616
11:24:33,480 --> 11:24:34,480
on the router
15617
11:24:37,140 --> 11:24:38,140
all right so now at ipv4 IPv6 which is a
15618
11:24:41,820 --> 11:24:42,820
solution to address to depletion but we
15619
11:24:44,276 --> 11:24:45,276
don't really use that much at all with
15620
11:24:47,096 --> 11:24:48,096
IPv6 some of the advantages remember
15621
11:24:50,340 --> 11:24:51,340
security and also you get to use lots of
15622
11:24:53,040 --> 11:24:54,040
addresses on the inside of your network
15623
11:24:54,500 --> 11:24:55,500
and and up and and one address or more
15624
11:24:57,960 --> 11:24:58,960
on the outside of your network
15625
11:25:00,480 --> 11:25:01,480
all right so that's all for now thanks
15626
11:25:02,580 --> 11:25:03,580
for watching
15627
11:25:08,360 --> 11:25:09,360
[Music]
15628
11:25:28,460 --> 11:25:29,460
tcpip
15629
11:25:30,200 --> 11:25:31,200
tcpip simple services
15630
11:25:33,840 --> 11:25:34,840
in the previous module and lesson we
15631
11:25:36,480 --> 11:25:37,480
discussed the way that IP addresses are
15632
11:25:39,120 --> 11:25:40,120
assigned now in this next lesson we're
15633
11:25:41,936 --> 11:25:42,936
going to be talking more about the tcpip
15634
11:25:44,936 --> 11:25:45,936
suite and specifically in this module I
15635
11:25:48,776 --> 11:25:49,776
want to discuss some of the simple
15636
11:25:50,820 --> 11:25:51,820
services that are in the tcpip suite
15637
11:25:55,140 --> 11:25:56,140
what they do and what some of the output
15638
11:25:58,740 --> 11:25:59,740
might look like for some of the services
15639
11:26:00,776 --> 11:26:01,776
and why we might not see output for some
15640
11:26:03,060 --> 11:26:04,060
of the other services
15641
11:26:04,740 --> 11:26:05,740
now you might see this on the exam and
15642
11:26:06,776 --> 11:26:07,776
you might not but either way it's a good
15643
11:26:09,900 --> 11:26:10,900
thing to know about and just in case
15644
11:26:12,900 --> 11:26:13,900
now first we're going to talk about all
15645
11:26:16,020 --> 11:26:17,020
of these different simple tcpip services
15646
11:26:18,300 --> 11:26:19,300
and in some cases we're going to
15647
11:26:20,220 --> 11:26:21,220
demonstrate them and just to give you an
15648
11:26:22,320 --> 11:26:23,320
overview of what these are these are
15649
11:26:24,120 --> 11:26:25,120
cargen or charge in or character
15650
11:26:26,936 --> 11:26:27,936
generation
15651
11:26:28,916 --> 11:26:29,916
the daytime service
15652
11:26:31,080 --> 11:26:32,080
the discard service
15653
11:26:33,540 --> 11:26:34,540
the echo service and quote of the day
15654
11:26:36,416 --> 11:26:37,416
service now some of these happen in the
15655
11:26:38,700 --> 11:26:39,700
background are sort of embedded into
15656
11:26:40,380 --> 11:26:41,380
other protocols and services that we
15657
11:26:43,436 --> 11:26:44,436
might have seen but these are important
15658
11:26:45,120 --> 11:26:46,120
again to know about in a sort of General
15659
11:26:47,276 --> 11:26:48,276
way
15660
11:26:48,480 --> 11:26:49,480
so
15661
11:26:50,416 --> 11:26:51,416
the five uh simple tcpip services are
15662
11:26:54,960 --> 11:26:55,960
listed here along with the description
15663
11:26:57,000 --> 11:26:58,000
of what it is they do
15664
11:26:59,640 --> 11:27:00,640
cargan or character generation or charge
15665
11:27:03,000 --> 11:27:04,000
n or whatever the uh preferred way that
15666
11:27:06,840 --> 11:27:07,840
you want to pronounce it is is
15667
11:27:08,160 --> 11:27:09,160
essentially what you get anytime you
15668
11:27:10,500 --> 11:27:11,500
choose the option send test page to a
15669
11:27:14,096 --> 11:27:15,096
printer it's made up of ASCII characters
15670
11:27:16,740 --> 11:27:17,740
and ASCII again stands for the American
15671
11:27:20,300 --> 11:27:21,300
Standard code
15672
11:27:23,820 --> 11:27:24,820
for information
15673
11:27:25,520 --> 11:27:26,520
interchange so this is usually used as a
15674
11:27:29,060 --> 11:27:30,060
debugging tool when you're uh creating
15675
11:27:32,580 --> 11:27:33,580
or troubleshooting printers or print
15676
11:27:34,616 --> 11:27:35,616
test pages and so what it does it
15677
11:27:36,840 --> 11:27:37,840
literally just generates characters and
15678
11:27:40,560 --> 11:27:41,560
we'll look at this in a little bit the
15679
11:27:42,596 --> 11:27:43,596
next one is the daytime service that ATM
15680
11:27:45,180 --> 11:27:46,180
service is usually used for checking
15681
11:27:46,740 --> 11:27:47,740
errors or changes that happen within a
15682
11:27:49,740 --> 11:27:50,740
system's internal clock it presents a
15683
11:27:52,680 --> 11:27:53,680
message with the exact time that a
15684
11:27:54,776 --> 11:27:55,776
change was made or an error occurred and
15685
11:27:57,776 --> 11:27:58,776
we'll look at this format in just a
15686
11:28:00,660 --> 11:28:01,660
minute but basically what's important
15687
11:28:02,700 --> 11:28:03,700
here is that the output from this can be
15688
11:28:04,680 --> 11:28:05,680
used for for instance the Event Viewer
15689
11:28:07,436 --> 11:28:08,436
sort of what provides information to
15690
11:28:09,776 --> 11:28:10,776
that and if we're going to see it in a
15691
11:28:12,596 --> 11:28:13,596
um text based mode you will see exactly
15692
11:28:15,360 --> 11:28:16,360
what that's going to present in the next
15693
11:28:16,860 --> 11:28:17,860
slide now the discard service so we've
15694
11:28:20,040 --> 11:28:21,040
talked about
15695
11:28:21,116 --> 11:28:22,116
character generator and daytime the
15696
11:28:23,936 --> 11:28:24,936
discard service is basically used for
15697
11:28:26,460 --> 11:28:27,460
messages and information that are not
15698
11:28:28,256 --> 11:28:29,256
important and therefore should be
15699
11:28:30,000 --> 11:28:31,000
disposed of it discards these messages
15700
11:28:32,960 --> 11:28:33,960
automatically when they enter this port
15701
11:28:36,116 --> 11:28:37,116
or the port that discard is working off
15702
11:28:38,160 --> 11:28:39,160
of this can be useful when you're
15703
11:28:39,840 --> 11:28:40,840
configuring a system and using test
15704
11:28:41,580 --> 11:28:42,580
messages that you don't want necessarily
15705
11:28:43,616 --> 11:28:44,616
to display
15706
11:28:44,880 --> 11:28:45,880
so note that because the messages are
15707
11:28:47,400 --> 11:28:48,400
immediately discarded there's really no
15708
11:28:49,820 --> 11:28:50,820
response message that's issued and
15709
11:28:52,380 --> 11:28:53,380
therefore I can't show you an example of
15710
11:28:54,416 --> 11:28:55,416
one but just realize that discard is
15711
11:28:57,360 --> 11:28:58,360
going to usually be used for network
15712
11:28:59,340 --> 11:29:00,340
setup and configuration
15713
11:29:02,400 --> 11:29:03,400
and is going to make sure there is no
15714
11:29:04,740 --> 11:29:05,740
response or acknowledgment
15715
11:29:08,220 --> 11:29:09,220
now echo or the echo service sends an
15716
11:29:11,700 --> 11:29:12,700
exact copy or an echo hence the name of
15717
11:29:15,776 --> 11:29:16,776
any message that enters its port to a
15718
11:29:18,900 --> 11:29:19,900
place in the system where the message
15719
11:29:20,520 --> 11:29:21,520
can be monitored so this is often useful
15720
11:29:22,860 --> 11:29:23,860
for when you're monitoring things that
15721
11:29:25,080 --> 11:29:26,080
are going on in a network because the
15722
11:29:27,480 --> 11:29:28,480
echo service simply Echoes and copies
15723
11:29:30,416 --> 11:29:31,416
and forwards any messages it receives
15724
11:29:32,276 --> 11:29:33,276
there's really no way to show what an
15725
11:29:34,140 --> 11:29:35,140
example would look like because they
15726
11:29:36,060 --> 11:29:37,060
each look very different from each other
15727
11:29:37,560 --> 11:29:38,560
but basically in many cases we're going
15728
11:29:40,320 --> 11:29:41,320
to get some sort of message that happens
15729
11:29:41,936 --> 11:29:42,936
internally and we want the computer to
15730
11:29:44,936 --> 11:29:45,936
tell us that message once again so we
15731
11:29:47,096 --> 11:29:48,096
can see what's going on internally and
15732
11:29:49,140 --> 11:29:50,140
that's when we're going to use the echo
15733
11:29:50,520 --> 11:29:51,520
service finally the quote or the quote
15734
11:29:52,860 --> 11:29:53,860
of the day service sends a short message
15735
11:29:55,616 --> 11:29:56,616
that's been selected by the
15736
11:29:57,240 --> 11:29:58,240
administrator of the system to a
15737
11:30:00,000 --> 11:30:01,000
client's device now this service is used
15738
11:30:03,000 --> 11:30:04,000
primarily for checking the connection to
15739
11:30:05,400 --> 11:30:06,400
client devices so it's really similar to
15740
11:30:08,640 --> 11:30:09,640
like Echo the content of the message is
15741
11:30:10,916 --> 11:30:11,916
not this is not what's important what's
15742
11:30:12,840 --> 11:30:13,840
important is that
15743
11:30:14,700 --> 11:30:15,700
it is sending something and that way we
15744
11:30:17,756 --> 11:30:18,756
can make sure that the service is
15745
11:30:20,756 --> 11:30:21,756
working and that the um
15746
11:30:24,020 --> 11:30:25,020
troubleshooting is sort of easily
15747
11:30:27,416 --> 11:30:28,416
solved now as it mentions here it can be
15748
11:30:30,480 --> 11:30:31,480
taken from a specific file
15749
11:30:33,960 --> 11:30:34,960
right in here which is where random
15750
11:30:36,360 --> 11:30:37,360
quotes can be taken of if you remember
15751
11:30:38,276 --> 11:30:39,276
or if you know the hosts file it is also
15752
11:30:41,400 --> 11:30:42,400
located
15753
11:30:42,720 --> 11:30:43,720
in this folder
15754
11:30:46,020 --> 11:30:47,020
so let's take a look at this character
15755
11:30:48,660 --> 11:30:49,660
generator uh and some output that it
15756
11:30:50,936 --> 11:30:51,936
might give you
15757
11:30:54,720 --> 11:30:55,720
now this is what a test code page would
15758
11:30:58,200 --> 11:30:59,200
look like these characters are used uh
15759
11:31:01,680 --> 11:31:02,680
and they are the 95 printable ASCII
15760
11:31:05,460 --> 11:31:06,460
characters as you can see
15761
11:31:08,220 --> 11:31:09,220
from here and basically What's Happening
15762
11:31:10,980 --> 11:31:11,980
Here is that when I uh for instance and
15763
11:31:13,980 --> 11:31:14,980
this is someone going into telnet so
15764
11:31:15,720 --> 11:31:16,720
they've talented in
15765
11:31:17,096 --> 11:31:18,096
they have connected and now I've told it
15766
11:31:19,980 --> 11:31:20,980
basically to create some characters and
15767
11:31:22,616 --> 11:31:23,616
that's what it's doing here and it's
15768
11:31:24,360 --> 11:31:25,360
using all the characters that are
15769
11:31:26,220 --> 11:31:27,220
available to it in ASCII
15770
11:31:30,776 --> 11:31:31,776
and you would usually use this when
15771
11:31:32,096 --> 11:31:33,096
you're setting up a printer testing a
15772
11:31:34,020 --> 11:31:35,020
connection to a device or printer it
15773
11:31:36,960 --> 11:31:37,960
doesn't really have much of a function
15774
11:31:38,160 --> 11:31:39,160
otherwise you can see that the content
15775
11:31:40,380 --> 11:31:41,380
is not very important but all it's doing
15776
11:31:42,480 --> 11:31:43,480
is basically creating characters or
15777
11:31:44,936 --> 11:31:45,936
content for us to test with
15778
11:31:47,520 --> 11:31:48,520
the next one is the daytime service
15779
11:31:50,340 --> 11:31:51,340
report and this is what it looks like
15780
11:31:52,140 --> 11:31:53,140
and you can see that it's presented in
15781
11:31:54,360 --> 11:31:55,360
the following order it's going to show
15782
11:31:55,916 --> 11:31:56,916
us the day of the week
15783
11:31:57,660 --> 11:31:58,660
the months
15784
11:31:59,276 --> 11:32:00,276
the day
15785
11:32:01,020 --> 11:32:02,020
the year
15786
11:32:03,240 --> 11:32:04,240
the hours minutes and seconds in that
15787
11:32:06,480 --> 11:32:07,480
format and finally and very importantly
15788
11:32:09,060 --> 11:32:10,060
the time zone the reason the time zone
15789
11:32:10,740 --> 11:32:11,740
is important is let's say that we're
15790
11:32:12,416 --> 11:32:13,416
looking at this daytime in an email and
15791
11:32:14,400 --> 11:32:15,400
sometimes the headers are going to use
15792
11:32:15,776 --> 11:32:16,776
this same format all right that's
15793
11:32:18,180 --> 11:32:19,180
provided by the daytime service and
15794
11:32:20,700 --> 11:32:21,700
tcpap well I can see that oh yeah it was
15795
11:32:23,820 --> 11:32:24,820
sent
15796
11:32:25,020 --> 11:32:26,020
at 1845 which that's military time so
15797
11:32:28,616 --> 11:32:29,616
this would be 6 45 PM in sort of our
15798
11:32:32,700 --> 11:32:33,700
lingo but by knowing the time zone I can
15799
11:32:37,080 --> 11:32:38,080
actually determine where in the world it
15800
11:32:38,400 --> 11:32:39,400
was sent from and therefore for instance
15801
11:32:40,080 --> 11:32:41,080
this was sent on Pacific Standard time
15802
11:32:42,720 --> 11:32:43,720
which is in the U.S then uh I would know
15803
11:32:46,680 --> 11:32:47,680
that this is three hours later or 9 45
15804
11:32:49,500 --> 11:32:50,500
in the Eastern Time Zone
15805
11:32:53,820 --> 11:32:54,820
now none of the other uh as we've
15806
11:32:56,340 --> 11:32:57,340
mentioned none of the other uh Services
15807
11:32:58,560 --> 11:32:59,560
have any sort of output I can show you
15808
11:33:01,140 --> 11:33:02,140
but just to recap
15809
11:33:03,776 --> 11:33:04,776
what we've talked about we described and
15810
11:33:05,820 --> 11:33:06,820
demonstrated really briefly the TCP
15811
11:33:07,980 --> 11:33:08,980
simple services and these again include
15812
11:33:10,380 --> 11:33:11,380
a character generator we're really going
15813
11:33:12,240 --> 11:33:13,240
to see this a lot when we're dealing
15814
11:33:13,740 --> 11:33:14,740
with printers it's just generating
15815
11:33:16,256 --> 11:33:17,256
ASCII code
15816
11:33:18,360 --> 11:33:19,360
we looked at the daytime service which
15817
11:33:20,880 --> 11:33:21,880
is presenting the day
15818
11:33:23,340 --> 11:33:24,340
the time and also don't forget the time
15819
11:33:27,116 --> 11:33:28,116
zone which is really important
15820
11:33:30,360 --> 11:33:31,360
we looked at the discard service which
15821
11:33:32,096 --> 11:33:33,096
automatically deletes
15822
11:33:35,220 --> 11:33:36,220
messages that we don't need and so
15823
11:33:37,256 --> 11:33:38,256
there's really nothing there
15824
11:33:38,820 --> 11:33:39,820
Echo simply repeats
15825
11:33:42,416 --> 11:33:43,416
or Echoes any services or a message that
15826
11:33:46,320 --> 11:33:47,320
are happening internally and finally the
15827
11:33:48,900 --> 11:33:49,900
quote of the day takes a random quote
15828
11:33:51,300 --> 11:33:52,300
selected by the administrator or taken
15829
11:33:53,460 --> 11:33:54,460
out of a etc folder in the system 32
15830
11:33:56,180 --> 11:33:57,180
quotes area so that would be if we had
15831
11:34:00,060 --> 11:34:01,060
the root
15832
11:34:05,096 --> 11:34:06,096
which would be like system 32
15833
11:34:12,000 --> 11:34:13,000
and then Etc and then quotes that's
15834
11:34:14,400 --> 11:34:15,400
where it's going to draw something from
15835
11:34:15,660 --> 11:34:16,660
and again this is also used for
15836
11:34:18,060 --> 11:34:19,060
troubleshooting purposes
15837
11:34:21,000 --> 11:34:22,000
I showed you examples of these two
15838
11:34:22,800 --> 11:34:23,800
because they're the only ones that have
15839
11:34:24,000 --> 11:34:25,000
their own format all of the others the
15840
11:34:26,040 --> 11:34:27,040
form is not as important all it does is
15841
11:34:28,320 --> 11:34:29,320
take other information sort of
15842
11:34:30,240 --> 11:34:31,240
regurgitate it
15843
11:34:34,436 --> 11:34:35,436
now in the next module we're going to
15844
11:34:36,000 --> 11:34:37,000
take a step further and talk more about
15845
11:34:37,616 --> 11:34:38,616
some of the tcpi tools and commands and
15846
11:34:41,340 --> 11:34:42,340
get into the operating system when we do
15847
11:34:43,080 --> 11:34:44,080
so
15848
11:34:47,600 --> 11:34:48,600
[Music]
15849
11:34:56,240 --> 11:34:57,240
thank you
15850
11:35:11,660 --> 11:35:12,660
tcpip
15851
11:35:13,276 --> 11:35:14,276
tcpip tools and commands
15852
11:35:16,800 --> 11:35:17,800
so in the last module we talked about
15853
11:35:18,720 --> 11:35:19,720
the simple services that tcpip provides
15854
11:35:21,720 --> 11:35:22,720
and those you may or may not see on the
15855
11:35:24,540 --> 11:35:25,540
network plus exam
15856
11:35:27,416 --> 11:35:28,416
however in this module we're going to
15857
11:35:29,096 --> 11:35:30,096
talk about some of the most essential
15858
11:35:30,720 --> 11:35:31,720
tools when it comes to the tcpip suite
15859
11:35:34,436 --> 11:35:35,436
and I can almost guarantee you you're
15860
11:35:36,480 --> 11:35:37,480
going to see these on the exam so we're
15861
11:35:39,416 --> 11:35:40,416
first going to discuss and demonstrate
15862
11:35:41,400 --> 11:35:42,400
all of the tcpip tools and some of these
15863
11:35:45,060 --> 11:35:46,060
tools include the Ping command and some
15864
11:35:47,580 --> 11:35:48,580
of these we might have seen previously
15865
11:35:48,840 --> 11:35:49,840
as well perhaps an A-Plus and some of
15866
11:35:51,596 --> 11:35:52,596
these also I'll go into the operating
15867
11:35:53,096 --> 11:35:54,096
system and show you so we're going to
15868
11:35:55,380 --> 11:35:56,380
see the Ping command which basically
15869
11:35:57,960 --> 11:35:58,960
tests
15870
11:36:00,616 --> 11:36:01,616
for connectivity
15871
11:36:05,460 --> 11:36:06,460
we're also going to look at the trace
15872
11:36:07,256 --> 11:36:08,256
route command which basically traces a
15873
11:36:12,480 --> 11:36:13,480
ping
15874
11:36:13,380 --> 11:36:14,380
route
15875
11:36:14,580 --> 11:36:15,580
and remember when we were talking about
15876
11:36:17,756 --> 11:36:18,756
um uh protocols previously we mentioned
15877
11:36:21,596 --> 11:36:22,596
the icmp protocol
15878
11:36:24,116 --> 11:36:25,116
the control messaging protocol and that
15879
11:36:27,180 --> 11:36:28,180
is what a ping and a trace route command
15880
11:36:29,756 --> 11:36:30,756
use or these types of packets
15881
11:36:32,520 --> 11:36:33,520
so we're also going to look at a
15882
11:36:34,020 --> 11:36:35,020
protocol analyzer not necessarily a
15883
11:36:37,740 --> 11:36:38,740
command line tool but something that
15884
11:36:39,480 --> 11:36:40,480
allows us to analyze the protocols uh or
15885
11:36:44,400 --> 11:36:45,400
rather the packets that are going in and
15886
11:36:46,140 --> 11:36:47,140
out of a
15887
11:36:48,380 --> 11:36:49,380
network or system
15888
11:36:50,820 --> 11:36:51,820
we'll get a port scanner sort of does
15889
11:36:52,740 --> 11:36:53,740
the same thing we'll talk about the
15890
11:36:54,180 --> 11:36:55,180
difference between these two
15891
11:36:56,160 --> 11:36:57,160
we'll also get something called nslookup
15892
11:36:57,960 --> 11:36:58,960
and
15893
11:36:59,400 --> 11:37:00,400
NS doesn't ring a bell with you that is
15894
11:37:02,276 --> 11:37:03,276
like DNS or name server lookup
15895
11:37:07,560 --> 11:37:08,560
how we convert between an IP address
15896
11:37:13,616 --> 11:37:14,616
and a fully qualified domain name such
15897
11:37:18,116 --> 11:37:19,116
as
15898
11:37:18,960 --> 11:37:19,960
Google
15899
11:37:21,000 --> 11:37:22,000
we're also look at the ARP command which
15900
11:37:23,756 --> 11:37:24,756
allows us just like NS DNS which does a
15901
11:37:27,360 --> 11:37:28,360
name to an IP address ARP is what is
15902
11:37:29,820 --> 11:37:30,820
responsible for routing and allowed us
15903
11:37:31,860 --> 11:37:32,860
to convert between an IP address
15904
11:37:34,616 --> 11:37:35,616
and a MAC address or physical address
15905
11:37:38,340 --> 11:37:39,340
so you can see where this is really
15906
11:37:39,900 --> 11:37:40,900
going to come into uh into handy when
15907
11:37:42,900 --> 11:37:43,900
we're talking about routing and switches
15908
11:37:47,096 --> 11:37:48,096
finally we're going to look at the route
15909
11:37:49,320 --> 11:37:50,320
command which can present us with
15910
11:37:51,180 --> 11:37:52,180
routing tables
15911
11:37:53,520 --> 11:37:54,520
and it's specifically more or less used
15912
11:37:55,560 --> 11:37:56,560
when we're dealing with routers not so
15913
11:37:57,540 --> 11:37:58,540
much in Windows
15914
11:38:00,900 --> 11:38:01,900
all right so first the Ping command the
15915
11:38:03,900 --> 11:38:04,900
Ping tool in the Ping command are
15916
11:38:05,460 --> 11:38:06,460
extremely useful when it comes to
15917
11:38:07,020 --> 11:38:08,020
troubleshooting and testing connectivity
15918
11:38:09,500 --> 11:38:10,500
basically what the tool does is send a
15919
11:38:12,240 --> 11:38:13,240
packet of information in that packet
15920
11:38:14,460 --> 11:38:15,460
again is icmp
15921
11:38:17,096 --> 11:38:18,096
through a connection and waits to see if
15922
11:38:19,436 --> 11:38:20,436
it receives some packets back this is
15923
11:38:21,660 --> 11:38:22,660
not unlike when you used to see the
15924
11:38:24,416 --> 11:38:25,416
radar screens on a computer on a TV or
15925
11:38:28,140 --> 11:38:29,140
program we're talking about with um uh
15926
11:38:31,140 --> 11:38:32,140
submarines for instance and you would
15927
11:38:33,060 --> 11:38:34,060
see basically a submarine here and you'd
15928
11:38:35,276 --> 11:38:36,276
hear a ping
15929
11:38:36,660 --> 11:38:37,660
coming off of that so it gets its name
15930
11:38:39,300 --> 11:38:40,300
from that sort of sound so the data
15931
11:38:41,820 --> 11:38:42,820
literally bounces or pings right back if
15932
11:38:44,460 --> 11:38:45,460
there's an established connection
15933
11:38:46,380 --> 11:38:47,380
can be also used to test the maximum
15934
11:38:49,320 --> 11:38:50,320
transmission unit or the mtus and
15935
11:38:52,020 --> 11:38:53,020
remember we talked about that when we
15936
11:38:53,520 --> 11:38:54,520
dealt with an MTU black hole was in a
15937
11:38:57,596 --> 11:38:58,596
previous lesson this is the maximum
15938
11:39:00,000 --> 11:39:01,000
amount of data packets that can be sent
15939
11:39:02,880 --> 11:39:03,880
over a network at any one time or the
15940
11:39:05,220 --> 11:39:06,220
maximum size of that data packets so
15941
11:39:07,740 --> 11:39:08,740
using this you can test the time it
15942
11:39:09,480 --> 11:39:10,480
takes in milliseconds for data to travel
15943
11:39:12,416 --> 11:39:13,416
end to Android to other devices on the
15944
11:39:14,700 --> 11:39:15,700
network
15945
11:39:15,840 --> 11:39:16,840
this can also be done on the localhost
15946
11:39:17,880 --> 11:39:18,880
and you remember the localhost is
15947
11:39:21,080 --> 11:39:22,080
127.0.0.1 that's the IP address for it
15948
11:39:26,400 --> 11:39:27,400
and we can test this all by opening the
15949
11:39:28,436 --> 11:39:29,436
command prompt and typing in ping and
15950
11:39:32,040 --> 11:39:33,040
then the IP address
15951
11:39:34,140 --> 11:39:35,140
so let's take a look at this uh for just
15952
11:39:37,020 --> 11:39:38,020
a second
15953
11:39:40,380 --> 11:39:41,380
if we're here and we have our Command
15954
11:39:42,900 --> 11:39:43,900
Prompt and I wanted to type for instance
15955
11:39:45,116 --> 11:39:46,116
ping 127.0.0.1
15956
11:39:48,416 --> 11:39:49,416
which would be the Local Host
15957
11:39:51,060 --> 11:39:52,060
I can tell that my time is less than one
15958
11:39:54,060 --> 11:39:55,060
millisecond which makes complete sense
15959
11:39:56,040 --> 11:39:57,040
since there should be no loss of data it
15960
11:39:58,680 --> 11:39:59,680
should take no time and you can see that
15961
11:40:00,776 --> 11:40:01,776
no loss of data right here
15962
11:40:03,360 --> 11:40:04,360
right because we're sending it there and
15963
11:40:05,640 --> 11:40:06,640
back and obviously we're dealing with
15964
11:40:07,800 --> 11:40:08,800
ourselves the local host or the 127.0.01
15965
11:40:11,700 --> 11:40:12,700
so it shouldn't be an issue and if we do
15966
11:40:13,560 --> 11:40:14,560
that notice that when I use localhost
15967
11:40:15,360 --> 11:40:16,360
I'm using my own name and and it's also
15968
11:40:19,560 --> 11:40:20,560
giving the IPv6 IP address here now if I
15969
11:40:22,500 --> 11:40:23,500
clear the screen for a second I can also
15970
11:40:24,240 --> 11:40:25,240
for instance ping google.com and you'll
15971
11:40:26,880 --> 11:40:27,880
see that it actually sends first it
15972
11:40:29,276 --> 11:40:30,276
figures out what the IP address is and
15973
11:40:31,020 --> 11:40:32,020
then sends that and it gives us the time
15974
11:40:32,880 --> 11:40:33,880
that it takes
15975
11:40:34,200 --> 11:40:35,200
to get there and back it also gives us
15976
11:40:36,360 --> 11:40:37,360
some statistics for instance it was sent
15977
11:40:38,756 --> 11:40:39,756
four of them were sent for them received
15978
11:40:40,800 --> 11:40:41,800
zero lost and so we know that on average
15979
11:40:43,980 --> 11:40:44,980
this is taking 13 milliseconds to get
15980
11:40:45,960 --> 11:40:46,960
from us to Google and if you imagine
15981
11:40:48,180 --> 11:40:49,180
that this was a local host uh or rather
15982
11:40:52,080 --> 11:40:53,080
a sorry a local uh server on my network
15983
11:40:54,840 --> 11:40:55,840
and I was rebooting that server this
15984
11:40:57,416 --> 11:40:58,416
could help me tell whether the server is
15985
11:40:58,860 --> 11:40:59,860
back up again and one of the things I
15986
11:41:00,776 --> 11:41:01,776
might want to do with that and I'm just
15987
11:41:02,460 --> 11:41:03,460
going to use
15988
11:41:03,540 --> 11:41:04,540
The Local Host right now is use the
15989
11:41:06,116 --> 11:41:07,116
slash T
15990
11:41:08,580 --> 11:41:09,580
um
15991
11:41:09,360 --> 11:41:10,360
switch and what this will do is it'll
15992
11:41:11,520 --> 11:41:12,520
continually ping the same IP address
15993
11:41:14,160 --> 11:41:15,160
over and over again now I so for
15994
11:41:17,340 --> 11:41:18,340
instance if I was waiting for a server
15995
11:41:18,660 --> 11:41:19,660
to come back online this would be an
15996
11:41:20,096 --> 11:41:21,096
easy way for me to tell whether it's
15997
11:41:21,960 --> 11:41:22,960
come back online or not and I could exit
15998
11:41:25,256 --> 11:41:26,256
that by pressing Ctrl C all right
15999
11:41:28,616 --> 11:41:29,616
so the next one I want to talk about is
16000
11:41:30,240 --> 11:41:31,240
trace route which actually goes hand in
16001
11:41:32,160 --> 11:41:33,160
hand with ping because he also uses that
16002
11:41:35,416 --> 11:41:36,416
icmp data packet or
16003
11:41:38,580 --> 11:41:39,580
protocol it basically tells us the time
16004
11:41:42,060 --> 11:41:43,060
it takes for a pack to travel between
16005
11:41:44,276 --> 11:41:45,276
different routers and devices and we
16006
11:41:46,616 --> 11:41:47,616
call this the amount of hops along the
16007
11:41:49,800 --> 11:41:50,800
uh the network so not only tests where
16008
11:41:52,916 --> 11:41:53,916
connectivity might have been lost but
16009
11:41:55,320 --> 11:41:56,320
it's also going to test
16010
11:41:57,240 --> 11:41:58,240
um
16011
11:41:58,580 --> 11:41:59,580
the time that it takes to get from one
16012
11:42:01,200 --> 11:42:02,200
end to the other end of the connection
16013
11:42:02,880 --> 11:42:03,880
and it's also going to also show us the
16014
11:42:05,220 --> 11:42:06,220
number of hops
16015
11:42:06,840 --> 11:42:07,840
between those computers so for instance
16016
11:42:10,200 --> 11:42:11,200
between me and Google there might be
16017
11:42:12,240 --> 11:42:13,240
four different computers and so
16018
11:42:15,060 --> 11:42:16,060
each one of these is called a hop
16019
11:42:19,140 --> 11:42:20,140
and we can measure how far the packet is
16020
11:42:21,840 --> 11:42:22,840
traveling before it gets back to us
16021
11:42:25,140 --> 11:42:26,140
now I can also use this to test where a
16022
11:42:28,800 --> 11:42:29,800
where a downed router might be or where
16023
11:42:31,140 --> 11:42:32,140
in the connection a down to router might
16024
11:42:32,756 --> 11:42:33,756
be so if we go in here for a second and
16025
11:42:35,880 --> 11:42:36,880
let's take a look at the command prompt
16026
11:42:38,700 --> 11:42:39,700
here
16027
11:42:39,960 --> 11:42:40,960
and let's say I go to trace route
16028
11:42:43,740 --> 11:42:44,740
google.com now what's going to happen is
16029
11:42:46,500 --> 11:42:47,500
it's going to start saying all the
16030
11:42:48,900 --> 11:42:49,900
different hops going to tell me how long
16031
11:42:50,400 --> 11:42:51,400
it takes to get from one place to the
16032
11:42:52,800 --> 11:42:53,800
next and we can see also where it's so
16033
11:42:55,200 --> 11:42:56,200
right here we're still in New York let's
16034
11:42:58,200 --> 11:42:59,200
see NYC I can probably guess this is
16035
11:43:00,900 --> 11:43:01,900
some place in my ISP and now it looks
16036
11:43:03,540 --> 11:43:04,540
like it's starting to go out get further
16037
11:43:05,580 --> 11:43:06,580
out and we can see that the amount of
16038
11:43:06,840 --> 11:43:07,840
time it's taking is also more and more
16039
11:43:09,300 --> 11:43:10,300
so between getting between me and and
16040
11:43:11,880 --> 11:43:12,880
Google you can see how far we're having
16041
11:43:14,276 --> 11:43:15,276
to go until we finally get to the
16042
11:43:15,720 --> 11:43:16,720
google.com web uh server which would be
16043
11:43:19,380 --> 11:43:20,380
right here and we know it took about 10
16044
11:43:22,140 --> 11:43:23,140
hops
16045
11:43:23,880 --> 11:43:24,880
now you can see it has a maximum of 30
16046
11:43:25,740 --> 11:43:26,740
Hops and we can actually set that in the
16047
11:43:28,256 --> 11:43:29,256
switches if we need to but I wouldn't
16048
11:43:29,640 --> 11:43:30,640
worry about that for the exam
16049
11:43:32,580 --> 11:43:33,580
and just to show you what it looks like
16050
11:43:34,080 --> 11:43:35,080
if I'm tracing the Local Host you can
16051
11:43:36,776 --> 11:43:37,776
see it only takes one hop obviously
16052
11:43:38,936 --> 11:43:39,936
because or not even a hop because it's
16053
11:43:41,880 --> 11:43:42,880
myself I should be no route to get to me
16054
11:43:45,540 --> 11:43:46,540
now going away from the command line for
16055
11:43:47,400 --> 11:43:48,400
a second I want to talk about what's
16056
11:43:48,840 --> 11:43:49,840
called a protocol analyzer or a network
16057
11:43:51,000 --> 11:43:52,000
analyzer this is an essential tool when
16058
11:43:53,276 --> 11:43:54,276
you're running a network it basically
16059
11:43:54,720 --> 11:43:55,720
gives you a readable report of virtually
16060
11:43:57,416 --> 11:43:58,416
everything that's being sent and
16061
11:43:58,980 --> 11:43:59,980
transferred over your network so these
16062
11:44:01,020 --> 11:44:02,020
analyzers will capture packets that are
16063
11:44:03,720 --> 11:44:04,720
going through the network and put them
16064
11:44:05,276 --> 11:44:06,276
into a buffer zone now this buffer zone
16065
11:44:08,160 --> 11:44:09,160
just like the buffer zone we're dealing
16066
11:44:09,596 --> 11:44:10,596
with YouTube or Netflix and buffering a
16067
11:44:13,560 --> 11:44:14,560
video is going to hold on to these
16068
11:44:16,200 --> 11:44:17,200
packets and we can either capture all
16069
11:44:18,960 --> 11:44:19,960
the packets or we can capture specific
16070
11:44:21,720 --> 11:44:22,720
packets based on a filter
16071
11:44:29,096 --> 11:44:30,096
it can then provide us with an easy
16072
11:44:31,380 --> 11:44:32,380
readable overview of what is contained
16073
11:44:33,480 --> 11:44:34,480
within each packet this allows the
16074
11:44:35,756 --> 11:44:36,756
administrator total control of what does
16075
11:44:38,220 --> 11:44:39,220
and doesn't pass through the network and
16076
11:44:39,960 --> 11:44:40,960
can also stop potentially dangerous or
16077
11:44:43,256 --> 11:44:44,256
unwanted pieces of data to pass through
16078
11:44:45,720 --> 11:44:46,720
the network undetected
16079
11:44:47,700 --> 11:44:48,700
and so what you can see here is if this
16080
11:44:50,040 --> 11:44:51,040
is our cloud or our Network we're going
16081
11:44:52,256 --> 11:44:53,256
to call this a TCP Network just because
16082
11:44:53,820 --> 11:44:54,820
this is basically our our Wan and here
16083
11:44:56,936 --> 11:44:57,936
let's say I have one Lan and another
16084
11:44:59,460 --> 11:45:00,460
land I'm going to have a protocol
16085
11:45:01,740 --> 11:45:02,740
analyzer a network analyzer in between
16086
11:45:03,960 --> 11:45:04,960
my network
16087
11:45:05,960 --> 11:45:06,960
in my land that way I can analyze
16088
11:45:09,416 --> 11:45:10,416
exactly what's going on some ways this
16089
11:45:11,460 --> 11:45:12,460
might also take the form of a firewall
16090
11:45:15,000 --> 11:45:16,000
now this is different from what's called
16091
11:45:16,616 --> 11:45:17,616
a port scanner a port scanner does
16092
11:45:19,200 --> 11:45:20,200
exactly what it sounds like it basically
16093
11:45:21,540 --> 11:45:22,540
scans the network for open ports either
16094
11:45:25,020 --> 11:45:26,020
for malicious or for safety reasons so
16095
11:45:29,040 --> 11:45:30,040
it's usually used by administrators to
16096
11:45:31,200 --> 11:45:32,200
check the security of their system and
16097
11:45:33,116 --> 11:45:34,116
make sure nothing's left open oppositely
16098
11:45:34,980 --> 11:45:35,980
it can be used by attackers for their
16099
11:45:37,020 --> 11:45:38,020
advantage so uh if a poor if I'm on the
16100
11:45:40,256 --> 11:45:41,256
internal I might use a port scanner to
16101
11:45:43,436 --> 11:45:44,436
scan my firewall to see what's going to
16102
11:45:46,020 --> 11:45:47,020
be allowed through I might also put my
16103
11:45:48,480 --> 11:45:49,480
port scanner over here and have it try
16104
11:45:50,820 --> 11:45:51,820
to come in alternatively a hacker could
16105
11:45:53,460 --> 11:45:54,460
use a port scanner to go through and
16106
11:45:55,616 --> 11:45:56,616
scan for open ports if there are any
16107
11:45:58,080 --> 11:45:59,080
open ports it can then use those
16108
11:46:01,800 --> 11:46:02,800
to try to get into my system so I can
16109
11:46:04,436 --> 11:46:05,436
use it either as a white hat
16110
11:46:11,936 --> 11:46:12,936
or as a black hat
16111
11:46:13,860 --> 11:46:14,860
white hat means a good hacker black hat
16112
11:46:16,680 --> 11:46:17,680
means a bad hacker
16113
11:46:20,160 --> 11:46:21,160
now let's get back into uh our command
16114
11:46:22,616 --> 11:46:23,616
line for just a second here the name
16115
11:46:24,480 --> 11:46:25,480
server lookup or NS lookup and again
16116
11:46:26,936 --> 11:46:27,936
whenever you see NS as in DNS domain
16117
11:46:29,400 --> 11:46:30,400
name system you can think that has
16118
11:46:31,080 --> 11:46:32,080
something to do with name server or name
16119
11:46:32,700 --> 11:46:33,700
system it's used to basically find out
16120
11:46:37,220 --> 11:46:38,220
uh what the server and address
16121
11:46:39,596 --> 11:46:40,596
information is for a domain that's
16122
11:46:41,276 --> 11:46:42,276
queried it's mostly used to troubleshoot
16123
11:46:45,840 --> 11:46:46,840
domain name service related items and
16124
11:46:48,180 --> 11:46:49,180
you can also get information about a
16125
11:46:49,436 --> 11:46:50,436
systems configuration now dig actually
16126
11:46:51,900 --> 11:46:52,900
does the same thing but it's a little
16127
11:46:54,180 --> 11:46:55,180
more detailed and it only works with
16128
11:46:56,276 --> 11:46:57,276
Unix or Linux systems so here's an
16129
11:46:58,860 --> 11:46:59,860
example of what the NS lookup would look
16130
11:47:00,840 --> 11:47:01,840
like and you can see if NS look up here
16131
11:47:03,116 --> 11:47:04,116
and then what did we do well we asked it
16132
11:47:05,756 --> 11:47:06,756
for Wikipedia's name and up it pops the
16133
11:47:10,256 --> 11:47:11,256
IP address and it also tells us when
16134
11:47:12,660 --> 11:47:13,660
whether it's authoritative or
16135
11:47:14,096 --> 11:47:15,096
non-authoritative authoritative would be
16136
11:47:16,256 --> 11:47:17,256
a DNS server that's somewhere out on the
16137
11:47:18,360 --> 11:47:19,360
internet that is definitely has all the
16138
11:47:20,700 --> 11:47:21,700
information non-authoritative means it
16139
11:47:22,560 --> 11:47:23,560
might be a local one so if we were to
16140
11:47:24,596 --> 11:47:25,596
look at this for a second for ourselves
16141
11:47:27,900 --> 11:47:28,900
let's do NS lookup to go into the
16142
11:47:30,240 --> 11:47:31,240
utility
16143
11:47:31,916 --> 11:47:32,916
and now we could for instance look up uh
16144
11:47:35,340 --> 11:47:36,340
google.com
16145
11:47:38,040 --> 11:47:39,040
and it'll tell us all the different IP
16146
11:47:40,740 --> 11:47:41,740
addresses that are available for
16147
11:47:41,880 --> 11:47:42,880
google.com
16148
11:47:43,080 --> 11:47:44,080
yahoo.com
16149
11:47:44,580 --> 11:47:45,580
maybe even microsoft.com
16150
11:47:47,220 --> 11:47:48,220
CNN.com
16151
11:47:48,840 --> 11:47:49,840
etc etc so you can see all these
16152
11:47:51,240 --> 11:47:52,240
different ones that are coming through
16153
11:47:52,256 --> 11:47:53,256
now notice that CNN.com actually
16154
11:47:54,720 --> 11:47:55,720
wouldn't let us out and neither would
16155
11:47:56,276 --> 11:47:57,276
microsoft.com that's because they're
16156
11:47:58,916 --> 11:47:59,916
actually blocking the they're filtering
16157
11:48:01,616 --> 11:48:02,616
out the type of uh ports or protocols
16158
11:48:05,820 --> 11:48:06,820
that are going to be allowing uh that
16159
11:48:07,616 --> 11:48:08,616
are going to allow like the icmp Ping so
16160
11:48:10,140 --> 11:48:11,140
if we were to go out of this for a
16161
11:48:11,340 --> 11:48:12,340
second
16162
11:48:12,900 --> 11:48:13,900
and by the way you do that as Ctrl C and
16163
11:48:15,660 --> 11:48:16,660
if I tried pinging microsoft.com you'll
16164
11:48:18,416 --> 11:48:19,416
notice
16165
11:48:19,616 --> 11:48:20,616
that it actually doesn't come back and
16166
11:48:22,256 --> 11:48:23,256
that's because they're actually shutting
16167
11:48:24,300 --> 11:48:25,300
out icmp packets from going in
16168
11:48:30,240 --> 11:48:31,240
now another one related somewhat is
16169
11:48:33,000 --> 11:48:34,000
what's called ARP or address resolution
16170
11:48:35,040 --> 11:48:36,040
protocol we actually talked about this
16171
11:48:36,900 --> 11:48:37,900
previously and it's you really use to
16172
11:48:39,416 --> 11:48:40,416
find the media access control or Mac
16173
11:48:41,936 --> 11:48:42,936
address or the physical address for an
16174
11:48:45,480 --> 11:48:46,480
IP address or vice versa remember this
16175
11:48:48,596 --> 11:48:49,596
is the physical
16176
11:48:51,300 --> 11:48:52,300
address it's hardwired onto the device
16177
11:48:54,300 --> 11:48:55,300
the MAC address is the system's physical
16178
11:48:56,700 --> 11:48:57,700
address and the IP address is the one
16179
11:48:58,980 --> 11:48:59,980
again assigned by a server or manually
16180
11:49:01,256 --> 11:49:02,256
assigned in a way this would be like
16181
11:49:03,840 --> 11:49:04,840
your phone number
16182
11:49:05,520 --> 11:49:06,520
and this would be like your social
16183
11:49:07,080 --> 11:49:08,080
security number which is given to you by
16184
11:49:08,936 --> 11:49:09,936
the government
16185
11:49:10,256 --> 11:49:11,256
the way it does this is we're actually
16186
11:49:12,116 --> 11:49:13,116
going to send out Discovery packets in
16187
11:49:14,160 --> 11:49:15,160
order to find out the MAC address of a
16188
11:49:15,900 --> 11:49:16,900
destination system and once it
16189
11:49:17,700 --> 11:49:18,700
establishes that it sends that Mac
16190
11:49:19,500 --> 11:49:20,500
address to the sending or receiving
16191
11:49:21,540 --> 11:49:22,540
computer now the two computers can now
16192
11:49:23,640 --> 11:49:24,640
communicate using IP addresses because
16193
11:49:26,040 --> 11:49:27,040
they can both actually resolve to IP
16194
11:49:28,800 --> 11:49:29,800
addresses so basically I want to send
16195
11:49:31,380 --> 11:49:32,380
something
16196
11:49:32,400 --> 11:49:33,400
right so what I'm going to do is I'm
16197
11:49:33,840 --> 11:49:34,840
going to go out hit a router the router
16198
11:49:36,596 --> 11:49:37,596
uses arp in order to get the MAC address
16199
11:49:43,500 --> 11:49:44,500
to the sending computer and now we can
16200
11:49:46,020 --> 11:49:47,020
talk directly
16201
11:49:48,300 --> 11:49:49,300
because now I know what your Mac address
16202
11:49:51,240 --> 11:49:52,240
and IP address equal
16203
11:49:56,276 --> 11:49:57,276
finally
16204
11:50:00,720 --> 11:50:01,720
the route command is extremely handy and
16205
11:50:03,540 --> 11:50:04,540
can be used
16206
11:50:04,820 --> 11:50:05,820
fairly often it basically just shows you
16207
11:50:07,740 --> 11:50:08,740
the routing table which is going to give
16208
11:50:10,256 --> 11:50:11,256
you a list of all the routes network
16209
11:50:12,300 --> 11:50:13,300
connections and so on that the user has
16210
11:50:14,580 --> 11:50:15,580
the option to then edit now the reason
16211
11:50:17,160 --> 11:50:18,160
you might want to edit it is if for
16212
11:50:19,256 --> 11:50:20,256
instance in your router you want to tell
16213
11:50:22,020 --> 11:50:23,020
it to use one route instead of another
16214
11:50:24,660 --> 11:50:25,660
so an example here
16215
11:50:27,720 --> 11:50:28,720
shows us The Gateway
16216
11:50:31,560 --> 11:50:32,560
the mask
16217
11:50:35,276 --> 11:50:36,276
so draw these really quickly
16218
11:50:38,096 --> 11:50:39,096
and the interface and the sorry the
16219
11:50:40,616 --> 11:50:41,616
metric
16220
11:50:42,300 --> 11:50:43,300
as well as the interface and these are
16221
11:50:44,040 --> 11:50:45,040
all numbers so these might not mean a
16222
11:50:46,320 --> 11:50:47,320
lot to you but if you had a guide and
16223
11:50:48,000 --> 11:50:49,000
you knew where they were going if you
16224
11:50:49,200 --> 11:50:50,200
knew what your interface was for
16225
11:50:50,700 --> 11:50:51,700
instance is it a wireless internet base
16226
11:50:52,256 --> 11:50:53,256
or was it a your wired interface that
16227
11:50:55,140 --> 11:50:56,140
would prescribe a specific number
16228
11:50:57,660 --> 11:50:58,660
the Gateway is going to say what Gateway
16229
11:50:59,276 --> 11:51:00,276
you need to get out and the subnet mask
16230
11:51:01,740 --> 11:51:02,740
and you could actually add
16231
11:51:05,880 --> 11:51:06,880
specific information to this to create
16232
11:51:09,180 --> 11:51:10,180
your own routing table and this you
16233
11:51:11,160 --> 11:51:12,160
would do really not so much on your
16234
11:51:12,776 --> 11:51:13,776
computer but more if you're working on a
16235
11:51:14,640 --> 11:51:15,640
router say Cisco router so you can do
16236
11:51:17,400 --> 11:51:18,400
to tell it exactly where you want
16237
11:51:19,140 --> 11:51:20,140
information to be routed
16238
11:51:23,340 --> 11:51:24,340
so just to recap we discussed and
16239
11:51:25,916 --> 11:51:26,916
demonstrated several TCP tools including
16240
11:51:28,860 --> 11:51:29,860
ping which we're really going to use to
16241
11:51:32,160 --> 11:51:33,160
test connectivity
16242
11:51:34,200 --> 11:51:35,200
and remember you want to hold on to the
16243
11:51:37,800 --> 11:51:38,800
Slash
16244
11:51:38,880 --> 11:51:39,880
t-switch which is going to do it
16245
11:51:41,520 --> 11:51:42,520
indefinitely trace route which is going
16246
11:51:44,040 --> 11:51:45,040
to measure the Hops and can also tell
16247
11:51:46,680 --> 11:51:47,680
you where
16248
11:51:50,160 --> 11:51:51,160
uh connection has been lost a protocol
16249
11:51:53,520 --> 11:51:54,520
analyzer which is going to look at or
16250
11:51:55,380 --> 11:51:56,380
network protocol analyzer we're going to
16251
11:51:57,360 --> 11:51:58,360
look at all the protocols coming in and
16252
11:51:58,860 --> 11:51:59,860
can actually filter them in or out a
16253
11:52:01,436 --> 11:52:02,436
port scanner which can be used to show
16254
11:52:03,776 --> 11:52:04,776
open ports either as a security
16255
11:52:06,720 --> 11:52:07,720
precaution or if I'm trying to
16256
11:52:08,756 --> 11:52:09,756
infiltrate your network the NS lookup
16257
11:52:12,480 --> 11:52:13,480
which is that name server could also be
16258
11:52:14,820 --> 11:52:15,820
dig by the way which is on Unix systems
16259
11:52:18,480 --> 11:52:19,480
and this is going to allow me to get my
16260
11:52:20,276 --> 11:52:21,276
IP address to a fully qualified domain
16261
11:52:24,180 --> 11:52:25,180
name
16262
11:52:25,320 --> 11:52:26,320
ARP address resolution protocol which is
16263
11:52:28,800 --> 11:52:29,800
specifically going from IP address to
16264
11:52:30,960 --> 11:52:31,960
MAC address it sort of really allows
16265
11:52:33,180 --> 11:52:34,180
routing to occur this is really a
16266
11:52:35,580 --> 11:52:36,580
principle in routers
16267
11:52:38,096 --> 11:52:39,096
and finally the route command which
16268
11:52:41,160 --> 11:52:42,160
allows us to edit the routing tables and
16269
11:52:44,640 --> 11:52:45,640
would be really useful if I was using
16270
11:52:47,220 --> 11:52:48,220
one of my servers as a router you're not
16271
11:52:50,096 --> 11:52:51,096
really going to see routing a route
16272
11:52:51,776 --> 11:52:52,776
command on the network plus exam but I
16273
11:52:55,256 --> 11:52:56,256
guarantee you'll see all these others
16274
11:52:57,300 --> 11:52:58,300
mentioned
16275
11:53:00,000 --> 11:53:01,000
so uh now that we've finished up this
16276
11:53:01,980 --> 11:53:02,980
very brief lesson on TCP the tools and
16277
11:53:04,980 --> 11:53:05,980
the simple Services we're going to go
16278
11:53:06,660 --> 11:53:07,660
into Lan Administration and
16279
11:53:09,000 --> 11:53:10,000
implementation a bit more in depth
16280
11:53:15,190 --> 11:53:16,190
[Music]
16281
11:53:19,276 --> 11:53:20,276
thank you
16282
11:53:22,916 --> 11:53:23,916
foreign
16283
11:53:38,480 --> 11:53:39,480
Network Administration and
16284
11:53:41,160 --> 11:53:42,160
implementation
16285
11:53:42,840 --> 11:53:43,840
so in previous lessons we've discussed a
16286
11:53:45,480 --> 11:53:46,480
lot of the tools the networking
16287
11:53:47,460 --> 11:53:48,460
fundamentals the theory and so on and
16288
11:53:50,096 --> 11:53:51,096
now we're going to get into a little
16289
11:53:52,380 --> 11:53:53,380
more of the Practical side and that's in
16290
11:53:54,416 --> 11:53:55,416
creating and maintaining a local area
16291
11:53:57,116 --> 11:53:58,116
network wide area network and so on and
16292
11:53:58,800 --> 11:53:59,800
so forth this module is certainly just
16293
11:54:01,560 --> 11:54:02,560
an overview of local area network and
16294
11:54:04,256 --> 11:54:05,256
some of the best practices that go along
16295
11:54:05,820 --> 11:54:06,820
with it as we get more in depth over the
16296
11:54:07,860 --> 11:54:08,860
coming lessons and modules we'll talk
16297
11:54:10,380 --> 11:54:11,380
more about the specifics and what we
16298
11:54:12,300 --> 11:54:13,300
need to do
16299
11:54:13,256 --> 11:54:14,256
so in this module we're going to talk
16300
11:54:16,020 --> 11:54:17,020
about an overview of a lan kind of go
16301
11:54:18,360 --> 11:54:19,360
back over what it is and also
16302
11:54:21,300 --> 11:54:22,300
um when we'd probably want to use one
16303
11:54:23,580 --> 11:54:24,580
and then we're going to identify the
16304
11:54:25,500 --> 11:54:26,500
steps to setting up a lan including
16305
11:54:27,900 --> 11:54:28,900
using a network plan having backups
16306
11:54:30,720 --> 11:54:31,720
creating proper documentation auditing
16307
11:54:34,020 --> 11:54:35,020
and security
16308
11:54:36,416 --> 11:54:37,416
so first what is a lan well there are
16309
11:54:38,220 --> 11:54:39,220
two types of networks as you recall one
16310
11:54:40,320 --> 11:54:41,320
is a lan and the other is a Wan a land
16311
11:54:42,776 --> 11:54:43,776
stands for again a local area network
16312
11:54:45,360 --> 11:54:46,360
and the local area network is really any
16313
11:54:48,660 --> 11:54:49,660
sort of local or geographically
16314
11:54:52,080 --> 11:54:53,080
um
16315
11:54:52,680 --> 11:54:53,680
uh specific Network now Wan stands for a
16316
11:54:57,416 --> 11:54:58,416
wide area network and we're going to
16317
11:54:58,500 --> 11:54:59,500
talk about that in more depth in the
16318
11:55:00,000 --> 11:55:01,000
future so because Lan is restricted to
16319
11:55:02,276 --> 11:55:03,276
one geographical location such as a
16320
11:55:04,560 --> 11:55:05,560
school or a small office building it's a
16321
11:55:06,540 --> 11:55:07,540
lot easier to administer and requires a
16322
11:55:09,060 --> 11:55:10,060
certain specific set of skills since
16323
11:55:11,756 --> 11:55:12,756
it's so localized it also has higher
16324
11:55:14,160 --> 11:55:15,160
speed capabilities than a Wan and it's
16325
11:55:15,960 --> 11:55:16,960
often a lot less expensive so here's an
16326
11:55:18,660 --> 11:55:19,660
example of a local area network the
16327
11:55:22,560 --> 11:55:23,560
internet connectivity comes from the
16328
11:55:25,740 --> 11:55:26,740
server
16329
11:55:28,740 --> 11:55:29,740
which is going to also go out
16330
11:55:32,040 --> 11:55:33,040
to the WAN which would generally be
16331
11:55:35,096 --> 11:55:36,096
represented by a cloud the WAN being the
16332
11:55:38,340 --> 11:55:39,340
internet and we can see that there is a
16333
11:55:41,160 --> 11:55:42,160
switch here which connects each one of
16334
11:55:43,860 --> 11:55:44,860
these PCS
16335
11:55:45,616 --> 11:55:46,616
wirelessly perhaps has a PC connected
16336
11:55:48,240 --> 11:55:49,240
through it thanks to a wireless access
16337
11:55:51,060 --> 11:55:52,060
point perhaps connected to the switch or
16338
11:55:53,400 --> 11:55:54,400
router by the way here this server is
16339
11:55:56,220 --> 11:55:57,220
acting as a router and we might also
16340
11:55:58,320 --> 11:55:59,320
have the network connected printer very
16341
11:56:00,540 --> 11:56:01,540
simple but effective Lan here
16342
11:56:03,776 --> 11:56:04,776
now at the heart of every network is a
16343
11:56:07,320 --> 11:56:08,320
server the server is really what powers
16344
11:56:09,480 --> 11:56:10,480
the internet connection to every device
16345
11:56:11,160 --> 11:56:12,160
that's on the network and provides
16346
11:56:13,916 --> 11:56:14,916
um
16347
11:56:15,740 --> 11:56:16,740
devices on the network with resources
16348
11:56:18,860 --> 11:56:19,860
and other sorts of information now in
16349
11:56:22,500 --> 11:56:23,500
some cases we're not going to have a
16350
11:56:23,756 --> 11:56:24,756
server network but we're going to assume
16351
11:56:25,200 --> 11:56:26,200
here that we're talking about very
16352
11:56:26,700 --> 11:56:27,700
technical Network okay and the first
16353
11:56:29,040 --> 11:56:30,040
step to implementing a local area
16354
11:56:30,776 --> 11:56:31,776
network is to generally set up the
16355
11:56:33,180 --> 11:56:34,180
server or if we don't have a server to
16356
11:56:36,180 --> 11:56:37,180
set up the router
16357
11:56:37,860 --> 11:56:38,860
or the Soho router in a small office
16358
11:56:41,096 --> 11:56:42,096
home office remember the server is
16359
11:56:42,900 --> 11:56:43,900
really going to serve up resources
16360
11:56:46,200 --> 11:56:47,200
it's going to serve up a DHCP server so
16361
11:56:49,500 --> 11:56:50,500
on and so forth so the word Server
16362
11:56:51,000 --> 11:56:52,000
doesn't necessarily mean a freestanding
16363
11:56:53,040 --> 11:56:54,040
personal computer or a more powerful
16364
11:56:55,140 --> 11:56:56,140
computer it's really just the device
16365
11:56:56,936 --> 11:56:57,936
that's at the center of our Network
16366
11:56:59,580 --> 11:57:00,580
now usually we're going to do this with
16367
11:57:01,740 --> 11:57:02,740
some sort of professional setup
16368
11:57:03,300 --> 11:57:04,300
sometimes we'll have someone else come
16369
11:57:04,380 --> 11:57:05,380
in and sometimes we're going to do it
16370
11:57:05,340 --> 11:57:06,340
ourselves
16371
11:57:06,240 --> 11:57:07,240
now the network topography and design is
16372
11:57:09,116 --> 11:57:10,116
also pretty important we need to figure
16373
11:57:10,560 --> 11:57:11,560
out how we're going to set up the
16374
11:57:12,240 --> 11:57:13,240
network we talked about different
16375
11:57:13,500 --> 11:57:14,500
topographies previously so we probably
16376
11:57:16,740 --> 11:57:17,740
are going to want some sort of star
16377
11:57:18,960 --> 11:57:19,960
Network
16378
11:57:20,160 --> 11:57:21,160
if you recall what that is we might for
16379
11:57:22,560 --> 11:57:23,560
some reason have a ring if we have a
16380
11:57:24,900 --> 11:57:25,900
really intense local area network all
16381
11:57:27,116 --> 11:57:28,116
this is usually going to be used in a
16382
11:57:28,380 --> 11:57:29,380
Wan setting so really what we're going
16383
11:57:30,000 --> 11:57:31,000
to see usually is a star
16384
11:57:34,200 --> 11:57:35,200
and as you can see everything is
16385
11:57:36,060 --> 11:57:37,060
hardwired and this is a bird's eye view
16386
11:57:39,240 --> 11:57:40,240
of how we're going to connect this
16387
11:57:41,756 --> 11:57:42,756
network
16388
11:57:44,700 --> 11:57:45,700
so you can see we see each device
16389
11:57:46,916 --> 11:57:47,916
plugged up we see where every device
16390
11:57:48,900 --> 11:57:49,900
plugs in for instance this printer plugs
16391
11:57:50,756 --> 11:57:51,756
up directly to Mike's PC so if you're
16392
11:57:52,680 --> 11:57:53,680
having a trouble problem with the
16393
11:57:54,060 --> 11:57:55,060
printer we know that actually the PC
16394
11:57:56,460 --> 11:57:57,460
could be the problem not necessarily
16395
11:57:58,200 --> 11:57:59,200
this chord here and so knowing where
16396
11:58:00,596 --> 11:58:01,596
everything is set up and how everything
16397
11:58:02,220 --> 11:58:03,220
is set up is really important as you go
16398
11:58:04,860 --> 11:58:05,860
forth and of course important before I
16399
11:58:06,720 --> 11:58:07,720
start to create a huge Network by the
16400
11:58:10,680 --> 11:58:11,680
way your network and your plan
16401
11:58:12,540 --> 11:58:13,540
probably a lot more complex than this
16402
11:58:14,276 --> 11:58:15,276
but try drawing out your network at home
16403
11:58:16,500 --> 11:58:17,500
and see if you can do it as well
16404
11:58:19,256 --> 11:58:20,256
now backups are extremely important when
16405
11:58:22,200 --> 11:58:23,200
I have especially Enterprise setup the
16406
11:58:24,900 --> 11:58:25,900
loss of data that can occur could take
16407
11:58:27,180 --> 11:58:28,180
us out of operating and if I'm talking
16408
11:58:29,220 --> 11:58:30,220
about a network that is running Bank
16409
11:58:32,400 --> 11:58:33,400
information or health care then I really
16410
11:58:34,980 --> 11:58:35,980
need to potentially stop or avoid this
16411
11:58:37,980 --> 11:58:38,980
critical loss of data so regular backups
16412
11:58:40,140 --> 11:58:41,140
are key now there are a lot of different
16413
11:58:41,700 --> 11:58:42,700
ways to do this and we'll talk about
16414
11:58:43,320 --> 11:58:44,320
specifically some of the difference
16415
11:58:45,776 --> 11:58:46,776
between an incremental backup
16416
11:58:49,500 --> 11:58:50,500
and a differential backup
16417
11:58:52,560 --> 11:58:53,560
disgusting a plus as well
16418
11:58:55,140 --> 11:58:56,140
but there are some other Surefire ways
16419
11:58:57,416 --> 11:58:58,416
that we want to do this first all users
16420
11:58:59,520 --> 11:59:00,520
on the networks need to be regularly
16421
11:59:00,960 --> 11:59:01,960
saving and backing up their own work
16422
11:59:02,460 --> 11:59:03,460
then we might want to have an outside
16423
11:59:04,560 --> 11:59:05,560
service also taking care of our backups
16424
11:59:07,140 --> 11:59:08,140
so I might want to have the backup going
16425
11:59:10,320 --> 11:59:11,320
out
16426
11:59:11,220 --> 11:59:12,220
to a cloud or to a Wan in this case I
16427
11:59:14,580 --> 11:59:15,580
probably have and this computer is
16428
11:59:15,900 --> 11:59:16,900
representing My Lan all of the
16429
11:59:18,060 --> 11:59:19,060
information going to a central service
16430
11:59:19,916 --> 11:59:20,916
and then going out if I have a server
16431
11:59:23,340 --> 11:59:24,340
and all of the devices are hooked up
16432
11:59:26,460 --> 11:59:27,460
to the server then they're going to feed
16433
11:59:28,616 --> 11:59:29,616
the server with the information once
16434
11:59:30,776 --> 11:59:31,776
that information is on the server then I
16435
11:59:32,820 --> 11:59:33,820
can make sure that battle goes out to
16436
11:59:34,256 --> 11:59:35,256
the cloud the important thing is to
16437
11:59:36,180 --> 11:59:37,180
centralize where your information is
16438
11:59:37,680 --> 11:59:38,680
being saved if I have for instance data
16439
11:59:40,380 --> 11:59:41,380
being saved to
16440
11:59:42,660 --> 11:59:43,660
various computers and those computers
16441
11:59:45,060 --> 11:59:46,060
don't have a central place to store all
16442
11:59:47,276 --> 11:59:48,276
the data then backing up simply the
16443
11:59:49,616 --> 11:59:50,616
server is not going to do it a map to go
16444
11:59:51,116 --> 11:59:52,116
back up every individual computer and
16445
11:59:52,980 --> 11:59:53,980
that really doesn't work so what we
16446
11:59:54,960 --> 11:59:55,960
really want to have is a centralized
16447
11:59:57,240 --> 11:59:58,240
backup system and sometimes we want to
16448
11:59:59,460 --> 12:00:00,460
have redundancy
16449
12:00:02,460 --> 12:00:03,460
in this system
16450
12:00:04,256 --> 12:00:05,256
by not only backing it up locally but
16451
12:00:06,540 --> 12:00:07,540
backing it up out to the WAN or
16452
12:00:09,300 --> 12:00:10,300
alternatively having tapes that we're
16453
12:00:10,916 --> 12:00:11,916
going to take off site in case God
16454
12:00:13,320 --> 12:00:14,320
forbid something happened to my backup
16455
12:00:15,300 --> 12:00:16,300
plan
16456
12:00:16,860 --> 12:00:17,860
now it's also important that we document
16457
12:00:19,020 --> 12:00:20,020
our Network and once we've documented it
16458
12:00:20,936 --> 12:00:21,936
we need to continually audit where our
16459
12:00:22,680 --> 12:00:23,680
Network's weaknesses and strengths are
16460
12:00:24,300 --> 12:00:25,300
so I want to keep track of everything
16461
12:00:25,860 --> 12:00:26,860
that's on the network including the
16462
12:00:28,680 --> 12:00:29,680
hardware the software
16463
12:00:30,680 --> 12:00:31,680
diagrams that we have numbers serial
16464
12:00:33,776 --> 12:00:34,776
numbers Etc we also need to audit the
16465
12:00:36,180 --> 12:00:37,180
network for security strengths and
16466
12:00:37,740 --> 12:00:38,740
weaknesses we might do this by using a
16467
12:00:39,660 --> 12:00:40,660
port scanner
16468
12:00:41,936 --> 12:00:42,936
by having some sort of centralized virus
16469
12:00:44,460 --> 12:00:45,460
scan program like we'll see in a minute
16470
12:00:46,800 --> 12:00:47,800
and maybe even by hiring an outside
16471
12:00:48,480 --> 12:00:49,480
security firm to try to hack into my
16472
12:00:50,580 --> 12:00:51,580
system so I can see where the weaknesses
16473
12:00:52,916 --> 12:00:53,916
and strengths are
16474
12:00:54,900 --> 12:00:55,900
all this information is going to be key
16475
12:00:57,300 --> 12:00:58,300
in recovering
16476
12:00:59,756 --> 12:01:00,756
in case of major data loss
16477
12:01:04,200 --> 12:01:05,200
and that's the reason I want to always
16478
12:01:05,580 --> 12:01:06,580
just keep a nice long paper trail
16479
12:01:08,096 --> 12:01:09,096
sometimes you might want to print this
16480
12:01:09,360 --> 12:01:10,360
stuff off too because again the computer
16481
12:01:10,980 --> 12:01:11,980
goes down I can't access anything that's
16482
12:01:12,660 --> 12:01:13,660
digital or throw it up in the cloud then
16483
12:01:14,820 --> 12:01:15,820
I don't have to worry about it
16484
12:01:17,040 --> 12:01:18,040
now when we kept the management and
16485
12:01:18,720 --> 12:01:19,720
troubleshooting we always want to make
16486
12:01:19,860 --> 12:01:20,860
sure the network is running smoothly and
16487
12:01:22,080 --> 12:01:23,080
since you're the administrator you're
16488
12:01:23,820 --> 12:01:24,820
the person who has to be monitoring and
16489
12:01:25,800 --> 12:01:26,800
managing everything that's going on now
16490
12:01:27,720 --> 12:01:28,720
when there are issues you want to
16491
12:01:29,640 --> 12:01:30,640
troubleshoot and solve the issues where
16492
12:01:31,200 --> 12:01:32,200
they arise using the OSI model can be
16493
12:01:34,080 --> 12:01:35,080
really helpful in this case because you
16494
12:01:35,756 --> 12:01:36,756
can determine where the issue is
16495
12:01:37,500 --> 12:01:38,500
occurring for instance if I'm having a
16496
12:01:39,596 --> 12:01:40,596
trouble getting out to a certain website
16497
12:01:43,020 --> 12:01:44,020
but everyone seems to be getting out to
16498
12:01:45,000 --> 12:01:46,000
information then maybe the DNS is the
16499
12:01:47,400 --> 12:01:48,400
problem if for instance new devices
16500
12:01:49,680 --> 12:01:50,680
can't get on the network but if I
16501
12:01:51,360 --> 12:01:52,360
manually assign them an IP address it
16502
12:01:53,096 --> 12:01:54,096
does work well then probably my DHCP
16503
12:01:55,140 --> 12:01:56,140
server is is getting funky again this is
16504
12:01:58,436 --> 12:01:59,436
just an overview we're going to talk
16505
12:01:59,640 --> 12:02:00,640
about all this in more specifics as we
16506
12:02:01,380 --> 12:02:02,380
go forward
16507
12:02:02,700 --> 12:02:03,700
so I need to take a look at what the
16508
12:02:04,380 --> 12:02:05,380
error is figure out what the problem is
16509
12:02:05,936 --> 12:02:06,936
and get to the root issue especially
16510
12:02:09,116 --> 12:02:10,116
because what I'm really going for here
16511
12:02:10,560 --> 12:02:11,560
is what's called five nines which means
16512
12:02:12,596 --> 12:02:13,596
I want to be up
16513
12:02:14,240 --> 12:02:15,240
99.999 of the time
16514
12:02:17,060 --> 12:02:18,060
that's like five minutes of downtime per
16515
12:02:19,800 --> 12:02:20,800
year that five minutes however can be
16516
12:02:22,256 --> 12:02:23,256
really a big issue this also means I
16517
12:02:24,720 --> 12:02:25,720
want to be updating with Windows updates
16518
12:02:26,580 --> 12:02:27,580
and I want to be providing as much
16519
12:02:28,436 --> 12:02:29,436
information as possible to my network
16520
12:02:31,320 --> 12:02:32,320
and my network staff and even the
16521
12:02:33,740 --> 12:02:34,740
individuals who are using the network as
16522
12:02:35,820 --> 12:02:36,820
possible
16523
12:02:37,500 --> 12:02:38,500
finally when it comes to security and
16524
12:02:39,180 --> 12:02:40,180
virus protection I want to make sure to
16525
12:02:41,096 --> 12:02:42,096
audit and protect prevent the attacks
16526
12:02:43,200 --> 12:02:44,200
before they can happen so I'm going to
16527
12:02:44,880 --> 12:02:45,880
audit it and once I audit I can see what
16528
12:02:47,340 --> 12:02:48,340
sort of the issues are if I notice that
16529
12:02:49,140 --> 12:02:50,140
there's no Virus Protection Program then
16530
12:02:51,000 --> 12:02:52,000
I'm going to want to use some antivirus
16531
12:02:52,560 --> 12:02:53,560
software if I notice that there are open
16532
12:02:56,276 --> 12:02:57,276
ports getting out to the server through
16533
12:02:59,040 --> 12:03:00,040
the firewall then I'm going to want to
16534
12:03:00,596 --> 12:03:01,596
use that if I notice there isn't a
16535
12:03:01,800 --> 12:03:02,800
firewall I'm going to want to have to
16536
12:03:03,300 --> 12:03:04,300
put a firewall up so basically all the
16537
12:03:05,700 --> 12:03:06,700
things I can do there's no one size fits
16538
12:03:08,040 --> 12:03:09,040
all practice what you really have to do
16539
12:03:09,360 --> 12:03:10,360
is use the skills that you have in order
16540
12:03:11,400 --> 12:03:12,400
to audit the system and then prevent the
16541
12:03:14,276 --> 12:03:15,276
attacks before they happen using a
16542
12:03:16,080 --> 12:03:17,080
number of different tools might even use
16543
12:03:17,880 --> 12:03:18,880
something called an IPS or IDs which
16544
12:03:20,400 --> 12:03:21,400
would be uh
16545
12:03:22,520 --> 12:03:23,520
intrusion protection or intrusion
16546
12:03:24,776 --> 12:03:25,776
detection service or scanner
16547
12:03:28,616 --> 12:03:29,616
all right so just to go back over this
16548
12:03:30,480 --> 12:03:31,480
it was a very broad overview of what a
16549
12:03:32,580 --> 12:03:33,580
local area network is and some of the
16550
12:03:34,080 --> 12:03:35,080
things that we need to do in setting up
16551
12:03:35,520 --> 12:03:36,520
maintaining a land including creating
16552
12:03:37,380 --> 12:03:38,380
and having a network plan performing
16553
12:03:39,720 --> 12:03:40,720
regular backups providing documentation
16554
12:03:42,116 --> 12:03:43,116
keeping holding on to that documentation
16555
12:03:44,060 --> 12:03:45,060
auditing our Network to identify
16556
12:03:46,500 --> 12:03:47,500
weaknesses which is the main reason for
16557
12:03:48,416 --> 12:03:49,416
an audit we also might want to use the
16558
12:03:50,700 --> 12:03:51,700
audit to
16559
12:03:51,800 --> 12:03:52,800
identify bottlenecks or slow issues that
16560
12:03:56,160 --> 12:03:57,160
are going to cause speed issues
16561
12:04:00,776 --> 12:04:01,776
so on and then of course having proper
16562
12:04:03,000 --> 12:04:04,000
security such as virus scan programs
16563
12:04:05,160 --> 12:04:06,160
intrusion detection prevention systems
16564
12:04:07,436 --> 12:04:08,436
firewalls and so on we're going to talk
16565
12:04:09,776 --> 12:04:10,776
all about this and more in the coming
16566
12:04:11,580 --> 12:04:12,580
lessons but this was just a broad
16567
12:04:13,200 --> 12:04:14,200
overview to get a sort of set up
16568
12:04:19,660 --> 12:04:20,660
[Music]
16569
12:04:28,340 --> 12:04:29,340
thank you
16570
12:04:42,000 --> 12:04:43,000
local area networks switching
16571
12:04:45,840 --> 12:04:46,840
so in the last module we talked about
16572
12:04:47,700 --> 12:04:48,700
local area networks in general what they
16573
12:04:49,980 --> 12:04:50,980
do how we set them up how we administer
16574
12:04:52,020 --> 12:04:53,020
them but in order to have a functioning
16575
12:04:55,080 --> 12:04:56,080
local area network one of the most
16576
12:04:57,596 --> 12:04:58,596
important developments that we had was
16577
12:05:00,416 --> 12:05:01,416
called switching if you recall earlier
16578
12:05:02,756 --> 12:05:03,756
on we talked about the OSI model and if
16579
12:05:05,400 --> 12:05:06,400
you recall the OSI model went from level
16580
12:05:07,680 --> 12:05:08,680
one all the way up to level seven
16581
12:05:12,480 --> 12:05:13,480
now level one was the physical layer and
16582
12:05:15,540 --> 12:05:16,540
on there we talked briefly about a
16583
12:05:17,936 --> 12:05:18,936
device called a hub
16584
12:05:20,400 --> 12:05:21,400
now the problem with the Hub was
16585
12:05:22,560 --> 12:05:23,560
whenever data
16586
12:05:24,660 --> 12:05:25,660
went from one computer into the Hub
16587
12:05:28,380 --> 12:05:29,380
The Hub spouted all of that data out
16588
12:05:31,800 --> 12:05:32,800
to all the other computers on the
16589
12:05:33,540 --> 12:05:34,540
network this created a lot of broadcast
16590
12:05:35,700 --> 12:05:36,700
traffic because the Hub itself worked on
16591
12:05:40,320 --> 12:05:41,320
the physical layer all it did was repeat
16592
12:05:43,080 --> 12:05:44,080
all of the bits that went into it out to
16593
12:05:45,660 --> 12:05:46,660
all the other devices
16594
12:05:47,340 --> 12:05:48,340
but now we have something and we've had
16595
12:05:49,800 --> 12:05:50,800
for quite a while a thing called a
16596
12:05:52,020 --> 12:05:53,020
switch and this allows for switching
16597
12:05:53,880 --> 12:05:54,880
which operates mostly on level two
16598
12:05:58,080 --> 12:05:59,080
of the OSI model which if you recall is
16599
12:06:00,540 --> 12:06:01,540
the
16600
12:06:01,860 --> 12:06:02,860
data link layer
16601
12:06:04,140 --> 12:06:05,140
switching allows us to have a fully
16602
12:06:06,300 --> 12:06:07,300
functioning local area network because
16603
12:06:08,820 --> 12:06:09,820
it allows devices to talk
16604
12:06:13,200 --> 12:06:14,200
using the MAC address or the physical
16605
12:06:15,776 --> 12:06:16,776
address of the computer
16606
12:06:18,360 --> 12:06:19,360
so in this module we're going to talk
16607
12:06:20,820 --> 12:06:21,820
more in depth about what a switch is
16608
12:06:24,300 --> 12:06:25,300
how a switch operates which I just
16609
12:06:26,340 --> 12:06:27,340
touched upon a bit and then I'm going to
16610
12:06:28,740 --> 12:06:29,740
talk about a couple Advanced switches
16611
12:06:31,380 --> 12:06:32,380
you need to know about for the network
16612
12:06:32,880 --> 12:06:33,880
plus exam these are the multi-layer
16613
12:06:35,700 --> 12:06:36,700
switch also called a layer 3 switch or a
16614
12:06:41,340 --> 12:06:42,340
Smart Switch
16615
12:06:43,680 --> 12:06:44,680
and then we're going to talk about a
16616
12:06:45,416 --> 12:06:46,416
Content switch which as the name implies
16617
12:06:48,180 --> 12:06:49,180
deals with the content in the packet not
16618
12:06:50,936 --> 12:06:51,936
just relaying the packet of data itself
16619
12:06:55,140 --> 12:06:56,140
so a switch is an extremely important
16620
12:06:58,616 --> 12:06:59,616
part of a functioning Network so let's
16621
12:07:01,080 --> 12:07:02,080
look for a minute about a light switch a
16622
12:07:03,776 --> 12:07:04,776
light switch essentially has two pieces
16623
12:07:05,400 --> 12:07:06,400
of wire attached to it if we look at
16624
12:07:08,460 --> 12:07:09,460
like so
16625
12:07:11,460 --> 12:07:12,460
I'll put the little switch right there
16626
12:07:13,080 --> 12:07:14,080
and when the switch is flipped in One
16627
12:07:16,080 --> 12:07:17,080
Direction the circuit is completed when
16628
12:07:19,560 --> 12:07:20,560
it's flipped the other way then the
16629
12:07:22,560 --> 12:07:23,560
circuit is sort of broken and so the
16630
12:07:24,300 --> 12:07:25,300
light turns off
16631
12:07:26,276 --> 12:07:27,276
in a way an ethernet switch follows the
16632
12:07:28,980 --> 12:07:29,980
same principle except it's not only
16633
12:07:30,900 --> 12:07:31,900
attached to one single wire and cable
16634
12:07:33,480 --> 12:07:34,480
but to many some switches can even have
16635
12:07:36,300 --> 12:07:37,300
upwards of 200 cables attached to them
16636
12:07:39,776 --> 12:07:40,776
now these ethernet switches are used to
16637
12:07:42,180 --> 12:07:43,180
connect many if not all of the devices
16638
12:07:44,640 --> 12:07:45,640
on network and it establishes a flow of
16639
12:07:49,140 --> 12:07:50,140
data between them
16640
12:07:51,180 --> 12:07:52,180
this switch like a light switch makes a
16641
12:07:54,360 --> 12:07:55,360
connection between two different cables
16642
12:07:56,160 --> 12:07:57,160
and allows the data to flow specifically
16643
12:07:58,740 --> 12:07:59,740
between those two devices
16644
12:08:00,660 --> 12:08:01,660
now Lan switches are used to send data
16645
12:08:04,140 --> 12:08:05,140
from a single device to another
16646
12:08:06,860 --> 12:08:07,860
sometimes uh the and sometimes even
16647
12:08:09,660 --> 12:08:10,660
multiple devices there are devices as I
16648
12:08:12,416 --> 12:08:13,416
said called hubs but these do something
16649
12:08:14,040 --> 12:08:15,040
different
16650
12:08:15,180 --> 12:08:16,180
so what the switch really does here is
16651
12:08:17,936 --> 12:08:18,936
it allows data sent from one device to
16652
12:08:20,580 --> 12:08:21,580
go specifically
16653
12:08:22,380 --> 12:08:23,380
to the other device that it's meant for
16654
12:08:24,060 --> 12:08:25,060
and it does this
16655
12:08:25,680 --> 12:08:26,680
because it knows the MAC address
16656
12:08:29,276 --> 12:08:30,276
that it wants to send to now it doesn't
16657
12:08:32,096 --> 12:08:33,096
necessarily know where that Mac address
16658
12:08:34,916 --> 12:08:35,916
is on the network all it knows and it
16659
12:08:37,560 --> 12:08:38,560
puts this into the packet remember we
16660
12:08:39,060 --> 12:08:40,060
talked about that it puts it into the
16661
12:08:40,436 --> 12:08:41,436
header of the packet
16662
12:08:42,360 --> 12:08:43,360
the address which would be sort of like
16663
12:08:44,580 --> 12:08:45,580
the phone number or the social security
16664
12:08:46,800 --> 12:08:47,800
number of the computer that wants to
16665
12:08:50,040 --> 12:08:51,040
receive the data the switch then has a
16666
12:08:52,860 --> 12:08:53,860
table that says in each port
16667
12:08:56,400 --> 12:08:57,400
so if we had Port 1 2 3 4 and 5 it would
16668
12:09:02,340 --> 12:09:03,340
say
16669
12:09:03,540 --> 12:09:04,540
the MAC address connected to each port
16670
12:09:06,180 --> 12:09:07,180
and so when Port 1 sends data meant for
16671
12:09:10,080 --> 12:09:11,080
a MAC address
16672
12:09:11,640 --> 12:09:12,640
it knows oh I'm going to send that to
16673
12:09:13,800 --> 12:09:14,800
Port 5.
16674
12:09:15,240 --> 12:09:16,240
now it could also do this for multiple
16675
12:09:17,096 --> 12:09:18,096
for instance I'm going to send it to
16676
12:09:18,720 --> 12:09:19,720
Port 2 and port 5.
16677
12:09:20,936 --> 12:09:21,936
the key difference here as I pointed out
16678
12:09:22,916 --> 12:09:23,916
in the very first slide was rather than
16679
12:09:25,500 --> 12:09:26,500
a hub
16680
12:09:26,820 --> 12:09:27,820
which broadcasts out
16681
12:09:31,380 --> 12:09:32,380
to all devices
16682
12:09:33,240 --> 12:09:34,240
the switch creates a single switch
16683
12:09:38,040 --> 12:09:39,040
between two specific devices and closes
16684
12:09:41,096 --> 12:09:42,096
a connection
16685
12:09:42,360 --> 12:09:43,360
what this does in effect therefore is
16686
12:09:45,116 --> 12:09:46,116
reduce broadcast traffic and allow the
16687
12:09:47,460 --> 12:09:48,460
network to run much more efficiently
16688
12:09:49,800 --> 12:09:50,800
than a hub allowed
16689
12:09:52,380 --> 12:09:53,380
now there was a time when networking
16690
12:09:54,840 --> 12:09:55,840
devices only served one purpose and
16691
12:09:57,416 --> 12:09:58,416
their functions were specific to that
16692
12:09:59,096 --> 12:10:00,096
type of device but over years things
16693
12:10:01,020 --> 12:10:02,020
have evolved so now devices can do
16694
12:10:03,060 --> 12:10:04,060
multiple things now we see this
16695
12:10:06,300 --> 12:10:07,300
multi-layer switch or what you might
16696
12:10:08,160 --> 12:10:09,160
also see as a layer three switch or a
16697
12:10:11,220 --> 12:10:12,220
Smart Switch
16698
12:10:12,776 --> 12:10:13,776
what it does is it is not only a switch
16699
12:10:15,000 --> 12:10:16,000
it's also a router this is the reason
16700
12:10:17,700 --> 12:10:18,700
why it's called a layer 3 switch I
16701
12:10:19,800 --> 12:10:20,800
brought up the OSI model on the very
16702
12:10:21,300 --> 12:10:22,300
first slide
16703
12:10:22,916 --> 12:10:23,916
layer 1 physical
16704
12:10:26,880 --> 12:10:27,880
layer 2 data link
16705
12:10:30,720 --> 12:10:31,720
and if you recall layer three let's use
16706
12:10:32,820 --> 12:10:33,820
our mnemonic device please do not throw
16707
12:10:37,680 --> 12:10:38,680
sausage pizza away so this is the
16708
12:10:40,020 --> 12:10:41,020
network layer
16709
12:10:41,880 --> 12:10:42,880
if you recall we mentioned briefly that
16710
12:10:44,220 --> 12:10:45,220
routers which we'll talk about in more
16711
12:10:45,776 --> 12:10:46,776
depth later
16712
12:10:46,916 --> 12:10:47,916
operate on layer three that's because
16713
12:10:50,276 --> 12:10:51,276
IP addresses operate on layer three so a
16714
12:10:54,480 --> 12:10:55,480
switch can not only look at the MAC
16715
12:10:56,400 --> 12:10:57,400
address
16716
12:10:58,616 --> 12:10:59,616
but a multi-layer switch one that
16717
12:11:01,020 --> 12:11:02,020
operates not only in Layer Two but also
16718
12:11:02,880 --> 12:11:03,880
on layer three
16719
12:11:04,436 --> 12:11:05,436
can also look at IP addresses
16720
12:11:09,360 --> 12:11:10,360
so because this switch operates as both
16721
12:11:13,560 --> 12:11:14,560
a router and a switch it can send
16722
12:11:17,580 --> 12:11:18,580
information between several different
16723
12:11:19,320 --> 12:11:20,320
networks so here for instance I have
16724
12:11:21,360 --> 12:11:22,360
Network a and network B and let's see
16725
12:11:24,116 --> 12:11:25,116
this PC wants to talk with the server
16726
12:11:27,720 --> 12:11:28,720
on network B in the old system uh unless
16727
12:11:31,860 --> 12:11:32,860
network uh unless the server was
16728
12:11:34,380 --> 12:11:35,380
actually connected directly to the
16729
12:11:36,416 --> 12:11:37,416
switch there would be no way for the two
16730
12:11:38,700 --> 12:11:39,700
networks to sort of speak to one another
16731
12:11:40,380 --> 12:11:41,380
but because we have a device here
16732
12:11:43,380 --> 12:11:44,380
that's perhaps operating as a switch and
16733
12:11:46,800 --> 12:11:47,800
a router
16734
12:11:48,540 --> 12:11:49,540
it can route the data onto a different
16735
12:11:51,776 --> 12:11:52,776
network using an IP address
16736
12:11:57,180 --> 12:11:58,180
in some ways you could think about this
16737
12:11:59,400 --> 12:12:00,400
as the Advent of the area code
16738
12:12:03,596 --> 12:12:04,596
when we had a phone number
16739
12:12:05,580 --> 12:12:06,580
which was only
16740
12:12:07,860 --> 12:12:08,860
five digits or uh sorry seven digits
16741
12:12:11,220 --> 12:12:12,220
such as
16742
12:12:13,320 --> 12:12:14,320
um seven two three
16743
12:12:15,256 --> 12:12:16,256
five four one one we could talk to
16744
12:12:18,840 --> 12:12:19,840
anyone within our local network if we
16745
12:12:21,480 --> 12:12:22,480
knew
16746
12:12:22,500 --> 12:12:23,500
this number when we added the area code
16747
12:12:25,256 --> 12:12:26,256
we were allowed to then dial out to
16748
12:12:28,020 --> 12:12:29,020
other states and then we were allowed by
16749
12:12:30,596 --> 12:12:31,596
putting an international code to dial
16750
12:12:32,640 --> 12:12:33,640
out to different countries so we're
16751
12:12:35,160 --> 12:12:36,160
allowed to go then outside of our
16752
12:12:36,776 --> 12:12:37,776
specific Network in this way we're not
16753
12:12:39,480 --> 12:12:40,480
just dealing with Mac addresses we're
16754
12:12:41,520 --> 12:12:42,520
dealing with IP addresses and as we've
16755
12:12:43,916 --> 12:12:44,916
talked about IP addresses
16756
12:12:46,500 --> 12:12:47,500
are assigned by for instance a DHCP
16757
12:12:49,436 --> 12:12:50,436
server and so as a result they're more
16758
12:12:51,540 --> 12:12:52,540
temporary they're not hardwired onto the
16759
12:12:53,520 --> 12:12:54,520
device and it not only allows for
16760
12:12:55,320 --> 12:12:56,320
routing but it makes it a little more
16761
12:12:56,936 --> 12:12:57,936
complex to figure out where a device is
16762
12:12:59,040 --> 12:13:00,040
at any one time we'll talk more about
16763
12:13:00,660 --> 12:13:01,660
that in the next module the important
16764
12:13:02,640 --> 12:13:03,640
thing here to realize though is that a
16765
12:13:05,520 --> 12:13:06,520
multi-layer switch operates both as a
16766
12:13:08,340 --> 12:13:09,340
router
16767
12:13:09,300 --> 12:13:10,300
and as a switch because it works on
16768
12:13:12,480 --> 12:13:13,480
layer 3 and layer 2 which means it not
16769
12:13:16,020 --> 12:13:17,020
only reads
16770
12:13:17,340 --> 12:13:18,340
Mac addresses
16771
12:13:19,080 --> 12:13:20,080
but also IP addresses
16772
12:13:24,416 --> 12:13:25,416
now the next type of switch I want to
16773
12:13:25,916 --> 12:13:26,916
mention is something called a Content
16774
12:13:27,720 --> 12:13:28,720
switch the name content should give away
16775
12:13:30,116 --> 12:13:31,116
what we're about to talk about here now
16776
12:13:32,160 --> 12:13:33,160
these are not really used as much as we
16777
12:13:34,140 --> 12:13:35,140
see in today's networks because they're
16778
12:13:36,300 --> 12:13:37,300
quite costly but a Content switch will
16779
12:13:39,900 --> 12:13:40,900
actually analyze the data it receives
16780
12:13:42,116 --> 12:13:43,116
and forward it based on its content only
16781
12:13:45,660 --> 12:13:46,660
so rather than dealing with simply an IP
16782
12:13:49,200 --> 12:13:50,200
address or Mac address it actually looks
16783
12:13:51,480 --> 12:13:52,480
at what's inside
16784
12:13:53,936 --> 12:13:54,936
of the of the packet if we have a MAC
16785
12:13:57,180 --> 12:13:58,180
address here and then we put an IP
16786
12:13:59,756 --> 12:14:00,756
address on the outside of that in order
16787
12:14:01,380 --> 12:14:02,380
to tell where to go it's actually going
16788
12:14:03,240 --> 12:14:04,240
to look inside and look at the data and
16789
12:14:06,000 --> 12:14:07,000
determine where that content is going to
16790
12:14:08,340 --> 12:14:09,340
go
16791
12:14:09,000 --> 12:14:10,000
these switches are also sometimes called
16792
12:14:11,360 --> 12:14:12,360
load bearing switches
16793
12:14:15,180 --> 12:14:16,180
because they can evenly distribute data
16794
12:14:18,436 --> 12:14:19,436
based on the type of data there is in
16795
12:14:20,700 --> 12:14:21,700
the appropriate destinations which can
16796
12:14:22,500 --> 12:14:23,500
alleviate stress on a single server or
16797
12:14:25,140 --> 12:14:26,140
device
16798
12:14:26,160 --> 12:14:27,160
so for instance if I erase all this for
16799
12:14:28,616 --> 12:14:29,616
a second let's say we have
16800
12:14:30,300 --> 12:14:31,300
for some reason and let's say we have a
16801
12:14:32,340 --> 12:14:33,340
router right here which allows us to
16802
12:14:34,140 --> 12:14:35,140
connect out to the internet and then
16803
12:14:36,060 --> 12:14:37,060
information comes in straight from the
16804
12:14:37,860 --> 12:14:38,860
router to the content switch and we
16805
12:14:39,900 --> 12:14:40,900
don't know where the information is set
16806
12:14:41,756 --> 12:14:42,756
for or let's say we have
16807
12:14:44,936 --> 12:14:45,936
six different clients or servers it
16808
12:14:47,580 --> 12:14:48,580
doesn't really matter that each could
16809
12:14:49,256 --> 12:14:50,256
operate under the same sort of IP
16810
12:14:52,680 --> 12:14:53,680
address for instance we're going to put
16811
12:14:54,776 --> 12:14:55,776
them all together or group them the
16812
12:14:56,520 --> 12:14:57,520
content switch can say which one it's
16813
12:14:58,560 --> 12:14:59,560
going to go to based on the type of
16814
12:15:00,480 --> 12:15:01,480
information it's receiving so for
16815
12:15:02,276 --> 12:15:03,276
instance email is probably going to go
16816
12:15:04,500 --> 12:15:05,500
to one computer whereas web is going to
16817
12:15:07,200 --> 12:15:08,200
go to another whereas the FTP might go
16818
12:15:09,060 --> 12:15:10,060
to another and the packet itself doesn't
16819
12:15:11,160 --> 12:15:12,160
have to know which computer it's going
16820
12:15:12,596 --> 12:15:13,596
to the packet just has to have an IP
16821
12:15:15,596 --> 12:15:16,596
address and or Mac address and then the
16822
12:15:18,240 --> 12:15:19,240
contents which itself based on the
16823
12:15:20,040 --> 12:15:21,040
content is going to send that over
16824
12:15:21,116 --> 12:15:22,116
another way to think about this is if
16825
12:15:23,580 --> 12:15:24,580
I'm dealing with some sort of firewall
16826
12:15:26,880 --> 12:15:27,880
and I want the firewall to put certain
16827
12:15:31,080 --> 12:15:32,080
types of data into a
16828
12:15:33,840 --> 12:15:34,840
um
16829
12:15:35,220 --> 12:15:36,220
filtered
16830
12:15:36,960 --> 12:15:37,960
area
16831
12:15:38,276 --> 12:15:39,276
that needs to be scanned for viruses so
16832
12:15:40,740 --> 12:15:41,740
this is really going to help me
16833
12:15:41,880 --> 12:15:42,880
alleviate uh certain processes
16834
12:15:46,256 --> 12:15:47,256
and also help keep my network safer and
16835
12:15:48,660 --> 12:15:49,660
we'll talk about other devices that do
16836
12:15:50,040 --> 12:15:51,040
this as well
16837
12:15:51,116 --> 12:15:52,116
but when we're dealing with the content
16838
12:15:52,616 --> 12:15:53,616
we're dealing with further up on the OSI
16839
12:15:54,960 --> 12:15:55,960
model so we're not just dealing with
16840
12:15:56,400 --> 12:15:57,400
layer one or two or three even we might
16841
12:15:58,916 --> 12:15:59,916
even be dealing with layer four to some
16842
12:16:01,080 --> 12:16:02,080
extent
16843
12:16:03,060 --> 12:16:04,060
so just to recap we first talked about
16844
12:16:05,580 --> 12:16:06,580
what a switch is a switch again allows
16845
12:16:09,360 --> 12:16:10,360
for a direct connection
16846
12:16:12,480 --> 12:16:13,480
between
16847
12:16:13,860 --> 12:16:14,860
two devices
16848
12:16:20,160 --> 12:16:21,160
or more
16849
12:16:21,840 --> 12:16:22,840
the important thing to hear to realize
16850
12:16:23,400 --> 12:16:24,400
is that the devices communicate directly
16851
12:16:25,560 --> 12:16:26,560
because the switch creates a circuit
16852
12:16:28,500 --> 12:16:29,500
between those two devices Within
16853
12:16:31,916 --> 12:16:32,916
a box based on ports
16854
12:16:35,460 --> 12:16:36,460
now how it does this is it creates a
16855
12:16:37,860 --> 12:16:38,860
table
16856
12:16:40,680 --> 12:16:41,680
defining which ports are connected
16857
12:16:43,800 --> 12:16:44,800
to which Mac addresses again a MAC
16858
12:16:46,560 --> 12:16:47,560
address is the physical address that's
16859
12:16:49,560 --> 12:16:50,560
built into a device when it's made
16860
12:16:52,980 --> 12:16:53,980
this is different from a hub which just
16861
12:16:55,740 --> 12:16:56,740
broadcasts everything so if we were to
16862
12:16:58,256 --> 12:16:59,256
create an analogy we could say broadcast
16863
12:17:00,596 --> 12:17:01,596
which would mean all the data going out
16864
12:17:03,060 --> 12:17:04,060
to every other device
16865
12:17:04,616 --> 12:17:05,616
is
16866
12:17:05,936 --> 12:17:06,936
to a hub
16867
12:17:08,340 --> 12:17:09,340
what unicast
16868
12:17:11,160 --> 12:17:12,160
or multicast
16869
12:17:15,000 --> 12:17:16,000
is
16870
12:17:17,400 --> 12:17:18,400
to a switch
16871
12:17:19,680 --> 12:17:20,680
we also looked at some Advanced switches
16872
12:17:21,596 --> 12:17:22,596
you need to know about the first is a
16873
12:17:23,340 --> 12:17:24,340
multi-layer switch which operates on
16874
12:17:25,916 --> 12:17:26,916
layer 2 and 3. our usual switch because
16875
12:17:29,936 --> 12:17:30,936
it's only dealing with Mac addresses is
16876
12:17:32,460 --> 12:17:33,460
dealing with the data link layer
16877
12:17:35,700 --> 12:17:36,700
which on the OSI model
16878
12:17:38,520 --> 12:17:39,520
is Layer Two
16879
12:17:40,320 --> 12:17:41,320
a multi-layer switch is also operating
16880
12:17:43,200 --> 12:17:44,200
on layer 3. it also routes
16881
12:17:47,160 --> 12:17:48,160
so it is not just a switch it's also a
16882
12:17:50,160 --> 12:17:51,160
router a Content switch is even going
16883
12:17:52,320 --> 12:17:53,320
further up the OSI model and analyzes
16884
12:17:56,520 --> 12:17:57,520
the content
16885
12:18:00,960 --> 12:18:01,960
in a packet
16886
12:18:02,756 --> 12:18:03,756
to determine
16887
12:18:04,380 --> 12:18:05,380
where to send it
16888
12:18:06,776 --> 12:18:07,776
this is also why it's called a load
16889
12:18:10,860 --> 12:18:11,860
bearing switch because it helps reduce
16890
12:18:13,916 --> 12:18:14,916
the load on a specific node by
16891
12:18:18,416 --> 12:18:19,416
sending the data out to several
16892
12:18:20,460 --> 12:18:21,460
different devices
16893
12:18:22,380 --> 12:18:23,380
that can all deal with the same content
16894
12:18:26,700 --> 12:18:27,700
in a device
16895
12:18:28,916 --> 12:18:29,916
now we're going to talk further about
16896
12:18:31,200 --> 12:18:32,200
routing in the next lesson
16897
12:18:37,330 --> 12:18:38,330
[Music]
16898
12:18:53,276 --> 12:18:54,276
spanning tree protocol
16899
12:18:56,880 --> 12:18:57,880
so what is spanning tree
16900
12:19:00,060 --> 12:19:01,060
it's defined by the IEEE
16901
12:19:02,660 --> 12:19:03,660
802.1d standard
16902
12:19:05,276 --> 12:19:06,276
and basically it allows switches to
16903
12:19:07,140 --> 12:19:08,140
communicate in order to prevent loops on
16904
12:19:09,900 --> 12:19:10,900
our switch Network
16905
12:19:12,116 --> 12:19:13,116
it runs a mathematical algorithm
16906
12:19:15,680 --> 12:19:16,680
it finds out on blocks which ports would
16907
12:19:19,500 --> 12:19:20,500
be the possible causes of layer 2 loops
16908
12:19:24,596 --> 12:19:25,596
basically a loop will occur on our
16909
12:19:26,936 --> 12:19:27,936
switch Network when there's more than
16910
12:19:28,980 --> 12:19:29,980
one path for a frame to take
16911
12:19:31,080 --> 12:19:32,080
and this could cause obviously confusion
16912
12:19:34,160 --> 12:19:35,160
as I'll illustrate in a moment so it's a
16913
12:19:37,320 --> 12:19:38,320
real simple
16914
12:19:38,640 --> 12:19:39,640
illustration here with our diagram
16915
12:19:41,580 --> 12:19:42,580
so switch one for example will receive a
16916
12:19:44,040 --> 12:19:45,040
frame on its fast ethernet zero slash
16917
12:19:45,960 --> 12:19:46,960
one
16918
12:19:47,040 --> 12:19:48,040
and it will flood it out of its next
16919
12:19:49,616 --> 12:19:50,616
interface fast ethernet zero slash two
16920
12:19:51,776 --> 12:19:52,776
and remember if there's 24 interfaces
16921
12:19:54,180 --> 12:19:55,180
then it would be flooded in them out of
16922
12:19:56,040 --> 12:19:57,040
all 24.
16923
12:19:58,140 --> 12:19:59,140
now switch 2 would receive this
16924
12:20:01,080 --> 12:20:02,080
um and the address
16925
12:20:03,180 --> 12:20:04,180
would be for host a and it would be
16926
12:20:05,276 --> 12:20:06,276
firstly received by switch a switch one
16927
12:20:08,880 --> 12:20:09,880
and recognize that host a was connected
16928
12:20:10,916 --> 12:20:11,916
to fast ethernet 0.1 unfortunately that
16929
12:20:14,220 --> 12:20:15,220
address would come out of the bottom of
16930
12:20:16,080 --> 12:20:17,080
switch one go around and reach the
16931
12:20:18,596 --> 12:20:19,596
bottom of switch two switch two then
16932
12:20:21,300 --> 12:20:22,300
thinks that
16933
12:20:22,800 --> 12:20:23,800
it knows the way to get to host a and
16934
12:20:26,820 --> 12:20:27,820
the direction to go is through fast
16935
12:20:28,680 --> 12:20:29,680
ethernet zero slash one it will send
16936
12:20:30,900 --> 12:20:31,900
that out of fast ethernet uh sorry first
16937
12:20:33,416 --> 12:20:34,416
ethernet 0-2 and it will send that to
16938
12:20:35,880 --> 12:20:36,880
zero slash one now we have a problem in
16939
12:20:39,000 --> 12:20:40,000
that the ports on the switch all think
16940
12:20:41,640 --> 12:20:42,640
that they can release reach host a and
16941
12:20:44,520 --> 12:20:45,520
that isn't in fact the case
16942
12:20:47,936 --> 12:20:48,936
now there's no time to live field in
16943
12:20:50,160 --> 12:20:51,160
layer 2 frames so that would go around
16944
12:20:51,776 --> 12:20:52,776
around the network until every single
16945
12:20:53,880 --> 12:20:54,880
switch thinks it knows how to get to
16946
12:20:55,320 --> 12:20:56,320
host a
16947
12:20:56,460 --> 12:20:57,460
and it would bring your network to a
16948
12:20:58,560 --> 12:20:59,560
grinding halt
16949
12:20:59,936 --> 12:21:00,936
so there's a mathematical algorithm was
16950
12:21:02,936 --> 12:21:03,936
created
16951
12:21:05,820 --> 12:21:06,820
and it's based on two key components the
16952
12:21:08,220 --> 12:21:09,220
bridge ID
16953
12:21:09,720 --> 12:21:10,720
for bridge ID you can basically read
16954
12:21:11,520 --> 12:21:12,520
switch ID it's the same thing and the
16955
12:21:14,276 --> 12:21:15,276
path cost
16956
12:21:16,320 --> 12:21:17,320
so these are contained inside the frame
16957
12:21:20,400 --> 12:21:21,400
Bridge ideas and eight byte field
16958
12:21:22,140 --> 12:21:23,140
consisting of the bridge priority and
16959
12:21:24,720 --> 12:21:25,720
the MAC address the base Mac address of
16960
12:21:27,660 --> 12:21:28,660
the switch
16961
12:21:30,116 --> 12:21:31,116
the default Bridge priority is 32768
16962
12:21:34,616 --> 12:21:35,616
and then this is added to the MAC
16963
12:21:36,000 --> 12:21:37,000
address now I've issued a show version
16964
12:21:38,756 --> 12:21:39,756
on a switch and it showed the base Mac
16965
12:21:42,116 --> 12:21:43,116
address among other information and each
16966
12:21:46,020 --> 12:21:47,020
one will be different
16967
12:21:49,740 --> 12:21:50,740
so the path cost is used to calculate
16968
12:21:51,840 --> 12:21:52,840
the proximity to neighbor switches the
16969
12:21:54,900 --> 12:21:55,900
higher the bandwidth the lower the
16970
12:21:56,580 --> 12:21:57,580
default cost so we can see the 10
16971
12:21:59,096 --> 12:22:00,096
gigabit connection here has got the
16972
12:22:00,660 --> 12:22:01,660
lowest forecast allocated to it
16973
12:22:04,560 --> 12:22:05,560
so there's a four-step path selection
16974
12:22:07,500 --> 12:22:08,500
process
16975
12:22:09,660 --> 12:22:10,660
so the lowest route to bridge ID the
16976
12:22:12,660 --> 12:22:13,660
lowest path cost to the root Bridge
16977
12:22:16,200 --> 12:22:17,200
the lowest sender Bridge ID
16978
12:22:18,720 --> 12:22:19,720
and the lowest Port ID and it will go
16979
12:22:20,640 --> 12:22:21,640
through this four steps until it makes a
16980
12:22:22,380 --> 12:22:23,380
decision
16981
12:22:23,460 --> 12:22:24,460
this all happens after the exchange of
16982
12:22:25,500 --> 12:22:26,500
bridge protocol data units which are
16983
12:22:27,660 --> 12:22:28,660
called bpdus
16984
12:22:30,900 --> 12:22:31,900
so let's have a look at our diagram we
16985
12:22:33,360 --> 12:22:34,360
have three switches here and just to
16986
12:22:35,640 --> 12:22:36,640
keep things simple we've given them the
16987
12:22:37,140 --> 12:22:38,140
Mac addresses of all A's or B's and all
16988
12:22:39,300 --> 12:22:40,300
C's
16989
12:22:40,740 --> 12:22:41,740
they're all connected so we could
16990
12:22:42,300 --> 12:22:43,300
possibly have a loop here unless
16991
12:22:44,700 --> 12:22:45,700
something is done to close down one or
16992
12:22:47,340 --> 12:22:48,340
more of the ports
16993
12:22:48,900 --> 12:22:49,900
so there's a root Bridge election
16994
12:22:50,276 --> 12:22:51,276
firstly
16995
12:22:51,720 --> 12:22:52,720
then there's root Port selection
16996
12:22:54,720 --> 12:22:55,720
then there's a designated Port election
16997
12:22:58,256 --> 12:22:59,256
the bridge with the lowest Bridge ID is
16998
12:23:01,080 --> 12:23:02,080
selected as a route and remember it's a
16999
12:23:03,180 --> 12:23:04,180
combination between the priority and the
17000
12:23:05,040 --> 12:23:06,040
MAC address in this case the lowest Mac
17001
12:23:07,436 --> 12:23:08,436
address is going to be the one with all
17002
12:23:09,300 --> 12:23:10,300
of the A's because that's a lower number
17003
12:23:12,000 --> 12:23:13,000
in hexadecimal
17004
12:23:14,756 --> 12:23:15,756
so root Port is the port closest to the
17005
12:23:18,180 --> 12:23:19,180
root bridge now the route bridge will
17006
12:23:20,276 --> 12:23:21,276
not have any root ports because it is
17007
12:23:22,200 --> 12:23:23,200
the route Bridge so its ports will all
17008
12:23:24,416 --> 12:23:25,416
be known as designated ports you can see
17009
12:23:27,240 --> 12:23:28,240
switch two and three has elected its
17010
12:23:29,276 --> 12:23:30,276
closest port to the uh route Bridge as
17011
12:23:34,140 --> 12:23:35,140
fast ethernet zero slash one
17012
12:23:38,160 --> 12:23:39,160
every bridge you set the root Bridge
17013
12:23:39,720 --> 12:23:40,720
must elect the root ports and each
17014
12:23:42,240 --> 12:23:43,240
interface adds a cost
17015
12:23:44,220 --> 12:23:45,220
so as it goes as the frame goes through
17016
12:23:46,320 --> 12:23:47,320
different interfaces the cost is added
17017
12:23:50,276 --> 12:23:51,276
you can see fast ethernet 0 1 is 19. as
17018
12:23:54,540 --> 12:23:55,540
it gets to fast ethernet 0 2. that Port
17019
12:23:58,436 --> 12:23:59,436
cost is added again and 19 plus 19 costs
17020
12:24:02,220 --> 12:24:03,220
have been 19 each uh comes up as 38. so
17021
12:24:05,700 --> 12:24:06,700
fast ethernet 0 1 wins
17022
12:24:09,416 --> 12:24:10,416
the designated Port election and
17023
12:24:11,640 --> 12:24:12,640
designated report sends it receives
17024
12:24:13,020 --> 12:24:14,020
traffic on the segment to the root
17025
12:24:15,180 --> 12:24:16,180
Bridge
17026
12:24:16,020 --> 12:24:17,020
only one designated Port per segment you
17027
12:24:19,560 --> 12:24:20,560
can see there's a segment at the bottom
17028
12:24:21,060 --> 12:24:22,060
here
17029
12:24:22,256 --> 12:24:23,256
if I see Zero slash two on switch two
17030
12:24:24,596 --> 12:24:25,596
and three
17031
12:24:25,980 --> 12:24:26,980
the toy goes to the lowest root Bridge
17032
12:24:28,140 --> 12:24:29,140
ID lowest root path cost lowest sender
17033
12:24:31,500 --> 12:24:32,500
Bridge ID and lowest Port ID
17034
12:24:34,080 --> 12:24:35,080
and you can see on switch two and three
17035
12:24:35,756 --> 12:24:36,756
the lowest out of the two would be the
17036
12:24:37,500 --> 12:24:38,500
switch with the number MAC address bb bb
17037
12:24:40,980 --> 12:24:41,980
and so on
17038
12:24:42,540 --> 12:24:43,540
the port States for STP can only be one
17039
12:24:45,300 --> 12:24:46,300
of the five following it's forwarding
17040
12:24:47,340 --> 12:24:48,340
it's learning it's listening blocking or
17041
12:24:50,756 --> 12:24:51,756
disabled
17042
12:24:52,500 --> 12:24:53,500
all right so we've covered a fair bit
17043
12:24:54,180 --> 12:24:55,180
there I only wanted to give you a taster
17044
12:24:55,860 --> 12:24:56,860
STP and um there could be a lab on this
17045
12:24:59,520 --> 12:25:00,520
I haven't decided yet obviously you'll
17046
12:25:01,980 --> 12:25:02,980
be digging into a lot more detail when
17047
12:25:03,360 --> 12:25:04,360
you actually come to do the CCNA thanks
17048
12:25:05,820 --> 12:25:06,820
for listening
17049
12:25:09,630 --> 12:25:10,630
[Music]
17050
12:25:25,680 --> 12:25:26,680
welcome to modulate lesson 2B power over
17051
12:25:28,980 --> 12:25:29,980
ethernet
17052
12:25:30,960 --> 12:25:31,960
or Poe
17053
12:25:32,936 --> 12:25:33,936
what is poe the benefits components
17054
12:25:37,380 --> 12:25:38,380
the power supply equipment we love our
17055
12:25:40,020 --> 12:25:41,020
abbreviations there PSE
17056
12:25:42,180 --> 12:25:43,180
n-span mid span
17057
12:25:44,880 --> 12:25:45,880
power devices
17058
12:25:46,800 --> 12:25:47,800
modes in Poe standards how does it work
17059
12:25:52,256 --> 12:25:53,256
what is it first
17060
12:25:54,000 --> 12:25:55,000
Poe is a technology that allows a um a
17061
12:25:57,360 --> 12:25:58,360
device connected to an ethernet cable to
17062
12:25:59,520 --> 12:26:00,520
receive the following electrical power
17063
12:26:02,040 --> 12:26:03,040
and data
17064
12:26:03,776 --> 12:26:04,776
now obviously a device connected to an
17065
12:26:06,840 --> 12:26:07,840
ether cable was already going to be
17066
12:26:08,700 --> 12:26:09,700
receiving data because that's what um
17067
12:26:10,916 --> 12:26:11,916
ethernet was designed for
17068
12:26:12,960 --> 12:26:13,960
however what it wasn't initially
17069
12:26:15,000 --> 12:26:16,000
designed for and some very clever people
17070
12:26:16,990 --> 12:26:17,990
[Music]
17071
12:26:18,180 --> 12:26:19,180
um found or realized away and tested it
17072
12:26:21,596 --> 12:26:22,596
is to deliver power
17073
12:26:23,640 --> 12:26:24,640
and it's got all sorts of uses we're
17074
12:26:26,040 --> 12:26:27,040
talking in the context of networking
17075
12:26:28,500 --> 12:26:29,500
however I recently bought a guitar
17076
12:26:31,380 --> 12:26:32,380
effects board that plugs into the back
17077
12:26:34,256 --> 12:26:35,256
of my amp using a ethernet cable and I
17078
12:26:38,220 --> 12:26:39,220
thought it was going to come with a
17079
12:26:39,300 --> 12:26:40,300
power supply but as soon as I plug the
17080
12:26:40,916 --> 12:26:41,916
ethernet cable in it actually powered up
17081
12:26:43,080 --> 12:26:44,080
the pedalboard
17082
12:26:44,340 --> 12:26:45,340
and the pedal board offers a whole bunch
17083
12:26:46,200 --> 12:26:47,200
of effects you can record about five
17084
12:26:49,020 --> 12:26:50,020
minutes of Music Loop it add other
17085
12:26:51,776 --> 12:26:52,776
tracks onto that Loop and a whole bunch
17086
12:26:54,116 --> 12:26:55,116
of stuff so um very clever technology
17087
12:26:57,116 --> 12:26:58,116
and it's got a multitude of purposes
17088
12:26:59,756 --> 12:27:00,756
and it's just one of those things when
17089
12:27:01,200 --> 12:27:02,200
it's invented you think why didn't
17090
12:27:02,640 --> 12:27:03,640
somebody think of that earlier
17091
12:27:05,640 --> 12:27:06,640
the power devices that support Poe only
17092
12:27:07,916 --> 12:27:08,916
operate from the piracies through the
17093
12:27:09,776 --> 12:27:10,776
ethernet cable obviously there's a
17094
12:27:11,756 --> 12:27:12,756
finite amount of charge or power that
17095
12:27:15,116 --> 12:27:16,116
you can push through the cable because
17096
12:27:17,520 --> 12:27:18,520
it's quite a thin strand of metal
17097
12:27:19,980 --> 12:27:20,980
but um obviously avoid the need for
17098
12:27:22,800 --> 12:27:23,800
additional electrical wiring are you
17099
12:27:25,380 --> 12:27:26,380
your power supply unit and all the wires
17100
12:27:27,720 --> 12:27:28,720
that come with that and as we all know
17101
12:27:29,640 --> 12:27:30,640
every single power device has got a
17102
12:27:31,436 --> 12:27:32,436
different
17103
12:27:32,276 --> 12:27:33,276
and socket a jack on it and it just
17104
12:27:34,616 --> 12:27:35,616
makes it very awkward to keep a track of
17105
12:27:36,416 --> 12:27:37,416
which is which and then obviously your
17106
12:27:38,640 --> 12:27:39,640
power supply can die making our lives a
17107
12:27:41,276 --> 12:27:42,276
misery
17108
12:27:42,776 --> 12:27:43,776
so what is it we're supplying electrical
17109
12:27:44,520 --> 12:27:45,520
power through the electrical ethernet
17110
12:27:46,320 --> 12:27:47,320
cable in order to power devices I know
17111
12:27:48,360 --> 12:27:49,360
I'm stating the obvious here
17112
12:27:50,880 --> 12:27:51,880
and of course is uh designed for
17113
12:27:52,980 --> 12:27:53,980
beginners as well very handy for voice
17114
12:27:55,380 --> 12:27:56,380
over IP uh telephony very useful indeed
17115
12:27:58,800 --> 12:27:59,800
because it just um saves those extra
17116
12:28:00,900 --> 12:28:01,900
wires and cables
17117
12:28:03,000 --> 12:28:04,000
wireless access points network cameras
17118
12:28:05,880 --> 12:28:06,880
um very big in the field of security
17119
12:28:07,320 --> 12:28:08,320
especially industrial security and shops
17120
12:28:09,776 --> 12:28:10,776
and warehouses
17121
12:28:12,660 --> 12:28:13,660
since the devices can consume the
17122
12:28:14,580 --> 12:28:15,580
required power from the ethernet cable
17123
12:28:16,020 --> 12:28:17,020
there's no need for the separate local
17124
12:28:18,416 --> 12:28:19,416
power supply
17125
12:28:20,040 --> 12:28:21,040
if the device is an outdoor wireless
17126
12:28:21,840 --> 12:28:22,840
access point or a WAP it supports then
17127
12:28:24,900 --> 12:28:25,900
we can do the following we can send it
17128
12:28:26,700 --> 12:28:27,700
electrical power and we can send data
17129
12:28:28,860 --> 12:28:29,860
through the cable
17130
12:28:30,540 --> 12:28:31,540
eliminates the local power source
17131
12:28:33,300 --> 12:28:34,300
it's saving you money no great no need
17132
12:28:36,000 --> 12:28:37,000
to upgrade the existing CAT5 or coccyx
17133
12:28:38,640 --> 12:28:39,640
cabling which is another Lifesaver and a
17134
12:28:41,276 --> 12:28:42,276
wallet saver for companies no need to
17135
12:28:43,800 --> 12:28:44,800
purchase the power outlets electrical
17136
12:28:45,900 --> 12:28:46,900
wiring
17137
12:28:48,060 --> 12:28:49,060
I'm not sure if I'd talk about that in a
17138
12:28:49,916 --> 12:28:50,916
moment as well but it's just another
17139
12:28:51,300 --> 12:28:52,300
thing uh that that wouldn't possibly go
17140
12:28:54,240 --> 12:28:55,240
wrong I can't remember if I've put this
17141
12:28:55,740 --> 12:28:56,740
in a slide somewhere so you've got one
17142
12:28:58,020 --> 12:28:59,020
less
17143
12:28:58,916 --> 12:28:59,916
um point of failure there
17144
12:29:03,116 --> 12:29:04,116
very easy to install basically you just
17145
12:29:05,640 --> 12:29:06,640
plug it plug and play you can install it
17146
12:29:08,160 --> 12:29:09,160
even though locations that are hard to
17147
12:29:09,540 --> 12:29:10,540
reach because there's no need for local
17148
12:29:11,160 --> 12:29:12,160
power
17149
12:29:13,200 --> 12:29:14,200
increase reliability
17150
12:29:15,660 --> 12:29:16,660
um less risk of power interruptions
17151
12:29:17,640 --> 12:29:18,640
caused by human interference because the
17152
12:29:21,116 --> 12:29:22,116
device is essentially powered a lot of
17153
12:29:23,276 --> 12:29:24,276
the time our networking equipment has a
17154
12:29:25,320 --> 12:29:26,320
redundant power supplies as well and
17155
12:29:27,000 --> 12:29:28,000
backup generators especially if it's an
17156
12:29:29,220 --> 12:29:30,220
ISP
17157
12:29:30,480 --> 12:29:31,480
so they'll keep working
17158
12:29:32,460 --> 12:29:33,460
enhanced Operational Support and
17159
12:29:35,040 --> 12:29:36,040
monitoring and Remote Management we can
17160
12:29:36,840 --> 12:29:37,840
do through SNMP so we can power the
17161
12:29:39,300 --> 12:29:40,300
devices and perform different operations
17162
12:29:41,880 --> 12:29:42,880
over the network
17163
12:29:43,916 --> 12:29:44,916
very handy I know I could remotely
17164
12:29:46,080 --> 12:29:47,080
reboot different devices on my remote
17165
12:29:49,500 --> 12:29:50,500
rack
17166
12:29:51,300 --> 12:29:52,300
um if I couldn't reach it and I didn't
17167
12:29:52,860 --> 12:29:53,860
want to pay a tech to go and power cycle
17168
12:29:54,660 --> 12:29:55,660
stuff I could just send a message for
17169
12:29:57,660 --> 12:29:58,660
the power unit to reboot if it needed to
17170
12:30:02,160 --> 12:30:03,160
all right two basic components your
17171
12:30:04,140 --> 12:30:05,140
power supply equipment and your powered
17172
12:30:06,300 --> 12:30:07,300
device
17173
12:30:07,500 --> 12:30:08,500
your PSE is the a unit that adds
17174
12:30:10,980 --> 12:30:11,980
electrical power to the ethernet cable
17175
12:30:13,140 --> 12:30:14,140
you've got n Span and mid span
17176
12:30:16,380 --> 12:30:17,380
the end span is it refers to a switch
17177
12:30:18,240 --> 12:30:19,240
that supports Poe in addition to its
17178
12:30:21,000 --> 12:30:22,000
switching role so we can do both these
17179
12:30:23,880 --> 12:30:24,880
switches are capable of sending
17180
12:30:25,680 --> 12:30:26,680
electrical power and data to the device
17181
12:30:29,640 --> 12:30:30,640
mid-span refers to a standalone inline
17182
12:30:32,040 --> 12:30:33,040
injector that provides power to the
17183
12:30:34,020 --> 12:30:35,020
Ethernet cable so it's not built into a
17184
12:30:36,240 --> 12:30:37,240
switch
17185
12:30:37,080 --> 12:30:38,080
this is a situations where a switch
17186
12:30:38,880 --> 12:30:39,880
doesn't have the built-in Poe it could
17187
12:30:41,640 --> 12:30:42,640
be an older model or a cheaper model for
17188
12:30:43,380 --> 12:30:44,380
whatever reason
17189
12:30:45,300 --> 12:30:46,300
so you can pass the data coming from the
17190
12:30:47,400 --> 12:30:48,400
switch to the inline injector and can
17191
12:30:50,460 --> 12:30:51,460
output the same data but it adds power
17192
12:30:52,740 --> 12:30:53,740
to the um
17193
12:30:54,840 --> 12:30:55,840
points of the cable there
17194
12:30:57,300 --> 12:30:58,300
the power device supports Poe receives
17195
12:31:00,000 --> 12:31:01,000
the power via an ethernet cable
17196
12:31:03,180 --> 12:31:04,180
now in Poe there's two different modes
17197
12:31:05,936 --> 12:31:06,936
for combining the following data and
17198
12:31:08,700 --> 12:31:09,700
power of the ethernet cable the two
17199
12:31:11,040 --> 12:31:12,040
modes are not very imaginative
17200
12:31:13,320 --> 12:31:14,320
unfortunately mode a and mode B
17201
12:31:16,320 --> 12:31:17,320
suppose it could have been one or two or
17202
12:31:18,416 --> 12:31:19,416
Jack and Jill
17203
12:31:19,916 --> 12:31:20,916
mode a the electrical power and the data
17204
12:31:22,320 --> 12:31:23,320
are combined on the same wires over the
17205
12:31:24,180 --> 12:31:25,180
ethernet cable
17206
12:31:25,500 --> 12:31:26,500
this is called Phantom powering
17207
12:31:28,560 --> 12:31:29,560
mode B the electrical power and data are
17208
12:31:30,840 --> 12:31:31,840
carried on different wires which is more
17209
12:31:32,700 --> 12:31:33,700
common
17210
12:31:34,320 --> 12:31:35,320
separate the data and power inside the
17211
12:31:36,240 --> 12:31:37,240
ethernet cable
17212
12:31:38,580 --> 12:31:39,580
so in the internet cable if you've got a
17213
12:31:41,160 --> 12:31:42,160
pair of wires carried only the power
17214
12:31:42,720 --> 12:31:43,720
then the other pair of wires would carry
17215
12:31:44,820 --> 12:31:45,820
only the data
17216
12:31:47,756 --> 12:31:48,756
uh First International standard was
17217
12:31:49,820 --> 12:31:50,820
802.3 AF
17218
12:31:51,960 --> 12:31:52,960
ratified a long time ago June 2003 and
17219
12:31:55,860 --> 12:31:56,860
it defines um a power supply of up to
17220
12:31:58,680 --> 12:31:59,680
1.54 watts of DC
17221
12:32:03,480 --> 12:32:04,480
uses 48 volts
17222
12:32:05,820 --> 12:32:06,820
as growing demand for more power over
17223
12:32:07,800 --> 12:32:08,800
Ethernet cable so the standard was
17224
12:32:09,416 --> 12:32:10,416
updated and 802.3
17225
12:32:14,660 --> 12:32:15,660
Poe Plus
17226
12:32:16,800 --> 12:32:17,800
this was adopted back in 2009
17227
12:32:20,040 --> 12:32:21,040
and it defines the following a power
17228
12:32:21,840 --> 12:32:22,840
supply of up to 34.2 watts of DC power
17229
12:32:24,720 --> 12:32:25,720
using 48 volts
17230
12:32:27,540 --> 12:32:28,540
both the I um IEEE 802.3 AF and 80 are
17231
12:32:33,180 --> 12:32:34,180
now included in the ethernet standards
17232
12:32:35,160 --> 12:32:36,160
they've all been combined together
17233
12:32:37,980 --> 12:32:38,980
as we know from earlier presentations
17234
12:32:40,320 --> 12:32:41,320
the ethernet cable has four
17235
12:32:42,980 --> 12:32:43,980
pairs of Twisted wire
17236
12:32:45,360 --> 12:32:46,360
this is cart 5e and Cat6
17237
12:32:49,080 --> 12:32:50,080
uh for and we already covered earlier
17238
12:32:52,320 --> 12:32:53,320
that 10 base T and about um 100 base T
17239
12:32:55,400 --> 12:32:56,400
ethernet only use uh two pairs of wire
17240
12:32:58,916 --> 12:32:59,916
to send the data so this leaves us some
17241
12:33:01,560 --> 12:33:02,560
spare wires two pairs of spare wires
17242
12:33:04,740 --> 12:33:05,740
so electrical current flows in the loop
17243
12:33:07,020 --> 12:33:08,020
powering the electrical components such
17244
12:33:08,520 --> 12:33:09,520
as bulbs and fans the loop is an
17245
12:33:11,096 --> 12:33:12,096
electrical circuit
17246
12:33:14,160 --> 12:33:15,160
and since the electrical current flows
17247
12:33:15,900 --> 12:33:16,900
in the loop we need two conductors to
17248
12:33:17,460 --> 12:33:18,460
deliver power over an ethernet cable
17249
12:33:21,540 --> 12:33:22,540
uh typically we use 48 volts that says
17250
12:33:24,480 --> 12:33:25,480
sufficient power to transfer over the
17251
12:33:26,096 --> 12:33:27,096
cable and it's safe for users so it's
17252
12:33:28,256 --> 12:33:29,256
not going to injure anyone
17253
12:33:31,740 --> 12:33:32,740
now if you plug a Poe device into one
17254
12:33:36,240 --> 12:33:37,240
that isn't designed for use with Poe
17255
12:33:38,096 --> 12:33:39,096
then you could cause damage and fry it
17256
12:33:41,340 --> 12:33:42,340
and
17257
12:33:42,116 --> 12:33:43,116
in other words
17258
12:33:44,096 --> 12:33:45,096
and the PSE sends a lower voltage to a
17259
12:33:46,500 --> 12:33:47,500
device to detect the characteristic
17260
12:33:48,360 --> 12:33:49,360
signature of a compatible PD
17261
12:33:51,480 --> 12:33:52,480
if he takes a signature then it knows
17262
12:33:53,640 --> 12:33:54,640
the 48 volts can be applied
17263
12:33:55,980 --> 12:33:56,980
the PD lets the PSE know how much power
17264
12:33:58,256 --> 12:33:59,256
it requires to operate so this is to
17265
12:34:00,900 --> 12:34:01,900
save a surge basically on the
17266
12:34:03,116 --> 12:34:04,116
um line now too much power has been sent
17267
12:34:06,116 --> 12:34:07,116
the requirement of power is classified
17268
12:34:08,460 --> 12:34:09,460
in the power classes shown below
17269
12:34:11,160 --> 12:34:12,160
probably worth making a note of these
17270
12:34:12,840 --> 12:34:13,840
write them down just in case it comes up
17271
12:34:15,116 --> 12:34:16,116
in the exam
17272
12:34:20,756 --> 12:34:21,756
difference between the following power
17273
12:34:22,500 --> 12:34:23,500
supplied by the PSE power received by
17274
12:34:25,740 --> 12:34:26,740
the PD account for lostpower
17275
12:34:28,916 --> 12:34:29,916
now there is a maximum distance which
17276
12:34:31,020 --> 12:34:32,020
matches in with the ethernet standards
17277
12:34:33,060 --> 12:34:34,060
and maximum support distance is 100
17278
12:34:35,460 --> 12:34:36,460
meters
17279
12:34:38,756 --> 12:34:39,756
there's a new standard which increases
17280
12:34:40,740 --> 12:34:41,740
the power available and uses a wide
17281
12:34:44,220 --> 12:34:45,220
range of the following devices Thin
17282
12:34:46,500 --> 12:34:47,500
Client Terminals and pointer sales stuff
17283
12:34:49,436 --> 12:34:50,436
in shops
17284
12:34:51,480 --> 12:34:52,480
video conferencing
17285
12:34:54,596 --> 12:34:55,596
so I think that's all we need to know
17286
12:34:56,040 --> 12:34:57,040
we've covered Poe the benefits the
17287
12:34:58,680 --> 12:34:59,680
components the PSE end span mid-span the
17288
12:35:03,776 --> 12:35:04,776
power device the the modes for Poe
17289
12:35:07,800 --> 12:35:08,800
which is a and b uh the standards and
17290
12:35:10,860 --> 12:35:11,860
how does it work so that's all for now
17291
12:35:13,140 --> 12:35:14,140
thanks for watching
17292
12:35:19,100 --> 12:35:20,100
[Music]
17293
12:35:41,220 --> 12:35:42,220
local area Networks routing
17294
12:35:45,720 --> 12:35:46,720
so in the previous module we discussed
17295
12:35:48,180 --> 12:35:49,180
switches and as you remember they're
17296
12:35:50,276 --> 12:35:51,276
very important for the functionality of
17297
12:35:52,916 --> 12:35:53,916
a local area network
17298
12:35:55,680 --> 12:35:56,680
now when we talk about connecting
17299
12:35:58,080 --> 12:35:59,080
several different local area networks
17300
12:36:00,840 --> 12:36:01,840
together through
17301
12:36:02,640 --> 12:36:03,640
the internet we have to deal with how a
17302
12:36:06,060 --> 12:36:07,060
switch which again
17303
12:36:08,160 --> 12:36:09,160
is based on Mac addresses the physical
17304
12:36:11,040 --> 12:36:12,040
address on a computer
17305
12:36:12,800 --> 12:36:13,800
can find the MAC address of a computer
17306
12:36:16,340 --> 12:36:17,340
halfway across
17307
12:36:18,300 --> 12:36:19,300
the world
17308
12:36:20,096 --> 12:36:21,096
and the way it does this is by assigning
17309
12:36:22,380 --> 12:36:23,380
each Mac address uh an IP address
17310
12:36:26,040 --> 12:36:27,040
now when we start dealing with IP
17311
12:36:27,416 --> 12:36:28,416
address we deal with a completely
17312
12:36:28,980 --> 12:36:29,980
different type of device one which is
17313
12:36:31,616 --> 12:36:32,616
called routing and the process of
17314
12:36:33,776 --> 12:36:34,776
routing is what really allows the
17315
12:36:35,700 --> 12:36:36,700
internet to work and so in this module
17316
12:36:38,820 --> 12:36:39,820
we're going to talk more about the
17317
12:36:40,436 --> 12:36:41,436
devices that allow routing to work
17318
12:36:42,540 --> 12:36:43,540
called routers
17319
12:36:44,580 --> 12:36:45,580
so first of all we're going to Define
17320
12:36:46,800 --> 12:36:47,800
what a router is and then we're going to
17321
12:36:49,980 --> 12:36:50,980
talk about how it functions which is
17322
12:36:52,436 --> 12:36:53,436
also called routing
17323
12:36:56,460 --> 12:36:57,460
then we're going to identify something
17324
12:36:58,980 --> 12:36:59,980
called static routing just like we've
17325
12:37:02,040 --> 12:37:03,040
talked about dynamic
17326
12:37:05,520 --> 12:37:06,520
versus static IP addresses
17327
12:37:10,140 --> 12:37:11,140
we also have
17328
12:37:11,820 --> 12:37:12,820
Dynamic and static routing obviously one
17329
12:37:15,116 --> 12:37:16,116
is more resilient than the other but
17330
12:37:17,936 --> 12:37:18,936
there are certain instances in which we
17331
12:37:19,500 --> 12:37:20,500
want to always go to the same location
17332
12:37:21,900 --> 12:37:22,900
and that's why we're going to have
17333
12:37:23,400 --> 12:37:24,400
static routing then we need to cover
17334
12:37:25,380 --> 12:37:26,380
some terms that you might see when
17335
12:37:27,960 --> 12:37:28,960
you're dealing with routing these terms
17336
12:37:29,756 --> 12:37:30,756
are hop counts
17337
12:37:32,000 --> 12:37:33,000
costs
17338
12:37:33,596 --> 12:37:34,596
latency
17339
12:37:35,160 --> 12:37:36,160
and convergence so we're going to cover
17340
12:37:37,436 --> 12:37:38,436
all those terms so you have a good idea
17341
12:37:39,300 --> 12:37:40,300
in case you see them on the exam what
17342
12:37:40,800 --> 12:37:41,800
they're referring to
17343
12:37:42,116 --> 12:37:43,116
so a router is essentially like an
17344
12:37:45,360 --> 12:37:46,360
extension cable an extension cable
17345
12:37:47,580 --> 12:37:48,580
connects two sources of power and in
17346
12:37:49,680 --> 12:37:50,680
this case a router connects to networks
17347
12:37:52,560 --> 12:37:53,560
together in order to make a larger
17348
12:37:54,540 --> 12:37:55,540
Network
17349
12:37:55,680 --> 12:37:56,680
in networking the router is used to
17350
12:37:57,540 --> 12:37:58,540
connect two networks together and give a
17351
12:38:00,060 --> 12:38:01,060
clear route for data to travel between
17352
12:38:02,840 --> 12:38:03,840
these two devices now in smaller
17353
12:38:05,936 --> 12:38:06,936
settings such as houses or a small
17354
12:38:09,660 --> 12:38:10,660
office home office or Soho
17355
12:38:13,080 --> 12:38:14,080
the router connects the device is to the
17356
12:38:15,960 --> 12:38:16,960
Internet so for instance you have uh
17357
12:38:19,320 --> 12:38:20,320
your computer and you have a laptop and
17358
12:38:22,256 --> 12:38:23,256
perhaps you have some sort of Apple TV
17359
12:38:24,300 --> 12:38:25,300
device or some device that's connecting
17360
12:38:26,520 --> 12:38:27,520
to your TV and the internet and all of
17361
12:38:28,140 --> 12:38:29,140
these connect through what you call your
17362
12:38:30,180 --> 12:38:31,180
router
17363
12:38:31,380 --> 12:38:32,380
now this Soho router is actually doing
17364
12:38:33,960 --> 12:38:34,960
several things it's not just a router
17365
12:38:36,660 --> 12:38:37,660
but one of the things that it does is it
17366
12:38:39,416 --> 12:38:40,416
allows you to connect all of these
17367
12:38:41,820 --> 12:38:42,820
devices in your internal Network
17368
12:38:44,660 --> 12:38:45,660
otherwise known as your Lan out to the
17369
12:38:48,660 --> 12:38:49,660
large Wan or wide area network that
17370
12:38:51,540 --> 12:38:52,540
exists in the world this is called the
17371
12:38:54,660 --> 12:38:55,660
internet
17372
12:38:57,596 --> 12:38:58,596
so in a larger scale environment the
17373
12:39:00,900 --> 12:39:01,900
routers are used to make bigger Network
17374
12:39:03,180 --> 12:39:04,180
pieces so if you can imagine that
17375
12:39:05,220 --> 12:39:06,220
instead of just having my own home I
17376
12:39:07,680 --> 12:39:08,680
have say a number of buildings across a
17377
12:39:10,616 --> 12:39:11,616
city or a number of buildings across the
17378
12:39:13,500 --> 12:39:14,500
world and I want them all to talk to one
17379
12:39:15,900 --> 12:39:16,900
another and be able to locate one
17380
12:39:17,936 --> 12:39:18,936
another as though they're sitting right
17381
12:39:19,436 --> 12:39:20,436
next to each other this is where routers
17382
12:39:21,480 --> 12:39:22,480
are going to come into play
17383
12:39:23,096 --> 12:39:24,096
this is also why routers do a lot more
17384
12:39:25,560 --> 12:39:26,560
and are more expensive than switches
17385
12:39:28,020 --> 12:39:29,020
it's also why we need fewer of them
17386
12:39:30,900 --> 12:39:31,900
now in modern networking the router is
17387
12:39:35,160 --> 12:39:36,160
either going to be a dedicated device or
17388
12:39:38,340 --> 12:39:39,340
it could be a server
17389
12:39:41,160 --> 12:39:42,160
with a routing functionality
17390
12:39:44,160 --> 12:39:45,160
meaning it's a large computer with two
17391
12:39:48,116 --> 12:39:49,116
or more network cards or Nicks in it so
17392
12:39:51,300 --> 12:39:52,300
that you can have traffic going in and
17393
12:39:54,660 --> 12:39:55,660
then traffic going out
17394
12:39:56,880 --> 12:39:57,880
now when a router receives a packet of
17395
12:40:00,480 --> 12:40:01,480
data from a client device it reads the
17396
12:40:03,000 --> 12:40:04,000
information in the packets header and
17397
12:40:06,480 --> 12:40:07,480
determines what the destination of the
17398
12:40:08,096 --> 12:40:09,096
packet is after it finds out what the
17399
12:40:10,860 --> 12:40:11,860
destination address is it looks at a
17400
12:40:13,860 --> 12:40:14,860
routing table
17401
12:40:16,080 --> 12:40:17,080
in the router in order to determine
17402
12:40:19,040 --> 12:40:20,040
where the packet is going to go in its
17403
12:40:22,200 --> 12:40:23,200
next route so for instance let's say
17404
12:40:24,900 --> 12:40:25,900
this PC here which for sake of ease
17405
12:40:27,776 --> 12:40:28,776
we'll call pc1 wants to talk to PC2
17406
12:40:31,436 --> 12:40:32,436
now it has an IP address in mind and so
17407
12:40:34,380 --> 12:40:35,380
what it does is it goes perhaps through
17408
12:40:36,960 --> 12:40:37,960
a switch but eventually to the router at
17409
12:40:39,416 --> 12:40:40,416
the end of its LAN
17410
12:40:43,020 --> 12:40:44,020
and it says hey I'm looking for this
17411
12:40:45,360 --> 12:40:46,360
specific PC now this router has what's
17412
12:40:48,300 --> 12:40:49,300
called a routing table which sometimes
17413
12:40:51,116 --> 12:40:52,116
we're going to call an ARP table because
17414
12:40:53,276 --> 12:40:54,276
ARP again the address resolution
17415
12:40:55,680 --> 12:40:56,680
protocol is what allows routing to occur
17416
12:40:58,680 --> 12:40:59,680
it's this protocol that we've talked
17417
12:41:00,960 --> 12:41:01,960
about which allows for a table that
17418
12:41:03,180 --> 12:41:04,180
would say for instance one goes to IP
17419
12:41:06,480 --> 12:41:07,480
address 192 whatever whatever Etc
17420
12:41:09,776 --> 12:41:10,776
and so this router would look for this
17421
12:41:13,860 --> 12:41:14,860
information if it doesn't know it it's
17422
12:41:16,320 --> 12:41:17,320
going to say I don't know it but I'm
17423
12:41:17,520 --> 12:41:18,520
going to go to the next router that
17424
12:41:19,140 --> 12:41:20,140
might goes to this router and the second
17425
12:41:22,200 --> 12:41:23,200
router says oh yeah I know where that
17426
12:41:24,360 --> 12:41:25,360
computer is
17427
12:41:25,860 --> 12:41:26,860
and then can forward the packet onto the
17428
12:41:28,500 --> 12:41:29,500
computer
17429
12:41:29,820 --> 12:41:30,820
it also tells this router the first one
17430
12:41:32,936 --> 12:41:33,936
which we'll call let's say router a and
17431
12:41:35,756 --> 12:41:36,756
router B
17432
12:41:37,080 --> 12:41:38,080
where that destination was so it can add
17433
12:41:39,540 --> 12:41:40,540
it to its ARP or routing table
17434
12:41:43,680 --> 12:41:44,680
and if you imagine this is only what we
17435
12:41:46,140 --> 12:41:47,140
call one hop
17436
12:41:48,540 --> 12:41:49,540
because there is one hop between these
17437
12:41:52,860 --> 12:41:53,860
two routers but you can imagine in the
17438
12:41:54,840 --> 12:41:55,840
entire world if I'm traveling from say
17439
12:41:57,680 --> 12:41:58,680
here in New York City all the way to
17440
12:42:00,596 --> 12:42:01,596
Australia for instance I might have to
17441
12:42:02,460 --> 12:42:03,460
take several different Hops and also if
17442
12:42:04,860 --> 12:42:05,860
you imagine there are probably many
17443
12:42:06,416 --> 12:42:07,416
different routes that I can take to get
17444
12:42:09,180 --> 12:42:10,180
to a specific computer
17445
12:42:11,160 --> 12:42:12,160
if we imagine
17446
12:42:13,380 --> 12:42:14,380
that the circles are the two computers
17447
12:42:17,460 --> 12:42:18,460
and the squares are the different types
17448
12:42:21,960 --> 12:42:22,960
of routers and we have them connected
17449
12:42:31,800 --> 12:42:32,800
like so
17450
12:42:33,660 --> 12:42:34,660
well there are a lot of different routes
17451
12:42:35,160 --> 12:42:36,160
that a packet can take to get from point
17452
12:42:37,500 --> 12:42:38,500
A
17453
12:42:38,276 --> 12:42:39,276
to point B and so we were allowed on WE
17454
12:42:41,220 --> 12:42:42,220
rely rather on routers to tell us which
17455
12:42:43,860 --> 12:42:44,860
path it's going to take it could take
17456
12:42:45,720 --> 12:42:46,720
this path
17457
12:42:48,000 --> 12:42:49,000
or it could take
17458
12:42:52,980 --> 12:42:53,980
this path and so on and so forth and so
17459
12:42:56,400 --> 12:42:57,400
uh depending on the number of hops and a
17460
12:42:59,276 --> 12:43:00,276
number of other things we'll talk about
17461
12:43:00,360 --> 12:43:01,360
in just a minute it'll determine where
17462
12:43:02,580 --> 12:43:03,580
the packet needs to go in order to get
17463
12:43:04,200 --> 12:43:05,200
from point A to point B some other
17464
12:43:06,240 --> 12:43:07,240
things it's going to determine too or
17465
12:43:07,560 --> 12:43:08,560
what if there's a cut in the line well
17466
12:43:09,480 --> 12:43:10,480
now it can't get here
17467
12:43:11,820 --> 12:43:12,820
and so instead it'll say well let's try
17468
12:43:13,320 --> 12:43:14,320
one of our alternate routes as well
17469
12:43:16,200 --> 12:43:17,200
now in the previous slide I talked about
17470
12:43:18,360 --> 12:43:19,360
how routers might talk to one another in
17471
12:43:21,116 --> 12:43:22,116
order to automatically update their
17472
12:43:23,096 --> 12:43:24,096
routing tables this way two routers
17473
12:43:26,580 --> 12:43:27,580
always know how to communicate with each
17474
12:43:28,500 --> 12:43:29,500
other or one computer on one side of the
17475
12:43:30,960 --> 12:43:31,960
world can always get routed or the
17476
12:43:33,360 --> 12:43:34,360
information sent from one computer on
17477
12:43:34,916 --> 12:43:35,916
one side of the world can always get
17478
12:43:35,936 --> 12:43:36,936
routed to the information on another
17479
12:43:37,560 --> 12:43:38,560
side of the world
17480
12:43:38,820 --> 12:43:39,820
but in some instances we want to tell a
17481
12:43:42,596 --> 12:43:43,596
router exactly where to send information
17482
12:43:44,776 --> 12:43:45,776
destined for a specific Network now it
17483
12:43:47,936 --> 12:43:48,936
might not always be the most practical
17484
12:43:49,320 --> 12:43:50,320
way but sometimes it's necessary so
17485
12:43:52,080 --> 12:43:53,080
static routing is when a routes and
17486
12:43:55,320 --> 12:43:56,320
routing information are entered into
17487
12:43:57,900 --> 12:43:58,900
routing tables manually and this can be
17488
12:44:00,660 --> 12:44:01,660
time consuming and because it's prone to
17489
12:44:03,360 --> 12:44:04,360
human error it can be error written and
17490
12:44:06,660 --> 12:44:07,660
can cause some problems so this is why
17491
12:44:08,700 --> 12:44:09,700
it's only done on very small systems or
17492
12:44:11,756 --> 12:44:12,756
on ones that are very internal and
17493
12:44:13,560 --> 12:44:14,560
controlled
17494
12:44:14,820 --> 12:44:15,820
now in order to statically add a route
17495
12:44:17,820 --> 12:44:18,820
we're usually going to use something
17496
12:44:19,500 --> 12:44:20,500
called the route add command now this is
17497
12:44:22,616 --> 12:44:23,616
the sort of thing you might use if you
17498
12:44:24,240 --> 12:44:25,240
were adding a route to a Cisco router or
17499
12:44:27,776 --> 12:44:28,776
to a Windows machine for instance that
17500
12:44:30,180 --> 12:44:31,180
was acting as a router or even a Windows
17501
12:44:32,160 --> 12:44:33,160
machine that's at the edge of a network
17502
12:44:33,596 --> 12:44:34,596
and needs to go out to another the way
17503
12:44:36,116 --> 12:44:37,116
it works is we use the route add command
17504
12:44:39,900 --> 12:44:40,900
with the network name
17505
12:44:44,520 --> 12:44:45,520
The Mask or the subnet mask
17506
12:44:48,800 --> 12:44:49,800
and the IP address of the Gateway
17507
12:44:53,756 --> 12:44:54,756
so this tells us if we want to get to
17508
12:44:57,116 --> 12:44:58,116
the network 192.168.2.1
17509
12:45:01,140 --> 12:45:02,140
we need to go to the subnet mask
17510
12:45:03,416 --> 12:45:04,416
255.255.0
17511
12:45:06,416 --> 12:45:07,416
and the Gateway
17512
12:45:09,860 --> 12:45:10,860
192.168.2.4 now all this information
17513
12:45:12,180 --> 12:45:13,180
would automatically be done uh
17514
12:45:15,360 --> 12:45:16,360
dynamically by most routers but in some
17515
12:45:17,580 --> 12:45:18,580
cases we're going to want to add it or
17516
12:45:19,860 --> 12:45:20,860
statically now this isn't something of
17517
12:45:21,660 --> 12:45:22,660
necessarily seen come up on the network
17518
12:45:23,580 --> 12:45:24,580
plus exam but I did want to clarify it
17519
12:45:26,220 --> 12:45:27,220
and go over it just briefly in case you
17520
12:45:28,560 --> 12:45:29,560
ever saw it in the field since this
17521
12:45:30,416 --> 12:45:31,416
might be something to do something that
17522
12:45:32,220 --> 12:45:33,220
your administrator or your boss asks you
17523
12:45:34,860 --> 12:45:35,860
to do for whatever reason or maybe
17524
12:45:36,240 --> 12:45:37,240
something you want to play around with
17525
12:45:37,680 --> 12:45:38,680
if you need more information
17526
12:45:40,020 --> 12:45:41,020
simply Google the route add command but
17527
12:45:43,020 --> 12:45:44,020
again I don't think you'll see it on the
17528
12:45:44,700 --> 12:45:45,700
network plus exam
17529
12:45:47,460 --> 12:45:48,460
finally I mentioned that there were some
17530
12:45:49,320 --> 12:45:50,320
important terms we had to mention when
17531
12:45:51,776 --> 12:45:52,776
we talk about routing the first is the
17532
12:45:54,416 --> 12:45:55,416
hop count this is the number of hops it
17533
12:45:58,080 --> 12:45:59,080
takes to reach a connection or before an
17534
12:46:00,540 --> 12:46:01,540
appropriate connection is made if you
17535
12:46:02,580 --> 12:46:03,580
remember when we used the trace route
17536
12:46:04,500 --> 12:46:05,500
command
17537
12:46:05,640 --> 12:46:06,640
remember that was trace route it went
17538
12:46:08,520 --> 12:46:09,520
through a number of hops or a number of
17539
12:46:10,320 --> 12:46:11,320
routers until it got from our computer
17540
12:46:12,660 --> 12:46:13,660
to for instance Googles so if our
17541
12:46:15,840 --> 12:46:16,840
computer and the destination computer
17542
12:46:17,820 --> 12:46:18,820
are represented by these two circles and
17543
12:46:21,180 --> 12:46:22,180
let's say we have our internal router so
17544
12:46:24,596 --> 12:46:25,596
for instance perhaps we are in a
17545
12:46:29,840 --> 12:46:30,840
10.0.0.xnetwork and then they're on
17546
12:46:32,276 --> 12:46:33,276
their own network as well
17547
12:46:35,220 --> 12:46:36,220
let's say that this is a for instance uh
17548
12:46:44,540 --> 12:46:45,540
124.68.24.3 Network
17549
12:46:46,860 --> 12:46:47,860
now we need to get from hours to theirs
17550
12:46:49,800 --> 12:46:50,800
and so let's say there are a number of
17551
12:46:52,740 --> 12:46:53,740
different routers in between well in
17552
12:46:54,540 --> 12:46:55,540
this case we have one two three four
17553
12:46:57,900 --> 12:46:58,900
five six hops between us and the
17554
12:47:01,500 --> 12:47:02,500
destination
17555
12:47:02,820 --> 12:47:03,820
so if there are an infinite number of
17556
12:47:05,276 --> 12:47:06,276
hops that means that the destination is
17557
12:47:07,980 --> 12:47:08,980
unreachable or that for some reason
17558
12:47:10,320 --> 12:47:11,320
we're getting caught into some sort of
17559
12:47:12,416 --> 12:47:13,416
loop
17560
12:47:13,800 --> 12:47:14,800
so the Hops keep coming back to itself
17561
12:47:17,220 --> 12:47:18,220
one another way that this can you can
17562
12:47:18,840 --> 12:47:19,840
see this as I erase this is for instance
17563
12:47:21,320 --> 12:47:22,320
we have
17564
12:47:25,200 --> 12:47:26,200
A system that looks something like
17565
12:47:27,596 --> 12:47:28,596
this and these are each routers
17566
12:47:31,140 --> 12:47:32,140
so what might happen
17567
12:47:32,936 --> 12:47:33,936
as I draw out all the connections
17568
12:47:35,936 --> 12:47:36,936
is the route might go from here one hop
17569
12:47:39,596 --> 12:47:40,596
to here and then instead of going to the
17570
12:47:42,180 --> 12:47:43,180
destination it simply goes like this
17571
12:47:44,880 --> 12:47:45,880
because
17572
12:47:46,500 --> 12:47:47,500
this could be a valid way of getting to
17573
12:47:49,860 --> 12:47:50,860
the router right we could hop here and
17574
12:47:52,616 --> 12:47:53,616
then we could go over there but instead
17575
12:47:55,500 --> 12:47:56,500
it hops and then this one sends it along
17576
12:47:58,436 --> 12:47:59,436
this route so we move here and basically
17577
12:48:02,160 --> 12:48:03,160
we create a loop in which the
17578
12:48:04,436 --> 12:48:05,436
destination is never reachable now this
17579
12:48:06,660 --> 12:48:07,660
could be because of some sort of poor uh
17580
12:48:09,660 --> 12:48:10,660
routing table and what you would need to
17581
12:48:11,580 --> 12:48:12,580
do is basically tell one of these
17582
12:48:13,020 --> 12:48:14,020
routers that the destination goes over
17583
12:48:15,480 --> 12:48:16,480
here
17584
12:48:16,616 --> 12:48:17,616
the next term is What's called the cost
17585
12:48:19,140 --> 12:48:20,140
this is the number of uh or these are
17586
12:48:22,320 --> 12:48:23,320
the numbers rather that are associated
17587
12:48:24,060 --> 12:48:25,060
with traveling from point A to point B
17588
12:48:26,960 --> 12:48:27,960
generally this means Hops and several
17589
12:48:29,880 --> 12:48:30,880
different links along the path the lower
17590
12:48:32,640 --> 12:48:33,640
number of of
17591
12:48:34,680 --> 12:48:35,680
hops the better we are so the cost would
17592
12:48:38,580 --> 12:48:39,580
be how many hops total we need to travel
17593
12:48:41,276 --> 12:48:42,276
from point A to point B generally
17594
12:48:43,436 --> 12:48:44,436
speaking we're going to look at the
17595
12:48:45,900 --> 12:48:46,900
lowest number of hops possible but there
17596
12:48:49,256 --> 12:48:50,256
are some instances in which we could
17597
12:48:52,080 --> 12:48:53,080
want to go more hops or have a higher
17598
12:48:55,980 --> 12:48:56,980
cost through hops in order to save on
17599
12:48:59,820 --> 12:49:00,820
something else for instance latency
17600
12:49:01,680 --> 12:49:02,680
latency is the time it takes from a
17601
12:49:03,900 --> 12:49:04,900
packet to go from one location to
17602
12:49:05,880 --> 12:49:06,880
another so to give you an example of
17603
12:49:07,916 --> 12:49:08,916
what I was just talking about sometimes
17604
12:49:09,900 --> 12:49:10,900
we go route specific
17605
12:49:12,360 --> 12:49:13,360
which means that it's going to choose
17606
12:49:14,700 --> 12:49:15,700
this route because this is only two hops
17607
12:49:19,436 --> 12:49:20,436
however
17608
12:49:21,596 --> 12:49:22,596
let's say
17609
12:49:27,960 --> 12:49:28,960
let's say that instead of traveling this
17610
12:49:29,820 --> 12:49:30,820
let's say this was a dial-up connection
17611
12:49:31,800 --> 12:49:32,800
right here
17612
12:49:33,416 --> 12:49:34,416
and this was a broadband connection
17613
12:49:37,560 --> 12:49:38,560
well obviously
17614
12:49:39,540 --> 12:49:40,540
even though we have to go one two three
17615
12:49:42,660 --> 12:49:43,660
four hops as opposed to three on this
17616
12:49:45,416 --> 12:49:46,416
one
17617
12:49:46,436 --> 12:49:47,436
we would want to take the four hops
17618
12:49:48,660 --> 12:49:49,660
because the latency is going to be less
17619
12:49:50,936 --> 12:49:51,936
and so the cost would be determined
17620
12:49:53,460 --> 12:49:54,460
based not only in hops but on latency as
17621
12:49:56,276 --> 12:49:57,276
well
17622
12:49:57,660 --> 12:49:58,660
now convergence is the process of
17623
12:50:01,200 --> 12:50:02,200
routers discovering the network
17624
12:50:03,240 --> 12:50:04,240
structure has changed in this way it
17625
12:50:05,880 --> 12:50:06,880
updates the routing tables to the
17626
12:50:07,560 --> 12:50:08,560
knowledge of the networks so for
17627
12:50:09,300 --> 12:50:10,300
instance
17628
12:50:11,700 --> 12:50:12,700
if we have two different paths that a
17629
12:50:14,460 --> 12:50:15,460
route could take
17630
12:50:16,380 --> 12:50:17,380
it could either go
17631
12:50:18,596 --> 12:50:19,596
like this or
17632
12:50:22,320 --> 12:50:23,320
like this we would want to know if one
17633
12:50:25,616 --> 12:50:26,616
of the connections had been severed and
17634
12:50:28,140 --> 12:50:29,140
then this routing table would be updated
17635
12:50:30,840 --> 12:50:31,840
to know don't go on this route instead
17636
12:50:34,320 --> 12:50:35,320
go on that route
17637
12:50:35,936 --> 12:50:36,936
the process of this happening
17638
12:50:38,400 --> 12:50:39,400
is called convergence
17639
12:50:41,640 --> 12:50:42,640
so although this module might have been
17640
12:50:44,460 --> 12:50:45,460
short and a brief overview of routing we
17641
12:50:46,980 --> 12:50:47,980
went over some key things first of all
17642
12:50:48,596 --> 12:50:49,596
we talked about a router this is the
17643
12:50:50,880 --> 12:50:51,880
device that generally allows us to
17644
12:50:52,616 --> 12:50:53,616
connect our Lan out to a Wan
17645
12:50:56,160 --> 12:50:57,160
it does this by operating on layer 3 of
17646
12:50:59,276 --> 12:51:00,276
The OSI model which again is responsible
17647
12:51:02,340 --> 12:51:03,340
for IP addresses as opposed to switches
17648
12:51:05,756 --> 12:51:06,756
which work with Mac addresses and
17649
12:51:07,740 --> 12:51:08,740
therefore operate on layer 2. we also
17650
12:51:09,900 --> 12:51:10,900
talked about how a router functions in
17651
12:51:12,596 --> 12:51:13,596
this case we talked about the fact that
17652
12:51:14,580 --> 12:51:15,580
a router has what's called a routing
17653
12:51:16,980 --> 12:51:17,980
table
17654
12:51:18,776 --> 12:51:19,776
which can sometimes be called an ARP
17655
12:51:21,116 --> 12:51:22,116
table
17656
12:51:22,680 --> 12:51:23,680
the ARP table
17657
12:51:24,380 --> 12:51:25,380
tells it where an IP address goes to get
17658
12:51:29,340 --> 12:51:30,340
to a specific place so it Maps basic IPS
17659
12:51:31,680 --> 12:51:32,680
to Mac addresses and then the routing
17660
12:51:33,776 --> 12:51:34,776
table would say how many routes you take
17661
12:51:36,116 --> 12:51:37,116
to get to a specific node on the network
17662
12:51:39,960 --> 12:51:40,960
we also looked at static routing which
17663
12:51:41,880 --> 12:51:42,880
is manually updating the routing table
17664
12:51:43,916 --> 12:51:44,916
so that way you can tell it where to go
17665
12:51:46,980 --> 12:51:47,980
we also talked about some key terms
17666
12:51:48,660 --> 12:51:49,660
including hop counts which would be like
17667
12:51:51,060 --> 12:51:52,060
the number of places we're going to go
17668
12:51:52,860 --> 12:51:53,860
if we're going to take a trip this would
17669
12:51:55,020 --> 12:51:56,020
be for instance the miles
17670
12:51:58,740 --> 12:51:59,740
we looked at the cost which basically
17671
12:52:00,960 --> 12:52:01,960
means we're going to take several things
17672
12:52:02,640 --> 12:52:03,640
into consideration when determining our
17673
12:52:05,936 --> 12:52:06,936
trip
17674
12:52:07,140 --> 12:52:08,140
for instance if one has a highway
17675
12:52:11,880 --> 12:52:12,880
whereas the other are a bunch of local
17676
12:52:13,980 --> 12:52:14,980
roads with stop lights
17677
12:52:17,640 --> 12:52:18,640
then even though it might be more miles
17678
12:52:20,096 --> 12:52:21,096
to go on the Highway we're going to go
17679
12:52:23,820 --> 12:52:24,820
there as opposed to this one with the
17680
12:52:25,256 --> 12:52:26,256
stop lights because we know we're
17681
12:52:26,220 --> 12:52:27,220
getting there faster
17682
12:52:27,840 --> 12:52:28,840
finally convergence is keeping all these
17683
12:52:30,180 --> 12:52:31,180
routing tables up to date
17684
12:52:32,820 --> 12:52:33,820
that way we know which route is the most
17685
12:52:35,220 --> 12:52:36,220
effective at any one time
17686
12:52:38,700 --> 12:52:39,700
in the next module I'm going to talk
17687
12:52:40,380 --> 12:52:41,380
more about how all this works in Dynamic
17688
12:52:43,800 --> 12:52:44,800
routing and the protocols that are
17689
12:52:45,900 --> 12:52:46,900
involved with it
17690
12:52:50,730 --> 12:52:51,730
[Music]
17691
12:52:59,416 --> 12:53:00,416
thank you
17692
12:53:07,080 --> 12:53:08,080
welcome to module 8 lesson 3A on routing
17693
12:53:10,436 --> 12:53:11,436
metrics or if you're in the UK routing
17694
12:53:13,256 --> 12:53:14,256
metrics
17695
12:53:15,720 --> 12:53:16,720
so this is a little bit esoteric in as
17696
12:53:18,060 --> 12:53:19,060
much as
17697
12:53:19,256 --> 12:53:20,256
you're better off configuring routing
17698
12:53:21,596 --> 12:53:22,596
and playing with this and doing Hands-On
17699
12:53:23,936 --> 12:53:24,936
labs which you don't do for the content
17700
12:53:27,060 --> 12:53:28,060
Network plus but if you're doing a CCNA
17701
12:53:29,640 --> 12:53:30,640
exam for Cisco for example you'd
17702
12:53:31,436 --> 12:53:32,436
actually have examples where you could
17703
12:53:33,540 --> 12:53:34,540
see this and been affected as you
17704
12:53:35,880 --> 12:53:36,880
configure the different routing
17705
12:53:37,860 --> 12:53:38,860
protocols and add more hops or other
17706
12:53:40,616 --> 12:53:41,616
devices
17707
12:53:42,180 --> 12:53:43,180
but we'll do our best we're going to
17708
12:53:44,220 --> 12:53:45,220
look at routing metrics the MTU
17709
12:53:47,820 --> 12:53:48,820
metric costs latency load reliability
17710
12:53:52,616 --> 12:53:53,616
so routing metrics and tables on a
17711
12:53:55,800 --> 12:53:56,800
router
17712
12:53:57,300 --> 12:53:58,300
and it's actually the same for servers
17713
12:53:59,040 --> 12:54:00,040
as well
17714
12:54:00,180 --> 12:54:01,180
and the writing table can contain a
17715
12:54:02,580 --> 12:54:03,580
field known as the metric
17716
12:54:04,860 --> 12:54:05,860
now a metric is a value and that value
17717
12:54:06,900 --> 12:54:07,900
can be made from a number of different
17718
12:54:09,180 --> 12:54:10,180
factors depending on the route the
17719
12:54:12,240 --> 12:54:13,240
routing protocol
17720
12:54:14,460 --> 12:54:15,460
this is used by the router when it runs
17721
12:54:18,180 --> 12:54:19,180
a mathematical algorithm to work out the
17722
12:54:21,060 --> 12:54:22,060
best path to get from a which will be
17723
12:54:23,880 --> 12:54:24,880
the local router 2B which is the remote
17724
12:54:27,480 --> 12:54:28,480
router
17725
12:54:30,416 --> 12:54:31,416
now I issue the show IP routes on a
17726
12:54:33,900 --> 12:54:34,900
router in the image here and I just
17727
12:54:36,720 --> 12:54:37,720
highlighted MD if you did look at the
17728
12:54:39,720 --> 12:54:40,720
table there is short for eigrp on Cisco
17729
12:54:44,220 --> 12:54:45,220
routing tables it'd be different if
17730
12:54:45,720 --> 12:54:46,720
you're using Juniper or a different
17731
12:54:47,400 --> 12:54:48,400
device but just for your information the
17732
12:54:50,580 --> 12:54:51,580
different numbers there are the routing
17733
12:54:52,560 --> 12:54:53,560
metrics the ergrp is calculated based
17734
12:54:56,160 --> 12:54:57,160
upon the location of the different
17735
12:54:58,080 --> 12:54:59,080
networks which are 34 uh
17736
12:55:03,020 --> 12:55:04,020
4.4.4.4 the 23 Network 24 and the 12
17737
12:55:07,140 --> 12:55:08,140
Network
17738
12:55:08,220 --> 12:55:09,220
don't worry too much about that but I
17739
12:55:09,960 --> 12:55:10,960
just wanted to show you that you can
17740
12:55:11,160 --> 12:55:12,160
actually see it in a routing table and
17741
12:55:13,740 --> 12:55:14,740
the number 90 before the
17742
12:55:16,680 --> 12:55:17,680
the routing metric there is the
17743
12:55:18,960 --> 12:55:19,960
administrative distance that um is is
17744
12:55:22,320 --> 12:55:23,320
allocated to the protocol and for ergrp
17745
12:55:25,560 --> 12:55:26,560
it's um 90 internally ergrp
17746
12:55:29,936 --> 12:55:30,936
so if a router has different routes to
17747
12:55:32,580 --> 12:55:33,580
the same network the routing metric
17748
12:55:34,320 --> 12:55:35,320
helps the router decide which of these
17749
12:55:36,660 --> 12:55:37,660
routes to choose because you could have
17750
12:55:38,880 --> 12:55:39,880
30 40 50 plus ways to get from A to B
17751
12:55:43,400 --> 12:55:44,400
and the writing table will just be too
17752
12:55:46,560 --> 12:55:47,560
big and the router would crash so it
17753
12:55:48,960 --> 12:55:49,960
uses the best path and inserts the best
17754
12:55:51,240 --> 12:55:52,240
path in the routing table
17755
12:55:54,180 --> 12:55:55,180
all right each writing protocol uses a
17756
12:55:56,520 --> 12:55:57,520
different metric I think you probably
17757
12:55:58,256 --> 12:55:59,256
need an overview just for the network
17758
12:55:59,880 --> 12:56:00,880
Plus
17759
12:56:00,960 --> 12:56:01,960
so we've got two routers a router one
17760
12:56:03,240 --> 12:56:04,240
and a router 11 between these two
17761
12:56:05,276 --> 12:56:06,276
routers you've got nine other routers
17762
12:56:07,500 --> 12:56:08,500
that connect to different Networks
17763
12:56:10,020 --> 12:56:11,020
and you can see the different routers
17764
12:56:11,820 --> 12:56:12,820
there path x y and z are the different
17765
12:56:14,820 --> 12:56:15,820
paths in order to get to router 11 and
17766
12:56:18,416 --> 12:56:19,416
of course you could make it more
17767
12:56:19,560 --> 12:56:20,560
complicated by connecting all of the
17768
12:56:21,960 --> 12:56:22,960
routers in between the paths which may
17769
12:56:23,756 --> 12:56:24,756
well be the case
17770
12:56:25,980 --> 12:56:26,980
so you want to get from router 1 to
17771
12:56:28,020 --> 12:56:29,020
router 11 and there's three different
17772
12:56:29,820 --> 12:56:30,820
paths to choose from
17773
12:56:32,460 --> 12:56:33,460
sake of convenience as I said x y and z
17774
12:56:35,040 --> 12:56:36,040
are the different path names writing
17775
12:56:37,200 --> 12:56:38,200
protocols will choose a route with the
17776
12:56:40,080 --> 12:56:41,080
lowest metric
17777
12:56:42,720 --> 12:56:43,720
now if we use rip routing information
17778
12:56:44,756 --> 12:56:45,756
protocol it only uses hop count it
17779
12:56:48,540 --> 12:56:49,540
doesn't care about the speed of the link
17780
12:56:50,276 --> 12:56:51,276
or if the Link's reliable or anything
17781
12:56:52,140 --> 12:56:53,140
like that it's
17782
12:56:54,240 --> 12:56:55,240
um a fairly old writing protocol and it
17783
12:56:57,180 --> 12:56:58,180
was built for quite small networks
17784
12:56:58,980 --> 12:56:59,980
because all networks were small at the
17785
12:57:00,720 --> 12:57:01,720
time
17786
12:57:02,160 --> 12:57:03,160
and so you can see there that there's uh
17787
12:57:05,880 --> 12:57:06,880
one path has got three hops one has got
17788
12:57:08,820 --> 12:57:09,820
one two three four hops in the middle if
17789
12:57:11,460 --> 12:57:12,460
you're not counting the um source and
17790
12:57:13,500 --> 12:57:14,500
destination the other has two routers
17791
12:57:16,320 --> 12:57:17,320
nine and ten so that's going to be the
17792
12:57:18,060 --> 12:57:19,060
shortest amount of hops
17793
12:57:21,596 --> 12:57:22,596
two hops four or three
17794
12:57:26,580 --> 12:57:27,580
so if rip chooses the route between
17795
12:57:28,616 --> 12:57:29,616
router 1 and 11 it will choose the best
17796
12:57:31,380 --> 12:57:32,380
path as path X
17797
12:57:34,256 --> 12:57:35,256
it's got the lowest top count
17798
12:57:36,900 --> 12:57:37,900
now I've introduced a problem here I've
17799
12:57:39,480 --> 12:57:40,480
actually shown you the speed of the
17800
12:57:41,460 --> 12:57:42,460
links and the speed of path X is only
17801
12:57:44,096 --> 12:57:45,096
56k
17802
12:57:45,720 --> 12:57:46,720
which is a crazy slow when you compare
17803
12:57:47,880 --> 12:57:48,880
it to path Y which is one Meg however
17804
12:57:51,060 --> 12:57:52,060
rip won't understand this now you can
17805
12:57:53,880 --> 12:57:54,880
configure it
17806
12:57:55,380 --> 12:57:56,380
and and do extra configurations to
17807
12:57:58,916 --> 12:57:59,916
um force it to take path y but by
17808
12:58:01,980 --> 12:58:02,980
default it um it won't it won't use path
17809
12:58:05,580 --> 12:58:06,580
y because the volt counts
17810
12:58:11,220 --> 12:58:12,220
so different routes and protocols use
17811
12:58:13,140 --> 12:58:14,140
different metrics and since the link
17812
12:58:15,720 --> 12:58:16,720
speed affects the throughput writing
17813
12:58:18,960 --> 12:58:19,960
protocols such as ergrp which is an
17814
12:58:21,300 --> 12:58:22,300
advanced writing protocol take into
17815
12:58:23,460 --> 12:58:24,460
account now it can take into account
17816
12:58:26,640 --> 12:58:27,640
Cisco's version of vrgrp only uses two
17817
12:58:30,180 --> 12:58:31,180
of the possible values
17818
12:58:32,756 --> 12:58:33,756
um that um are usable Within ergrp
17819
12:58:37,140 --> 12:58:38,140
and Cisco have their own version of
17820
12:58:39,060 --> 12:58:40,060
ergrp
17821
12:58:40,980 --> 12:58:41,980
now considering now ergb ergrp can
17822
12:58:44,880 --> 12:58:45,880
actually use five but we've only listed
17823
12:58:46,560 --> 12:58:47,560
the two used by Cisco devices here which
17824
12:58:48,660 --> 12:58:49,660
are bandwidth and delay
17825
12:58:52,200 --> 12:58:53,200
now considering the link speeds path Y
17826
12:58:54,240 --> 12:58:55,240
is better because we want to take the
17827
12:58:56,340 --> 12:58:57,340
faster
17828
12:58:57,416 --> 12:58:58,416
um route there
17829
12:58:59,096 --> 12:59:00,096
routine can be based on the following
17830
12:59:01,860 --> 12:59:02,860
factors the MTU
17831
12:59:04,080 --> 12:59:05,080
the costs cost latency administrative
17832
12:59:08,400 --> 12:59:09,400
distance shortest path bridging
17833
12:59:12,596 --> 12:59:13,596
uh the MTU
17834
12:59:14,820 --> 12:59:15,820
um is one factor as I've mentioned
17835
12:59:16,380 --> 12:59:17,380
stands for maximum transmission unit
17836
12:59:18,180 --> 12:59:19,180
this is the largest size of the packet
17837
12:59:20,580 --> 12:59:21,580
that can be transmitted across the link
17838
12:59:22,560 --> 12:59:23,560
without that packet being fragmented
17839
12:59:25,436 --> 12:59:26,436
fragmented means it gets chopped into
17840
12:59:27,480 --> 12:59:28,480
different sizes
17841
12:59:29,460 --> 12:59:30,460
and numbered sent and then reassembled
17842
12:59:32,520 --> 12:59:33,520
on the other side of the link and
17843
12:59:34,680 --> 12:59:35,680
obviously this can introduce the scope
17844
12:59:36,540 --> 12:59:37,540
for errors and obviously there's delay
17845
12:59:38,660 --> 12:59:39,660
while this fragmentation takes place
17846
12:59:42,660 --> 12:59:43,660
thank you also overhead involved because
17847
12:59:45,300 --> 12:59:46,300
of the acknowledgments each packet is
17848
12:59:47,400 --> 12:59:48,400
sent and received as it goes along and
17849
12:59:49,800 --> 12:59:50,800
it could be requested to be
17850
12:59:51,000 --> 12:59:52,000
re-transmitted also
17851
12:59:53,220 --> 12:59:54,220
largest packet you can send by an
17852
12:59:55,140 --> 12:59:56,140
Ethernet Network because of the way the
17853
12:59:56,756 --> 12:59:57,756
technology is designed is a 1500 byte
17854
13:00:01,560 --> 13:00:02,560
now cost I actually did an output here
17855
13:00:04,256 --> 13:00:05,256
of a router running ospf or an interface
17856
13:00:07,980 --> 13:00:08,980
running ospf here
17857
13:00:09,960 --> 13:00:10,960
and you can see the other information is
17858
13:00:12,360 --> 13:00:13,360
irrelevant for our purposes but the cost
17859
13:00:14,220 --> 13:00:15,220
has been allocated as 64. different
17860
13:00:17,580 --> 13:00:18,580
interface speeds are given different
17861
13:00:19,380 --> 13:00:20,380
costs by ospf
17862
13:00:25,320 --> 13:00:26,320
total cost so this link and the other
17863
13:00:27,900 --> 13:00:28,900
link and all the other links between and
17864
13:00:30,540 --> 13:00:31,540
the hosts are added up together and then
17865
13:00:32,820 --> 13:00:33,820
the best cast which is the lowest one is
17866
13:00:35,880 --> 13:00:36,880
installed into the routing table and the
17867
13:00:38,400 --> 13:00:39,400
other costs
17868
13:00:39,660 --> 13:00:40,660
um can be put into the topology table
17869
13:00:41,720 --> 13:00:42,720
for use if the best path goes down so
17870
13:00:44,880 --> 13:00:45,880
you can have second best third best and
17871
13:00:47,340 --> 13:00:48,340
so on
17872
13:00:49,916 --> 13:00:50,916
a router protocol can also use delay or
17873
13:00:52,380 --> 13:00:53,380
latency as a metric
17874
13:00:54,660 --> 13:00:55,660
delay refers to the delay of the links
17875
13:00:57,116 --> 13:00:58,116
across the route so is there any delays
17876
13:01:00,060 --> 13:01:01,060
to the packets been sent and received
17877
13:01:02,640 --> 13:01:03,640
a load I've actually issued a show
17878
13:01:04,916 --> 13:01:05,916
interfaces serial zero slash one on this
17879
13:01:07,740 --> 13:01:08,740
router and you can see some of the
17880
13:01:09,776 --> 13:01:10,776
metrics that are allocated
17881
13:01:12,900 --> 13:01:13,900
to this particular interface the mtus
17882
13:01:15,960 --> 13:01:16,960
1500 the bandwidth is 1544 so one Meg
17883
13:01:21,140 --> 13:01:22,140
delay and twenty thousand millisecs
17884
13:01:25,740 --> 13:01:26,740
a reliability 255 out of 255 is the best
17885
13:01:30,416 --> 13:01:31,416
it means um it's very reliable and that
17886
13:01:33,116 --> 13:01:34,116
if there's problems then the number goes
17887
13:01:35,936 --> 13:01:36,936
down like 10 out of two five five is
17888
13:01:38,040 --> 13:01:39,040
very bad
17889
13:01:39,060 --> 13:01:40,060
the transmission load is low it's the
17890
13:01:41,400 --> 13:01:42,400
lowest one out of two five five receive
17891
13:01:43,680 --> 13:01:44,680
load is one out of two five five
17892
13:01:46,200 --> 13:01:47,200
which is an arbitrary value
17893
13:01:49,080 --> 13:01:50,080
so load is the measure of traffic
17894
13:01:50,520 --> 13:01:51,520
consuming the links we don't want our
17895
13:01:52,256 --> 13:01:53,256
package to be traveling along a path
17896
13:01:53,756 --> 13:01:54,756
with high traffic
17897
13:01:56,040 --> 13:01:57,040
so the past with the lowest load would
17898
13:01:58,140 --> 13:01:59,140
be the best path if we're using load as
17899
13:02:00,416 --> 13:02:01,416
a metric of course
17900
13:02:02,400 --> 13:02:03,400
reliability is in there also which I've
17901
13:02:04,740 --> 13:02:05,740
discussed we want to take into
17902
13:02:06,660 --> 13:02:07,660
consideration the reliability of the
17903
13:02:08,400 --> 13:02:09,400
path
17904
13:02:09,480 --> 13:02:10,480
reliability metric has a value that
17905
13:02:12,596 --> 13:02:13,596
denotes a number of times any of the
17906
13:02:14,700 --> 13:02:15,700
following occurs the link goes down or
17907
13:02:17,700 --> 13:02:18,700
had errors at a certain period of time
17908
13:02:22,020 --> 13:02:23,020
the router protocol may use the
17909
13:02:24,116 --> 13:02:25,116
following one metric as in rip multiple
17910
13:02:27,180 --> 13:02:28,180
link characteristics to calculate a
17911
13:02:30,116 --> 13:02:31,116
metric for example ergrp which is
17912
13:02:33,360 --> 13:02:34,360
bandwidth and delay of the line
17913
13:02:37,040 --> 13:02:38,040
ergp uses characteristics to calculate a
17914
13:02:40,140 --> 13:02:41,140
metric for best path I've actually
17915
13:02:43,400 --> 13:02:44,400
done a output of a Cisco router here
17916
13:02:47,340 --> 13:02:48,340
for ergrp and you can see the different
17917
13:02:49,680 --> 13:02:50,680
metrics here some won't be used
17918
13:02:53,160 --> 13:02:54,160
you can actually affect this if you want
17919
13:02:55,980 --> 13:02:56,980
in the configuration normally best to
17920
13:02:58,320 --> 13:02:59,320
speak to a Cisco engineer before you do
17921
13:03:01,140 --> 13:03:02,140
this
17922
13:03:03,000 --> 13:03:04,000
so some of the delay characteristics are
17923
13:03:05,460 --> 13:03:06,460
delay bandwidth reliability load
17924
13:03:10,160 --> 13:03:11,160
and you can see others in there but
17925
13:03:12,900 --> 13:03:13,900
again it's bandwidth And Delay the line
17926
13:03:14,520 --> 13:03:15,520
is usually used
17927
13:03:17,580 --> 13:03:18,580
uh summary so far we've covered routing
17928
13:03:20,220 --> 13:03:21,220
metrics the MTU
17929
13:03:22,380 --> 13:03:23,380
metric costs uh latency load reliability
17930
13:03:27,060 --> 13:03:28,060
so that's all we need to know for now
17931
13:03:29,160 --> 13:03:30,160
thanks for watching
17932
13:03:35,300 --> 13:03:36,300
[Music]
17933
13:03:51,060 --> 13:03:52,060
welcome to module 8 lesson 3B routing
17934
13:03:54,300 --> 13:03:55,300
tables
17935
13:03:55,380 --> 13:03:56,380
another hard one to put in perspective
17936
13:03:57,240 --> 13:03:58,240
if we don't configure
17937
13:03:58,916 --> 13:03:59,916
live routers but we'll do our best we're
17938
13:04:01,860 --> 13:04:02,860
going to look at routing the routing
17939
13:04:03,300 --> 13:04:04,300
table
17940
13:04:04,560 --> 13:04:05,560
static routes and a static route example
17941
13:04:07,220 --> 13:04:08,220
and dynamic routing protocols only an
17942
13:04:11,160 --> 13:04:12,160
overview really and then an example and
17943
13:04:13,860 --> 13:04:14,860
physically connected Networks
17944
13:04:16,500 --> 13:04:17,500
so routing is the process of sending a
17945
13:04:19,800 --> 13:04:20,800
packet from a source Network to a
17946
13:04:22,800 --> 13:04:23,800
destination in another Network
17947
13:04:25,680 --> 13:04:26,680
we actually have to differentiate
17948
13:04:27,180 --> 13:04:28,180
between routing and packet switching
17949
13:04:29,520 --> 13:04:30,520
writing is a process where the router
17950
13:04:31,860 --> 13:04:32,860
actually decides the best route to get
17951
13:04:34,436 --> 13:04:35,436
from A to Z and then switching in the in
17952
13:04:38,400 --> 13:04:39,400
the context of sending IP packets is
17953
13:04:41,220 --> 13:04:42,220
actually pushing the packet out of the
17954
13:04:43,380 --> 13:04:44,380
correct interface I just want to do
17955
13:04:45,480 --> 13:04:46,480
highlight the difference between the two
17956
13:04:48,320 --> 13:04:49,320
and obviously we're looking at Network
17957
13:04:50,700 --> 13:04:51,700
plus level stuff here so there's two
17958
13:04:53,040 --> 13:04:54,040
aspects determining the optimal route
17959
13:04:55,256 --> 13:04:56,256
which is the routing part and then
17960
13:04:57,416 --> 13:04:58,416
pushing the packet through the network
17961
13:04:58,916 --> 13:04:59,916
which is the switching part
17962
13:05:02,400 --> 13:05:03,400
so routes are based on networks we don't
17963
13:05:04,740 --> 13:05:05,740
really
17964
13:05:06,480 --> 13:05:07,480
um
17965
13:05:07,200 --> 13:05:08,200
we don't want to concern ourselves with
17966
13:05:09,000 --> 13:05:10,000
host on networks because if you can
17967
13:05:10,740 --> 13:05:11,740
imagine even an Enterprise Network for
17968
13:05:13,380 --> 13:05:14,380
some large company could have thousands
17969
13:05:15,000 --> 13:05:16,000
of hosts
17970
13:05:16,380 --> 13:05:17,380
it'd be pointless every router having
17971
13:05:18,596 --> 13:05:19,596
thousands of hosts listed so what it
17972
13:05:21,060 --> 13:05:22,060
wants to do is focus on Networks
17973
13:05:23,460 --> 13:05:24,460
and then it will then switch the packet
17974
13:05:25,740 --> 13:05:26,740
to the correct Network and another
17975
13:05:28,320 --> 13:05:29,320
router and then finally the host address
17976
13:05:31,256 --> 13:05:32,256
in
17977
13:05:32,460 --> 13:05:33,460
the Mac part of the address will be
17978
13:05:34,380 --> 13:05:35,380
taken care of by the Lan switches
17979
13:05:38,640 --> 13:05:39,640
so a route is not based on the host
17980
13:05:40,980 --> 13:05:41,980
because the packets are routed through
17981
13:05:43,080 --> 13:05:44,080
the networks it doesn't use the physical
17982
13:05:45,116 --> 13:05:46,116
Mac address of the hosts
17983
13:05:48,360 --> 13:05:49,360
so here's the example we've got a a few
17984
13:05:51,776 --> 13:05:52,776
different I've shrunk down each switch
17985
13:05:53,820 --> 13:05:54,820
would have it could have a 12 or 24 host
17986
13:05:56,936 --> 13:05:57,936
connected but I've just added one and
17987
13:05:59,160 --> 13:06:00,160
you can see we've got three different
17988
13:06:00,416 --> 13:06:01,416
networks listed here the 192 a 10 and a
17989
13:06:03,060 --> 13:06:04,060
172 Network
17990
13:06:05,220 --> 13:06:06,220
so the MAC address of the destination
17991
13:06:08,096 --> 13:06:09,096
host is only used for the final delivery
17992
13:06:10,800 --> 13:06:11,800
so the switch if these are layer 2
17993
13:06:13,436 --> 13:06:14,436
switches which are my examples they are
17994
13:06:15,480 --> 13:06:16,480
it won't understand the IP
17995
13:06:18,776 --> 13:06:19,776
address portion of the packet because
17996
13:06:22,320 --> 13:06:23,320
we're looking inside the frame and it
17997
13:06:25,140 --> 13:06:26,140
will match the MAC address
17998
13:06:28,320 --> 13:06:29,320
to the correct port and then deliver the
17999
13:06:31,080 --> 13:06:32,080
frame to that particular Port this is
18000
13:06:33,540 --> 13:06:34,540
what our switches are concerned with
18001
13:06:34,980 --> 13:06:35,980
whereas all the routing between the
18002
13:06:36,776 --> 13:06:37,776
three routers in the diagram here
18003
13:06:38,400 --> 13:06:39,400
they're concerned with which network or
18004
13:06:40,500 --> 13:06:41,500
which Port which network is connected to
18005
13:06:43,200 --> 13:06:44,200
of the router
18006
13:06:44,756 --> 13:06:45,756
so the switch down here on the right if
18007
13:06:48,000 --> 13:06:49,000
you issue a show Mac address table on a
18008
13:06:50,580 --> 13:06:51,580
Cisco switch at least you'll see a map
18009
13:06:52,740 --> 13:06:53,740
in and you'll see which Mac address and
18010
13:06:55,200 --> 13:06:56,200
each one's unique is connected to which
18011
13:06:57,900 --> 13:06:58,900
physical ports and this particular one
18012
13:07:00,240 --> 13:07:01,240
they're all in the same VLAN because
18013
13:07:01,560 --> 13:07:02,560
we're not worried about
18014
13:07:03,596 --> 13:07:04,596
um into VLAN any any VLAN stuff here so
18015
13:07:07,256 --> 13:07:08,256
gigabit zero slash two zero slash two
18016
13:07:09,840 --> 13:07:10,840
zero slash two and fast ethernet zero
18017
13:07:12,060 --> 13:07:13,060
slash one if you see more than one host
18018
13:07:14,700 --> 13:07:15,700
connected to one port it means it's a
18019
13:07:17,520 --> 13:07:18,520
trunk and it's connected to another
18020
13:07:19,020 --> 13:07:20,020
switch somebody somewhere
18021
13:07:21,360 --> 13:07:22,360
so this switch down here would be
18022
13:07:23,096 --> 13:07:24,096
connected to another switch via a
18023
13:07:24,660 --> 13:07:25,660
gigabit Ethernet port and it's learned a
18024
13:07:27,116 --> 13:07:28,116
few host addresses that are connected to
18025
13:07:29,340 --> 13:07:30,340
that
18026
13:07:30,900 --> 13:07:31,900
all right so when we send packets out to
18027
13:07:32,936 --> 13:07:33,936
the internet the following is true the
18028
13:07:35,096 --> 13:07:36,096
routers have a database of routes stored
18029
13:07:37,680 --> 13:07:38,680
in a table called a routing table it
18030
13:07:39,776 --> 13:07:40,776
could actually be a database consisting
18031
13:07:41,700 --> 13:07:42,700
of one route or just connected routes
18032
13:07:44,096 --> 13:07:45,096
depends how we configure stuff really
18033
13:07:46,860 --> 13:07:47,860
the writers use this information in the
18034
13:07:48,660 --> 13:07:49,660
writing tables and they make a decision
18035
13:07:50,276 --> 13:07:51,276
based upon the next hop this is what
18036
13:07:52,916 --> 13:07:53,916
routers all do they send a packet to the
18037
13:07:55,800 --> 13:07:56,800
next hop
18038
13:07:56,880 --> 13:07:57,880
unless they are the the last hop in the
18039
13:07:59,936 --> 13:08:00,936
journey
18040
13:08:01,800 --> 13:08:02,800
so there's a routing table here you can
18041
13:08:04,680 --> 13:08:05,680
see uh there's a network been learned
18042
13:08:07,320 --> 13:08:08,320
and
18043
13:08:08,936 --> 13:08:09,936
if I just put the text here the routing
18044
13:08:11,276 --> 13:08:12,276
table contains the following the network
18045
13:08:12,596 --> 13:08:13,596
ID here the network is three zero zero
18046
13:08:16,800 --> 13:08:17,800
zero and it's actually found a host on
18047
13:08:18,840 --> 13:08:19,840
this network
18048
13:08:21,416 --> 13:08:22,416
destination Network address and subnet
18049
13:08:23,700 --> 13:08:24,700
mask I'm not sure how this is been
18050
13:08:25,436 --> 13:08:26,436
configured because I pulled this one off
18051
13:08:27,060 --> 13:08:28,060
the um off the internet you can actually
18052
13:08:29,640 --> 13:08:30,640
see at the bottom 10 10 23 0 is a
18053
13:08:33,300 --> 13:08:34,300
network found by ospf
18054
13:08:36,596 --> 13:08:37,596
and it will have the next top and
18055
13:08:38,936 --> 13:08:39,936
Gateway so if we go to the bottom 10 10
18056
13:08:43,320 --> 13:08:44,320
23 0 110 is the administrative distance
18057
13:08:47,276 --> 13:08:48,276
for rspf 20 is the cost
18058
13:08:50,340 --> 13:08:51,340
and it's been learned via the address 10
18059
13:08:54,240 --> 13:08:55,240
10 12.2 which will be another router
18060
13:08:57,180 --> 13:08:58,180
interface somewhere connected
18061
13:08:59,700 --> 13:09:00,700
it was actually learned one minute and
18062
13:09:01,616 --> 13:09:02,616
17 seconds ago via the fast ethernet 0 0
18063
13:09:05,460 --> 13:09:06,460
interface
18064
13:09:07,916 --> 13:09:08,916
all right so these the router has enough
18065
13:09:10,256 --> 13:09:11,256
information that if it wants to send any
18066
13:09:12,660 --> 13:09:13,660
packets to any host on the 10 10 23
18067
13:09:15,480 --> 13:09:16,480
Network it knows where to send it and it
18068
13:09:18,060 --> 13:09:19,060
also knows how fresh that route is
18069
13:09:23,880 --> 13:09:24,880
all right the metric metrics used to
18070
13:09:26,640 --> 13:09:27,640
decide which route is to be taken if if
18071
13:09:28,800 --> 13:09:29,800
multiple routes exist for a given
18072
13:09:30,776 --> 13:09:31,776
destination Network so we can see some
18073
13:09:34,276 --> 13:09:35,276
metrics here in fact
18074
13:09:37,020 --> 13:09:38,020
um squared in the yellow highlighting
18075
13:09:40,740 --> 13:09:41,740
you can see two routes have been learned
18076
13:09:43,020 --> 13:09:44,020
to the same network the reason is the
18077
13:09:46,140 --> 13:09:47,140
metric is exactly the same so it must be
18078
13:09:49,020 --> 13:09:50,020
exactly the same cost
18079
13:09:52,380 --> 13:09:53,380
to reach the destination via two
18080
13:09:55,200 --> 13:09:56,200
different IP addresses one seven two
18081
13:09:57,116 --> 13:09:58,116
twenty four one two two and one seven
18082
13:10:00,060 --> 13:10:01,060
two twenty four one three four so as
18083
13:10:01,980 --> 13:10:02,980
long as the costs are the same then
18084
13:10:05,116 --> 13:10:06,116
ergrp is configured to load balance over
18085
13:10:08,520 --> 13:10:09,520
those
18086
13:10:09,596 --> 13:10:10,596
I think with um Cisco ergrp
18087
13:10:13,080 --> 13:10:14,080
automatically load balances over up to
18088
13:10:15,596 --> 13:10:16,596
four links and you can change that value
18089
13:10:17,756 --> 13:10:18,756
up to 16. but this could change
18090
13:10:20,400 --> 13:10:21,400
depending on your platform
18091
13:10:23,400 --> 13:10:24,400
all right so the administrative distance
18092
13:10:25,256 --> 13:10:26,256
when a router's right running two roads
18093
13:10:27,180 --> 13:10:28,180
right on protocols such as rip and SPF
18094
13:10:29,276 --> 13:10:30,276
and everything else is equal
18095
13:10:32,040 --> 13:10:33,040
so for example rip and SPF it will use
18096
13:10:34,256 --> 13:10:35,256
the ad administrative distance to
18097
13:10:36,360 --> 13:10:37,360
determine which route to choose I've
18098
13:10:39,416 --> 13:10:40,416
configured uh two routers up here just
18099
13:10:42,360 --> 13:10:43,360
connected by a gigabit zero and zero
18100
13:10:44,756 --> 13:10:45,756
slash one
18101
13:10:45,776 --> 13:10:46,776
the top Network for the top link is 192.
18102
13:10:49,860 --> 13:10:50,860
the bot and it's using rip the bottom is
18103
13:10:51,900 --> 13:10:52,900
rspf and it's 172. and at the end we
18104
13:10:55,500 --> 13:10:56,500
have another Network a Ted Network that
18105
13:10:58,320 --> 13:10:59,320
is advertised via rip and ospf
18106
13:11:01,560 --> 13:11:02,560
so rip I know the administrative
18107
13:11:04,140 --> 13:11:05,140
distance is 120 ospf is 110 so routes to
18108
13:11:09,060 --> 13:11:10,060
get from router 0 to the 10 Network
18109
13:11:12,020 --> 13:11:13,020
should use ospf
18110
13:11:14,756 --> 13:11:15,756
and if the ospf network goes down or the
18111
13:11:17,756 --> 13:11:18,756
interface is really no SPF then the rip
18112
13:11:20,220 --> 13:11:21,220
Network could be chosen this is a part
18113
13:11:23,580 --> 13:11:24,580
of the output from a show ospf you can
18114
13:11:26,520 --> 13:11:27,520
see 120 is the ad one is how many hops
18115
13:11:31,860 --> 13:11:32,860
and under the 810 is the ad Slash 2 is
18116
13:11:35,400 --> 13:11:36,400
the cost because rspf uses a cost not a
18117
13:11:38,756 --> 13:11:39,756
hop value so it's the um the calculation
18118
13:11:42,660 --> 13:11:43,660
is used looking at the um speed of the
18119
13:11:45,720 --> 13:11:46,720
link is put into a formula
18120
13:11:48,360 --> 13:11:49,360
and each link between source and
18121
13:11:50,096 --> 13:11:51,096
destination is added to the cast so the
18122
13:11:52,500 --> 13:11:53,500
cost is only two which is the gigabit
18123
13:11:54,840 --> 13:11:55,840
Ethernet speed there
18124
13:11:56,756 --> 13:11:57,756
and it'll be the speed of the interface
18125
13:11:58,740 --> 13:11:59,740
that the 10 networks connected to
18126
13:12:01,436 --> 13:12:02,436
so if if I try and Trace traffic going
18127
13:12:05,096 --> 13:12:06,096
from router 0 to the 10 Network you can
18128
13:12:08,460 --> 13:12:09,460
see it's traced and it's used the next
18129
13:12:10,800 --> 13:12:11,800
hop address of
18130
13:12:14,180 --> 13:12:15,180
172.16.1.2 which is the gigabit uh zero
18131
13:12:18,416 --> 13:12:19,416
slash one of router one
18132
13:12:21,000 --> 13:12:22,000
and so that's basically the preferred
18133
13:12:23,220 --> 13:12:24,220
path if for some reason that path went
18134
13:12:25,436 --> 13:12:26,436
down it would start using the next best
18135
13:12:27,900 --> 13:12:28,900
a next best ad which is Rip
18136
13:12:31,860 --> 13:12:32,860
writing table writing information is
18137
13:12:34,380 --> 13:12:35,380
populated through a few different means
18138
13:12:36,480 --> 13:12:37,480
it can be a connected route actually a
18139
13:12:39,540 --> 13:12:40,540
static route I I suppose I said
18140
13:12:42,360 --> 13:12:43,360
connected there or a dynamic routing
18141
13:12:44,460 --> 13:12:45,460
protocol what you can figure depends on
18142
13:12:46,860 --> 13:12:47,860
your network if it's a tiny little
18143
13:12:48,480 --> 13:12:49,480
Network or if it's in a remote office
18144
13:12:51,300 --> 13:12:52,300
somewhere then you probably use a static
18145
13:12:53,640 --> 13:12:54,640
route to just send all traffic to the
18146
13:12:55,980 --> 13:12:56,980
next top router
18147
13:12:58,200 --> 13:12:59,200
so this is the show IP route and I've
18148
13:13:00,776 --> 13:13:01,776
highlighted in red the connected routes
18149
13:13:03,080 --> 13:13:04,080
for router 0.
18150
13:13:06,720 --> 13:13:07,720
it's a 17216 another 192.1681 network is
18151
13:13:10,980 --> 13:13:11,980
showing as C connected are in Cisco at
18152
13:13:15,540 --> 13:13:16,540
least that's for it oh stands for ospf
18153
13:13:17,820 --> 13:13:18,820
and L stands for local
18154
13:13:22,980 --> 13:13:23,980
static route is a route that is manually
18155
13:13:25,916 --> 13:13:26,916
added to a router by administrator
18156
13:13:28,616 --> 13:13:29,616
so you can see here router 1 on the left
18157
13:13:30,960 --> 13:13:31,960
has got a default static route
18158
13:13:33,800 --> 13:13:34,800
which you can recognize it because it's
18159
13:13:36,060 --> 13:13:37,060
all zeros
18160
13:13:38,340 --> 13:13:39,340
I'll give you an example in a moment if
18161
13:13:40,616 --> 13:13:41,616
router 1 receives traffic destined to
18162
13:13:43,140 --> 13:13:44,140
any network other than a local one are
18163
13:13:45,596 --> 13:13:46,596
you one that's connected it should
18164
13:13:47,340 --> 13:13:48,340
really know where to send that traffic
18165
13:13:48,720 --> 13:13:49,720
if there's no entry listed then it by
18166
13:13:51,540 --> 13:13:52,540
default routers will drop the packets
18167
13:13:55,200 --> 13:13:56,200
since R2 is the next hop for router want
18168
13:13:57,540 --> 13:13:58,540
to reach the internet what we can
18169
13:13:59,220 --> 13:14:00,220
basically do is put a static route on
18170
13:14:00,840 --> 13:14:01,840
router 1 saying send any traffic to any
18171
13:14:03,480 --> 13:14:04,480
network over to R2 and let R2 worry
18172
13:14:06,596 --> 13:14:07,596
about where to send it
18173
13:14:09,540 --> 13:14:10,540
when our one receives the traffic for a
18174
13:14:11,340 --> 13:14:12,340
network it's not available it will now
18175
13:14:12,840 --> 13:14:13,840
send it out of its interface using the
18176
13:14:15,300 --> 13:14:16,300
default static routes I've actually
18177
13:14:17,520 --> 13:14:18,520
configured a static route here on a
18178
13:14:20,276 --> 13:14:21,276
Cisco router
18179
13:14:22,580 --> 13:14:23,580
iprout000 and then zero zero zero zero
18180
13:14:25,860 --> 13:14:26,860
so any
18181
13:14:27,000 --> 13:14:28,000
and IP address
18182
13:14:28,880 --> 13:14:29,880
and any network go out to our gigabit
18183
13:14:33,060 --> 13:14:34,060
Ethernet interface instead of g00 I
18184
13:14:36,660 --> 13:14:37,660
could have put an IP address for the
18185
13:14:38,040 --> 13:14:39,040
next top router as long as the router
18186
13:14:40,140 --> 13:14:41,140
knows how to get there
18187
13:14:42,000 --> 13:14:43,000
and for the R2 you can do the same thing
18188
13:14:44,820 --> 13:14:45,820
you could have a static route as long as
18189
13:14:46,860 --> 13:14:47,860
you know your next hop which would be
18190
13:14:48,540 --> 13:14:49,540
your ISP router let your ISP take care
18191
13:14:51,840 --> 13:14:52,840
of any routing decisions
18192
13:14:57,596 --> 13:14:58,596
all right Dynamic routing practicals
18193
13:14:59,640 --> 13:15:00,640
this is a routing protocol that
18194
13:15:01,680 --> 13:15:02,680
dynamically builds routing information
18195
13:15:03,180 --> 13:15:04,180
such as the following the network the
18196
13:15:05,756 --> 13:15:06,756
next harp and it will build a topology
18197
13:15:08,340 --> 13:15:09,340
table and from the topology table it
18198
13:15:10,980 --> 13:15:11,980
will choose the best route to put in the
18199
13:15:12,900 --> 13:15:13,900
routing table and the topology table
18200
13:15:16,500 --> 13:15:17,500
can supply second third and fourth best
18201
13:15:19,740 --> 13:15:20,740
routes and so on
18202
13:15:21,416 --> 13:15:22,416
static routing does not do well in large
18203
13:15:23,936 --> 13:15:24,936
networks because you would have to
18204
13:15:25,320 --> 13:15:26,320
manually add 5 10 15 20 routes per
18205
13:15:30,360 --> 13:15:31,360
router
18206
13:15:32,040 --> 13:15:33,040
so you can imagine you're going to have
18207
13:15:33,300 --> 13:15:34,300
a lot of work there if you decide to
18208
13:15:35,400 --> 13:15:36,400
change the IP address and or even add
18209
13:15:37,500 --> 13:15:38,500
one device
18210
13:15:39,240 --> 13:15:40,240
so you don't want your routers to
18211
13:15:41,220 --> 13:15:42,220
automatically learn the routes update
18212
13:15:43,560 --> 13:15:44,560
any changes without you having to worry
18213
13:15:45,300 --> 13:15:46,300
about it and this is where routing
18214
13:15:47,340 --> 13:15:48,340
protocols make our life a lot easier
18215
13:15:50,040 --> 13:15:51,040
once you've configured which networks
18216
13:15:51,900 --> 13:15:52,900
you want to advertise then depending on
18217
13:15:54,060 --> 13:15:55,060
which protocol you're using
18218
13:15:55,980 --> 13:15:56,980
and the writing protocol will go ahead
18219
13:15:57,776 --> 13:15:58,776
and run on automatic settings unless you
18220
13:16:00,000 --> 13:16:01,000
change the settings for whatever reason
18221
13:16:03,416 --> 13:16:04,416
the routers use the router protocols to
18222
13:16:05,936 --> 13:16:06,936
learn about available routes to build a
18223
13:16:07,800 --> 13:16:08,800
routing table
18224
13:16:10,560 --> 13:16:11,560
and the routing protocol communicates
18225
13:16:13,740 --> 13:16:14,740
with the same router protocol on another
18226
13:16:15,540 --> 13:16:16,540
router you can't have rip on one router
18227
13:16:18,300 --> 13:16:19,300
communicating with rspf on the other
18228
13:16:20,220 --> 13:16:21,220
because they work in entirely different
18229
13:16:22,320 --> 13:16:23,320
ways and use different protocols and
18230
13:16:25,680 --> 13:16:26,680
ports
18231
13:16:27,116 --> 13:16:28,116
to um send their information
18232
13:16:30,540 --> 13:16:31,540
so this information is placed in the
18233
13:16:32,340 --> 13:16:33,340
writing table
18234
13:16:34,200 --> 13:16:35,200
so as an example here router one two and
18235
13:16:36,416 --> 13:16:37,416
three you've got some different networks
18236
13:16:38,640 --> 13:16:39,640
connected
18237
13:16:40,800 --> 13:16:41,800
a pc1's default gateway because PCS
18238
13:16:43,560 --> 13:16:44,560
won't do the routing will always be
18239
13:16:44,936 --> 13:16:45,936
router one you'll just send all traffic
18240
13:16:47,040 --> 13:16:48,040
to whatever the IP address is of the
18241
13:16:50,520 --> 13:16:51,520
router there normally in In fairness the
18242
13:16:52,980 --> 13:16:53,980
PC is connected to a switch and then a
18243
13:16:54,840 --> 13:16:55,840
router this is just a simplified diagram
18244
13:16:58,680 --> 13:16:59,680
so if router one has two routes to the
18245
13:17:00,960 --> 13:17:01,960
internet then it will choose the best
18246
13:17:02,096 --> 13:17:03,096
one depending on the routing protocol
18247
13:17:03,776 --> 13:17:04,776
unless you've changed the settings you
18248
13:17:06,720 --> 13:17:07,720
can obviously manipulate things
18249
13:17:09,660 --> 13:17:10,660
if rip has been used then it will choose
18250
13:17:11,580 --> 13:17:12,580
a hop count and it will choose the
18251
13:17:13,140 --> 13:17:14,140
lowest top count so it will be router 1
18252
13:17:15,060 --> 13:17:16,060
to router 3. even though it's
18253
13:17:18,380 --> 13:17:19,380
128k the link there
18254
13:17:22,080 --> 13:17:23,080
if rspf is being used
18255
13:17:25,256 --> 13:17:26,256
um then it will choose R2
18256
13:17:27,720 --> 13:17:28,720
that might not be correct actually if I
18257
13:17:29,756 --> 13:17:30,756
look at the diagram
18258
13:17:31,616 --> 13:17:32,616
you'd have to add up the um speed of the
18259
13:17:34,436 --> 13:17:35,436
links but the speed between router 2 and
18260
13:17:36,540 --> 13:17:37,540
router 3 is being put as 128k so um that
18261
13:17:40,320 --> 13:17:41,320
isn't quite correct say you've got a one
18262
13:17:41,820 --> 13:17:42,820
Meg link between router one and two and
18263
13:17:44,400 --> 13:17:45,400
then two and three then ospf should
18264
13:17:47,096 --> 13:17:48,096
choose the
18265
13:17:49,256 --> 13:17:50,256
um that link even though it's more hops
18266
13:17:51,900 --> 13:17:52,900
because it's only looking at the costs
18267
13:17:55,800 --> 13:17:56,800
so Dynamic router protocol also allows a
18268
13:17:58,256 --> 13:17:59,256
router to reroute around a fellow link
18269
13:18:00,240 --> 13:18:01,240
and this is where the topology table
18270
13:18:01,616 --> 13:18:02,616
will come in it will have a um ability
18271
13:18:04,740 --> 13:18:05,740
or most advanced protocols do to have
18272
13:18:07,500 --> 13:18:08,500
some backup routes in the topology table
18273
13:18:09,300 --> 13:18:10,300
that will quickly take over
18274
13:18:12,720 --> 13:18:13,720
uh physically connected networks routers
18275
13:18:15,416 --> 13:18:16,416
interfaces physically connected to a
18276
13:18:17,700 --> 13:18:18,700
network it obviously knows how to reach
18277
13:18:19,616 --> 13:18:20,616
that Network
18278
13:18:21,180 --> 13:18:22,180
since r1's interface is directly
18279
13:18:23,340 --> 13:18:24,340
connected to these networks it already
18280
13:18:24,840 --> 13:18:25,840
knows how to reach them
18281
13:18:28,200 --> 13:18:29,200
all right so we've covered routing just
18282
13:18:30,540 --> 13:18:31,540
in an overview the routing table
18283
13:18:33,240 --> 13:18:34,240
static routes an example of a static
18284
13:18:35,936 --> 13:18:36,936
route autonomic routing protocols as an
18285
13:18:38,880 --> 13:18:39,880
example and then physically connected
18286
13:18:41,640 --> 13:18:42,640
Networks
18287
13:18:43,256 --> 13:18:44,256
now your physically connected networks
18288
13:18:45,180 --> 13:18:46,180
you don't have to advertise but
18289
13:18:47,880 --> 13:18:48,880
obviously if you want traffic to be able
18290
13:18:49,320 --> 13:18:50,320
to reach that Network then you're going
18291
13:18:50,640 --> 13:18:51,640
to need to add a dynamic or static route
18292
13:18:53,700 --> 13:18:54,700
but that's all for now thanks for
18293
13:18:55,020 --> 13:18:56,020
watching
18294
13:19:01,600 --> 13:19:02,600
[Music]
18295
13:19:21,740 --> 13:19:22,740
local area networks Dynamic routing and
18296
13:19:25,740 --> 13:19:26,740
protocols
18297
13:19:27,000 --> 13:19:28,000
so in the previous module we discussed
18298
13:19:29,160 --> 13:19:30,160
what a router is and how it functions
18299
13:19:31,140 --> 13:19:32,140
and we discussed static routing which is
18300
13:19:34,560 --> 13:19:35,560
the process of manually creating a
18301
13:19:36,900 --> 13:19:37,900
routing table so in this module we're
18302
13:19:39,720 --> 13:19:40,720
going to Define in more depth
18303
13:19:42,180 --> 13:19:43,180
Dynamic routing which is what allows
18304
13:19:45,416 --> 13:19:46,416
routing just like with DHCP and IP
18305
13:19:49,080 --> 13:19:50,080
addresses to be dynamically up kept
18306
13:19:51,720 --> 13:19:52,720
which is going to allow for
18307
13:19:54,480 --> 13:19:55,480
a much more flexible Network now
18308
13:19:57,900 --> 13:19:58,900
although this title of this entire
18309
13:19:59,880 --> 13:20:00,880
lesson is local area networks in some
18310
13:20:01,800 --> 13:20:02,800
ways we could extend this to wide area
18311
13:20:03,840 --> 13:20:04,840
Networks so we're going to talk about
18312
13:20:05,880 --> 13:20:06,880
Dynamic routing and then we're going to
18313
13:20:07,860 --> 13:20:08,860
talk about two different types of
18314
13:20:10,080 --> 13:20:11,080
dynamic routing these are distant vector
18315
13:20:13,140 --> 13:20:14,140
and Link State now we sort of alluded to
18316
13:20:17,276 --> 13:20:18,276
the difference between these in the
18317
13:20:19,256 --> 13:20:20,256
previous module when I was discussing
18318
13:20:21,060 --> 13:20:22,060
Hops and simply relying on the number of
18319
13:20:24,480 --> 13:20:25,480
hops to get from one place to the other
18320
13:20:26,220 --> 13:20:27,220
versus looking at for instance if one
18321
13:20:30,360 --> 13:20:31,360
link was a dial-up or Broadband or if
18322
13:20:33,720 --> 13:20:34,720
the link was even shut down completely
18323
13:20:36,116 --> 13:20:37,116
and so there are two different types of
18324
13:20:39,660 --> 13:20:40,660
protocol sets we're going to look at
18325
13:20:41,160 --> 13:20:42,160
there are distant Vector protocols these
18326
13:20:44,040 --> 13:20:45,040
are the protocols that allow distant
18327
13:20:46,080 --> 13:20:47,080
Vector routing and then there are link
18328
13:20:48,360 --> 13:20:49,360
State protocols you'll see them listed
18329
13:20:50,700 --> 13:20:51,700
here and we'll talk about each one in
18330
13:20:52,256 --> 13:20:53,256
depth and if the acronyms are already
18331
13:20:54,596 --> 13:20:55,596
starting to freak you out don't worry
18332
13:20:56,400 --> 13:20:57,400
about it what we want to do is just know
18333
13:20:58,860 --> 13:20:59,860
which ones are distance vector and which
18334
13:21:00,900 --> 13:21:01,900
ones are link state so as you can tell
18335
13:21:03,720 --> 13:21:04,720
if you can remember that these two are
18336
13:21:05,820 --> 13:21:06,820
link State you'll be fine for the
18337
13:21:07,436 --> 13:21:08,436
network plus exam which again is
18338
13:21:08,880 --> 13:21:09,880
multiple choice and will ask you to
18339
13:21:10,320 --> 13:21:11,320
recognize it but we'll go over them in a
18340
13:21:12,900 --> 13:21:13,900
little more depth than that
18341
13:21:14,520 --> 13:21:15,520
so Dynamic routing uses a series of
18342
13:21:18,180 --> 13:21:19,180
protocols to establish the routing table
18343
13:21:20,220 --> 13:21:21,220
as opposed to the route add command all
18344
13:21:24,060 --> 13:21:25,060
of the routers pass information about
18345
13:21:26,276 --> 13:21:27,276
themselves along to the other routers
18346
13:21:28,916 --> 13:21:29,916
and they use this information to
18347
13:21:31,980 --> 13:21:32,980
establish a routing table based on
18348
13:21:34,500 --> 13:21:35,500
certain specifics of the other routers
18349
13:21:37,436 --> 13:21:38,436
now there are two different types of
18350
13:21:39,300 --> 13:21:40,300
protocols that are used like I just
18351
13:21:41,040 --> 13:21:42,040
mentioned there are the distance Vector
18352
13:21:43,740 --> 13:21:44,740
protocols which in some ways are older
18353
13:21:48,060 --> 13:21:49,060
and the link State protocols
18354
13:21:50,756 --> 13:21:51,756
which are newer the reason being that
18355
13:21:53,936 --> 13:21:54,936
distance vector
18356
13:21:55,616 --> 13:21:56,616
looks just at the number of miles we
18357
13:21:58,980 --> 13:21:59,980
have to travel and the link state
18358
13:22:02,340 --> 13:22:03,340
also looks at the traffic so it can tell
18359
13:22:06,116 --> 13:22:07,116
us if although we'll have to go further
18360
13:22:09,000 --> 13:22:10,000
miles it's going to be quicker based on
18361
13:22:11,756 --> 13:22:12,756
traffic just like our GPS system
18362
13:22:14,880 --> 13:22:15,880
so
18363
13:22:16,140 --> 13:22:17,140
let's talk about distance Vector first
18364
13:22:18,360 --> 13:22:19,360
in distance Vector routing the routers
18365
13:22:21,300 --> 13:22:22,300
on the network are only aware of the
18366
13:22:23,640 --> 13:22:24,640
routers that they are directly connected
18367
13:22:25,800 --> 13:22:26,800
to so if this is one router let's call
18368
13:22:28,916 --> 13:22:29,916
this router one
18369
13:22:31,436 --> 13:22:32,436
and there's a router two
18370
13:22:34,200 --> 13:22:35,200
a router three
18371
13:22:37,680 --> 13:22:38,680
and a router four router 1 is only aware
18372
13:22:42,416 --> 13:22:43,416
of routers two and three so these
18373
13:22:45,416 --> 13:22:46,416
routers don't know anything about the
18374
13:22:47,040 --> 13:22:48,040
rest of the routers on the network
18375
13:22:48,416 --> 13:22:49,416
unless of course they're directly linked
18376
13:22:50,460 --> 13:22:51,460
now they can share route information
18377
13:22:52,380 --> 13:22:53,380
with these directly connected routers
18378
13:22:54,960 --> 13:22:55,960
but the flow of communication is limited
18379
13:22:57,840 --> 13:22:58,840
as a result the spaces between distance
18380
13:23:01,256 --> 13:23:02,256
Vector routers are known as we just
18381
13:23:04,616 --> 13:23:05,616
talked about this
18382
13:23:06,300 --> 13:23:07,300
hops now each router along these paths
18383
13:23:09,776 --> 13:23:10,776
represent a hop for example a network
18384
13:23:12,840 --> 13:23:13,840
with a five distance Vector routers has
18385
13:23:16,140 --> 13:23:17,140
four hops from the first to last router
18386
13:23:18,960 --> 13:23:19,960
if we have one two three four five
18387
13:23:23,400 --> 13:23:24,400
routers
18388
13:23:24,540 --> 13:23:25,540
there's one two three
18389
13:23:27,000 --> 13:23:28,000
four hops
18390
13:23:28,500 --> 13:23:29,500
it's also important to notice that
18391
13:23:30,840 --> 13:23:31,840
convergence that's the updating of all
18392
13:23:33,960 --> 13:23:34,960
of the information to the router table
18393
13:23:38,820 --> 13:23:39,820
is going to take longer with this set of
18394
13:23:41,160 --> 13:23:42,160
protocols than with link state which
18395
13:23:42,900 --> 13:23:43,900
we'll look at in a second this is
18396
13:23:44,400 --> 13:23:45,400
because the routers don't have the
18397
13:23:46,320 --> 13:23:47,320
knowledge of the entire network so it
18398
13:23:48,416 --> 13:23:49,416
takes longer for them to become aware of
18399
13:23:50,820 --> 13:23:51,820
a change in the network
18400
13:23:52,800 --> 13:23:53,800
so there are four main distance Vector
18401
13:23:55,616 --> 13:23:56,616
protocols that are still in use today
18402
13:23:57,660 --> 13:23:58,660
the first one is called the routing
18403
13:24:00,480 --> 13:24:01,480
information protocol or rip
18404
13:24:03,240 --> 13:24:04,240
routing information protocol version 2
18405
13:24:06,680 --> 13:24:07,680
there's the Border Gateway protocol or
18406
13:24:09,960 --> 13:24:10,960
bgp and finally the enhanced interior
18407
13:24:13,320 --> 13:24:14,320
Gateway routing protocol or eigrp you
18408
13:24:17,400 --> 13:24:18,400
see how these two sort of have some
18409
13:24:19,860 --> 13:24:20,860
similar
18410
13:24:21,140 --> 13:24:22,140
names in them and these two are
18411
13:24:24,180 --> 13:24:25,180
obviously related
18412
13:24:26,580 --> 13:24:27,580
rip or routing information protocol is
18413
13:24:29,936 --> 13:24:30,936
limited to only 15 hops
18414
13:24:33,416 --> 13:24:34,416
originally it required the information
18415
13:24:35,340 --> 13:24:36,340
that updated every 30 seconds
18416
13:24:39,540 --> 13:24:40,540
and on a small Network this wouldn't
18417
13:24:41,400 --> 13:24:42,400
have been a problem but if we're talking
18418
13:24:43,800 --> 13:24:44,800
about a very large Network which is
18419
13:24:45,540 --> 13:24:46,540
where networks went there was going to
18420
13:24:47,820 --> 13:24:48,820
be a large amount of traffic being sent
18421
13:24:49,980 --> 13:24:50,980
between routers at any one time and so
18422
13:24:52,616 --> 13:24:53,616
this became not very useful because of
18423
13:24:55,436 --> 13:24:56,436
speed and also the protocol itself was
18424
13:24:58,020 --> 13:24:59,020
just not very secure and it was very
18425
13:25:01,080 --> 13:25:02,080
vulnerable to attacks and it didn't
18426
13:25:03,540 --> 13:25:04,540
support authentication of any sort now
18427
13:25:06,776 --> 13:25:07,776
remember we want something like
18428
13:25:08,160 --> 13:25:09,160
authentication which would be a username
18429
13:25:10,860 --> 13:25:11,860
and a password so I can make sure the
18430
13:25:12,720 --> 13:25:13,720
router contacted me is the one that I
18431
13:25:14,400 --> 13:25:15,400
wanted to talk with so
18432
13:25:16,680 --> 13:25:17,680
rip 2 came out and this featured
18433
13:25:20,400 --> 13:25:21,400
authentication so it added it for better
18434
13:25:23,340 --> 13:25:24,340
security
18435
13:25:28,140 --> 13:25:29,140
and it also was designed to reduce
18436
13:25:30,980 --> 13:25:31,980
traffic flow
18437
13:25:34,860 --> 13:25:35,860
but it only supported 15 hops because it
18438
13:25:39,660 --> 13:25:40,660
had to be backwards compatible with the
18439
13:25:42,000 --> 13:25:43,000
previous version and since the previous
18440
13:25:44,040 --> 13:25:45,040
version was only 15 hops so was this one
18441
13:25:47,096 --> 13:25:48,096
so again not very useful for very large
18442
13:25:49,916 --> 13:25:50,916
intense networks such as the internet
18443
13:25:57,000 --> 13:25:58,000
now bgp is often associated with the
18444
13:26:01,080 --> 13:26:02,080
internet and the reason is because it
18445
13:26:03,300 --> 13:26:04,300
can be used between internet gateway
18446
13:26:06,060 --> 13:26:07,060
hosts as this name
18447
13:26:08,820 --> 13:26:09,820
implies
18448
13:26:10,616 --> 13:26:11,616
so it examines the routing table and
18449
13:26:13,200 --> 13:26:14,200
decides what is the best route for data
18450
13:26:16,200 --> 13:26:17,200
to travel based on the connections the
18451
13:26:18,840 --> 13:26:19,840
distances and certain addresses
18452
13:26:21,596 --> 13:26:22,596
now the enhanced interior Gateway
18453
13:26:24,116 --> 13:26:25,116
routing protocol are eigrp draws upon
18454
13:26:27,596 --> 13:26:28,596
information that its neighboring routers
18455
13:26:30,360 --> 13:26:31,360
have
18456
13:26:31,740 --> 13:26:32,740
so it would look at all the routers
18457
13:26:35,400 --> 13:26:36,400
that it's a neighbor with now route is
18458
13:26:37,740 --> 13:26:38,740
configured with eigrp would use that
18459
13:26:40,380 --> 13:26:41,380
information to determine the best path
18460
13:26:42,240 --> 13:26:43,240
for data all determined by what all
18461
13:26:45,060 --> 13:26:46,060
these other routers know so that's one
18462
13:26:47,400 --> 13:26:48,400
of the benefits is it went outside of
18463
13:26:49,140 --> 13:26:50,140
itself
18464
13:26:50,220 --> 13:26:51,220
so here's an example of basically
18465
13:26:53,400 --> 13:26:54,400
distance Vector routing the router on
18466
13:26:56,160 --> 13:26:57,160
the top left over here
18467
13:26:59,040 --> 13:27:00,040
has no idea what's going on
18468
13:27:03,596 --> 13:27:04,596
with the routers over here
18469
13:27:06,240 --> 13:27:07,240
it can only make a routing table based
18470
13:27:09,060 --> 13:27:10,060
on the routers it's connected to just
18471
13:27:11,340 --> 13:27:12,340
like the one on the right can only make
18472
13:27:12,960 --> 13:27:13,960
uh
18473
13:27:15,300 --> 13:27:16,300
routing table based on the routers it's
18474
13:27:17,340 --> 13:27:18,340
connected to
18475
13:27:19,560 --> 13:27:20,560
therefore these two are unaware of each
18476
13:27:22,200 --> 13:27:23,200
other's dis of each other's
18477
13:27:24,916 --> 13:27:25,916
existence because they're not connected
18478
13:27:27,300 --> 13:27:28,300
to each other
18479
13:27:28,436 --> 13:27:29,436
now of course they can still communicate
18480
13:27:30,776 --> 13:27:31,776
because there's probably a router some
18481
13:27:33,840 --> 13:27:34,840
place that one of these is connected to
18482
13:27:36,720 --> 13:27:37,720
that will connect them but you can see
18483
13:27:38,640 --> 13:27:39,640
how this is going to make for a lot less
18484
13:27:40,916 --> 13:27:41,916
efficient routing
18485
13:27:44,460 --> 13:27:45,460
so unlike those distance Vector routers
18486
13:27:47,820 --> 13:27:48,820
routers configured with link State
18487
13:27:50,340 --> 13:27:51,340
Protocols are aware of every other
18488
13:27:52,380 --> 13:27:53,380
router on the entire network they use
18489
13:27:54,720 --> 13:27:55,720
each other to build an enormous Network
18490
13:27:57,300 --> 13:27:58,300
map
18491
13:28:02,096 --> 13:28:03,096
and then this network Mac is shared with
18492
13:28:04,680 --> 13:28:05,680
each other unlike distance Vector link
18493
13:28:07,616 --> 13:28:08,616
State routers will update with less
18494
13:28:09,660 --> 13:28:10,660
frequency so there's less traffic on the
18495
13:28:12,596 --> 13:28:13,596
network
18496
13:28:16,916 --> 13:28:17,916
now if a change in the Network's
18497
13:28:20,160 --> 13:28:21,160
topography occurs then they
18498
13:28:22,256 --> 13:28:23,256
automatically update with each other and
18499
13:28:24,240 --> 13:28:25,240
share the map with each other so instead
18500
13:28:26,460 --> 13:28:27,460
of Simply updating at a certain interval
18501
13:28:28,680 --> 13:28:29,680
of time they're going to update whenever
18502
13:28:32,400 --> 13:28:33,400
there's a change
18503
13:28:34,256 --> 13:28:35,256
now though this seems like link state
18504
13:28:36,540 --> 13:28:37,540
has a better set of protocols link State
18505
13:28:39,000 --> 13:28:40,000
routers also require a more powerful
18506
13:28:40,980 --> 13:28:41,980
system components such as better Ram
18507
13:28:44,276 --> 13:28:45,276
cetera then distance vector and that's
18508
13:28:46,980 --> 13:28:47,980
why we still see distance Vector used
18509
13:28:48,840 --> 13:28:49,840
quite a bit in some cases we don't need
18510
13:28:51,360 --> 13:28:52,360
link state
18511
13:28:52,800 --> 13:28:53,800
so it offers quicker convergence
18512
13:28:55,860 --> 13:28:56,860
as a result of this automatically
18513
13:28:58,020 --> 13:28:59,020
updating but this also means it needs
18514
13:28:59,936 --> 13:29:00,936
more power
18515
13:29:01,080 --> 13:29:02,080
so there are two protocols I want to go
18516
13:29:02,820 --> 13:29:03,820
over with this the first is
18517
13:29:05,040 --> 13:29:06,040
the open shortest path first or ospf and
18518
13:29:08,460 --> 13:29:09,460
the second is the intermediate system to
18519
13:29:10,860 --> 13:29:11,860
intermediate system protocol these are
18520
13:29:13,680 --> 13:29:14,680
really similar and they both use a
18521
13:29:16,256 --> 13:29:17,256
shortest path algorithm
18522
13:29:19,560 --> 13:29:20,560
to determine the shortest way for the
18523
13:29:21,540 --> 13:29:22,540
data to travel however we're generally
18524
13:29:23,820 --> 13:29:24,820
going to see this one the OS PF on
18525
13:29:28,080 --> 13:29:29,080
medium networks and Isis
18526
13:29:31,500 --> 13:29:32,500
on larger Networks
18527
13:29:33,840 --> 13:29:34,840
another benefit of this is because it
18528
13:29:35,936 --> 13:29:36,936
knows all of the routers on the network
18529
13:29:38,880 --> 13:29:39,880
it doesn't just think about distance it
18530
13:29:41,460 --> 13:29:42,460
also looks at what type of connections
18531
13:29:43,740 --> 13:29:44,740
we have it looks at the state of the
18532
13:29:45,900 --> 13:29:46,900
links and therefore it can make give you
18533
13:29:48,416 --> 13:29:49,416
in some cases the best route available
18534
13:29:51,720 --> 13:29:52,720
not just based on the number of hops but
18535
13:29:54,416 --> 13:29:55,416
on a lot of different factors so here we
18536
13:29:57,776 --> 13:29:58,776
can see what a link State protocol might
18537
13:30:01,200 --> 13:30:02,200
look like the two different groups
18538
13:30:03,116 --> 13:30:04,116
aren't connected directly however
18539
13:30:05,580 --> 13:30:06,580
they're both aware of the entire network
18540
13:30:07,916 --> 13:30:08,916
layout as you can see if we imagine that
18541
13:30:10,980 --> 13:30:11,980
this was a map inside of the router and
18542
13:30:13,560 --> 13:30:14,560
then they can then share that Network
18543
13:30:15,360 --> 13:30:16,360
layout with all of their other routers
18544
13:30:18,480 --> 13:30:19,480
in this way they create a massive
18545
13:30:20,460 --> 13:30:21,460
Network
18546
13:30:21,416 --> 13:30:22,416
and massive routing map on their Network
18547
13:30:24,180 --> 13:30:25,180
and can communicate much more
18548
13:30:26,220 --> 13:30:27,220
efficiently and quickly
18549
13:30:28,740 --> 13:30:29,740
so we've just talked about Dynamic
18550
13:30:31,200 --> 13:30:32,200
routing which means basically that the
18551
13:30:33,360 --> 13:30:34,360
routers
18552
13:30:35,096 --> 13:30:36,096
builds
18553
13:30:38,276 --> 13:30:39,276
their own network map
18554
13:30:43,256 --> 13:30:44,256
or routing table
18555
13:30:46,436 --> 13:30:47,436
this is much more efficient than static
18556
13:30:48,960 --> 13:30:49,960
routing we also compare distance Vector
18557
13:30:52,020 --> 13:30:53,020
to link State again distance Vector is
18558
13:30:54,960 --> 13:30:55,960
focused very much on Hops and isn't
18559
13:30:57,360 --> 13:30:58,360
aware of all of the devices on the
18560
13:30:59,460 --> 13:31:00,460
network only direct connections
18561
13:31:04,200 --> 13:31:05,200
link State on the other hand
18562
13:31:06,596 --> 13:31:07,596
looks at other features
18563
13:31:09,000 --> 13:31:10,000
so for instance traffic latency Etc
18564
13:31:12,720 --> 13:31:13,720
and has a huge Network map
18565
13:31:16,380 --> 13:31:17,380
of course the downside is that distance
18566
13:31:19,320 --> 13:31:20,320
Vector is going to be a lot more
18567
13:31:21,840 --> 13:31:22,840
efficient with the resources it has in
18568
13:31:24,180 --> 13:31:25,180
the router than link state which
18569
13:31:25,436 --> 13:31:26,436
requires uh perhaps better or more
18570
13:31:29,580 --> 13:31:30,580
powerful system components
18571
13:31:31,560 --> 13:31:32,560
we also finally talked about the
18572
13:31:33,720 --> 13:31:34,720
different protocols rip rip version 2
18573
13:31:36,500 --> 13:31:37,500
bgp and eigrp were our disinspectors and
18574
13:31:41,400 --> 13:31:42,400
our two link States again ospf is for
18575
13:31:44,220 --> 13:31:45,220
medium Networks
18576
13:31:45,776 --> 13:31:46,776
and Isis
18577
13:31:48,660 --> 13:31:49,660
or Isis is for larger Networks
18578
13:31:52,680 --> 13:31:53,680
we still see all of these used
18579
13:31:56,220 --> 13:31:57,220
but these are newer
18580
13:31:58,200 --> 13:31:59,200
perhaps a faster at convergence
18581
13:32:04,560 --> 13:32:05,560
although perhaps not the most ideal for
18582
13:32:07,800 --> 13:32:08,800
our Network or necessary for the network
18583
13:32:09,540 --> 13:32:10,540
we have
18584
13:32:11,460 --> 13:32:12,460
so now that we've talked about switching
18585
13:32:13,436 --> 13:32:14,436
and routing I want to talk about
18586
13:32:15,180 --> 13:32:16,180
something which is a little not so much
18587
13:32:18,660 --> 13:32:19,660
complex but allows for more organization
18588
13:32:21,180 --> 13:32:22,180
within our Network which is called vlans
18589
13:32:23,820 --> 13:32:24,820
or virtual lands
18590
13:32:30,600 --> 13:32:31,600
[Music]
18591
13:32:46,500 --> 13:32:47,500
welcome to module 8 lesson 4A igp and
18592
13:32:50,160 --> 13:32:51,160
EGP
18593
13:32:53,040 --> 13:32:54,040
all right so we're going to look uh this
18594
13:32:54,840 --> 13:32:55,840
is an overview really to put things in
18595
13:32:57,060 --> 13:32:58,060
context a dynamic router protocols
18596
13:32:59,540 --> 13:33:00,540
interior Gateway protocols autonomous
18597
13:33:02,456 --> 13:33:03,456
systems
18598
13:33:03,800 --> 13:33:04,800
bgp in brief obviously how the protocol
18599
13:33:07,020 --> 13:33:08,020
works much
18600
13:33:09,720 --> 13:33:10,720
so we can classify Dynamic writing
18601
13:33:11,880 --> 13:33:12,880
protocols into interior uh and exterior
18602
13:33:16,740 --> 13:33:17,740
the interior protocols these are the
18603
13:33:19,020 --> 13:33:20,020
ones that we'll be using mostly As
18604
13:33:21,540 --> 13:33:22,540
Network Engineers on a day-to-day basis
18605
13:33:23,580 --> 13:33:24,580
unless we end up working for an ISP an
18606
13:33:26,700 --> 13:33:27,700
internet service provider
18607
13:33:29,400 --> 13:33:30,400
so in order to understand what we mean
18608
13:33:31,380 --> 13:33:32,380
by the inside of a network we actually
18609
13:33:32,936 --> 13:33:33,936
need to understand the term autonomous
18610
13:33:35,400 --> 13:33:36,400
system which we generally shorten as an
18611
13:33:37,616 --> 13:33:38,616
m2as
18612
13:33:40,616 --> 13:33:41,616
so an AES is one or more networks that
18613
13:33:43,020 --> 13:33:44,020
are governed by a single Administration
18614
13:33:44,756 --> 13:33:45,756
so it could be a company Network or a
18615
13:33:47,880 --> 13:33:48,880
large company Network and you can see
18616
13:33:50,220 --> 13:33:51,220
here we have um three different asses
18617
13:33:53,880 --> 13:33:54,880
now these as could actually all belong
18618
13:33:56,276 --> 13:33:57,276
to the same company and inside you've
18619
13:33:58,680 --> 13:33:59,680
got a different administrative domains
18620
13:34:00,596 --> 13:34:01,596
for example the large Cloud as200 could
18621
13:34:04,020 --> 13:34:05,020
all be running ospf and you could have
18622
13:34:06,480 --> 13:34:07,480
bought a company on the top left there
18623
13:34:08,580 --> 13:34:09,580
that um is running ergrp or just has a
18624
13:34:12,540 --> 13:34:13,540
different set of administrative
18625
13:34:13,916 --> 13:34:14,916
principle principles and roles in this
18626
13:34:17,340 --> 13:34:18,340
particular example you can see as100 on
18627
13:34:20,520 --> 13:34:21,520
the top left and as300 on the top right
18628
13:34:23,220 --> 13:34:24,220
are actually isps
18629
13:34:25,680 --> 13:34:26,680
these are internet service providers
18630
13:34:29,360 --> 13:34:30,360
so
18631
13:34:30,900 --> 13:34:31,900
um even though it says here that the as
18632
13:34:33,360 --> 13:34:34,360
within is under the control of a single
18633
13:34:36,116 --> 13:34:37,116
Authority you could have various teams
18634
13:34:38,456 --> 13:34:39,456
managing different parts of the network
18635
13:34:40,080 --> 13:34:41,080
however it's all under the same
18636
13:34:42,080 --> 13:34:43,080
administrative control
18637
13:34:45,840 --> 13:34:46,840
as is actually defined in the one of the
18638
13:34:48,240 --> 13:34:49,240
rfcs 1930 if you wanted to Google that
18639
13:34:51,240 --> 13:34:52,240
but it'd probably be a fairly long and
18640
13:34:52,916 --> 13:34:53,916
boring read I think
18641
13:34:54,540 --> 13:34:55,540
according to the definition of the as
18642
13:34:56,720 --> 13:34:57,720
it's a set of routers under a single
18643
13:34:59,220 --> 13:35:00,220
technical Administration uses an igp
18644
13:35:02,820 --> 13:35:03,820
interior Gateway protocol and common
18645
13:35:05,220 --> 13:35:06,220
metrics to Route packets within the as
18646
13:35:08,880 --> 13:35:09,880
you would you generally use an exterior
18647
13:35:11,756 --> 13:35:12,756
Gateway protocol an EGP to Route package
18648
13:35:14,520 --> 13:35:15,520
to other autonomous systems
18649
13:35:19,020 --> 13:35:20,020
The ROC says that the as a single and
18650
13:35:21,776 --> 13:35:22,776
clearly defined routing policy which
18651
13:35:23,700 --> 13:35:24,700
makes sense if your company is running
18652
13:35:26,340 --> 13:35:27,340
the administration
18653
13:35:28,980 --> 13:35:29,980
now routers within an AES use an igp
18654
13:35:31,500 --> 13:35:32,500
which I've already said so here's um
18655
13:35:34,980 --> 13:35:35,980
an image from Microsoft's tech net you
18656
13:35:38,520 --> 13:35:39,520
can see there's two different autonomous
18657
13:35:41,220 --> 13:35:42,220
systems here they're running an igp and
18658
13:35:44,160 --> 13:35:45,160
is here we Gateway protocol doing all
18659
13:35:46,020 --> 13:35:47,020
their ospf routing whatever they need to
18660
13:35:49,020 --> 13:35:50,020
do and then in order to communicate with
18661
13:35:51,660 --> 13:35:52,660
another autonomous system it's running
18662
13:35:53,700 --> 13:35:54,700
in the EGP between the two border
18663
13:35:57,020 --> 13:35:58,020
routers there
18664
13:36:01,080 --> 13:36:02,080
you can further and divide igps into
18665
13:36:05,400 --> 13:36:06,400
distance Vector link state or hybrid
18666
13:36:08,456 --> 13:36:09,456
some of the common ones are rip or rip
18667
13:36:10,560 --> 13:36:11,560
version two
18668
13:36:11,820 --> 13:36:12,820
ospf is an advanced writing protocol
18669
13:36:14,400 --> 13:36:15,400
Isis
18670
13:36:15,980 --> 13:36:16,980
ergrp is a hybrid which is uses parts of
18671
13:36:20,820 --> 13:36:21,820
the distance vector and part of the link
18672
13:36:23,340 --> 13:36:24,340
state igrp is um
18673
13:36:26,756 --> 13:36:27,756
pretty redundant now to be honest it's
18674
13:36:28,916 --> 13:36:29,916
not very rarely used because of its
18675
13:36:31,500 --> 13:36:32,500
aging it's not very flexible at all
18676
13:36:35,276 --> 13:36:36,276
uh exterior Gateway protocol is a
18677
13:36:37,860 --> 13:36:38,860
routing protocol used to route between a
18678
13:36:39,720 --> 13:36:40,720
s's which we've already mentioned if
18679
13:36:41,936 --> 13:36:42,936
you're going to route between autonomous
18680
13:36:43,560 --> 13:36:44,560
systems it's referred to as inter as
18681
13:36:46,560 --> 13:36:47,560
routing
18682
13:36:49,560 --> 13:36:50,560
so an example is bgp which is mentioned
18683
13:36:52,616 --> 13:36:53,616
in the syllabus is used for inter as
18684
13:36:55,020 --> 13:36:56,020
routing so it's a route between
18685
13:36:57,436 --> 13:36:58,436
as1 2 and 3 here we've got an exterior
18686
13:37:01,616 --> 13:37:02,616
Gateway routing protocol there is
18687
13:37:04,020 --> 13:37:05,020
actually a writing protocol called
18688
13:37:06,300 --> 13:37:07,300
interior bgp which you can use to Route
18689
13:37:09,900 --> 13:37:10,900
within an autonomous system and I think
18690
13:37:12,900 --> 13:37:13,900
that's mentioned in the syllabus in any
18691
13:37:15,060 --> 13:37:16,060
detail but um bgp is used to route
18692
13:37:19,080 --> 13:37:20,080
between autonomous systems exterior bgp
18693
13:37:24,300 --> 13:37:25,300
now each as is actually given a unique
18694
13:37:26,820 --> 13:37:27,820
number you have to apply for these
18695
13:37:29,400 --> 13:37:30,400
numbers to your service provider or your
18696
13:37:31,860 --> 13:37:32,860
internet registry whoever that may be
18697
13:37:37,560 --> 13:37:38,560
and as I said I've already said this it
18698
13:37:40,080 --> 13:37:41,080
needs to be a unique Asm
18699
13:37:42,360 --> 13:37:43,360
and the ASN is a actually supplied by
18700
13:37:46,380 --> 13:37:47,380
the internet assigned numbers Authority
18701
13:37:48,480 --> 13:37:49,480
and they'll split the numbers between
18702
13:37:50,640 --> 13:37:51,640
whoever governs the numbers within your
18703
13:37:53,096 --> 13:37:54,096
country
18704
13:37:54,540 --> 13:37:55,540
uh all organizations within the network
18705
13:37:56,880 --> 13:37:57,880
don't need ASN the Network that has a
18706
13:37:59,580 --> 13:38:00,580
single connection to an ISP and a single
18707
13:38:01,560 --> 13:38:02,560
prefix
18708
13:38:02,640 --> 13:38:03,640
which is a subnet mask doesn't need the
18709
13:38:05,580 --> 13:38:06,580
ASM because the prefix of that network
18710
13:38:07,256 --> 13:38:08,256
is managed by the internet service
18711
13:38:08,756 --> 13:38:09,756
provider so you may not actually need to
18712
13:38:11,220 --> 13:38:12,220
worry about any of the exterior routing
18713
13:38:13,140 --> 13:38:14,140
you could be really low SPF all through
18714
13:38:15,540 --> 13:38:16,540
your network send your traffic to your
18715
13:38:18,300 --> 13:38:19,300
internet service provider and let that
18716
13:38:20,276 --> 13:38:21,276
let them take care of any exterior
18717
13:38:22,616 --> 13:38:23,616
routing
18718
13:38:24,616 --> 13:38:25,616
bgp exterior Gateway protocol and it
18719
13:38:28,256 --> 13:38:29,256
routes packets between the Asus which
18720
13:38:30,720 --> 13:38:31,720
I've already said here is an example of
18721
13:38:33,060 --> 13:38:34,060
some different ases and on the bottom
18722
13:38:34,916 --> 13:38:35,916
you've got as1
18723
13:38:36,360 --> 13:38:37,360
which has the um prefix
18724
13:38:40,096 --> 13:38:41,096
192.020 and the subnet mask of Slash 24.
18725
13:38:45,900 --> 13:38:46,900
24 bits
18726
13:38:49,080 --> 13:38:50,080
according to the RFC and bgp is an
18727
13:38:52,680 --> 13:38:53,680
inter-autonomous system router protocol
18728
13:38:54,480 --> 13:38:55,480
it actually uses TCP so it uses a
18729
13:38:57,776 --> 13:38:58,776
reliable transport method as opposed to
18730
13:39:00,300 --> 13:39:01,300
other protocols it listens on TC Port
18731
13:39:03,240 --> 13:39:04,240
what TCP Port 179
18732
13:39:05,880 --> 13:39:06,880
and you can see we've caught a captured
18733
13:39:08,096 --> 13:39:09,096
a bgp message with a a packet capture
18734
13:39:11,340 --> 13:39:12,340
program looks like Wireshark there's an
18735
13:39:13,200 --> 13:39:14,200
open message and you can see the
18736
13:39:14,400 --> 13:39:15,400
destination Port there is 179 and it's
18737
13:39:17,340 --> 13:39:18,340
using TCP
18738
13:39:21,480 --> 13:39:22,480
current version is four if you could
18739
13:39:23,580 --> 13:39:24,580
look further down inside the bgp packet
18740
13:39:26,580 --> 13:39:27,580
it says version four
18741
13:39:29,276 --> 13:39:30,276
that's the current version in use today
18742
13:39:33,956 --> 13:39:34,956
all right so CompTIA they actually list
18743
13:39:35,936 --> 13:39:36,936
it as a hybrid protocol I'm not sure why
18744
13:39:38,160 --> 13:39:39,160
they do that
18745
13:39:39,416 --> 13:39:40,416
it's a path Vector routing protocol
18746
13:39:42,660 --> 13:39:43,660
so you can see the paths here as1 at the
18747
13:39:46,380 --> 13:39:47,380
bottom is sending the nlris network
18748
13:39:50,400 --> 13:39:51,400
layer reachability information I.E how
18749
13:39:53,340 --> 13:39:54,340
to get to that particular Network and
18750
13:39:55,020 --> 13:39:56,020
prefix
18751
13:39:56,756 --> 13:39:57,756
router 3 appends its path which is as3
18752
13:40:00,300 --> 13:40:01,300
and then when the
18753
13:40:02,400 --> 13:40:03,400
um
18754
13:40:03,660 --> 13:40:04,660
network
18755
13:40:04,936 --> 13:40:05,936
192020 is sent to as5 it's appended with
18756
13:40:09,180 --> 13:40:10,180
the paths four three and one
18757
13:40:11,276 --> 13:40:12,276
as a reply is sent the different paths
18758
13:40:13,980 --> 13:40:14,980
are removed so as4 will remove path four
18759
13:40:17,400 --> 13:40:18,400
and send it to three we'll remove three
18760
13:40:19,500 --> 13:40:20,500
and back over to one
18761
13:40:24,660 --> 13:40:25,660
all right so we've covered an overview
18762
13:40:26,936 --> 13:40:27,936
of dynamic protocols interior routing
18763
13:40:29,756 --> 13:40:30,756
protocols what an as is bgp that's all
18764
13:40:33,776 --> 13:40:34,776
for now thanks for watching
18765
13:40:40,660 --> 13:40:41,660
[Music]
18766
13:40:57,060 --> 13:40:58,060
log into module 8 lesson 4B routing
18767
13:40:59,756 --> 13:41:00,756
loops
18768
13:41:01,560 --> 13:41:02,560
but look at what a writing loop is and
18769
13:41:03,660 --> 13:41:04,660
distance Vector writing protocols
18770
13:41:05,520 --> 13:41:06,520
splitter Eisen and poison reverse which
18771
13:41:08,820 --> 13:41:09,820
are there a couple of the solutions to
18772
13:41:10,616 --> 13:41:11,616
prevent
18773
13:41:11,640 --> 13:41:12,640
routing loops on a network layer 3 loops
18774
13:41:16,256 --> 13:41:17,256
so writing Loop is a network problem
18775
13:41:18,416 --> 13:41:19,416
where a pucky gets routed between two or
18776
13:41:20,580 --> 13:41:21,580
more routers endlessly
18777
13:41:22,680 --> 13:41:23,680
now this is a different solution to
18778
13:41:24,776 --> 13:41:25,776
layer 2 Loops where we have a spanning
18779
13:41:28,680 --> 13:41:29,680
tree protocol
18780
13:41:30,180 --> 13:41:31,180
and some Advanced versions of that that
18781
13:41:33,000 --> 13:41:34,000
uh there to stop layer 2 packet
18782
13:41:35,340 --> 13:41:36,340
circulated because Layer Two packets
18783
13:41:37,080 --> 13:41:38,080
don't have a time to live value
18784
13:41:41,096 --> 13:41:42,096
so this happens when the writing table
18785
13:41:42,956 --> 13:41:43,956
has incorrect information
18786
13:41:45,660 --> 13:41:46,660
as we know during the writing process
18787
13:41:48,720 --> 13:41:49,720
routers forward packets to various
18788
13:41:50,756 --> 13:41:51,756
destinations these are based on the
18789
13:41:52,740 --> 13:41:53,740
entries in the routing table now if one
18790
13:41:55,200 --> 13:41:56,200
of these entries is incorrect for
18791
13:41:56,936 --> 13:41:57,936
example a network goes down
18792
13:41:58,980 --> 13:41:59,980
then a routing Loop can occur so here's
18793
13:42:02,340 --> 13:42:03,340
an example I'll go into more detail in a
18794
13:42:05,040 --> 13:42:06,040
bit but for today's advertising
18795
13:42:08,360 --> 13:42:09,360
192.168.20 which advertises out of both
18796
13:42:11,880 --> 13:42:12,880
interfaces there it goes to router BM
18797
13:42:15,000 --> 13:42:16,000
router C both of which advertise to
18798
13:42:17,880 --> 13:42:18,880
router a
18799
13:42:19,320 --> 13:42:20,320
now rights array unfortunately has two
18800
13:42:22,560 --> 13:42:23,560
ways to send the packet to router
18801
13:42:27,416 --> 13:42:28,416
um or to to paths to see
18802
13:42:29,880 --> 13:42:30,880
uh 192.16820 which isn't necessarily a
18803
13:42:33,300 --> 13:42:34,300
problem however what router a does
18804
13:42:36,480 --> 13:42:37,480
advertised the fact that it knows how to
18805
13:42:38,640 --> 13:42:39,640
get to that Network to router C to
18806
13:42:41,160 --> 13:42:42,160
router B which then forwards it to
18807
13:42:43,500 --> 13:42:44,500
router D now router D is hearing from
18808
13:42:47,700 --> 13:42:48,700
other routers that they know or they
18809
13:42:49,860 --> 13:42:50,860
have a route to get to 192.1682.0
18810
13:42:54,776 --> 13:42:55,776
now if that Network goes down router d
18811
13:42:58,800 --> 13:42:59,800
will be sending packets to that Network
18812
13:43:01,400 --> 13:43:02,400
either to router C or router B because
18813
13:43:04,500 --> 13:43:05,500
it's heard from those routers that it
18814
13:43:07,560 --> 13:43:08,560
knows how to reach that Network
18815
13:43:09,720 --> 13:43:10,720
so this is how our writing Loop can
18816
13:43:13,140 --> 13:43:14,140
um cause havoc on your network
18817
13:43:15,720 --> 13:43:16,720
so go go to a bit more detail with
18818
13:43:17,640 --> 13:43:18,640
another example here obviously have a
18819
13:43:19,680 --> 13:43:20,680
detrimental effect
18820
13:43:21,740 --> 13:43:22,740
increases packet loss utilization of the
18821
13:43:25,020 --> 13:43:26,020
links CPU utilization on your routers
18822
13:43:27,540 --> 13:43:28,540
because it has to process
18823
13:43:29,456 --> 13:43:30,456
every time the packet's received
18824
13:43:32,936 --> 13:43:33,936
so in distance Vector protocols slow
18825
13:43:36,180 --> 13:43:37,180
convergence causes routing Loops this is
18826
13:43:38,640 --> 13:43:39,640
when other parts of the network are
18827
13:43:41,276 --> 13:43:42,276
stabilizing their routing tables slower
18828
13:43:43,500 --> 13:43:44,500
than other parts of the network
18829
13:43:46,080 --> 13:43:47,080
any change in the network is updated in
18830
13:43:48,360 --> 13:43:49,360
the writing tables
18831
13:43:51,480 --> 13:43:52,480
so during the process the routing tables
18832
13:43:54,000 --> 13:43:55,000
have inconsistent entries due to slow
18833
13:43:57,240 --> 13:43:58,240
convergence this could be due to
18834
13:43:58,800 --> 13:43:59,800
bandwidth or pros and processing speeds
18835
13:44:01,680 --> 13:44:02,680
on your router
18836
13:44:04,740 --> 13:44:05,740
the network is said to have converged
18837
13:44:06,480 --> 13:44:07,480
when all writing tables are consistent
18838
13:44:08,276 --> 13:44:09,276
so this means every router's got the
18839
13:44:10,800 --> 13:44:11,800
same picture of the network and they all
18840
13:44:12,596 --> 13:44:13,596
agree on which networks are where
18841
13:44:16,140 --> 13:44:17,140
so here we've got router C advertising
18842
13:44:18,360 --> 13:44:19,360
the 1011 Network
18843
13:44:22,080 --> 13:44:23,080
when the net was converged all routers
18844
13:44:24,116 --> 13:44:25,116
will agree that that Network exists and
18845
13:44:26,220 --> 13:44:27,220
they will agree on how to reach that
18846
13:44:28,560 --> 13:44:29,560
Network so a will send it out of the
18847
13:44:31,140 --> 13:44:32,140
right hand interface B out to the right
18848
13:44:33,116 --> 13:44:34,116
hand interface and then C is directly
18849
13:44:35,456 --> 13:44:36,456
connected
18850
13:44:37,740 --> 13:44:38,740
now if this network goes down or the
18851
13:44:40,740 --> 13:44:41,740
interface goes down
18852
13:44:42,900 --> 13:44:43,900
relative c will remove that route to the
18853
13:44:46,320 --> 13:44:47,320
network from his writing table but
18854
13:44:48,596 --> 13:44:49,596
before this update is the center out to
18855
13:44:50,580 --> 13:44:51,580
be
18856
13:44:51,240 --> 13:44:52,240
router B sends a periodic update to
18857
13:44:54,000 --> 13:44:55,000
router C saying it knows how to reach
18858
13:44:56,220 --> 13:44:57,220
the 10110 Network
18859
13:45:00,720 --> 13:45:01,720
so this update makes for how to c think
18860
13:45:02,880 --> 13:45:03,880
that router B has an alternative path to
18861
13:45:05,220 --> 13:45:06,220
get there
18862
13:45:06,116 --> 13:45:07,116
obviously through some of the series of
18863
13:45:08,456 --> 13:45:09,456
routers it doesn't
18864
13:45:10,560 --> 13:45:11,560
uh have a picture of the entire network
18865
13:45:12,680 --> 13:45:13,680
and well it's got this directly
18866
13:45:15,116 --> 13:45:16,116
connected Network and it believes what
18867
13:45:16,680 --> 13:45:17,680
it has from other routers
18868
13:45:19,200 --> 13:45:20,200
so it will mark this uh route to get to
18869
13:45:22,680 --> 13:45:23,680
the 10110 Network as reachable through
18870
13:45:26,220 --> 13:45:27,220
router B
18871
13:45:29,220 --> 13:45:30,220
a periodic update from RTC will contain
18872
13:45:31,800 --> 13:45:32,800
that Network which we've already said
18873
13:45:33,616 --> 13:45:34,616
router B assumes it knows how to reach
18874
13:45:35,880 --> 13:45:36,880
that Network mentioned in the update
18875
13:45:39,660 --> 13:45:40,660
now when router B receives a packet
18876
13:45:42,180 --> 13:45:43,180
destined to the 10110 Network it will
18877
13:45:44,276 --> 13:45:45,276
forward it to router C
18878
13:45:47,880 --> 13:45:48,880
when Route 60 receives the packet it
18879
13:45:49,740 --> 13:45:50,740
sends it back to router B and this is
18880
13:45:51,360 --> 13:45:52,360
where the loop is happening
18881
13:45:53,820 --> 13:45:54,820
so unlike switching Loops the in writing
18882
13:45:57,300 --> 13:45:58,300
like the packet will last until the time
18883
13:45:59,756 --> 13:46:00,756
to live value which is TTL in the packet
18884
13:46:02,700 --> 13:46:03,700
header reaches zero
18885
13:46:04,740 --> 13:46:05,740
so you can see the time to live fields
18886
13:46:07,740 --> 13:46:08,740
in this particular packet here which is
18887
13:46:09,480 --> 13:46:10,480
a bgp packet capture
18888
13:46:13,040 --> 13:46:14,040
once the time to live value reaches zero
18889
13:46:15,956 --> 13:46:16,956
the routers then drop that packet
18890
13:46:19,740 --> 13:46:20,740
and disinfected protocols we've got a
18891
13:46:21,956 --> 13:46:22,956
couple of solutions
18892
13:46:23,720 --> 13:46:24,720
splitterizing and poison reverse so this
18893
13:46:26,880 --> 13:46:27,880
is split Horizon the rule is that if an
18894
13:46:29,756 --> 13:46:30,756
interface learns a particular route it
18895
13:46:32,340 --> 13:46:33,340
doesn't advertise that route back out of
18896
13:46:34,200 --> 13:46:35,200
the same interface now this causes
18897
13:46:37,020 --> 13:46:38,020
problems when you come to configure a
18898
13:46:39,480 --> 13:46:40,480
hub and spoke Network and there's ways
18899
13:46:41,820 --> 13:46:42,820
around it which we're not going to cover
18900
13:46:42,900 --> 13:46:43,900
here with ergrp and ospf in particular
18901
13:46:46,380 --> 13:46:47,380
you can change this rule or turn this
18902
13:46:48,776 --> 13:46:49,776
rule off and set of ways to get around
18903
13:46:52,020 --> 13:46:53,020
it so routing works
18904
13:46:54,060 --> 13:46:55,060
so router a learns about rata C from
18905
13:46:57,776 --> 13:46:58,776
router B what it won't do then is
18906
13:46:59,756 --> 13:47:00,756
advertise the network back out of the
18907
13:47:01,436 --> 13:47:02,436
same interface to router B because this
18908
13:47:03,900 --> 13:47:04,900
would breach the split Horizon Rule and
18909
13:47:06,180 --> 13:47:07,180
basically route and the networks
18910
13:47:07,860 --> 13:47:08,860
attached to router C can be reached via
18911
13:47:10,256 --> 13:47:11,256
B so it doesn't need to be re-advertised
18912
13:47:12,480 --> 13:47:13,480
back to router B and cause confusion
18913
13:47:15,776 --> 13:47:16,776
poison reverses a form of split Horizon
18914
13:47:18,776 --> 13:47:19,776
it uses a method to use um known as
18915
13:47:22,500 --> 13:47:23,500
route posing angle poison reverse it
18916
13:47:25,200 --> 13:47:26,200
allows the router to set a distance to
18917
13:47:27,180 --> 13:47:28,180
the network as Infinity this is for the
18918
13:47:30,360 --> 13:47:31,360
um
18919
13:47:30,900 --> 13:47:31,900
how many hops for example in rip
18920
13:47:33,956 --> 13:47:34,956
this allows the network to converge so
18921
13:47:36,956 --> 13:47:37,956
perhaps you've had some instability
18922
13:47:39,116 --> 13:47:40,116
the network attached to router E network
18923
13:47:41,820 --> 13:47:42,820
5 has gone down so router e will quickly
18924
13:47:44,456 --> 13:47:45,456
advertise that with an infinite distance
18925
13:47:46,560 --> 13:47:47,560
which is known as rat poisoning
18926
13:47:50,640 --> 13:47:51,640
so I've looked at Loops distance Vector
18927
13:47:52,800 --> 13:47:53,800
routing protocols bit Horizon poison
18928
13:47:55,256 --> 13:47:56,256
reverse that's all for now thanks for
18929
13:47:57,776 --> 13:47:58,776
watching
18930
13:48:03,760 --> 13:48:04,760
[Music]
18931
13:48:11,520 --> 13:48:12,520
foreign
18932
13:48:24,560 --> 13:48:25,560
networks vlans and sohos
18933
13:48:29,220 --> 13:48:30,220
so we finished talking about switching
18934
13:48:31,380 --> 13:48:32,380
and routing how networks communicate
18935
13:48:34,860 --> 13:48:35,860
with one another and so now we want to
18936
13:48:37,080 --> 13:48:38,080
talk about two other terms that we see a
18937
13:48:40,200 --> 13:48:41,200
lot when we talk about local area
18938
13:48:41,520 --> 13:48:42,520
networks and they're important to know
18939
13:48:43,200 --> 13:48:44,200
for the network plus exam
18940
13:48:45,300 --> 13:48:46,300
the first is called VLAN or virtual
18941
13:48:48,480 --> 13:48:49,480
local area network it has to do with
18942
13:48:51,180 --> 13:48:52,180
segmenting a physical local area network
18943
13:48:54,180 --> 13:48:55,180
into two or more virtual or logical
18944
13:48:57,776 --> 13:48:58,776
local area networks and we're also going
18945
13:49:00,776 --> 13:49:01,776
to discuss what they do and how we
18946
13:49:03,776 --> 13:49:04,776
Define memberships in vlans since this
18947
13:49:07,200 --> 13:49:08,200
is not a physical distinction but a
18948
13:49:09,956 --> 13:49:10,956
logical one we're also going to discuss
18949
13:49:12,596 --> 13:49:13,596
a Soho Network also called a small
18950
13:49:16,080 --> 13:49:17,080
office home office Network we've
18951
13:49:18,116 --> 13:49:19,116
probably seen this term in the past
18952
13:49:19,560 --> 13:49:20,560
because we deal with it when we talk
18953
13:49:21,540 --> 13:49:22,540
about Soho routers which are those
18954
13:49:24,660 --> 13:49:25,660
routers like the d-links and the Linksys
18955
13:49:26,820 --> 13:49:27,820
that you have at your home that allow
18956
13:49:29,580 --> 13:49:30,580
you to get for instance wireless access
18957
13:49:31,256 --> 13:49:32,256
although
18958
13:49:33,116 --> 13:49:34,116
these provide many different things
18959
13:49:34,916 --> 13:49:35,916
they're distinct from a regular router a
18960
13:49:38,096 --> 13:49:39,096
Soho router because a regular router
18961
13:49:40,740 --> 13:49:41,740
just does routing whereas a Soho router
18962
13:49:42,900 --> 13:49:43,900
does several different things now that's
18963
13:49:44,936 --> 13:49:45,936
an example of why a small office home
18964
13:49:46,800 --> 13:49:47,800
office is so such an important term when
18965
13:49:49,680 --> 13:49:50,680
it comes to network Plus
18966
13:49:51,660 --> 13:49:52,660
so virtual local area networks or vlans
18967
13:49:55,380 --> 13:49:56,380
are a type of local area network
18968
13:49:57,480 --> 13:49:58,480
configuration they're actually somewhat
18969
13:50:00,360 --> 13:50:01,360
of a misnomer though the word virtual is
18970
13:50:03,180 --> 13:50:04,180
really the focus of the name they're
18971
13:50:05,880 --> 13:50:06,880
really more segmented than virtual VLAN
18972
13:50:09,776 --> 13:50:10,776
can be described or defined as a group
18973
13:50:12,540 --> 13:50:13,540
of computers that are connected to one
18974
13:50:14,880 --> 13:50:15,880
another although they function as though
18975
13:50:17,820 --> 13:50:18,820
they are on different networks even
18976
13:50:19,616 --> 13:50:20,616
though they sometimes aren't so the
18977
13:50:22,560 --> 13:50:23,560
computers that are segmented together
18978
13:50:24,720 --> 13:50:25,720
are usually ones that are in a same
18979
13:50:27,720 --> 13:50:28,720
Department as the others for example we
18980
13:50:30,596 --> 13:50:31,596
might have an office building with four
18981
13:50:34,500 --> 13:50:35,500
floors
18982
13:50:37,320 --> 13:50:38,320
and the encounting employees could be on
18983
13:50:41,096 --> 13:50:42,096
every floor
18984
13:50:45,116 --> 13:50:46,116
a VLAN would allow them to all be
18985
13:50:48,416 --> 13:50:49,416
connected to one another
18986
13:50:50,580 --> 13:50:51,580
even though they're really
18987
13:50:53,880 --> 13:50:54,880
sort of sharing the network
18988
13:50:57,720 --> 13:50:58,720
with every other department in other
18989
13:51:00,116 --> 13:51:01,116
words
18990
13:51:01,140 --> 13:51:02,140
if we had the accountants and then let's
18991
13:51:03,720 --> 13:51:04,720
say the managers they would all be
18992
13:51:06,240 --> 13:51:07,240
connected to the same physical Network
18993
13:51:09,180 --> 13:51:10,180
in the building but we could segment
18994
13:51:11,700 --> 13:51:12,700
them into separate virtual local area
18995
13:51:15,240 --> 13:51:16,240
networks so that way they can
18996
13:51:17,276 --> 13:51:18,276
communicate with one another and other
18997
13:51:19,140 --> 13:51:20,140
folks can't communicate with them
18998
13:51:22,080 --> 13:51:23,080
they would therefore think that they
18999
13:51:25,436 --> 13:51:26,436
were connected physically to one another
19000
13:51:27,360 --> 13:51:28,360
or all plugged into the same switch even
19001
13:51:31,200 --> 13:51:32,200
though were you really using four
19002
13:51:33,416 --> 13:51:34,416
different switches one for each floor
19003
13:51:37,140 --> 13:51:38,140
now there's some very clear benefits to
19004
13:51:39,956 --> 13:51:40,956
having VLAN set up
19005
13:51:42,240 --> 13:51:43,240
first the security is increased this is
19006
13:51:45,300 --> 13:51:46,300
because when we segment a network
19007
13:51:49,320 --> 13:51:50,320
there are virtual boundaries and that
19008
13:51:52,080 --> 13:51:53,080
makes attacking the entire network very
19009
13:51:54,360 --> 13:51:55,360
unlikely it also makes sure that
19010
13:51:57,180 --> 13:51:58,180
accounting people are going to have a
19011
13:51:58,860 --> 13:51:59,860
harder time getting into the management
19012
13:52:01,436 --> 13:52:02,436
people's information
19013
13:52:03,300 --> 13:52:04,300
so again even though they're physically
19014
13:52:05,756 --> 13:52:06,756
connected all the same we're giving them
19015
13:52:08,580 --> 13:52:09,580
a virtual segmentation so that they are
19016
13:52:11,580 --> 13:52:12,580
separate and therefore it's a slightly
19017
13:52:13,860 --> 13:52:14,860
more secure
19018
13:52:15,300 --> 13:52:16,300
they also increase the performance by
19019
13:52:18,660 --> 13:52:19,660
freeing up bandwidth and reducing and
19020
13:52:21,300 --> 13:52:22,300
splitting up traffic from the network if
19021
13:52:23,880 --> 13:52:24,880
accounting for instance uses a lot of
19022
13:52:26,520 --> 13:52:27,520
bandwidth and management doesn't well we
19023
13:52:29,640 --> 13:52:30,640
don't want management to suffer because
19024
13:52:31,616 --> 13:52:32,616
accounting is using QuickBooks and the
19025
13:52:33,900 --> 13:52:34,900
servers so much therefore by segmenting
19026
13:52:36,720 --> 13:52:37,720
it we can make sure all of the traffic
19027
13:52:39,000 --> 13:52:40,000
that accounting is using is staying on
19028
13:52:41,880 --> 13:52:42,880
their segment and management performance
19029
13:52:45,180 --> 13:52:46,180
doesn't suffer as a result
19030
13:52:48,300 --> 13:52:49,300
we can also group users that often
19031
13:52:50,700 --> 13:52:51,700
communicate and share data and so this
19032
13:52:53,520 --> 13:52:54,520
network becomes far more organized this
19033
13:52:56,340 --> 13:52:57,340
is not just from security and
19034
13:52:57,840 --> 13:52:58,840
performance perspectives organization is
19035
13:53:00,596 --> 13:53:01,596
just from a logistical perspective as
19036
13:53:02,640 --> 13:53:03,640
well I can put someone in a VLAN and
19037
13:53:04,740 --> 13:53:05,740
automatically they're going to have all
19038
13:53:06,840 --> 13:53:07,840
the benefits that come with being in
19039
13:53:09,116 --> 13:53:10,116
that segmented area independent of their
19040
13:53:11,700 --> 13:53:12,700
physical location
19041
13:53:14,700 --> 13:53:15,700
finally it also makes the
19042
13:53:16,500 --> 13:53:17,500
administrator's job a lot more easier
19043
13:53:18,596 --> 13:53:19,596
because when everything is segmented up
19044
13:53:21,000 --> 13:53:22,000
things become easier to deal with I
19045
13:53:23,880 --> 13:53:24,880
don't have to create a specific set of
19046
13:53:27,240 --> 13:53:28,240
policies or security for one individual
19047
13:53:30,480 --> 13:53:31,480
when I can simply
19048
13:53:33,180 --> 13:53:34,180
uh put them into a VLAN and let it all
19049
13:53:35,580 --> 13:53:36,580
sort of work itself out
19050
13:53:37,680 --> 13:53:38,680
so here's an example of what a VLAN
19051
13:53:40,616 --> 13:53:41,616
might look like as you can see there are
19052
13:53:42,596 --> 13:53:43,596
four floors to the building with
19053
13:53:44,040 --> 13:53:45,040
computers on each of them and the
19054
13:53:45,840 --> 13:53:46,840
computers are all connected to the same
19055
13:53:47,700 --> 13:53:48,700
network I very much simplified this in
19056
13:53:50,936 --> 13:53:51,936
fact we would probably have uh switch on
19057
13:53:54,240 --> 13:53:55,240
every floor
19058
13:53:55,500 --> 13:53:56,500
remember this would be called the idfs
19059
13:53:59,880 --> 13:54:00,880
and then they would all come together
19060
13:54:01,860 --> 13:54:02,860
like we see here in one Central MDF but
19061
13:54:06,180 --> 13:54:07,180
for all intensive purposes they're all
19062
13:54:08,520 --> 13:54:09,520
connected to the same physical Network
19063
13:54:10,880 --> 13:54:11,880
however we only want the accounting
19064
13:54:14,040 --> 13:54:15,040
employees to share data with themselves
19065
13:54:16,800 --> 13:54:17,800
not with the graphic designers or the
19066
13:54:19,320 --> 13:54:20,320
marketing folks and we want them to have
19067
13:54:21,596 --> 13:54:22,596
their own segmented Network as well
19068
13:54:24,180 --> 13:54:25,180
so with VLAN we can actually segment out
19069
13:54:27,956 --> 13:54:28,956
the
19070
13:54:29,520 --> 13:54:30,520
counting folks into their own virtual
19071
13:54:32,456 --> 13:54:33,456
Network even though they're on the same
19072
13:54:34,320 --> 13:54:35,320
physical Network
19073
13:54:36,720 --> 13:54:37,720
the same could go for the graphic design
19074
13:54:38,936 --> 13:54:39,936
folks and the marketing folks they're
19075
13:54:42,480 --> 13:54:43,480
all split into segments with similar
19076
13:54:44,756 --> 13:54:45,756
employees and we would actually give
19077
13:54:46,680 --> 13:54:47,680
these vlans numbers for instance VLAN 1
19078
13:54:49,560 --> 13:54:50,560
2
19079
13:54:51,596 --> 13:54:52,596
and three
19080
13:54:55,380 --> 13:54:56,380
now there are three different ways that
19081
13:54:57,660 --> 13:54:58,660
VLAN membership can be assigned a
19082
13:55:00,416 --> 13:55:01,416
membership is a way that the device is
19083
13:55:02,160 --> 13:55:03,160
assigned to that specific VLAN for
19084
13:55:04,616 --> 13:55:05,616
instance the one two or three that we
19085
13:55:06,240 --> 13:55:07,240
just mentioned the first method involves
19086
13:55:10,040 --> 13:55:11,040
protocol-based vlans in this way
19087
13:55:12,540 --> 13:55:13,540
computers are assigned to vlans using
19088
13:55:15,720 --> 13:55:16,720
networking protocols that are in place
19089
13:55:18,000 --> 13:55:19,000
such as the IP address the IP number is
19090
13:55:21,480 --> 13:55:22,480
only used to determine the membership
19091
13:55:23,160 --> 13:55:24,160
but has nothing to do with the routing
19092
13:55:25,740 --> 13:55:26,740
of the VLAN Network so for instance we
19093
13:55:28,560 --> 13:55:29,560
could say all IP addresses from 1 to 100
19094
13:55:31,916 --> 13:55:32,916
are on a specific VLAN and all the ones
19095
13:55:35,040 --> 13:55:36,040
from 101 to 200 are in another
19096
13:55:39,060 --> 13:55:40,060
another thing we can do is what's called
19097
13:55:41,456 --> 13:55:42,456
Port based vlans
19098
13:55:43,380 --> 13:55:44,380
this requires that ports on the network
19099
13:55:45,660 --> 13:55:46,660
switch are assigned to specific vlans so
19100
13:55:49,140 --> 13:55:50,140
as you saw previously we had uh
19101
13:55:52,320 --> 13:55:53,320
accounting and marketing and Graphics
19102
13:55:55,020 --> 13:55:56,020
all in sort of different
19103
13:55:57,416 --> 13:55:58,416
um physical locations but they were all
19104
13:55:59,220 --> 13:56:00,220
plugged up to a central switch
19105
13:56:01,800 --> 13:56:02,800
so what we would say is for instance
19106
13:56:04,200 --> 13:56:05,200
any computers plugged up to supports one
19107
13:56:07,436 --> 13:56:08,436
through three are in VLAN one and the
19108
13:56:10,680 --> 13:56:11,680
ports plugged up to four and five or in
19109
13:56:13,380 --> 13:56:14,380
two and six and seven are three now
19110
13:56:15,840 --> 13:56:16,840
remember a lot of switches can have
19111
13:56:17,400 --> 13:56:18,400
perhaps 200 ports so this can get a
19112
13:56:20,400 --> 13:56:21,400
little complex
19113
13:56:23,700 --> 13:56:24,700
finally there's mac address based vlans
19114
13:56:27,416 --> 13:56:28,416
in this way you've heard of the physical
19115
13:56:31,256 --> 13:56:32,256
address and when you know that we can
19116
13:56:33,416 --> 13:56:34,416
use this to actually filter out
19117
13:56:35,880 --> 13:56:36,880
um using a what's called an ACL or
19118
13:56:38,276 --> 13:56:39,276
Access Control lists certain Mac
19119
13:56:39,956 --> 13:56:40,956
addresses from a wireless access point
19120
13:56:42,000 --> 13:56:43,000
well it works the same way with a VLAN
19121
13:56:44,160 --> 13:56:45,160
depending on the Mac address of the
19122
13:56:46,560 --> 13:56:47,560
computer that is being connected it will
19123
13:56:49,800 --> 13:56:50,800
automatically place it into a specific
19124
13:56:51,840 --> 13:56:52,840
VLAN of course the benefit with this is
19125
13:56:54,416 --> 13:56:55,416
because the MAC address is the physical
19126
13:56:56,276 --> 13:56:57,276
address of the computer and is always
19127
13:56:58,916 --> 13:56:59,916
hardwired onto that computer
19128
13:57:01,020 --> 13:57:02,020
I can move the computer into any
19129
13:57:03,360 --> 13:57:04,360
different port and it can get any
19130
13:57:05,220 --> 13:57:06,220
different IP address and it'll always
19131
13:57:06,956 --> 13:57:07,956
remain in the same virtual local area
19132
13:57:10,860 --> 13:57:11,860
network
19133
13:57:13,860 --> 13:57:14,860
now the other term we want to talk about
19134
13:57:15,900 --> 13:57:16,900
is a Soho Network or a small office home
19135
13:57:20,456 --> 13:57:21,456
office Network this is generally
19136
13:57:23,160 --> 13:57:24,160
speaking as the name implies a smaller
19137
13:57:26,580 --> 13:57:27,580
home office Network that serves between
19138
13:57:29,456 --> 13:57:30,456
one to ten users on the network now you
19139
13:57:32,340 --> 13:57:33,340
can have more users or less users
19140
13:57:34,436 --> 13:57:35,436
although I guess you wouldn't have less
19141
13:57:36,116 --> 13:57:37,116
users than one but generally speaking
19142
13:57:38,756 --> 13:57:39,756
it's really going to designate a very
19143
13:57:40,980 --> 13:57:41,980
small Network although they're smaller
19144
13:57:44,276 --> 13:57:45,276
in physical size and generally smaller
19145
13:57:46,740 --> 13:57:47,740
than the number of users they're going
19146
13:57:48,480 --> 13:57:49,480
to accommodate the network in the same
19147
13:57:50,880 --> 13:57:51,880
sort of way meaning we're going to use
19148
13:57:52,256 --> 13:57:53,256
some of the same protocols and devices
19149
13:57:54,596 --> 13:57:55,596
they're just going to be built
19150
13:57:55,860 --> 13:57:56,860
differently because they don't need to
19151
13:57:57,416 --> 13:57:58,416
be as powerful
19152
13:57:58,980 --> 13:57:59,980
so for instance here is a small office
19153
13:58:02,096 --> 13:58:03,096
home office Network you have two PCS in
19154
13:58:05,040 --> 13:58:06,040
it perhaps I have one in the living room
19155
13:58:06,900 --> 13:58:07,900
or one in the bedroom and one in my home
19156
13:58:09,540 --> 13:58:10,540
office and maybe even we have a laptop
19157
13:58:12,660 --> 13:58:13,660
as well
19158
13:58:14,040 --> 13:58:15,040
so maybe we have three different
19159
13:58:15,480 --> 13:58:16,480
computers ones for the kids one's for my
19160
13:58:18,060 --> 13:58:19,060
wife and one's for me
19161
13:58:19,860 --> 13:58:20,860
now
19162
13:58:21,240 --> 13:58:22,240
we have what's called a small office
19163
13:58:24,000 --> 13:58:25,000
home office router
19164
13:58:25,800 --> 13:58:26,800
now it's called just a router to many of
19165
13:58:28,800 --> 13:58:29,800
us but really this is a small office
19166
13:58:30,720 --> 13:58:31,720
home office router because it does
19167
13:58:32,096 --> 13:58:33,096
several things it has a built-in DHCP
19168
13:58:34,980 --> 13:58:35,980
server
19169
13:58:36,180 --> 13:58:37,180
for a lot of us it also is Wireless
19170
13:58:40,200 --> 13:58:41,200
so it's a wireless access point or WAP
19171
13:58:43,756 --> 13:58:44,756
it's also has uh plugs on the back so in
19172
13:58:47,456 --> 13:58:48,456
some ways it acts as a switch for us
19173
13:58:49,380 --> 13:58:50,380
although that's built into a router so
19174
13:58:51,116 --> 13:58:52,116
I'm not going to write that separately
19175
13:58:52,320 --> 13:58:53,320
it does something called Network address
19176
13:58:55,640 --> 13:58:56,640
translation which allows the IP address
19177
13:58:58,916 --> 13:58:59,916
coming from our internet service
19178
13:59:00,660 --> 13:59:01,660
provider on our modem which might be
19179
13:59:03,240 --> 13:59:04,240
let's say
19180
13:59:07,340 --> 13:59:08,340
126.43.17.3 to be shared among three
19181
13:59:11,040 --> 13:59:12,040
different uh internal devices
19182
13:59:14,880 --> 13:59:15,880
so that way when information comes in
19183
13:59:18,596 --> 13:59:19,596
from the internet it knows which device
19184
13:59:21,000 --> 13:59:22,000
to send it out to
19185
13:59:23,700 --> 13:59:24,700
and also does a couple other things for
19186
13:59:25,800 --> 13:59:26,800
instance it might have a firewall
19187
13:59:28,500 --> 13:59:29,500
and to do some other stuff we've
19188
13:59:30,416 --> 13:59:31,416
mentioned as well
19189
13:59:32,160 --> 13:59:33,160
no matter and it might even allow for
19190
13:59:34,680 --> 13:59:35,680
vlans actually
19191
13:59:36,416 --> 13:59:37,416
but no matter you can see that this one
19192
13:59:38,520 --> 13:59:39,520
device is taking on several devices that
19193
13:59:41,520 --> 13:59:42,520
we've talked about previously
19194
13:59:43,740 --> 13:59:44,740
this was your only uh experience with a
19195
13:59:47,340 --> 13:59:48,340
router and you might think all routers
19196
13:59:49,256 --> 13:59:50,256
operate this way in fact they don't we
19197
13:59:51,240 --> 13:59:52,240
just call it a router because that's
19198
13:59:53,756 --> 13:59:54,756
probably the most important function it
19199
13:59:55,500 --> 13:59:56,500
does which allows us to get out to the
19200
13:59:57,480 --> 13:59:58,480
network
19201
13:59:58,436 --> 13:59:59,436
but there's not floors and floors and
19202
14:00:01,320 --> 14:00:02,320
floors of stuff going on here and this
19203
14:00:03,540 --> 14:00:04,540
router wouldn't do very well
19204
14:00:05,580 --> 14:00:06,580
is because it's not built to if I tried
19205
14:00:07,740 --> 14:00:08,740
plugging a hundred computers up to it so
19206
14:00:10,616 --> 14:00:11,616
the real important thing here is as you
19207
14:00:13,080 --> 14:00:14,080
go forward in your career you'll
19208
14:00:15,360 --> 14:00:16,360
probably be seeing more and more of this
19209
14:00:16,916 --> 14:00:17,916
and if you're going to be supporting
19210
14:00:18,000 --> 14:00:19,000
homes or really small businesses then
19211
14:00:20,820 --> 14:00:21,820
you want to know that perhaps they don't
19212
14:00:22,500 --> 14:00:23,500
need a separate switch and router they
19213
14:00:24,660 --> 14:00:25,660
just need one device that being said if
19214
14:00:27,000 --> 14:00:28,000
a company is growing really fast perhaps
19215
14:00:29,820 --> 14:00:30,820
they need to purchase a separate switch
19216
14:00:31,680 --> 14:00:32,680
that then plugs into the router the
19217
14:00:33,900 --> 14:00:34,900
switch therefore can help work with
19218
14:00:36,060 --> 14:00:37,060
traffic internally of the network and
19219
14:00:38,340 --> 14:00:39,340
the router will help get the information
19220
14:00:40,256 --> 14:00:41,256
out onto the network
19221
14:00:42,180 --> 14:00:43,180
but it's important again to realize that
19222
14:00:44,220 --> 14:00:45,220
even though this is a small office home
19223
14:00:46,256 --> 14:00:47,256
office or Soho that's not the area or
19224
14:00:49,020 --> 14:00:50,020
the geographic location remember that's
19225
14:00:51,116 --> 14:00:52,116
just the name of this type of network
19226
14:00:52,700 --> 14:00:53,700
that it's going to have all the same
19227
14:00:55,380 --> 14:00:56,380
principles apply it's just the devices
19228
14:00:57,720 --> 14:00:58,720
might be smaller and less able to handle
19229
14:01:01,020 --> 14:01:02,020
a lot of people
19230
14:01:03,416 --> 14:01:04,416
so we've talked about uh virtual local
19231
14:01:07,200 --> 14:01:08,200
area network which is basically
19232
14:01:09,300 --> 14:01:10,300
segmenting
19233
14:01:13,160 --> 14:01:14,160
a lan or local area network into several
19234
14:01:16,800 --> 14:01:17,800
logical partitions
19235
14:01:19,436 --> 14:01:20,436
but physically everything is exactly the
19236
14:01:22,916 --> 14:01:23,916
same
19237
14:01:25,256 --> 14:01:26,256
we talked about how we do the
19238
14:01:26,756 --> 14:01:27,756
memberships for these we can do it based
19239
14:01:29,096 --> 14:01:30,096
on the port it's plugged into
19240
14:01:31,200 --> 14:01:32,200
we can also do it based on the Mac
19241
14:01:33,540 --> 14:01:34,540
address
19242
14:01:34,680 --> 14:01:35,680
or based on the protocol
19243
14:01:36,660 --> 14:01:37,660
which in some ways would be linked to
19244
14:01:38,456 --> 14:01:39,456
the IP address
19245
14:01:40,200 --> 14:01:41,200
finally we talked about a Soho Network
19246
14:01:43,020 --> 14:01:44,020
or small office home office Network
19247
14:01:44,700 --> 14:01:45,700
which the real reason we want to know
19248
14:01:46,500 --> 14:01:47,500
that is because the devices are going to
19249
14:01:49,740 --> 14:01:50,740
be less powerful
19250
14:01:53,220 --> 14:01:54,220
okay
19251
14:01:54,060 --> 14:01:55,060
and they're going to sort of converge
19252
14:01:57,720 --> 14:01:58,720
meaning that we're going to have a
19253
14:01:59,820 --> 14:02:00,820
wireless access point that's also a
19254
14:02:01,680 --> 14:02:02,680
router that's also a DHCP server whereas
19255
14:02:04,560 --> 14:02:05,560
in a large Network we would separate all
19256
14:02:06,360 --> 14:02:07,360
of this out
19257
14:02:08,400 --> 14:02:09,400
so that's sort of
19258
14:02:10,500 --> 14:02:11,500
finishes our discussion on local area
19259
14:02:12,596 --> 14:02:13,596
networks and lands the next lesson is
19260
14:02:15,776 --> 14:02:16,776
going to talk about wide area networks
19261
14:02:18,480 --> 14:02:19,480
or wans which we've already talked about
19262
14:02:20,820 --> 14:02:21,820
slightly when dealing with routing but
19263
14:02:22,980 --> 14:02:23,980
we're going to talk about that in a bit
19264
14:02:24,776 --> 14:02:25,776
more depth
19265
14:02:26,700 --> 14:02:27,700
vlans and drugs
19266
14:02:28,800 --> 14:02:29,800
we'll be doing some Labs on this as we
19267
14:02:31,500 --> 14:02:32,500
go through the course so don't worry
19268
14:02:33,776 --> 14:02:34,776
um if it doesn't sink in straight away
19269
14:02:36,416 --> 14:02:37,416
a VLAN is a virtual local area network
19270
14:02:38,880 --> 14:02:39,880
so it's not something you can see by
19271
14:02:41,340 --> 14:02:42,340
physically looking at the network you'd
19272
14:02:42,900 --> 14:02:43,900
have to look at the configuration of the
19273
14:02:45,240 --> 14:02:46,240
switches
19274
14:02:46,740 --> 14:02:47,740
it defines a broadcast domain in the
19275
14:02:48,720 --> 14:02:49,720
layer 2 Network
19276
14:02:50,160 --> 14:02:51,160
so just the same as
19277
14:02:53,220 --> 14:02:54,220
local area network using the switch
19278
14:02:56,456 --> 14:02:57,456
the switch will forward broadcasts
19279
14:02:59,456 --> 14:03:00,456
however if you have two vlans on a
19280
14:03:01,980 --> 14:03:02,980
switch for example the one on the top
19281
14:03:03,660 --> 14:03:04,660
right diagram there
19282
14:03:05,456 --> 14:03:06,456
the broadcast will stop as far as the
19283
14:03:07,436 --> 14:03:08,436
VLAN reason is you need a layer 3 device
19284
14:03:10,916 --> 14:03:11,916
which is normally a router in order to
19285
14:03:13,880 --> 14:03:14,880
send information from one network to
19286
14:03:16,500 --> 14:03:17,500
another so virtual local area network
19287
14:03:18,680 --> 14:03:19,680
for all intents and purposes it follows
19288
14:03:21,956 --> 14:03:22,956
the same rule as a normal Network or
19289
14:03:24,300 --> 14:03:25,300
subnet
19290
14:03:27,240 --> 14:03:28,240
so you can separate broadcast domains
19291
14:03:30,240 --> 14:03:31,240
even though it's on the same physical
19292
14:03:31,616 --> 14:03:32,616
switch by configuring a layer 2.
19293
14:03:36,776 --> 14:03:37,776
a VLAN is a logical division of switch
19294
14:03:39,300 --> 14:03:40,300
ports so if you had 20
19295
14:03:42,240 --> 14:03:43,240
switch ports physically on the switch
19296
14:03:44,400 --> 14:03:45,400
you could in theory have 20 different
19297
14:03:47,880 --> 14:03:48,880
um
19298
14:03:48,660 --> 14:03:49,660
devices each in its own VLAN
19299
14:03:52,500 --> 14:03:53,500
you need a router to pass packets
19300
14:03:54,116 --> 14:03:55,116
between vlans some switches actually
19301
14:03:56,580 --> 14:03:57,580
come with a
19302
14:03:57,956 --> 14:03:58,956
a writing module that you can insert
19303
14:04:01,080 --> 14:04:02,080
which is a bit beyond CCNA level to be
19304
14:04:05,340 --> 14:04:06,340
honest just for your own information so
19305
14:04:08,640 --> 14:04:09,640
vlans can spun multiple physical
19306
14:04:10,320 --> 14:04:11,320
switches
19307
14:04:12,360 --> 14:04:13,360
so we've got switch one two and three
19308
14:04:14,340 --> 14:04:15,340
here and you can see we've got a couple
19309
14:04:16,860 --> 14:04:17,860
of different vlans configured
19310
14:04:19,860 --> 14:04:20,860
best to have all hosts in the same VLAN
19311
14:04:22,320 --> 14:04:23,320
on the same subnet that's all really
19312
14:04:24,956 --> 14:04:25,956
wanted to say on that particular subject
19313
14:04:26,580 --> 14:04:27,580
but it's just the best
19314
14:04:28,740 --> 14:04:29,740
um idea
19315
14:04:30,300 --> 14:04:31,300
no need for a variety to communicate if
19316
14:04:34,380 --> 14:04:35,380
all the devices are all on the same VLAN
19317
14:04:40,256 --> 14:04:41,256
some of the benefits or why would you
19318
14:04:42,060 --> 14:04:43,060
bother logical separation just gives you
19319
14:04:44,400 --> 14:04:45,400
better security
19320
14:04:45,680 --> 14:04:46,680
helps with the broadcast issues if you
19321
14:04:48,900 --> 14:04:49,900
do up on better utilization of your
19322
14:04:51,480 --> 14:04:52,480
bandwidth
19323
14:04:53,416 --> 14:04:54,416
Avila marking obviously it has to be
19324
14:04:55,916 --> 14:04:56,916
some way if you're chopping your network
19325
14:04:57,900 --> 14:04:58,900
into vlans for the VLAN to identify
19326
14:05:00,480 --> 14:05:01,480
itself
19327
14:05:01,740 --> 14:05:02,740
vendors use different approaches for
19328
14:05:03,720 --> 14:05:04,720
example Cisco created ISL into switch
19329
14:05:06,480 --> 14:05:07,480
link which is a proprietary for Cisco
19330
14:05:09,416 --> 14:05:10,416
devices they've actually moved away from
19331
14:05:11,640 --> 14:05:12,640
ISL now though many of their switches
19332
14:05:13,800 --> 14:05:14,800
still support it and they moved on to
19333
14:05:15,720 --> 14:05:16,720
IEEE standard 802.1q
19334
14:05:19,020 --> 14:05:20,020
called frame tagging frame tagging
19335
14:05:21,480 --> 14:05:22,480
inserts a 32-bit tag field into the
19336
14:05:23,640 --> 14:05:24,640
original frame
19337
14:05:26,220 --> 14:05:27,220
so concept of a native VLAN is something
19338
14:05:29,160 --> 14:05:30,160
you should be familiar with as a Cisco
19339
14:05:30,776 --> 14:05:31,776
engineer
19340
14:05:32,040 --> 14:05:33,040
a native VLAN on Cisco devices certainly
19341
14:05:36,256 --> 14:05:37,256
is all allocated to VLAN one by default
19342
14:05:41,936 --> 14:05:42,936
all devices in a VLAN will be assigned
19343
14:05:44,040 --> 14:05:45,040
to VLAN 1 unless you configure and then
19344
14:05:46,916 --> 14:05:47,916
to be in a different VLAN
19345
14:05:48,840 --> 14:05:49,840
so traffic on a VLAN on that on the
19346
14:05:51,660 --> 14:05:52,660
native VLAN is not tagged it's not given
19347
14:05:53,936 --> 14:05:54,936
the 802.1 Q tagging
19348
14:05:56,880 --> 14:05:57,880
well the reason is it uh we have it is
19349
14:05:59,580 --> 14:06:00,580
it allows the switch to communicate with
19350
14:06:01,320 --> 14:06:02,320
the device that doesn't understand
19351
14:06:02,520 --> 14:06:03,520
802.1q
19352
14:06:05,340 --> 14:06:06,340
it is a security risk which we'll cover
19353
14:06:07,560 --> 14:06:08,560
later on
19354
14:06:10,560 --> 14:06:11,560
vlr membership so you can assign VLAN
19355
14:06:14,096 --> 14:06:15,096
devices or ports to a VLAN statically as
19356
14:06:18,240 --> 14:06:19,240
a network administrator
19357
14:06:19,860 --> 14:06:20,860
it can be dynamic based upon device Mac
19358
14:06:22,140 --> 14:06:23,140
address
19359
14:06:23,340 --> 14:06:24,340
switch ports are assigned to vlans and
19360
14:06:25,916 --> 14:06:26,916
then devices plug into the physical
19361
14:06:27,480 --> 14:06:28,480
ports
19362
14:06:28,616 --> 14:06:29,616
access ports connect to network hosts
19363
14:06:33,596 --> 14:06:34,596
a network hosts connect to access ports
19364
14:06:35,700 --> 14:06:36,700
it works both way around that sentence
19365
14:06:38,096 --> 14:06:39,096
if you want to connect to another switch
19366
14:06:39,660 --> 14:06:40,660
and you're using multiple vlans then
19367
14:06:42,000 --> 14:06:43,000
these connections are known as trunk
19368
14:06:44,456 --> 14:06:45,456
ports
19369
14:06:45,840 --> 14:06:46,840
so trunk ports uh will connect more than
19370
14:06:49,500 --> 14:06:50,500
one VLAN which is connecting more than
19371
14:06:52,320 --> 14:06:53,320
one VLAN together
19372
14:06:55,256 --> 14:06:56,256
so a special Port type carries data from
19373
14:06:57,596 --> 14:06:58,596
multiple vlans it can use ISL although
19374
14:07:00,300 --> 14:07:01,300
that's pretty much been depreciated now
19375
14:07:02,520 --> 14:07:03,520
so you shouldn't be looking at it for
19376
14:07:04,080 --> 14:07:05,080
the CISCO exams at least
19377
14:07:07,080 --> 14:07:08,080
frame tag in is transparent to end hosts
19378
14:07:10,020 --> 14:07:11,020
so the tag is attached by the switch
19379
14:07:12,596 --> 14:07:13,596
sent to another switch and before it
19380
14:07:14,520 --> 14:07:15,520
reaches the end hosts the tag is
19381
14:07:16,800 --> 14:07:17,800
actually removed
19382
14:07:18,360 --> 14:07:19,360
trunkport modes we can manually set the
19383
14:07:22,140 --> 14:07:23,140
interface to trunk with the command
19384
14:07:24,060 --> 14:07:25,060
switch Port mode trunk
19385
14:07:26,400 --> 14:07:27,400
trunk modes include on which is manually
19386
14:07:29,160 --> 14:07:30,160
set the interface to trunk off you can
19387
14:07:31,800 --> 14:07:32,800
tell it to never become a trunk
19388
14:07:34,200 --> 14:07:35,200
Auto silently wait for a request to
19389
14:07:36,596 --> 14:07:37,596
become a trunk desirable which means
19390
14:07:39,480 --> 14:07:40,480
actively seek to become a trunk or no
19391
14:07:42,596 --> 14:07:43,596
negotiate you'll cover these commands
19392
14:07:45,720 --> 14:07:46,720
in detail when you come to do the CCNA I
19393
14:07:48,900 --> 14:07:49,900
probably won't be doing
19394
14:07:50,276 --> 14:07:51,276
um
19395
14:07:50,820 --> 14:07:51,820
covering these commands and how to
19396
14:07:52,500 --> 14:07:53,500
configure them for the primer
19397
14:07:55,500 --> 14:07:56,500
configuring a VLAN you need to manually
19398
14:07:57,840 --> 14:07:58,840
add the ports to vlans
19399
14:07:59,936 --> 14:08:00,936
and you need to set your ports to trunk
19400
14:08:03,000 --> 14:08:04,000
so here's a configuration I've just done
19401
14:08:06,116 --> 14:08:07,116
one side because the configuration is
19402
14:08:07,800 --> 14:08:08,800
the same for both switches
19403
14:08:10,200 --> 14:08:11,200
I've created VLAN 5 in config mode by
19404
14:08:13,740 --> 14:08:14,740
typing VLAN 5.
19405
14:08:15,660 --> 14:08:16,660
I've given it a name called RND so you
19406
14:08:19,500 --> 14:08:20,500
can name your vlans it probably makes it
19407
14:08:21,840 --> 14:08:22,840
easy for you to manage interface fast
19408
14:08:23,880 --> 14:08:24,880
ethernet zero slash one I've created
19409
14:08:25,916 --> 14:08:26,916
switch Port access VLAN 5. so this is
19410
14:08:29,936 --> 14:08:30,936
telling the port that it's a switch Port
19411
14:08:32,580 --> 14:08:33,580
layer 2 and it and the device is belongs
19412
14:08:36,180 --> 14:08:37,180
to VLAN file that's connected to it
19413
14:08:38,756 --> 14:08:39,756
I've gone on to my fast ethernet 0-15
19414
14:08:41,540 --> 14:08:42,540
switchboard trunk encapsulation.1q
19415
14:08:45,180 --> 14:08:46,180
to tell it what encapsulation to use
19416
14:08:47,340 --> 14:08:48,340
that won't work on a 2960 switch because
19417
14:08:50,116 --> 14:08:51,116
2960 will only recognize.monkey
19418
14:08:53,580 --> 14:08:54,580
and I've told it to become a trump port
19419
14:08:57,720 --> 14:08:58,720
okay so you'll be labbing some of this
19420
14:08:59,580 --> 14:09:00,580
up later on but for now that's the end
19421
14:09:01,980 --> 14:09:02,980
thanks for listening
19422
14:09:07,400 --> 14:09:08,400
[Music]
19423
14:09:27,616 --> 14:09:28,616
wide area networks implementation and
19424
14:09:31,436 --> 14:09:32,436
administration
19425
14:09:33,240 --> 14:09:34,240
in the previous lesson we discussed
19426
14:09:36,000 --> 14:09:37,000
local area networks or lands these were
19427
14:09:39,540 --> 14:09:40,540
networks that were restricted to a
19428
14:09:41,700 --> 14:09:42,700
specific single geographic location now
19429
14:09:45,116 --> 14:09:46,116
in this lesson we're going to talk more
19430
14:09:47,160 --> 14:09:48,160
about wide area networks or wans we're
19431
14:09:51,180 --> 14:09:52,180
going to Define them and talk about how
19432
14:09:53,580 --> 14:09:54,580
they compare to local area Networks
19433
14:09:56,936 --> 14:09:57,936
so we're first going to define a Wan
19434
14:10:00,300 --> 14:10:01,300
which we've talked about in general
19435
14:10:01,980 --> 14:10:02,980
before and then we're going to identify
19436
14:10:04,140 --> 14:10:05,140
some of the steps we would take to
19437
14:10:05,700 --> 14:10:06,700
implement one uh specifically some of
19438
14:10:08,096 --> 14:10:09,096
the things that make it different from a
19439
14:10:09,900 --> 14:10:10,900
local area network or LAN
19440
14:10:12,416 --> 14:10:13,416
finally we want to identify some of the
19441
14:10:15,060 --> 14:10:16,060
administrative tasks that go along with
19442
14:10:17,820 --> 14:10:18,820
or that challenge us as Wan
19443
14:10:20,096 --> 14:10:21,096
administrators specifically backup and
19444
14:10:23,520 --> 14:10:24,520
security
19445
14:10:24,900 --> 14:10:25,900
so a Wan is a wide area network and
19446
14:10:28,916 --> 14:10:29,916
though it functions very similarly to a
19447
14:10:31,740 --> 14:10:32,740
lan it is different in that it's the way
19448
14:10:35,340 --> 14:10:36,340
it's set up and the way it's connected
19449
14:10:37,616 --> 14:10:38,616
when is uh Network that's not restricted
19450
14:10:41,220 --> 14:10:42,220
to a single geographic location like a
19451
14:10:44,276 --> 14:10:45,276
lan in fact it's often made up of
19452
14:10:46,500 --> 14:10:47,500
multiple lands all linked into one big
19453
14:10:49,200 --> 14:10:50,200
win and these lands can be across town
19454
14:10:52,740 --> 14:10:53,740
from each other or even across the globe
19455
14:10:55,436 --> 14:10:56,436
now we've talked about some other terms
19456
14:10:57,596 --> 14:10:58,596
for instance can like a campus area
19457
14:11:00,000 --> 14:11:01,000
network or city area network and a man
19458
14:11:02,880 --> 14:11:03,880
or a metropolitan area network but all
19459
14:11:05,220 --> 14:11:06,220
of these could be in some way shape or
19460
14:11:07,320 --> 14:11:08,320
form are considered a Wan and of course
19461
14:11:10,020 --> 14:11:11,020
the biggest win that's out there is the
19462
14:11:13,140 --> 14:11:14,140
internet
19463
14:11:14,276 --> 14:11:15,276
usually referred to as the cloud because
19464
14:11:17,936 --> 14:11:18,936
on network diagrams a cloud is used to
19465
14:11:21,360 --> 14:11:22,360
represent it
19466
14:11:22,916 --> 14:11:23,916
now because of this Geographic distance
19467
14:11:26,160 --> 14:11:27,160
lands are generally slower than lands
19468
14:11:28,860 --> 14:11:29,860
because they have to as it makes sense
19469
14:11:31,140 --> 14:11:32,140
travel a longer distance to deliver data
19470
14:11:33,956 --> 14:11:34,956
just like if I sent a letter
19471
14:11:35,820 --> 14:11:36,820
internationally it's going to take
19472
14:11:37,436 --> 14:11:38,436
longer to get there than one across town
19473
14:11:39,596 --> 14:11:40,596
or even across the country that being
19474
14:11:41,756 --> 14:11:42,756
said newer Technologies such as fiber
19475
14:11:45,360 --> 14:11:46,360
optics and etc etc are making Wan
19476
14:11:48,720 --> 14:11:49,720
connections faster and therefore are
19477
14:11:50,936 --> 14:11:51,936
connecting parts of the globe that have
19478
14:11:52,860 --> 14:11:53,860
never really been connected before
19479
14:11:55,080 --> 14:11:56,080
so here's an example of what a wide area
19480
14:11:58,436 --> 14:11:59,436
network might look like let's say for
19481
14:12:00,540 --> 14:12:01,540
example that a company had two branches
19482
14:12:02,756 --> 14:12:03,756
one in New York
19483
14:12:04,680 --> 14:12:05,680
and the one in Houston each of the
19484
14:12:06,776 --> 14:12:07,776
branches has their own local area
19485
14:12:09,540 --> 14:12:10,540
network
19486
14:12:11,520 --> 14:12:12,520
here the one in New York and the one in
19487
14:12:14,520 --> 14:12:15,520
Houston obviously these are simplified
19488
14:12:16,560 --> 14:12:17,560
so imagine that instead of just two PCS
19489
14:12:19,256 --> 14:12:20,256
on each there are maybe five thousand
19490
14:12:21,300 --> 14:12:22,300
and instead of just one server maybe
19491
14:12:23,340 --> 14:12:24,340
there are 20. but they each have their
19492
14:12:26,580 --> 14:12:27,580
own switch to talk locally to one
19493
14:12:29,276 --> 14:12:30,276
another through Mac addresses
19494
14:12:32,276 --> 14:12:33,276
then there's a router on the edge of
19495
14:12:35,160 --> 14:12:36,160
each Network that connects it out to the
19496
14:12:37,800 --> 14:12:38,800
WAN or the internet
19497
14:12:39,956 --> 14:12:40,956
of course the WAN if configured
19498
14:12:43,800 --> 14:12:44,800
correctly can also connect these two
19499
14:12:47,276 --> 14:12:48,276
lands as though they seem like they're
19500
14:12:49,980 --> 14:12:50,980
in the same location just like their
19501
14:12:52,380 --> 14:12:53,380
next door now we could set up our own
19502
14:12:55,616 --> 14:12:56,616
Wan in other words we could have our own
19503
14:12:58,380 --> 14:12:59,380
cables and wires running through uh from
19504
14:13:02,400 --> 14:13:03,400
New York to Houston and that's going to
19505
14:13:04,380 --> 14:13:05,380
get really expensive and so we've come
19506
14:13:05,936 --> 14:13:06,936
up with Technologies to use the existing
19507
14:13:08,596 --> 14:13:09,596
Wan that's out there I.E the internet
19508
14:13:13,680 --> 14:13:14,680
in order to create secure connections
19509
14:13:16,200 --> 14:13:17,200
between two locations without having to
19510
14:13:19,200 --> 14:13:20,200
actually physically lay our own chords
19511
14:13:21,776 --> 14:13:22,776
however the idea is the same we connect
19512
14:13:24,840 --> 14:13:25,840
two lands through a Wan
19513
14:13:27,900 --> 14:13:28,900
and this allows users in both locations
19514
14:13:30,956 --> 14:13:31,956
to share data easily
19515
14:13:33,116 --> 14:13:34,116
a great example of how this is deployed
19516
14:13:35,040 --> 14:13:36,040
worldwide would be Banks or for instance
19517
14:13:37,980 --> 14:13:38,980
American Express or chase
19518
14:13:40,916 --> 14:13:41,916
you can buy something with your American
19519
14:13:42,956 --> 14:13:43,956
Express card just about anywhere in the
19520
14:13:45,300 --> 14:13:46,300
world and it still takes the money out
19521
14:13:48,596 --> 14:13:49,596
of your bank or puts it onto your
19522
14:13:50,580 --> 14:13:51,580
account almost instantaneously
19523
14:13:53,520 --> 14:13:54,520
now the process of establishing a wide
19524
14:13:56,276 --> 14:13:57,276
area network is really it can be quite
19525
14:13:59,700 --> 14:14:00,700
complicated although it's gotten more
19526
14:14:01,980 --> 14:14:02,980
and more simplified over the years so
19527
14:14:04,020 --> 14:14:05,020
I'm just going to go over some of the
19528
14:14:05,220 --> 14:14:06,220
basic steps and do it in a really
19529
14:14:06,596 --> 14:14:07,596
simplified manner uh basically what you
19530
14:14:09,300 --> 14:14:10,300
need to understand for Network plus a
19531
14:14:11,700 --> 14:14:12,700
good way to start with the Implement
19532
14:14:13,160 --> 14:14:14,160
implementation process to set up what we
19533
14:14:15,596 --> 14:14:16,596
call a VPN or a virtual
19534
14:14:20,040 --> 14:14:21,040
private
19535
14:14:22,680 --> 14:14:23,680
Network so the name implies it's not
19536
14:14:25,380 --> 14:14:26,380
actually a private Network that would be
19537
14:14:27,540 --> 14:14:28,540
one in which I actually have a cord
19538
14:14:29,276 --> 14:14:30,276
stretched across the country connecting
19539
14:14:31,616 --> 14:14:32,616
one computer to another rather this is a
19540
14:14:34,616 --> 14:14:35,616
virtual private Network
19541
14:14:36,300 --> 14:14:37,300
so this is a type of Wan and what it
19542
14:14:39,840 --> 14:14:40,840
does is it actually allows us
19543
14:14:44,040 --> 14:14:45,040
to use the public Wan the internet and
19544
14:14:48,060 --> 14:14:49,060
create a tunnel through it
19545
14:14:51,840 --> 14:14:52,840
called a virtual private Network that
19546
14:14:54,540 --> 14:14:55,540
then makes it seem like the two
19547
14:14:57,060 --> 14:14:58,060
locations are right there next to each
19548
14:14:59,340 --> 14:15:00,340
other the benefit of a VPN is that it
19549
14:15:01,680 --> 14:15:02,680
makes it secure
19550
14:15:03,240 --> 14:15:04,240
so once you basically install the
19551
14:15:06,660 --> 14:15:07,660
settings you need to put in some
19552
14:15:07,916 --> 14:15:08,916
administrative policies and rules so not
19553
14:15:10,436 --> 14:15:11,436
just anyone can tap into your tunnel
19554
14:15:12,720 --> 14:15:13,720
otherwise it wouldn't be very secure and
19555
14:15:14,756 --> 14:15:15,756
there wouldn't be any point we also need
19556
14:15:16,680 --> 14:15:17,680
to select certain users who are going to
19557
14:15:18,360 --> 14:15:19,360
be able to get access to it and how we
19558
14:15:20,456 --> 14:15:21,456
want to allow them to have these remote
19559
14:15:21,900 --> 14:15:22,900
capabilities we'll talk about a VPN in a
19560
14:15:24,416 --> 14:15:25,416
bit more detail and we've talked about
19561
14:15:25,680 --> 14:15:26,680
it a bit in the past
19562
14:15:27,360 --> 14:15:28,360
finally we have to add the user accounts
19563
14:15:30,660 --> 14:15:31,660
to our local networks
19564
14:15:33,116 --> 14:15:34,116
so that then they can communicate
19565
14:15:35,400 --> 14:15:36,400
throughout uh the Wan
19566
14:15:37,860 --> 14:15:38,860
this can be configured using either IP
19567
14:15:40,320 --> 14:15:41,320
addresses or Mac addresses or domain
19568
14:15:43,380 --> 14:15:44,380
names so just to go back over that again
19569
14:15:45,840 --> 14:15:46,840
I create the VPN I give access to the
19570
14:15:49,200 --> 14:15:50,200
users and then I connect those users to
19571
14:15:51,540 --> 14:15:52,540
the network perhaps I connect them to
19572
14:15:53,820 --> 14:15:54,820
the network from home perhaps from their
19573
14:15:56,456 --> 14:15:57,456
own internet access at home or their own
19574
14:15:59,220 --> 14:16:00,220
internet router but in some way I have
19575
14:16:01,380 --> 14:16:02,380
to give them access and that generally
19576
14:16:02,820 --> 14:16:03,820
involves some sort of special software
19577
14:16:04,740 --> 14:16:05,740
or device and some sort of
19578
14:16:07,560 --> 14:16:08,560
authentication such as a password or pin
19579
14:16:09,956 --> 14:16:10,956
number
19580
14:16:11,220 --> 14:16:12,220
now being the administrator for Awan can
19581
14:16:14,040 --> 14:16:15,040
actually be pretty demanding because
19582
14:16:15,116 --> 14:16:16,116
it's not restricted to a single location
19583
14:16:16,740 --> 14:16:17,740
the job involves a lot more than being a
19584
14:16:19,500 --> 14:16:20,500
land administrator because you might
19585
14:16:21,416 --> 14:16:22,416
have a land that's all in New York but
19586
14:16:23,456 --> 14:16:24,456
if I have a win I could have offices all
19587
14:16:25,256 --> 14:16:26,256
over the world so the main tasks though
19588
14:16:27,540 --> 14:16:28,540
are still the same they're just
19589
14:16:29,276 --> 14:16:30,276
generally on a much larger scale in fact
19590
14:16:31,800 --> 14:16:32,800
almost every task that both
19591
14:16:33,416 --> 14:16:34,416
administrators would share is just
19592
14:16:36,360 --> 14:16:37,360
larger in scale and just a little more
19593
14:16:38,400 --> 14:16:39,400
difficult for the wan to admin
19594
14:16:40,740 --> 14:16:41,740
so backups are just as important on a
19595
14:16:42,840 --> 14:16:43,840
Wan as they are in a land if not more so
19596
14:16:44,640 --> 14:16:45,640
because data loss of any kind is
19597
14:16:46,740 --> 14:16:47,740
something that needs to be avoided it's
19598
14:16:48,540 --> 14:16:49,540
the way an admin's job to be in charge
19599
14:16:50,520 --> 14:16:51,520
of backups for the entire wide area
19600
14:16:53,160 --> 14:16:54,160
network and make sure that everything
19601
14:16:54,240 --> 14:16:55,240
goes well the actual process of backing
19602
14:16:57,000 --> 14:16:58,000
up everything is virtually identical on
19603
14:16:59,340 --> 14:17:00,340
both networks however with Wan it's much
19604
14:17:01,740 --> 14:17:02,740
more difficult because as we said before
19605
14:17:04,220 --> 14:17:05,220
lands span over two or more physical
19606
14:17:07,500 --> 14:17:08,500
locations geographically and are
19607
14:17:10,200 --> 14:17:11,200
grouping Lan networks together so we
19608
14:17:13,860 --> 14:17:14,860
need to not only back up stuff at the
19609
14:17:15,596 --> 14:17:16,596
individual Land locations but then we
19610
14:17:17,160 --> 14:17:18,160
need to put all that together into one
19611
14:17:19,560 --> 14:17:20,560
big huge backup of course one of the
19612
14:17:22,616 --> 14:17:23,616
main differences we mentioned at the
19613
14:17:24,180 --> 14:17:25,180
outset is speed and so when we're trying
19614
14:17:27,480 --> 14:17:28,480
to back stuff up to a wan to the
19615
14:17:30,000 --> 14:17:31,000
internet
19616
14:17:30,900 --> 14:17:31,900
speed becomes an issue I can back
19617
14:17:32,580 --> 14:17:33,580
something up really quickly if I plug it
19618
14:17:34,500 --> 14:17:35,500
into the computer when I start going
19619
14:17:36,000 --> 14:17:37,000
over the network that's a little slower
19620
14:17:37,500 --> 14:17:38,500
and then when I start going over a Wan
19621
14:17:39,956 --> 14:17:40,956
it's going to get a little bit slower
19622
14:17:41,096 --> 14:17:42,096
too so full backups can take days
19623
14:17:43,800 --> 14:17:44,800
depending on the size of the WAN and
19624
14:17:45,840 --> 14:17:46,840
obviously the issue with that is if it
19625
14:17:47,400 --> 14:17:48,400
takes days for me to back something up
19626
14:17:48,956 --> 14:17:49,956
and I'm working on it then by the time
19627
14:17:50,820 --> 14:17:51,820
it's backed up it's actually hasn't
19628
14:17:52,800 --> 14:17:53,800
gotten the backup at all and so we have
19629
14:17:54,720 --> 14:17:55,720
to deal with all sorts of stuff when
19630
14:17:56,220 --> 14:17:57,220
we're doing this
19631
14:17:57,480 --> 14:17:58,480
so as you can see here I generally might
19632
14:18:00,416 --> 14:18:01,416
have some sort of off-site
19633
14:18:03,360 --> 14:18:04,360
backup area that all the data would sort
19634
14:18:06,360 --> 14:18:07,360
of Route into sometimes what we'll do is
19635
14:18:09,480 --> 14:18:10,480
we'll actually back stuff onto a local
19636
14:18:12,240 --> 14:18:13,240
backup
19637
14:18:13,380 --> 14:18:14,380
and then the local backup will be backed
19638
14:18:15,660 --> 14:18:16,660
up to a cloud backup or a Wan backup
19639
14:18:18,720 --> 14:18:19,720
so we have to deal with space issues and
19640
14:18:22,500 --> 14:18:23,500
we also have to deal with speed issues
19641
14:18:26,276 --> 14:18:27,276
now when it comes to backups as you can
19642
14:18:28,320 --> 14:18:29,320
imagine that's some pretty important
19643
14:18:29,820 --> 14:18:30,820
data that's flying over the network and
19644
14:18:32,220 --> 14:18:33,220
so I also need to make sure not only my
19645
14:18:34,140 --> 14:18:35,140
backups but my entire network are secure
19646
14:18:36,480 --> 14:18:37,480
and this is a massive job for the
19647
14:18:38,340 --> 14:18:39,340
administrator of Rowan in fact generally
19648
14:18:40,616 --> 14:18:41,616
when administrators don't do this they
19649
14:18:42,660 --> 14:18:43,660
hire someone else to specifically focus
19650
14:18:44,700 --> 14:18:45,700
on security again the big difference
19651
14:18:47,096 --> 14:18:48,096
with Wan is that the network is not
19652
14:18:49,436 --> 14:18:50,436
limited to a single location so there
19653
14:18:51,480 --> 14:18:52,480
are many more points for Access for
19654
14:18:53,456 --> 14:18:54,456
people who might have nefarious uh
19655
14:18:55,916 --> 14:18:56,916
purposes to get into our Network
19656
14:18:58,680 --> 14:18:59,680
this means the administrators not only
19657
14:19:00,660 --> 14:19:01,660
controlling the security at each
19658
14:19:02,756 --> 14:19:03,756
physical location but also the security
19659
14:19:05,096 --> 14:19:06,096
of the entire network as a whole
19660
14:19:08,060 --> 14:19:09,060
theoretically if an attacker were to
19661
14:19:10,740 --> 14:19:11,740
infiltrate one of the lands it could
19662
14:19:12,360 --> 14:19:13,360
infect the rest of the WAN so we have to
19663
14:19:14,936 --> 14:19:15,936
have a lot of fault sort of safety
19664
14:19:16,800 --> 14:19:17,800
measures in there as well it makes our
19665
14:19:19,140 --> 14:19:20,140
job really difficult and we not only
19666
14:19:21,596 --> 14:19:22,596
have to spread against these attacks but
19667
14:19:24,180 --> 14:19:25,180
also the spread of attacks if one site
19668
14:19:27,900 --> 14:19:28,900
gets infiltrated well I can't do
19669
14:19:30,240 --> 14:19:31,240
anything about that at that point but I
19670
14:19:31,740 --> 14:19:32,740
want to make sure all my other sites
19671
14:19:32,820 --> 14:19:33,820
don't get infiltrated as well
19672
14:19:34,860 --> 14:19:35,860
so here we see the same wind from
19673
14:19:37,020 --> 14:19:38,020
earlier but unfortunately a virus has
19674
14:19:40,380 --> 14:19:41,380
been sent by a hacker and it's making
19675
14:19:42,180 --> 14:19:43,180
its way through the wan to the other
19676
14:19:44,700 --> 14:19:45,700
land this is an example of something an
19677
14:19:49,140 --> 14:19:50,140
admin would have to be diligent about in
19678
14:19:52,200 --> 14:19:53,200
some ways what we want to do is create
19679
14:19:53,880 --> 14:19:54,880
some sort of wall here so that way the
19680
14:19:57,300 --> 14:19:58,300
virus or the logic bomb in this case
19681
14:19:59,456 --> 14:20:00,456
couldn't make its way over and just got
19682
14:20:02,040 --> 14:20:03,040
stuck and stayed in Houston while it's
19683
14:20:04,200 --> 14:20:05,200
still a pretty bad scenario at least New
19684
14:20:06,660 --> 14:20:07,660
York hasn't gotten infected
19685
14:20:09,240 --> 14:20:10,240
so in this module I really briefly
19686
14:20:11,756 --> 14:20:12,756
talked about a Wan or a wide area
19687
14:20:14,700 --> 14:20:15,700
network
19688
14:20:15,956 --> 14:20:16,956
remember a Wan is comprised of several
19689
14:20:19,860 --> 14:20:20,860
lands that are connected
19690
14:20:22,380 --> 14:20:23,380
over a geographic area
19691
14:20:24,596 --> 14:20:25,596
in some cases we're going to connect
19692
14:20:27,360 --> 14:20:28,360
them through the use of what's called a
19693
14:20:30,900 --> 14:20:31,900
VPN
19694
14:20:31,980 --> 14:20:32,980
well we have a VPN or a virtual private
19695
14:20:35,220 --> 14:20:36,220
Network it creates a tunnel over the
19696
14:20:38,456 --> 14:20:39,456
Internet which is our public switched
19697
14:20:40,740 --> 14:20:41,740
Network or our public network and we
19698
14:20:43,916 --> 14:20:44,916
create a private Network within that
19699
14:20:45,660 --> 14:20:46,660
using all sorts of protocols we'll
19700
14:20:47,220 --> 14:20:48,220
discuss so that way these two lands can
19701
14:20:49,740 --> 14:20:50,740
communicate as though they are actually
19702
14:20:51,660 --> 14:20:52,660
one Lan or they're right next to each
19703
14:20:53,880 --> 14:20:54,880
other we also need to have user accounts
19704
14:20:56,520 --> 14:20:57,520
so that way the users
19705
14:20:59,880 --> 14:21:00,880
can't just not anyone can get onto a
19706
14:21:02,276 --> 14:21:03,276
network they have to have a specific
19707
14:21:03,596 --> 14:21:04,596
password authentication Etc and those
19708
14:21:06,000 --> 14:21:07,000
users also have to have access somehow
19709
14:21:09,300 --> 14:21:10,300
whether that's through the internet or
19710
14:21:11,880 --> 14:21:12,880
they actually are physically connected
19711
14:21:13,436 --> 14:21:14,436
through our land site
19712
14:21:15,180 --> 14:21:16,180
we also talked about some of the
19713
14:21:16,436 --> 14:21:17,436
administrative tasks that can be
19714
14:21:17,756 --> 14:21:18,756
difficult for lands specifically backup
19715
14:21:20,400 --> 14:21:21,400
where we're dealing not only with speed
19716
14:21:23,040 --> 14:21:24,040
but also with amount of data
19717
14:21:26,820 --> 14:21:27,820
and we talked about security we're not
19718
14:21:29,820 --> 14:21:30,820
just stopping intrusions
19719
14:21:32,880 --> 14:21:33,880
but we also need to limit the spread of
19720
14:21:37,020 --> 14:21:38,020
an attack
19721
14:21:42,030 --> 14:21:43,030
[Music]
19722
14:22:02,116 --> 14:22:03,116
wide area networks Wan transmission
19723
14:22:05,400 --> 14:22:06,400
technologies
19724
14:22:07,256 --> 14:22:08,256
so in the last module we talked very uh
19725
14:22:11,580 --> 14:22:12,580
briefly and in an overview sense about
19726
14:22:14,880 --> 14:22:15,880
the implementation and administration of
19727
14:22:17,340 --> 14:22:18,340
wide area networks now the reason we
19728
14:22:19,320 --> 14:22:20,320
didn't get into too much detail is
19729
14:22:21,060 --> 14:22:22,060
because it gets quite complicated when
19730
14:22:24,000 --> 14:22:25,000
we talk not only about connecting
19731
14:22:25,740 --> 14:22:26,740
computers together in a local area
19732
14:22:27,240 --> 14:22:28,240
network but in a wide area network and
19733
14:22:29,936 --> 14:22:30,936
as a result the Technologies become more
19734
14:22:32,700 --> 14:22:33,700
and more complex and just like we have
19735
14:22:35,276 --> 14:22:36,276
people who specialize in lands they're
19736
14:22:36,720 --> 14:22:37,720
people who specialize in lands since the
19737
14:22:39,000 --> 14:22:40,000
purpose of network plus is to give you
19738
14:22:40,500 --> 14:22:41,500
an overview of all the stuff we just
19739
14:22:42,360 --> 14:22:43,360
want to get you familiar with certain
19740
14:22:43,860 --> 14:22:44,860
terms so in case you were to come across
19741
14:22:46,436 --> 14:22:47,436
them you would sort of know where to
19742
14:22:48,776 --> 14:22:49,776
look or what to start with when you look
19743
14:22:51,116 --> 14:22:52,116
for more information now in this module
19744
14:22:53,520 --> 14:22:54,520
we're going to talk a little more
19745
14:22:54,416 --> 14:22:55,416
specifically about Wan transmission
19746
14:22:56,520 --> 14:22:57,520
techniques again we're going to look at
19747
14:22:58,800 --> 14:22:59,800
this from a mile high view so the
19748
14:23:01,380 --> 14:23:02,380
techniques then the transmission
19749
14:23:02,756 --> 14:23:03,756
technologies we're going to talk about
19750
14:23:04,500 --> 14:23:05,500
are specifically ISDN which you might
19751
14:23:07,200 --> 14:23:08,200
remember if you've been around for a
19752
14:23:08,820 --> 14:23:09,820
while it's mostly been supplanted by DSL
19753
14:23:11,820 --> 14:23:12,820
and cable to this uh nowadays as
19754
14:23:15,720 --> 14:23:16,720
actually you have most of these
19755
14:23:17,580 --> 14:23:18,580
Technologies but some of these are still
19756
14:23:19,200 --> 14:23:20,200
around and you probably have heard of
19757
14:23:20,340 --> 14:23:21,340
them so ISDN is the first we're going to
19758
14:23:22,080 --> 14:23:23,080
talk about we're also going to talk
19759
14:23:23,580 --> 14:23:24,580
about t carrier and if you've ever seen
19760
14:23:25,436 --> 14:23:26,436
the term a T1 or T3 line that's what
19761
14:23:28,740 --> 14:23:29,740
this is referring to we're going to talk
19762
14:23:30,596 --> 14:23:31,596
about Sonet which is responsible for a
19763
14:23:33,840 --> 14:23:34,840
different type of classification it's
19764
14:23:36,300 --> 14:23:37,300
also using some Optics which is why it's
19765
14:23:38,700 --> 14:23:39,700
a bit faster and required a completely
19766
14:23:40,980 --> 14:23:41,980
different form of rating the cabling and
19767
14:23:44,756 --> 14:23:45,756
the speeds and then we're going to look
19768
14:23:46,560 --> 14:23:47,560
at some technologies that allow the data
19769
14:23:48,776 --> 14:23:49,776
to transmit over this stuff these T
19770
14:23:52,800 --> 14:23:53,800
carrier and sonets including x25 and
19771
14:23:55,800 --> 14:23:56,800
frame relay x25 was supplanted by frame
19772
14:23:59,220 --> 14:24:00,220
relay and ATM which is not the thing you
19773
14:24:02,040 --> 14:24:03,040
put your card into to get money out of
19774
14:24:04,320 --> 14:24:05,320
but rather a technology of protocol that
19775
14:24:06,840 --> 14:24:07,840
allows us to communicate over when
19776
14:24:08,936 --> 14:24:09,936
Networks
19777
14:24:10,320 --> 14:24:11,320
so the first one we're going to talk
19778
14:24:11,456 --> 14:24:12,456
about here is the integrated Services
19779
14:24:13,740 --> 14:24:14,740
digital Network or
19780
14:24:16,700 --> 14:24:17,700
ISDN now uh the ISDN is very high speed
19781
14:24:21,480 --> 14:24:22,480
but it's also high cost and the reason
19782
14:24:24,416 --> 14:24:25,416
for that is because in order to use ISDN
19783
14:24:26,880 --> 14:24:27,880
a special phone line is required to set
19784
14:24:29,040 --> 14:24:30,040
it up now the line is paid for monthly
19785
14:24:31,740 --> 14:24:32,740
just like with any phone line and this
19786
14:24:34,200 --> 14:24:35,200
is where the high costs come in because
19787
14:24:36,180 --> 14:24:37,180
the service is pretty expensive to pay
19788
14:24:38,040 --> 14:24:39,040
for every month in order to set up a
19789
14:24:40,616 --> 14:24:41,616
connection the phone line has to dial
19790
14:24:43,140 --> 14:24:44,140
the address of the receiving computer
19791
14:24:44,520 --> 14:24:45,520
very similar to the process of calling a
19792
14:24:47,340 --> 14:24:48,340
phone on the other end and once the
19793
14:24:49,256 --> 14:24:50,256
connection is established you can drop
19794
14:24:50,640 --> 14:24:51,640
it by just hanging it up so if we were
19795
14:24:53,820 --> 14:24:54,820
to consider this for instance to be our
19796
14:24:57,416 --> 14:24:58,416
um uh ISDN line you would notice there
19797
14:25:00,720 --> 14:25:01,720
is sort of a box here and that's because
19798
14:25:02,820 --> 14:25:03,820
we need a special box to allow the istn
19799
14:25:05,040 --> 14:25:06,040
to communicate and it would then
19800
14:25:06,480 --> 14:25:07,480
communicate onto the other side to the
19801
14:25:08,756 --> 14:25:09,756
ISP now what's interesting here is this
19802
14:25:11,040 --> 14:25:12,040
is actually a plain old telephone system
19803
14:25:13,256 --> 14:25:14,256
line or uh by the way Plano telephone
19804
14:25:16,800 --> 14:25:17,800
system or pstn public switch telephone
19805
14:25:19,500 --> 14:25:20,500
Network so this is using uh old
19806
14:25:22,980 --> 14:25:23,980
telephone technology but the difference
19807
14:25:25,436 --> 14:25:26,436
is instead of using the one that's
19808
14:25:27,116 --> 14:25:28,116
already been installed into your home or
19809
14:25:29,640 --> 14:25:30,640
to your office it's actually another one
19810
14:25:31,436 --> 14:25:32,436
that has to be laid down which is how
19811
14:25:33,060 --> 14:25:34,060
it's different from DSL now there are
19812
14:25:35,220 --> 14:25:36,220
actually two different types of ISDN
19813
14:25:37,256 --> 14:25:38,256
we've talked about these in a plus as
19814
14:25:39,540 --> 14:25:40,540
well one is the Bri and the other is PRI
19815
14:25:43,700 --> 14:25:44,700
Bri by the way stands for basic
19816
14:25:48,660 --> 14:25:49,660
rate interface and this one stands for
19817
14:25:52,020 --> 14:25:53,020
primary rate interface primary is a bit
19818
14:25:55,980 --> 14:25:56,980
faster
19819
14:25:57,416 --> 14:25:58,416
but it's also a little bit more
19820
14:25:58,800 --> 14:25:59,800
expensive now there are certain speeds
19821
14:26:01,436 --> 14:26:02,436
these operate at generally 64 kilobits
19822
14:26:04,020 --> 14:26:05,020
per second or 128 kilobits per second
19823
14:26:06,840 --> 14:26:07,840
again that's pretty slow when we compare
19824
14:26:09,956 --> 14:26:10,956
it to modern day DSL or modern day cable
19825
14:26:12,840 --> 14:26:13,840
Technologies but this was a dedicated
19826
14:26:14,700 --> 14:26:15,700
line specifically from you to uh the ISP
19827
14:26:18,840 --> 14:26:19,840
which is the reason why even though it
19828
14:26:21,060 --> 14:26:22,060
was a little less fast it was still used
19829
14:26:22,800 --> 14:26:23,800
although nowadays we don't see it used
19830
14:26:25,140 --> 14:26:26,140
as much because it requires special
19831
14:26:27,000 --> 14:26:28,000
technology special boxes special
19832
14:26:29,040 --> 14:26:30,040
equipment and so on and so forth
19833
14:26:31,500 --> 14:26:32,500
now the next technology I want to talk
19834
14:26:33,300 --> 14:26:34,300
about are called t carrier lines T
19835
14:26:35,640 --> 14:26:36,640
carrier lines are dedicated digital
19836
14:26:37,436 --> 14:26:38,436
lines that are leased from the telephone
19837
14:26:39,480 --> 14:26:40,480
companies much like ISDN but they're
19838
14:26:42,360 --> 14:26:43,360
high speed and they establish a stable
19839
14:26:44,400 --> 14:26:45,400
connection on both sides just like ISDN
19840
14:26:46,916 --> 14:26:47,916
now these connections are always open
19841
14:26:49,200 --> 14:26:50,200
unlike isdns so communication can be
19842
14:26:51,956 --> 14:26:52,956
made between the two ends whenever it's
19843
14:26:53,880 --> 14:26:54,880
needed there's no hanging up in other
19844
14:26:55,860 --> 14:26:56,860
words because they provide such a good
19845
14:26:58,380 --> 14:26:59,380
dedicated link they're also expensive to
19846
14:27:01,616 --> 14:27:02,616
use on lands although they were faster
19847
14:27:04,320 --> 14:27:05,320
and so we saw a lot of companies used to
19848
14:27:06,660 --> 14:27:07,660
have T1 or T3 connections and they might
19849
14:27:09,116 --> 14:27:10,116
still do now there are different types
19850
14:27:11,880 --> 14:27:12,880
of T connections available depending on
19851
14:27:14,096 --> 14:27:15,096
the speed you require the first T1 is
19852
14:27:17,580 --> 14:27:18,580
the slowest of the four types now
19853
14:27:21,240 --> 14:27:22,240
like the other three it does create
19854
14:27:24,240 --> 14:27:25,240
dedicated ends and it's secure
19855
14:27:28,380 --> 14:27:29,380
and t1s are generally going to be used
19856
14:27:30,180 --> 14:27:31,180
to connect lands together so for
19857
14:27:34,080 --> 14:27:35,080
instance if I have my Lan on in one side
19858
14:27:37,436 --> 14:27:38,436
of the city and you have another one we
19859
14:27:38,756 --> 14:27:39,756
might get or lease a line from the
19860
14:27:40,680 --> 14:27:41,680
telephone company to directly connect
19861
14:27:42,000 --> 14:27:43,000
them if we don't want to use the
19862
14:27:43,740 --> 14:27:44,740
internet nowadays we have the internet
19863
14:27:45,300 --> 14:27:46,300
so a lot of organizations are going to
19864
14:27:47,040 --> 14:27:48,040
use that and just get a very fast
19865
14:27:48,300 --> 14:27:49,300
connection perhaps a T1 or T3 line
19866
14:27:50,640 --> 14:27:51,640
between them and their ISP your internet
19867
14:27:53,640 --> 14:27:54,640
service provider you might sometimes see
19868
14:27:55,860 --> 14:27:56,860
this by the way referred to as Digital
19869
14:27:58,200 --> 14:27:59,200
Signal one or DS1
19870
14:28:03,060 --> 14:28:04,060
so if you ever see DS it's the same
19871
14:28:05,096 --> 14:28:06,096
thing as a t line now T2 as you can
19872
14:28:07,800 --> 14:28:08,800
imagine are slightly faster than T1
19873
14:28:09,840 --> 14:28:10,840
lines they're not much different they're
19874
14:28:11,756 --> 14:28:12,756
for some reason used a little less it's
19875
14:28:14,220 --> 14:28:15,220
probably because the speed is not worth
19876
14:28:16,020 --> 14:28:17,020
the uh upgrade uh and because
19877
14:28:20,400 --> 14:28:21,400
the T3 is actually even faster than T1
19878
14:28:23,220 --> 14:28:24,220
and 2 T2 put together so if we add both
19879
14:28:26,640 --> 14:28:27,640
of those together we'll get a T3 this is
19880
14:28:28,860 --> 14:28:29,860
sometimes also called a DS3 and t1s
19881
14:28:34,436 --> 14:28:35,436
and t3s
19882
14:28:36,540 --> 14:28:37,540
are the most commonly one used T lines
19883
14:28:39,840 --> 14:28:40,840
that you'll probably see out in the
19884
14:28:41,160 --> 14:28:42,160
field
19885
14:28:42,000 --> 14:28:43,000
T4 is even faster in fact it is a
19886
14:28:45,660 --> 14:28:46,660
combination of all of the top ones
19887
14:28:48,540 --> 14:28:49,540
meaning it's faster than all of them
19888
14:28:50,580 --> 14:28:51,580
combined but it's also pretty expensive
19889
14:28:52,800 --> 14:28:53,800
and for most part we're going to see if
19890
14:28:54,540 --> 14:28:55,540
you really want to fast line a T3 and if
19891
14:28:57,360 --> 14:28:58,360
not you'll probably see a T1 out in the
19892
14:28:59,400 --> 14:29:00,400
field a lot of companies maybe 10 15
19893
14:29:01,380 --> 14:29:02,380
years ago used to connect via a T1 or a
19894
14:29:04,436 --> 14:29:05,436
T3
19895
14:29:05,416 --> 14:29:06,416
sometimes you'll still see that if it's
19896
14:29:07,500 --> 14:29:08,500
a very large company otherwise they're
19897
14:29:09,060 --> 14:29:10,060
going to connect via perhaps a DSL or
19898
14:29:11,820 --> 14:29:12,820
cable connection generally commercially
19899
14:29:13,980 --> 14:29:14,980
again this was before you had cable and
19900
14:29:17,880 --> 14:29:18,880
DSL at everyone's homes so now the
19901
14:29:20,220 --> 14:29:21,220
technology has shifted a bit but it's
19902
14:29:21,776 --> 14:29:22,776
important to know about this for Network
19903
14:29:23,040 --> 14:29:24,040
plus because they're testing knowledge
19904
14:29:24,840 --> 14:29:25,840
that you might see even Legacy
19905
14:29:26,400 --> 14:29:27,400
information meaning old information that
19906
14:29:28,860 --> 14:29:29,860
you might run into or encounter at an
19907
14:29:31,080 --> 14:29:32,080
office or a building
19908
14:29:32,640 --> 14:29:33,640
now in 1984 if you recall your history
19909
14:29:36,720 --> 14:29:37,720
or if you were around then you might
19910
14:29:38,640 --> 14:29:39,640
recall that 18t in the United States
19911
14:29:40,140 --> 14:29:41,140
held a monopoly on the network carrier
19912
14:29:42,480 --> 14:29:43,480
industry I.E phones so preceding this
19913
14:29:45,300 --> 14:29:46,300
smaller companies were given a chance
19914
14:29:47,580 --> 14:29:48,580
and a challenge to come up with a system
19915
14:29:49,500 --> 14:29:50,500
that was going to rival a t that the one
19916
14:29:52,680 --> 14:29:53,680
that they had so a company called Bell
19917
14:29:55,080 --> 14:29:56,080
Communications which you might have
19918
14:29:56,700 --> 14:29:57,700
heard of came up with this called the
19919
14:29:59,456 --> 14:30:00,456
synchronous Optical Network or Sonet now
19920
14:30:02,936 --> 14:30:03,936
sonnet is fiber optic okay so rather
19921
14:30:06,300 --> 14:30:07,300
than being copper we're dealing with
19922
14:30:08,040 --> 14:30:09,040
fiber optics which uses plastic or glass
19923
14:30:10,436 --> 14:30:11,436
and delivers information and either
19924
14:30:13,860 --> 14:30:14,860
voice data and Video in much higher
19925
14:30:16,436 --> 14:30:17,436
speeds as a result because it's using
19926
14:30:19,020 --> 14:30:20,020
light pulses
19927
14:30:20,456 --> 14:30:21,456
now this achievement was so great that
19928
14:30:23,276 --> 14:30:24,276
it sparked a new system of defining data
19929
14:30:25,380 --> 14:30:26,380
rates meaning that the old systems uh
19930
14:30:29,276 --> 14:30:30,276
just didn't
19931
14:30:31,020 --> 14:30:32,020
it was so slow in comparison there was
19932
14:30:33,360 --> 14:30:34,360
nothing that could sort of uh uh counter
19933
14:30:36,956 --> 14:30:37,956
this and so we start seeing the OC
19934
14:30:39,000 --> 14:30:40,000
levels like for instance one you might
19935
14:30:41,040 --> 14:30:42,040
have seen is
19936
14:30:42,320 --> 14:30:43,320
oc9 and that would be really really fast
19937
14:30:45,300 --> 14:30:46,300
now don't worry about knowing the
19938
14:30:47,040 --> 14:30:48,040
specific speeds for the network plus
19939
14:30:48,540 --> 14:30:49,540
exam that's why I'm not covering them
19940
14:30:50,040 --> 14:30:51,040
what you just want to make sure of is if
19941
14:30:52,080 --> 14:30:53,080
you see OC versus like a T1 or T3 you
19942
14:30:54,956 --> 14:30:55,956
want to know that the OC is generally
19943
14:30:56,340 --> 14:30:57,340
going to be faster because again look at
19944
14:30:58,320 --> 14:30:59,320
this word Optical carrier levels
19945
14:31:01,200 --> 14:31:02,200
now in the mid
19946
14:31:03,240 --> 14:31:04,240
um 1970s we had something called x25
19947
14:31:06,540 --> 14:31:07,540
which was everywhere and this was
19948
14:31:09,840 --> 14:31:10,840
technology that was developed as a way
19949
14:31:11,520 --> 14:31:12,520
to send data over copper wiring so not
19950
14:31:14,220 --> 14:31:15,220
that OC stuff but more the t1s ETC and
19951
14:31:17,096 --> 14:31:18,096
isdns but during its creation everyone
19952
14:31:19,740 --> 14:31:20,740
in the networking Communications world
19953
14:31:21,180 --> 14:31:22,180
had a part in creating and implementing
19954
14:31:23,040 --> 14:31:24,040
it you might see x25 or terms and you
19955
14:31:26,400 --> 14:31:27,400
used to talk about how they would take
19956
14:31:29,400 --> 14:31:30,400
data and send it over these uh this
19957
14:31:33,116 --> 14:31:34,116
technologies that it had and its format
19958
14:31:36,000 --> 14:31:37,000
was virtually Universal however it was
19959
14:31:38,700 --> 14:31:39,700
really limited by speeds because of the
19960
14:31:40,980 --> 14:31:41,980
copper wiring and just because of the
19961
14:31:42,360 --> 14:31:43,360
way that the protocol worked uh which
19962
14:31:45,060 --> 14:31:46,060
I'll write up here
19963
14:31:48,116 --> 14:31:49,116
and so it was replaced by something
19964
14:31:50,540 --> 14:31:51,540
called frame relay now frame relay is a
19965
14:31:54,776 --> 14:31:55,776
protocol that was developed basically to
19966
14:31:57,000 --> 14:31:58,000
transfer between LAN
19967
14:32:00,360 --> 14:32:01,360
and Wan end points in other words
19968
14:32:02,756 --> 14:32:03,756
between My Lan and the ISP or my larger
19969
14:32:06,416 --> 14:32:07,416
wide area network the way it functions
19970
14:32:08,820 --> 14:32:09,820
is not important just know that it
19971
14:32:10,500 --> 14:32:11,500
functions similarly to x25 but it's
19972
14:32:14,340 --> 14:32:15,340
faster
19973
14:32:18,416 --> 14:32:19,416
and it has a more modern build behind it
19974
14:32:21,060 --> 14:32:22,060
they're also both called packet
19975
14:32:23,640 --> 14:32:24,640
switching Technologies and we'll talk
19976
14:32:25,980 --> 14:32:26,980
about that later but frame relay can can
19977
14:32:29,756 --> 14:32:30,756
send smaller packets and it can send
19978
14:32:32,756 --> 14:32:33,756
them faster
19979
14:32:37,740 --> 14:32:38,740
we'll talk more about uh packet
19980
14:32:39,720 --> 14:32:40,720
switching in the next module
19981
14:32:43,500 --> 14:32:44,500
finally I want to talk about
19982
14:32:44,720 --> 14:32:45,720
asynchronous transfer mode or ATMs if
19983
14:32:48,840 --> 14:32:49,840
you ever see ATM on the test this is
19984
14:32:50,400 --> 14:32:51,400
what they're referring to a wide area
19985
14:32:52,380 --> 14:32:53,380
network uh transmission or transfer mode
19986
14:32:55,320 --> 14:32:56,320
it was introduced in the 90s as a
19987
14:32:57,416 --> 14:32:58,416
successor two frame relay and it was
19988
14:32:59,936 --> 14:33:00,936
really considered a breakthrough because
19989
14:33:01,580 --> 14:33:02,580
it was what they call an end-to-end
19990
14:33:04,860 --> 14:33:05,860
solution that could work either desk
19991
14:33:07,500 --> 14:33:08,500
from the desktop or remotely what this
19992
14:33:10,140 --> 14:33:11,140
meant is that it could work on a Wan a
19993
14:33:13,380 --> 14:33:14,380
wide area network and within the land
19994
14:33:15,616 --> 14:33:16,616
however this sort of proves not really
19995
14:33:18,060 --> 14:33:19,060
to be true because the technology sort
19996
14:33:20,756 --> 14:33:21,756
of got
19997
14:33:21,900 --> 14:33:22,900
for lack of a better word pushed out of
19998
14:33:24,720 --> 14:33:25,720
the land market because other
19999
14:33:26,160 --> 14:33:27,160
technologists came around that were just
20000
14:33:27,660 --> 14:33:28,660
better it was actually pretty expensive
20001
14:33:30,416 --> 14:33:31,416
to use but it did have some benefits one
20002
14:33:32,936 --> 14:33:33,936
of the main ones just like with the T
20003
14:33:34,800 --> 14:33:35,800
aligns is it could transfer data voice
20004
14:33:37,680 --> 14:33:38,680
and video it's also a packet switching
20005
14:33:40,616 --> 14:33:41,616
technology something we're going to talk
20006
14:33:41,820 --> 14:33:42,820
about and it's pretty fast and one of
20007
14:33:44,096 --> 14:33:45,096
the major things we're going to talk
20008
14:33:45,240 --> 14:33:46,240
about with it is that it used what are
20009
14:33:46,980 --> 14:33:47,980
called cells and the cells were 53 bytes
20010
14:33:50,820 --> 14:33:51,820
long which is fairly large for a packet
20011
14:33:53,160 --> 14:33:54,160
of data and I shouldn't say even pack it
20012
14:33:55,680 --> 14:33:56,680
because what it really we're talking
20013
14:33:57,180 --> 14:33:58,180
about is it was replaced by cells so
20014
14:33:59,936 --> 14:34:00,936
these cells have proven to work more
20015
14:34:02,756 --> 14:34:03,756
efficiently for transferring than
20016
14:34:04,800 --> 14:34:05,800
packets that were used by frame relay
20017
14:34:07,020 --> 14:34:08,020
and this is really sort of the legacy of
20018
14:34:09,060 --> 14:34:10,060
ATM was using these cells that had a lot
20019
14:34:11,640 --> 14:34:12,640
more information in them than the frame
20020
14:34:13,680 --> 14:34:14,680
relay packets which were much smaller
20021
14:34:15,360 --> 14:34:16,360
obviously the more information we could
20022
14:34:16,800 --> 14:34:17,800
cram into a packet the faster we could
20023
14:34:18,360 --> 14:34:19,360
send it the quicker we can get
20024
14:34:19,740 --> 14:34:20,740
information to the other side
20025
14:34:21,840 --> 14:34:22,840
of a network or a wide area network
20026
14:34:24,956 --> 14:34:25,956
and if we just look at this this is just
20027
14:34:27,000 --> 14:34:28,000
to show us that it has again voice
20028
14:34:30,480 --> 14:34:31,480
data and video
20029
14:34:33,000 --> 14:34:34,000
all in one
20030
14:34:35,220 --> 14:34:36,220
cell which was sort of the amazing thing
20031
14:34:38,880 --> 14:34:39,880
that this technology ATM did good way to
20032
14:34:41,880 --> 14:34:42,880
remember it is to think about going to
20033
14:34:43,256 --> 14:34:44,256
the ATM you can check your balance you
20034
14:34:44,936 --> 14:34:45,936
can get money you can pull out of your
20035
14:34:46,140 --> 14:34:47,140
savings you can pull out of your
20036
14:34:47,160 --> 14:34:48,160
checking and so it sort of does a lot of
20037
14:34:49,020 --> 14:34:50,020
things when it comes to your bank same
20038
14:34:50,700 --> 14:34:51,700
with the ATM cell
20039
14:34:52,980 --> 14:34:53,980
all right so those are all the WAN
20040
14:34:55,500 --> 14:34:56,500
transmission technologies I just want to
20041
14:34:56,936 --> 14:34:57,936
briefly go over obviously we took a very
20042
14:34:59,040 --> 14:35:00,040
cursory overview of them and and you
20043
14:35:00,956 --> 14:35:01,956
could probably Google and find a lot
20044
14:35:02,456 --> 14:35:03,456
more information that's going to go over
20045
14:35:03,660 --> 14:35:04,660
your head and you don't need to know
20046
14:35:04,980 --> 14:35:05,980
that for Network plus but what I want
20047
14:35:06,360 --> 14:35:07,360
you to remember again is that ISDN was
20048
14:35:08,936 --> 14:35:09,936
used it really either came in that BPI
20049
14:35:12,776 --> 14:35:13,776
or rather Bri or PRI modes PR was
20050
14:35:16,860 --> 14:35:17,860
slightly faster it was either in 64
20051
14:35:19,200 --> 14:35:20,200
kilobits per second or 128 kilobits per
20052
14:35:21,540 --> 14:35:22,540
second it worked over the existing pots
20053
14:35:24,180 --> 14:35:25,180
or pstn phone system but it was still
20054
14:35:28,020 --> 14:35:29,020
relatively slow we don't see it much
20055
14:35:29,640 --> 14:35:30,640
anymore although it was pretty big maybe
20056
14:35:31,320 --> 14:35:32,320
15 years ago the T carriers the big ones
20057
14:35:34,020 --> 14:35:35,020
you're going to see are T1 and T3
20058
14:35:36,180 --> 14:35:37,180
remember that T3 is faster than T1 Sonet
20059
14:35:40,860 --> 14:35:41,860
as well was introduced
20060
14:35:43,500 --> 14:35:44,500
excuse me it replaced
20061
14:35:46,436 --> 14:35:47,436
the sort of tea way of looking at speeds
20062
14:35:49,860 --> 14:35:50,860
with the OC
20063
14:35:51,540 --> 14:35:52,540
system OC
20064
14:35:54,660 --> 14:35:55,660
is fiber optic and if you think about
20065
14:35:56,756 --> 14:35:57,756
the O in there being optic that's why it
20066
14:35:59,640 --> 14:36:00,640
was faster x25 and frame relay both ways
20067
14:36:03,900 --> 14:36:04,900
of transferring
20068
14:36:05,520 --> 14:36:06,520
when data this was replaced mostly by
20069
14:36:09,240 --> 14:36:10,240
ATM both of these are what we call
20070
14:36:11,340 --> 14:36:12,340
packet switching which we will look at
20071
14:36:14,520 --> 14:36:15,520
in the next module
20072
14:36:16,860 --> 14:36:17,860
and the important thing with ATM again
20073
14:36:19,040 --> 14:36:20,040
not the thing that you put your money
20074
14:36:21,300 --> 14:36:22,300
into but rather a Wan technology it was
20075
14:36:24,360 --> 14:36:25,360
marketed as being
20076
14:36:26,400 --> 14:36:27,400
end to end meaning it could work from
20077
14:36:29,096 --> 14:36:30,096
the computer to the computer although
20078
14:36:31,080 --> 14:36:32,080
nowadays we really use it in Wan
20079
14:36:33,060 --> 14:36:34,060
Technologies from a land to a land
20080
14:36:35,276 --> 14:36:36,276
endpoint and the other thing it really
20081
14:36:37,200 --> 14:36:38,200
introduced was that 53 byte long info
20082
14:36:40,616 --> 14:36:41,616
cell
20083
14:36:43,380 --> 14:36:44,380
which again can hold video voice and
20084
14:36:46,500 --> 14:36:47,500
data in it
20085
14:36:51,100 --> 14:36:52,100
[Music]
20086
14:36:59,776 --> 14:37:00,776
thank you
20087
14:37:07,256 --> 14:37:08,256
look at the module 9 lesson 2A least
20088
14:37:10,020 --> 14:37:11,020
lines
20089
14:37:11,456 --> 14:37:12,456
I'm gonna look at T1 E1 T3 E3 and sonnet
20090
14:37:16,980 --> 14:37:17,980
synchronized Optical networking
20091
14:37:19,740 --> 14:37:20,740
these are a syllabus talking points so
20092
14:37:22,200 --> 14:37:23,200
kind of need to cover some of the things
20093
14:37:23,580 --> 14:37:24,580
I think could come up it's uh Ali you've
20094
14:37:26,520 --> 14:37:27,520
got a lot of choices when you want to
20095
14:37:28,500 --> 14:37:29,500
connect your small office or even a
20096
14:37:30,596 --> 14:37:31,596
larger office
20097
14:37:32,340 --> 14:37:33,340
across to the internet or to another
20098
14:37:34,500 --> 14:37:35,500
remote office somewhere else that you
20099
14:37:36,540 --> 14:37:37,540
own
20100
14:37:38,936 --> 14:37:39,936
now one of these options is a lease line
20101
14:37:41,400 --> 14:37:42,400
which is a dedicated telecoms line
20102
14:37:44,456 --> 14:37:45,456
now you don't install the line it'll be
20103
14:37:46,880 --> 14:37:47,880
the roads will be dug up or wherever
20104
14:37:49,680 --> 14:37:50,680
they put their cables will be
20105
14:37:52,380 --> 14:37:53,380
um all laid by telecoms company and
20106
14:37:55,800 --> 14:37:56,800
you'll release that line for a fixed fee
20107
14:37:58,080 --> 14:37:59,080
usually monthly and you have to sign a
20108
14:38:00,240 --> 14:38:01,240
contract this lease line is available to
20109
14:38:03,060 --> 14:38:04,060
you all of the time 24 7.
20110
14:38:06,596 --> 14:38:07,596
so since this dedicated line it's not
20111
14:38:08,936 --> 14:38:09,936
shared with other users here's an
20112
14:38:11,276 --> 14:38:12,276
illustration it's an image from
20113
14:38:12,956 --> 14:38:13,956
Wikipedia at the bottom you've got
20114
14:38:15,360 --> 14:38:16,360
remote users using the public uh switch
20115
14:38:19,740 --> 14:38:20,740
telephone Network they're dialing in
20116
14:38:22,320 --> 14:38:23,320
I suppose nowadays they'd be using
20117
14:38:24,240 --> 14:38:25,240
broadband and um vpns they could be
20118
14:38:27,060 --> 14:38:28,060
working from anywhere
20119
14:38:28,380 --> 14:38:29,380
but you've got two Regional Offices on
20120
14:38:30,360 --> 14:38:31,360
the left that need a dedicated
20121
14:38:31,680 --> 14:38:32,680
connection of 24 7. they'll go through
20122
14:38:34,616 --> 14:38:35,616
the telecoms network using a lease line
20123
14:38:38,096 --> 14:38:39,096
foreign
20124
14:38:40,680 --> 14:38:41,680
based on the technology the bandwidth of
20125
14:38:43,140 --> 14:38:44,140
a lease line varies typically between
20126
14:38:45,300 --> 14:38:46,300
56k and 2 Meg to be honest there's
20127
14:38:48,360 --> 14:38:49,360
unlikely be using 56k unless you just
20128
14:38:51,000 --> 14:38:52,000
wanted to have
20129
14:38:53,160 --> 14:38:54,160
um like some sort of keyless entry
20130
14:38:54,900 --> 14:38:55,900
system perhaps for a gym where it just
20131
14:38:57,540 --> 14:38:58,540
needs to authenticate people but even
20132
14:39:00,240 --> 14:39:01,240
then the costs are so low now that um
20133
14:39:02,400 --> 14:39:03,400
it's unlikely to be that slow
20134
14:39:05,160 --> 14:39:06,160
okay some advantages we've already said
20135
14:39:07,560 --> 14:39:08,560
it's it's your connection dedicated to
20136
14:39:09,776 --> 14:39:10,776
you and you can choose how you allocate
20137
14:39:11,700 --> 14:39:12,700
that bandwidth if you want to use it
20138
14:39:13,616 --> 14:39:14,616
mainly for video conferencing or some of
20139
14:39:16,860 --> 14:39:17,860
the some of the use disadvantage they
20140
14:39:19,436 --> 14:39:20,436
are quite expensive
20141
14:39:22,320 --> 14:39:23,320
and typically used to connect businesses
20142
14:39:25,740 --> 14:39:26,740
that have a geographically distant
20143
14:39:27,480 --> 14:39:28,480
offices so they tend to be um Somewhere
20144
14:39:30,300 --> 14:39:31,300
Out In The Sticks
20145
14:39:32,040 --> 14:39:33,040
and a bit more difficult to use other
20146
14:39:35,220 --> 14:39:36,220
connections for example a broadband
20147
14:39:37,616 --> 14:39:38,616
connection with a VPN
20148
14:39:40,020 --> 14:39:41,020
always active and like a dial-up
20149
14:39:41,700 --> 14:39:42,700
connection dial-ups are fairly old
20150
14:39:43,800 --> 14:39:44,800
technology now
20151
14:39:45,480 --> 14:39:46,480
and quite expensive
20152
14:39:47,640 --> 14:39:48,640
okay the telecoms company will charge
20153
14:39:50,220 --> 14:39:51,220
you monthly for use of the lease line
20154
14:39:53,000 --> 14:39:54,000
fee varies based upon the distant speed
20155
14:39:56,160 --> 14:39:57,160
of the connection also where you are in
20156
14:39:58,436 --> 14:39:59,436
the world
20157
14:39:59,456 --> 14:40:00,456
um some places the Technologies still
20158
14:40:01,256 --> 14:40:02,256
emerging
20159
14:40:02,520 --> 14:40:03,520
some places still established
20160
14:40:06,060 --> 14:40:07,060
so level level of quality is assured
20161
14:40:08,520 --> 14:40:09,520
it's not as if you can use more
20162
14:40:10,080 --> 14:40:11,080
bandwidth at certain times of the day
20163
14:40:11,756 --> 14:40:12,756
like frame relay and lesser others
20164
14:40:15,360 --> 14:40:16,360
uh quite uh old technology still in
20165
14:40:18,660 --> 14:40:19,660
quite prominent use but the technology
20166
14:40:21,240 --> 14:40:22,240
is quite old originally used to connect
20167
14:40:23,400 --> 14:40:24,400
your mainframes to remote sites
20168
14:40:26,580 --> 14:40:27,580
so a few examples that they mentioned in
20169
14:40:28,380 --> 14:40:29,380
the syllabus the T carrier and e-carrier
20170
14:40:31,320 --> 14:40:32,320
T carrier one e carrier one and then T3
20171
14:40:34,320 --> 14:40:35,320
and E3
20172
14:40:36,540 --> 14:40:37,540
the T1 transmission system originally
20173
14:40:39,900 --> 14:40:40,900
developed by a t
20174
14:40:43,980 --> 14:40:44,980
1 induced introduced back in 1961.
20175
14:40:47,700 --> 14:40:48,700
originally uh developed to to transmit
20176
14:40:50,936 --> 14:40:51,936
24 phone signals at the same time over
20177
14:40:54,480 --> 14:40:55,480
uh the copper wire
20178
14:40:58,200 --> 14:40:59,200
he uses something called TDM time
20179
14:41:00,300 --> 14:41:01,300
divisional multiplexing this mixes up
20180
14:41:02,936 --> 14:41:03,936
the signal in order to use
20181
14:41:05,640 --> 14:41:06,640
um multiple signals over the same
20182
14:41:07,140 --> 14:41:08,140
physical link
20183
14:41:08,580 --> 14:41:09,580
I don't think they go into any detail on
20184
14:41:10,680 --> 14:41:11,680
TDM in the exam there
20185
14:41:15,060 --> 14:41:16,060
so T1 will give you a bandwidth of 1.544
20186
14:41:18,900 --> 14:41:19,900
Meg upstream and downstream so
20187
14:41:22,380 --> 14:41:23,380
synchronous T1 system is used in America
20188
14:41:25,380 --> 14:41:26,380
Japan and South Korea e the e-system is
20189
14:41:28,500 --> 14:41:29,500
generally used in Europe
20190
14:41:31,980 --> 14:41:32,980
the bandwidth level of T1 was originally
20191
14:41:34,560 --> 14:41:35,560
called the digital signal level 1 or DS1
20192
14:41:38,820 --> 14:41:39,820
I mentioned before the T1 line has 24
20193
14:41:41,220 --> 14:41:42,220
channels each channel is called a ds0
20194
14:41:45,840 --> 14:41:46,840
and you could have one two three of
20195
14:41:48,540 --> 14:41:49,540
these channels or all of the channels
20196
14:41:50,220 --> 14:41:51,220
depending on how much you want to pay
20197
14:41:52,140 --> 14:41:53,140
and how much bandwidth you need
20198
14:41:54,060 --> 14:41:55,060
each channel is capable of transmitting
20199
14:41:56,580 --> 14:41:57,580
data at up to 64k
20200
14:42:01,500 --> 14:42:02,500
uh lease line T1 multiple channels
20201
14:42:04,080 --> 14:42:05,080
provide flexibility so I've said you
20202
14:42:06,720 --> 14:42:07,720
could already choose some channels or
20203
14:42:08,220 --> 14:42:09,220
all the channels E1 is the European
20204
14:42:11,580 --> 14:42:12,580
version of T1 however because of the
20205
14:42:14,540 --> 14:42:15,540
infrastructure that was in place at the
20206
14:42:17,040 --> 14:42:18,040
time you could get up to two Meg
20207
14:42:19,756 --> 14:42:20,756
2.048 mag
20208
14:42:22,200 --> 14:42:23,200
this has 32 channels in each Channel's
20209
14:42:24,956 --> 14:42:25,956
capable of transmitting data up to 64k
20210
14:42:27,900 --> 14:42:28,900
you can add them all up and then there's
20211
14:42:30,116 --> 14:42:31,116
a um a signaling Channel also
20212
14:42:33,720 --> 14:42:34,720
T3 is equivalent to bundling together 28
20213
14:42:37,740 --> 14:42:38,740
T1 line so much faster
20214
14:42:40,680 --> 14:42:41,680
also referred to as DS3
20215
14:42:43,916 --> 14:42:44,916
since there are 24 channels the T3 is
20216
14:42:47,520 --> 14:42:48,520
capable of carrying 672 T1 circuits so
20217
14:42:52,436 --> 14:42:53,436
multiple companies will be using these
20218
14:42:54,000 --> 14:42:55,000
it's not likely that B1 companies
20219
14:42:58,980 --> 14:42:59,980
so you get up to
20220
14:43:01,220 --> 14:43:02,220
44.736 megabits per second with the T3
20221
14:43:03,956 --> 14:43:04,956
lease line if you add the whole line
20222
14:43:07,200 --> 14:43:08,200
30 times faster than T1
20223
14:43:09,956 --> 14:43:10,956
E1 is the equivalent to 16 or E3 sorry
20224
14:43:13,200 --> 14:43:14,200
equivalent to 16 E1 lines
20225
14:43:16,580 --> 14:43:17,580
512 E1 channels so you get up to 34.4
20226
14:43:21,000 --> 14:43:22,000
mag there
20227
14:43:23,400 --> 14:43:24,400
so T3 has more bandwidth than E3
20228
14:43:27,360 --> 14:43:28,360
sonnet I think is mentioned in the
20229
14:43:29,580 --> 14:43:30,580
syllabus which is why we've got it here
20230
14:43:31,456 --> 14:43:32,456
synchronous Optical networking this can
20231
14:43:34,436 --> 14:43:35,436
be used as lease lines also but it uses
20232
14:43:36,416 --> 14:43:37,416
fiber cabling instead of copper
20233
14:43:38,936 --> 14:43:39,936
you get um higher bandwidth for that
20234
14:43:40,916 --> 14:43:41,916
obviously because it's using fiber optic
20235
14:43:44,820 --> 14:43:45,820
um the transmission of solid fiber
20236
14:43:47,340 --> 14:43:48,340
networks is specified as Optical carrier
20237
14:43:49,980 --> 14:43:50,980
or OC transmission rates
20238
14:43:53,756 --> 14:43:54,756
oc1 is a transmission line with speeds
20239
14:43:56,756 --> 14:43:57,756
of up to 51.84 Meg
20240
14:43:59,360 --> 14:44:00,360
oc3 you get up to 155.52
20241
14:44:03,660 --> 14:44:04,660
and then OC 12 you get up to 622
20242
14:44:06,980 --> 14:44:07,980
megabits per second
20243
14:44:11,276 --> 14:44:12,276
uh the oc-12 is typically used by your
20244
14:44:13,800 --> 14:44:14,800
isps as a wide area connection you
20245
14:44:16,020 --> 14:44:17,020
wouldn't be using it in a
20246
14:44:17,640 --> 14:44:18,640
and small company for sure
20247
14:44:20,340 --> 14:44:21,340
so we've looked at T1 E1 T1 T3 and E3
20248
14:44:24,416 --> 14:44:25,416
and also solid networking
20249
14:44:27,300 --> 14:44:28,300
thanks for watching
20250
14:44:33,800 --> 14:44:34,800
[Music]
20251
14:44:41,580 --> 14:44:42,580
foreign
20252
14:44:50,116 --> 14:44:51,116
module 9 lesson 2B wavelength division
20253
14:44:53,936 --> 14:44:54,936
multiplexing bit of a mouthful but it's
20254
14:44:57,060 --> 14:44:58,060
a new um
20255
14:44:58,436 --> 14:44:59,436
objective in the network plus exam
20256
14:45:00,900 --> 14:45:01,900
we'll look at what is a wdm
20257
14:45:04,980 --> 14:45:05,980
that he said wmd wdm system course
20258
14:45:08,756 --> 14:45:09,756
length division multiplexing cwdm again
20259
14:45:12,840 --> 14:45:13,840
we love our abbreviations here a dense
20260
14:45:15,360 --> 14:45:16,360
wavelength division multiplexing
20261
14:45:19,980 --> 14:45:20,980
so what is it basically the idea is to
20262
14:45:23,276 --> 14:45:24,276
get the most you can out of what you've
20263
14:45:26,700 --> 14:45:27,700
got and this
20264
14:45:28,800 --> 14:45:29,800
um instance what we've got is a single
20265
14:45:31,020 --> 14:45:32,020
optical fiber and what we need to do is
20266
14:45:33,840 --> 14:45:34,840
is get as many signals to cross this
20267
14:45:37,560 --> 14:45:38,560
fiber at the same time as possible if
20268
14:45:41,040 --> 14:45:42,040
you just had one signal pass in then
20269
14:45:44,220 --> 14:45:45,220
um so the internet would grow into a
20270
14:45:46,020 --> 14:45:47,020
whole basically it allows bi-directional
20271
14:45:48,660 --> 14:45:49,660
Communications over a single fiber so
20272
14:45:51,116 --> 14:45:52,116
two directions
20273
14:45:53,340 --> 14:45:54,340
uh wdm uses a multiplexer which is um
20274
14:45:58,320 --> 14:45:59,320
you'll often see it referred to in
20275
14:45:59,936 --> 14:46:00,936
diagrams as mux mux and then a d
20276
14:46:03,480 --> 14:46:04,480
multiplexer on the other side dmux
20277
14:46:05,700 --> 14:46:06,700
d-e-m-u-x
20278
14:46:10,680 --> 14:46:11,680
so this um if we just go back sorry it
20279
14:46:14,160 --> 14:46:15,160
um
20280
14:46:14,820 --> 14:46:15,820
the multiplexers that the transmitter to
20281
14:46:17,160 --> 14:46:18,160
combine multiple obstacle signals of
20282
14:46:19,800 --> 14:46:20,800
different wavelengths and at the other
20283
14:46:21,840 --> 14:46:22,840
side this needs to be demultiplexed back
20284
14:46:24,240 --> 14:46:25,240
to the original separate signals
20285
14:46:28,040 --> 14:46:29,040
wdm systems mostly used by telecoms
20286
14:46:30,720 --> 14:46:31,720
companies because of the capacity of the
20287
14:46:32,456 --> 14:46:33,456
network and the again the idea is and
20288
14:46:35,700 --> 14:46:36,700
getting more out of less so they can
20289
14:46:37,560 --> 14:46:38,560
expand the network without having to lay
20290
14:46:39,540 --> 14:46:40,540
more fiber optic cables which obviously
20291
14:46:42,060 --> 14:46:43,060
take uh takes a lot of time and money
20292
14:46:46,616 --> 14:46:47,616
wdm they're divided into two types and
20293
14:46:50,580 --> 14:46:51,580
these are based on the wavelength
20294
14:46:51,956 --> 14:46:52,956
patterns that are used CWD
20295
14:46:55,080 --> 14:46:56,080
um and DWD um
20296
14:46:58,800 --> 14:46:59,800
wavelength division multiplexing through
20297
14:47:02,520 --> 14:47:03,520
um dwdm and cwdm these they use multiple
20298
14:47:06,540 --> 14:47:07,540
wavelengths or lights but they differ in
20299
14:47:09,360 --> 14:47:10,360
the spacing I'll show a diagram actually
20300
14:47:11,700 --> 14:47:12,700
in a moment
20301
14:47:13,860 --> 14:47:14,860
um so in the following factors a
20302
14:47:15,540 --> 14:47:16,540
wavelength on the number of channels the
20303
14:47:17,220 --> 14:47:18,220
ability to amplify the multiplex signals
20304
14:47:19,860 --> 14:47:20,860
in the optical space
20305
14:47:22,400 --> 14:47:23,400
cwdm uses a smaller number of channels
20306
14:47:28,616 --> 14:47:29,616
you can use four or eight channels with
20307
14:47:30,840 --> 14:47:31,840
large space in between the channels the
20308
14:47:33,180 --> 14:47:34,180
bandwidth of each channel is
20309
14:47:35,480 --> 14:47:36,480
3.125 gigabits
20310
14:47:41,520 --> 14:47:42,520
so here's an example of cwdm used to
20311
14:47:44,756 --> 14:47:45,756
transporting data within 100 kilometers
20312
14:47:46,740 --> 14:47:47,740
So within a metropolis area
20313
14:47:53,276 --> 14:47:54,276
an example of cwdm is 10 base lx4
20314
14:47:56,756 --> 14:47:57,756
Network it can transmit data at up to 10
20315
14:48:00,840 --> 14:48:01,840
gigabits per second
20316
14:48:03,500 --> 14:48:04,500
cwdm cable televisions actually use this
20317
14:48:06,300 --> 14:48:07,300
where different wavelengths are used for
20318
14:48:07,916 --> 14:48:08,916
the downstream and Upstream signals
20319
14:48:12,300 --> 14:48:13,300
a dense wave then dense wave length
20320
14:48:15,660 --> 14:48:16,660
division multiplexing dwdm uses a large
20321
14:48:18,360 --> 14:48:19,360
number of channels it could be 40 80 or
20322
14:48:21,060 --> 14:48:22,060
160 but they have small spacing between
20323
14:48:24,060 --> 14:48:25,060
the channels and here we go is an
20324
14:48:26,096 --> 14:48:27,096
example from I'll put the link in down
20325
14:48:28,680 --> 14:48:29,680
here you can see the difference here
20326
14:48:30,540 --> 14:48:31,540
between the spacing and obviously the
20327
14:48:32,820 --> 14:48:33,820
numbers
20328
14:48:34,080 --> 14:48:35,080
um
20329
14:48:35,096 --> 14:48:36,096
the numbers are shown in the diagrams
20330
14:48:36,776 --> 14:48:37,776
there cwdm you can see the spacing where
20331
14:48:39,300 --> 14:48:40,300
it's DW DM
20332
14:48:41,340 --> 14:48:42,340
um very hard to see any spacing between
20333
14:48:43,256 --> 14:48:44,256
the channels
20334
14:48:46,740 --> 14:48:47,740
okay the high number of channels was the
20335
14:48:48,720 --> 14:48:49,720
reason for the name dense wave
20336
14:48:53,880 --> 14:48:54,880
typical dwdm system would use one of the
20337
14:48:56,340 --> 14:48:57,340
following 40 channels at 100 gigahertz
20338
14:48:59,096 --> 14:49:00,096
spacing 80 Channels with 50 gigahertz
20339
14:49:02,160 --> 14:49:03,160
space in
20340
14:49:03,720 --> 14:49:04,720
the bandwidth of a single channel is 100
20341
14:49:05,880 --> 14:49:06,880
Gig
20342
14:49:09,300 --> 14:49:10,300
used for transporting data over long
20343
14:49:11,580 --> 14:49:12,580
distances mainly used as the internet
20344
14:49:13,380 --> 14:49:14,380
background so this cable will be laid
20345
14:49:16,200 --> 14:49:17,200
over long stretches and um under the
20346
14:49:19,256 --> 14:49:20,256
ocean
20347
14:49:21,000 --> 14:49:22,000
into interconnects large strategic
20348
14:49:23,400 --> 14:49:24,400
computer networks and core routers
20349
14:49:26,040 --> 14:49:27,040
all right so we looked at what is wdm
20350
14:49:28,256 --> 14:49:29,256
the system and cwdm
20351
14:49:32,116 --> 14:49:33,116
dndm no dwdm sorry typo
20352
14:49:36,480 --> 14:49:37,480
all right that's all for now thanks for
20353
14:49:38,096 --> 14:49:39,096
watching
20354
14:49:44,130 --> 14:49:45,130
[Music]
20355
14:50:00,000 --> 14:50:01,000
welcome to module 9 lesson 2C uh
20356
14:50:03,180 --> 14:50:04,180
multi-protocol label switching mpls
20357
14:50:08,240 --> 14:50:09,240
so what is it a label switch path
20358
14:50:11,700 --> 14:50:12,700
benefits tunneling
20359
14:50:13,780 --> 14:50:14,780
[Music]
20360
14:50:15,300 --> 14:50:16,300
it's just an overview really because
20361
14:50:16,860 --> 14:50:17,860
they mention it once in brief in the
20362
14:50:20,040 --> 14:50:21,040
syllabus
20363
14:50:21,300 --> 14:50:22,300
but an mperls Network it provides one
20364
14:50:24,416 --> 14:50:25,416
connectivity between two geographically
20365
14:50:26,456 --> 14:50:27,456
distant offices so it's one of a number
20366
14:50:29,040 --> 14:50:30,040
of methods for connecting across a wide
20367
14:50:32,580 --> 14:50:33,580
area network and obviously each has its
20368
14:50:34,560 --> 14:50:35,560
pros and cons which we'll go into mpls
20369
14:50:38,756 --> 14:50:39,756
it's high performance it's packet
20370
14:50:40,560 --> 14:50:41,560
switching a packet forward in it uses
20371
14:50:43,616 --> 14:50:44,616
labels to address packets in the
20372
14:50:45,360 --> 14:50:46,360
telecoms network
20373
14:50:48,116 --> 14:50:49,116
now uh it's called label switching
20374
14:50:50,580 --> 14:50:51,580
because it makes forwarding decisions of
20375
14:50:52,740 --> 14:50:53,740
the packets based upon the values of the
20376
14:50:55,380 --> 14:50:56,380
labels and as opposed to the usual way
20377
14:50:58,256 --> 14:50:59,256
which is looking at the IP headers
20378
14:51:01,080 --> 14:51:02,080
so this avoids having to look at the
20379
14:51:04,436 --> 14:51:05,436
routing table lookups and all of the
20380
14:51:06,300 --> 14:51:07,300
problems associated associated with uh
20381
14:51:10,616 --> 14:51:11,616
routing table lookups
20382
14:51:12,956 --> 14:51:13,956
cool concept is labels are assigned or
20383
14:51:15,776 --> 14:51:16,776
pushed into Data packets this is the
20384
14:51:18,596 --> 14:51:19,596
packets are labeled the routers in the
20385
14:51:20,276 --> 14:51:21,276
impulse Network make forwarding
20386
14:51:22,436 --> 14:51:23,436
decisions based upon that label
20387
14:51:25,140 --> 14:51:26,140
you're still without having to examine
20388
14:51:26,880 --> 14:51:27,880
the actual packet it's only the label
20389
14:51:28,916 --> 14:51:29,916
has to be examined
20390
14:51:33,000 --> 14:51:34,000
so say remote office say what's the same
20391
14:51:35,276 --> 14:51:36,276
package to remote office B
20392
14:51:38,276 --> 14:51:39,276
and the data sent by a reaches the mpls
20393
14:51:40,800 --> 14:51:41,800
network the data will be labeled just
20394
14:51:43,140 --> 14:51:44,140
like how we'd label
20395
14:51:44,820 --> 14:51:45,820
um a packet if we were sending it by
20396
14:51:46,616 --> 14:51:47,616
shipping
20397
14:51:48,540 --> 14:51:49,540
and then the routers in the mpls network
20398
14:51:50,400 --> 14:51:51,400
will act like a courier service the
20399
14:51:52,616 --> 14:51:53,616
routers do not open the packet they just
20400
14:51:55,380 --> 14:51:56,380
look at the label and decide where to
20401
14:51:57,540 --> 14:51:58,540
send it for the next destination
20402
14:52:00,180 --> 14:52:01,180
process continues until you reach the
20403
14:52:02,580 --> 14:52:03,580
edge of the mpls network when the label
20404
14:52:04,980 --> 14:52:05,980
is removed or popped before being
20405
14:52:07,320 --> 14:52:08,320
forwarded to the remote office B
20406
14:52:10,020 --> 14:52:11,020
here's an example of a mpls network from
20407
14:52:13,616 --> 14:52:14,616
netcerts.net
20408
14:52:16,320 --> 14:52:17,320
the labels in the mpls network have the
20409
14:52:18,660 --> 14:52:19,660
information that tells the routers where
20410
14:52:20,400 --> 14:52:21,400
to forward the packets this is a
20411
14:52:22,320 --> 14:52:23,320
simplified diagram where the IP packet
20412
14:52:25,916 --> 14:52:26,916
has gone across to two routers and then
20413
14:52:28,140 --> 14:52:29,140
it's hitting the mpls network at router
20414
14:52:30,660 --> 14:52:31,660
p e a which adds a label and then the
20415
14:52:34,020 --> 14:52:35,020
label is finally removed at router p e
20416
14:52:37,740 --> 14:52:38,740
Zed
20417
14:52:39,000 --> 14:52:40,000
so there's only three routers involved
20418
14:52:40,680 --> 14:52:41,680
in the mpls network here
20419
14:52:45,776 --> 14:52:46,776
so as I said this is different to the
20420
14:52:48,480 --> 14:52:49,480
traditional routing where each packet's
20421
14:52:50,276 --> 14:52:51,276
header has to be examined each router
20422
14:52:52,860 --> 14:52:53,860
step by step has to do complex lookups
20423
14:52:55,500 --> 14:52:56,500
and obviously deal with all the other
20424
14:52:57,300 --> 14:52:58,300
issues associated with routing
20425
14:53:01,080 --> 14:53:02,080
a label switch pass the data
20426
14:53:03,240 --> 14:53:04,240
transmission in an mpls Network occurs
20427
14:53:06,060 --> 14:53:07,060
through a path called the label switch
20428
14:53:07,500 --> 14:53:08,500
paths
20429
14:53:09,480 --> 14:53:10,480
this is the sequence of labels that each
20430
14:53:11,520 --> 14:53:12,520
and every nose along the path that
20431
14:53:13,380 --> 14:53:14,380
establishes between the source and the
20432
14:53:15,540 --> 14:53:16,540
destination this is all actually set up
20433
14:53:17,756 --> 14:53:18,756
before the data is transmitted
20434
14:53:20,880 --> 14:53:21,880
multi-protocol basically means a number
20435
14:53:22,980 --> 14:53:23,980
of protocols can be used really the only
20436
14:53:25,380 --> 14:53:26,380
protocol left to send over mpls is IP
20437
14:53:28,580 --> 14:53:29,580
and ipx SPX and other such protocols or
20438
14:53:33,416 --> 14:53:34,416
apple talk aren't used anymore at all
20439
14:53:37,040 --> 14:53:38,040
npls is often referred to as layer 2.5
20440
14:53:40,140 --> 14:53:41,140
because it sits between layers 2 and
20441
14:53:43,256 --> 14:53:44,256
layer 3 of The OSI
20442
14:53:46,916 --> 14:53:47,916
some of the benefits not dependent on
20443
14:53:49,256 --> 14:53:50,256
layer two technologies such as ATMs
20444
14:53:52,080 --> 14:53:53,080
sonnet and ethernet
20445
14:53:53,756 --> 14:53:54,756
it can be used to carry different types
20446
14:53:55,616 --> 14:53:56,616
of traffic
20447
14:53:56,596 --> 14:53:57,596
and
20448
14:53:58,220 --> 14:53:59,220
ATMs on it and ethernet frames
20449
14:54:04,800 --> 14:54:05,800
tunneling mpls can control the entire
20450
14:54:07,560 --> 14:54:08,560
path of a packet by tunneling through
20451
14:54:09,360 --> 14:54:10,360
the intermediate routers that span
20452
14:54:11,520 --> 14:54:12,520
multiple segments
20453
14:54:15,596 --> 14:54:16,596
this is a unique feature of mpls it's
20454
14:54:18,360 --> 14:54:19,360
used in provisioning in mpls based vpns
20455
14:54:21,596 --> 14:54:22,596
which is actually outside the syllabus
20456
14:54:25,320 --> 14:54:26,320
all right so we've looked at mpls LSPs
20457
14:54:28,680 --> 14:54:29,680
some of the benefits and we've mentioned
20458
14:54:31,140 --> 14:54:32,140
tunneling we haven't gone into any
20459
14:54:32,456 --> 14:54:33,456
detail obviously that's all for now
20460
14:54:34,860 --> 14:54:35,860
thanks for watching
20461
14:54:40,700 --> 14:54:41,700
[Music]
20462
14:54:56,880 --> 14:54:57,880
welcome to module 9 lesson 2D an
20463
14:55:00,000 --> 14:55:01,000
overview of GSM CDMA and Y Max again
20464
14:55:03,840 --> 14:55:04,840
we're just hitting a few syllabus topics
20465
14:55:06,416 --> 14:55:07,416
that comment here kind of mentioned in
20466
14:55:08,400 --> 14:55:09,400
passing really but they are marked down
20467
14:55:10,080 --> 14:55:11,080
there
20468
14:55:11,160 --> 14:55:12,160
look at what is 2G
20469
14:55:13,860 --> 14:55:14,860
um you may have be familiar with it if
20470
14:55:15,660 --> 14:55:16,660
you've had a a mobile phone or I think
20471
14:55:18,480 --> 14:55:19,480
you call them cellular phones in um
20472
14:55:20,700 --> 14:55:21,700
America perhaps
20473
14:55:22,860 --> 14:55:23,860
enhanced rates for GSM
20474
14:55:25,680 --> 14:55:26,680
LTE long-term Evolution and CDMA
20475
14:55:30,660 --> 14:55:31,660
so what is it it stands for global
20476
14:55:33,360 --> 14:55:34,360
system for mobile Communications
20477
14:55:36,116 --> 14:55:37,116
I used to actually be able to plug an
20478
14:55:38,456 --> 14:55:39,456
adapter
20479
14:55:39,740 --> 14:55:40,740
into your
20480
14:55:42,240 --> 14:55:43,240
um a laptop
20481
14:55:44,756 --> 14:55:45,756
and use a GSM card for accessing the
20482
14:55:49,140 --> 14:55:50,140
internet but it was pretty slow my
20483
14:55:51,660 --> 14:55:52,660
experience was pretty unreliable and
20484
14:55:53,520 --> 14:55:54,520
pretty expensive so not fantastic but um
20485
14:55:56,700 --> 14:55:57,700
if you were desperate it kind of did the
20486
14:55:58,616 --> 14:55:59,616
job developed by European Telecom
20487
14:56:01,320 --> 14:56:02,320
standards Institute
20488
14:56:03,240 --> 14:56:04,240
Etsy
20489
14:56:04,140 --> 14:56:05,140
and this is the protocols for second
20490
14:56:06,060 --> 14:56:07,060
generation the 2G cellular networks
20491
14:56:09,000 --> 14:56:10,000
digital used by mobiles
20492
14:56:11,936 --> 14:56:12,936
the original standard was for 2G
20493
14:56:13,860 --> 14:56:14,860
Wireless telephone technology and it
20494
14:56:15,660 --> 14:56:16,660
became the global standard for mobile
20495
14:56:17,640 --> 14:56:18,640
Communications a bit left behind now
20496
14:56:21,380 --> 14:56:22,380
so GSM is a cellular network that uses
20497
14:56:24,360 --> 14:56:25,360
radio signals for mobile and mobile
20498
14:56:27,116 --> 14:56:28,116
comms
20499
14:56:28,436 --> 14:56:29,436
the cellular network is a mobile network
20500
14:56:30,300 --> 14:56:31,300
that is spread across the land area
20501
14:56:31,860 --> 14:56:32,860
called cells
20502
14:56:33,720 --> 14:56:34,720
one or more fixed transceivers or base
20503
14:56:35,880 --> 14:56:36,880
stations were probably more familiar
20504
14:56:37,800 --> 14:56:38,800
with they provide each cell with network
20505
14:56:39,776 --> 14:56:40,776
coverage obviously
20506
14:56:41,936 --> 14:56:42,936
the further away you are from these base
20507
14:56:43,680 --> 14:56:44,680
stations the poorier signal light is
20508
14:56:45,596 --> 14:56:46,596
until at some point you'll have no
20509
14:56:47,340 --> 14:56:48,340
signal at all
20510
14:56:50,756 --> 14:56:51,756
um we commonly call them mobile phones
20511
14:56:52,680 --> 14:56:53,680
during the cellular network calls
20512
14:56:58,580 --> 14:56:59,580
all right so what is 2G second
20513
14:57:01,140 --> 14:57:02,140
generation as we've said they use radio
20514
14:57:03,480 --> 14:57:04,480
signals developed as a replacement for
20515
14:57:05,456 --> 14:57:06,456
the old cellular network they used
20516
14:57:08,580 --> 14:57:09,580
um analog radio signals so that was a
20517
14:57:11,456 --> 14:57:12,456
real old school and stuff
20518
14:57:14,520 --> 14:57:15,520
they were quite easily hacked into at
20519
14:57:17,160 --> 14:57:18,160
the time you if you had the equipment
20520
14:57:19,080 --> 14:57:20,080
you could listen to people's
20521
14:57:21,540 --> 14:57:22,540
um telephone conversations with a
20522
14:57:23,276 --> 14:57:24,276
scanner
20523
14:57:25,860 --> 14:57:26,860
the original GSM standard was actually
20524
14:57:28,140 --> 14:57:29,140
designed for full duplex voice telephony
20525
14:57:30,540 --> 14:57:31,540
it was just adopted for data later on
20526
14:57:33,140 --> 14:57:34,140
originally operated at 96 bits per
20527
14:57:36,416 --> 14:57:37,416
second
20528
14:57:37,380 --> 14:57:38,380
which is pretty darn slow evolved over
20529
14:57:39,840 --> 14:57:40,840
time to allow Datacom through an
20530
14:57:41,640 --> 14:57:42,640
enhanced GSM technology called Edge or
20531
14:57:44,880 --> 14:57:45,880
enhanced data rates for GSM evolution
20532
14:57:49,800 --> 14:57:50,800
this was considered a pre-3g radio
20533
14:57:53,096 --> 14:57:54,096
technology
20534
14:57:54,776 --> 14:57:55,776
it's part of the itu's 3G definition and
20535
14:57:58,740 --> 14:57:59,740
the idea is it delivers higher rate bits
20536
14:58:00,840 --> 14:58:01,840
per radio channel so it's three times
20537
14:58:03,480 --> 14:58:04,480
faster than ordinary GSM also used for
20538
14:58:06,956 --> 14:58:07,956
internet connections
20539
14:58:09,360 --> 14:58:10,360
a long-term Evolution LTE is today's
20540
14:58:12,720 --> 14:58:13,720
mobile networks used something called um
20541
14:58:14,936 --> 14:58:15,936
LTE
20542
14:58:16,980 --> 14:58:17,980
commonly marketed as 4G you may have
20543
14:58:19,560 --> 14:58:20,560
heard 4G LTE
20544
14:58:22,916 --> 14:58:23,916
high-speed data rate access based on the
20545
14:58:25,916 --> 14:58:26,916
edge and HSPA network Technologies which
20546
14:58:28,980 --> 14:58:29,980
are Legacy
20547
14:58:30,300 --> 14:58:31,300
download speed is 300 Meg upload is 75
20548
14:58:34,140 --> 14:58:35,140
so it's asynchronous
20549
14:58:37,080 --> 14:58:38,080
CDMA is code division multiple access
20550
14:58:42,060 --> 14:58:43,060
this uses a special spread Spectrum
20551
14:58:44,820 --> 14:58:45,820
technology and basically the idea is
20552
14:58:47,456 --> 14:58:48,456
multiple users can communicate
20553
14:58:49,256 --> 14:58:50,256
independently but using the same
20554
14:58:51,060 --> 14:58:52,060
bandwidth and they shouldn't in theory
20555
14:58:53,400 --> 14:58:54,400
be any interference on the connection
20556
14:58:56,520 --> 14:58:57,520
uh represents a second generation 2G
20557
14:59:00,360 --> 14:59:01,360
Digital radio solution
20558
14:59:03,660 --> 14:59:04,660
uses the spectrally efficient technology
20559
14:59:06,416 --> 14:59:07,416
for mobile communication
20560
14:59:09,416 --> 14:59:10,416
all right moving on to Y Max
20561
14:59:12,000 --> 14:59:13,000
worldwide interrupt interoperability for
20562
14:59:15,360 --> 14:59:16,360
microwave access now what do they've
20563
14:59:17,276 --> 14:59:18,276
shortened that one technology is based
20564
14:59:19,860 --> 14:59:20,860
on 802.16 standard which you can look up
20565
14:59:22,500 --> 14:59:23,500
in your own time
20566
14:59:23,820 --> 14:59:24,820
it delivers a wireless Broadband
20567
14:59:26,400 --> 14:59:27,400
Services anytime and anywhere
20568
14:59:28,800 --> 14:59:29,800
here's an image from conique.com
20569
14:59:32,340 --> 14:59:33,340
of indirect access with the outdoor
20570
14:59:35,880 --> 14:59:36,880
customer premise equipment connecting
20571
14:59:37,680 --> 14:59:38,680
through a base station when you've got a
20572
14:59:39,776 --> 14:59:40,776
poor
20573
14:59:40,740 --> 14:59:41,740
um connectivity and but you've got the
20574
14:59:43,020 --> 14:59:44,020
signal goes through multiple paths
20575
14:59:46,020 --> 14:59:47,020
uh the 802.16 standard is developed for
20576
14:59:48,776 --> 14:59:49,776
providing an online science connectivity
20577
14:59:51,116 --> 14:59:52,116
so it'd be quite useful in um
20578
14:59:54,596 --> 14:59:55,596
areas where there's a lot of buildings
20579
14:59:56,640 --> 14:59:57,640
and things in the way trees and other
20580
14:59:59,096 --> 15:00:00,096
buildings and antennas
20581
15:00:00,956 --> 15:00:01,956
why Max is sometimes referred to as
20582
15:00:02,936 --> 15:00:03,936
Wi-Fi on steroids similar to Wi-Fi but
20583
15:00:06,116 --> 15:00:07,116
can provide Broadband access to a large
20584
15:00:08,220 --> 15:00:09,220
area supports Communications over a
20585
15:00:11,160 --> 15:00:12,160
maximum of 30 mile radius
20586
15:00:15,480 --> 15:00:16,480
there are other available for fixed
20587
15:00:17,936 --> 15:00:18,936
usage or mobile
20588
15:00:21,720 --> 15:00:22,720
so why Max is the standard which we've
20589
15:00:24,360 --> 15:00:25,360
already said download speed is up to 37
20590
15:00:27,060 --> 15:00:28,060
Meg and the upload speed is up to 17.
20591
15:00:33,200 --> 15:00:34,200
mobile y next is based on the
20592
15:00:36,680 --> 15:00:37,680
802.16a standard from 2005. and this the
20593
15:00:41,220 --> 15:00:42,220
got a throughput of up to 100 Meg
20594
15:00:44,580 --> 15:00:45,580
so we've covered in brief GSM 2G
20595
15:00:47,096 --> 15:00:48,096
enhanced data rates for GSM
20596
15:00:49,680 --> 15:00:50,680
LTE CDMA and Y Max that's all for now
20597
15:00:54,240 --> 15:00:55,240
thanks for listening
20598
15:00:59,930 --> 15:01:00,930
[Music]
20599
15:01:19,640 --> 15:01:20,640
wide area networks Wan connectivity and
20600
15:01:23,880 --> 15:01:24,880
voice over IP
20601
15:01:26,040 --> 15:01:27,040
in the last module we discussed the
20602
15:01:28,200 --> 15:01:29,200
different types of Wan switching and the
20603
15:01:30,720 --> 15:01:31,720
different transmission technologies some
20604
15:01:33,240 --> 15:01:34,240
of which are going to reappear in this
20605
15:01:34,740 --> 15:01:35,740
module that's because uh transmission
20606
15:01:37,936 --> 15:01:38,936
technologies and connectivity options
20607
15:01:40,616 --> 15:01:41,616
are going to go hand in hand so we're
20608
15:01:43,256 --> 15:01:44,256
going to talk about some of the WAN
20609
15:01:45,480 --> 15:01:46,480
connectivity options that we have
20610
15:01:47,116 --> 15:01:48,116
including a least line
20611
15:01:49,800 --> 15:01:50,800
packet switching which is different from
20612
15:01:53,096 --> 15:01:54,096
circuit switching we've seen in the past
20613
15:01:56,340 --> 15:01:57,340
something called cell relay which is the
20614
15:01:59,520 --> 15:02:00,520
name implies it's related to ATM
20615
15:02:03,116 --> 15:02:04,116
and then we're going to discuss briefly
20616
15:02:05,160 --> 15:02:06,160
voice over IP which is something that
20617
15:02:07,320 --> 15:02:08,320
will come up again but which is more and
20618
15:02:09,416 --> 15:02:10,416
more become a necessary part of our
20619
15:02:11,756 --> 15:02:12,756
networks that is making phone calls over
20620
15:02:15,660 --> 15:02:16,660
our internet Network or our ethernet
20621
15:02:18,840 --> 15:02:19,840
Network rather than over the plain old
20622
15:02:22,080 --> 15:02:23,080
telephone system or public switch
20623
15:02:24,776 --> 15:02:25,776
telephone Network and just to recall
20624
15:02:27,776 --> 15:02:28,776
that's either called pots or pstn that
20625
15:02:31,800 --> 15:02:32,800
was the phone network we used for lots
20626
15:02:34,256 --> 15:02:35,256
and lots of years until we started
20627
15:02:36,180 --> 15:02:37,180
getting more into a why internet wide
20628
15:02:40,740 --> 15:02:41,740
world
20629
15:02:42,660 --> 15:02:43,660
so
20630
15:02:44,160 --> 15:02:45,160
when we talk about voice over IP I want
20631
15:02:46,560 --> 15:02:47,560
to bring up a very important protocol
20632
15:02:48,416 --> 15:02:49,416
called sip if you see sip on the test it
20633
15:02:52,200 --> 15:02:53,200
is going to be directly related to voice
20634
15:02:54,240 --> 15:02:55,240
over IP
20635
15:02:56,936 --> 15:02:57,936
now one of the ways in which wide area
20636
15:02:59,040 --> 15:03:00,040
networks can gain connectivity is
20637
15:03:00,840 --> 15:03:01,840
through a leased line we've seen this in
20638
15:03:02,880 --> 15:03:03,880
the past module at least line is sold to
20639
15:03:06,660 --> 15:03:07,660
a company for a set amount of time thus
20640
15:03:09,300 --> 15:03:10,300
the word least
20641
15:03:11,756 --> 15:03:12,756
now a least line provides steady
20642
15:03:15,500 --> 15:03:16,500
permanently set up connection such as a
20643
15:03:18,720 --> 15:03:19,720
T1 connection or perhaps even a T3
20644
15:03:21,360 --> 15:03:22,360
connection or oc9 connection this
20645
15:03:23,756 --> 15:03:24,756
connection usually allows data voice and
20646
15:03:27,956 --> 15:03:28,956
internet connectivity to pass through it
20647
15:03:30,540 --> 15:03:31,540
now typically these are used for
20648
15:03:32,276 --> 15:03:33,276
establishing a Wan and connecting two
20649
15:03:35,456 --> 15:03:36,456
different geographical locations to One
20650
15:03:38,276 --> 15:03:39,276
Network though this connection is
20651
15:03:40,256 --> 15:03:41,256
permanently there it can only be
20652
15:03:41,700 --> 15:03:42,700
accessed as long as the customer is
20653
15:03:43,436 --> 15:03:44,436
paying the lease for it this is where
20654
15:03:45,596 --> 15:03:46,596
the disadvantage to it is this can be
20655
15:03:47,880 --> 15:03:48,880
pretty expensive to buy a lease for
20656
15:03:49,560 --> 15:03:50,560
because again if I have an office in
20657
15:03:52,436 --> 15:03:53,436
let's say Manhattan and I have an office
20658
15:03:57,840 --> 15:03:58,840
in Houston the idea is I'm leasing a
20659
15:04:01,500 --> 15:04:02,500
direct line
20660
15:04:03,360 --> 15:04:04,360
between the two and as you can imagine
20661
15:04:05,160 --> 15:04:06,160
because I have my own line that's going
20662
15:04:07,200 --> 15:04:08,200
between these it's pretty expensive the
20663
15:04:09,180 --> 15:04:10,180
reason I lease it again is because I'm
20664
15:04:10,980 --> 15:04:11,980
not a telecommunications company I can't
20665
15:04:12,840 --> 15:04:13,840
just lay this cord I need them to lay it
20666
15:04:15,180 --> 15:04:16,180
for me and then I'm going to lease it
20667
15:04:16,916 --> 15:04:17,916
from them
20668
15:04:18,596 --> 15:04:19,596
so the upside to this although that's
20669
15:04:21,776 --> 15:04:22,776
the downside is that it's the most
20670
15:04:24,480 --> 15:04:25,480
secure connection that we have
20671
15:04:27,116 --> 15:04:28,116
now in the last module we talked about a
20672
15:04:30,060 --> 15:04:31,060
t carrier lines and a T1 line can be
20673
15:04:34,020 --> 15:04:35,020
leased and provides a secure connection
20674
15:04:36,000 --> 15:04:37,000
so therefore it is a leased line
20675
15:04:48,060 --> 15:04:49,060
and we also talked about in previous
20676
15:04:49,800 --> 15:04:50,800
lessons switching we talked about how
20677
15:04:52,436 --> 15:04:53,436
important switches were to the
20678
15:04:54,000 --> 15:04:55,000
functionality of a local area network
20679
15:04:55,740 --> 15:04:56,740
they provide a communication path
20680
15:04:57,660 --> 15:04:58,660
between two endpoints and they manage
20681
15:05:00,116 --> 15:05:01,116
that flow of data so that way we don't
20682
15:05:01,860 --> 15:05:02,860
have a bunch of traffic going on in
20683
15:05:04,616 --> 15:05:05,616
effect they basically make sure that
20684
15:05:06,660 --> 15:05:07,660
packet going from one location gets to
20685
15:05:09,000 --> 15:05:10,000
the other and doesn't sort of interrupt
20686
15:05:11,400 --> 15:05:12,400
the flow of all the other packets that
20687
15:05:12,900 --> 15:05:13,900
are going on now in Lan these two
20688
15:05:15,240 --> 15:05:16,240
endpoints aren't very far away from each
20689
15:05:16,980 --> 15:05:17,980
other however on a Wan or a wide area
20690
15:05:19,320 --> 15:05:20,320
network these endpoints could be on
20691
15:05:21,240 --> 15:05:22,240
opposite sides
20692
15:05:23,340 --> 15:05:24,340
the globe and that's why switching is
20693
15:05:25,800 --> 15:05:26,800
such an important topic to understand
20694
15:05:27,000 --> 15:05:28,000
now when it comes to a win or a wide
20695
15:05:29,340 --> 15:05:30,340
area network there are two different
20696
15:05:30,416 --> 15:05:31,416
types of switching there's packet
20697
15:05:32,640 --> 15:05:33,640
switching and there's circuit switching
20698
15:05:35,456 --> 15:05:36,456
packet switching is when the data is
20699
15:05:39,360 --> 15:05:40,360
broken up into smaller chunks
20700
15:05:44,340 --> 15:05:45,340
or
20701
15:05:45,596 --> 15:05:46,596
pockets
20702
15:05:47,096 --> 15:05:48,096
and then they're assigned a source and a
20703
15:05:49,436 --> 15:05:50,436
destination and they stop at different
20704
15:05:51,596 --> 15:05:52,596
nodes along the way
20705
15:05:53,276 --> 15:05:54,276
every packet has these assigned to it
20706
15:05:55,980 --> 15:05:56,980
because they don't always stay in the
20707
15:05:57,720 --> 15:05:58,720
same path as the other packet and I'll
20708
15:06:00,060 --> 15:06:01,060
show you a visual to clarify this in
20709
15:06:01,616 --> 15:06:02,616
just a second they're usually going to
20710
15:06:03,360 --> 15:06:04,360
split up which paths they're going to
20711
15:06:05,580 --> 15:06:06,580
take in order to avoid colliding with
20712
15:06:07,616 --> 15:06:08,616
each other and to make it much faster
20713
15:06:13,860 --> 15:06:14,860
this principle of packet switching is
20714
15:06:16,980 --> 15:06:17,980
sort of similar to a torrent if you
20715
15:06:19,680 --> 15:06:20,680
remember a torrent file if you've ever
20716
15:06:21,660 --> 15:06:22,660
used one
20717
15:06:23,040 --> 15:06:24,040
it contains information about data like
20718
15:06:27,060 --> 15:06:28,060
files and folders that can be
20719
15:06:28,500 --> 15:06:29,500
distributed now if someone torrents a
20720
15:06:31,020 --> 15:06:32,020
file the folders and files within that
20721
15:06:33,116 --> 15:06:34,116
torrent are downloaded to the user's
20722
15:06:35,276 --> 15:06:36,276
computer but the torrents are
20723
15:06:36,956 --> 15:06:37,956
peer-to-peer sharing system they Mark
20724
15:06:39,240 --> 15:06:40,240
almost exactly like packet switching
20725
15:06:40,980 --> 15:06:41,980
does torrents collects packets of data
20726
15:06:43,320 --> 15:06:44,320
from wherever the data is available and
20727
15:06:45,000 --> 15:06:46,000
then reassemble it in the whole file on
20728
15:06:47,220 --> 15:06:48,220
your computer
20729
15:06:48,416 --> 15:06:49,416
in other words you can be downloading
20730
15:06:51,060 --> 15:06:52,060
information for the movie you're
20731
15:06:52,980 --> 15:06:53,980
torrenting or of course the movie that
20732
15:06:55,436 --> 15:06:56,436
you own that you're torrent and we
20733
15:06:56,700 --> 15:06:57,700
wouldn't want to say to do anything
20734
15:06:57,720 --> 15:06:58,720
illegal and what you're doing is you're
20735
15:06:59,756 --> 15:07:00,756
actually taking that information from
20736
15:07:02,276 --> 15:07:03,276
say 5 or 10 or 100 different systems
20737
15:07:06,660 --> 15:07:07,660
that are out there they're all coming
20738
15:07:08,220 --> 15:07:09,220
down into your system and then you're
20739
15:07:11,820 --> 15:07:12,820
compiling it all together
20740
15:07:13,740 --> 15:07:14,740
to make
20741
15:07:15,900 --> 15:07:16,900
one movie
20742
15:07:17,580 --> 15:07:18,580
this isn't unlike Willy Wonka where the
20743
15:07:19,800 --> 15:07:20,800
information goes up into the Wonka
20744
15:07:21,900 --> 15:07:22,900
vision gets split up into a whole bunch
20745
15:07:24,000 --> 15:07:25,000
of little pieces and then gets brought
20746
15:07:25,616 --> 15:07:26,616
back to you except all the little pieces
20747
15:07:27,660 --> 15:07:28,660
don't have to be sent from all the same
20748
15:07:29,700 --> 15:07:30,700
place
20749
15:07:31,140 --> 15:07:32,140
so the benefit of this is that it can go
20750
15:07:34,320 --> 15:07:35,320
a lot faster that's with packet
20751
15:07:36,240 --> 15:07:37,240
switching the downside of course is that
20752
15:07:38,276 --> 15:07:39,276
there's a good chance that the packets
20753
15:07:40,740 --> 15:07:41,740
can be lost along the way now the second
20754
15:07:43,500 --> 15:07:44,500
type of switching is called circuit
20755
15:07:45,720 --> 15:07:46,720
switching this method of switching
20756
15:07:47,580 --> 15:07:48,580
requires dedicated
20757
15:07:49,616 --> 15:07:50,616
physical connections so whereas packet
20758
15:07:52,980 --> 15:07:53,980
we're dealing with data in circuit we're
20759
15:07:56,096 --> 15:07:57,096
dealing with physical connections that
20760
15:07:59,400 --> 15:08:00,400
allow data to be transferred now it can
20761
15:08:02,276 --> 15:08:03,276
be difficult to establish these
20762
15:08:03,596 --> 15:08:04,596
connections but the results are a lot
20763
15:08:05,160 --> 15:08:06,160
more reliable than with packet switching
20764
15:08:07,320 --> 15:08:08,320
with circuit switching the connection
20765
15:08:08,756 --> 15:08:09,756
that's made is dedicated for that
20766
15:08:11,456 --> 15:08:12,456
purpose only in other words I create
20767
15:08:14,640 --> 15:08:15,640
switch over which all the data is going
20768
15:08:21,060 --> 15:08:22,060
to be sent once I'm done with that and
20769
15:08:24,840 --> 15:08:25,840
the transfer is complete I no longer
20770
15:08:27,060 --> 15:08:28,060
need this circuit and so it might be
20771
15:08:28,680 --> 15:08:29,680
switched to allow another computer or
20772
15:08:30,540 --> 15:08:31,540
system to talk to one another now
20773
15:08:32,456 --> 15:08:33,456
there's a very small chance of the data
20774
15:08:34,020 --> 15:08:35,020
getting lost or along the way because
20775
15:08:35,700 --> 15:08:36,700
the circuit switching establishes a
20776
15:08:38,520 --> 15:08:39,520
consistent data transfer however the
20777
15:08:41,160 --> 15:08:42,160
downside is I can't take it from say 10
20778
15:08:43,740 --> 15:08:44,740
different sources instead I have to have
20779
15:08:46,256 --> 15:08:47,256
one sender one receiver and in this case
20780
15:08:49,140 --> 15:08:50,140
because I can't split it up it might
20781
15:08:51,540 --> 15:08:52,540
take longer to find that one connection
20782
15:08:53,340 --> 15:08:54,340
although once that connection is
20783
15:08:55,080 --> 15:08:56,080
established it's a lot stronger so
20784
15:08:57,416 --> 15:08:58,416
here's an example of what packet
20785
15:08:59,520 --> 15:09:00,520
switching might look like the packets
20786
15:09:01,616 --> 15:09:02,616
that are traveling across the network
20787
15:09:02,820 --> 15:09:03,820
are all going on different paths right
20788
15:09:05,096 --> 15:09:06,096
one might be going like this
20789
15:09:09,660 --> 15:09:10,660
one might be going like this the other
20790
15:09:12,416 --> 15:09:13,416
might be going like this
20791
15:09:15,116 --> 15:09:16,116
etc etc
20792
15:09:16,740 --> 15:09:17,740
they're all going to reach the
20793
15:09:18,000 --> 15:09:19,000
destination on the right but they're
20794
15:09:21,116 --> 15:09:22,116
going to do so in a different way if we
20795
15:09:22,740 --> 15:09:23,740
say that this is the source
20796
15:09:24,720 --> 15:09:25,720
and this is the destination
20797
15:09:28,680 --> 15:09:29,680
this is going to alleviate traffic
20798
15:09:30,720 --> 15:09:31,720
Network because as you can imagine
20799
15:09:37,560 --> 15:09:38,560
I don't have to require everything to go
20800
15:09:39,720 --> 15:09:40,720
across this one
20801
15:09:41,936 --> 15:09:42,936
dedicated line instead it can use
20802
15:09:43,616 --> 15:09:44,616
whichever line has the least traffic on
20803
15:09:45,480 --> 15:09:46,480
it at that time and therefore
20804
15:09:46,980 --> 15:09:47,980
everything's going to get there without
20805
15:09:48,660 --> 15:09:49,660
with the least amount of traffic however
20806
15:09:50,640 --> 15:09:51,640
it's also not the most secure way
20807
15:09:52,320 --> 15:09:53,320
because obviously there are a lot more
20808
15:09:54,596 --> 15:09:55,596
points for someone to enter in and
20809
15:09:57,180 --> 15:09:58,180
perhaps steal information or sniff
20810
15:09:59,220 --> 15:10:00,220
information and this packet for instance
20811
15:10:02,040 --> 15:10:03,040
might have been gobbled up by a hacker
20812
15:10:04,500 --> 15:10:05,500
someone who wanted to get the
20813
15:10:06,720 --> 15:10:07,720
information or it somehow just got lost
20814
15:10:08,580 --> 15:10:09,580
so this is where the issues with packet
20815
15:10:10,500 --> 15:10:11,500
switching come in
20816
15:10:12,540 --> 15:10:13,540
now in the last module we talked about
20817
15:10:14,640 --> 15:10:15,640
many of the different transmission
20818
15:10:15,596 --> 15:10:16,596
technologies that Wan has in one of
20819
15:10:17,820 --> 15:10:18,820
those if you recall was ATM or
20820
15:10:22,340 --> 15:10:23,340
asynchronous transfer mode and imagine
20821
15:10:24,840 --> 15:10:25,840
that name asynchronous
20822
15:10:27,956 --> 15:10:28,956
that's important because it's not at the
20823
15:10:29,880 --> 15:10:30,880
same time it's asynchronous now ATM
20824
15:10:32,820 --> 15:10:33,820
splits data packets into these cells and
20825
15:10:36,540 --> 15:10:37,540
these cells again are 53 bytes in order
20826
15:10:39,360 --> 15:10:40,360
to send them now this made data flow
20827
15:10:41,520 --> 15:10:42,520
simple and it did not back up the system
20828
15:10:43,256 --> 15:10:44,256
and didn't cause too much traffic so
20829
15:10:45,416 --> 15:10:46,416
very similar to ATM is what we call cell
20830
15:10:48,720 --> 15:10:49,720
relay
20831
15:10:49,916 --> 15:10:50,916
so relay is a connectivity method that
20832
15:10:52,740 --> 15:10:53,740
breaks data up into equal size cells and
20833
15:10:56,040 --> 15:10:57,040
then sends them to the destination now
20834
15:10:58,080 --> 15:10:59,080
unlike ATM these cells aren't
20835
15:11:00,416 --> 15:11:01,416
necessarily 53 bytes but they're all
20836
15:11:03,540 --> 15:11:04,540
even with each other
20837
15:11:05,096 --> 15:11:06,096
so they're all sent across the network
20838
15:11:07,080 --> 15:11:08,080
and they all
20839
15:11:09,540 --> 15:11:10,540
are even meaning they each have the same
20840
15:11:11,640 --> 15:11:12,640
amount of bytes now the data itself is
20841
15:11:14,160 --> 15:11:15,160
transferred very similar to a method
20842
15:11:15,776 --> 15:11:16,776
that we just talked about in packet
20843
15:11:17,456 --> 15:11:18,456
switching the difference is that packet
20844
15:11:19,256 --> 15:11:20,256
switching doesn't evenly break up the
20845
15:11:20,756 --> 15:11:21,756
packs which could cause some Network
20846
15:11:22,436 --> 15:11:23,436
traffic so cell relay is good for
20847
15:11:24,776 --> 15:11:25,776
simultaneous transfer of data and voice
20848
15:11:27,116 --> 15:11:28,116
meaning it allows me to do voice and
20849
15:11:30,776 --> 15:11:31,776
data
20850
15:11:32,160 --> 15:11:33,160
at the same time however just like with
20851
15:11:35,456 --> 15:11:36,456
packet switching it's not very secure
20852
15:11:37,140 --> 15:11:38,140
and some of the cells could also be
20853
15:11:39,116 --> 15:11:40,116
easily lost along the way now as we all
20854
15:11:41,700 --> 15:11:42,700
know voice over IP has sort of taken the
20855
15:11:45,540 --> 15:11:46,540
World by storm international calling can
20856
15:11:47,700 --> 15:11:48,700
be really really expensive and so voice
20857
15:11:50,340 --> 15:11:51,340
over IP is a way to make calls through
20858
15:11:52,436 --> 15:11:53,436
IP packets or using the internet you
20859
15:11:55,320 --> 15:11:56,320
recall IP packets are part of the TCP
20860
15:11:57,596 --> 15:11:58,596
Suite they involve giving every single
20861
15:12:00,480 --> 15:12:01,480
device on a network and IP address which
20862
15:12:02,820 --> 15:12:03,820
is just like a phone number in an old
20863
15:12:04,680 --> 15:12:05,680
system and uh this would allow us to
20864
15:12:08,936 --> 15:12:09,936
save money on international calls it's
20865
15:12:11,756 --> 15:12:12,756
by far cheaper alternative to a phone
20866
15:12:13,740 --> 15:12:14,740
service because unlike a phone service
20867
15:12:15,740 --> 15:12:16,740
there are no monthly bills to pay and
20868
15:12:18,480 --> 15:12:19,480
there are no long distance charges to
20869
15:12:20,700 --> 15:12:21,700
deal with so VoIP uses the existing
20870
15:12:23,456 --> 15:12:24,456
internet infrastructure that's already
20871
15:12:24,900 --> 15:12:25,900
in place to make connections for calls
20872
15:12:27,360 --> 15:12:28,360
and what it does is it
20873
15:12:29,040 --> 15:12:30,040
basically puts the information from your
20874
15:12:31,860 --> 15:12:32,860
voice into packets and streams those
20875
15:12:34,200 --> 15:12:35,200
across a network now like almost
20876
15:12:36,720 --> 15:12:37,720
everything in Computing there is a
20877
15:12:38,400 --> 15:12:39,400
protocol that allows this to work and
20878
15:12:40,740 --> 15:12:41,740
that is called the session initiation
20879
15:12:43,616 --> 15:12:44,616
protocol
20880
15:12:45,060 --> 15:12:46,060
or sip
20881
15:12:46,740 --> 15:12:47,740
write that out
20882
15:12:52,616 --> 15:12:53,616
now if you see sip on the test or if you
20883
15:12:55,256 --> 15:12:56,256
see voice over IP on the test you can be
20884
15:12:58,560 --> 15:12:59,560
guaranteed they're related the other
20885
15:13:00,660 --> 15:13:01,660
thing you're going to see when it comes
20886
15:13:02,580 --> 15:13:03,580
to voice over p is called qos or quality
20887
15:13:08,936 --> 15:13:09,936
of
20888
15:13:10,740 --> 15:13:11,740
service the reason is we want to make
20889
15:13:13,080 --> 15:13:14,080
sure the quality is pretty good
20890
15:13:14,400 --> 15:13:15,400
otherwise if we're getting the packet at
20891
15:13:17,096 --> 15:13:18,096
the end you know if we're getting uh if
20892
15:13:18,900 --> 15:13:19,900
I say a sentence and I get the end of
20893
15:13:20,276 --> 15:13:21,276
the sentence before I get the beginning
20894
15:13:21,240 --> 15:13:22,240
of the sentence then the quality is not
20895
15:13:22,616 --> 15:13:23,616
really good and I can't really rely on
20896
15:13:24,360 --> 15:13:25,360
this so getting back to sip for a second
20897
15:13:26,820 --> 15:13:27,820
this is the protocol that's designed to
20898
15:13:29,096 --> 15:13:30,096
set up and maintain internet multimedia
20899
15:13:31,560 --> 15:13:32,560
sessions such as voice calls it's also
20900
15:13:34,980 --> 15:13:35,980
responsible for communication that's
20901
15:13:36,720 --> 15:13:37,720
used in video and audio conferencing
20902
15:13:39,480 --> 15:13:40,480
online games voice Chats on the internet
20903
15:13:42,060 --> 15:13:43,060
and so on so it's extremely important
20904
15:13:44,700 --> 15:13:45,700
and without it basically VoIP wouldn't
20905
15:13:46,680 --> 15:13:47,680
function
20906
15:13:47,700 --> 15:13:48,700
so here's an example of what VoIP might
20907
15:13:50,640 --> 15:13:51,640
look like as you can see there's both a
20908
15:13:53,820 --> 15:13:54,820
phone and a computer that are connected
20909
15:13:55,860 --> 15:13:56,860
to this network on the top end
20910
15:13:57,956 --> 15:13:58,956
PC connects through a modem or perhaps
20911
15:14:00,840 --> 15:14:01,840
even a network card
20912
15:14:03,300 --> 15:14:04,300
and the telephone connects through some
20913
15:14:06,000 --> 15:14:07,000
sort of adapter and they both connect
20914
15:14:07,916 --> 15:14:08,916
through the internet generally there's
20915
15:14:09,660 --> 15:14:10,660
also one box that everything sort of
20916
15:14:11,700 --> 15:14:12,700
connects into and that sends it out into
20917
15:14:14,700 --> 15:14:15,700
the internet out to your internet
20918
15:14:17,096 --> 15:14:18,096
service provider and again the important
20919
15:14:19,560 --> 15:14:20,560
thing here is that everything is being
20920
15:14:21,060 --> 15:14:22,060
captured into IP packets so your voice
20921
15:14:23,520 --> 15:14:24,520
is being turned into for lack of a
20922
15:14:26,276 --> 15:14:27,276
better term data in an IP packet which
20923
15:14:28,500 --> 15:14:29,500
can then be sent over the internet
20924
15:14:31,680 --> 15:14:32,680
great so now we've identified some Wan
20925
15:14:34,200 --> 15:14:35,200
connectivity options including a leased
20926
15:14:36,300 --> 15:14:37,300
line which is a line that you lease
20927
15:14:38,400 --> 15:14:39,400
between two places an example of that
20928
15:14:41,340 --> 15:14:42,340
would be that T1 or that T3 line the
20929
15:14:44,276 --> 15:14:45,276
reason it's leased is we don't actually
20930
15:14:45,360 --> 15:14:46,360
put it in the Telecommunications Company
20931
15:14:47,040 --> 15:14:48,040
does that for us we simply lease it for
20932
15:14:49,140 --> 15:14:50,140
a certain amount of time it's very
20933
15:14:50,820 --> 15:14:51,820
expensive and so a lot of companies
20934
15:14:52,320 --> 15:14:53,320
don't use lease lines unless they
20935
15:14:53,756 --> 15:14:54,756
require one what they use instead is a
20936
15:14:55,560 --> 15:14:56,560
connection to the internet and then they
20937
15:14:57,180 --> 15:14:58,180
will have uh basically virtual private
20938
15:15:00,116 --> 15:15:01,116
networks and software and other Hardware
20939
15:15:01,740 --> 15:15:02,740
that create a virtual leased line over a
20940
15:15:05,880 --> 15:15:06,880
public line we also talked about packet
20941
15:15:08,096 --> 15:15:09,096
switching which was important different
20942
15:15:09,840 --> 15:15:10,840
from circuit switching which is sort of
20943
15:15:12,300 --> 15:15:13,300
what switches do pocket switching would
20944
15:15:14,456 --> 15:15:15,456
allow me to send
20945
15:15:16,200 --> 15:15:17,200
data and if I had many different routes
20946
15:15:19,256 --> 15:15:20,256
for that data to take it could take any
20947
15:15:21,956 --> 15:15:22,956
one of those pack those those data
20948
15:15:23,820 --> 15:15:24,820
packets run in sort of any different
20949
15:15:26,400 --> 15:15:27,400
configuration I wanted it to and it
20950
15:15:29,040 --> 15:15:30,040
would all arrive at the enemy put back
20951
15:15:30,596 --> 15:15:31,596
together so the packets all basically
20952
15:15:33,116 --> 15:15:34,116
get broken up sent out
20953
15:15:35,240 --> 15:15:36,240
shuffled sent in whatever order they
20954
15:15:37,560 --> 15:15:38,560
need in the packet each packet has the
20955
15:15:40,800 --> 15:15:41,800
source and the destination and also it
20956
15:15:44,276 --> 15:15:45,276
has a number basically
20957
15:15:48,360 --> 15:15:49,360
so that way at the end it knows how to
20958
15:15:50,700 --> 15:15:51,700
put it back together in the correct
20959
15:15:51,840 --> 15:15:52,840
order this is somewhat similar to cell
20960
15:15:53,820 --> 15:15:54,820
relay the difference with cell relay
20961
15:15:55,436 --> 15:15:56,436
which is linked sormal to ATM is that
20962
15:15:57,956 --> 15:15:58,956
all packets
20963
15:16:00,060 --> 15:16:01,060
are the same
20964
15:16:03,540 --> 15:16:04,540
size
20965
15:16:05,040 --> 15:16:06,040
we also briefly which we'll talk about
20966
15:16:06,660 --> 15:16:07,660
more discussed VoIP or voice over IP
20967
15:16:10,256 --> 15:16:11,256
which allows us to make
20968
15:16:13,860 --> 15:16:14,860
phone calls or voice calls
20969
15:16:17,400 --> 15:16:18,400
over the Internet or using ethernet
20970
15:16:20,700 --> 15:16:21,700
technology the protocol that allows us
20971
15:16:23,220 --> 15:16:24,220
to occur is called sip or the session
20972
15:16:31,500 --> 15:16:32,500
initiation
20973
15:16:34,020 --> 15:16:35,020
protocol again if you see sip on the
20974
15:16:36,720 --> 15:16:37,720
test you can guarantee that it has to do
20975
15:16:38,580 --> 15:16:39,580
with VoIP or voice over IP now in the
20976
15:16:41,580 --> 15:16:42,580
net next lesson we're going to talk more
20977
15:16:43,616 --> 15:16:44,616
about remote networking obviously
20978
15:16:45,776 --> 15:16:46,776
something more and more of us need to do
20979
15:16:47,160 --> 15:16:48,160
with telecommuting and also something
20980
15:16:48,956 --> 15:16:49,956
that would allow us to replace for
20981
15:16:50,580 --> 15:16:51,580
instance a leased line with more of a
20982
15:16:52,560 --> 15:16:53,560
temporary solution
20983
15:16:57,140 --> 15:16:58,140
[Music]
20984
15:17:06,436 --> 15:17:07,436
thank you
20985
15:17:14,040 --> 15:17:15,040
welcome to module 9 lesson 4.1
20986
15:17:17,160 --> 15:17:18,160
practicals and services uh as usual
20987
15:17:19,916 --> 15:17:20,916
covering the things we haven't already
20988
15:17:21,360 --> 15:17:22,360
gone over
20989
15:17:23,820 --> 15:17:24,820
it's a wonder wide area network still
20990
15:17:25,916 --> 15:17:26,916
we're in brief I.E the stuff I think you
20991
15:17:28,916 --> 15:17:29,916
need to know because there's entire
20992
15:17:30,480 --> 15:17:31,480
books on some of these protocols PPP
20993
15:17:34,800 --> 15:17:35,800
PPP over ethernet
20994
15:17:38,700 --> 15:17:39,700
Dynamic multi-point VPN which has
20995
15:17:40,980 --> 15:17:41,980
actually just been brought into the
20996
15:17:42,300 --> 15:17:43,300
Cisco CCNA syllabus
20997
15:17:45,116 --> 15:17:46,116
sip trunks uh Josh talked about sip
20998
15:17:48,300 --> 15:17:49,300
trunks earlier
20999
15:17:50,160 --> 15:17:51,160
uh briefly it he actually wrote it onto
21000
15:17:52,980 --> 15:17:53,980
one of the slides when he talked about
21001
15:17:54,180 --> 15:17:55,180
voice so I'll just cover an extra little
21002
15:17:56,220 --> 15:17:57,220
bit
21003
15:17:57,596 --> 15:17:58,596
PPP very popular over dedicated and
21004
15:18:00,900 --> 15:18:01,900
circuit switch links for wide area
21005
15:18:02,936 --> 15:18:03,936
connection
21006
15:18:05,220 --> 15:18:06,220
now where the typical question you would
21007
15:18:07,740 --> 15:18:08,740
get certainly for Cisco is if you're
21008
15:18:09,956 --> 15:18:10,956
collecting a Cisco to a device over a
21009
15:18:12,776 --> 15:18:13,776
wide area network to a non-cisco device
21010
15:18:14,640 --> 15:18:15,640
what protocol would you use you'd
21011
15:18:17,160 --> 15:18:18,160
probably use PPP
21012
15:18:19,680 --> 15:18:20,680
because it's a vendor neutral anyone can
21013
15:18:24,240 --> 15:18:25,240
use it whereas Cisco has a their own set
21014
15:18:27,060 --> 15:18:28,060
of protocols that you can choose from
21015
15:18:28,916 --> 15:18:29,916
for your server-wide area networks also
21016
15:18:32,220 --> 15:18:33,220
works over many different link types so
21017
15:18:34,456 --> 15:18:35,456
synchronous ISDN asynchronous DSL Etc
21018
15:18:39,840 --> 15:18:40,840
two components inside
21019
15:18:42,436 --> 15:18:43,436
PPP you've got your ncps which show your
21020
15:18:45,720 --> 15:18:46,720
network control protocols these
21021
15:18:47,936 --> 15:18:48,936
interface with the TCP or network layer
21022
15:18:50,820 --> 15:18:51,820
talking about OSI and then you've got
21023
15:18:53,340 --> 15:18:54,340
link control protocols this manages the
21024
15:18:55,916 --> 15:18:56,916
data link sessions and connections
21025
15:18:58,256 --> 15:18:59,256
that'd be a typical exam type question
21026
15:19:03,116 --> 15:19:04,116
the other thing about PPP is it offers
21027
15:19:05,520 --> 15:19:06,520
authentication built in which is very
21028
15:19:07,380 --> 15:19:08,380
useful
21029
15:19:09,060 --> 15:19:10,060
now you've got two types pap
21030
15:19:12,000 --> 15:19:13,000
and chap
21031
15:19:14,220 --> 15:19:15,220
uh unfortunately if we go over to
21032
15:19:17,220 --> 15:19:18,220
password authenticate Authentication
21033
15:19:19,560 --> 15:19:20,560
Protocol
21034
15:19:20,840 --> 15:19:21,840
your password if you sniffed the packet
21035
15:19:24,300 --> 15:19:25,300
been sent over the line
21036
15:19:26,340 --> 15:19:27,340
uh the fields you would see
21037
15:19:34,380 --> 15:19:35,380
password it doesn't encrypt the password
21038
15:19:37,800 --> 15:19:38,800
chap
21039
15:19:40,256 --> 15:19:41,256
actually sends a hashed value
21040
15:19:43,800 --> 15:19:44,800
of
21041
15:19:45,140 --> 15:19:46,140
characters whatever they may be
21042
15:19:50,400 --> 15:19:51,400
so you don't actually see the password
21043
15:19:52,140 --> 15:19:53,140
so this is the one you're going to want
21044
15:19:54,000 --> 15:19:55,000
to use no one really is going to use Pap
21045
15:19:55,800 --> 15:19:56,800
anymore unless it's um you can configure
21046
15:19:58,380 --> 15:19:59,380
it if for any reason chap goes down you
21047
15:20:02,096 --> 15:20:03,096
can configure it's a it's called a full
21048
15:20:04,680 --> 15:20:05,680
back PPP fullback but really you'd
21049
15:20:08,040 --> 15:20:09,040
probably rather just have your PPP line
21050
15:20:10,256 --> 15:20:11,256
go down and you troubleshoot it
21051
15:20:12,480 --> 15:20:13,480
but search up is what you will want to
21052
15:20:14,220 --> 15:20:15,220
use because it offers the encryption
21053
15:20:16,200 --> 15:20:17,200
there's a three-way handshake this is
21054
15:20:18,416 --> 15:20:19,416
another typical exam question
21055
15:20:20,936 --> 15:20:21,936
um and you can see it in the diagram
21056
15:20:22,140 --> 15:20:23,140
here there's a challenge a response and
21057
15:20:25,020 --> 15:20:26,020
then it's accepted or rejected if it's
21058
15:20:26,820 --> 15:20:27,820
accepted then the line comes up and you
21059
15:20:29,756 --> 15:20:30,756
can pass then your data if um it's
21060
15:20:33,180 --> 15:20:34,180
rejected then obviously the PPP session
21061
15:20:35,640 --> 15:20:36,640
uh won't come up and I spent some time
21062
15:20:38,956 --> 15:20:39,956
debugging this when I work for Cisco
21063
15:20:41,040 --> 15:20:42,040
Systems
21064
15:20:42,596 --> 15:20:43,596
a continual authentication so it doesn't
21065
15:20:44,936 --> 15:20:45,936
just do it once I'm not sure you'd have
21066
15:20:47,400 --> 15:20:48,400
to read the RFC and see how it's been
21067
15:20:49,436 --> 15:20:50,436
implemented but there's regular
21068
15:20:50,756 --> 15:20:51,756
challenges take place during the session
21069
15:20:53,116 --> 15:20:54,116
uh usually there's a a host name and
21070
15:20:56,096 --> 15:20:57,096
password for example the host name of
21071
15:20:58,256 --> 15:20:59,256
this router is router B
21072
15:21:00,240 --> 15:21:01,240
and you would configure on this side
21073
15:21:02,400 --> 15:21:03,400
here you would say the host the username
21074
15:21:04,740 --> 15:21:05,740
that's permitted is router a and I've
21075
15:21:07,500 --> 15:21:08,500
just used a simple password so what
21076
15:21:09,300 --> 15:21:10,300
happens is this router's host name acts
21077
15:21:11,456 --> 15:21:12,456
as the Authentication
21078
15:21:13,200 --> 15:21:14,200
a hostname it calls using its um host
21079
15:21:18,300 --> 15:21:19,300
name here and its password and in the
21080
15:21:21,900 --> 15:21:22,900
database over here you've configured
21081
15:21:24,060 --> 15:21:25,060
that as the parameters that's going to
21082
15:21:26,160 --> 15:21:27,160
be permitted
21083
15:21:27,900 --> 15:21:28,900
you can do it in a lot more complicated
21084
15:21:29,700 --> 15:21:30,700
ways
21085
15:21:30,956 --> 15:21:31,956
the commands on a Cisco router are PPP
21086
15:21:34,200 --> 15:21:35,200
authentication chap uh or if you want to
21087
15:21:37,140 --> 15:21:38,140
use um and
21088
15:21:39,180 --> 15:21:40,180
um your clear text is pap
21089
15:21:42,116 --> 15:21:43,116
moving on to pppoe it allows
21090
15:21:45,720 --> 15:21:46,720
encapsulating PPP inside ethernet frames
21091
15:21:49,020 --> 15:21:50,020
no surprise really because the clues in
21092
15:21:50,880 --> 15:21:51,880
the name there often used with your DSL
21093
15:21:53,580 --> 15:21:54,580
connections and it tunnels to the your
21094
15:21:55,560 --> 15:21:56,560
internet service provider I'm just
21095
15:21:58,256 --> 15:21:59,256
thinking of questions of the last
21096
15:21:59,756 --> 15:22:00,756
because you're not going to have to
21097
15:22:01,320 --> 15:22:02,320
configure this so they may ask a
21098
15:22:04,020 --> 15:22:05,020
question what are the pppoe stage is
21099
15:22:06,540 --> 15:22:07,540
there's a discovery which is obviously
21100
15:22:09,596 --> 15:22:10,596
the um building up the connection
21101
15:22:11,096 --> 15:22:12,096
between the two devices and then the
21102
15:22:13,436 --> 15:22:14,436
actual session where the data is going
21103
15:22:15,416 --> 15:22:16,416
to be sent across the line
21104
15:22:17,160 --> 15:22:18,160
this is the same with most protocols as
21105
15:22:19,320 --> 15:22:20,320
you know
21106
15:22:21,116 --> 15:22:22,116
moving on to Dynamic multi-point vpm
21107
15:22:25,860 --> 15:22:26,860
this allows your remote VPN connections
21108
15:22:28,320 --> 15:22:29,320
to bypass your your headquarters VPN so
21109
15:22:31,980 --> 15:22:32,980
in your traditional
21110
15:22:33,740 --> 15:22:34,740
VPN service your spoke router over here
21111
15:22:38,456 --> 15:22:39,456
say
21112
15:22:40,080 --> 15:22:41,080
um say it's in Las Vegas this is in LA
21113
15:22:43,256 --> 15:22:44,256
and
21114
15:22:45,116 --> 15:22:46,116
um this is in
21115
15:22:47,220 --> 15:22:48,220
where can we have this Atlanta
21116
15:22:51,116 --> 15:22:52,116
a bit of a pain your branch office would
21117
15:22:55,200 --> 15:22:56,200
have to communicate to your headquarters
21118
15:22:58,520 --> 15:22:59,520
in order for the the tunnel to actually
21119
15:23:01,740 --> 15:23:02,740
take place but it'll be routed from here
21120
15:23:03,956 --> 15:23:04,956
to here and obviously if there's
21121
15:23:06,180 --> 15:23:07,180
problems in your headquarters office for
21122
15:23:08,160 --> 15:23:09,160
whatever reason or the line is congested
21123
15:23:10,080 --> 15:23:11,080
your connection won't take place so the
21124
15:23:12,900 --> 15:23:13,900
point of
21125
15:23:13,916 --> 15:23:14,916
um Dynamic multiple in VPN is your
21126
15:23:17,456 --> 15:23:18,456
Branch offices your spoke routers can
21127
15:23:19,916 --> 15:23:20,916
directly make a connection and it
21128
15:23:22,020 --> 15:23:23,020
bypasses your vpn's router
21129
15:23:26,400 --> 15:23:27,400
you do require a hub and spoke topology
21130
15:23:28,380 --> 15:23:29,380
which we spoke about earlier in our
21131
15:23:31,200 --> 15:23:32,200
topology
21132
15:23:32,936 --> 15:23:33,936
topology sessions
21133
15:23:35,580 --> 15:23:36,580
um oh that shouldn't be in there sorry
21134
15:23:37,436 --> 15:23:38,436
about that
21135
15:23:38,936 --> 15:23:39,936
left that in from my last slide
21136
15:23:43,380 --> 15:23:44,380
all right and finally I've got this
21137
15:23:45,980 --> 15:23:46,980
slide here this image from
21138
15:23:49,020 --> 15:23:50,020
um my
21139
15:23:50,480 --> 15:23:51,480
netphone.com.au this explains basically
21140
15:23:53,276 --> 15:23:54,276
how citrunks work especially an
21141
15:23:55,980 --> 15:23:56,980
initiation protocol if you ever hear sip
21142
15:23:58,380 --> 15:23:59,380
or a session initiative initiation
21143
15:24:00,240 --> 15:24:01,240
protocol which Josh mentioned you
21144
15:24:02,756 --> 15:24:03,756
immediately think voice over IP this is
21145
15:24:05,640 --> 15:24:06,640
what enables voice over IP to work
21146
15:24:08,840 --> 15:24:09,840
trunks enable your PBX to send and
21147
15:24:12,180 --> 15:24:13,180
receive calls via the Internet so what
21148
15:24:14,400 --> 15:24:15,400
it does is it takes your
21149
15:24:16,500 --> 15:24:17,500
um the phone your typical phone
21150
15:24:18,360 --> 15:24:19,360
connection
21151
15:24:19,740 --> 15:24:20,740
and acts as a bridge between the
21152
15:24:22,140 --> 15:24:23,140
internet
21153
15:24:24,540 --> 15:24:25,540
that's the
21154
15:24:25,916 --> 15:24:26,916
um the point of this the SIP trunk
21155
15:24:28,860 --> 15:24:29,860
so digital equivalent of a phone line
21156
15:24:32,096 --> 15:24:33,096
enables you to make and voice and or
21157
15:24:35,400 --> 15:24:36,400
video calls video conferencing calls via
21158
15:24:38,096 --> 15:24:39,096
the Internet
21159
15:24:41,040 --> 15:24:42,040
acts as a bridge between your PBX which
21160
15:24:43,800 --> 15:24:44,800
is your phone system that you'd have at
21161
15:24:46,800 --> 15:24:47,800
your um corporate office there and IP
21162
15:24:50,340 --> 15:24:51,340
telephony
21163
15:24:51,660 --> 15:24:52,660
all right so we covered a lot of stuff
21164
15:24:53,220 --> 15:24:54,220
but I think only what you need today and
21165
15:24:55,380 --> 15:24:56,380
it is covered in other presentations as
21166
15:24:57,180 --> 15:24:58,180
well uh by Josh PPP
21167
15:24:59,720 --> 15:25:00,720
pppoe Dynamic multi-point VPN and zip
21168
15:25:02,820 --> 15:25:03,820
Trunks and I've highlighted what I think
21169
15:25:04,916 --> 15:25:05,916
would be the typical exam questions so
21170
15:25:07,740 --> 15:25:08,740
that's all for now thanks for watching
21171
15:25:14,640 --> 15:25:15,640
[Music]
21172
15:25:21,436 --> 15:25:22,436
thank you
21173
15:25:37,740 --> 15:25:38,740
remote access remote networking
21174
15:25:41,220 --> 15:25:42,220
fundamentals
21175
15:25:43,320 --> 15:25:44,320
in the last lesson we talked about wide
21176
15:25:46,436 --> 15:25:47,436
area networks we talked about how they
21177
15:25:49,020 --> 15:25:50,020
can be implemented what their benefits
21178
15:25:50,880 --> 15:25:51,880
are how they transfer information some
21179
15:25:53,756 --> 15:25:54,756
of the Technologies we use and so on and
21180
15:25:55,860 --> 15:25:56,860
so forth now in this lesson we're going
21181
15:25:58,020 --> 15:25:59,020
to talk more about remote networking
21182
15:26:00,596 --> 15:26:01,596
access remote networking in wands
21183
15:26:03,416 --> 15:26:04,416
actually really go hand in hand and if
21184
15:26:05,936 --> 15:26:06,936
you think about it more of what we do
21185
15:26:07,800 --> 15:26:08,800
now more than ever allows us to remote
21186
15:26:10,560 --> 15:26:11,560
in from home to the Wan
21187
15:26:14,400 --> 15:26:15,400
the largest land in the world being the
21188
15:26:16,916 --> 15:26:17,916
wide area network of the internet and
21189
15:26:20,580 --> 15:26:21,580
then access
21190
15:26:22,560 --> 15:26:23,560
our lands at work this really allows us
21191
15:26:25,916 --> 15:26:26,916
to not only get stuff done but is
21192
15:26:28,020 --> 15:26:29,020
changing the landscape of how networking
21193
15:26:32,040 --> 15:26:33,040
the internet and security have
21194
15:26:35,520 --> 15:26:36,520
been created and how we continue to work
21195
15:26:38,276 --> 15:26:39,276
with them so we're going to talk about
21196
15:26:40,560 --> 15:26:41,560
this in this module and in the next
21197
15:26:42,240 --> 15:26:43,240
couple but for this one the first thing
21198
15:26:44,160 --> 15:26:45,160
we want to do is Define what remote
21199
15:26:45,720 --> 15:26:46,720
networking really is then we want to
21200
15:26:48,596 --> 15:26:49,596
identify some of the technologies that
21201
15:26:50,700 --> 15:26:51,700
we see in place when we discuss remote
21202
15:26:52,560 --> 15:26:53,560
networking these include VPN which we've
21203
15:26:55,740 --> 15:26:56,740
already discussed in some raw detail or
21204
15:26:59,220 --> 15:27:00,220
a virtual
21205
15:27:01,200 --> 15:27:02,200
private
21206
15:27:04,616 --> 15:27:05,616
Network
21207
15:27:09,360 --> 15:27:10,360
radius which allows us to authenticate
21208
15:27:14,220 --> 15:27:15,220
users once they connect and Tech acts
21209
15:27:17,820 --> 15:27:18,820
which allows us to keep its all secure
21210
15:27:20,520 --> 15:27:21,520
so these three are used in Enterprise
21211
15:27:23,640 --> 15:27:24,640
settings to allow someone to remote in
21212
15:27:26,756 --> 15:27:27,756
from home and connect to the network at
21213
15:27:30,060 --> 15:27:31,060
work
21214
15:27:30,900 --> 15:27:31,900
so wands are networks that are not
21215
15:27:33,416 --> 15:27:34,416
restrained to one single physical
21216
15:27:35,456 --> 15:27:36,456
location they're typically as we've
21217
15:27:37,680 --> 15:27:38,680
discussed many local area networks that
21218
15:27:39,776 --> 15:27:40,776
are joined together to create one big
21219
15:27:41,756 --> 15:27:42,756
Wham however this isn't the only
21220
15:27:43,916 --> 15:27:44,916
configuration they can have and remote
21221
15:27:45,416 --> 15:27:46,416
networking is something that ties in
21222
15:27:47,040 --> 15:27:48,040
really well with wide area Networks you
21223
15:27:49,380 --> 15:27:50,380
see remote networking is the process of
21224
15:27:51,660 --> 15:27:52,660
connecting to a network without being
21225
15:27:53,880 --> 15:27:54,880
directly attached to it or physically
21226
15:27:56,820 --> 15:27:57,820
present at the site in other words a
21227
15:27:59,700 --> 15:28:00,700
user or group of users can remotely
21228
15:28:02,400 --> 15:28:03,400
connect to a network without actually
21229
15:28:04,500 --> 15:28:05,500
being where the network is established
21230
15:28:06,596 --> 15:28:07,596
so if I were at home and wanted to
21231
15:28:09,416 --> 15:28:10,416
connect to a network say in China I
21232
15:28:11,880 --> 15:28:12,880
could actually connect as though I were
21233
15:28:13,800 --> 15:28:14,800
sitting right in an office in China
21234
15:28:15,480 --> 15:28:16,480
without actually physically being
21235
15:28:17,096 --> 15:28:18,096
present this type of thing comes in
21236
15:28:19,380 --> 15:28:20,380
handy quite a bit
21237
15:28:20,820 --> 15:28:21,820
now remote networking isn't always
21238
15:28:23,096 --> 15:28:24,096
happen between two very distant
21239
15:28:24,840 --> 15:28:25,840
locations in fact it can be used within
21240
15:28:27,116 --> 15:28:28,116
the same building the same room while
21241
15:28:30,116 --> 15:28:31,116
traveling and remote networking not only
21242
15:28:32,456 --> 15:28:33,456
works on a long distance level but on a
21243
15:28:35,160 --> 15:28:36,160
local network as well for instance
21244
15:28:36,956 --> 15:28:37,956
suppose that I'm an administrator in my
21245
15:28:39,720 --> 15:28:40,720
office and I want to access the contents
21246
15:28:42,360 --> 15:28:43,360
of a user's computer where I want to
21247
15:28:44,160 --> 15:28:45,160
restart a server well instead of having
21248
15:28:46,380 --> 15:28:47,380
to get up walk up to the fourth floor or
21249
15:28:48,480 --> 15:28:49,480
down to the basement wherever the server
21250
15:28:50,096 --> 15:28:51,096
is I could simply remote in to the
21251
15:28:52,800 --> 15:28:53,800
server and reboot it from there so you
21252
15:28:55,256 --> 15:28:56,256
can see that it's a huge time saving
21253
15:28:57,300 --> 15:28:58,300
device however it also opens up a lot of
21254
15:29:00,240 --> 15:29:01,240
possibilities for security issues and so
21255
15:29:02,700 --> 15:29:03,700
on so here is an example of what remote
21256
15:29:06,000 --> 15:29:07,000
network connectivity could look like the
21257
15:29:08,640 --> 15:29:09,640
user is in China on the right and they
21258
15:29:10,500 --> 15:29:11,500
need to connect into the network in New
21259
15:29:13,560 --> 15:29:14,560
York here on the left so they're sitting
21260
15:29:16,256 --> 15:29:17,256
at one physical location and they
21261
15:29:18,480 --> 15:29:19,480
connect through a Wan which we're going
21262
15:29:20,700 --> 15:29:21,700
to called the internet the largest Wan
21263
15:29:23,220 --> 15:29:24,220
in the entire world and they remotely
21264
15:29:26,160 --> 15:29:27,160
connect in some sort of way which we'll
21265
15:29:28,256 --> 15:29:29,256
talk about usually through something
21266
15:29:29,400 --> 15:29:30,400
called a VPN using all sorts of public
21267
15:29:34,380 --> 15:29:35,380
networks and eventually they reach the
21268
15:29:37,680 --> 15:29:38,680
router at their corporate office
21269
15:29:41,456 --> 15:29:42,456
and then it's as if they are actually
21270
15:29:44,640 --> 15:29:45,640
sitting there connected into the network
21271
15:29:46,740 --> 15:29:47,740
they can now access resources on local
21272
15:29:49,436 --> 15:29:50,436
clients or even on the server and all
21273
15:29:52,200 --> 15:29:53,200
without physically being at the location
21274
15:29:54,416 --> 15:29:55,416
in New York now there are a lot of terms
21275
15:29:57,180 --> 15:29:58,180
we hear when we talk about remote
21276
15:30:00,000 --> 15:30:01,000
networking and remote access most of
21277
15:30:02,276 --> 15:30:03,276
them end up being acronyms for the sake
21278
15:30:04,800 --> 15:30:05,800
of time and convenience but there are
21279
15:30:06,956 --> 15:30:07,956
three that I want to specifically talk
21280
15:30:08,520 --> 15:30:09,520
about here that we're going to talk
21281
15:30:09,720 --> 15:30:10,720
about in more detail in the coming
21282
15:30:11,340 --> 15:30:12,340
modules the first is VPN or virtual
21283
15:30:15,116 --> 15:30:16,116
private network is this something we've
21284
15:30:16,916 --> 15:30:17,916
talked before and we'll talk about late
21285
15:30:18,300 --> 15:30:19,300
a little bit later but in essence it
21286
15:30:20,756 --> 15:30:21,756
extends a lan or a local area network by
21287
15:30:23,520 --> 15:30:24,520
adding the ability to have remote users
21288
15:30:25,320 --> 15:30:26,320
connect to it the way it does this is by
21289
15:30:28,080 --> 15:30:29,080
using what's called tunneling it
21290
15:30:31,080 --> 15:30:32,080
basically creates a tunnel in a through
21291
15:30:35,096 --> 15:30:36,096
the wide area network
21292
15:30:38,160 --> 15:30:39,160
the internet
21293
15:30:39,416 --> 15:30:40,416
that then I can connect to and through
21294
15:30:41,936 --> 15:30:42,936
so all of my data is traveling through
21295
15:30:45,480 --> 15:30:46,480
this tunnel between the server or the
21296
15:30:48,660 --> 15:30:49,660
corporate office and the client computer
21297
15:30:50,956 --> 15:30:51,956
this way I can make sure that no one
21298
15:30:53,640 --> 15:30:54,640
outside the tunnel or anyone else on the
21299
15:30:55,800 --> 15:30:56,800
network can get in and I can be sure
21300
15:30:58,080 --> 15:30:59,080
that all of my data is kept secure this
21301
15:31:00,776 --> 15:31:01,776
is why it's called a virtual
21302
15:31:03,240 --> 15:31:04,240
private Network it's virtual it's not
21303
15:31:06,116 --> 15:31:07,116
real it's not physical it's definitely
21304
15:31:08,340 --> 15:31:09,340
private because the tunnel makes sure to
21305
15:31:10,200 --> 15:31:11,200
keep everything out now the next term we
21306
15:31:12,360 --> 15:31:13,360
want to talk about is called radius
21307
15:31:14,540 --> 15:31:15,540
radius by the way stands for remote
21308
15:31:17,580 --> 15:31:18,580
authentication dial in user service I'm
21309
15:31:21,596 --> 15:31:22,596
going to write that out here remote
21310
15:31:24,480 --> 15:31:25,480
Authentication
21311
15:31:28,140 --> 15:31:29,140
dial
21312
15:31:30,060 --> 15:31:31,060
in
21313
15:31:33,900 --> 15:31:34,900
U-verse user service now if you notice
21314
15:31:37,140 --> 15:31:38,140
there's a dial in well remote can
21315
15:31:40,320 --> 15:31:41,320
actually be uh
21316
15:31:42,116 --> 15:31:43,116
dialing in using a modem we don't use
21317
15:31:44,580 --> 15:31:45,580
that much anymore but this is an older
21318
15:31:47,340 --> 15:31:48,340
service what this does is it allows us
21319
15:31:49,740 --> 15:31:50,740
to have centralized authorization
21320
15:31:52,080 --> 15:31:53,080
authentication and accounting management
21321
15:31:55,140 --> 15:31:56,140
for computers and users on a remote
21322
15:31:57,720 --> 15:31:58,720
Network
21323
15:31:58,800 --> 15:31:59,800
in other words it allows me to have one
21324
15:32:01,680 --> 15:32:02,680
server that's going to be responsible
21325
15:32:03,596 --> 15:32:04,596
and we're going to call this the radius
21326
15:32:05,640 --> 15:32:06,640
server
21327
15:32:07,020 --> 15:32:08,020
that's responsible for making sure once
21328
15:32:09,360 --> 15:32:10,360
a VPN is established
21329
15:32:11,700 --> 15:32:12,700
that the person on the other end is
21330
15:32:13,616 --> 15:32:14,616
actually someone who should be
21331
15:32:15,060 --> 15:32:16,060
connecting to my network remember I
21332
15:32:17,220 --> 15:32:18,220
don't want to just let anyone connect I
21333
15:32:19,020 --> 15:32:20,020
want to make sure the person who
21334
15:32:20,160 --> 15:32:21,160
connects is someone who belongs to my
21335
15:32:21,540 --> 15:32:22,540
network generally what we'll do is we'll
21336
15:32:23,880 --> 15:32:24,880
have active directories
21337
15:32:26,340 --> 15:32:27,340
which is what Microsoft uses
21338
15:32:30,776 --> 15:32:31,776
to create for instance usernames and
21339
15:32:32,820 --> 15:32:33,820
passwords and we'll link that up or sync
21340
15:32:35,756 --> 15:32:36,756
it with the radius server sometimes this
21341
15:32:38,340 --> 15:32:39,340
is done on a separate um a separate
21342
15:32:41,220 --> 15:32:42,220
server sometimes it's done on the same
21343
15:32:43,256 --> 15:32:44,256
server either way once you connect the
21344
15:32:45,840 --> 15:32:46,840
VPN the VPN then goes to the radius
21345
15:32:48,480 --> 15:32:49,480
server the radius server checks the
21346
15:32:50,640 --> 15:32:51,640
active directory and now I can make sure
21347
15:32:52,616 --> 15:32:53,616
that only users of the network are
21348
15:32:53,936 --> 15:32:54,936
allowed onto my network
21349
15:32:55,380 --> 15:32:56,380
finally we have something called tacax
21350
15:32:57,660 --> 15:32:58,660
or terminal Access Controller access
21351
15:32:59,880 --> 15:33:00,880
control system it's really long I'm not
21352
15:33:02,456 --> 15:33:03,456
going to write it out this is actually a
21353
15:33:04,616 --> 15:33:05,616
replacement for radius there was another
21354
15:33:07,200 --> 15:33:08,200
replacement for radius by the way it was
21355
15:33:09,660 --> 15:33:10,660
called diameter and if you're a math
21356
15:33:11,580 --> 15:33:12,580
whiz you'll notice that radius is half
21357
15:33:15,180 --> 15:33:16,180
of a diameter when we talk about circles
21358
15:33:17,160 --> 15:33:18,160
but diameter wasn't really used much
21359
15:33:19,580 --> 15:33:20,580
tacx on the other hand is a security
21360
15:33:21,720 --> 15:33:22,720
protocol it allows us to validate
21361
15:33:24,060 --> 15:33:25,060
information with the network
21362
15:33:25,380 --> 15:33:26,380
administrator or server and the
21363
15:33:27,596 --> 15:33:28,596
validation is tested when we try to
21364
15:33:29,520 --> 15:33:30,520
connect just like with radius of course
21365
15:33:31,500 --> 15:33:32,500
the benefit is tacx is newer
21366
15:33:34,616 --> 15:33:35,616
and
21367
15:33:36,480 --> 15:33:37,480
more secure than radius so it basically
21368
15:33:40,320 --> 15:33:41,320
does the same thing it's just a little
21369
15:33:42,540 --> 15:33:43,540
more powerful
21370
15:33:44,456 --> 15:33:45,456
all right so this was short but I just
21371
15:33:46,616 --> 15:33:47,616
wanted to give us an overview of remote
21372
15:33:48,060 --> 15:33:49,060
networking and we're going to talk more
21373
15:33:49,560 --> 15:33:50,560
about that in the coming modules so we
21374
15:33:51,416 --> 15:33:52,416
talked about remote networking what it
21375
15:33:52,916 --> 15:33:53,916
is allowing us
21376
15:33:55,680 --> 15:33:56,680
to access a lan
21377
15:33:58,200 --> 15:33:59,200
basically through
21378
15:34:00,180 --> 15:34:01,180
a Wham whether that Wan is the internet
21379
15:34:02,700 --> 15:34:03,700
or public switch telephone Network it
21380
15:34:05,160 --> 15:34:06,160
also allows us to access the LAN
21381
15:34:10,616 --> 15:34:11,616
from a different
21382
15:34:14,220 --> 15:34:15,220
physical
21383
15:34:16,436 --> 15:34:17,436
location
21384
15:34:19,560 --> 15:34:20,560
we can also identify three remote
21385
15:34:22,080 --> 15:34:23,080
networking Technologies the first
21386
15:34:25,500 --> 15:34:26,500
virtual private
21387
15:34:28,500 --> 15:34:29,500
Network
21388
15:34:31,436 --> 15:34:32,436
creates a tunnel
21389
15:34:33,540 --> 15:34:34,540
over the win
21390
15:34:37,560 --> 15:34:38,560
through which we create a virtual
21391
15:34:39,240 --> 15:34:40,240
Network that is also private we also
21392
15:34:41,820 --> 15:34:42,820
talked about radius and tachs both of
21393
15:34:44,456 --> 15:34:45,456
these allow for authentication so we can
21394
15:34:47,580 --> 15:34:48,580
make sure the person who establishes the
21395
15:34:49,500 --> 15:34:50,500
VPN is actually allowed on our Network
21396
15:34:54,960 --> 15:34:55,960
[Music]
21397
15:35:03,500 --> 15:35:04,500
thank you
21398
15:35:15,180 --> 15:35:16,180
remote access remote access and
21399
15:35:18,116 --> 15:35:19,116
implementation
21400
15:35:21,596 --> 15:35:22,596
we've now talked about some of the basic
21401
15:35:23,276 --> 15:35:24,276
information when it comes to remote
21402
15:35:24,596 --> 15:35:25,596
networking and with that base knowledge
21403
15:35:27,360 --> 15:35:28,360
it's going to come into play in this
21404
15:35:28,980 --> 15:35:29,980
module we're going to talk more about
21405
15:35:31,020 --> 15:35:32,020
remote access and how to implement it
21406
15:35:33,180 --> 15:35:34,180
some of the stuff we're going to talk
21407
15:35:34,436 --> 15:35:35,436
about is overview and some of it is
21408
15:35:36,300 --> 15:35:37,300
still pretty basic again you're not
21409
15:35:37,980 --> 15:35:38,980
going to take this information and just
21410
15:35:39,776 --> 15:35:40,776
Implement a network or remote access to
21411
15:35:42,300 --> 15:35:43,300
a network that would take a little more
21412
15:35:44,900 --> 15:35:45,900
leg work and a little more research what
21413
15:35:48,360 --> 15:35:49,360
this is really giving us is an overview
21414
15:35:50,096 --> 15:35:51,096
of how it all functions and what you
21415
15:35:51,720 --> 15:35:52,720
need to know for the exam so we're going
21416
15:35:54,060 --> 15:35:55,060
to talk about remote access as opposed
21417
15:35:56,096 --> 15:35:57,096
to remote networking remember remote
21418
15:35:58,020 --> 15:35:59,020
networking is sort of the act of
21419
15:35:59,936 --> 15:36:00,936
creating the network to allow remote
21420
15:36:02,820 --> 15:36:03,820
access so we're going to talk about what
21421
15:36:04,800 --> 15:36:05,800
it is what it does and the benefits for
21422
15:36:08,276 --> 15:36:09,276
it we're then going to discuss the steps
21423
15:36:10,560 --> 15:36:11,560
of implementing a remote access policy
21424
15:36:13,860 --> 15:36:14,860
or remote access Technologies
21425
15:36:16,740 --> 15:36:17,740
so remote access is a practice that's
21426
15:36:19,980 --> 15:36:20,980
extremely useful and becoming more and
21427
15:36:21,776 --> 15:36:22,776
more popular constantly All Around the
21428
15:36:23,880 --> 15:36:24,880
World in every I.T situation as we've
21429
15:36:27,060 --> 15:36:28,060
mentioned it's a way for someone to
21430
15:36:28,616 --> 15:36:29,616
connect to a corporate land from outs
21431
15:36:30,360 --> 15:36:31,360
from an outside location it's not always
21432
15:36:32,456 --> 15:36:33,456
used in a corporate setting but for the
21433
15:36:34,380 --> 15:36:35,380
most part that is its main use however
21434
15:36:36,840 --> 15:36:37,840
for instance perhaps you wanted to
21435
15:36:38,340 --> 15:36:39,340
remote into your home network or a home
21436
15:36:41,160 --> 15:36:42,160
computer from the office or you wanted
21437
15:36:43,320 --> 15:36:44,320
to remote in from outside your home
21438
15:36:46,080 --> 15:36:47,080
these are things you could set up as
21439
15:36:47,640 --> 15:36:48,640
well
21440
15:36:48,360 --> 15:36:49,360
with remote access you then have the
21441
15:36:50,400 --> 15:36:51,400
ability to connect to a physical Network
21442
15:36:52,020 --> 15:36:53,020
without having to be anywhere near the
21443
15:36:54,720 --> 15:36:55,720
network in fact you could be on the
21444
15:36:56,276 --> 15:36:57,276
other side of the world and still
21445
15:36:57,360 --> 15:36:58,360
connect as though you're sitting at a
21446
15:36:58,916 --> 15:36:59,916
desktop PC on your land now you can
21447
15:37:02,040 --> 15:37:03,040
imagine how this is even going to take
21448
15:37:03,720 --> 15:37:04,720
it to another step where we could start
21449
15:37:05,700 --> 15:37:06,700
to have computers that are on a lan or a
21450
15:37:09,360 --> 15:37:10,360
land that we don't even control or have
21451
15:37:11,700 --> 15:37:12,700
any physical access to at all instead
21452
15:37:14,040 --> 15:37:15,040
all of our Computing will be done
21453
15:37:15,720 --> 15:37:16,720
remotely this is already coming into
21454
15:37:17,820 --> 15:37:18,820
play when we talk about cloud computing
21455
15:37:19,800 --> 15:37:20,800
and things like Amazon's elastic cloud
21456
15:37:24,300 --> 15:37:25,300
which allows you to set up a virtual
21457
15:37:26,520 --> 15:37:27,520
computer on a remote system and then
21458
15:37:29,096 --> 15:37:30,096
remote into it and through remote access
21459
15:37:30,956 --> 15:37:31,956
and connect to it just like you would be
21460
15:37:33,240 --> 15:37:34,240
connecting to the computers though you
21461
15:37:35,096 --> 15:37:36,096
were sitting in front of an actual
21462
15:37:36,296 --> 15:37:37,296
computer now this obviously speaks to
21463
15:37:38,880 --> 15:37:39,880
not only a greatly reduct reduced amount
21464
15:37:42,240 --> 15:37:43,240
of cost but also a lot more flexibility
21465
15:37:44,276 --> 15:37:45,276
because now I can set up a computer
21466
15:37:47,096 --> 15:37:48,096
anywhere in the world and for instance
21467
15:37:49,680 --> 15:37:50,680
if I had 20 computers I could remotely
21468
15:37:51,776 --> 15:37:52,776
access them and I would only need one
21469
15:37:54,616 --> 15:37:55,616
monitor keyboard and mouse
21470
15:37:57,480 --> 15:37:58,480
so you can see where this is really
21471
15:37:59,400 --> 15:38:00,400
going to come into major play
21472
15:38:01,436 --> 15:38:02,436
now we've already seen this before but
21473
15:38:03,060 --> 15:38:04,060
here's another example of what remote
21474
15:38:05,400 --> 15:38:06,400
access might look like I'm at home and I
21475
15:38:09,000 --> 15:38:10,000
want to access the office computer so I
21476
15:38:11,936 --> 15:38:12,936
connect through the internet to the
21477
15:38:14,220 --> 15:38:15,220
router over at the office through
21478
15:38:16,320 --> 15:38:17,320
something called a VPN
21479
15:38:19,020 --> 15:38:20,020
and now it says though I'm sitting there
21480
15:38:21,256 --> 15:38:22,256
working at the office in fact if it
21481
15:38:24,360 --> 15:38:25,360
wasn't for the fact the boss had to see
21482
15:38:26,400 --> 15:38:27,400
my face they would think that I was
21483
15:38:28,740 --> 15:38:29,740
actually there
21484
15:38:29,936 --> 15:38:30,936
so the first step in implementing on
21485
15:38:33,000 --> 15:38:34,000
remote access is assessing it we need to
21486
15:38:36,596 --> 15:38:37,596
before we can set anything up we need to
21487
15:38:38,220 --> 15:38:39,220
know what exactly we are going to set up
21488
15:38:40,680 --> 15:38:41,680
so first you need to review and
21489
15:38:42,116 --> 15:38:43,116
determine all the connections that are
21490
15:38:43,616 --> 15:38:44,616
going in and out of the Lan this means
21491
15:38:45,596 --> 15:38:46,596
deciding how remote users are going to
21492
15:38:47,340 --> 15:38:48,340
connect to the network for instance if I
21493
15:38:49,796 --> 15:38:50,796
want someone to dial in directly they
21494
15:38:52,140 --> 15:38:53,140
could use a modem this is going to go
21495
15:38:53,820 --> 15:38:54,820
over the public switch telephone Network
21496
15:38:55,740 --> 15:38:56,740
or pots the
21497
15:38:58,080 --> 15:38:59,080
plain old telephone system alternatively
21498
15:39:01,080 --> 15:39:02,080
let's say I have a T3 connection
21499
15:39:02,756 --> 15:39:03,756
connecting to corporate Lan out to an
21500
15:39:05,456 --> 15:39:06,456
ISP well then as long as people at home
21501
15:39:08,456 --> 15:39:09,456
have internet access which today they
21502
15:39:11,040 --> 15:39:12,040
basically would and most of them have
21503
15:39:12,360 --> 15:39:13,360
Broadband access they'd be able to
21504
15:39:14,220 --> 15:39:15,220
connect back through their ISP to the
21505
15:39:16,916 --> 15:39:17,916
network
21506
15:39:17,640 --> 15:39:18,640
second we have to understand know
21507
15:39:20,220 --> 15:39:21,220
exactly what applications and systems
21508
15:39:22,020 --> 15:39:23,020
they're going to need for instance I can
21509
15:39:24,540 --> 15:39:25,540
give them access to their computer which
21510
15:39:28,080 --> 15:39:29,080
might be one way to do it but if I have
21511
15:39:30,360 --> 15:39:31,360
a lot of people logging in constantly
21512
15:39:32,520 --> 15:39:33,520
remotely and I need to give them access
21513
15:39:34,380 --> 15:39:35,380
to their computer that's going to be
21514
15:39:35,700 --> 15:39:36,700
pretty difficult to set up and quite
21515
15:39:38,756 --> 15:39:39,756
um
21516
15:39:41,720 --> 15:39:42,720
uncentralized so what I might do is
21517
15:39:44,700 --> 15:39:45,700
create one remote access server RS in
21518
15:39:48,840 --> 15:39:49,840
which uh everyone can connect and get
21519
15:39:51,416 --> 15:39:52,416
their profile or information this also
21520
15:39:54,180 --> 15:39:55,180
goes with something called
21521
15:39:55,400 --> 15:39:56,400
virtualization or
21522
15:39:57,956 --> 15:39:58,956
cloud computing so basically they would
21523
15:40:01,080 --> 15:40:02,080
log on to this very powerful server and
21524
15:40:03,660 --> 15:40:04,660
they would see what looks like their
21525
15:40:05,456 --> 15:40:06,456
computer in fact if I was basically
21526
15:40:07,916 --> 15:40:08,916
doing this all the time I might just do
21527
15:40:09,776 --> 15:40:10,776
this for when they sit at the office
21528
15:40:11,400 --> 15:40:12,400
they just sit at a terminal sort of
21529
15:40:13,380 --> 15:40:14,380
thing turn on the computer and they're
21530
15:40:15,540 --> 15:40:16,540
connecting actually to a server that's
21531
15:40:17,276 --> 15:40:18,276
not even located in the building
21532
15:40:20,160 --> 15:40:21,160
finally I want to determine the number
21533
15:40:21,660 --> 15:40:22,660
of remote users if I'm only giving this
21534
15:40:23,456 --> 15:40:24,456
to say uh the top hun shows at the firm
21535
15:40:27,480 --> 15:40:28,480
that's one thing that's going to be for
21536
15:40:30,000 --> 15:40:31,000
everyone in the entire operation I'm
21537
15:40:32,096 --> 15:40:33,096
going to need to spend a lot more time
21538
15:40:33,360 --> 15:40:34,360
and resources devoted to setting up
21539
15:40:36,000 --> 15:40:37,000
remote access
21540
15:40:37,680 --> 15:40:38,680
now the next thing I have to do is think
21541
15:40:39,240 --> 15:40:40,240
about the considerations and the things
21542
15:40:40,980 --> 15:40:41,980
that are necessary for remote access in
21543
15:40:43,320 --> 15:40:44,320
order to implement for instance the
21544
15:40:45,240 --> 15:40:46,240
first step is to make sure that the
21545
15:40:47,040 --> 15:40:48,040
remote access solution you create is
21546
15:40:48,540 --> 15:40:49,540
flexible enough to support all those
21547
15:40:50,220 --> 15:40:51,220
connections and the users that are that
21548
15:40:51,660 --> 15:40:52,660
you've just established for example if
21549
15:40:53,936 --> 15:40:54,936
one remote user is connected to a T1
21550
15:40:55,916 --> 15:40:56,916
Line and other ones can't get through
21551
15:40:57,540 --> 15:40:58,540
dial up your solution is going to need
21552
15:40:59,456 --> 15:41:00,456
to be able to accommodate both of them
21553
15:41:00,916 --> 15:41:01,916
of course nowadays that's not such an
21554
15:41:03,416 --> 15:41:04,416
issue because everyone has
21555
15:41:05,756 --> 15:41:06,756
um Broadband connections but if they're
21556
15:41:08,456 --> 15:41:09,456
not connecting in the same way or one
21557
15:41:10,380 --> 15:41:11,380
person is going to be connect traveling
21558
15:41:11,820 --> 15:41:12,820
around while most people are going to be
21559
15:41:13,020 --> 15:41:14,020
coming from home well and those are all
21560
15:41:14,756 --> 15:41:15,756
things I need to take into account
21561
15:41:16,560 --> 15:41:17,560
next need to establish some sort of
21562
15:41:19,436 --> 15:41:20,436
centralized access point meaning when
21563
15:41:22,200 --> 15:41:23,200
they hit that router uh if they're
21564
15:41:24,540 --> 15:41:25,540
coming out of the internet into the
21565
15:41:27,116 --> 15:41:28,116
router I need something here that is
21566
15:41:29,096 --> 15:41:30,096
going to centralize all of the stuff
21567
15:41:30,956 --> 15:41:31,956
coming in I also don't want to just give
21568
15:41:32,820 --> 15:41:33,820
them access to the network I might want
21569
15:41:34,256 --> 15:41:35,256
to send them into a separate
21570
15:41:37,796 --> 15:41:38,796
Network temporarily while I make sure
21571
15:41:40,256 --> 15:41:41,256
that they get authenticated perhaps a
21572
15:41:42,060 --> 15:41:43,060
virtual Lan or a Honeypot or something
21573
15:41:45,060 --> 15:41:46,060
so it's important or demilitarized zone
21574
15:41:48,180 --> 15:41:49,180
so it's important that I have some area
21575
15:41:50,640 --> 15:41:51,640
where they can go and understand what
21576
15:41:52,436 --> 15:41:53,436
the central device is going to be in
21577
15:41:54,360 --> 15:41:55,360
some cases we could call this a VPN
21578
15:41:58,220 --> 15:41:59,220
concentrator
21579
15:42:00,116 --> 15:42:01,116
which is basically a device that helps
21580
15:42:02,400 --> 15:42:03,400
set up vpns finally I need to consider
21581
15:42:05,340 --> 15:42:06,340
security when I'm establishing this
21582
15:42:06,840 --> 15:42:07,840
remote system as I mentioned I don't
21583
15:42:08,640 --> 15:42:09,640
just want to give people access to the
21584
15:42:09,956 --> 15:42:10,956
network I want to make sure the people
21585
15:42:11,160 --> 15:42:12,160
on my network connecting wirelessly or
21586
15:42:13,860 --> 15:42:14,860
remotely or physically connecting can
21587
15:42:16,500 --> 15:42:17,500
all connect securely I don't want
21588
15:42:18,540 --> 15:42:19,540
someone to tap into their connection on
21589
15:42:21,240 --> 15:42:22,240
my end or on their end so it's really
21590
15:42:23,756 --> 15:42:24,756
important we take security into account
21591
15:42:25,276 --> 15:42:26,276
nowadays we have a lot of uh
21592
15:42:27,956 --> 15:42:28,956
authentication methods that would
21593
15:42:29,700 --> 15:42:30,700
provide you with say a key ring and on
21594
15:42:32,220 --> 15:42:33,220
that key ring you'll have it what's
21595
15:42:33,720 --> 15:42:34,720
called a token
21596
15:42:35,340 --> 15:42:36,340
the token provides you with say a six
21597
15:42:37,380 --> 15:42:38,380
digit number that randomly alternates
21598
15:42:39,480 --> 15:42:40,480
every minute unless you have the token
21599
15:42:41,640 --> 15:42:42,640
and that token is set up with your
21600
15:42:43,320 --> 15:42:44,320
computer you won't be able to get access
21601
15:42:44,756 --> 15:42:45,756
to the internet these things we've
21602
15:42:46,796 --> 15:42:47,796
talked about in a plus but I'm just
21603
15:42:48,180 --> 15:42:49,180
reviewing them a bit more
21604
15:42:50,340 --> 15:42:51,340
now I also need to have some procedures
21605
15:42:51,720 --> 15:42:52,720
and policies in place so that people
21606
15:42:53,756 --> 15:42:54,756
understand how they're going to be able
21607
15:42:55,080 --> 15:42:56,080
to access and what they're going to be
21608
15:42:56,096 --> 15:42:57,096
able to do
21609
15:42:57,116 --> 15:42:58,116
the policies ensure that the procedures
21610
15:42:59,520 --> 15:43:00,520
are followed and the procedures ensure
21611
15:43:01,616 --> 15:43:02,616
that the safety is used when remoting
21612
15:43:04,680 --> 15:43:05,680
into the system so designing these
21613
15:43:06,956 --> 15:43:07,956
policies is up to the network
21614
15:43:08,936 --> 15:43:09,936
administrator and perhaps this Central
21615
15:43:11,456 --> 15:43:12,456
information officer or the CIO or the
21616
15:43:14,936 --> 15:43:15,936
Chief Information officer now it's
21617
15:43:17,400 --> 15:43:18,400
common to have a system configuration
21618
15:43:18,840 --> 15:43:19,840
that does not allow users to remotely
21619
15:43:21,360 --> 15:43:22,360
access uh the system after a certain
21620
15:43:23,580 --> 15:43:24,580
time at night I might want to do this
21621
15:43:24,900 --> 15:43:25,900
for a number of reasons however the
21622
15:43:27,296 --> 15:43:28,296
policies need to be whatever they are
21623
15:43:29,040 --> 15:43:30,040
well documented and easy to understand I
21624
15:43:32,520 --> 15:43:33,520
need to know exactly how I'm going to
21625
15:43:33,840 --> 15:43:34,840
access stuff otherwise what's going to
21626
15:43:35,400 --> 15:43:36,400
happen is you're going to say hey we
21627
15:43:36,296 --> 15:43:37,296
have remote access and suddenly people
21628
15:43:38,220 --> 15:43:39,220
are going to start calling the help desk
21629
15:43:39,360 --> 15:43:40,360
saying it's not working properly
21630
15:43:41,276 --> 15:43:42,276
we also want to make sure that they're
21631
15:43:42,840 --> 15:43:43,840
accountable if they don't follow
21632
15:43:44,096 --> 15:43:45,096
specific rules policies Etc so I need to
21633
15:43:47,456 --> 15:43:48,456
say if someone remotes in or loses their
21634
15:43:49,320 --> 15:43:50,320
token they could be possibly fired
21635
15:43:52,140 --> 15:43:53,140
because that's a huge security breach
21636
15:43:53,936 --> 15:43:54,936
just like I don't want to give my laptop
21637
15:43:55,500 --> 15:43:56,500
or my token to someone even if it's some
21638
15:43:57,720 --> 15:43:58,720
within the network if I've been told
21639
15:43:58,916 --> 15:43:59,916
specifically to keep it same with
21640
15:44:00,596 --> 15:44:01,596
passwords usernames basically the idea
21641
15:44:02,756 --> 15:44:03,756
is the more ability I give people the
21642
15:44:05,160 --> 15:44:06,160
flexibility I get people to connect it
21643
15:44:07,020 --> 15:44:08,020
also makes it much more of a security
21644
15:44:09,240 --> 15:44:10,240
hazard
21645
15:44:10,380 --> 15:44:11,380
finally you need to make sure Human
21646
15:44:12,240 --> 15:44:13,240
Resources is behind all of your policies
21647
15:44:14,456 --> 15:44:15,456
they're the ones who are going to be
21648
15:44:15,840 --> 15:44:16,840
training everyone and so if HR isn't
21649
15:44:18,240 --> 15:44:19,240
behind you you're going to be in major
21650
15:44:19,616 --> 15:44:20,616
issues and they're going to fight you
21651
15:44:21,116 --> 15:44:22,116
the whole way speaking of Human
21652
15:44:22,860 --> 15:44:23,860
Resources I bet it's pretty fair to say
21653
15:44:25,200 --> 15:44:26,200
that not everyone is going to be
21654
15:44:26,936 --> 15:44:27,936
qualified or knowledgeable to enough to
21655
15:44:30,000 --> 15:44:31,000
connect to remote access so it's really
21656
15:44:32,276 --> 15:44:33,276
important that we train the end users on
21657
15:44:34,916 --> 15:44:35,916
what's happening on their end and how
21658
15:44:36,596 --> 15:44:37,596
the connection works it's a good idea to
21659
15:44:38,640 --> 15:44:39,640
have the remote users learn about what's
21660
15:44:40,140 --> 15:44:41,140
actually happening when they connect and
21661
15:44:42,180 --> 15:44:43,180
how to set up their ends of the
21662
15:44:43,380 --> 15:44:44,380
connections otherwise your help desk is
21663
15:44:45,416 --> 15:44:46,416
going to be inundated with calls and not
21664
15:44:47,456 --> 15:44:48,456
only that but you're gonna have a lot of
21665
15:44:48,416 --> 15:44:49,416
people upset when things aren't working
21666
15:44:49,680 --> 15:44:50,680
properly even if it's something that
21667
15:44:51,296 --> 15:44:52,296
they could easily fix
21668
15:44:52,680 --> 15:44:53,680
so like the job of an admin in any other
21669
15:44:56,040 --> 15:44:57,040
case it falls upon your shoulders to
21670
15:44:58,500 --> 15:44:59,500
help users when there's any sort of
21671
15:45:00,060 --> 15:45:01,060
issue this will become a lot more
21672
15:45:01,860 --> 15:45:02,860
difficult when the admin doesn't go over
21673
15:45:04,320 --> 15:45:05,320
to the user's desk and help them out or
21674
15:45:06,416 --> 15:45:07,416
doesn't have the time to go over
21675
15:45:07,560 --> 15:45:08,560
hundreds people desks you have to
21676
15:45:09,720 --> 15:45:10,720
connect with the user in some other way
21677
15:45:11,456 --> 15:45:12,456
though perhaps it's through a handout or
21678
15:45:13,616 --> 15:45:14,616
through an email or perhaps you remotely
21679
15:45:15,900 --> 15:45:16,900
access their computer or even give the
21680
15:45:18,840 --> 15:45:19,840
computers to them set up already to to
21681
15:45:21,380 --> 15:45:22,380
remotely connect or talk to HR about
21682
15:45:24,000 --> 15:45:25,000
creating some sort of training program
21683
15:45:26,220 --> 15:45:27,220
that's going to help support all of this
21684
15:45:28,616 --> 15:45:29,616
finally once we've set all this up we
21685
15:45:30,660 --> 15:45:31,660
need to monitor the network to make sure
21686
15:45:32,700 --> 15:45:33,700
the remote access is working as intended
21687
15:45:35,220 --> 15:45:36,220
the first step towards doing this is to
21688
15:45:37,860 --> 15:45:38,860
manage all of the entry points that any
21689
15:45:40,500 --> 15:45:41,500
of the users could use it should be kept
21690
15:45:42,840 --> 15:45:43,840
down to one single access point and
21691
15:45:45,480 --> 15:45:46,480
that's important because obviously it's
21692
15:45:46,916 --> 15:45:47,916
easier to manage one access point than
21693
15:45:48,900 --> 15:45:49,900
several father users enter the network
21694
15:45:51,360 --> 15:45:52,360
in the same place it's going to be a lot
21695
15:45:53,160 --> 15:45:54,160
easier to monitor them
21696
15:45:54,596 --> 15:45:55,596
next we need to make sure that the
21697
15:45:56,340 --> 15:45:57,340
policies and procedures are followed so
21698
15:45:58,256 --> 15:45:59,256
when users start using wrong procedures
21699
15:45:59,936 --> 15:46:00,936
don't follow the policies there's a
21700
15:46:01,916 --> 15:46:02,916
really good chance something's going to
21701
15:46:02,936 --> 15:46:03,936
go wrong and it's important to have the
21702
15:46:04,916 --> 15:46:05,916
remote users follow a strict procedure
21703
15:46:07,020 --> 15:46:08,020
in order to avoid any problems and to
21704
15:46:09,180 --> 15:46:10,180
help take the load off of you and the
21705
15:46:10,980 --> 15:46:11,980
help desk
21706
15:46:11,936 --> 15:46:12,936
it's also very important to understand
21707
15:46:14,220 --> 15:46:15,220
everything that's going on within the
21708
15:46:16,500 --> 15:46:17,500
network you have to know where the
21709
15:46:17,936 --> 15:46:18,936
connections are what they're doing what
21710
15:46:20,276 --> 15:46:21,276
the users are up to you have to keep
21711
15:46:22,200 --> 15:46:23,200
track of all of this stuff and there are
21712
15:46:24,000 --> 15:46:25,000
different ways to do this different
21713
15:46:25,256 --> 15:46:26,256
devices we can deploy and software that
21714
15:46:27,180 --> 15:46:28,180
we'll talk about
21715
15:46:29,096 --> 15:46:30,096
so just to recap we've defined what
21716
15:46:31,500 --> 15:46:32,500
remote access is what it is what it does
21717
15:46:35,040 --> 15:46:36,040
and its benefits all in all it allows us
21718
15:46:38,400 --> 15:46:39,400
to again be geographically at a
21719
15:46:41,820 --> 15:46:42,820
different location
21720
15:46:46,040 --> 15:46:47,040
and connect
21721
15:46:51,660 --> 15:46:52,660
to the lamp
21722
15:46:54,180 --> 15:46:55,180
we also talked about lots of the steps
21723
15:46:55,980 --> 15:46:56,980
of implementation and although this
21724
15:46:58,256 --> 15:46:59,256
isn't very technical all this stuff
21725
15:46:59,640 --> 15:47:00,640
comes up on the network plus exam you
21726
15:47:01,680 --> 15:47:02,680
have to know what it is you're supposed
21727
15:47:03,000 --> 15:47:04,000
to do so remember we talked about some
21728
15:47:05,040 --> 15:47:06,040
policies procedures
21729
15:47:07,110 --> 15:47:08,110
[Music]
21730
15:47:09,180 --> 15:47:10,180
training
21731
15:47:13,200 --> 15:47:14,200
and monitoring
21732
15:47:16,436 --> 15:47:17,436
now in the next module we're going to
21733
15:47:18,180 --> 15:47:19,180
talk more specifically about how we set
21734
15:47:19,740 --> 15:47:20,740
some of this stuff up and what we're
21735
15:47:21,060 --> 15:47:22,060
going to do to make sure it works
21736
15:47:22,740 --> 15:47:23,740
properly
21737
15:47:28,280 --> 15:47:29,280
[Music]
21738
15:47:45,360 --> 15:47:46,360
welcome to module 10 lesson 2A a remote
21739
15:47:48,720 --> 15:47:49,720
access methods
21740
15:47:50,820 --> 15:47:51,820
so remote access is all about how you
21741
15:47:53,096 --> 15:47:54,096
can reach various network devices when
21742
15:47:55,616 --> 15:47:56,616
you're not at the physical location
21743
15:47:59,160 --> 15:48:00,160
look at RDP SSH VNC
21744
15:48:03,596 --> 15:48:04,596
telnet management through the https
21745
15:48:09,000 --> 15:48:10,000
and file access and then outer band
21746
15:48:12,720 --> 15:48:13,720
RDP this is uh proprietary to Microsoft
21747
15:48:16,616 --> 15:48:17,616
so they've come up with this software
21748
15:48:18,540 --> 15:48:19,540
you may have seen it before when you can
21749
15:48:21,296 --> 15:48:22,296
um if you check on your Windows machine
21750
15:48:22,936 --> 15:48:23,936
you can normally
21751
15:48:24,956 --> 15:48:25,956
and find the uh
21752
15:48:28,080 --> 15:48:29,080
the button to click that it will allow
21753
15:48:30,596 --> 15:48:31,596
you to connect to a remote computer and
21754
15:48:32,220 --> 15:48:33,220
you might use this if you work in a harp
21755
15:48:33,720 --> 15:48:34,720
desk if you need to support a remote
21756
15:48:36,180 --> 15:48:37,180
user
21757
15:48:38,400 --> 15:48:39,400
you can have remote access and control
21758
15:48:40,436 --> 15:48:41,436
via screen sharing
21759
15:48:43,256 --> 15:48:44,256
this is actually how a lot of scammers
21760
15:48:45,060 --> 15:48:46,060
will
21761
15:48:46,680 --> 15:48:47,680
get people to hand over remote control
21762
15:48:49,500 --> 15:48:50,500
they'll phone somebody who's a bit naive
21763
15:48:52,256 --> 15:48:53,256
and say um we've found a technical floor
21764
15:48:54,416 --> 15:48:55,416
in your computer and Handover can you
21765
15:48:57,660 --> 15:48:58,660
hand over access so we can fix it
21766
15:49:00,540 --> 15:49:01,540
typical exam question would be what port
21767
15:49:03,416 --> 15:49:04,416
does it use it's TCP it has to be
21768
15:49:05,520 --> 15:49:06,520
reliable obviously and the port is three
21769
15:49:07,860 --> 15:49:08,860
three eight nine
21770
15:49:09,360 --> 15:49:10,360
you need to know this kind of stuff if
21771
15:49:10,916 --> 15:49:11,916
you need to permit this through your
21772
15:49:12,956 --> 15:49:13,956
firewall
21773
15:49:14,160 --> 15:49:15,160
or deny obviously
21774
15:49:16,256 --> 15:49:17,256
now the client side can be Windows Mac
21775
15:49:18,840 --> 15:49:19,840
or Linux there's a few different
21776
15:49:20,480 --> 15:49:21,480
operating systems that are supported
21777
15:49:24,660 --> 15:49:25,660
SSH
21778
15:49:26,820 --> 15:49:27,820
this allows remote terminal access by
21779
15:49:30,000 --> 15:49:31,000
terminal we mean a window like this
21780
15:49:32,756 --> 15:49:33,756
where you've got command line access to
21781
15:49:35,820 --> 15:49:36,820
a remote computer server
21782
15:49:38,936 --> 15:49:39,936
or in this case I'm not sure what this
21783
15:49:41,220 --> 15:49:42,220
is actually it could be a Cisco device
21784
15:49:43,380 --> 15:49:44,380
of some sort
21785
15:49:45,596 --> 15:49:46,596
it encrypts communication between the
21786
15:49:47,640 --> 15:49:48,640
endpoint so most places now you can't
21787
15:49:51,540 --> 15:49:52,540
tell Nets across the network
21788
15:49:54,416 --> 15:49:55,416
you uh because it's all traffic is sent
21789
15:49:56,880 --> 15:49:57,880
in clear text you have to use secure
21790
15:49:58,616 --> 15:49:59,616
shell as part of the policy the network
21791
15:50:02,040 --> 15:50:03,040
policy
21792
15:50:03,720 --> 15:50:04,720
in order to use the Kershaw you have to
21793
15:50:06,840 --> 15:50:07,840
enable it on your server router or
21794
15:50:08,580 --> 15:50:09,580
switch it isn't usually enabled by
21795
15:50:10,980 --> 15:50:11,980
default
21796
15:50:12,296 --> 15:50:13,296
the client software you install on your
21797
15:50:15,296 --> 15:50:16,296
computer
21798
15:50:16,796 --> 15:50:17,796
the one I use mostly to get my remote
21799
15:50:20,456 --> 15:50:21,456
secure uh shell sessions is putty it's a
21800
15:50:24,776 --> 15:50:25,776
free download if you Google putty I
21801
15:50:27,000 --> 15:50:28,000
think it's pretty.org you got to you get
21802
15:50:29,160 --> 15:50:30,160
taken to
21803
15:50:31,256 --> 15:50:32,256
BNC I used this a while ago when I was
21804
15:50:33,480 --> 15:50:34,480
at holiday and needed to connect to my
21805
15:50:35,820 --> 15:50:36,820
work computer this is platform
21806
15:50:38,400 --> 15:50:39,400
independent it's a GUI based
21807
15:50:44,340 --> 15:50:45,340
which is pretty handy if you're not too
21808
15:50:46,080 --> 15:50:47,080
familiar with command line desktop
21809
15:50:48,060 --> 15:50:49,060
sharing it uses remote frame buffer to a
21810
15:50:51,720 --> 15:50:52,720
remote controller computer
21811
15:50:55,500 --> 15:50:56,500
all right you get the TCP Port basic uh
21812
15:50:58,320 --> 15:50:59,320
the port is um 5900 and then there's a
21813
15:51:00,956 --> 15:51:01,956
number the number will you check the
21814
15:51:02,580 --> 15:51:03,580
documentation but there's various
21815
15:51:03,900 --> 15:51:04,900
numbers you will be using depending on
21816
15:51:06,596 --> 15:51:07,596
what you're connecting to and how you
21817
15:51:09,240 --> 15:51:10,240
want to connect
21818
15:51:12,116 --> 15:51:13,116
now telnet is uh TCP protocol is used
21819
15:51:16,616 --> 15:51:17,616
for remote access I did mention SSH so
21820
15:51:19,200 --> 15:51:20,200
really tell net you'd use it at home if
21821
15:51:22,860 --> 15:51:23,860
you've got a rack or something you want
21822
15:51:24,840 --> 15:51:25,840
to troubleshoot you would never use this
21823
15:51:26,640 --> 15:51:27,640
in a corporate environment now you'd if
21824
15:51:29,160 --> 15:51:30,160
you went and did some configuration or
21825
15:51:31,740 --> 15:51:32,740
network installation for a company and
21826
15:51:33,416 --> 15:51:34,416
left town to open then I think you're
21827
15:51:35,456 --> 15:51:36,456
probably
21828
15:51:36,360 --> 15:51:37,360
um be in trouble legally because you've
21829
15:51:37,916 --> 15:51:38,916
left a big hole in their Network for
21830
15:51:39,840 --> 15:51:40,840
other people to connect
21831
15:51:41,756 --> 15:51:42,756
it requires client software just uh
21832
15:51:44,820 --> 15:51:45,820
something like putty used to have hyper
21833
15:51:46,560 --> 15:51:47,560
terminal with a Microsoft they stopped a
21834
15:51:50,580 --> 15:51:51,580
bundle in it with the software I think
21835
15:51:53,040 --> 15:51:54,040
um about four or five years ago
21836
15:51:55,200 --> 15:51:56,200
you could still enable it but you had to
21837
15:51:57,720 --> 15:51:58,720
go into the back end and um I think you
21838
15:52:00,240 --> 15:52:01,240
have to download some extra software but
21839
15:52:02,756 --> 15:52:03,756
um it didn't work it doesn't work too
21840
15:52:04,320 --> 15:52:05,320
well anyway uh uses TCP Port 23 make a
21841
15:52:08,580 --> 15:52:09,580
note of that all traffic isn't encrypted
21842
15:52:11,096 --> 15:52:12,096
not secure which is why we don't
21843
15:52:12,540 --> 15:52:13,540
recommend you use it
21844
15:52:15,660 --> 15:52:16,660
I've already mentioned this bundle
21845
15:52:17,456 --> 15:52:18,456
blocked
21846
15:52:19,400 --> 15:52:20,400
https management
21847
15:52:21,956 --> 15:52:22,956
this gives you the graphical uh access
21848
15:52:25,680 --> 15:52:26,680
method for a device when you first buy
21849
15:52:28,436 --> 15:52:29,436
for example a Cisco router and say you
21850
15:52:30,900 --> 15:52:31,900
don't know how to configure it you can
21851
15:52:33,060 --> 15:52:34,060
get the router you basically plug in an
21852
15:52:36,540 --> 15:52:37,540
ethernet cable here
21853
15:52:38,456 --> 15:52:39,456
you connect your
21854
15:52:40,680 --> 15:52:41,680
PC or laptop and in the documentation
21855
15:52:43,560 --> 15:52:44,560
that will come on a CD-ROM or you get a
21856
15:52:46,256 --> 15:52:47,256
little card it will basically say in
21857
15:52:49,380 --> 15:52:50,380
your browser window you put
21858
15:52:52,340 --> 15:52:53,340
HTTP possibly https and then you will
21859
15:52:56,936 --> 15:52:57,936
put a number so say for example your
21860
15:52:59,756 --> 15:53:00,756
home router will normally be something
21861
15:53:02,220 --> 15:53:03,220
like this 192.168.0.1
21862
15:53:06,060 --> 15:53:07,060
and then that will result that will
21863
15:53:08,040 --> 15:53:09,040
resolve it doesn't need to use DNS
21864
15:53:10,380 --> 15:53:11,380
because it's uh the using an IP address
21865
15:53:12,240 --> 15:53:13,240
it will resolve them to this management
21866
15:53:14,936 --> 15:53:15,936
window and on my route up on my home
21867
15:53:18,776 --> 15:53:19,776
router you've got a whole bunch of menus
21868
15:53:21,060 --> 15:53:22,060
here you can configure the firewall you
21869
15:53:24,596 --> 15:53:25,596
can reboot
21870
15:53:26,220 --> 15:53:27,220
you can check your DNS settings you can
21871
15:53:29,580 --> 15:53:30,580
permit or deny different devices if you
21872
15:53:31,860 --> 15:53:32,860
want your kids to access the internet or
21873
15:53:34,916 --> 15:53:35,916
you want to block them and you can you
21874
15:53:38,700 --> 15:53:39,700
can configure that
21875
15:53:40,916 --> 15:53:41,916
um
21876
15:53:42,180 --> 15:53:43,180
firmware etc etc anyway you get you get
21877
15:53:44,700 --> 15:53:45,700
the idea so this is your way of managing
21878
15:53:47,700 --> 15:53:48,700
your device it's a security issue if
21879
15:53:51,000 --> 15:53:52,000
enabled by default
21880
15:53:53,096 --> 15:53:54,096
I'm trying to remember now I think uh
21881
15:53:55,200 --> 15:53:56,200
Cisco devices is disabled by default but
21882
15:53:58,020 --> 15:53:59,020
sometimes you can have different
21883
15:53:59,340 --> 15:54:00,340
versions of iOS
21884
15:54:01,096 --> 15:54:02,096
where all enabled and then there's
21885
15:54:03,900 --> 15:54:04,900
something there's some change happens
21886
15:54:06,380 --> 15:54:07,380
and the command changes or the default
21887
15:54:09,956 --> 15:54:10,956
setting changes this is for routing
21888
15:54:12,180 --> 15:54:13,180
commands security commands how to switch
21889
15:54:15,720 --> 15:54:16,720
traffic packet switching and track and
21890
15:54:18,060 --> 15:54:19,060
frame switching
21891
15:54:19,560 --> 15:54:20,560
so um check what device you're on and if
21892
15:54:22,320 --> 15:54:23,320
it's enabled or disabled by default
21893
15:54:24,000 --> 15:54:25,000
generally you'll want it uh disabled
21894
15:54:27,296 --> 15:54:28,296
otherwise you've got to configure
21895
15:54:28,616 --> 15:54:29,616
Advanced usernames and passwords so put
21896
15:54:31,436 --> 15:54:32,436
the IP address into the browser bar
21897
15:54:33,956 --> 15:54:34,956
remote file access
21898
15:54:37,256 --> 15:54:38,256
FTP is used to upload and download large
21899
15:54:39,956 --> 15:54:40,956
files in securely
21900
15:54:42,180 --> 15:54:43,180
so this represents a problem
21901
15:54:46,456 --> 15:54:47,456
SFTP this is a protocol in its own right
21902
15:54:49,500 --> 15:54:50,500
so it's not as if you've got FTP and
21903
15:54:52,080 --> 15:54:53,080
added something to it this is its own
21904
15:54:54,540 --> 15:54:55,540
protocol
21905
15:54:55,740 --> 15:54:56,740
so just be careful it's encrypts a
21906
15:54:58,680 --> 15:54:59,680
secures an eclipse traffic it uses SSH
21907
15:55:01,200 --> 15:55:02,200
which is port 22.
21908
15:55:03,776 --> 15:55:04,776
so um don't think that it's an FTP with
21909
15:55:07,436 --> 15:55:08,436
some little extra bit on here
21910
15:55:10,200 --> 15:55:11,200
security bit security issue if enabled
21911
15:55:13,860 --> 15:55:14,860
by default this is um again I've done
21912
15:55:16,080 --> 15:55:17,080
that again sorry I've left it from the
21913
15:55:18,060 --> 15:55:19,060
last slide
21914
15:55:20,276 --> 15:55:21,276
your other file transfer method is
21915
15:55:22,756 --> 15:55:23,756
Trivial file transfer protocol which I
21916
15:55:25,320 --> 15:55:26,320
think we've mentioned earlier if you've
21917
15:55:26,880 --> 15:55:27,880
got a small file that you want to send
21918
15:55:30,296 --> 15:55:31,296
over your network again please don't use
21919
15:55:33,060 --> 15:55:34,060
this this is just what it's used for if
21920
15:55:35,276 --> 15:55:36,276
you've got a router and you want to back
21921
15:55:37,140 --> 15:55:38,140
up the configuration you've got a tiny
21922
15:55:39,480 --> 15:55:40,480
little file like about
21923
15:55:41,880 --> 15:55:42,880
a by uh eight bytes whatever or eight
21924
15:55:45,776 --> 15:55:46,776
kilobytes probably
21925
15:55:47,820 --> 15:55:48,820
um you'll you'll back it up here using
21926
15:55:50,220 --> 15:55:51,220
tftp
21927
15:55:52,380 --> 15:55:53,380
but again this file really is sensitive
21928
15:55:55,140 --> 15:55:56,140
because it's got IP addresses passwords
21929
15:55:57,116 --> 15:55:58,116
and heaven knows what so really using
21930
15:56:00,116 --> 15:56:01,116
tftp it shouldn't be done anymore if
21931
15:56:03,360 --> 15:56:04,360
you're at home you've got your little
21932
15:56:04,860 --> 15:56:05,860
home network and you want to have a play
21933
15:56:06,360 --> 15:56:07,360
with your software fine and if you're in
21934
15:56:09,360 --> 15:56:10,360
a corporate environment no I I think
21935
15:56:12,360 --> 15:56:13,360
it's a really bad idea
21936
15:56:14,400 --> 15:56:15,400
out of band access outer band basically
21937
15:56:17,580 --> 15:56:18,580
um
21938
15:56:18,480 --> 15:56:19,480
it's not within your normal ethernet
21939
15:56:21,000 --> 15:56:22,000
connection
21940
15:56:22,140 --> 15:56:23,140
so say you've got a router you've got a
21941
15:56:24,720 --> 15:56:25,720
fast ethernet port here and then you've
21942
15:56:27,000 --> 15:56:28,000
got your again your PC or whatever you
21943
15:56:30,540 --> 15:56:31,540
use to connect
21944
15:56:31,860 --> 15:56:32,860
so this will be your in-band
21945
15:56:36,416 --> 15:56:37,416
out of band would be something like a
21946
15:56:39,776 --> 15:56:40,776
modem connection so you've got your
21947
15:56:42,776 --> 15:56:43,776
router
21948
15:56:44,160 --> 15:56:45,160
and your
21949
15:56:47,096 --> 15:56:48,096
your you've got your telephone
21950
15:56:48,480 --> 15:56:49,480
connection here and then a modem
21951
15:56:53,756 --> 15:56:54,756
which is connected to your computer so
21952
15:56:56,580 --> 15:56:57,580
out of band
21953
15:56:58,380 --> 15:56:59,380
used for emergency access normally if
21954
15:57:01,020 --> 15:57:02,020
you're connecting out a band something
21955
15:57:03,240 --> 15:57:04,240
has gone wrong
21956
15:57:05,700 --> 15:57:06,700
now it looks like this is a modem here
21957
15:57:07,860 --> 15:57:08,860
and you can connect uh over the Internet
21958
15:57:10,740 --> 15:57:11,740
so you could connect to the modem and
21959
15:57:12,956 --> 15:57:13,956
then there's a a modem Port here
21960
15:57:15,180 --> 15:57:16,180
normally on Cisco devices it's got aux
21961
15:57:17,756 --> 15:57:18,756
written on it again check your
21962
15:57:19,560 --> 15:57:20,560
documentation because things change over
21963
15:57:21,596 --> 15:57:22,596
time
21964
15:57:22,616 --> 15:57:23,616
so attach your mode and support what you
21965
15:57:24,900 --> 15:57:25,900
would normally do is this wouldn't be
21966
15:57:26,756 --> 15:57:27,756
connected say you're in a corporate
21967
15:57:28,380 --> 15:57:29,380
environment so this is in your corporate
21968
15:57:30,660 --> 15:57:31,660
Network
21969
15:57:31,916 --> 15:57:32,916
and you've got a um
21970
15:57:36,840 --> 15:57:37,840
you've got your remote hands so this is
21971
15:57:39,720 --> 15:57:40,720
like your help desk team they're not
21972
15:57:42,116 --> 15:57:43,116
they're not that technical say they're
21973
15:57:44,040 --> 15:57:45,040
level one but you've got people who if
21974
15:57:46,500 --> 15:57:47,500
you send them in the instructions to go
21975
15:57:49,080 --> 15:57:50,080
to rack
21976
15:57:51,000 --> 15:57:52,000
one and
21977
15:57:53,520 --> 15:57:54,520
um find
21978
15:57:55,080 --> 15:57:56,080
say Row three or whatever and ask them
21979
15:57:58,320 --> 15:57:59,320
to plug in the cable and you'll have the
21980
15:57:59,700 --> 15:58:00,700
cable sitting there but not plugged in
21981
15:58:01,200 --> 15:58:02,200
you'll do the fix bring the router back
21982
15:58:04,080 --> 15:58:05,080
up so all the other ports are working
21983
15:58:05,640 --> 15:58:06,640
and then they will disconnect that again
21984
15:58:08,296 --> 15:58:09,296
and you'll normally have obviously a
21985
15:58:10,616 --> 15:58:11,616
ticketing system of some sort where
21986
15:58:12,596 --> 15:58:13,596
you'll say plug it in and then confirm
21987
15:58:15,240 --> 15:58:16,240
that they have unplugged it because it's
21988
15:58:16,560 --> 15:58:17,560
a security
21989
15:58:18,296 --> 15:58:19,296
um issue so just be careful
21990
15:58:21,596 --> 15:58:22,596
so I've mentioned remote hands um you
21991
15:58:23,936 --> 15:58:24,936
can use a console oh you can use a
21992
15:58:25,680 --> 15:58:26,680
console router for multiple out of band
21993
15:58:28,140 --> 15:58:29,140
devices so say you've got this is
21994
15:58:30,660 --> 15:58:31,660
normally we used to do this when we were
21995
15:58:32,700 --> 15:58:33,700
practicing for Cisco exams you out of a
21996
15:58:35,640 --> 15:58:36,640
rack of all of these different routers
21997
15:58:39,116 --> 15:58:40,116
say router 1 router 2 router 3 switch
21998
15:58:42,900 --> 15:58:43,900
one
21999
15:58:44,700 --> 15:58:45,700
switch to and you haven't got ethernet
22000
15:58:47,400 --> 15:58:48,400
access for whatever reason so what you
22001
15:58:50,220 --> 15:58:51,220
do is you'd have this uh a console
22002
15:58:53,756 --> 15:58:54,756
router I can't fit it all in a console
22003
15:58:55,916 --> 15:58:56,916
router
22004
15:58:57,720 --> 15:58:58,720
which basically connects to the console
22005
15:58:59,640 --> 15:59:00,640
ports of all these devices now console
22006
15:59:02,340 --> 15:59:03,340
connections don't work over the Internet
22007
15:59:04,256 --> 15:59:05,256
it's an out of band thing so what you
22008
15:59:07,256 --> 15:59:08,256
would do would would tell net to this
22009
15:59:09,240 --> 15:59:10,240
device here
22010
15:59:10,380 --> 15:59:11,380
and then through this router here it
22011
15:59:12,660 --> 15:59:13,660
would have the telnet the software the
22012
15:59:15,416 --> 15:59:16,416
client software that you could configure
22013
15:59:18,000 --> 15:59:19,000
all of these devices through a command
22014
15:59:19,616 --> 15:59:20,616
line
22015
15:59:20,700 --> 15:59:21,700
and um really handy way of connecting to
22016
15:59:23,220 --> 15:59:24,220
remote racks but you could have this for
22017
15:59:24,956 --> 15:59:25,956
your corporate Network
22018
15:59:27,416 --> 15:59:28,416
this is an example of one this is a the
22019
15:59:30,296 --> 15:59:31,296
the models of routers for Cisco are 25
22020
15:59:32,936 --> 15:59:33,936
11 and 25
22021
15:59:35,596 --> 15:59:36,596
21. now you can see how old this is this
22022
15:59:38,456 --> 15:59:39,456
is your ethernet connection look at that
22023
15:59:40,256 --> 15:59:41,256
the aui
22024
15:59:41,936 --> 15:59:42,936
so what you do we've all we've talked
22025
15:59:43,860 --> 15:59:44,860
about transceivers already you think but
22026
15:59:45,956 --> 15:59:46,956
you'd have this transceiver that's got a
22027
15:59:48,296 --> 15:59:49,296
an ethernet port in here so you could
22028
15:59:49,980 --> 15:59:50,980
connect an Ethernet cable to another
22029
15:59:51,956 --> 15:59:52,956
device which then lets you get in at 10
22030
15:59:55,500 --> 15:59:56,500
Meg
22031
15:59:57,840 --> 15:59:58,840
um so pretty slow uh old-fashioned
22032
16:00:00,540 --> 16:00:01,540
serial connection there I said db60
22033
16:00:04,796 --> 16:00:05,796
and then your console port for console
22034
16:00:06,840 --> 16:00:07,840
connections this is your modem I've
22035
16:00:08,936 --> 16:00:09,936
talked about
22036
16:00:10,616 --> 16:00:11,616
your uh for your outer band access
22037
16:00:13,916 --> 16:00:14,916
and what this is is a bunch of console
22038
16:00:16,740 --> 16:00:17,740
connections so you can see one here
22039
16:00:18,776 --> 16:00:19,776
they've all got numbers on
22040
16:00:20,580 --> 16:00:21,580
and it's numbered one to eight here and
22041
16:00:23,640 --> 16:00:24,640
then if you plugged in the second one if
22042
16:00:25,200 --> 16:00:26,200
you needed um up to 16 devices then
22043
16:00:28,256 --> 16:00:29,256
these numbers I won't tell you how to
22044
16:00:29,936 --> 16:00:30,936
configure it I've got a video on YouTube
22045
16:00:31,380 --> 16:00:32,380
if you want to look that up under my
22046
16:00:33,776 --> 16:00:34,776
name Paul Browning
22047
16:00:35,880 --> 16:00:36,880
and you could connect these from a load
22048
16:00:37,680 --> 16:00:38,680
of other devices so really what you were
22049
16:00:39,596 --> 16:00:40,596
doing is connecting to this device
22050
16:00:41,040 --> 16:00:42,040
whatever this modeler switch is
22051
16:00:43,916 --> 16:00:44,916
but you're doing it you're telnetting or
22052
16:00:46,380 --> 16:00:47,380
get all rem or connected through a modem
22053
16:00:49,560 --> 16:00:50,560
connection to this device and then from
22054
16:00:52,796 --> 16:00:53,796
here you're choosing whatever console
22055
16:00:54,720 --> 16:00:55,720
line is free so for example one and then
22056
16:00:57,776 --> 16:00:58,776
you can actually configure this device
22057
16:01:00,000 --> 16:01:01,000
so it's a slightly longer way of doing
22058
16:01:01,796 --> 16:01:02,796
things but
22059
16:01:03,660 --> 16:01:04,660
um that saves you having to configure
22060
16:01:05,700 --> 16:01:06,700
tile net connections
22061
16:01:08,160 --> 16:01:09,160
to 16 different devices so pretty handy
22062
16:01:12,000 --> 16:01:13,000
so we covered a load of stuff RDP SSH
22063
16:01:14,756 --> 16:01:15,756
VNC telnet
22064
16:01:16,936 --> 16:01:17,936
https for your GUI uh
22065
16:01:20,520 --> 16:01:21,520
access here file access and then outer
22066
16:01:23,756 --> 16:01:24,756
band so it covered a lot of stuff so
22067
16:01:25,916 --> 16:01:26,916
thanks for listening I'll see you on the
22068
16:01:27,360 --> 16:01:28,360
next presentation
22069
16:01:31,260 --> 16:01:32,260
[Music]
22070
16:01:51,320 --> 16:01:52,320
remote access
22071
16:01:53,480 --> 16:01:54,480
vpns and their protocols
22072
16:01:57,060 --> 16:01:58,060
in the last two modules we discussed
22073
16:01:59,400 --> 16:02:00,400
remote access and remote networking both
22074
16:02:03,776 --> 16:02:04,776
are basically around the same concept
22075
16:02:05,580 --> 16:02:06,580
remote networking meaning that I can
22076
16:02:07,796 --> 16:02:08,796
create a network that exists in two very
22077
16:02:10,380 --> 16:02:11,380
different geographical locations and
22078
16:02:12,360 --> 16:02:13,360
remote access meaning that I can access
22079
16:02:14,936 --> 16:02:15,936
a computer or a network from one
22080
16:02:18,000 --> 16:02:19,000
geographic location to another so
22081
16:02:19,796 --> 16:02:20,796
they're both basically the same thing
22082
16:02:21,060 --> 16:02:22,060
but how we accomplish this in a secure
22083
16:02:23,640 --> 16:02:24,640
fashion is what we're going to talk
22084
16:02:25,320 --> 16:02:26,320
about in this module and that revolves
22085
16:02:27,596 --> 16:02:28,596
around this term VPN a VPN I've talked
22086
16:02:30,776 --> 16:02:31,776
about a bit in the future in the past
22087
16:02:32,400 --> 16:02:33,400
rather and it stands for virtual
22088
16:02:36,060 --> 16:02:37,060
private
22089
16:02:38,700 --> 16:02:39,700
Network and as that term implies and
22090
16:02:41,096 --> 16:02:42,096
like we've discussed it creates a tunnel
22091
16:02:44,756 --> 16:02:45,756
through the net the internet the wide
22092
16:02:48,000 --> 16:02:49,000
area network in which we can securely
22093
16:02:50,936 --> 16:02:51,936
send uh data between two locations and
22094
16:02:55,140 --> 16:02:56,140
why the tunnel well that's what keeps it
22095
16:02:56,880 --> 16:02:57,880
secure and private from everyone else on
22096
16:02:58,860 --> 16:02:59,860
the internet and this is how we've been
22097
16:03:00,720 --> 16:03:01,720
able to allow remote networking to
22098
16:03:02,756 --> 16:03:03,756
become so ubiquitous in our world
22099
16:03:04,560 --> 16:03:05,560
because I no longer have to have a
22100
16:03:06,900 --> 16:03:07,900
direct T3 or T1 line between my office
22101
16:03:09,180 --> 16:03:10,180
and my home instead I can use the
22102
16:03:11,756 --> 16:03:12,756
internet which is fairly ubiquitous
22103
16:03:13,320 --> 16:03:14,320
these days and create a virtual private
22104
16:03:16,140 --> 16:03:17,140
Network again virtual being the key word
22105
16:03:18,416 --> 16:03:19,416
there because it's not actually a
22106
16:03:19,740 --> 16:03:20,740
private Network it's a virtual private
22107
16:03:21,116 --> 16:03:22,116
Network because of this sort of
22108
16:03:22,616 --> 16:03:23,616
tunneling concept that we're going to
22109
16:03:24,060 --> 16:03:25,060
talk about
22110
16:03:25,080 --> 16:03:26,080
so what we're going to talk about in
22111
16:03:26,640 --> 16:03:27,640
this module is first to Define virtual
22112
16:03:29,096 --> 16:03:30,096
private networks a bit more and then
22113
16:03:30,956 --> 16:03:31,956
talk about the different scene of VPN
22114
16:03:32,456 --> 16:03:33,456
client and VPN server we've seen the
22115
16:03:34,680 --> 16:03:35,680
terms client and server in the past so
22116
16:03:36,360 --> 16:03:37,360
these shouldn't be too new for you
22117
16:03:38,820 --> 16:03:39,820
then I want to talk about the VPN
22118
16:03:41,456 --> 16:03:42,456
protocols there are two specific ones
22119
16:03:43,616 --> 16:03:44,616
that you need to know about for the exam
22120
16:03:45,720 --> 16:03:46,720
one is called pptp and the other is l2tp
22121
16:03:50,580 --> 16:03:51,580
notice the T in there for tunneling
22122
16:03:54,240 --> 16:03:55,240
so we're going to discuss both of those
22123
16:03:55,796 --> 16:03:56,796
and how they all work all right so first
22124
16:03:59,096 --> 16:04:00,096
virtual private networks a virtual
22125
16:04:01,380 --> 16:04:02,380
private Network or a VPN is is nowadays
22126
16:04:03,840 --> 16:04:04,840
an essential part of networking it's
22127
16:04:06,060 --> 16:04:07,060
basically used anytime a network is
22128
16:04:08,340 --> 16:04:09,340
extended Beyond a lan or local area
22129
16:04:11,040 --> 16:04:12,040
network so it establishes a remote
22130
16:04:13,500 --> 16:04:14,500
connection through a public network such
22131
16:04:16,436 --> 16:04:17,436
as the internet in order to extend the
22132
16:04:18,956 --> 16:04:19,956
Lan and I'll show you a graphic of this
22133
16:04:20,520 --> 16:04:21,520
in just a second once the extension is
22134
16:04:23,220 --> 16:04:24,220
made a dedicated point-to-point link
22135
16:04:27,660 --> 16:04:28,660
point
22136
16:04:31,380 --> 16:04:32,380
to point link which you might also have
22137
16:04:33,900 --> 16:04:34,900
seen P2P a dedicated point-to-point link
22138
16:04:37,380 --> 16:04:38,380
is created between two points using the
22139
16:04:39,776 --> 16:04:40,776
same IP network meaning that even though
22140
16:04:42,596 --> 16:04:43,596
we are on two very different IP networks
22141
16:04:45,116 --> 16:04:46,116
I might not be on my land you might be
22142
16:04:47,096 --> 16:04:48,096
on yours we can create a virtual
22143
16:04:49,560 --> 16:04:50,560
point-to-point connection between the
22144
16:04:51,660 --> 16:04:52,660
two using tunneling that makes it as
22145
16:04:53,936 --> 16:04:54,936
though we are on the same point-to-point
22146
16:04:55,916 --> 16:04:56,916
network the same IP network and I'll
22147
16:04:58,320 --> 16:04:59,320
show you that in just a second now the
22148
16:05:00,956 --> 16:05:01,956
extension of the Lan are sometimes the
22149
16:05:02,756 --> 16:05:03,756
linking of two lands
22150
16:05:05,456 --> 16:05:06,456
creates a new wide area network so you
22151
16:05:08,456 --> 16:05:09,456
could say that anytime a VPN is
22152
16:05:10,380 --> 16:05:11,380
established
22153
16:05:15,900 --> 16:05:16,900
and a new land sort of added on a new
22154
16:05:18,720 --> 16:05:19,720
Wan is created don't worry too much
22155
16:05:21,060 --> 16:05:22,060
about that concept but the idea again is
22156
16:05:23,520 --> 16:05:24,520
if I have the office slam
22157
16:05:27,116 --> 16:05:28,116
and let's say either another office
22158
16:05:30,296 --> 16:05:31,296
and then perhaps a remote user
22159
16:05:35,240 --> 16:05:36,240
all connecting through VPN
22160
16:05:38,580 --> 16:05:39,580
over the internet
22161
16:05:41,220 --> 16:05:42,220
I now have created an effect
22162
16:05:46,256 --> 16:05:47,256
a wide area network out of three very
22163
16:05:49,020 --> 16:05:50,020
distinct local area networks but I
22164
16:05:51,540 --> 16:05:52,540
haven't used any different
22165
16:05:52,616 --> 16:05:53,616
infrastructure than something that was
22166
16:05:54,360 --> 16:05:55,360
already there
22167
16:05:55,796 --> 16:05:56,796
now vpns are actually a type of remote
22168
16:05:58,560 --> 16:05:59,560
access probably the most popular one
22169
16:06:00,956 --> 16:06:01,956
they share similarities to all the
22170
16:06:02,936 --> 16:06:03,936
different remote access for instance
22171
16:06:05,820 --> 16:06:06,820
you might think of dialing via modem but
22172
16:06:09,000 --> 16:06:10,000
vpns are inexpensive way to extend your
22173
16:06:11,936 --> 16:06:12,936
network because it uses the internet so
22174
16:06:13,680 --> 16:06:14,680
you don't need to purchase a leased line
22175
16:06:15,480 --> 16:06:16,480
service now remote users just Connect
22176
16:06:17,936 --> 16:06:18,936
using the VPN to their remote office
22177
16:06:22,320 --> 16:06:23,320
through the internet
22178
16:06:24,116 --> 16:06:25,116
and so that's really the key here is it
22179
16:06:26,820 --> 16:06:27,820
uses the internet as its platform
22180
16:06:30,900 --> 16:06:31,900
so
22181
16:06:32,040 --> 16:06:33,040
this is what access through a VPN might
22182
16:06:34,916 --> 16:06:35,916
look like the remote users
22183
16:06:38,520 --> 16:06:39,520
connect let's say from home through the
22184
16:06:41,340 --> 16:06:42,340
internet and then there is a
22185
16:06:44,956 --> 16:06:45,956
authentication server that verifies that
22186
16:06:48,116 --> 16:06:49,116
this user is allowed on the network once
22187
16:06:50,340 --> 16:06:51,340
you pass through that it puts you into a
22188
16:06:52,320 --> 16:06:53,320
switch which then makes it as though
22189
16:06:55,080 --> 16:06:56,080
both of these computers
22190
16:06:57,840 --> 16:06:58,840
are on this LAN
22191
16:07:00,900 --> 16:07:01,900
so in effect I've created a new Wan
22192
16:07:05,220 --> 16:07:06,220
without having to lay down any extra
22193
16:07:07,740 --> 16:07:08,740
line because I'm again using the
22194
16:07:10,560 --> 16:07:11,560
internet now
22195
16:07:12,296 --> 16:07:13,296
say that this was an office building
22196
16:07:15,840 --> 16:07:16,840
it could have an office building here
22197
16:07:17,480 --> 16:07:18,480
perhaps another one and these can be any
22198
16:07:20,400 --> 16:07:21,400
place in the world
22199
16:07:23,756 --> 16:07:24,756
and because I'm using tunneling through
22200
16:07:26,700 --> 16:07:27,700
the virtual private Network
22201
16:07:30,900 --> 16:07:31,900
I create an effect a tunnel which allows
22202
16:07:34,616 --> 16:07:35,616
all of these to each create a
22203
16:07:36,660 --> 16:07:37,660
point-to-point connection
22204
16:07:38,936 --> 16:07:39,936
between themselves and this
22205
16:07:41,340 --> 16:07:42,340
authentication server that then
22206
16:07:43,436 --> 16:07:44,436
basically puts them
22207
16:07:45,540 --> 16:07:46,540
onto this Lan so any one of these
22208
16:07:48,360 --> 16:07:49,360
offices is now part of
22209
16:07:50,820 --> 16:07:51,820
the land and in effect then making a
22210
16:07:53,276 --> 16:07:54,276
brand new Wan or wide area network
22211
16:07:58,200 --> 16:07:59,200
now there are a lot of things we need in
22212
16:07:59,700 --> 16:08:00,700
order to set up a VPN connection and
22213
16:08:02,456 --> 16:08:03,456
some of them are
22214
16:08:04,080 --> 16:08:05,080
more important than others but I'm just
22215
16:08:05,936 --> 16:08:06,936
going to key in on the the main things
22216
16:08:08,640 --> 16:08:09,640
we need
22217
16:08:10,140 --> 16:08:11,140
first we need a VPN client now the
22218
16:08:13,616 --> 16:08:14,616
client is the remote access user without
22219
16:08:16,320 --> 16:08:17,320
this user there's no point in setting up
22220
16:08:18,296 --> 16:08:19,296
a VPN so why bother if no one needs to
22221
16:08:20,580 --> 16:08:21,580
connect they are one of the most
22222
16:08:23,220 --> 16:08:24,220
important clients or the ways that we
22223
16:08:25,820 --> 16:08:26,820
components rather and what's interesting
22224
16:08:28,320 --> 16:08:29,320
about a VPN client is it can either be
22225
16:08:30,416 --> 16:08:31,416
software
22226
16:08:33,000 --> 16:08:34,000
or Hardware
22227
16:08:35,820 --> 16:08:36,820
if it's software then it's
22228
16:08:40,020 --> 16:08:41,020
built into the operating system
22229
16:08:41,700 --> 16:08:42,700
generally or into the networking package
22230
16:08:43,500 --> 16:08:44,500
of the operating system if it's Hardware
22231
16:08:46,916 --> 16:08:47,916
it's generally either built
22232
16:08:49,740 --> 16:08:50,740
into the router
22233
16:08:52,740 --> 16:08:53,740
or it's a separate device
22234
16:08:57,416 --> 16:08:58,416
which is generally called
22235
16:08:59,936 --> 16:09:00,936
VPN concentrator
22236
16:09:03,956 --> 16:09:04,956
now the benefit is
22237
16:09:05,936 --> 16:09:06,936
if I have for instance two offices
22238
16:09:10,916 --> 16:09:11,916
we'll call them office one and office
22239
16:09:12,660 --> 16:09:13,660
two and they are located in different
22240
16:09:14,580 --> 16:09:15,580
parts of the world
22241
16:09:15,900 --> 16:09:16,900
but they both connect to the internet
22242
16:09:18,596 --> 16:09:19,596
then I don't want each so let's say each
22243
16:09:21,900 --> 16:09:22,900
of these offices has we'll put four
22244
16:09:24,060 --> 16:09:25,060
users for now but let's say these four
22245
16:09:26,160 --> 16:09:27,160
really represent 4 000 users I don't
22246
16:09:29,276 --> 16:09:30,276
want each one of these people to have to
22247
16:09:31,980 --> 16:09:32,980
set up on their computers a piece of
22248
16:09:34,740 --> 16:09:35,740
software that's going to allow them to
22249
16:09:36,416 --> 16:09:37,416
connect
22250
16:09:38,456 --> 16:09:39,456
through this tunnel so instead what I've
22251
16:09:40,980 --> 16:09:41,980
done
22252
16:09:42,416 --> 16:09:43,416
is I do something on the network side of
22253
16:09:45,416 --> 16:09:46,416
the office for instance in the router or
22254
16:09:47,580 --> 16:09:48,580
with a device that automatically creates
22255
16:09:51,000 --> 16:09:52,000
this tunnel between the two offices
22256
16:09:53,936 --> 16:09:54,936
and then these members don't have to do
22257
16:09:56,756 --> 16:09:57,756
anything now if I am a lone user at home
22258
16:10:04,500 --> 16:10:05,500
then I'm probably it's going to be
22259
16:10:05,820 --> 16:10:06,820
easier for me instead of buying a device
22260
16:10:07,796 --> 16:10:08,796
that's going to allow a network to
22261
16:10:09,480 --> 16:10:10,480
always set up to just plug in through my
22262
16:10:12,116 --> 16:10:13,116
computer and put it into the software
22263
16:10:14,340 --> 16:10:15,340
whenever I need
22264
16:10:15,720 --> 16:10:16,720
and if I go into Windows 7 real quickly
22265
16:10:18,596 --> 16:10:19,596
go over here into
22266
16:10:21,596 --> 16:10:22,596
our Network and Sharing
22267
16:10:24,060 --> 16:10:25,060
and say we were going to set up a new
22268
16:10:26,580 --> 16:10:27,580
network you can see right here it says
22269
16:10:28,436 --> 16:10:29,436
set up a VPN connection and if we go and
22270
16:10:30,900 --> 16:10:31,900
do this you can actually connect to a
22271
16:10:32,880 --> 16:10:33,880
workplace now connecting to a workplace
22272
16:10:34,436 --> 16:10:35,436
what they really mean is setting up a
22273
16:10:35,936 --> 16:10:36,936
VPN connection so I'm going to click
22274
16:10:37,796 --> 16:10:38,796
next
22275
16:10:38,756 --> 16:10:39,756
now you can see I can either dial
22276
16:10:40,080 --> 16:10:41,080
directly which is something that we
22277
16:10:41,640 --> 16:10:42,640
might have done years ago or one the one
22278
16:10:43,200 --> 16:10:44,200
we're going to use more likely now is
22279
16:10:45,116 --> 16:10:46,116
the through the internet connection
22280
16:10:46,616 --> 16:10:47,616
again creating that VPN
22281
16:10:48,660 --> 16:10:49,660
we could call this whatever now one
22282
16:10:50,520 --> 16:10:51,520
thing we would need here is the server
22283
16:10:52,616 --> 16:10:53,616
address we'll talk about that but why in
22284
16:10:55,500 --> 16:10:56,500
just a second but we are the client and
22285
16:10:56,936 --> 16:10:57,936
we need to connect to a server so this
22286
16:10:58,796 --> 16:10:59,796
is where for instance that
22287
16:11:02,756 --> 16:11:03,756
server address is going to go now you
22288
16:11:04,740 --> 16:11:05,740
know this IP address wouldn't work
22289
16:11:06,416 --> 16:11:07,416
because this is a private IP address but
22290
16:11:08,756 --> 16:11:09,756
we're just using this for the time being
22291
16:11:10,796 --> 16:11:11,796
right here you can use sharing Etc but
22292
16:11:14,220 --> 16:11:15,220
for right now let's just go ahead and
22293
16:11:15,296 --> 16:11:16,296
click next
22294
16:11:17,040 --> 16:11:18,040
let's say our username
22295
16:11:19,200 --> 16:11:20,200
so let's say user and then we have a
22296
16:11:21,720 --> 16:11:22,720
password I'm just going to do password
22297
16:11:23,520 --> 16:11:24,520
we can have it remember the password or
22298
16:11:25,500 --> 16:11:26,500
not you might have a domain if you're
22299
16:11:26,936 --> 16:11:27,936
connecting to a Windows computer and
22300
16:11:28,680 --> 16:11:29,680
then you click connect
22301
16:11:30,416 --> 16:11:31,416
the next thing I need obviously is
22302
16:11:32,160 --> 16:11:33,160
something for the VPN client to connect
22303
16:11:34,436 --> 16:11:35,436
to and this is the VPN server the VPN
22304
16:11:37,740 --> 16:11:38,740
server not only allows the connection to
22305
16:11:40,140 --> 16:11:41,140
take place but is also going to
22306
16:11:43,320 --> 16:11:44,320
authenticate
22307
16:11:46,616 --> 16:11:47,616
the client and allow them to connect
22308
16:11:51,416 --> 16:11:52,416
now this might be done through again
22309
16:11:53,340 --> 16:11:54,340
some sort of device like this VPN
22310
16:11:55,436 --> 16:11:56,436
concentrator I've mentioned or through a
22311
16:11:58,080 --> 16:11:59,080
separate server that has software hooked
22312
16:12:00,060 --> 16:12:01,060
up on it either way I need some sort of
22313
16:12:03,180 --> 16:12:04,180
device
22314
16:12:05,400 --> 16:12:06,400
that allows
22315
16:12:08,400 --> 16:12:09,400
outside
22316
16:12:11,276 --> 16:12:12,276
clients
22317
16:12:12,840 --> 16:12:13,840
to connect in to the network basically
22318
16:12:15,240 --> 16:12:16,240
to give them permission act as sort of a
22319
16:12:17,220 --> 16:12:18,220
a controller or or a Gates person
22320
16:12:20,240 --> 16:12:21,240
uh there are different ways of setting
22321
16:12:22,740 --> 16:12:23,740
this up and you remember I mentioned
22322
16:12:24,240 --> 16:12:25,240
something called an Ras remote access
22323
16:12:26,700 --> 16:12:27,700
server and the specific one we mentioned
22324
16:12:29,340 --> 16:12:30,340
previously was a radius server
22325
16:12:33,180 --> 16:12:34,180
which was a remote access dial-in uh
22326
16:12:36,900 --> 16:12:37,900
server and
22327
16:12:39,240 --> 16:12:40,240
although this was for dial up it still
22328
16:12:41,720 --> 16:12:42,720
does the same thing which is it allows
22329
16:12:44,220 --> 16:12:45,220
someone to remotely access the local
22330
16:12:47,520 --> 16:12:48,520
network so we have some sort of Ras and
22331
16:12:50,580 --> 16:12:51,580
again an Ras stands for let me just
22332
16:12:53,160 --> 16:12:54,160
write that out remote
22333
16:12:55,980 --> 16:12:56,980
access
22334
16:12:58,140 --> 16:12:59,140
server
22335
16:13:01,796 --> 16:13:02,796
now the access method is also pretty
22336
16:13:04,740 --> 16:13:05,740
important without a connection there's
22337
16:13:07,500 --> 16:13:08,500
no way for a user to get onto the
22338
16:13:09,000 --> 16:13:10,000
network so most of the time this
22339
16:13:10,796 --> 16:13:11,796
connection comes from the internet but
22340
16:13:12,480 --> 16:13:13,480
it's not uncommon for a VPN
22341
16:13:14,160 --> 16:13:15,160
implementation to actually come through
22342
16:13:15,660 --> 16:13:16,660
a private intranet as well so we have
22343
16:13:18,900 --> 16:13:19,900
the internet which is the public version
22344
16:13:21,116 --> 16:13:22,116
but there's also something called the
22345
16:13:23,116 --> 16:13:24,116
intranet if you recall the internet is
22346
16:13:25,500 --> 16:13:26,500
like a private internet and sometimes we
22347
16:13:28,796 --> 16:13:29,796
might actually have a private leased
22348
16:13:31,080 --> 16:13:32,080
line or we have several different sub
22349
16:13:33,480 --> 16:13:34,480
networks within a larger Network and so
22350
16:13:35,936 --> 16:13:36,936
it's important to know where your people
22351
16:13:37,680 --> 16:13:38,680
are connecting from most the time you're
22352
16:13:39,840 --> 16:13:40,840
not going to see the intranet it's all
22353
16:13:41,456 --> 16:13:42,456
going to be through the internet and
22354
16:13:43,140 --> 16:13:44,140
sometimes you'll also have people
22355
16:13:43,980 --> 16:13:44,980
dialing up so it's all important to know
22356
16:13:46,140 --> 16:13:47,140
even though internet is the most popular
22357
16:13:48,060 --> 16:13:49,060
sometimes we're going to be doing it
22358
16:13:49,380 --> 16:13:50,380
internally through an intranet and
22359
16:13:51,540 --> 16:13:52,540
finally there are two protocols that we
22360
16:13:53,756 --> 16:13:54,756
need to know about and the generally are
22361
16:13:55,256 --> 16:13:56,256
set up on the server side and the client
22362
16:13:57,360 --> 16:13:58,360
needs to be configured to set up through
22363
16:13:59,040 --> 16:14:00,040
the first is PP TP which we're going to
22364
16:14:03,416 --> 16:14:04,416
talk about in a minute and this stands
22365
16:14:05,040 --> 16:14:06,040
for
22366
16:14:06,240 --> 16:14:07,240
point
22367
16:14:07,740 --> 16:14:08,740
two point
22368
16:14:10,380 --> 16:14:11,380
tunneling
22369
16:14:13,200 --> 16:14:14,200
protocol
22370
16:14:15,296 --> 16:14:16,296
the other is
22371
16:14:17,956 --> 16:14:18,956
l2tp which stands for Layer Two
22372
16:14:22,916 --> 16:14:23,916
tunneling
22373
16:14:24,900 --> 16:14:25,900
protocol
22374
16:14:26,220 --> 16:14:27,220
and if you remember talking about the OS
22375
16:14:28,200 --> 16:14:29,200
and I and the tcpip models that's what
22376
16:14:31,020 --> 16:14:32,020
that layer 2 refers to
22377
16:14:33,060 --> 16:14:34,060
so let's talk a little bit more about
22378
16:14:34,860 --> 16:14:35,860
these protocols the VPN Protocols are
22379
16:14:37,916 --> 16:14:38,916
really important to the security and
22380
16:14:39,720 --> 16:14:40,720
efficiency of VPN so the protocols
22381
16:14:42,616 --> 16:14:43,616
manage establish and secure the data
22382
16:14:46,796 --> 16:14:47,796
that's going on through that VPN
22383
16:14:48,720 --> 16:14:49,720
connection so pptp and l2tp are the two
22384
16:14:53,580 --> 16:14:54,580
most common protocols that are out there
22385
16:14:56,276 --> 16:14:57,276
they function pretty differently but
22386
16:14:58,020 --> 16:14:59,020
their jobs are fairly similar they
22387
16:15:00,480 --> 16:15:01,480
enable
22388
16:15:03,360 --> 16:15:04,360
encryption
22389
16:15:06,116 --> 16:15:07,116
which means the data isn't sent in its
22390
16:15:09,000 --> 16:15:10,000
sort of plain text format it's sent in a
22391
16:15:11,220 --> 16:15:12,220
way that if you were just to see it it
22392
16:15:12,840 --> 16:15:13,840
would look like it's all gobbley
22393
16:15:14,640 --> 16:15:15,640
and so what happens it's set on one end
22394
16:15:16,740 --> 16:15:17,740
in a code and then received and decode
22395
16:15:18,360 --> 16:15:19,360
on the other end and it also provides
22396
16:15:20,160 --> 16:15:21,160
authentication so only those who are
22397
16:15:22,680 --> 16:15:23,680
allowed on the network actually get on
22398
16:15:25,380 --> 16:15:26,380
the authentication it also establishes
22399
16:15:28,616 --> 16:15:29,616
the identities of the people in the
22400
16:15:30,000 --> 16:15:31,000
network so we can audit them it's a way
22401
16:15:32,160 --> 16:15:33,160
for the clients and the servers to be on
22402
16:15:34,380 --> 16:15:35,380
the same page about who is on the
22403
16:15:36,180 --> 16:15:37,180
network
22404
16:15:37,020 --> 16:15:38,020
and like I mentioned encryption is
22405
16:15:39,596 --> 16:15:40,596
really for the data protection so
22406
16:15:41,880 --> 16:15:42,880
because we're going through the internet
22407
16:15:44,400 --> 16:15:45,400
which is public this is really at risk
22408
16:15:46,796 --> 16:15:47,796
for attackers and so the encryption
22409
16:15:48,596 --> 16:15:49,596
protects that data that's traveling
22410
16:15:50,640 --> 16:15:51,640
through the network and prevents these
22411
16:15:51,956 --> 16:15:52,956
issues from happening generally speaking
22412
16:15:54,360 --> 16:15:55,360
we're going to prefer l2tp over pptp
22413
16:15:58,200 --> 16:15:59,200
just because it's a more advanced
22414
16:16:00,296 --> 16:16:01,296
protocol and uses a different form of
22415
16:16:01,980 --> 16:16:02,980
encryption
22416
16:16:03,000 --> 16:16:04,000
I think in fact
22417
16:16:05,276 --> 16:16:06,276
Windows 7 and Vista only allows lttdp
22418
16:16:08,880 --> 16:16:09,880
now it doesn't even allow pptp as we
22419
16:16:11,096 --> 16:16:12,096
just saw when we looked into windows
22420
16:16:14,276 --> 16:16:15,276
all right so just to recap what we just
22421
16:16:16,796 --> 16:16:17,796
talked about first we mentioned virtual
22422
16:16:18,776 --> 16:16:19,776
private networks which you'll never see
22423
16:16:20,400 --> 16:16:21,400
referred to as virtual private networks
22424
16:16:21,840 --> 16:16:22,840
you'll see them referred to as vpns and
22425
16:16:25,380 --> 16:16:26,380
those basically create a tunnel
22426
16:16:29,276 --> 16:16:30,276
through generally the internet sometimes
22427
16:16:33,240 --> 16:16:34,240
the Intranet
22428
16:16:35,756 --> 16:16:36,756
to connect
22429
16:16:38,400 --> 16:16:39,400
lands together and in effect then
22430
16:16:41,456 --> 16:16:42,456
creating one large Wan now this can be
22431
16:16:44,640 --> 16:16:45,640
done between office and office or say a
22432
16:16:47,400 --> 16:16:48,400
home user in an office and either way
22433
16:16:49,916 --> 16:16:50,916
you have a VPN client which would be the
22434
16:16:52,860 --> 16:16:53,860
one connecting to the server and
22435
16:16:55,680 --> 16:16:56,680
remember we have either software
22436
16:16:59,880 --> 16:17:00,880
or Hardware we looked at the software
22437
16:17:02,700 --> 16:17:03,700
that was built into windows we also have
22438
16:17:05,096 --> 16:17:06,096
Hardware the generally the thing that
22439
16:17:06,596 --> 16:17:07,596
you'll see with there is something
22440
16:17:07,616 --> 16:17:08,616
called a VPN concentrator it could also
22441
16:17:10,436 --> 16:17:11,436
be for instance built into your Soho
22442
16:17:11,936 --> 16:17:12,936
router or be built into a Cisco router
22443
16:17:14,756 --> 16:17:15,756
of some sort as well we also discussed
22444
16:17:16,740 --> 16:17:17,740
the two VPN protocols remember these
22445
16:17:19,980 --> 16:17:20,980
were the point-to-point tunneling
22446
16:17:21,900 --> 16:17:22,900
protocol and the layer 2 tunneling
22447
16:17:24,000 --> 16:17:25,000
protocol notice that these both you know
22448
16:17:26,700 --> 16:17:27,700
are VPN protocols because of this T the
22449
16:17:29,340 --> 16:17:30,340
tunneling protocol generally speaking
22450
16:17:31,320 --> 16:17:32,320
we're going to see l2tp used more than
22451
16:17:33,720 --> 16:17:34,720
pptp and what these really are
22452
16:17:36,240 --> 16:17:37,240
responsible for is defining how
22453
16:17:38,096 --> 16:17:39,096
encryption takes place
22454
16:17:41,880 --> 16:17:42,880
and authentication which is something
22455
16:17:44,700 --> 16:17:45,700
that works in conjunction with the VPN
22456
16:17:47,756 --> 16:17:48,756
server to accomplish
22457
16:17:52,230 --> 16:17:53,230
[Music]
22458
16:18:08,160 --> 16:18:09,160
welcome to module 10 lesson 4 gra SSL
22459
16:18:12,000 --> 16:18:13,000
VPN and VPN concentrators
22460
16:18:16,616 --> 16:18:17,616
we look at them
22461
16:18:18,480 --> 16:18:19,480
secure sockets for VPN also
22462
16:18:21,956 --> 16:18:22,956
what is SSL
22463
16:18:24,180 --> 16:18:25,180
VPN concentrators ipsec this is just an
22464
16:18:27,596 --> 16:18:28,596
overview
22465
16:18:28,796 --> 16:18:29,796
as usual there's a whole entire um exams
22466
16:18:32,880 --> 16:18:33,880
for security stuff like this in more
22467
16:18:34,680 --> 16:18:35,680
detail like the CompTIA Security Plus
22468
16:18:37,200 --> 16:18:38,200
which we host on howturnetwork.com and
22469
16:18:41,040 --> 16:18:42,040
the CCNA security also
22470
16:18:43,616 --> 16:18:44,616
GRE stands for generic routing
22471
16:18:45,660 --> 16:18:46,660
encapsulation and it was actually
22472
16:18:46,980 --> 16:18:47,980
developed by Cisco Systems as a
22473
16:18:49,320 --> 16:18:50,320
tunneling protocol and I totally in
22474
16:18:51,900 --> 16:18:52,900
protocol tunnels something else another
22475
16:18:54,956 --> 16:18:55,956
Prodigy call within a protocol
22476
16:18:59,520 --> 16:19:00,520
so it allows Network users to access the
22477
16:19:02,160 --> 16:19:03,160
network service it's not supported by
22478
16:19:03,720 --> 16:19:04,720
the underlying Network so you can
22479
16:19:05,340 --> 16:19:06,340
actually tunnel
22480
16:19:06,720 --> 16:19:07,720
um lots of different things you can sort
22481
16:19:08,160 --> 16:19:09,160
of IP version 4 inside IPv6 if the um
22482
16:19:14,340 --> 16:19:15,340
hop by hot pair devices don't support it
22483
16:19:18,000 --> 16:19:19,000
here is an image of a GRE tunnel going
22484
16:19:20,936 --> 16:19:21,936
across an internet
22485
16:19:22,796 --> 16:19:23,796
Source interface or IP address
22486
16:19:24,776 --> 16:19:25,776
destination IP address of the tunnel an
22487
16:19:27,660 --> 16:19:28,660
IP address of the tunnel that's part of
22488
16:19:29,456 --> 16:19:30,456
the configuration you don't really need
22489
16:19:30,956 --> 16:19:31,956
to worry about that
22490
16:19:32,456 --> 16:19:33,456
but the traffic will pass through the
22491
16:19:34,500 --> 16:19:35,500
GRE to Norm
22492
16:19:36,180 --> 16:19:37,180
and the device is actually sending the
22493
16:19:38,220 --> 16:19:39,220
traffic will only examine the header of
22494
16:19:41,276 --> 16:19:42,276
the GRE packet which is um wrapping the
22495
16:19:45,360 --> 16:19:46,360
uh the traditional IP traffic
22496
16:19:49,080 --> 16:19:50,080
so we already know we can run a protocol
22497
16:19:51,480 --> 16:19:52,480
every Network you can actually run
22498
16:19:53,276 --> 16:19:54,276
non-routable addresses as well so inside
22499
16:19:55,380 --> 16:19:56,380
that tunnel you could have a 192 address
22500
16:19:57,900 --> 16:19:58,900
and as long as the tunnel is going via
22501
16:20:00,240 --> 16:20:01,240
routable IP addresses you'll be fine
22502
16:20:04,020 --> 16:20:05,020
a gra creates a virtual point-to-point
22503
16:20:06,296 --> 16:20:07,296
link and encapsulates a variety of
22504
16:20:08,040 --> 16:20:09,040
network protocols
22505
16:20:10,680 --> 16:20:11,680
uh
22506
16:20:12,416 --> 16:20:13,416
yeah I've already mentioned the private
22507
16:20:14,160 --> 16:20:15,160
IP addresses it's used in conjunction
22508
16:20:16,200 --> 16:20:17,200
often with pptp point-to-point tunneling
22509
16:20:19,436 --> 16:20:20,436
protocol and ipsec if you want to create
22510
16:20:22,500 --> 16:20:23,500
a VPN and there's an image there for
22511
16:20:25,140 --> 16:20:26,140
with the GRE tunnel also working with an
22512
16:20:27,540 --> 16:20:28,540
IP sector null from networkstraining.com
22513
16:20:32,756 --> 16:20:33,756
uh VPN
22514
16:20:34,980 --> 16:20:35,980
a virtual Network a virtual private
22515
16:20:37,436 --> 16:20:38,436
network is a full term it's built on top
22516
16:20:39,596 --> 16:20:40,596
of an existing public network obviously
22517
16:20:41,936 --> 16:20:42,936
very handy if we need to securely
22518
16:20:43,740 --> 16:20:44,740
connect over the internet from
22519
16:20:46,680 --> 16:20:47,680
um two different network locations
22520
16:20:49,256 --> 16:20:50,256
often used by companies because they
22521
16:20:51,776 --> 16:20:52,776
don't want to buy a dedicated lease line
22522
16:20:53,580 --> 16:20:54,580
so they'll just use existing security
22523
16:20:56,640 --> 16:20:57,640
technology
22524
16:20:58,500 --> 16:20:59,500
you have a secure Communications between
22525
16:21:00,956 --> 16:21:01,956
two private Networks
22526
16:21:02,820 --> 16:21:03,820
SSL VPN this is a secure sockets layer
22527
16:21:06,360 --> 16:21:07,360
virtual private Network
22528
16:21:08,340 --> 16:21:09,340
it provides encrypted communication
22529
16:21:10,256 --> 16:21:11,256
between a clients and server one example
22530
16:21:13,200 --> 16:21:14,200
is SSL equips communication between a
22531
16:21:15,840 --> 16:21:16,840
web browser and a web server and your
22532
16:21:18,720 --> 16:21:19,720
browser will be a Google Chrome or
22533
16:21:21,180 --> 16:21:22,180
whatever you're running on your laptop
22534
16:21:22,740 --> 16:21:23,740
or PC
22535
16:21:24,540 --> 16:21:25,540
the user connects to VPN devices using
22536
16:21:27,116 --> 16:21:28,116
their web browsers traffic between the
22537
16:21:29,456 --> 16:21:30,456
web browser and the VPN is encrypted
22538
16:21:31,140 --> 16:21:32,140
with the SSL protocol
22539
16:21:35,400 --> 16:21:36,400
so as a result you've got a secure
22540
16:21:37,200 --> 16:21:38,200
access to web applications and client
22541
16:21:39,480 --> 16:21:40,480
server applications
22542
16:21:41,580 --> 16:21:42,580
you'll see this working with the um
22543
16:21:43,860 --> 16:21:44,860
green padlock when you're browsing
22544
16:21:46,916 --> 16:21:47,916
different websites built into all
22545
16:21:49,140 --> 16:21:50,140
standard web browsers you'd have to add
22546
16:21:51,060 --> 16:21:52,060
anything extra on you don't have to
22547
16:21:53,096 --> 16:21:54,096
configure or install any client software
22548
16:21:55,020 --> 16:21:56,020
anymore you used to have to that was a
22549
16:21:57,660 --> 16:21:58,660
few years ago now and it's all built
22550
16:21:59,160 --> 16:22:00,160
into the web browsers
22551
16:22:01,320 --> 16:22:02,320
uh the SSL VPN can be accessed from
22552
16:22:03,720 --> 16:22:04,720
anywhere including airport hotel rooms
22553
16:22:05,756 --> 16:22:06,756
coffee shops as long as you've got web
22554
16:22:08,096 --> 16:22:09,096
connectivity and the user has a standard
22555
16:22:10,916 --> 16:22:11,916
SSL client that's used with that
22556
16:22:12,540 --> 16:22:13,540
particular SSL VPN
22557
16:22:15,840 --> 16:22:16,840
uh SSL VPN products usually Standalone
22558
16:22:19,080 --> 16:22:20,080
Hardware Appliances and other software
22559
16:22:21,900 --> 16:22:22,900
Solutions available speak to uh whatever
22560
16:22:25,020 --> 16:22:26,020
the whoever the sales representative is
22561
16:22:27,296 --> 16:22:28,296
for Cisco or whoever you're using for
22562
16:22:29,880 --> 16:22:30,880
the technology
22563
16:22:31,740 --> 16:22:32,740
you also get common security services
22564
16:22:33,540 --> 16:22:34,540
such as authentication encryption
22565
16:22:36,596 --> 16:22:37,596
Integrity protection Access Control who
22566
16:22:39,720 --> 16:22:40,720
can access
22567
16:22:41,040 --> 16:22:42,040
even how long they can access for
22568
16:22:43,276 --> 16:22:44,276
security and endpoint security controls
22569
16:22:47,096 --> 16:22:48,096
in choosing prevention IPS
22570
16:22:51,796 --> 16:22:52,796
authentication as we know I'm sure is
22571
16:22:54,296 --> 16:22:55,296
just authenticating that particular
22572
16:22:55,860 --> 16:22:56,860
person to verify they are who they say
22573
16:22:58,140 --> 16:22:59,140
they are encryption encryption protects
22574
16:23:00,840 --> 16:23:01,840
the con
22575
16:23:02,416 --> 16:23:03,416
confidentiality of the data as it passes
22576
16:23:05,340 --> 16:23:06,340
through through the internet
22577
16:23:08,580 --> 16:23:09,580
Integrity ensures that the data is not
22578
16:23:10,680 --> 16:23:11,680
altered so
22579
16:23:12,360 --> 16:23:13,360
um there's a whole bunch of ways to um
22580
16:23:14,820 --> 16:23:15,820
showing and offer Integrity of the data
22581
16:23:18,540 --> 16:23:19,540
as it's sent from the source and
22582
16:23:20,756 --> 16:23:21,756
received at the destination
22583
16:23:22,860 --> 16:23:23,860
Access Control gives restricted access
22584
16:23:25,020 --> 16:23:26,020
and that can be based upon a number of
22585
16:23:27,060 --> 16:23:28,060
things and the access control is then
22586
16:23:29,480 --> 16:23:30,480
associated with whatever privilege is
22587
16:23:31,796 --> 16:23:32,796
you wanted to give that particular user
22588
16:23:35,360 --> 16:23:36,360
the endpoint security controls checks
22589
16:23:37,860 --> 16:23:38,860
the user system for compliance whenever
22590
16:23:39,596 --> 16:23:40,596
the user attempts to use the SSL VPN
22591
16:23:45,296 --> 16:23:46,296
intrusion prevention checks the data for
22592
16:23:47,520 --> 16:23:48,520
any Potential Threat after it's been
22593
16:23:49,080 --> 16:23:50,080
decrypted
22594
16:23:50,700 --> 16:23:51,700
VPN concentrators these were supported
22595
16:23:54,060 --> 16:23:55,060
originally when I worked at Cisco by the
22596
16:23:56,520 --> 16:23:57,520
security team
22597
16:23:57,840 --> 16:23:58,840
they provide a remote user with secure
22598
16:23:59,880 --> 16:24:00,880
access to the organization's resources
22599
16:24:02,096 --> 16:24:03,096
and the concentrator is basically an
22600
16:24:04,256 --> 16:24:05,256
endpoint for multiple VPN connections so
22601
16:24:07,256 --> 16:24:08,256
there's maybe lots of Home users or
22602
16:24:09,000 --> 16:24:10,000
people dialing in and
22603
16:24:12,180 --> 16:24:13,180
Mobile sales people that need to connect
22604
16:24:14,936 --> 16:24:15,936
from certain places and the VPN
22605
16:24:16,500 --> 16:24:17,500
concentrator will be the point where
22606
16:24:18,416 --> 16:24:19,416
their connection is terminated
22607
16:24:22,500 --> 16:24:23,500
all right uh the concentrate is a device
22608
16:24:24,900 --> 16:24:25,900
it can handle multiple tunnels coming in
22609
16:24:28,560 --> 16:24:29,560
a VPN they provide VPN encryption either
22610
16:24:31,740 --> 16:24:32,740
by using ipsec or SSL
22611
16:24:34,560 --> 16:24:35,560
again check with your vendor for
22612
16:24:37,320 --> 16:24:38,320
documentation
22613
16:24:38,700 --> 16:24:39,700
ipsec is IP security provides a high
22614
16:24:41,756 --> 16:24:42,756
level of security and encryption and
22615
16:24:44,580 --> 16:24:45,580
because client software to establish the
22616
16:24:46,860 --> 16:24:47,860
VPN tunnel
22617
16:24:50,040 --> 16:24:51,040
ipsec is better for fixed locations SSR
22618
16:24:53,040 --> 16:24:54,040
when the remote users need to connect
22619
16:24:54,480 --> 16:24:55,480
from various locations for example
22620
16:24:57,116 --> 16:24:58,116
they're a traveling salesperson
22621
16:25:00,776 --> 16:25:01,776
and nowadays VPN concentrators are not
22622
16:25:03,660 --> 16:25:04,660
manufactured as separate devices they
22623
16:25:06,720 --> 16:25:07,720
normally combined with devices that also
22624
16:25:08,400 --> 16:25:09,400
provide firewall protection if you go to
22625
16:25:10,680 --> 16:25:11,680
cisco.com and then click on I think it's
22626
16:25:12,956 --> 16:25:13,956
sales or products you'll see the type of
22627
16:25:15,416 --> 16:25:16,416
devices that are available and what they
22628
16:25:17,160 --> 16:25:18,160
do
22629
16:25:18,480 --> 16:25:19,480
all right so we've covered a fair bit
22630
16:25:20,160 --> 16:25:21,160
GRE tunneling VPN SSL
22631
16:25:25,980 --> 16:25:26,980
Security Services of SSL VPN and a VPN
22632
16:25:29,520 --> 16:25:30,520
concentrator on ipsec
22633
16:25:32,276 --> 16:25:33,276
that's all for now thanks for watching
22634
16:25:39,330 --> 16:25:40,330
[Music]
22635
16:25:59,360 --> 16:26:00,360
Network management Network
22636
16:26:01,860 --> 16:26:02,860
Administration
22637
16:26:03,956 --> 16:26:04,956
in the previous lessons we've talked
22638
16:26:05,640 --> 16:26:06,640
about a lot of the technical aspects of
22639
16:26:08,096 --> 16:26:09,096
networking including remote networking
22640
16:26:10,320 --> 16:26:11,320
remote access virtual private networks
22641
16:26:13,256 --> 16:26:14,256
local area networks wide area networks
22642
16:26:15,360 --> 16:26:16,360
and so on there's someone who's required
22643
16:26:17,400 --> 16:26:18,400
to sort of put all of this into place
22644
16:26:19,500 --> 16:26:20,500
and that's where an administrator comes
22645
16:26:21,480 --> 16:26:22,480
in so in this lesson and in the
22646
16:26:23,936 --> 16:26:24,936
following modules I want to talk about
22647
16:26:26,276 --> 16:26:27,276
what an administrator is and some of the
22648
16:26:29,580 --> 16:26:30,580
tasks they have to do in this module in
22649
16:26:31,980 --> 16:26:32,980
specific we're going to start by
22650
16:26:33,240 --> 16:26:34,240
defining an administrator or network
22651
16:26:35,340 --> 16:26:36,340
administrator now there can be several
22652
16:26:37,740 --> 16:26:38,740
administrators at any one's site but
22653
16:26:39,416 --> 16:26:40,416
we're going to give an overview of what
22654
16:26:40,796 --> 16:26:41,796
an administrator no matter what their
22655
16:26:42,416 --> 16:26:43,416
specific role is going to do then we're
22656
16:26:44,820 --> 16:26:45,820
going to identify some of the key admin
22657
16:26:46,860 --> 16:26:47,860
duties and these might be documentation
22658
16:26:49,700 --> 16:26:50,700
and monitoring we'll talk more about
22659
16:26:52,500 --> 16:26:53,500
these in further modules and we've
22660
16:26:54,296 --> 16:26:55,296
probably already mentioned already
22661
16:26:55,500 --> 16:26:56,500
mentioned these to some degree so some
22662
16:26:58,256 --> 16:26:59,256
of this might be recap in some cases it
22663
16:27:00,900 --> 16:27:01,900
might be overview but a lot of what's on
22664
16:27:02,700 --> 16:27:03,700
the network plus exam is is sort of
22665
16:27:04,916 --> 16:27:05,916
applying not just having knowledge but
22666
16:27:07,916 --> 16:27:08,916
applying the knowledge in certain
22667
16:27:09,480 --> 16:27:10,480
administrator roles since that's what
22668
16:27:11,160 --> 16:27:12,160
they assume you're going to do with your
22669
16:27:12,776 --> 16:27:13,776
certification
22670
16:27:14,276 --> 16:27:15,276
so there's no doubt that we have used
22671
16:27:16,740 --> 16:27:17,740
administrator or admin for short
22672
16:27:21,480 --> 16:27:22,480
in uh hundreds of times by now so it
22673
16:27:25,020 --> 16:27:26,020
might be useful to stop for a minute and
22674
16:27:26,756 --> 16:27:27,756
actually take time to talk about what
22675
16:27:28,680 --> 16:27:29,680
this term means so the administrator of
22676
16:27:30,776 --> 16:27:31,776
a network is the most important person
22677
16:27:33,296 --> 16:27:34,296
involved in network it they are in
22678
16:27:36,180 --> 16:27:37,180
charge of everything that happens on the
22679
16:27:38,040 --> 16:27:39,040
network and know what all of the users
22680
16:27:41,160 --> 16:27:42,160
are doing in charge of security and they
22681
16:27:43,380 --> 16:27:44,380
can be held responsible for everything
22682
16:27:45,000 --> 16:27:46,000
that happens on their Network so not
22683
16:27:47,096 --> 16:27:48,096
only are they responsible for sort of
22684
16:27:48,596 --> 16:27:49,596
creating the network but if someone
22685
16:27:50,520 --> 16:27:51,520
misuses the network the really acts is
22686
16:27:52,740 --> 16:27:53,740
going to fall on them more than that
22687
16:27:54,776 --> 16:27:55,776
they're in control of all the accounts
22688
16:27:56,580 --> 16:27:57,580
the resources the data that users have
22689
16:27:58,916 --> 16:27:59,916
access to the administrator is the only
22690
16:28:01,320 --> 16:28:02,320
person that has access to everything in
22691
16:28:03,596 --> 16:28:04,596
the network and can control what others
22692
16:28:05,520 --> 16:28:06,520
can access even if they give access to
22693
16:28:07,916 --> 16:28:08,916
say an assistant administrator in the
22694
16:28:10,320 --> 16:28:11,320
end if that assistant administrator
22695
16:28:11,640 --> 16:28:12,640
screws something up it was the
22696
16:28:13,500 --> 16:28:14,500
administrator who gave them access in
22697
16:28:15,480 --> 16:28:16,480
the first place so clearly this is a
22698
16:28:17,820 --> 16:28:18,820
really important person and are
22699
16:28:19,796 --> 16:28:20,796
essential to managing and monitoring the
22700
16:28:21,840 --> 16:28:22,840
network without them there really
22701
16:28:23,160 --> 16:28:24,160
wouldn't be anyone with enough knowledge
22702
16:28:26,160 --> 16:28:27,160
or ability to manage how these networks
22703
16:28:28,680 --> 16:28:29,680
and you can see how large they get
22704
16:28:30,840 --> 16:28:31,840
sometimes
22705
16:28:32,040 --> 16:28:33,040
so here is essentially what an
22706
16:28:34,320 --> 16:28:35,320
administrator's view might be like they
22707
16:28:37,140 --> 16:28:38,140
have a view of everything that happens
22708
16:28:38,580 --> 16:28:39,580
going in right they know all of the
22709
16:28:41,040 --> 16:28:42,040
nodes all of the servers and this is
22710
16:28:43,500 --> 16:28:44,500
very simplified all of the routers and
22711
16:28:45,540 --> 16:28:46,540
switches this is what we might call a
22712
16:28:46,860 --> 16:28:47,860
network diagram we might also have
22713
16:28:49,320 --> 16:28:50,320
printers
22714
16:28:51,360 --> 16:28:52,360
and if this is a cloud environment as it
22715
16:28:54,360 --> 16:28:55,360
seems to be then they're going to be
22716
16:28:56,340 --> 16:28:57,340
aware of all the virtual sort of stuff
22717
16:28:58,500 --> 16:28:59,500
that is set up
22718
16:29:01,020 --> 16:29:02,020
they're going to beware of all of the
22719
16:29:04,140 --> 16:29:05,140
user accounts
22720
16:29:07,160 --> 16:29:08,160
the network security
22721
16:29:11,220 --> 16:29:12,220
they're also going to be dealing with
22722
16:29:13,740 --> 16:29:14,740
all the remote access
22723
16:29:17,520 --> 16:29:18,520
if there is this going out to the
22724
16:29:20,096 --> 16:29:21,096
internet are there firewalls
22725
16:29:24,116 --> 16:29:25,116
are there intrusion systems etc etc so
22726
16:29:28,080 --> 16:29:29,080
they really have an overview of
22727
16:29:29,520 --> 16:29:30,520
everything they have to maintain
22728
16:29:30,956 --> 16:29:31,956
everything as well you can see how
22729
16:29:32,700 --> 16:29:33,700
complicated this can get which is the
22730
16:29:34,080 --> 16:29:35,080
reason why one network administrator
22731
16:29:35,640 --> 16:29:36,640
might have several under administrators
22732
16:29:37,916 --> 16:29:38,916
to help them they not only log when
22733
16:29:41,096 --> 16:29:42,096
someone comes in or out they can see
22734
16:29:42,840 --> 16:29:43,840
when someone visits a specific website
22735
16:29:45,116 --> 16:29:46,116
when they're sending or where they're
22736
16:29:47,220 --> 16:29:48,220
sending data what the type of data is we
22737
16:29:50,220 --> 16:29:51,220
might also have for instance an exchange
22738
16:29:52,380 --> 16:29:53,380
server which would be for email in which
22739
16:29:54,720 --> 16:29:55,720
case we need someone to manage that as
22740
16:29:56,456 --> 16:29:57,456
well for instance what if someone sends
22741
16:29:58,796 --> 16:29:59,796
a 50 megabyte or 50 gigabyte file by
22742
16:30:01,616 --> 16:30:02,616
email or they try to that's going to log
22743
16:30:03,660 --> 16:30:04,660
up the entire network
22744
16:30:05,580 --> 16:30:06,580
so one of the first duties of an
22745
16:30:07,860 --> 16:30:08,860
administrator is documentation there's a
22746
16:30:09,900 --> 16:30:10,900
couple reasons why this is so important
22747
16:30:12,180 --> 16:30:13,180
when it comes to managing and running a
22748
16:30:15,660 --> 16:30:16,660
network it's going to be the focus of
22749
16:30:17,936 --> 16:30:18,936
its own module but it's good to get a
22750
16:30:19,796 --> 16:30:20,796
basic understanding right now because
22751
16:30:21,540 --> 16:30:22,540
the process of documenting everything
22752
16:30:23,160 --> 16:30:24,160
can be really time consuming but it's
22753
16:30:25,256 --> 16:30:26,256
also really worth it can save you a lot
22754
16:30:27,296 --> 16:30:28,296
of time trouble and money when things
22755
16:30:29,276 --> 16:30:30,276
are well documented and no one has to go
22756
16:30:31,256 --> 16:30:32,256
searching for them especially if the
22757
16:30:33,720 --> 16:30:34,720
administrator is out of town or if we
22758
16:30:35,820 --> 16:30:36,820
switch administrators we want to make
22759
16:30:37,200 --> 16:30:38,200
sure that the network can still live on
22760
16:30:38,936 --> 16:30:39,936
its own now there are no shortage of
22761
16:30:40,916 --> 16:30:41,916
things to handle for the administrator
22762
16:30:42,296 --> 16:30:43,296
and documentation is OB usually the
22763
16:30:45,296 --> 16:30:46,296
thing that's going to get pushed aside
22764
16:30:47,160 --> 16:30:48,160
and forgotten about but there are some
22765
16:30:49,020 --> 16:30:50,020
really key items that we can look over
22766
16:30:51,596 --> 16:30:52,596
that are helpful to be dealt with first
22767
16:30:54,060 --> 16:30:55,060
of all properly documenting information
22768
16:30:55,936 --> 16:30:56,936
is useful when training new admins it's
22769
16:30:59,456 --> 16:31:00,456
not uncommon for the old administrator
22770
16:31:00,900 --> 16:31:01,900
to leave and then have to train a new
22771
16:31:03,060 --> 16:31:04,060
one is their replacement however the new
22772
16:31:04,740 --> 16:31:05,740
admin doesn't have time to learn the
22773
16:31:06,060 --> 16:31:07,060
topography the cable connections
22774
16:31:07,680 --> 16:31:08,680
everything about the network from
22775
16:31:09,060 --> 16:31:10,060
scratch so this is where proper
22776
16:31:10,436 --> 16:31:11,436
documentation is really helpful it can
22777
16:31:12,720 --> 16:31:13,720
save the new administrator a lot of time
22778
16:31:14,456 --> 16:31:15,456
and effort especially if even if you're
22779
16:31:16,796 --> 16:31:17,796
not leaving if you bring on someone to
22780
16:31:18,596 --> 16:31:19,596
assist you allowing them to look at
22781
16:31:20,096 --> 16:31:21,096
documentation is going to save the super
22782
16:31:22,680 --> 16:31:23,680
administrator time from having to teach
22783
16:31:24,480 --> 16:31:25,480
the new administrator
22784
16:31:26,096 --> 16:31:27,096
it's also going to help us when we
22785
16:31:28,860 --> 16:31:29,860
troubleshoot problems on the network it
22786
16:31:31,200 --> 16:31:32,200
can save time and money because we can
22787
16:31:32,820 --> 16:31:33,820
eliminate the time it takes to test
22788
16:31:34,380 --> 16:31:35,380
every possible problem because we can
22789
16:31:36,840 --> 16:31:37,840
now isolate where the potential problems
22790
16:31:38,640 --> 16:31:39,640
are for instance if I have an overview
22791
16:31:40,980 --> 16:31:41,980
of where things are set on the network
22792
16:31:43,200 --> 16:31:44,200
and I know one side of the Network's not
22793
16:31:44,700 --> 16:31:45,700
working then I can automatically sort of
22794
16:31:46,796 --> 16:31:47,796
go to that side of the network and not
22795
16:31:48,240 --> 16:31:49,240
have to worry about the other side
22796
16:31:49,560 --> 16:31:50,560
finally it's also really important when
22797
16:31:52,616 --> 16:31:53,616
I'm bringing in outside workers to make
22798
16:31:55,500 --> 16:31:56,500
changes to the network they need
22799
16:31:57,116 --> 16:31:58,116
accurate and up-to-date information
22800
16:31:58,320 --> 16:31:59,320
about the network its layout and if
22801
16:32:02,936 --> 16:32:03,936
they don't have an idea of how my
22802
16:32:05,220 --> 16:32:06,220
network looks and I just start to tell
22803
16:32:06,956 --> 16:32:07,956
them to fix things they're going to have
22804
16:32:08,820 --> 16:32:09,820
major issues and one of the things
22805
16:32:10,140 --> 16:32:11,140
that's really big these days is having a
22806
16:32:12,720 --> 16:32:13,720
contractor come in because we're sort of
22807
16:32:14,880 --> 16:32:15,880
going to Outsource a lot of our network
22808
16:32:16,740 --> 16:32:17,740
administrator duties or sometimes the
22809
16:32:18,840 --> 16:32:19,840
administrator is not a specialist in
22810
16:32:21,660 --> 16:32:22,660
something Sprints in security and so
22811
16:32:23,340 --> 16:32:24,340
they need to bring in contractors to
22812
16:32:24,720 --> 16:32:25,720
implement a better security plan
22813
16:32:27,180 --> 16:32:28,180
now monitoring is also an extremely
22814
16:32:29,340 --> 16:32:30,340
important job for the administrator it's
22815
16:32:30,956 --> 16:32:31,956
necessary to monitor a network for a lot
22816
16:32:32,936 --> 16:32:33,936
of reasons and again we're going to talk
22817
16:32:34,616 --> 16:32:35,616
talk about this in its own module but
22818
16:32:36,720 --> 16:32:37,720
it's good to understand it a little bit
22819
16:32:38,096 --> 16:32:39,096
right now so when you monitor a network
22820
16:32:40,880 --> 16:32:41,880
the administrator can almost always find
22821
16:32:43,740 --> 16:32:44,740
faults in the system and find out where
22822
16:32:45,660 --> 16:32:46,660
they are there are tools that help the
22823
16:32:47,456 --> 16:32:48,456
administrator check all the devices to
22824
16:32:49,560 --> 16:32:50,560
find out where the faults are and how
22825
16:32:50,700 --> 16:32:51,700
they can be fixed and I think we've
22826
16:32:51,900 --> 16:32:52,900
looked at some of those and we might
22827
16:32:53,220 --> 16:32:54,220
look at it a couple more but some of the
22828
16:32:55,200 --> 16:32:56,200
tools the Ping trace route Etc looking
22829
16:32:58,080 --> 16:32:59,080
at routing tables looking at broadcast
22830
16:33:00,080 --> 16:33:01,080
all this stuff and also performance
22831
16:33:02,936 --> 16:33:03,936
detection is very important when we're
22832
16:33:05,456 --> 16:33:06,456
involved with network monitoring when an
22833
16:33:07,380 --> 16:33:08,380
administrator monitors performance
22834
16:33:08,880 --> 16:33:09,880
they're able to find some very useful
22835
16:33:10,740 --> 16:33:11,740
data they can discover Network usage
22836
16:33:12,720 --> 16:33:13,720
data how each user has been using the
22837
16:33:14,936 --> 16:33:15,936
network and make sure that the bandwidth
22838
16:33:16,860 --> 16:33:17,860
is load balanced properly a term that we
22839
16:33:20,456 --> 16:33:21,456
have seen a bit and we're probably going
22840
16:33:22,200 --> 16:33:23,200
to see a little more
22841
16:33:23,880 --> 16:33:24,880
and also we can make sure that nothing
22842
16:33:26,700 --> 16:33:27,700
if there's not too much traffic on the
22843
16:33:28,500 --> 16:33:29,500
system obviously too much traffic slows
22844
16:33:30,416 --> 16:33:31,416
things down and makes everyone miserable
22845
16:33:32,180 --> 16:33:33,180
finally security monitoring is really
22846
16:33:35,160 --> 16:33:36,160
essential because uh one thing we don't
22847
16:33:38,456 --> 16:33:39,456
want is someone outside of our Network
22848
16:33:40,080 --> 16:33:41,080
getting access to all the stuff we set
22849
16:33:41,640 --> 16:33:42,640
up it's really going to make your bosses
22850
16:33:42,956 --> 16:33:43,956
upset too and we're not just talking
22851
16:33:44,520 --> 16:33:45,520
about hackers we're talking about
22852
16:33:45,660 --> 16:33:46,660
viruses attackers any of this stuff so
22853
16:33:48,416 --> 16:33:49,416
when we're monitoring security an
22854
16:33:49,916 --> 16:33:50,916
administrator can find holes in the
22855
16:33:51,776 --> 16:33:52,776
system and then take preventative
22856
16:33:53,400 --> 16:33:54,400
actions in order to stop the attacks
22857
16:33:55,436 --> 16:33:56,436
before they happen one thing that's
22858
16:33:57,000 --> 16:33:58,000
going to help with this are two devices
22859
16:33:58,560 --> 16:33:59,560
called an IPS or an IDs an intrusion
22860
16:34:05,276 --> 16:34:06,276
detection system
22861
16:34:08,400 --> 16:34:09,400
and then an intrusion
22862
16:34:12,240 --> 16:34:13,240
prevention system
22863
16:34:15,296 --> 16:34:16,296
these are actually two different things
22864
16:34:17,040 --> 16:34:18,040
as you can see from the name intrusion
22865
16:34:18,776 --> 16:34:19,776
detection just detects when something
22866
16:34:20,456 --> 16:34:21,456
happens intrusion prevention is actually
22867
16:34:22,560 --> 16:34:23,560
going to stop it in its tracks so that
22868
16:34:24,776 --> 16:34:25,776
was just a broad overview of defining
22869
16:34:27,180 --> 16:34:28,180
what an administrator does the person
22870
16:34:28,740 --> 16:34:29,740
who overview who has a complete overview
22871
16:34:32,400 --> 16:34:33,400
of the network
22872
16:34:34,080 --> 16:34:35,080
and then we looked at a couple of the
22873
16:34:36,000 --> 16:34:37,000
reasons why their admin duties of the
22874
16:34:38,580 --> 16:34:39,580
documentation monitoring are so
22875
16:34:39,956 --> 16:34:40,956
important documentation for training new
22876
16:34:43,020 --> 16:34:44,020
people
22877
16:34:44,400 --> 16:34:45,400
tech support
22878
16:34:48,320 --> 16:34:49,320
uh bringing in outside resources
22879
16:34:53,520 --> 16:34:54,520
and also monitoring not just for uh
22880
16:34:56,580 --> 16:34:57,580
security reasons
22881
16:34:58,500 --> 16:34:59,500
but also for performance
22882
16:35:01,200 --> 16:35:02,200
because obviously if we have a slow
22883
16:35:02,640 --> 16:35:03,640
Network it's going to result in everyone
22884
16:35:05,040 --> 16:35:06,040
being unhappy and your boss is not being
22885
16:35:07,256 --> 16:35:08,256
able to be able to accomplish the work
22886
16:35:09,596 --> 16:35:10,596
they need not to mention if we talk
22887
16:35:11,756 --> 16:35:12,756
about one extra minute in work time that
22888
16:35:13,916 --> 16:35:14,916
can actually cost us quite a bit of
22889
16:35:15,900 --> 16:35:16,900
money in the real world so having giving
22890
16:35:17,880 --> 16:35:18,880
us a broad overview of this we're going
22891
16:35:19,616 --> 16:35:20,616
to talk more about uh optimizing a
22892
16:35:23,160 --> 16:35:24,160
network Performance Based on the
22893
16:35:24,660 --> 16:35:25,660
monitoring that we do
22894
16:35:29,730 --> 16:35:30,730
[Music]
22895
16:35:38,416 --> 16:35:39,416
thank you
22896
16:35:49,436 --> 16:35:50,436
Network management optimizing Network
22897
16:35:52,436 --> 16:35:53,436
performance
22898
16:35:54,240 --> 16:35:55,240
we're going to be covering a lot in this
22899
16:35:55,616 --> 16:35:56,616
module it's all about the optimization
22900
16:35:57,720 --> 16:35:58,720
of a network and its performance and
22901
16:36:00,596 --> 16:36:01,596
there's a lot that we have to do as
22902
16:36:02,096 --> 16:36:03,096
administrators when it comes to that
22903
16:36:03,540 --> 16:36:04,540
we're going to specifically focus on
22904
16:36:06,116 --> 16:36:07,116
strategies to optimize network speed and
22905
16:36:09,720 --> 16:36:10,720
efficiency
22906
16:36:10,916 --> 16:36:11,916
so first we're going to give an overview
22907
16:36:13,436 --> 16:36:14,436
of what network optimization is and then
22908
16:36:16,020 --> 16:36:17,020
we're going to define something called
22909
16:36:17,220 --> 16:36:18,220
quality of service qos which I want to
22910
16:36:20,700 --> 16:36:21,700
point out right now you're going to see
22911
16:36:22,256 --> 16:36:23,256
anytime we talk about voice over IP this
22912
16:36:25,200 --> 16:36:26,200
is the name implies what we're doing is
22913
16:36:27,240 --> 16:36:28,240
trying to make sure the service provided
22914
16:36:30,000 --> 16:36:31,000
on our network has a high degree of
22915
16:36:31,860 --> 16:36:32,860
quality and when it comes to voice over
22916
16:36:33,840 --> 16:36:34,840
IP we need to make sure the quality is
22917
16:36:35,880 --> 16:36:36,880
pretty high
22918
16:36:36,956 --> 16:36:37,956
there are two ways to do this one is
22919
16:36:39,180 --> 16:36:40,180
called latency sensitive and the other
22920
16:36:41,400 --> 16:36:42,400
is latency insensitive and we'll Define
22921
16:36:43,500 --> 16:36:44,500
that a bit more
22922
16:36:44,820 --> 16:36:45,820
we're also going to talk about something
22923
16:36:46,200 --> 16:36:47,200
called traffic shaping and methods in
22924
16:36:49,380 --> 16:36:50,380
which we do this and finally caching
22925
16:36:51,900 --> 16:36:52,900
engines which help speed up Network
22926
16:36:54,180 --> 16:36:55,180
performance as well
22927
16:36:56,220 --> 16:36:57,220
so
22928
16:36:57,320 --> 16:36:58,320
bandwidth is essentially the amount of
22929
16:37:00,000 --> 16:37:01,000
data that can be transferred and
22930
16:37:01,680 --> 16:37:02,680
utilized at any given time this amount
22931
16:37:04,200 --> 16:37:05,200
is usually expressed in bits per second
22932
16:37:06,240 --> 16:37:07,240
so if you remember we see for instance
22933
16:37:09,116 --> 16:37:10,116
mega bits per second with the small B
22934
16:37:12,416 --> 16:37:13,416
and I want to point out again that this
22935
16:37:14,040 --> 16:37:15,040
is not megabytes per second as you
22936
16:37:16,256 --> 16:37:17,256
recall there are eight bits
22937
16:37:19,140 --> 16:37:20,140
in every bite
22938
16:37:21,720 --> 16:37:22,720
so we would really need eight
22939
16:37:26,096 --> 16:37:27,096
mega bits per second to equal one
22940
16:37:29,700 --> 16:37:30,700
megabyte per second just something to
22941
16:37:32,520 --> 16:37:33,520
keep in mind as you purchase uh perhaps
22942
16:37:35,756 --> 16:37:36,756
a broadband connection now how the
22943
16:37:38,340 --> 16:37:39,340
bandwidth flows is dependent on how many
22944
16:37:41,756 --> 16:37:42,756
people are using it at once and for what
22945
16:37:43,616 --> 16:37:44,616
purpose so everything in today's world
22946
16:37:45,720 --> 16:37:46,720
is expected to be fast and we can settle
22947
16:37:47,936 --> 16:37:48,936
for no less than the fastest it will
22948
16:37:50,276 --> 16:37:51,276
become really impatient with network
22949
16:37:51,840 --> 16:37:52,840
speeds very easily and unfortunately
22950
16:37:53,880 --> 16:37:54,880
they fluctuate fairly easily too
22951
16:37:55,380 --> 16:37:56,380
especially in a corporate environment
22952
16:37:57,596 --> 16:37:58,596
where there are a lot of people using
22953
16:37:59,400 --> 16:38:00,400
and taking up the same bandwidth just
22954
16:38:01,436 --> 16:38:02,436
imagine how frustrated workers are going
22955
16:38:04,500 --> 16:38:05,500
to become with uh when they can access
22956
16:38:07,256 --> 16:38:08,256
something really fast one second and
22957
16:38:09,116 --> 16:38:10,116
very slow the next you can imagine this
22958
16:38:10,680 --> 16:38:11,680
at home as well
22959
16:38:11,936 --> 16:38:12,936
so the purpose of network optimization
22960
16:38:14,820 --> 16:38:15,820
is really to help control the traffic on
22961
16:38:17,520 --> 16:38:18,520
a network the large group of people are
22962
16:38:19,616 --> 16:38:20,616
trying to enter a building through one
22963
16:38:21,480 --> 16:38:22,480
door the flow is going to be a lot
22964
16:38:22,980 --> 16:38:23,980
slower than if there are multiple doors
22965
16:38:25,740 --> 16:38:26,740
and the same principle applies to
22966
16:38:27,956 --> 16:38:28,956
networks if the network is laid out and
22967
16:38:30,060 --> 16:38:31,060
run in an optimal way there is less
22968
16:38:32,276 --> 16:38:33,276
chance of blockage so in addition to
22969
16:38:35,220 --> 16:38:36,220
network traffic optimization Works to
22970
16:38:37,680 --> 16:38:38,680
utilize bandwidth in the best possible
22971
16:38:39,840 --> 16:38:40,840
way so that everyone can use it at the
22972
16:38:42,360 --> 16:38:43,360
same time this would be also called
22973
16:38:44,936 --> 16:38:45,936
throughput
22974
16:38:46,680 --> 16:38:47,680
so whereas bandwidth
22975
16:38:50,580 --> 16:38:51,580
is our ideal or possible
22976
16:38:56,160 --> 16:38:57,160
throughput
22977
16:38:59,040 --> 16:39:00,040
is the actual
22978
16:39:00,840 --> 16:39:01,840
in other words what actually makes it
22979
16:39:03,116 --> 16:39:04,116
through the bandwidth
22980
16:39:04,616 --> 16:39:05,616
so here's a representation of what
22981
16:39:06,296 --> 16:39:07,296
bandwidth might look like imagine the
22982
16:39:08,340 --> 16:39:09,340
bandwidth capabilities are like tubes
22983
16:39:11,040 --> 16:39:12,040
and the bigger the tube the more that is
22984
16:39:13,256 --> 16:39:14,256
free to throw flow through it so here
22985
16:39:15,900 --> 16:39:16,900
you can see there's much more ability to
22986
16:39:17,640 --> 16:39:18,640
flow through the tube on the right
22987
16:39:19,020 --> 16:39:20,020
because it's a lot bigger than the tube
22988
16:39:21,480 --> 16:39:22,480
on the left that being said only because
22989
16:39:24,480 --> 16:39:25,480
our bandwidth is for instance 90
22990
16:39:27,060 --> 16:39:28,060
megabits per second or one gigabit per
22991
16:39:30,480 --> 16:39:31,480
second doesn't mean that the throughput
22992
16:39:32,756 --> 16:39:33,756
is actually going to be that I'm sure
22993
16:39:35,276 --> 16:39:36,276
that you have at home uh bandwidth or
22994
16:39:39,660 --> 16:39:40,660
broadband internet
22995
16:39:41,220 --> 16:39:42,220
and it probably says it has up to
22996
16:39:43,200 --> 16:39:44,200
perhaps maybe 15 megabits per second if
22997
16:39:45,840 --> 16:39:46,840
you're on cable but sometimes you're not
22998
16:39:47,640 --> 16:39:48,640
always getting 15 megabits per second
22999
16:39:49,140 --> 16:39:50,140
you might be getting five or eight
23000
16:39:51,660 --> 16:39:52,660
megabits per second and you can test
23001
16:39:54,000 --> 16:39:55,000
this using different sort of online
23002
16:39:55,560 --> 16:39:56,560
speed test uh utilities but only because
23003
16:39:59,520 --> 16:40:00,520
we have a certain amount of bandwidth
23004
16:40:01,380 --> 16:40:02,380
doesn't mean our throughput is going to
23005
16:40:03,116 --> 16:40:04,116
equal that which is an important
23006
16:40:04,796 --> 16:40:05,796
distinction
23007
16:40:06,840 --> 16:40:07,840
to make
23008
16:40:11,456 --> 16:40:12,456
what we want to do is get the bandwidth
23009
16:40:13,980 --> 16:40:14,980
and throughput to equal as close as
23010
16:40:15,596 --> 16:40:16,596
possible to one another
23011
16:40:17,220 --> 16:40:18,220
so there are strategies used to increase
23012
16:40:20,040 --> 16:40:21,040
the use and optimization of bandwidth on
23013
16:40:22,860 --> 16:40:23,860
a network
23014
16:40:23,700 --> 16:40:24,700
these strategies are called quality of
23015
16:40:26,880 --> 16:40:27,880
service or short-term qos
23016
16:40:30,296 --> 16:40:31,296
now they have a lot to do with
23017
16:40:32,520 --> 16:40:33,520
information and helping it optimize the
23018
16:40:35,700 --> 16:40:36,700
network so qos allows administrators to
23019
16:40:38,936 --> 16:40:39,936
predict the bandwidth use on their
23020
16:40:40,796 --> 16:40:41,796
Network monitor the use of it and then
23021
16:40:43,436 --> 16:40:44,436
control it this is done to make sure
23022
16:40:45,416 --> 16:40:46,416
that there is available bandwidth for
23023
16:40:47,276 --> 16:40:48,276
any one application that requires it the
23024
16:40:49,980 --> 16:40:50,980
applications that need this bandwidth
23025
16:40:51,480 --> 16:40:52,480
are generally split into two different
23026
16:40:52,796 --> 16:40:53,796
categories
23027
16:40:54,020 --> 16:40:55,020
latency sensitive and
23028
16:40:57,900 --> 16:40:58,900
latency insensitive latency sensitive
23029
16:41:01,140 --> 16:41:02,140
applications are appropriately named
23030
16:41:02,820 --> 16:41:03,820
these are applications that are affected
23031
16:41:05,220 --> 16:41:06,220
by latency or a delay caused by a device
23032
16:41:10,616 --> 16:41:11,616
so latency is sort of the slowness with
23033
16:41:14,340 --> 16:41:15,340
which bandwidth occurs or not living up
23034
16:41:17,220 --> 16:41:18,220
to its full potential
23035
16:41:18,900 --> 16:41:19,900
so an application that needs bandwidth
23036
16:41:21,416 --> 16:41:22,416
because of its Effectiveness is impacted
23037
16:41:24,180 --> 16:41:25,180
by lag time for example applications
23038
16:41:26,456 --> 16:41:27,456
that use VoIP fall into this category or
23039
16:41:29,340 --> 16:41:30,340
voice over IP they're latency sensitive
23040
16:41:31,796 --> 16:41:32,796
because lag time could disrupt a video
23041
16:41:34,140 --> 16:41:35,140
or a phone call latency insensitive
23042
16:41:37,320 --> 16:41:38,320
applications still require bandwidth but
23043
16:41:39,540 --> 16:41:40,540
for a very different reason these don't
23044
16:41:41,340 --> 16:41:42,340
have video or voice transfer so the
23045
16:41:44,040 --> 16:41:45,040
bandwidth is just as important to them
23046
16:41:46,680 --> 16:41:47,680
but the latency doesn't really matter
23047
16:41:49,400 --> 16:41:50,400
these applications are those that are
23048
16:41:51,480 --> 16:41:52,480
used to transfer large amount of data
23049
16:41:53,220 --> 16:41:54,220
like during backup or FTP
23050
16:41:56,400 --> 16:41:57,400
just to cover this one more time and
23051
16:41:58,680 --> 16:41:59,680
perhaps say it in a different way
23052
16:41:59,756 --> 16:42:00,756
latency sensitive would be meaning that
23053
16:42:02,640 --> 16:42:03,640
if something for some reason I have a
23054
16:42:04,916 --> 16:42:05,916
huge uh amount of traffic then I'm going
23055
16:42:08,160 --> 16:42:09,160
to start seeing a degradation in service
23056
16:42:10,256 --> 16:42:11,256
when it comes to my latency sensitive
23057
16:42:12,900 --> 16:42:13,900
applications such as VoIP for instance I
23058
16:42:15,416 --> 16:42:16,416
need to make sure that no matter when
23059
16:42:17,340 --> 16:42:18,340
I'm talking over my VoIP phone it's
23060
16:42:20,160 --> 16:42:21,160
still reaching the end person in the
23061
16:42:22,436 --> 16:42:23,436
same degree of quality it can't be
23062
16:42:24,480 --> 16:42:25,480
dropping a lot of packets because if it
23063
16:42:26,220 --> 16:42:27,220
is then they're not going to be able to
23064
16:42:27,360 --> 16:42:28,360
hear my voice very clearly with latency
23065
16:42:29,700 --> 16:42:30,700
insensitive the traffic can modulate
23066
16:42:32,160 --> 16:42:33,160
quite a degree because as long as the
23067
16:42:34,616 --> 16:42:35,616
files get from one end to the other if
23068
16:42:36,720 --> 16:42:37,720
at one point it's transferring at 90
23069
16:42:38,756 --> 16:42:39,756
megabits per second and the next the
23070
16:42:40,320 --> 16:42:41,320
transmit one gigabit per second it's
23071
16:42:42,240 --> 16:42:43,240
still going to get over to the other
23072
16:42:44,276 --> 16:42:45,276
place but it doesn't really matter if I
23073
16:42:46,200 --> 16:42:47,200
don't receive the packets in a sort of
23074
16:42:48,000 --> 16:42:49,000
steady stream so in this case the
23075
16:42:50,520 --> 16:42:51,520
latency doesn't really matter as much as
23076
16:42:52,560 --> 16:42:53,560
the fact that it simply gets from one
23077
16:42:54,116 --> 16:42:55,116
place to the other it within a certain
23078
16:42:56,040 --> 16:42:57,040
degree of time
23079
16:42:57,480 --> 16:42:58,480
so a very important qos strategy to help
23080
16:43:01,740 --> 16:43:02,740
exist to help control the flow of data
23081
16:43:05,340 --> 16:43:06,340
through a network is called traffic
23082
16:43:07,320 --> 16:43:08,320
shaping
23083
16:43:08,520 --> 16:43:09,520
its main purpose is to reduce latency
23084
16:43:11,220 --> 16:43:12,220
which it does by controlling the amount
23085
16:43:13,380 --> 16:43:14,380
of data passing through a network data
23086
16:43:15,900 --> 16:43:16,900
traffic is sort of split into different
23087
16:43:17,936 --> 16:43:18,936
categories and put put in something
23088
16:43:20,040 --> 16:43:21,040
called a queue a queue by the way would
23089
16:43:23,520 --> 16:43:24,520
be something like a line basically I'm
23090
16:43:26,520 --> 16:43:27,520
going to put certain types of
23091
16:43:27,956 --> 16:43:28,956
information into one queue and certain
23092
16:43:30,000 --> 16:43:31,000
it to another and those cues are going
23093
16:43:32,220 --> 16:43:33,220
to be given priority
23094
16:43:34,020 --> 16:43:35,020
so my voice application is going to have
23095
16:43:36,060 --> 16:43:37,060
the highest priority whereas maybe my
23096
16:43:38,400 --> 16:43:39,400
FTP will have a bit of a lower priority
23097
16:43:40,980 --> 16:43:41,980
now there are quite a few different ways
23098
16:43:43,320 --> 16:43:44,320
to use traffic shaping and each method
23099
16:43:45,416 --> 16:43:46,416
has its own benefit and needs to be
23100
16:43:47,456 --> 16:43:48,456
chosen based on the circumstances of the
23101
16:43:50,096 --> 16:43:51,096
situation now here are a couple of the
23102
16:43:52,500 --> 16:43:53,500
common methods actually three
23103
16:43:55,020 --> 16:43:56,020
first is shaping by application
23104
16:43:57,840 --> 16:43:58,840
this is a strategy that involves the
23105
16:43:59,756 --> 16:44:00,756
administrator allowing only a certain
23106
16:44:01,916 --> 16:44:02,916
amount of bandwidth to be used by a
23107
16:44:03,776 --> 16:44:04,776
certain application for instance an
23108
16:44:05,880 --> 16:44:06,880
admin only allows a VoIP application to
23109
16:44:09,240 --> 16:44:10,240
use for instance six megabits per second
23110
16:44:11,580 --> 16:44:12,580
and it can't use any more than that so
23111
16:44:13,916 --> 16:44:14,916
in some ways we set a limit
23112
16:44:17,400 --> 16:44:18,400
to the bandwidth that's going to be used
23113
16:44:20,700 --> 16:44:21,700
by a certain protocol or a certain
23114
16:44:22,916 --> 16:44:23,916
application
23115
16:44:24,116 --> 16:44:25,116
the next which is called shaping Network
23116
16:44:26,936 --> 16:44:27,936
traffic per user allows the
23117
16:44:29,276 --> 16:44:30,276
administrator to limit the bandwidth
23118
16:44:30,660 --> 16:44:31,660
that any individual user can use now
23119
16:44:33,116 --> 16:44:34,116
shaving by application is something that
23120
16:44:34,916 --> 16:44:35,916
we're going to be seeing a lot now on
23121
16:44:36,720 --> 16:44:37,720
airplanes and trains we don't want to
23122
16:44:39,776 --> 16:44:40,776
let for instance people use Netflix and
23123
16:44:42,900 --> 16:44:43,900
YouTube on the plane because there are
23124
16:44:44,456 --> 16:44:45,456
other people who need to be using email
23125
16:44:45,720 --> 16:44:46,720
and so we're just going to say if you
23126
16:44:47,520 --> 16:44:48,520
want to do bandwidth for video we're not
23127
16:44:49,680 --> 16:44:50,680
going to allow that as much as bandwidth
23128
16:44:51,720 --> 16:44:52,720
for say
23129
16:44:53,000 --> 16:44:54,000
email or for text messaging for instance
23130
16:44:57,060 --> 16:44:58,060
but when I'm talking about Network
23131
16:44:59,040 --> 16:45:00,040
traffic per user I'm allowing specific
23132
16:45:01,916 --> 16:45:02,916
users to have a certain amount of
23133
16:45:03,360 --> 16:45:04,360
bandwidth so some users might use more
23134
16:45:05,456 --> 16:45:06,456
bandwidth than others and sometimes it
23135
16:45:07,020 --> 16:45:08,020
isn't all for work reasons for instance
23136
16:45:09,060 --> 16:45:10,060
let's say that Anthony from sales is
23137
16:45:10,680 --> 16:45:11,680
constantly streaming video or audio to
23138
16:45:12,296 --> 16:45:13,296
his computer this is using a lot of
23139
16:45:14,096 --> 16:45:15,096
bandwidth so now the discipline part of
23140
16:45:16,080 --> 16:45:17,080
this may not be up to the administrator
23141
16:45:17,936 --> 16:45:18,936
but he or she can certainly limit the
23142
16:45:20,580 --> 16:45:21,580
amount of bandwidth Anthony is allowed
23143
16:45:22,256 --> 16:45:23,256
to use so if each and visual for
23144
16:45:25,560 --> 16:45:26,560
instance Anthony is limited to 256
23145
16:45:27,956 --> 16:45:28,956
kilobits per second it's not going to
23146
16:45:30,000 --> 16:45:31,000
access what he can access just how fast
23147
16:45:32,456 --> 16:45:33,456
he's able to access it so whereas this
23148
16:45:34,740 --> 16:45:35,740
is really doing it shipping by
23149
16:45:36,116 --> 16:45:37,116
application based on the type of
23150
16:45:37,796 --> 16:45:38,796
information shaping the network traffic
23151
16:45:39,720 --> 16:45:40,720
per user
23152
16:45:41,096 --> 16:45:42,096
is on an individual basis and this way I
23153
16:45:44,040 --> 16:45:45,040
can give each user
23154
16:45:46,560 --> 16:45:47,560
let's say Anthony Maria
23155
16:45:51,200 --> 16:45:52,200
Amy each a certain degree
23156
16:45:55,200 --> 16:45:56,200
of bandwidth
23157
16:45:58,500 --> 16:45:59,500
so that no person can use one more than
23158
16:46:01,020 --> 16:46:02,020
the other of course a downside with this
23159
16:46:03,060 --> 16:46:04,060
is if Amy's only using let's say 10
23160
16:46:05,580 --> 16:46:06,580
kilobits per second to send emails and
23161
16:46:08,580 --> 16:46:09,580
Maria is on the video team and is trying
23162
16:46:11,820 --> 16:46:12,820
to use all of her 256 she might be able
23163
16:46:15,480 --> 16:46:16,480
to use some of Amy's but because of the
23164
16:46:16,980 --> 16:46:17,980
way we've shaped this per user Marie
23165
16:46:19,320 --> 16:46:20,320
doesn't get any more and sometimes what
23166
16:46:21,360 --> 16:46:22,360
we'll do is give people in certain roles
23167
16:46:24,000 --> 16:46:25,000
the company a little more traffic or
23168
16:46:26,880 --> 16:46:27,880
bandwidth allowability than some of the
23169
16:46:29,096 --> 16:46:30,096
others for instance accounting probably
23170
16:46:30,596 --> 16:46:31,596
doesn't need as much as our Graphics
23171
16:46:32,820 --> 16:46:33,820
team
23172
16:46:33,776 --> 16:46:34,776
finally we have something called
23173
16:46:35,340 --> 16:46:36,340
priority shaping which is the way to
23174
16:46:37,740 --> 16:46:38,740
allow more bandwidth to to those who
23175
16:46:39,596 --> 16:46:40,596
require it most sort of what I'm
23176
16:46:41,160 --> 16:46:42,160
referring to
23177
16:46:42,296 --> 16:46:43,296
here for example in a school system the
23178
16:46:44,640 --> 16:46:45,640
teachers need more bandwidth in the
23179
16:46:46,140 --> 16:46:47,140
students so the network admin shapes the
23180
16:46:48,416 --> 16:46:49,416
traffic again we have that great term
23181
16:46:50,700 --> 16:46:51,700
priority shaping so that it's dedicated
23182
16:46:53,520 --> 16:46:54,520
more to the teachers but the students
23183
16:46:55,200 --> 16:46:56,200
can still use it at a slower speed so
23184
16:46:57,240 --> 16:46:58,240
when the teachers don't need the
23185
16:46:58,680 --> 16:46:59,680
bandwidth the students are able to
23186
16:47:00,296 --> 16:47:01,296
access it at faster speeds so we're
23187
16:47:02,276 --> 16:47:03,276
really taking this sort of concept
23188
16:47:05,756 --> 16:47:06,756
and allowing it to be a little more
23189
16:47:07,860 --> 16:47:08,860
flexible
23190
16:47:11,520 --> 16:47:12,520
now another technique used is something
23191
16:47:13,200 --> 16:47:14,200
called a caching engine
23192
16:47:15,060 --> 16:47:16,060
caching is essentially temporary storage
23193
16:47:17,700 --> 16:47:18,700
although the storing of what is changing
23194
16:47:20,880 --> 16:47:21,880
every single time
23195
16:47:22,320 --> 16:47:23,320
in the case of caching engines the
23196
16:47:25,680 --> 16:47:26,680
temporarily storage of data is actually
23197
16:47:28,080 --> 16:47:29,080
web data that can be used in the future
23198
16:47:30,180 --> 16:47:31,180
so this is happening through something
23199
16:47:32,220 --> 16:47:33,220
called a proxy server
23200
16:47:36,680 --> 16:47:37,680
basically what's happening is without
23201
16:47:39,416 --> 16:47:40,416
going too far in depth into it is that a
23202
16:47:41,756 --> 16:47:42,756
proxy server caches web data for future
23203
16:47:43,980 --> 16:47:44,980
uses by others so if I have let's say
23204
16:47:47,580 --> 16:47:48,580
three users
23205
16:47:49,616 --> 16:47:50,616
and the first user and I have a proxy
23206
16:47:52,796 --> 16:47:53,796
server in between them before it goes
23207
16:47:55,860 --> 16:47:56,860
out to the internet
23208
16:48:00,540 --> 16:48:01,540
and the first user requests
23209
16:48:03,776 --> 16:48:04,776
CNN
23210
16:48:05,220 --> 16:48:06,220
the proxy server which holds a cache
23211
16:48:08,700 --> 16:48:09,700
or sort of copies of everything
23212
16:48:11,340 --> 16:48:12,340
we'll first say hey I have the latest
23213
16:48:13,256 --> 16:48:14,256
CNN or I don't have the latest CNN it'll
23214
16:48:15,720 --> 16:48:16,720
then go out to the internet
23215
16:48:17,640 --> 16:48:18,640
get the latest CNN
23216
16:48:21,660 --> 16:48:22,660
and hold that
23217
16:48:24,116 --> 16:48:25,116
in its proxy now when the second user
23218
16:48:26,936 --> 16:48:27,936
five seconds later says Hey I want the
23219
16:48:29,456 --> 16:48:30,456
latest CNN the proxy server does not
23220
16:48:31,560 --> 16:48:32,560
have to go out to the internet we can
23221
16:48:33,296 --> 16:48:34,296
basically cut out this entire process
23222
16:48:36,596 --> 16:48:37,596
and instead it just Returns what it is
23223
16:48:39,416 --> 16:48:40,416
already cached it can do this with as
23224
16:48:41,640 --> 16:48:42,640
many uses as possible and what we'll
23225
16:48:43,500 --> 16:48:44,500
generally say is that every minute or
23226
16:48:46,200 --> 16:48:47,200
every few seconds it's going to update
23227
16:48:48,240 --> 16:48:49,240
the proxy server is going to update its
23228
16:48:49,916 --> 16:48:50,916
information that way we can make sure
23229
16:48:51,360 --> 16:48:52,360
that it's still the most up-to-date
23230
16:48:52,740 --> 16:48:53,740
information which is one of the
23231
16:48:54,540 --> 16:48:55,540
downsides of using proxy servers and
23232
16:48:56,400 --> 16:48:57,400
caching is that sometimes
23233
16:48:59,096 --> 16:49:00,096
um it's not going to have the most
23234
16:49:00,360 --> 16:49:01,360
up-to-date information but it certainly
23235
16:49:02,160 --> 16:49:03,160
speeds things up by cutting out this
23236
16:49:04,140 --> 16:49:05,140
whole process of having to go out to the
23237
16:49:05,456 --> 16:49:06,456
Internet by keeping it locally
23238
16:49:07,740 --> 16:49:08,740
now this all saves bandwidth because
23239
16:49:10,860 --> 16:49:11,860
obviously I'm not having to go out to
23240
16:49:12,596 --> 16:49:13,596
the internet and therefore I can reserve
23241
16:49:14,756 --> 16:49:15,756
that bandwidth speed that would have
23242
16:49:16,616 --> 16:49:17,616
been used for video or something else
23243
16:49:18,840 --> 16:49:19,840
that's new uh instead of having to use
23244
16:49:21,180 --> 16:49:22,180
it for information that I'm gathering
23245
16:49:22,740 --> 16:49:23,740
over and over and over again you can
23246
16:49:25,020 --> 16:49:26,020
imagine in a corporation of thousands or
23247
16:49:27,116 --> 16:49:28,116
hundreds of thousands of people this is
23248
16:49:28,740 --> 16:49:29,740
really going to save us a lot of time
23249
16:49:32,456 --> 16:49:33,456
all right so just to recap we talked
23250
16:49:34,680 --> 16:49:35,680
about Network optimization there were a
23251
16:49:36,596 --> 16:49:37,596
couple terms we mentioned first was
23252
16:49:38,520 --> 16:49:39,520
bandwidth bandwidth is the highest
23253
16:49:41,040 --> 16:49:42,040
possible speed that we have on our data
23254
16:49:43,380 --> 16:49:44,380
connection we also talked about
23255
16:49:45,000 --> 16:49:46,000
something called throughput whereas
23256
16:49:47,400 --> 16:49:48,400
bandwidth
23257
16:49:48,900 --> 16:49:49,900
is the ideal or potential
23258
16:49:52,320 --> 16:49:53,320
speed
23259
16:49:54,540 --> 16:49:55,540
throughput
23260
16:49:56,220 --> 16:49:57,220
is the actual speed how much is actually
23261
16:49:58,616 --> 16:49:59,616
traveling and what we want to do is get
23262
16:50:01,436 --> 16:50:02,436
these two to equal one another as much
23263
16:50:03,416 --> 16:50:04,416
as possible however we also want to make
23264
16:50:06,116 --> 16:50:07,116
sure to make good use of our bandwidth
23265
16:50:08,400 --> 16:50:09,400
so that everyone can get information
23266
16:50:10,080 --> 16:50:11,080
they need when they need it so then we
23267
16:50:12,360 --> 16:50:13,360
talked about something called quality of
23268
16:50:14,160 --> 16:50:15,160
service quality of service make sure
23269
16:50:16,500 --> 16:50:17,500
that we're using our bandwidth in a way
23270
16:50:19,080 --> 16:50:20,080
that's going to promote good quality we
23271
16:50:21,596 --> 16:50:22,596
talked about two different types of
23272
16:50:22,980 --> 16:50:23,980
applications in ways that we use quality
23273
16:50:25,560 --> 16:50:26,560
of service first we look at latency
23274
16:50:27,296 --> 16:50:28,296
sensitive applications these are the
23275
16:50:28,980 --> 16:50:29,980
applications that where there is latency
23276
16:50:31,320 --> 16:50:32,320
or
23277
16:50:32,756 --> 16:50:33,756
another word for this might be traffic
23278
16:50:36,000 --> 16:50:37,000
it's going to reduce the speed on the
23279
16:50:37,616 --> 16:50:38,616
network the quality of the service is
23280
16:50:40,436 --> 16:50:41,436
going to start degrading so voice over
23281
16:50:42,360 --> 16:50:43,360
IP is a great example of this if there's
23282
16:50:44,340 --> 16:50:45,340
a lot of things going on in the network
23283
16:50:45,900 --> 16:50:46,900
then our voice over IP isn't going to
23284
16:50:48,776 --> 16:50:49,776
work as effectively and then I can't
23285
16:50:50,640 --> 16:50:51,640
count on voice over IP as a good
23286
16:50:52,380 --> 16:50:53,380
technology so it's important that I make
23287
16:50:54,480 --> 16:50:55,480
sure Voiceover IP always has a certain
23288
16:50:57,116 --> 16:50:58,116
degree of say bandwidth with latency
23289
16:51:00,540 --> 16:51:01,540
insensitive applications we're looking
23290
16:51:02,400 --> 16:51:03,400
at stuff where the speed although it
23291
16:51:04,796 --> 16:51:05,796
still needs to be fast doesn't matter if
23292
16:51:06,360 --> 16:51:07,360
there's latency one second and no
23293
16:51:07,796 --> 16:51:08,796
latency the next when we're transferring
23294
16:51:09,956 --> 16:51:10,956
high high or large files such as through
23295
16:51:13,740 --> 16:51:14,740
FTP then we don't need to make sure that
23296
16:51:16,740 --> 16:51:17,740
we're not modulating between 90 kilobits
23297
16:51:18,596 --> 16:51:19,596
per second and 90 megabits per second or
23298
16:51:20,220 --> 16:51:21,220
one gigabit per second as long as the
23299
16:51:21,956 --> 16:51:22,956
data gets to where it needs to go
23300
16:51:24,000 --> 16:51:25,000
I don't need to make sure that it's
23301
16:51:25,860 --> 16:51:26,860
getting there at the exact time because
23302
16:51:27,596 --> 16:51:28,596
for instance with voice over IP if I'm
23303
16:51:29,936 --> 16:51:30,936
talking it needs to be able to reach the
23304
16:51:31,740 --> 16:51:32,740
person sort of the degree that I'm
23305
16:51:33,180 --> 16:51:34,180
talking but with FTP it doesn't really
23306
16:51:35,160 --> 16:51:36,160
matter if it's getting there in the same
23307
16:51:37,256 --> 16:51:38,256
instant
23308
16:51:38,220 --> 16:51:39,220
we also talked about traffic shaping
23309
16:51:40,380 --> 16:51:41,380
which is one of the ways that we use
23310
16:51:42,240 --> 16:51:43,240
quality of service and we shape
23311
16:51:44,580 --> 16:51:45,580
the bandwidth so that it is used in an
23312
16:51:48,240 --> 16:51:49,240
appropriate way we talked about three
23313
16:51:50,340 --> 16:51:51,340
different ways of doing this
23314
16:51:52,500 --> 16:51:53,500
the first we talked about was based on
23315
16:51:55,020 --> 16:51:56,020
application so for instance I'm going to
23316
16:51:57,660 --> 16:51:58,660
give a certain degree of bandwidth to
23317
16:52:00,116 --> 16:52:01,116
one application and a certain to another
23318
16:52:02,240 --> 16:52:03,240
once all the voice over IP bandwidth is
23319
16:52:05,520 --> 16:52:06,520
used that's it once all the FTP
23320
16:52:08,096 --> 16:52:09,096
bandwidth is used I don't have any more
23321
16:52:10,320 --> 16:52:11,320
and so I'm only giving if I have a large
23322
16:52:12,840 --> 16:52:13,840
bandwidth let's say this box represents
23323
16:52:14,700 --> 16:52:15,700
bandwidth
23324
16:52:16,200 --> 16:52:17,200
then I'm going to sort of divide this
23325
16:52:18,776 --> 16:52:19,776
into layers
23326
16:52:20,160 --> 16:52:21,160
so FTP gets some
23327
16:52:22,880 --> 16:52:23,880
HTTP gets some voice over IP gets some
23328
16:52:26,520 --> 16:52:27,520
Etc
23329
16:52:27,480 --> 16:52:28,480
we also talked about user specific
23330
16:52:30,116 --> 16:52:31,116
which means that instead of dividing
23331
16:52:32,096 --> 16:52:33,096
things up
23332
16:52:33,180 --> 16:52:34,180
based on the application I'm going to
23333
16:52:36,116 --> 16:52:37,116
divide it up based on the individual
23334
16:52:38,340 --> 16:52:39,340
so Maria gets a certain amount
23335
16:52:41,340 --> 16:52:42,340
Anthony gets a certain amount
23336
16:52:44,040 --> 16:52:45,040
and Amy gets a certain amount
23337
16:52:46,140 --> 16:52:47,140
finally we looked at priority shaping
23338
16:52:49,616 --> 16:52:50,616
which is a really cool term
23339
16:52:52,980 --> 16:52:53,980
and what this means is I can give
23340
16:52:54,900 --> 16:52:55,900
certain priority to certain individuals
23341
16:52:57,180 --> 16:52:58,180
or groups so for instance we use the
23342
16:53:00,296 --> 16:53:01,296
teachers versus students comparison
23343
16:53:02,756 --> 16:53:03,756
teachers we want to have a lot more than
23344
16:53:05,340 --> 16:53:06,340
the students so students get a very
23345
16:53:07,380 --> 16:53:08,380
small amount whereas teachers get a very
23346
16:53:09,240 --> 16:53:10,240
large amount same with on a corporate
23347
16:53:11,340 --> 16:53:12,340
Network perhaps I want a management or
23348
16:53:13,500 --> 16:53:14,500
my Graphics team to have a lot more than
23349
16:53:15,840 --> 16:53:16,840
say my accounting team or lower
23350
16:53:17,640 --> 16:53:18,640
management or the secretaries finally we
23351
16:53:20,400 --> 16:53:21,400
talked about caching engines and we use
23352
16:53:22,436 --> 16:53:23,436
the word proxy server this is going to
23353
16:53:25,080 --> 16:53:26,080
save us time because whenever I go out
23354
16:53:27,540 --> 16:53:28,540
to get information from a website I
23355
16:53:29,580 --> 16:53:30,580
don't have to go get the information
23356
16:53:30,776 --> 16:53:31,776
fresh every time instead I'm going to
23357
16:53:33,776 --> 16:53:34,776
use the proxy server to hold a copy or a
23358
16:53:37,616 --> 16:53:38,616
cached version of my website and that
23359
16:53:41,040 --> 16:53:42,040
way I don't have to go out to the
23360
16:53:42,116 --> 16:53:43,116
internet every time and I can reserve
23361
16:53:43,680 --> 16:53:44,680
that bandwidth for other things I might
23362
16:53:45,416 --> 16:53:46,416
need to use
23363
16:53:49,600 --> 16:53:50,600
[Music]
23364
16:53:58,220 --> 16:53:59,220
thank you
23365
16:54:05,580 --> 16:54:06,580
okay welcome to module 11 lesson 3
23366
16:54:07,860 --> 16:54:08,860
Network documentation a little bit um of
23367
16:54:11,880 --> 16:54:12,880
a harder on this it's just a bit
23368
16:54:14,040 --> 16:54:15,040
easier Terry can wishy-washy
23369
16:54:16,560 --> 16:54:17,560
um although it's obviously important
23370
16:54:18,720 --> 16:54:19,720
but just to discuss and what is it I'm
23371
16:54:21,596 --> 16:54:22,596
sure you could actually work out well
23372
16:54:22,860 --> 16:54:23,860
one network documentation is why do we
23373
16:54:25,860 --> 16:54:26,860
why do we have it importance of it
23374
16:54:28,916 --> 16:54:29,916
parts of it
23375
16:54:30,776 --> 16:54:31,776
and many General assets and our Network
23376
16:54:32,820 --> 16:54:33,820
diagrams
23377
16:54:34,400 --> 16:54:35,400
RFID which we go into
23378
16:54:37,400 --> 16:54:38,400
tracking our IP address utilization
23379
16:54:39,776 --> 16:54:40,776
which is quite a handy thing to have
23380
16:54:41,400 --> 16:54:42,400
actually information about vendors and
23381
16:54:43,916 --> 16:54:44,916
contractors and all of our policies and
23382
16:54:46,256 --> 16:54:47,256
procedures
23383
16:54:48,416 --> 16:54:49,416
so the whole principle behind Network
23384
16:54:50,596 --> 16:54:51,596
documentation is professionalism really
23385
16:54:52,980 --> 16:54:53,980
and business continuity and it's um an
23386
16:54:55,980 --> 16:54:56,980
emerging field
23387
16:54:57,840 --> 16:54:58,840
and in the world of I.T non-technical
23388
16:55:00,660 --> 16:55:01,660
but looking at audit trails and um yeah
23389
16:55:05,400 --> 16:55:06,400
in the context of documentation really
23390
16:55:07,320 --> 16:55:08,320
and all of our procedures
23391
16:55:10,980 --> 16:55:11,980
so critical role and especially when
23392
16:55:13,740 --> 16:55:14,740
there's a problem because people start
23393
16:55:15,360 --> 16:55:16,360
scrambling looking for what to do in
23394
16:55:18,596 --> 16:55:19,596
terms of procedures and policies who
23395
16:55:21,060 --> 16:55:22,060
does what
23396
16:55:22,860 --> 16:55:23,860
um where to find them how to contact
23397
16:55:24,540 --> 16:55:25,540
them and
23398
16:55:26,700 --> 16:55:27,700
um where the technology is and how to
23399
16:55:28,560 --> 16:55:29,560
fix here there's a whole bunch of
23400
16:55:30,020 --> 16:55:31,020
procedures and documents that have to
23401
16:55:32,820 --> 16:55:33,820
all be easily accessible and come
23402
16:55:34,860 --> 16:55:35,860
together and bear in mind that um the
23403
16:55:37,616 --> 16:55:38,616
network could be down there could be an
23404
16:55:39,240 --> 16:55:40,240
outage so if it's contained on a service
23405
16:55:41,400 --> 16:55:42,400
somewhere then that might not be um
23406
16:55:43,860 --> 16:55:44,860
ideal if it's only kept on the server
23407
16:55:46,140 --> 16:55:47,140
anyway
23408
16:55:47,340 --> 16:55:48,340
so um you can't remember everything
23409
16:55:49,320 --> 16:55:50,320
especially if it's a large Network or
23410
16:55:51,540 --> 16:55:52,540
even worse if it's a small company and
23411
16:55:54,000 --> 16:55:55,000
somebody leaves the business and you
23412
16:55:56,096 --> 16:55:57,096
take over from them if there's no
23413
16:55:57,596 --> 16:55:58,596
documentation then it causes a lot of
23414
16:55:59,580 --> 16:56:00,580
Heartache
23415
16:56:02,756 --> 16:56:03,756
um and yeah if you're the one to have
23416
16:56:04,916 --> 16:56:05,916
joined it's um it's pretty difficult
23417
16:56:06,660 --> 16:56:07,660
because you've got to learn the network
23418
16:56:07,680 --> 16:56:08,680
from scratch
23419
16:56:10,140 --> 16:56:11,140
and it's not possible to go and search a
23420
16:56:12,000 --> 16:56:13,000
network organization administrators
23421
16:56:13,740 --> 16:56:14,740
who've quit
23422
16:56:15,360 --> 16:56:16,360
don't believe they have their phones
23423
16:56:16,740 --> 16:56:17,740
taken off them or they're just going a
23424
16:56:18,116 --> 16:56:19,116
long vacation so you don't got to find
23425
16:56:19,616 --> 16:56:20,616
them
23426
16:56:21,000 --> 16:56:22,000
so it gives Network administrators
23427
16:56:23,456 --> 16:56:24,456
information about the network appearance
23428
16:56:26,640 --> 16:56:27,640
logical versus physical
23429
16:56:28,456 --> 16:56:29,456
baselines how it's performing I should
23430
16:56:30,720 --> 16:56:31,720
perform to see if there's anything
23431
16:56:32,820 --> 16:56:33,820
um out of the ordinary
23432
16:56:34,740 --> 16:56:35,740
um where to begin troubleshooting
23433
16:56:36,956 --> 16:56:37,956
so the main purpose is to keep the
23434
16:56:38,756 --> 16:56:39,756
network running smoothly so we've got
23435
16:56:40,256 --> 16:56:41,256
that five nines
23436
16:56:41,840 --> 16:56:42,840
99.99 uptime ideally
23437
16:56:45,540 --> 16:56:46,540
it's important to maintain the
23438
16:56:47,040 --> 16:56:48,040
documentation and keep it while
23439
16:56:49,380 --> 16:56:50,380
maintaining means keep it up to date
23440
16:56:51,060 --> 16:56:52,060
because out of date documentation
23441
16:56:53,276 --> 16:56:54,276
actually causes more problems than it
23442
16:56:55,080 --> 16:56:56,080
fixes because all of a sudden you're
23443
16:56:56,756 --> 16:56:57,756
looking at the wrong devices or the
23444
16:56:58,256 --> 16:56:59,256
wrong ports or the wrong IP addresses
23445
16:56:59,936 --> 16:57:00,936
and I've been there
23446
16:57:03,116 --> 16:57:04,116
um so yeah that's what I've said
23447
16:57:04,380 --> 16:57:05,380
essential Parts include Network diagrams
23448
16:57:06,416 --> 16:57:07,416
Asset Management IP address utilization
23449
16:57:09,416 --> 16:57:10,416
you could have more or less depending on
23450
16:57:11,700 --> 16:57:12,700
your organization and the size of it you
23451
16:57:14,340 --> 16:57:15,340
did information about the vendors and
23452
16:57:16,200 --> 16:57:17,200
contractors procedures and policies who
23453
16:57:19,796 --> 16:57:20,796
should be doing what and when and also
23454
16:57:22,140 --> 16:57:23,140
logical and
23455
16:57:24,060 --> 16:57:25,060
um physical this is a
23456
16:57:28,020 --> 16:57:29,020
a topology diagram of all the hardware
23457
16:57:30,956 --> 16:57:31,956
and the connections we haven't named the
23458
16:57:33,000 --> 16:57:34,000
ports on this particular diagram it's
23459
16:57:35,220 --> 16:57:36,220
copyright as Scott McDonald
23460
16:57:37,796 --> 16:57:38,796
uh just to give you an idea this looks
23461
16:57:39,720 --> 16:57:40,720
like it was done in Vizio which is a
23462
16:57:41,756 --> 16:57:42,756
Cisco Network creation
23463
16:57:44,400 --> 16:57:45,400
um diagramming tool there's others out
23464
16:57:46,320 --> 16:57:47,320
there it's a free to troll or some are
23465
16:57:48,720 --> 16:57:49,720
free to use
23466
16:57:50,096 --> 16:57:51,096
and it shows you all your different
23467
16:57:51,540 --> 16:57:52,540
devices
23468
16:57:53,580 --> 16:57:54,580
The Logical provides the logical view of
23469
16:57:56,220 --> 16:57:57,220
how the network sees itself not how we
23470
16:57:58,796 --> 16:57:59,796
will physically see the network in the
23471
16:58:00,416 --> 16:58:01,416
server room
23472
16:58:02,700 --> 16:58:03,700
uh indicates how the traffic flows
23473
16:58:04,680 --> 16:58:05,680
between devices in the network so you'll
23474
16:58:06,596 --> 16:58:07,596
see all of your vlans routing
23475
16:58:09,020 --> 16:58:10,020
redistribution all these kind of things
23476
16:58:11,580 --> 16:58:12,580
bgp if you have it
23477
16:58:14,040 --> 16:58:15,040
a logical net Network diagrams include
23478
16:58:16,796 --> 16:58:17,796
domain names IP addresses and the tasks
23479
16:58:19,796 --> 16:58:20,796
performed by each different device
23480
16:58:22,796 --> 16:58:23,796
logically includes how devices
23481
16:58:25,500 --> 16:58:26,500
communicate with each other which
23482
16:58:27,540 --> 16:58:28,540
direction the traffic flows
23483
16:58:30,060 --> 16:58:31,060
and how all these devices work together
23484
16:58:33,240 --> 16:58:34,240
the physical network shows the actual
23485
16:58:35,160 --> 16:58:36,160
physical connection so you can look at
23486
16:58:36,840 --> 16:58:37,840
the diagram of a certain router and you
23487
16:58:39,720 --> 16:58:40,720
can see which ports
23488
16:58:41,580 --> 16:58:42,580
are on the router how many and what it's
23489
16:58:44,040 --> 16:58:45,040
actually physically connected to and a
23490
16:58:46,916 --> 16:58:47,916
lot of companies use the concept of
23491
16:58:48,296 --> 16:58:49,296
remote hands so you can use these
23492
16:58:50,520 --> 16:58:51,520
diagrams to tell the remote hands where
23493
16:58:52,860 --> 16:58:53,860
to find the device and which cable to
23494
16:58:55,500 --> 16:58:56,500
plug unplug Etc
23495
16:58:59,900 --> 16:59:00,900
physical network is the physical layout
23496
16:59:02,520 --> 16:59:03,520
that I've mentioned so here's a typical
23497
16:59:06,240 --> 16:59:07,240
diagram above is the physical topology
23498
16:59:08,880 --> 16:59:09,880
and below is logical topology
23499
16:59:12,180 --> 16:59:13,180
so you might not necessarily see all of
23500
16:59:15,416 --> 16:59:16,416
the hardware devices you're going to see
23501
16:59:17,040 --> 16:59:18,040
things like vlans connections going out
23502
16:59:19,020 --> 16:59:20,020
to isps
23503
16:59:20,756 --> 16:59:21,756
and hot standby routing protocol all
23504
16:59:23,700 --> 16:59:24,700
this kind of thing
23505
16:59:24,956 --> 16:59:25,956
uh you won't generally see end devices
23506
16:59:27,296 --> 16:59:28,296
on the topology diagram so this is a
23507
16:59:30,116 --> 16:59:31,116
very small Network or unless one of the
23508
16:59:32,160 --> 16:59:33,160
end devices happens to be your network
23509
16:59:34,380 --> 16:59:35,380
management server or something like that
23510
16:59:38,520 --> 16:59:39,520
so your documentation should include
23511
16:59:40,796 --> 16:59:41,796
notes about Asset Management a whole
23512
16:59:43,860 --> 16:59:44,860
bunch of things name model number
23513
16:59:45,540 --> 16:59:46,540
manufacturer data purchase a version of
23514
16:59:48,660 --> 16:59:49,660
software running does it need updating
23515
16:59:50,660 --> 16:59:51,660
is there problems of that particular
23516
16:59:53,096 --> 16:59:54,096
release of software updates location
23517
16:59:56,160 --> 16:59:57,160
warranty and who has it who's
23518
16:59:57,840 --> 16:59:58,840
responsible for it if you're sitting
23519
16:59:59,880 --> 17:00:00,880
under some under somebody's desk and
23520
17:00:01,860 --> 17:00:02,860
nobody knows and it doesn't serve any
23521
17:00:03,360 --> 17:00:04,360
purpose
23522
17:00:04,500 --> 17:00:05,500
so you should keep track of all your
23523
17:00:06,480 --> 17:00:07,480
assets and eventually there's normally a
23524
17:00:08,880 --> 17:00:09,880
disposal
23525
17:00:09,900 --> 17:00:10,900
a procedure as well where the devices
23526
17:00:11,756 --> 17:00:12,756
are wiped and fragmented defragmented
23527
17:00:16,560 --> 17:00:17,560
whatever and whatever type of um
23528
17:00:20,640 --> 17:00:21,640
scrubbing is done on their drives if
23529
17:00:22,616 --> 17:00:23,616
necessary so there's no data that's
23530
17:00:24,840 --> 17:00:25,840
important devices are tagged with the
23531
17:00:27,956 --> 17:00:28,956
barcodes or RFID is an example of one
23532
17:00:31,200 --> 17:00:32,200
here these are normally read by little
23533
17:00:33,776 --> 17:00:34,776
um reader gun like you find in
23534
17:00:35,340 --> 17:00:36,340
supermarkets if it's been tagged with a
23535
17:00:37,680 --> 17:00:38,680
barcode a barcode scanner will help
23536
17:00:39,240 --> 17:00:40,240
retrieve information
23537
17:00:41,160 --> 17:00:42,160
and the RFID stands for radio frequency
23538
17:00:43,740 --> 17:00:44,740
ID tags that normally have electrically
23539
17:00:46,256 --> 17:00:47,256
stored information and the readers are
23540
17:00:48,840 --> 17:00:49,840
used to track devices this would
23541
17:00:50,520 --> 17:00:51,520
obviously be on a pretty big Network
23542
17:00:53,520 --> 17:00:54,520
um
23543
17:00:54,540 --> 17:00:55,540
yeah Network documentation should
23544
17:00:56,756 --> 17:00:57,756
include your IP address utilization
23545
17:00:58,796 --> 17:00:59,796
there's normally one or two people in
23546
17:01:01,500 --> 17:01:02,500
charge of allocating addresses or blocks
23547
17:01:04,020 --> 17:01:05,020
of addresses
23548
17:01:05,220 --> 17:01:06,220
because they're aware of which addresses
23549
17:01:07,740 --> 17:01:08,740
should be where which subnets and which
23550
17:01:10,080 --> 17:01:11,080
addresses are summarized
23551
17:01:12,240 --> 17:01:13,240
and this helps with all of our routing
23552
17:01:14,580 --> 17:01:15,580
updates I have seen problems in the in
23553
17:01:17,276 --> 17:01:18,276
the past and people should know better
23554
17:01:19,320 --> 17:01:20,320
in fact have manually allocated IP
23555
17:01:22,200 --> 17:01:23,200
addresses to their devices for whatever
23556
17:01:23,936 --> 17:01:24,936
reason and it's caused Network
23557
17:01:26,040 --> 17:01:27,040
instability
23558
17:01:27,900 --> 17:01:28,900
so Network administrators should keep
23559
17:01:29,580 --> 17:01:30,580
track of the number of IP addresses that
23560
17:01:31,320 --> 17:01:32,320
have been allocated to the network how
23561
17:01:33,480 --> 17:01:34,480
many have been in user it'll normally
23562
17:01:34,916 --> 17:01:35,916
Flagger pay alert if you're running
23563
17:01:36,776 --> 17:01:37,776
short
23564
17:01:38,340 --> 17:01:39,340
if a subnet grows the number of IP
23565
17:01:40,616 --> 17:01:41,616
addresses assigned to it you're likely
23566
17:01:42,416 --> 17:01:43,416
to have a problem
23567
17:01:44,640 --> 17:01:45,640
okay all important to keep uh you know
23568
17:01:47,340 --> 17:01:48,340
the utilization as I've said in case we
23569
17:01:49,200 --> 17:01:50,200
need to run out or buy some more order
23570
17:01:50,700 --> 17:01:51,700
them in advance
23571
17:01:51,956 --> 17:01:52,956
you should also have information about
23572
17:01:53,700 --> 17:01:54,700
vendors and contractors
23573
17:01:59,220 --> 17:02:00,220
that should include vendor names their
23574
17:02:01,436 --> 17:02:02,436
services the cost contact information we
23575
17:02:03,720 --> 17:02:04,720
normally get our point of contact and
23576
17:02:05,880 --> 17:02:06,880
the support hours
23577
17:02:07,500 --> 17:02:08,500
or should have um
23578
17:02:09,180 --> 17:02:10,180
documentation about all of our policies
23579
17:02:11,580 --> 17:02:12,580
and standards well worth looking into a
23580
17:02:14,276 --> 17:02:15,276
project management and also ITIL exams
23581
17:02:17,096 --> 17:02:18,096
so change management and managing all
23582
17:02:19,616 --> 17:02:20,616
your processes and procedures and
23583
17:02:21,900 --> 17:02:22,900
problems and on the network
23584
17:02:25,340 --> 17:02:26,340
uh provides for example the list of
23585
17:02:27,660 --> 17:02:28,660
people who should be contacted certainly
23586
17:02:29,580 --> 17:02:30,580
when I worked on a pretty large Network
23587
17:02:31,200 --> 17:02:32,200
there was a number of key people so you
23588
17:02:33,416 --> 17:02:34,416
have thousands in the organization that
23589
17:02:36,000 --> 17:02:37,000
you would contact four or five or six
23590
17:02:37,860 --> 17:02:38,860
key people and they would each have a
23591
17:02:40,680 --> 17:02:41,680
role of who's going to communicate to
23592
17:02:42,180 --> 17:02:43,180
who who's going to tell the boss and do
23593
17:02:45,240 --> 17:02:46,240
the does the press or other customers
23594
17:02:46,980 --> 17:02:47,980
need to be informed of what's going on
23595
17:02:49,080 --> 17:02:50,080
this is to stop uh confusion and also
23596
17:02:51,776 --> 17:02:52,776
track back as to who should have been
23597
17:02:53,520 --> 17:02:54,520
doing what
23598
17:02:55,080 --> 17:02:56,080
policies require compliance and in their
23599
17:02:57,480 --> 17:02:58,480
enforce discipline or disciplinary
23600
17:02:59,220 --> 17:03:00,220
actions or obviously training if a
23601
17:03:01,320 --> 17:03:02,320
person hasn't been given sufficient
23602
17:03:03,116 --> 17:03:04,116
training
23603
17:03:04,080 --> 17:03:05,080
and normally an acceptable use policy
23604
17:03:06,000 --> 17:03:07,000
which new people will sign and everyone
23605
17:03:08,096 --> 17:03:09,096
has to sign if there's any changes you
23606
17:03:10,560 --> 17:03:11,560
standards of acceptable behavior on the
23607
17:03:13,080 --> 17:03:14,080
network
23608
17:03:15,116 --> 17:03:16,116
for example creating strong passwords is
23609
17:03:17,880 --> 17:03:18,880
a very good one and obviously not
23610
17:03:19,796 --> 17:03:20,796
putting it on a Post-It note and
23611
17:03:21,240 --> 17:03:22,240
sticking it on your monitor
23612
17:03:23,340 --> 17:03:24,340
so we've covered Network documentation
23613
17:03:25,380 --> 17:03:26,380
why the importance parts of it diagrams
23614
17:03:29,340 --> 17:03:30,340
Asset Management the RFID
23615
17:03:32,580 --> 17:03:33,580
and monitoring your IP addresses vendors
23616
17:03:35,400 --> 17:03:36,400
and contractors all your internal
23617
17:03:37,436 --> 17:03:38,436
policies and procedures
23618
17:03:39,240 --> 17:03:40,240
all right so that's all for now thanks
23619
17:03:41,276 --> 17:03:42,276
for listening
23620
17:03:45,630 --> 17:03:46,630
[Music]
23621
17:04:01,500 --> 17:04:02,500
welcome to module 11 lesson 4 Network
23622
17:04:04,276 --> 17:04:05,276
troubleshooting model
23623
17:04:06,660 --> 17:04:07,660
he'll actually develop your own model as
23624
17:04:08,880 --> 17:04:09,880
you get some experience and obviously
23625
17:04:11,276 --> 17:04:12,276
depends on your Network whatever your
23626
17:04:14,400 --> 17:04:15,400
network or if you're managing just a
23627
17:04:16,080 --> 17:04:17,080
small part of the network and if you're
23628
17:04:18,360 --> 17:04:19,360
managing a certain OSI layout for
23629
17:04:21,240 --> 17:04:22,240
example firewalls or you're a hardware
23630
17:04:23,580 --> 17:04:24,580
engineer something like that so it could
23631
17:04:25,740 --> 17:04:26,740
vary this is the generic kind of stuff
23632
17:04:28,980 --> 17:04:29,980
that CompTIA want you to know and
23633
17:04:31,436 --> 17:04:32,436
understand and follow so we'll identify
23634
17:04:33,660 --> 17:04:34,660
the problem establish a theory of
23635
17:04:35,700 --> 17:04:36,700
probable cause
23636
17:04:37,560 --> 17:04:38,560
normally Whoever has just made a change
23637
17:04:40,320 --> 17:04:41,320
or plugged or unplugged something has
23638
17:04:42,060 --> 17:04:43,060
broken it in my experience
23639
17:04:45,000 --> 17:04:46,000
test the theory to determine the cause
23640
17:04:46,860 --> 17:04:47,860
establish a plan of action
23641
17:04:49,380 --> 17:04:50,380
and then implement the solution sort of
23642
17:04:51,416 --> 17:04:52,416
Common Sense stuff really
23643
17:04:53,700 --> 17:04:54,700
uh verification documentation
23644
17:04:57,000 --> 17:04:58,000
all right so we'll normally gather
23645
17:04:58,436 --> 17:04:59,436
information
23646
17:05:00,240 --> 17:05:01,240
duplicate the problem if possible you'll
23647
17:05:02,880 --> 17:05:03,880
normally duplicate it if it's some sort
23648
17:05:04,860 --> 17:05:05,860
of bug and you want to recreate it so
23649
17:05:07,140 --> 17:05:08,140
you can send the information to the
23650
17:05:10,020 --> 17:05:11,020
vendor to release some sort of update
23651
17:05:14,220 --> 17:05:15,220
uh question users users you've got to be
23652
17:05:16,796 --> 17:05:17,796
very careful obviously because they can
23653
17:05:18,240 --> 17:05:19,240
give you the wrong information or a lot
23654
17:05:21,596 --> 17:05:22,596
of users think they know what the
23655
17:05:23,096 --> 17:05:24,096
solution is so they'll just give you
23656
17:05:24,596 --> 17:05:25,596
answers to questions
23657
17:05:26,700 --> 17:05:27,700
that um that they think you they think
23658
17:05:29,820 --> 17:05:30,820
will direct you to what they think the
23659
17:05:31,320 --> 17:05:32,320
issue is so you'd have to be careful and
23660
17:05:33,900 --> 17:05:34,900
question more than one user if you can
23661
17:05:36,116 --> 17:05:37,116
identify symptoms determine if anything
23662
17:05:38,880 --> 17:05:39,880
has changed normally there has been a
23663
17:05:40,796 --> 17:05:41,796
change almost always not every case but
23664
17:05:43,616 --> 17:05:44,616
almost always approach multiple problems
23665
17:05:46,380 --> 17:05:47,380
individually
23666
17:05:47,936 --> 17:05:48,936
so dividing conquer kind of approach
23667
17:05:51,776 --> 17:05:52,776
okay question the obvious it's nearly
23668
17:05:54,060 --> 17:05:55,060
always something that's pretty obvious
23669
17:05:56,220 --> 17:05:57,220
I've seen people waste a lot of time and
23670
17:05:58,916 --> 17:05:59,916
energy
23671
17:05:59,776 --> 17:06:00,776
troubleshooting less likely issues when
23672
17:06:02,340 --> 17:06:03,340
it's almost always the most obvious
23673
17:06:04,796 --> 17:06:05,796
thing that's wrong
23674
17:06:06,116 --> 17:06:07,116
consider multiple approaches
23675
17:06:10,256 --> 17:06:11,256
an example is a top to bottom or bottom
23676
17:06:12,720 --> 17:06:13,720
to top using the OSI is it an
23677
17:06:14,820 --> 17:06:15,820
application problem and then moving down
23678
17:06:16,740 --> 17:06:17,740
or is it a physical problem moving up
23679
17:06:18,900 --> 17:06:19,900
and it depends on what the users are
23680
17:06:20,700 --> 17:06:21,700
telling you and what the symptoms are
23681
17:06:22,140 --> 17:06:23,140
obviously
23682
17:06:23,220 --> 17:06:24,220
I mentioned divide and conquer
23683
17:06:25,680 --> 17:06:26,680
and this all depends on your network
23684
17:06:28,256 --> 17:06:29,256
really but it could be um dividing it
23685
17:06:30,540 --> 17:06:31,540
into Hardware all Hardware or and all
23686
17:06:34,860 --> 17:06:35,860
layer 7 issues or all cabling issues
23687
17:06:38,276 --> 17:06:39,276
something like that it just depends all
23688
17:06:40,380 --> 17:06:41,380
the Divine and concrete could be
23689
17:06:41,820 --> 17:06:42,820
segments in your network so looking if a
23690
17:06:44,220 --> 17:06:45,220
particular vlans affected
23691
17:06:45,956 --> 17:06:46,956
or all vlans test the theory once it's
23692
17:06:49,456 --> 17:06:50,456
confirmed and determine the next steps
23693
17:06:52,140 --> 17:06:53,140
to resolve the problem for example if
23694
17:06:54,180 --> 17:06:55,180
it's an email issue then try sending an
23695
17:06:56,756 --> 17:06:57,756
email try it from a different users
23696
17:06:59,936 --> 17:07:00,936
um device to see if there's more than
23697
17:07:01,560 --> 17:07:02,560
one person affected if the theory is not
23698
17:07:04,140 --> 17:07:05,140
confirmed you start at the beginning
23699
17:07:06,660 --> 17:07:07,660
plan of action obviously and if you can
23700
17:07:09,956 --> 17:07:10,956
fix it there and then fix it if it's
23701
17:07:11,756 --> 17:07:12,756
requiring a network downtime then you're
23702
17:07:14,456 --> 17:07:15,456
going to need to schedule an outage if
23703
17:07:16,140 --> 17:07:17,140
you're working on a production Network
23704
17:07:17,720 --> 17:07:18,720
again and generally this sort of issue
23705
17:07:20,820 --> 17:07:21,820
is decided by this seniority manager or
23706
17:07:23,640 --> 17:07:24,640
network manager
23707
17:07:25,740 --> 17:07:26,740
potential effects what's going to happen
23708
17:07:27,240 --> 17:07:28,240
is it going to cause make the problem
23709
17:07:28,796 --> 17:07:29,796
worse is it going to fix it is it going
23710
17:07:30,540 --> 17:07:31,540
to cause a different problem somewhere
23711
17:07:32,040 --> 17:07:33,040
else
23712
17:07:33,180 --> 17:07:34,180
when you implement the solution escalate
23713
17:07:35,400 --> 17:07:36,400
is necessary again you normally need
23714
17:07:38,060 --> 17:07:39,060
verification of somebody else a senior
23715
17:07:40,980 --> 17:07:41,980
manager that this is um
23716
17:07:43,256 --> 17:07:44,256
the correct course of action
23717
17:07:45,956 --> 17:07:46,956
verifiable system functionality
23718
17:07:49,140 --> 17:07:50,140
speak to the user who actually logged
23719
17:07:51,296 --> 17:07:52,296
the issue and see if it's resolved for
23720
17:07:53,340 --> 17:07:54,340
them and whoever else was experiencing
23721
17:07:55,020 --> 17:07:56,020
it if applicable Implement preventative
23722
17:07:57,840 --> 17:07:58,840
measures document the outcomes findings
23723
17:08:01,616 --> 17:08:02,616
and actions
23724
17:08:04,080 --> 17:08:05,080
this is basically useful if somebody
23725
17:08:05,820 --> 17:08:06,820
else deals with the same problem I know
23726
17:08:08,756 --> 17:08:09,756
when I worked at Cisco attack you could
23727
17:08:10,436 --> 17:08:11,436
often put in
23728
17:08:11,640 --> 17:08:12,640
error messages and similar things or
23729
17:08:14,880 --> 17:08:15,880
look at certain model numbers and you'd
23730
17:08:16,796 --> 17:08:17,796
often find somebody else that had the
23731
17:08:18,296 --> 17:08:19,296
same problem and you could see how they
23732
17:08:20,756 --> 17:08:21,756
fixed it or if they'd established that a
23733
17:08:22,436 --> 17:08:23,436
bug had been found and then if that
23734
17:08:24,540 --> 17:08:25,540
bug's been fixed in another iOS
23735
17:08:27,776 --> 17:08:28,776
all right so pretty Common Sense stuff
23736
17:08:29,756 --> 17:08:30,756
hopefully but we've put it into writing
23737
17:08:32,276 --> 17:08:33,276
now so you've got uh some sort of method
23738
17:08:34,080 --> 17:08:35,080
to follow I'd identify the problem
23739
17:08:36,720 --> 17:08:37,720
establish your theory test it plan of
23740
17:08:39,596 --> 17:08:40,596
action implement the solution verify
23741
17:08:42,840 --> 17:08:43,840
document you need to write that down a
23742
17:08:46,080 --> 17:08:47,080
few times you get the correct order in
23743
17:08:47,580 --> 17:08:48,580
case it's a drag and drop type question
23744
17:08:49,740 --> 17:08:50,740
all right so that's the end thanks for
23745
17:08:52,200 --> 17:08:53,200
listening
23746
17:08:59,030 --> 17:09:00,030
[Music]
23747
17:09:07,756 --> 17:09:08,756
thank you
23748
17:09:18,240 --> 17:09:19,240
foreign
23749
17:09:19,616 --> 17:09:20,616
network security security fundamentals
23750
17:09:24,180 --> 17:09:25,180
in the last lesson we discussed managing
23751
17:09:26,820 --> 17:09:27,820
a network and administering a network
23752
17:09:28,500 --> 17:09:29,500
this ranged everywhere from
23753
17:09:30,180 --> 17:09:31,180
troubleshooting to speed optimization
23754
17:09:32,400 --> 17:09:33,400
and in this lesson in the next four
23755
17:09:35,096 --> 17:09:36,096
modules we're going to discuss security
23756
17:09:36,900 --> 17:09:37,900
now just like with a plus we talked
23757
17:09:39,776 --> 17:09:40,776
about networking and Security in network
23758
17:09:43,256 --> 17:09:44,256
plus we're going to talk about security
23759
17:09:45,436 --> 17:09:46,436
with the understanding that there is a
23760
17:09:48,540 --> 17:09:49,540
whole other certification and a whole
23761
17:09:50,040 --> 17:09:51,040
other lesson that revolves specifically
23762
17:09:52,256 --> 17:09:53,256
around this uh concept so we're just
23763
17:09:56,096 --> 17:09:57,096
going to sort of brush over the
23764
17:09:57,480 --> 17:09:58,480
important things that we need to know in
23765
17:10:00,000 --> 17:10:01,000
a network Plus or network Administration
23766
17:10:02,040 --> 17:10:03,040
environment so to start us off we're
23767
17:10:04,980 --> 17:10:05,980
going to talk about the basis of network
23768
17:10:07,200 --> 17:10:08,200
security and the fundamentals that we're
23769
17:10:09,180 --> 17:10:10,180
going to discuss in the next three
23770
17:10:10,380 --> 17:10:11,380
modules
23771
17:10:11,520 --> 17:10:12,520
so this involves discussing network
23772
17:10:13,680 --> 17:10:14,680
security and identifying exactly what it
23773
17:10:15,900 --> 17:10:16,900
is when we talk about the basics then
23774
17:10:18,240 --> 17:10:19,240
we're going to go over some of the
23775
17:10:19,256 --> 17:10:20,256
things that are fundamental to having a
23776
17:10:21,416 --> 17:10:22,416
secure network these include keeping the
23777
17:10:23,756 --> 17:10:24,756
network up to date
23778
17:10:25,680 --> 17:10:26,680
strong passwords
23779
17:10:27,900 --> 17:10:28,900
having a secure VPN virtual private
23780
17:10:30,540 --> 17:10:31,540
Network
23781
17:10:31,936 --> 17:10:32,936
administrating user access in a proper
23782
17:10:35,160 --> 17:10:36,160
way
23783
17:10:36,240 --> 17:10:37,240
and making sure to remove any inactive
23784
17:10:39,116 --> 17:10:40,116
accounts now the reason I focus on these
23785
17:10:41,340 --> 17:10:42,340
fundamentals are these are the things
23786
17:10:42,596 --> 17:10:43,596
that we'll see on the network plus exam
23787
17:10:45,416 --> 17:10:46,416
now the word security means the same
23788
17:10:47,880 --> 17:10:48,880
thing just about anywhere you look when
23789
17:10:49,860 --> 17:10:50,860
it comes to homes it may refer to Locks
23790
17:10:52,200 --> 17:10:53,200
and alarm systems but when it comes to
23791
17:10:54,000 --> 17:10:55,000
networks it refers to a lot of different
23792
17:10:55,796 --> 17:10:56,796
methods but the concept is still the
23793
17:10:58,080 --> 17:10:59,080
same the point of security regardless of
23794
17:11:00,360 --> 17:11:01,360
where it is or what it's protecting is
23795
17:11:02,520 --> 17:11:03,520
to keep the threats out and the
23796
17:11:04,256 --> 17:11:05,256
valuables in think of a bank vault the
23797
17:11:06,596 --> 17:11:07,596
door to a bank fault is a few feet thick
23798
17:11:09,596 --> 17:11:10,596
it's made of very sturdy metal and this
23799
17:11:11,936 --> 17:11:12,936
is because the bank needs to keep the
23800
17:11:14,456 --> 17:11:15,456
money invaluable securely inside while
23801
17:11:17,040 --> 17:11:18,040
also keeping the potential threats
23802
17:11:18,596 --> 17:11:19,596
outside now if someone really wants to
23803
17:11:21,416 --> 17:11:22,416
break into a bank and steal the money
23804
17:11:22,860 --> 17:11:23,860
they're going to be able to what we want
23805
17:11:24,840 --> 17:11:25,840
to do is make it as hard as possible for
23806
17:11:26,936 --> 17:11:27,936
them to come in and steal the money
23807
17:11:28,256 --> 17:11:29,256
nothing is beyond anyone's purview it's
23808
17:11:32,160 --> 17:11:33,160
simply that we want to make it as
23809
17:11:33,720 --> 17:11:34,720
difficult as possible for these thieves
23810
17:11:35,456 --> 17:11:36,456
hackers or whoever to get in and take it
23811
17:11:37,560 --> 17:11:38,560
now the same principle applies to
23812
17:11:39,360 --> 17:11:40,360
network security on a network data can
23813
17:11:41,880 --> 17:11:42,880
sometimes be more valuable than money in
23814
17:11:44,520 --> 17:11:45,520
fact I know a lot of CEO cios CFOs out
23815
17:11:48,180 --> 17:11:49,180
there who would much prefer that you
23816
17:11:49,680 --> 17:11:50,680
steal some of their money rather than
23817
17:11:51,360 --> 17:11:52,360
steal their data especially when it
23818
17:11:52,740 --> 17:11:53,740
comes to user data or to private or
23819
17:11:56,220 --> 17:11:57,220
privileged information because this
23820
17:11:58,436 --> 17:11:59,436
stuff is literally Priceless this is why
23821
17:12:00,720 --> 17:12:01,720
it's really important to have a properly
23822
17:12:02,520 --> 17:12:03,520
secured Network and make sure that it
23823
17:12:04,680 --> 17:12:05,680
stays that way and these are two
23824
17:12:06,296 --> 17:12:07,296
different things securing it and then
23825
17:12:07,980 --> 17:12:08,980
monitoring it to make sure it remains
23826
17:12:10,200 --> 17:12:11,200
secured
23827
17:12:11,520 --> 17:12:12,520
now it's very important to make sure
23828
17:12:12,900 --> 17:12:13,900
that everything on the network is kept
23829
17:12:15,000 --> 17:12:16,000
up to date when programs and patches
23830
17:12:17,400 --> 17:12:18,400
have been used for a long time and
23831
17:12:19,140 --> 17:12:20,140
they're well known the attackers who've
23832
17:12:21,296 --> 17:12:22,296
had an opportunity to find holes with
23833
17:12:22,980 --> 17:12:23,980
them begin to make use of those holes
23834
17:12:26,456 --> 17:12:27,456
and hack through them
23835
17:12:27,956 --> 17:12:28,956
so the longer something is out there and
23836
17:12:29,756 --> 17:12:30,756
being used without a new version the
23837
17:12:32,220 --> 17:12:33,220
more times attackers have to find
23838
17:12:34,436 --> 17:12:35,436
exploits within the program or the patch
23839
17:12:37,020 --> 17:12:38,020
this is why as Network admins we need to
23840
17:12:39,480 --> 17:12:40,480
make sure that all the programs and
23841
17:12:41,400 --> 17:12:42,400
patches are kept up to date programs
23842
17:12:43,796 --> 17:12:44,796
that get used often should be updated as
23843
17:12:46,680 --> 17:12:47,680
soon as there is a new version or as
23844
17:12:48,956 --> 17:12:49,956
soon as a new version proves to not be
23845
17:12:50,756 --> 17:12:51,756
buggy now when running a device on
23846
17:12:52,860 --> 17:12:53,860
Windows the admin should always check to
23847
17:12:55,020 --> 17:12:56,020
see if there's anything available in
23848
17:12:56,640 --> 17:12:57,640
Windows Live update or Microsoft update
23849
17:12:58,796 --> 17:12:59,796
which we have talked about in a plus
23850
17:13:01,380 --> 17:13:02,380
quite a bit now usually this can install
23851
17:13:03,840 --> 17:13:04,840
new drivers in patches that have been
23852
17:13:05,520 --> 17:13:06,520
updated for performance and security but
23853
17:13:07,796 --> 17:13:08,796
other things we need to be aware of are
23854
17:13:09,360 --> 17:13:10,360
Adobe products Java which is integrated
23855
17:13:11,756 --> 17:13:12,756
into a lot of browsers and the browsers
23856
17:13:14,520 --> 17:13:15,520
themselves to make sure that they're all
23857
17:13:16,200 --> 17:13:17,200
tight and secure once again we don't
23858
17:13:18,480 --> 17:13:19,480
want to update things immediately
23859
17:13:19,740 --> 17:13:20,740
because maybe they'll bring down the
23860
17:13:21,660 --> 17:13:22,660
system but we need to weigh this against
23861
17:13:23,700 --> 17:13:24,700
the fact that if a patch goes out there
23862
17:13:25,740 --> 17:13:26,740
to to plug up a security flaw that as
23863
17:13:30,000 --> 17:13:31,000
soon as it goes out there the hackers
23864
17:13:31,860 --> 17:13:32,860
now know oh look there was a security
23865
17:13:34,140 --> 17:13:35,140
flaw and now they can begin to make use
23866
17:13:36,956 --> 17:13:37,956
of that security flaw until you update
23867
17:13:39,720 --> 17:13:40,720
things so what we're really looking to
23868
17:13:41,276 --> 17:13:42,276
do is balance
23869
17:13:45,480 --> 17:13:46,480
updating immediately
23870
17:13:49,916 --> 17:13:50,916
versus
23871
17:13:52,916 --> 17:13:53,916
buggy Updates this is an important thing
23872
17:13:55,680 --> 17:13:56,680
to keep in mind
23873
17:13:58,436 --> 17:13:59,436
now it's very important that we keep
23874
17:14:01,916 --> 17:14:02,916
another aspect of security in mind when
23875
17:14:04,796 --> 17:14:05,796
it comes not just to our networks but to
23876
17:14:06,360 --> 17:14:07,360
just about anything we're dealing with
23877
17:14:08,276 --> 17:14:09,276
on devices and this is our passport our
23878
17:14:10,256 --> 17:14:11,256
passwords people tend to think that just
23879
17:14:12,296 --> 17:14:13,296
because something is password protected
23880
17:14:13,796 --> 17:14:14,796
that means it's safe but this really
23881
17:14:16,080 --> 17:14:17,080
isn't true something that's protected by
23882
17:14:18,180 --> 17:14:19,180
a password is ultimately safer than
23883
17:14:20,520 --> 17:14:21,520
something that's not but a password is
23884
17:14:22,796 --> 17:14:23,796
nearly useless unless it's a strong one
23885
17:14:24,540 --> 17:14:25,540
think about all the movies in which
23886
17:14:26,756 --> 17:14:27,756
someone has to figure out someone's
23887
17:14:28,020 --> 17:14:29,020
password looks around the room sees a
23888
17:14:30,180 --> 17:14:31,180
picture types in the name of that person
23889
17:14:31,740 --> 17:14:32,740
and Bam they're in attackers can use
23890
17:14:34,256 --> 17:14:35,256
things called key loggers in order to
23891
17:14:37,916 --> 17:14:38,916
log uh what passwords you are entering
23892
17:14:41,160 --> 17:14:42,160
on your computer and then send that over
23893
17:14:43,080 --> 17:14:44,080
to the hacker they can then take the
23894
17:14:45,416 --> 17:14:46,416
letters symbols Etc and being used and
23895
17:14:47,580 --> 17:14:48,580
try to piece together what the password
23896
17:14:48,956 --> 17:14:49,956
could be depending on the attacker they
23897
17:14:51,180 --> 17:14:52,180
might be really successful at stealing
23898
17:14:53,160 --> 17:14:54,160
your password simply by just observing
23899
17:14:55,500 --> 17:14:56,500
what you type in this is called shoulder
23900
17:14:58,256 --> 17:14:59,256
surfing
23901
17:15:00,480 --> 17:15:01,480
and it is a big problem when we think
23902
17:15:02,640 --> 17:15:03,640
about ATMs people typing at their office
23903
17:15:05,220 --> 17:15:06,220
and so on this is a huge problem in
23904
17:15:07,860 --> 17:15:08,860
general but it's really problematic if
23905
17:15:09,956 --> 17:15:10,956
you use the same password for more than
23906
17:15:11,700 --> 17:15:12,700
one thing think about it as soon as they
23907
17:15:14,220 --> 17:15:15,220
get one password they have access to
23908
17:15:15,956 --> 17:15:16,956
everything especially if they get access
23909
17:15:17,880 --> 17:15:18,880
to your email they now have access to
23910
17:15:20,520 --> 17:15:21,520
your entire life because they can reset
23911
17:15:22,320 --> 17:15:23,320
everything through your email so it's
23912
17:15:24,540 --> 17:15:25,540
really important to keep different
23913
17:15:25,980 --> 17:15:26,980
passwords for each sort of service that
23914
17:15:29,220 --> 17:15:30,220
you access in a general rule you
23915
17:15:31,616 --> 17:15:32,616
shouldn't use the same password for more
23916
17:15:33,240 --> 17:15:34,240
than one thing this can end up becoming
23917
17:15:35,160 --> 17:15:36,160
really confusing if you're dealing with
23918
17:15:36,776 --> 17:15:37,776
a lot of different accounts that require
23919
17:15:38,040 --> 17:15:39,040
many different passwords so there are
23920
17:15:40,080 --> 17:15:41,080
some programs that act as basically
23921
17:15:42,296 --> 17:15:43,296
password vaults and they require one
23922
17:15:44,880 --> 17:15:45,880
master password to access them and then
23923
17:15:47,220 --> 17:15:48,220
you have all of your information stored
23924
17:15:48,956 --> 17:15:49,956
inside of those but I think some of
23925
17:15:52,020 --> 17:15:53,020
those just have as many problems as
23926
17:15:53,756 --> 17:15:54,756
regular passwords all you need to do is
23927
17:15:55,740 --> 17:15:56,740
get access to the one program and
23928
17:15:58,500 --> 17:15:59,500
suddenly you have access to all of the
23929
17:16:00,900 --> 17:16:01,900
password programs so it's important
23930
17:16:03,480 --> 17:16:04,480
sometimes for you to create a long
23931
17:16:05,640 --> 17:16:06,640
random password word that can contain
23932
17:16:07,796 --> 17:16:08,796
special characters like slashes
23933
17:16:09,540 --> 17:16:10,540
ampersands Etc these programs can do
23934
17:16:11,820 --> 17:16:12,820
that as well but the problem with that
23935
17:16:13,436 --> 17:16:14,436
is we're also not going to be able to
23936
17:16:15,116 --> 17:16:16,116
memorize that
23937
17:16:16,380 --> 17:16:17,380
so and another important aspect of
23938
17:16:19,256 --> 17:16:20,256
password Corrections uh protection
23939
17:16:21,540 --> 17:16:22,540
rather when it comes to strong passwords
23940
17:16:23,640 --> 17:16:24,640
is to use random letters symbols Etc and
23941
17:16:27,776 --> 17:16:28,776
long passwords which are always better
23942
17:16:29,160 --> 17:16:30,160
than short ones
23943
17:16:31,020 --> 17:16:32,020
for instance using the password
23944
17:16:34,096 --> 17:16:35,096
password123 is really weak whereas this
23945
17:16:37,380 --> 17:16:38,380
one on the right which I can't even
23946
17:16:39,180 --> 17:16:40,180
pronounce is really strong now of course
23947
17:16:41,276 --> 17:16:42,276
the problem with this is it's difficult
23948
17:16:43,560 --> 17:16:44,560
to memorize and if it's difficult to
23949
17:16:45,720 --> 17:16:46,720
memorize you're probably going to have
23950
17:16:47,096 --> 17:16:48,096
to write it down if you write it down
23951
17:16:49,320 --> 17:16:50,320
that gives someone something to steal or
23952
17:16:51,360 --> 17:16:52,360
you put it in a password Vault or this
23953
17:16:53,400 --> 17:16:54,400
is maybe made up automatically but in
23954
17:16:56,220 --> 17:16:57,220
all these cases one password can get
23955
17:16:58,200 --> 17:16:59,200
access to all the passwords and so it's
23956
17:17:00,720 --> 17:17:01,720
important again we talked in the
23957
17:17:02,756 --> 17:17:03,756
previous one about we sort of have to
23958
17:17:05,400 --> 17:17:06,400
decide whether we want to update
23959
17:17:07,080 --> 17:17:08,080
something immediately or whether we want
23960
17:17:09,060 --> 17:17:10,060
to update it you know after a little bit
23961
17:17:11,640 --> 17:17:12,640
after it's been tested the same sort of
23962
17:17:13,140 --> 17:17:14,140
thing with passwords we don't want
23963
17:17:14,640 --> 17:17:15,640
something too weak but we also don't
23964
17:17:16,680 --> 17:17:17,680
want something too strong that we can't
23965
17:17:18,480 --> 17:17:19,480
remember so the best thing I think is to
23966
17:17:21,296 --> 17:17:22,296
think about for instance a pass a code
23967
17:17:25,980 --> 17:17:26,980
that for yourself so for instance a
23968
17:17:28,740 --> 17:17:29,740
common one with the term password is to
23969
17:17:31,980 --> 17:17:32,980
replace
23970
17:17:34,200 --> 17:17:35,200
the A's with ATS and the O's with zeros
23971
17:17:37,860 --> 17:17:38,860
if you think about creating your own
23972
17:17:40,200 --> 17:17:41,200
password we could do this for instance
23973
17:17:42,416 --> 17:17:43,416
let's say we wanted to turn this secure
23974
17:17:44,520 --> 17:17:45,520
and organized into a password well I
23975
17:17:47,640 --> 17:17:48,640
could replace the S with fives
23976
17:17:50,220 --> 17:17:51,220
I could replace the ease with threes
23977
17:17:54,840 --> 17:17:55,840
I can replace the A's with and
23978
17:17:57,360 --> 17:17:58,360
ampersands
23979
17:18:00,660 --> 17:18:01,660
and so on and so forth
23980
17:18:04,860 --> 17:18:05,860
even an I replace that with a
23981
17:18:07,380 --> 17:18:08,380
exclamation point or the number one
23982
17:18:12,720 --> 17:18:13,720
and voila I've just created what looks
23983
17:18:15,240 --> 17:18:16,240
to the plane eye
23984
17:18:16,860 --> 17:18:17,860
as a pretty s complex password that a
23985
17:18:21,180 --> 17:18:22,180
computer wouldn't be able to necessarily
23986
17:18:22,500 --> 17:18:23,500
break but you remember it because you've
23987
17:18:25,380 --> 17:18:26,380
come up with your own code of how you're
23988
17:18:26,936 --> 17:18:27,936
going to replace certain symbols and
23989
17:18:29,456 --> 17:18:30,456
numbers and it wouldn't hurt to throw in
23990
17:18:31,860 --> 17:18:32,860
a couple uppercase letters there as well
23991
17:18:35,096 --> 17:18:36,096
now with virtual private networks
23992
17:18:37,020 --> 17:18:38,020
there's a lot that can go wrong security
23993
17:18:38,640 --> 17:18:39,640
wise because it travels over a public
23994
17:18:41,340 --> 17:18:42,340
network in order to collect connect to
23995
17:18:43,256 --> 17:18:44,256
your local land and the users remotely
23996
17:18:45,480 --> 17:18:46,480
connect an attack can happen from
23997
17:18:47,400 --> 17:18:48,400
literally anywhere so in order to help
23998
17:18:49,680 --> 17:18:50,680
stop attacks the admin needs to require
23999
17:18:51,900 --> 17:18:52,900
remote users to have multiple points of
24000
17:18:54,596 --> 17:18:55,596
identification remember in a plus we
24001
17:18:58,020 --> 17:18:59,020
talked about having multi-authentication
24002
17:19:04,380 --> 17:19:05,380
and remember authentication we have
24003
17:19:06,180 --> 17:19:07,180
three different things
24004
17:19:07,616 --> 17:19:08,616
something you know
24005
17:19:10,256 --> 17:19:11,256
something you have
24006
17:19:12,416 --> 17:19:13,416
it's something you are
24007
17:19:15,416 --> 17:19:16,416
so if we're going to use multiple forms
24008
17:19:17,820 --> 17:19:18,820
of identification
24009
17:19:19,640 --> 17:19:20,640
maybe one thing we want to do is have a
24010
17:19:22,140 --> 17:19:23,140
standard username and password and also
24011
17:19:24,060 --> 17:19:25,060
a pin or security question they would
24012
17:19:26,040 --> 17:19:27,040
have to answer these both fall under
24013
17:19:27,956 --> 17:19:28,956
something you know we could also give
24014
17:19:29,756 --> 17:19:30,756
them a fob key that has a rotating
24015
17:19:31,796 --> 17:19:32,796
password on it this would be something
24016
17:19:33,296 --> 17:19:34,296
they have it makes it more difficult if
24017
17:19:35,880 --> 17:19:36,880
I use multiple forms of this
24018
17:19:38,096 --> 17:19:39,096
authentication and that way it's not
24019
17:19:41,276 --> 17:19:42,276
just things that are written down or
24020
17:19:42,840 --> 17:19:43,840
known it's also things that are have had
24021
17:19:45,060 --> 17:19:46,060
or even better things that you are for
24022
17:19:47,640 --> 17:19:48,640
instance a retinal scan fingerprint
24023
17:19:49,616 --> 17:19:50,616
voice recognition
24024
17:19:51,360 --> 17:19:52,360
Etc the point is the more of these you
24025
17:19:53,936 --> 17:19:54,936
have the easier it is for you to keep
24026
17:19:57,776 --> 17:19:58,776
your stuff secure however it's also more
24027
17:20:01,020 --> 17:20:02,020
difficult to log in and it's going to
24028
17:20:03,116 --> 17:20:04,116
take more time so again we're dealing
24029
17:20:05,096 --> 17:20:06,096
with time
24030
17:20:06,416 --> 17:20:07,416
and ease
24031
17:20:08,520 --> 17:20:09,520
versus security and we have to find the
24032
17:20:11,096 --> 17:20:12,096
right balance
24033
17:20:12,180 --> 17:20:13,180
because we don't want people to get so
24034
17:20:13,740 --> 17:20:14,740
turned off by all the heightened
24035
17:20:15,956 --> 17:20:16,956
security that then they can't use our
24036
17:20:17,880 --> 17:20:18,880
product
24037
17:20:18,776 --> 17:20:19,776
it also might be necessary to have a
24038
17:20:20,820 --> 17:20:21,820
firewall between the VPN and the
24039
17:20:22,616 --> 17:20:23,616
physical Network the firewall acts as a
24040
17:20:24,956 --> 17:20:25,956
sort of last line of defense and if
24041
17:20:26,700 --> 17:20:27,700
somehow an attacker manages to get
24042
17:20:28,796 --> 17:20:29,796
through the points of identification the
24043
17:20:31,320 --> 17:20:32,320
firewall might be able to stop them from
24044
17:20:32,936 --> 17:20:33,936
connecting to the network based on where
24045
17:20:34,680 --> 17:20:35,680
they are the information they're trying
24046
17:20:35,936 --> 17:20:36,936
to transmit if they're using an unknown
24047
17:20:38,220 --> 17:20:39,220
or untrusted
24048
17:20:39,840 --> 17:20:40,840
IP address the firewall may be able to
24049
17:20:42,416 --> 17:20:43,416
stop them before they connect the local
24050
17:20:44,340 --> 17:20:45,340
area network
24051
17:20:46,500 --> 17:20:47,500
now it's often the case that users have
24052
17:20:48,540 --> 17:20:49,540
to access things that they have no
24053
17:20:50,520 --> 17:20:51,520
business accessing for example someone
24054
17:20:52,740 --> 17:20:53,740
in the graphic design part of the
24055
17:20:54,116 --> 17:20:55,116
company has no need to access the
24056
17:20:55,796 --> 17:20:56,796
accounting records of the company and
24057
17:20:57,660 --> 17:20:58,660
sometimes however users are given
24058
17:20:59,756 --> 17:21:00,756
permissions to access data like this
24059
17:21:01,560 --> 17:21:02,560
simply because it's overlooked by the
24060
17:21:03,296 --> 17:21:04,296
administrator so this is a huge security
24061
17:21:05,456 --> 17:21:06,456
issue and one that's easy to fix and
24062
17:21:07,616 --> 17:21:08,616
needs to be looked after with care the
24063
17:21:09,900 --> 17:21:10,900
admin should only make sure that users
24064
17:21:11,936 --> 17:21:12,936
are given only access to the data they
24065
17:21:14,936 --> 17:21:15,936
need to do their job this is what we
24066
17:21:17,400 --> 17:21:18,400
call the principle of least
24067
17:21:22,256 --> 17:21:23,256
privilege now this change can be made by
24068
17:21:25,560 --> 17:21:26,560
password protecting
24069
17:21:28,740 --> 17:21:29,740
or it can be made
24070
17:21:31,080 --> 17:21:32,080
using group policy
24071
17:21:33,416 --> 17:21:34,416
meaning that we have an Accounting Group
24072
17:21:36,596 --> 17:21:37,596
and we have a Marketing Group if you're
24073
17:21:39,480 --> 17:21:40,480
placed into one of those groups then
24074
17:21:41,456 --> 17:21:42,456
you're not going to be able to uh access
24075
17:21:44,456 --> 17:21:45,456
anything except for what your group has
24076
17:21:46,436 --> 17:21:47,436
access to
24077
17:21:48,660 --> 17:21:49,660
now the other thing we want to do is
24078
17:21:50,096 --> 17:21:51,096
make sure to clean up inactive accounts
24079
17:21:52,436 --> 17:21:53,436
when a worker leaves the company the
24080
17:21:54,900 --> 17:21:55,900
first thing the admin needs to do is to
24081
17:21:57,000 --> 17:21:58,000
change the password to the user's
24082
17:21:58,380 --> 17:21:59,380
account or what we call deactivate the
24083
17:22:01,500 --> 17:22:02,500
account it'll be a very bad thing if a
24084
17:22:03,540 --> 17:22:04,540
for former employee were to access the
24085
17:22:05,640 --> 17:22:06,640
company's files and who knows what they
24086
17:22:07,560 --> 17:22:08,560
could do with those especially if they
24087
17:22:09,000 --> 17:22:10,000
were fired so once the passwords has
24088
17:22:11,096 --> 17:22:12,096
been changed there's no way for them to
24089
17:22:12,596 --> 17:22:13,596
access the account but it's not
24090
17:22:14,340 --> 17:22:15,340
necessary for the admin to delete the
24091
17:22:16,560 --> 17:22:17,560
account right away if the employee was
24092
17:22:18,840 --> 17:22:19,840
to come back to the company soon after
24093
17:22:20,456 --> 17:22:21,456
and needed to access their old files
24094
17:22:21,956 --> 17:22:22,956
they could be given a temporary password
24095
17:22:23,700 --> 17:22:24,700
and then monitored to make sure they
24096
17:22:25,560 --> 17:22:26,560
could get their old information however
24097
17:22:28,140 --> 17:22:29,140
if an account has been inactive for a
24098
17:22:30,660 --> 17:22:31,660
while it should be deleted or
24099
17:22:33,480 --> 17:22:34,480
discontinued an idle account is really
24100
17:22:36,060 --> 17:22:37,060
dangerous thing to have on your network
24101
17:22:37,436 --> 17:22:38,436
if an attacker is about to access this
24102
17:22:39,720 --> 17:22:40,720
account they could easily slip past
24103
17:22:41,276 --> 17:22:42,276
unnoticed on the network until something
24104
17:22:43,560 --> 17:22:44,560
actually happens we wouldn't really know
24105
17:22:45,180 --> 17:22:46,180
that there's a problem so in order to
24106
17:22:46,860 --> 17:22:47,860
prevent this we really want to delete
24107
17:22:48,060 --> 17:22:49,060
accounts soon as the users do not need
24108
17:22:50,700 --> 17:22:51,700
them anymore this is why generally HR
24109
17:22:52,980 --> 17:22:53,980
and IT talk to one another so we can
24110
17:22:54,956 --> 17:22:55,956
make sure once we let a person go or
24111
17:22:57,840 --> 17:22:58,840
fire someone their account is turned off
24112
17:23:00,540 --> 17:23:01,540
almost immediately
24113
17:23:02,520 --> 17:23:03,520
all right so these are some of the
24114
17:23:04,140 --> 17:23:05,140
fundamentals we talked about the
24115
17:23:05,880 --> 17:23:06,880
necessity of network security remember
24116
17:23:08,180 --> 17:23:09,180
data can sometimes be more important
24117
17:23:11,400 --> 17:23:12,400
than money because it's going to cost a
24118
17:23:13,860 --> 17:23:14,860
lot of money in order to recover or make
24119
17:23:16,080 --> 17:23:17,080
up for the loss of data we also
24120
17:23:18,360 --> 17:23:19,360
identified some of the fundamentals of a
24121
17:23:19,796 --> 17:23:20,796
secure network first of all we talked
24122
17:23:21,840 --> 17:23:22,840
about keeping things up to date we
24123
17:23:23,700 --> 17:23:24,700
talked about keeping up the firmware
24124
17:23:25,560 --> 17:23:26,560
drivers
24125
17:23:29,160 --> 17:23:30,160
operating systems
24126
17:23:31,616 --> 17:23:32,616
patches to Software
24127
17:23:34,980 --> 17:23:35,980
Etc and we're always dealing with a
24128
17:23:37,080 --> 17:23:38,080
balancing act here are we
24129
17:23:39,776 --> 17:23:40,776
doing things immediately
24130
17:23:45,480 --> 17:23:46,480
or are we going to wait and possibly uh
24131
17:23:49,616 --> 17:23:50,616
be susceptible but we might have buggy
24132
17:23:52,380 --> 17:23:53,380
updates
24133
17:23:54,240 --> 17:23:55,240
so we sort of want to find a good medium
24134
17:23:57,240 --> 17:23:58,240
middle of the road solution there
24135
17:23:58,860 --> 17:23:59,860
realizing the longer we wait the more
24136
17:24:01,380 --> 17:24:02,380
susceptible we are to attacks we also
24137
17:24:03,840 --> 17:24:04,840
want to make sure to have strong
24138
17:24:05,276 --> 17:24:06,276
passwords
24139
17:24:06,900 --> 17:24:07,900
remember a strong password generally
24140
17:24:09,540 --> 17:24:10,540
means it's 15 characters or more the
24141
17:24:13,680 --> 17:24:14,680
longer the better
24142
17:24:15,240 --> 17:24:16,240
we have numbers
24143
17:24:18,296 --> 17:24:19,296
symbols
24144
17:24:21,240 --> 17:24:22,240
lowercase letters
24145
17:24:23,520 --> 17:24:24,520
uppercase letters
24146
17:24:26,400 --> 17:24:27,400
and we want to use them in a varied
24147
17:24:29,400 --> 17:24:30,400
random combination
24148
17:24:31,560 --> 17:24:32,560
we also want to make sure that we're not
24149
17:24:34,200 --> 17:24:35,200
reusing the same passwords
24150
17:24:37,980 --> 17:24:38,980
and don't write them down that's always
24151
17:24:40,740 --> 17:24:41,740
a problem
24152
17:24:42,776 --> 17:24:43,776
now of course again we have a balancing
24153
17:24:44,820 --> 17:24:45,820
act here because the more difficult it
24154
17:24:47,040 --> 17:24:48,040
is
24155
17:24:48,116 --> 17:24:49,116
the
24156
17:24:50,360 --> 17:24:51,360
more difficult to password rather than
24157
17:24:52,860 --> 17:24:53,860
the more likely someone's going to write
24158
17:24:54,240 --> 17:24:55,240
it down and so we need to also make sure
24159
17:24:56,820 --> 17:24:57,820
that the passwords are have a certain
24160
17:24:58,980 --> 17:24:59,980
degree of ease of use
24161
17:25:00,776 --> 17:25:01,776
we also are probably going to want the
24162
17:25:02,276 --> 17:25:03,276
passwords to expire every once in a
24163
17:25:04,140 --> 17:25:05,140
while
24164
17:25:04,740 --> 17:25:05,740
and so on and so forth with a VPN we
24165
17:25:08,040 --> 17:25:09,040
need to make sure that there are
24166
17:25:09,240 --> 17:25:10,240
multiple forms of Authentication
24167
17:25:14,340 --> 17:25:15,340
remember the three things we have when
24168
17:25:16,256 --> 17:25:17,256
it comes to authentication something you
24169
17:25:18,540 --> 17:25:19,540
have
24170
17:25:19,860 --> 17:25:20,860
like a fob something you know like a
24171
17:25:22,140 --> 17:25:23,140
password and something you are like a
24172
17:25:24,000 --> 17:25:25,000
retinal scan or a biometrics
24173
17:25:27,296 --> 17:25:28,296
when it comes to user access we want to
24174
17:25:29,640 --> 17:25:30,640
practice the principle of least
24175
17:25:31,700 --> 17:25:32,700
privilege meaning you're only going to
24176
17:25:34,256 --> 17:25:35,256
be given access to that which you need
24177
17:25:36,776 --> 17:25:37,776
access to to do your job accounting does
24178
17:25:38,936 --> 17:25:39,936
not need access to marketing and vice
24179
17:25:40,860 --> 17:25:41,860
versa finally we want to make sure to
24180
17:25:43,860 --> 17:25:44,860
disable
24181
17:25:44,820 --> 17:25:45,820
or delete inactive accounts keeping in
24182
17:25:48,596 --> 17:25:49,596
mind of course that someone who leaves
24183
17:25:50,700 --> 17:25:51,700
the company might need to come back and
24184
17:25:52,436 --> 17:25:53,436
therefore we might want to make it easy
24185
17:25:53,756 --> 17:25:54,756
for them to have access to their old
24186
17:25:55,256 --> 17:25:56,256
stuff
24187
17:26:01,030 --> 17:26:02,030
[Music]
24188
17:26:21,000 --> 17:26:22,000
network security authentication
24189
17:26:23,900 --> 17:26:24,900
authorization and accounting
24190
17:26:27,360 --> 17:26:28,360
in the last module we started off this
24191
17:26:29,400 --> 17:26:30,400
lesson by discussing the fundamentals of
24192
17:26:31,860 --> 17:26:32,860
network security Now a big portion of
24193
17:26:34,200 --> 17:26:35,200
network security has to do with AAA or
24194
17:26:38,096 --> 17:26:39,096
authentication authorization and
24195
17:26:40,796 --> 17:26:41,796
accounting
24196
17:26:41,936 --> 17:26:42,936
AAA server on a network is probably one
24197
17:26:44,640 --> 17:26:45,640
of the most important things when it
24198
17:26:46,436 --> 17:26:47,436
comes to security and it's quite a bit
24199
17:26:48,296 --> 17:26:49,296
of work so in this module we're going to
24200
17:26:51,296 --> 17:26:52,296
Define and discuss these three A's
24201
17:26:54,596 --> 17:26:55,596
Authentication
24202
17:26:56,660 --> 17:26:57,660
authorization
24203
17:26:58,320 --> 17:26:59,320
and accounting in further detail so we
24204
17:27:01,680 --> 17:27:02,680
know not just what they are but how
24205
17:27:03,660 --> 17:27:04,660
they're implemented in a very general
24206
17:27:05,096 --> 17:27:06,096
way
24207
17:27:06,796 --> 17:27:07,796
authentication is the first a it's used
24208
17:27:10,080 --> 17:27:11,080
to identify the user and make sure that
24209
17:27:13,320 --> 17:27:14,320
the user is legitimate sometimes
24210
17:27:15,596 --> 17:27:16,596
attackers and Bots will try to access
24211
17:27:18,840 --> 17:27:19,840
the network or secure data by acting
24212
17:27:21,720 --> 17:27:22,720
like they're a legitimate user this is
24213
17:27:24,240 --> 17:27:25,240
where authentication comes into play
24214
17:27:26,700 --> 17:27:27,700
any secure network is going to require
24215
17:27:28,936 --> 17:27:29,936
something like a username and password
24216
17:27:31,616 --> 17:27:32,616
to log in and any data that's really
24217
17:27:34,020 --> 17:27:35,020
important or secure needs to be
24218
17:27:36,000 --> 17:27:37,000
protected now there are ways of course
24219
17:27:37,916 --> 17:27:38,916
for these attackers to gather the
24220
17:27:39,776 --> 17:27:40,776
password and username information but
24221
17:27:41,880 --> 17:27:42,880
the smart thing for us to do is to
24222
17:27:43,616 --> 17:27:44,616
change passwords for all users on a
24223
17:27:45,900 --> 17:27:46,900
network frequently probably every 30 to
24224
17:27:49,200 --> 17:27:50,200
90 days again we have to balance that
24225
17:27:52,140 --> 17:27:53,140
with how easy it is for someone to come
24226
17:27:54,240 --> 17:27:55,240
up with a new password and they're going
24227
17:27:56,400 --> 17:27:57,400
to remember the new password they come
24228
17:27:57,720 --> 17:27:58,720
up with we need to make sure that the
24229
17:27:59,456 --> 17:28:00,456
passwords are documented in some way
24230
17:28:01,860 --> 17:28:02,860
although we want to be careful again
24231
17:28:03,660 --> 17:28:04,660
because when we write them down and
24232
17:28:05,096 --> 17:28:06,096
document them that opens up another way
24233
17:28:06,900 --> 17:28:07,900
they can be stolen and we want to make
24234
17:28:08,580 --> 17:28:09,580
sure that they're all secure if an
24235
17:28:10,320 --> 17:28:11,320
attacker has an outdated password it's
24236
17:28:12,296 --> 17:28:13,296
going to do them no good so if we can
24237
17:28:15,416 --> 17:28:16,416
put this in another way
24238
17:28:16,936 --> 17:28:17,936
authentication verifies identity this is
24239
17:28:21,540 --> 17:28:22,540
sort of like you have a ID card or
24240
17:28:25,916 --> 17:28:26,916
driver's license that provides your
24241
17:28:28,616 --> 17:28:29,616
identity and authenticates you are who
24242
17:28:30,416 --> 17:28:31,416
you are one of the reasons we have
24243
17:28:32,040 --> 17:28:33,040
pictures on our driver's license or
24244
17:28:33,900 --> 17:28:34,900
government issued IDs is so that people
24245
17:28:36,060 --> 17:28:37,060
can look at it and guarantee We Are Who
24246
17:28:38,040 --> 17:28:39,040
We Are this used to be done with
24247
17:28:39,660 --> 17:28:40,660
signatures they would look at two
24248
17:28:41,456 --> 17:28:42,456
signatures make sure they were identical
24249
17:28:43,256 --> 17:28:44,256
and then we could authenticate the
24250
17:28:45,540 --> 17:28:46,540
person was actually us now we've moved
24251
17:28:47,756 --> 17:28:48,756
way past this now we can even use things
24252
17:28:49,680 --> 17:28:50,680
like fingerprints which more or less
24253
17:28:51,680 --> 17:28:52,680
authenticate that we are who we say we
24254
17:28:54,360 --> 17:28:55,360
are
24255
17:28:55,320 --> 17:28:56,320
so here is another form of
24256
17:28:56,820 --> 17:28:57,820
authentication you may have encountered
24257
17:28:58,680 --> 17:28:59,680
this one before when you're trying to
24258
17:29:00,296 --> 17:29:01,296
access things on the internet this is
24259
17:29:02,276 --> 17:29:03,276
called or looks like a captcha and it's
24260
17:29:05,340 --> 17:29:06,340
used to stop Bots from accessing secure
24261
17:29:07,796 --> 17:29:08,796
data or infiltrating someone's account
24262
17:29:09,596 --> 17:29:10,596
or making an account when we don't want
24263
17:29:11,456 --> 17:29:12,456
them to so the text in the gray box is
24264
17:29:14,456 --> 17:29:15,456
difficult to read for a bot it's
24265
17:29:16,796 --> 17:29:17,796
actually a picture and it's very
24266
17:29:19,500 --> 17:29:20,500
difficult for robots to read this and
24267
17:29:22,680 --> 17:29:23,680
know exactly what to type in
24268
17:29:24,540 --> 17:29:25,540
so because of this the captcha is
24269
17:29:26,820 --> 17:29:27,820
usually made different fonts distorted
24270
17:29:29,040 --> 17:29:30,040
text pictures Etc and it can be slightly
24271
17:29:31,740 --> 17:29:32,740
different for a human to read but not so
24272
17:29:34,200 --> 17:29:35,200
difficult for them that they can't
24273
17:29:36,180 --> 17:29:37,180
actually type it in when you type in the
24274
17:29:38,400 --> 17:29:39,400
image into here is text then you can
24275
17:29:41,520 --> 17:29:42,520
basically ensure that you are who you
24276
17:29:44,096 --> 17:29:45,096
say you are that you are a human rather
24277
17:29:46,680 --> 17:29:47,680
than a bot now authorization is the next
24278
17:29:49,860 --> 17:29:50,860
security level after authentication it's
24279
17:29:52,256 --> 17:29:53,256
the second a so once a user has been
24280
17:29:54,720 --> 17:29:55,720
determined authentic we've authenticated
24281
17:29:57,540 --> 17:29:58,540
their identity they're going to be
24282
17:29:59,640 --> 17:30:00,640
allowed onto the network but they can't
24283
17:30:01,680 --> 17:30:02,680
just have free reign and do whatever
24284
17:30:03,296 --> 17:30:04,296
they want we want to make sure that they
24285
17:30:05,700 --> 17:30:06,700
can only access specific things remember
24286
17:30:08,096 --> 17:30:09,096
that concept of least privilege well we
24287
17:30:11,040 --> 17:30:12,040
want to make sure that the person who's
24288
17:30:12,776 --> 17:30:13,776
on there is only going to access stuff
24289
17:30:14,456 --> 17:30:15,456
that they are allowed to access so
24290
17:30:16,680 --> 17:30:17,680
you're authorized to access only certain
24291
17:30:19,616 --> 17:30:20,616
things now there are users such as the
24292
17:30:23,700 --> 17:30:24,700
admin who can generally access a quiet
24293
17:30:26,276 --> 17:30:27,276
deal more but we don't want for instance
24294
17:30:28,740 --> 17:30:29,740
the administrator to have access to the
24295
17:30:30,956 --> 17:30:31,956
partner's private email in a law firm
24296
17:30:33,180 --> 17:30:34,180
and we don't want someone who works in
24297
17:30:35,580 --> 17:30:36,580
accounting to have access to marketing
24298
17:30:37,380 --> 17:30:38,380
so authorization basically provides the
24299
17:30:40,256 --> 17:30:41,256
information on what the person or the ID
24300
17:30:43,256 --> 17:30:44,256
person who has been authenticated is
24301
17:30:45,776 --> 17:30:46,776
authorized to get access to now
24302
17:30:49,916 --> 17:30:50,916
authorization procedures can stop users
24303
17:30:52,380 --> 17:30:53,380
from accessing certain datas Services
24304
17:30:54,660 --> 17:30:55,660
programs Etc and can even stop users
24305
17:30:57,480 --> 17:30:58,480
from accessing certain web pages for
24306
17:30:59,756 --> 17:31:00,756
instance we sometimes have filters that
24307
17:31:02,160 --> 17:31:03,160
make sure our kids don't access very
24308
17:31:04,860 --> 17:31:05,860
specific information unless they can
24309
17:31:06,720 --> 17:31:07,720
type in a password that would
24310
17:31:08,756 --> 17:31:09,756
authenticate that they're an adult so
24311
17:31:10,860 --> 17:31:11,860
here's an example of what a denied web
24312
17:31:13,200 --> 17:31:14,200
page might look like as you can see the
24313
17:31:15,540 --> 17:31:16,540
user is being told that an error 403 has
24314
17:31:18,000 --> 17:31:19,000
occurred other words the web page has
24315
17:31:21,416 --> 17:31:22,416
been forbidden it requires you to log on
24316
17:31:24,360 --> 17:31:25,360
and you have not logged on successfully
24317
17:31:26,400 --> 17:31:27,400
so you have not authenticated who you
24318
17:31:28,616 --> 17:31:29,616
are and therefore you are not authorized
24319
17:31:30,900 --> 17:31:31,900
to have access to specific degree of
24320
17:31:33,116 --> 17:31:34,116
information
24321
17:31:34,320 --> 17:31:35,320
now users other than the administrator
24322
17:31:36,660 --> 17:31:37,660
will most likely not be authorized to
24323
17:31:38,820 --> 17:31:39,820
run commands in the command prompt and
24324
17:31:41,220 --> 17:31:42,220
we've looked at this with a plus running
24325
17:31:42,900 --> 17:31:43,900
things in an administrator mode if the
24326
17:31:45,596 --> 17:31:46,596
user does they're probably going to
24327
17:31:46,860 --> 17:31:47,860
receive an error that looks like this
24328
17:31:48,660 --> 17:31:49,660
this command prompt has been disabled by
24329
17:31:51,180 --> 17:31:52,180
your administrator the administrator can
24330
17:31:53,340 --> 17:31:54,340
deny every other user on the network the
24331
17:31:55,380 --> 17:31:56,380
ability to use the command prompt
24332
17:31:56,936 --> 17:31:57,936
because they could do something that
24333
17:31:58,436 --> 17:31:59,436
they are not authorized to do so it's up
24334
17:32:00,900 --> 17:32:01,900
to the administrator to make sure that
24335
17:32:02,400 --> 17:32:03,400
only authorized users can access the
24336
17:32:04,860 --> 17:32:05,860
command prompt or do other things on the
24337
17:32:07,500 --> 17:32:08,500
computer or on the network for instance
24338
17:32:09,360 --> 17:32:10,360
rebooting computers accessing servers
24339
17:32:11,700 --> 17:32:12,700
and so on
24340
17:32:13,256 --> 17:32:14,256
now the final a we talked about
24341
17:32:15,860 --> 17:32:16,860
authorization and authentication is
24342
17:32:19,276 --> 17:32:20,276
accounting accounting is not the same as
24343
17:32:22,980 --> 17:32:23,980
in bookkeeping it's Accounting in the
24344
17:32:25,860 --> 17:32:26,860
sense that everything a user does while
24345
17:32:27,416 --> 17:32:28,416
on the network has to be accounted for
24346
17:32:29,276 --> 17:32:30,276
and carefully watched this is sometimes
24347
17:32:31,680 --> 17:32:32,680
also called auditing
24348
17:32:34,320 --> 17:32:35,320
another term that gets back to
24349
17:32:37,936 --> 17:32:38,936
accounting in a sort of financial sense
24350
17:32:40,436 --> 17:32:41,436
but it means something different the
24351
17:32:42,540 --> 17:32:43,540
users on a network uh can often be one
24352
17:32:45,596 --> 17:32:46,596
of the biggest of our security concerns
24353
17:32:48,180 --> 17:32:49,180
most of the time someone is going to
24354
17:32:50,400 --> 17:32:51,400
hack our network from inside rather than
24355
17:32:52,320 --> 17:32:53,320
outside and so keeping track of how
24356
17:32:54,776 --> 17:32:55,776
users spend their time is one of the
24357
17:32:56,400 --> 17:32:57,400
most important aspects of network
24358
17:32:57,720 --> 17:32:58,720
security the accounting function of the
24359
17:33:00,240 --> 17:33:01,240
AAA servers to do exactly that it
24360
17:33:02,520 --> 17:33:03,520
watches all of the users and monitors
24361
17:33:04,380 --> 17:33:05,380
their activity as well as all the
24362
17:33:06,540 --> 17:33:07,540
resources they're using these resources
24363
17:33:09,116 --> 17:33:10,116
could include stuff like bandwidth CPU
24364
17:33:11,160 --> 17:33:12,160
usage and a lot more not to mention what
24365
17:33:13,796 --> 17:33:14,796
websites they're accessing and so on now
24366
17:33:16,200 --> 17:33:17,200
some people say hey wait you're
24367
17:33:17,640 --> 17:33:18,640
infringing on my right to use the
24368
17:33:19,320 --> 17:33:20,320
internet but if you are at your company
24369
17:33:21,296 --> 17:33:22,296
using your company's internet then you
24370
17:33:23,820 --> 17:33:24,820
have signed most likely an agreement
24371
17:33:25,500 --> 17:33:26,500
saying you're only going to use it for
24372
17:33:26,756 --> 17:33:27,756
specific purposes and you've probably
24373
17:33:28,320 --> 17:33:29,320
also signed an agreement whether you
24374
17:33:30,000 --> 17:33:31,000
know it or not that allows them to
24375
17:33:31,796 --> 17:33:32,796
monitor you while you're using the
24376
17:33:33,480 --> 17:33:34,480
internet
24377
17:33:34,680 --> 17:33:35,680
so here's representation of what the
24378
17:33:37,080 --> 17:33:38,080
accounting function of AAA server does
24379
17:33:39,060 --> 17:33:40,060
it oversees everything the users are
24380
17:33:41,580 --> 17:33:42,580
doing and keeps track of what the
24381
17:33:43,200 --> 17:33:44,200
resources are those users are taking up
24382
17:33:45,296 --> 17:33:46,296
and how they're spending their time
24383
17:33:48,596 --> 17:33:49,596
now this was a short module but it
24384
17:33:50,580 --> 17:33:51,580
discussed the AAA and these are three
24385
17:33:52,616 --> 17:33:53,616
really important Concepts you need to
24386
17:33:54,360 --> 17:33:55,360
know and understand for Network plus
24387
17:33:55,860 --> 17:33:56,860
first we looked at authentication
24388
17:33:58,276 --> 17:33:59,276
authentication make sure that the
24389
17:34:01,500 --> 17:34:02,500
identity has been verified this is just
24390
17:34:04,436 --> 17:34:05,436
like in a metaphor your driver's license
24391
17:34:08,160 --> 17:34:09,160
which has a picture ID
24392
17:34:13,140 --> 17:34:14,140
next we talked about authorization this
24393
17:34:15,956 --> 17:34:16,956
is what you are allowed to do
24394
17:34:20,580 --> 17:34:21,580
this could be just like you're
24395
17:34:22,256 --> 17:34:23,256
authorized if you have your driver's
24396
17:34:23,936 --> 17:34:24,936
license and you're 21 and up in the
24397
17:34:26,880 --> 17:34:27,880
United States to drink
24398
17:34:32,220 --> 17:34:33,220
so
24399
17:34:33,720 --> 17:34:34,720
authentication is provided by the
24400
17:34:35,520 --> 17:34:36,520
driver's license you are who you say you
24401
17:34:37,140 --> 17:34:38,140
are and then authorization says whether
24402
17:34:39,060 --> 17:34:40,060
or not you're allowed to drink or even
24403
17:34:40,740 --> 17:34:41,740
drive depending on your age and a
24404
17:34:43,916 --> 17:34:44,916
variety of other circumstances finally
24405
17:34:46,820 --> 17:34:47,820
accounting is basically a log
24406
17:34:50,096 --> 17:34:51,096
of what you do
24407
17:34:53,400 --> 17:34:54,400
if you get in trouble with the law
24408
17:34:55,140 --> 17:34:56,140
that's put on a record that way if
24409
17:34:57,360 --> 17:34:58,360
you're pulled over by a policeman let's
24410
17:34:58,860 --> 17:34:59,860
say for speeding they can scan your
24411
17:35:01,080 --> 17:35:02,080
driver's license and see if you have any
24412
17:35:03,360 --> 17:35:04,360
outstanding warrants or if you've been
24413
17:35:05,220 --> 17:35:06,220
pulled over in the past in this way
24414
17:35:07,756 --> 17:35:08,756
accounting provides a background
24415
17:35:10,320 --> 17:35:11,320
information on you and can make sure
24416
17:35:12,296 --> 17:35:13,296
that we know what you're doing on the
24417
17:35:13,860 --> 17:35:14,860
network what information you're
24418
17:35:15,116 --> 17:35:16,116
accessing and also make sure when you're
24419
17:35:17,580 --> 17:35:18,580
accessing it and so on let's say that we
24420
17:35:20,040 --> 17:35:21,040
have someone rob our store at midnight
24421
17:35:23,400 --> 17:35:24,400
and the store is closed well if your
24422
17:35:26,520 --> 17:35:27,520
security card was used to get access to
24423
17:35:28,916 --> 17:35:29,916
the store then we know that either you
24424
17:35:30,956 --> 17:35:31,956
rob the store or someone who stole your
24425
17:35:33,000 --> 17:35:34,000
security card robbed your store
24426
17:35:38,900 --> 17:35:39,900
[Music]
24427
17:35:47,540 --> 17:35:48,540
thank you
24428
17:36:00,240 --> 17:36:01,240
network security system security tools
24429
17:36:04,616 --> 17:36:05,616
in the last module we talked about the
24430
17:36:06,956 --> 17:36:07,956
AAA authentication authorization and
24431
17:36:10,380 --> 17:36:11,380
accounting there's three aspects of
24432
17:36:12,840 --> 17:36:13,840
security are really important to running
24433
17:36:14,640 --> 17:36:15,640
a safe and secure network but there are
24434
17:36:16,916 --> 17:36:17,916
also some security tools and programs
24435
17:36:19,560 --> 17:36:20,560
that prove really useful when we're
24436
17:36:21,416 --> 17:36:22,416
trying to put these into action most
24437
17:36:23,640 --> 17:36:24,640
notably we're going to talk in this
24438
17:36:26,400 --> 17:36:27,400
module about firewalls and antivirus
24439
17:36:29,220 --> 17:36:30,220
software there are a lot of other tools
24440
17:36:31,140 --> 17:36:32,140
and pieces of software that we can use
24441
17:36:33,240 --> 17:36:34,240
and we'll talk about these in a bit but
24442
17:36:36,060 --> 17:36:37,060
these two come up quite a bit on the
24443
17:36:37,916 --> 17:36:38,916
network plus exam especially because
24444
17:36:39,540 --> 17:36:40,540
they're the two most prevalent that we
24445
17:36:41,340 --> 17:36:42,340
see in the field especially from a
24446
17:36:43,500 --> 17:36:44,500
consumer's point of view
24447
17:36:45,060 --> 17:36:46,060
so in this module we're going to Define
24448
17:36:47,580 --> 17:36:48,580
what a firewall is and then identify its
24449
17:36:50,520 --> 17:36:51,520
importance and how it works we're also
24450
17:36:52,740 --> 17:36:53,740
going to Define anti-virus software and
24451
17:36:55,380 --> 17:36:56,380
identify its importance and how it works
24452
17:36:58,860 --> 17:36:59,860
so let's start by talking about a
24453
17:37:00,956 --> 17:37:01,956
firewall this is something you've
24454
17:37:02,400 --> 17:37:03,400
probably heard about you might even have
24455
17:37:04,256 --> 17:37:05,256
on your computer or on your home network
24456
17:37:06,180 --> 17:37:07,180
a firewall is an essential part of any
24457
17:37:09,240 --> 17:37:10,240
secure network especially in today's day
24458
17:37:11,220 --> 17:37:12,220
and age and a network would just be at
24459
17:37:13,380 --> 17:37:14,380
risk almost constantly without it it's
24460
17:37:16,320 --> 17:37:17,320
basically a security system that serves
24461
17:37:18,540 --> 17:37:19,540
as a barrier between the local network
24462
17:37:20,820 --> 17:37:21,820
and the wide Network or VPN it analyzes
24463
17:37:24,956 --> 17:37:25,956
the data packets that are trying to
24464
17:37:26,820 --> 17:37:27,820
enter the local network and exit the
24465
17:37:29,160 --> 17:37:30,160
local network and determines whether
24466
17:37:30,900 --> 17:37:31,900
it's safe to let them in or out or not
24467
17:37:33,416 --> 17:37:34,416
in a more General sense a firewall is
24468
17:37:36,720 --> 17:37:37,720
set up between local private Network and
24469
17:37:39,596 --> 17:37:40,596
a public network like the internet so
24470
17:37:42,180 --> 17:37:43,180
internet protection is actually a large
24471
17:37:44,040 --> 17:37:45,040
part of what the firewall is used for
24472
17:37:45,956 --> 17:37:46,956
now the reason it's called a firewall is
24473
17:37:48,720 --> 17:37:49,720
because if you think about it the fire
24474
17:37:50,880 --> 17:37:51,880
is going to burn up all the bad stuff
24475
17:37:52,860 --> 17:37:53,860
but not the good stuff
24476
17:37:54,480 --> 17:37:55,480
as opposed to a brick wall which
24477
17:37:57,116 --> 17:37:58,116
wouldn't let anything in so the name
24478
17:37:59,040 --> 17:38:00,040
sort of describes what it does people
24479
17:38:01,320 --> 17:38:02,320
often establish firewalls as their main
24480
17:38:04,020 --> 17:38:05,020
line of defense from internet attacks
24481
17:38:05,880 --> 17:38:06,880
and they can be configured to not allow
24482
17:38:08,580 --> 17:38:09,580
access to certain websites as well as
24483
17:38:10,980 --> 17:38:11,980
not allow downloads from certain
24484
17:38:12,480 --> 17:38:13,480
websites or certain ports to be open
24485
17:38:14,756 --> 17:38:15,756
we'll use something called a port
24486
17:38:17,580 --> 17:38:18,580
scanner to see if there are any open
24487
17:38:20,220 --> 17:38:21,220
ports on our Network that are going to
24488
17:38:22,200 --> 17:38:23,200
let bad stuff in and what we can do is
24489
17:38:25,616 --> 17:38:26,616
actually set the firewall to allow
24490
17:38:28,740 --> 17:38:29,740
inbound
24491
17:38:30,500 --> 17:38:31,500
and outbound ports
24492
17:38:33,360 --> 17:38:34,360
now I know inbound probably makes more
24493
17:38:36,776 --> 17:38:37,776
sense than outbound but if you think
24494
17:38:39,720 --> 17:38:40,720
about it if somehow I get a virus into
24495
17:38:42,000 --> 17:38:43,000
my computer and it starts sending
24496
17:38:44,276 --> 17:38:45,276
information out I want to make sure to
24497
17:38:46,256 --> 17:38:47,256
keep that information in so that I don't
24498
17:38:48,776 --> 17:38:49,776
release any say private information
24499
17:38:51,000 --> 17:38:52,000
about my network
24500
17:38:52,436 --> 17:38:53,436
now the term firewall as I was just
24501
17:38:54,416 --> 17:38:55,416
talking about comes from the physical
24502
17:38:56,480 --> 17:38:57,480
firewalls or doors that a lot of
24503
17:38:58,560 --> 17:38:59,560
buildings contain these doors are
24504
17:39:00,900 --> 17:39:01,900
fireproof and they contain a fire to one
24505
17:39:03,660 --> 17:39:04,660
area stop it from spreading elsewhere
24506
17:39:05,936 --> 17:39:06,936
which is another way we get that term
24507
17:39:07,796 --> 17:39:08,796
they're also meant to block out fires so
24508
17:39:11,040 --> 17:39:12,040
this is what a network firewall does but
24509
17:39:13,436 --> 17:39:14,436
with threats from outside and inside of
24510
17:39:15,540 --> 17:39:16,540
the network
24511
17:39:16,320 --> 17:39:17,320
so think about a firewall if we can use
24512
17:39:18,416 --> 17:39:19,416
a metaphor as the moat and the stone
24513
17:39:21,240 --> 17:39:22,240
walls around a castle everything within
24514
17:39:23,400 --> 17:39:24,400
the castle walls is really contained and
24515
17:39:25,020 --> 17:39:26,020
localized outside the walls however
24516
17:39:27,116 --> 17:39:28,116
there's a public domain the internet
24517
17:39:29,340 --> 17:39:30,340
walls in the mode of the castle are the
24518
17:39:31,916 --> 17:39:32,916
last line of a large-scale defense
24519
17:39:33,776 --> 17:39:34,776
before an attack can infiltrate so this
24520
17:39:36,180 --> 17:39:37,180
is exactly what a firewall does it keeps
24521
17:39:37,980 --> 17:39:38,980
the public network and the private
24522
17:39:39,540 --> 17:39:40,540
Network separate from each other now the
24523
17:39:41,400 --> 17:39:42,400
castle much like a firewall does allow
24524
17:39:43,020 --> 17:39:44,020
certain things inside this is like the
24525
17:39:45,060 --> 17:39:46,060
drawbridge of the castle so when the
24526
17:39:47,400 --> 17:39:48,400
walls and the moat keep unwanted things
24527
17:39:49,320 --> 17:39:50,320
out but then things are trusted so they
24528
17:39:51,840 --> 17:39:52,840
are allowed in through the drawbridge so
24529
17:39:54,956 --> 17:39:55,956
firewalls do the same thing with packets
24530
17:39:56,520 --> 17:39:57,520
of data they only allow the ones that
24531
17:39:58,436 --> 17:39:59,436
they trust to enter the network and we
24532
17:40:00,660 --> 17:40:01,660
do this again by allowing or not
24533
17:40:03,060 --> 17:40:04,060
allowing certain ports now of course one
24534
17:40:05,220 --> 17:40:06,220
of the downsides of a firewall is it can
24535
17:40:08,040 --> 17:40:09,040
block good stuff
24536
17:40:11,520 --> 17:40:12,520
so for instance if I have Quickbooks on
24537
17:40:15,060 --> 17:40:16,060
my computer and it's trying to access
24538
17:40:16,740 --> 17:40:17,740
its download server to update the
24539
17:40:19,020 --> 17:40:20,020
program I could block the inbound Port
24540
17:40:22,680 --> 17:40:23,680
by accident through my firewall and
24541
17:40:25,860 --> 17:40:26,860
um then it wouldn't be able to get
24542
17:40:27,956 --> 17:40:28,956
updates so this is one of the issues now
24543
17:40:30,956 --> 17:40:31,956
firewalls can be either software
24544
17:40:34,380 --> 17:40:35,380
or Hardware
24545
17:40:37,140 --> 17:40:38,140
you probably without even realizing it
24546
17:40:39,060 --> 17:40:40,060
or maybe you do have a software firewall
24547
17:40:41,400 --> 17:40:42,400
built into your I OS
24548
17:40:45,116 --> 17:40:46,116
so if you have Windows 7 Windows 8
24549
17:40:47,456 --> 17:40:48,456
Windows Vista then you actually have a
24550
17:40:49,860 --> 17:40:50,860
firewall built in now you could also
24551
17:40:52,320 --> 17:40:53,320
have a hardware firewall which if we're
24552
17:40:55,140 --> 17:40:56,140
talking about your home network is
24553
17:40:57,180 --> 17:40:58,180
generally built into your Soho router
24554
17:40:59,276 --> 17:41:00,276
that's right your Soho router contains a
24555
17:41:02,756 --> 17:41:03,756
firewall built in and will allow or not
24556
17:41:04,860 --> 17:41:05,860
allow certain ports to come in this
24557
17:41:07,200 --> 17:41:08,200
awfuls us
24558
17:41:08,520 --> 17:41:09,520
two levels
24559
17:41:10,796 --> 17:41:11,796
of security
24560
17:41:13,616 --> 17:41:14,616
one through the hardware and once it
24561
17:41:15,720 --> 17:41:16,720
gets through indoor Network then we have
24562
17:41:17,456 --> 17:41:18,456
one on our computer
24563
17:41:19,560 --> 17:41:20,560
now like we said before firewalls are
24564
17:41:22,560 --> 17:41:23,560
mostly used to block uh attacks from the
24565
17:41:26,040 --> 17:41:27,040
outside but it's not the only use see
24566
17:41:28,860 --> 17:41:29,860
there are quite a few actually as we
24567
17:41:30,596 --> 17:41:31,596
already talked about they keep attacks
24568
17:41:32,640 --> 17:41:33,640
out by monitoring everything that tries
24569
17:41:34,616 --> 17:41:35,616
to enter if something isn't trustworthy
24570
17:41:36,956 --> 17:41:37,956
it's not going to let it through now
24571
17:41:38,756 --> 17:41:39,756
though this might be the most recognized
24572
17:41:40,560 --> 17:41:41,560
use there are some other important
24573
17:41:42,000 --> 17:41:43,000
aspects that we want to talk about for
24574
17:41:44,700 --> 17:41:45,700
instance the firewall acts as a barrier
24575
17:41:46,616 --> 17:41:47,616
which not only keeps things out but it
24576
17:41:48,360 --> 17:41:49,360
makes sure that important things inside
24577
17:41:50,276 --> 17:41:51,276
the network don't get out which in
24578
17:41:52,680 --> 17:41:53,680
effect keeps the data secure this is
24579
17:41:54,720 --> 17:41:55,720
what I was talking about without bound
24580
17:41:58,140 --> 17:41:59,140
ports
24581
17:42:00,240 --> 17:42:01,240
for example if secure data is being
24582
17:42:03,480 --> 17:42:04,480
accessed and taken from someone on the
24583
17:42:05,096 --> 17:42:06,096
outside then we can make sure that the
24584
17:42:08,096 --> 17:42:09,096
data can't get out through our Network
24585
17:42:10,020 --> 17:42:11,020
it's going to be stopped just like
24586
17:42:11,456 --> 17:42:12,456
containing the fire within the building
24587
17:42:13,860 --> 17:42:14,860
this is really important to businesses
24588
17:42:15,840 --> 17:42:16,840
and organizations where data really
24589
17:42:17,880 --> 17:42:18,880
equals money or more than money now for
24590
17:42:20,276 --> 17:42:21,276
individuals it can help secure important
24591
17:42:22,916 --> 17:42:23,916
information like your social security
24592
17:42:24,296 --> 17:42:25,296
number credit card information
24593
17:42:26,096 --> 17:42:27,096
Etc these aren't things that you want in
24594
17:42:28,436 --> 17:42:29,436
the hands of attackers so a firewall can
24595
17:42:30,720 --> 17:42:31,720
actually prevent these problems that an
24596
17:42:32,400 --> 17:42:33,400
attack might cause
24597
17:42:34,436 --> 17:42:35,436
just as a matter of example I'm here in
24598
17:42:36,840 --> 17:42:37,840
Windows 7 and let's go ahead and check
24599
17:42:39,180 --> 17:42:40,180
out the Windows firewall
24600
17:42:41,276 --> 17:42:42,276
now I actually have two options here one
24601
17:42:43,080 --> 17:42:44,080
is far with Advanced security and the
24602
17:42:44,880 --> 17:42:45,880
plain old Windows firewall
24603
17:42:46,680 --> 17:42:47,680
if we go into plan we'll win this far
24604
17:42:48,296 --> 17:42:49,296
well you can see the firewall is on and
24605
17:42:51,000 --> 17:42:52,000
it's working on this network and if I go
24606
17:42:53,636 --> 17:42:54,636
over here I can choose whether or not to
24607
17:42:55,980 --> 17:42:56,980
turn the firewall off or on
24608
17:42:58,616 --> 17:42:59,616
now if we go to those advanced settings
24609
17:43:00,180 --> 17:43:01,180
I referred to earlier
24610
17:43:02,580 --> 17:43:03,580
you can see that I have inbound rules
24611
17:43:04,320 --> 17:43:05,320
and outbound rules
24612
17:43:06,480 --> 17:43:07,480
there are inbound rules that allow and
24613
17:43:09,116 --> 17:43:10,116
disallow certain information
24614
17:43:11,276 --> 17:43:12,276
for instance this rule which says file
24615
17:43:13,380 --> 17:43:14,380
and print sharing Echo request allows
24616
17:43:15,956 --> 17:43:16,956
the connection to be made for icmp
24617
17:43:18,596 --> 17:43:19,596
packets which is basically for Ping now
24618
17:43:21,296 --> 17:43:22,296
I can choose to disable a rule or create
24619
17:43:24,480 --> 17:43:25,480
a new rule for instance if I have a
24620
17:43:26,880 --> 17:43:27,880
specific program or Port that I know
24621
17:43:28,980 --> 17:43:29,980
needs to have access
24622
17:43:31,436 --> 17:43:32,436
you remember the ports that we talked
24623
17:43:33,416 --> 17:43:34,416
about previously and this is an example
24624
17:43:35,756 --> 17:43:36,756
of how you would use that now I also
24625
17:43:38,160 --> 17:43:39,160
have outbound rules so for instance
24626
17:43:40,200 --> 17:43:41,200
instead of allowing information into the
24627
17:43:42,240 --> 17:43:43,240
system I want to talk about information
24628
17:43:43,616 --> 17:43:44,616
I want to let out so for instance
24629
17:43:46,136 --> 17:43:47,136
Windows Media Player has a number of
24630
17:43:48,720 --> 17:43:49,720
rules that are here notice that none of
24631
17:43:50,820 --> 17:43:51,820
them are enabled
24632
17:43:52,200 --> 17:43:53,200
so if we were to check this one out for
24633
17:43:54,540 --> 17:43:55,540
instance it says there's an outbound
24634
17:43:56,340 --> 17:43:57,340
rule to allow the sharing service for a
24635
17:44:00,000 --> 17:44:01,000
Windows Media Player now I could enable
24636
17:44:02,340 --> 17:44:03,340
this and that would allow it to occur
24637
17:44:04,080 --> 17:44:05,080
but because it is disabled to this
24638
17:44:06,116 --> 17:44:07,116
moment it's actually not going to allow
24639
17:44:07,740 --> 17:44:08,740
any of that information out so this is
24640
17:44:10,020 --> 17:44:11,020
how very quickly
24641
17:44:12,060 --> 17:44:13,060
the firewall works on your software but
24642
17:44:15,296 --> 17:44:16,296
it would also work the same way if you
24643
17:44:16,860 --> 17:44:17,860
had a hardware device too you can also
24644
17:44:19,320 --> 17:44:20,320
have it monitor what's going on so for
24645
17:44:23,040 --> 17:44:24,040
instance this is telling me that the
24646
17:44:24,596 --> 17:44:25,596
inbound connections aren't matching a
24647
17:44:26,880 --> 17:44:27,880
rule so that I could go in and check out
24648
17:44:28,916 --> 17:44:29,916
exactly what that is
24649
17:44:30,956 --> 17:44:31,956
and it's also telling me I can see all
24650
17:44:33,540 --> 17:44:34,540
the active rules and so on that are
24651
17:44:36,660 --> 17:44:37,660
going on here now here's an example of
24652
17:44:38,820 --> 17:44:39,820
what a fire mole might do as you can see
24653
17:44:40,916 --> 17:44:41,916
it's separating the WAN which usually
24654
17:44:45,956 --> 17:44:46,956
would be shown by a cloud
24655
17:44:51,480 --> 17:44:52,480
which we could call the internet
24656
17:44:54,900 --> 17:44:55,900
and the users on the WAN have to be
24657
17:44:57,240 --> 17:44:58,240
authenticated and allowed before their
24658
17:44:59,580 --> 17:45:00,580
go past this firewall this is useful
24659
17:45:02,160 --> 17:45:03,160
because an attack could very possibly
24660
17:45:03,660 --> 17:45:04,660
infiltrate the WAN and try to get access
24661
17:45:05,820 --> 17:45:06,820
to the local network but if they're not
24662
17:45:07,860 --> 17:45:08,860
recognized not given permission by the
24663
17:45:09,540 --> 17:45:10,540
firewall they're not going to be able to
24664
17:45:10,560 --> 17:45:11,560
enter the land sometimes what we'll also
24665
17:45:13,020 --> 17:45:14,020
have is a separate Network that they'll
24666
17:45:14,820 --> 17:45:15,820
be allowed into
24667
17:45:16,200 --> 17:45:17,200
that's sort of not between the firewall
24668
17:45:18,660 --> 17:45:19,660
in some cases even if I erase this we'll
24669
17:45:21,180 --> 17:45:22,180
actually have
24670
17:45:22,680 --> 17:45:23,680
two firewalls
24671
17:45:26,276 --> 17:45:27,276
one which allows a lot of stuff in and
24672
17:45:28,916 --> 17:45:29,916
creates sort of a demilitarized zone
24673
17:45:32,456 --> 17:45:33,456
which then we can either put a test
24674
17:45:35,636 --> 17:45:36,636
server on or a test computer sometimes
24675
17:45:38,040 --> 17:45:39,040
we'll call this
24676
17:45:39,240 --> 17:45:40,240
a Honeypot will allow a lot of stuff in
24677
17:45:42,540 --> 17:45:43,540
through the first firewall
24678
17:45:44,400 --> 17:45:45,400
and then when the hackers find stuff
24679
17:45:46,916 --> 17:45:47,916
they're going to start attacking this
24680
17:45:48,180 --> 17:45:49,180
Honeypot
24681
17:45:49,256 --> 17:45:50,256
Honeypot being sort of like bees go into
24682
17:45:51,660 --> 17:45:52,660
honey we can then see what they're
24683
17:45:53,756 --> 17:45:54,756
looking at what they're trying to get
24684
17:45:55,080 --> 17:45:56,080
access to Etc and this gives us a sense
24685
17:45:57,660 --> 17:45:58,660
of testing the network security
24686
17:45:59,636 --> 17:46:00,636
then once they get into the
24687
17:46:01,500 --> 17:46:02,500
demilitarized zone they have to pass
24688
17:46:03,180 --> 17:46:04,180
another set of protocols to get in to
24689
17:46:05,456 --> 17:46:06,456
our Network and as we mentioned there
24690
17:46:07,740 --> 17:46:08,740
might also be firewalls
24691
17:46:10,680 --> 17:46:11,680
on each one of these computers if you
24692
17:46:13,796 --> 17:46:14,796
can pardon my awful drawing
24693
17:46:16,796 --> 17:46:17,796
so we're going to have software
24694
17:46:18,540 --> 17:46:19,540
firewalls just like we have Hardware
24695
17:46:20,040 --> 17:46:21,040
firewalls in fact this might be a device
24696
17:46:23,880 --> 17:46:24,880
or it could be a server
24697
17:46:26,636 --> 17:46:27,636
with firewall software built in
24698
17:46:29,340 --> 17:46:30,340
now anti-virus software is everywhere
24699
17:46:31,980 --> 17:46:32,980
and there are more companies and
24700
17:46:33,180 --> 17:46:34,180
softwares that protect against attacks
24701
17:46:35,456 --> 17:46:36,456
than you can count some of the ones you
24702
17:46:37,380 --> 17:46:38,380
might even know are for instance McAfee
24703
17:46:41,520 --> 17:46:42,520
and Norton two big ones there's also AVG
24704
17:46:45,596 --> 17:46:46,596
which offers a free one Trend and the
24705
17:46:48,956 --> 17:46:49,956
list goes on and on and on now in
24706
17:46:50,820 --> 17:46:51,820
general most of the software is pretty
24707
17:46:52,436 --> 17:46:53,436
similar and they all do the same types
24708
17:46:54,360 --> 17:46:55,360
of things some more expensive than the
24709
17:46:55,860 --> 17:46:56,860
others some are more for Enterprises
24710
17:46:58,320 --> 17:46:59,320
they have a server set up so you could
24711
17:47:00,360 --> 17:47:01,360
monitor your entire network without
24712
17:47:02,520 --> 17:47:03,520
having to go to each individual computer
24713
17:47:04,796 --> 17:47:05,796
but in effect they all do the same thing
24714
17:47:07,136 --> 17:47:08,136
so although a firewall is a really good
24715
17:47:09,060 --> 17:47:10,060
resource against attacks there's nothing
24716
17:47:10,436 --> 17:47:11,436
it can do once the attack has already
24717
17:47:13,200 --> 17:47:14,200
taken place once the system is already
24718
17:47:16,616 --> 17:47:17,616
infiltrated so attacks are not always
24719
17:47:19,020 --> 17:47:20,020
obvious and sometimes attacks are so
24720
17:47:21,060 --> 17:47:22,060
subtle they happen right under our noses
24721
17:47:22,860 --> 17:47:23,860
you might not even know you have a virus
24722
17:47:25,080 --> 17:47:26,080
until it's already done damage so even
24723
17:47:27,360 --> 17:47:28,360
though firewall protects the attack it
24724
17:47:29,400 --> 17:47:30,400
can't get rid of the malicious things
24725
17:47:30,596 --> 17:47:31,596
that have gotten through this is where
24726
17:47:32,096 --> 17:47:33,096
antivirus comes in
24727
17:47:34,136 --> 17:47:35,136
this software has many functions one of
24728
17:47:37,020 --> 17:47:38,020
the more important ones is that it
24729
17:47:38,456 --> 17:47:39,456
offers real-time protection the software
24730
17:47:41,456 --> 17:47:42,456
is constantly on the lookout for attacks
24731
17:47:43,080 --> 17:47:44,080
and malicious things software that
24732
17:47:44,456 --> 17:47:45,456
doesn't look right and firewalls merely
24733
17:47:46,500 --> 17:47:47,500
block the attacks whereas antivirus
24734
17:47:48,296 --> 17:47:49,296
software will go after an attack before
24735
17:47:50,520 --> 17:47:51,520
it goes before it can get through the
24736
17:47:53,340 --> 17:47:54,340
firewall now uh this software can also
24737
17:47:56,400 --> 17:47:57,400
scan for viruses and remove them once
24738
17:47:58,380 --> 17:47:59,380
they're found now sometimes this can be
24739
17:48:00,116 --> 17:48:01,116
tricky because just like if I install
24740
17:48:03,180 --> 17:48:04,180
the antivirus software
24741
17:48:05,936 --> 17:48:06,936
after
24742
17:48:09,776 --> 17:48:10,776
the virus has infected my system the
24743
17:48:11,936 --> 17:48:12,936
viruses might not be found by the virus
24744
17:48:13,860 --> 17:48:14,860
software it's also going to look at
24745
17:48:16,380 --> 17:48:17,380
suspicious files and data and place them
24746
17:48:19,020 --> 17:48:20,020
into what we call the quarantine
24747
17:48:21,776 --> 17:48:22,776
the quarantine just like the name is a
24748
17:48:24,660 --> 17:48:25,660
place where we're going to put all those
24749
17:48:25,740 --> 17:48:26,740
files that might be infected and that
24750
17:48:27,840 --> 17:48:28,840
way we can make sure that we can look
24751
17:48:29,880 --> 17:48:30,880
over them as an administrators see if
24752
17:48:31,500 --> 17:48:32,500
they're infected and either delete them
24753
17:48:33,060 --> 17:48:34,060
or bring them back into the network
24754
17:48:35,880 --> 17:48:36,880
finally antivirus software is going to
24755
17:48:37,740 --> 17:48:38,740
update itself constantly if you imagine
24756
17:48:40,980 --> 17:48:41,980
that viruses and hackers are constantly
24757
17:48:43,860 --> 17:48:44,860
doing their work to keep everything up
24758
17:48:45,540 --> 17:48:46,540
to date well then you probably have an
24759
17:48:47,756 --> 17:48:48,756
understanding that we need to keep the
24760
17:48:50,276 --> 17:48:51,276
antivirus software up to date just like
24761
17:48:52,616 --> 17:48:53,616
every year we have to create new uh
24762
17:48:55,796 --> 17:48:56,796
vaccines for the flu and so on we want
24763
17:48:58,980 --> 17:48:59,980
to make sure that the antivirus software
24764
17:49:00,480 --> 17:49:01,480
is kept to date this is generally what's
24765
17:49:02,580 --> 17:49:03,580
referred to as data files or dat files
24766
17:49:05,700 --> 17:49:06,700
and you used to have to download these
24767
17:49:07,796 --> 17:49:08,796
off the internet and install them now
24768
17:49:09,956 --> 17:49:10,956
this happens usually automatically just
24769
17:49:12,840 --> 17:49:13,840
like Windows update but we need to make
24770
17:49:15,360 --> 17:49:16,360
sure the setting is correct so that it
24771
17:49:17,456 --> 17:49:18,456
allows itself to be updated
24772
17:49:19,136 --> 17:49:20,136
automatically
24773
17:49:21,840 --> 17:49:22,840
so just to recap we talked about a
24774
17:49:24,416 --> 17:49:25,416
firewall remember it works with inbound
24775
17:49:29,480 --> 17:49:30,480
and outbound ports it's going to allow
24776
17:49:33,000 --> 17:49:34,000
some good things and good things out but
24777
17:49:35,936 --> 17:49:36,936
it keeps the ins the bad stuff out and
24778
17:49:39,116 --> 17:49:40,116
the good stuff in
24779
17:49:40,616 --> 17:49:41,616
we're also going to identify we also
24780
17:49:42,720 --> 17:49:43,720
identified rather its importance talking
24781
17:49:44,936 --> 17:49:45,936
about how we can have several Hardware
24782
17:49:49,436 --> 17:49:50,436
and software firewall Solutions
24783
17:49:52,860 --> 17:49:53,860
and again we might have to manually edit
24784
17:49:56,220 --> 17:49:57,220
the inbound and outbound ports
24785
17:49:59,936 --> 17:50:00,936
to allow for instance a software program
24786
17:50:02,636 --> 17:50:03,636
that uses its own port to get out and
24787
17:50:04,616 --> 17:50:05,616
get updates one of that software that
24788
17:50:06,596 --> 17:50:07,596
might need to go out and get updates
24789
17:50:07,560 --> 17:50:08,560
would be our antivirus software which is
24790
17:50:09,720 --> 17:50:10,720
what we talked about this is software
24791
17:50:11,520 --> 17:50:12,520
that does not it can prevent
24792
17:50:14,340 --> 17:50:15,340
an attack but it can sort of take over
24793
17:50:17,520 --> 17:50:18,520
from where the firewall stops whereas a
24794
17:50:21,000 --> 17:50:22,000
firewall can't stop it once it's already
24795
17:50:22,740 --> 17:50:23,740
started an antivirus software program
24796
17:50:24,900 --> 17:50:25,900
can go a little more in depth it has to
24797
17:50:27,480 --> 17:50:28,480
be kept up to date
24798
17:50:30,776 --> 17:50:31,776
and it might not necessarily be able to
24799
17:50:33,660 --> 17:50:34,660
remove the virus but it will put the
24800
17:50:35,936 --> 17:50:36,936
virus and the files that it has infected
24801
17:50:38,220 --> 17:50:39,220
into a quarantine
24802
17:50:41,040 --> 17:50:42,040
so that's really what's important about
24803
17:50:42,956 --> 17:50:43,956
it and if you've been working on a
24804
17:50:44,756 --> 17:50:45,756
computer at all in the past 15 or 20
24805
17:50:46,380 --> 17:50:47,380
years you've definitely had to use this
24806
17:50:48,240 --> 17:50:49,240
and nowadays actually Windows requires
24807
17:50:53,756 --> 17:50:54,756
that you have a virus scan on or it will
24808
17:50:56,580 --> 17:50:57,580
actually bother you in the notification
24809
17:50:58,136 --> 17:50:59,136
center quite often
24810
17:51:00,180 --> 17:51:01,180
so now that we've talked about this
24811
17:51:01,916 --> 17:51:02,916
let's end by talking about how we can
24812
17:51:04,916 --> 17:51:05,916
protect our data in a very raw sense
24813
17:51:07,136 --> 17:51:08,136
called encryption and cryptography
24814
17:51:12,760 --> 17:51:13,760
[Music]
24815
17:51:32,720 --> 17:51:33,720
network security encryption and
24816
17:51:36,000 --> 17:51:37,000
cryptography 101
24817
17:51:38,456 --> 17:51:39,456
so to round up our discussion of network
24818
17:51:41,160 --> 17:51:42,160
security I want to talk about the way
24819
17:51:43,256 --> 17:51:44,256
that we secure data at the source and
24820
17:51:46,136 --> 17:51:47,136
this gets to basically encoding the data
24821
17:51:48,900 --> 17:51:49,900
that we send so even if it's captured or
24822
17:51:52,080 --> 17:51:53,080
sniffed we can't allow the hackers to
24823
17:51:54,840 --> 17:51:55,840
figure out what it is that we were
24824
17:51:56,096 --> 17:51:57,096
sending in the first place and so this
24825
17:51:58,136 --> 17:51:59,136
gets to encryption and cryptography just
24826
17:52:00,240 --> 17:52:01,240
like code breaking from World War II or
24827
17:52:03,776 --> 17:52:04,776
from our military when they would send
24828
17:52:06,416 --> 17:52:07,416
encrypted messages
24829
17:52:08,400 --> 17:52:09,400
and because this is a pretty in-depth
24830
17:52:11,040 --> 17:52:12,040
topic we're only going to cover this
24831
17:52:12,596 --> 17:52:13,596
broadly so first we're going to Define
24832
17:52:14,700 --> 17:52:15,700
and discuss cryptography
24833
17:52:17,276 --> 17:52:18,276
and then we're going to Define and
24834
17:52:18,720 --> 17:52:19,720
discuss encryption including the
24835
17:52:21,116 --> 17:52:22,116
difference between plain text and
24836
17:52:22,860 --> 17:52:23,860
ciphertext one being the way that text
24837
17:52:26,340 --> 17:52:27,340
is sent if we don't add any encryption
24838
17:52:28,740 --> 17:52:29,740
and the other one if we do add
24839
17:52:30,596 --> 17:52:31,596
encryption and then public and private
24840
17:52:33,416 --> 17:52:34,416
Keys sort of like decoder rings for how
24841
17:52:36,720 --> 17:52:37,720
we can read the ciphertext the public
24842
17:52:39,296 --> 17:52:40,296
and private part comes about in the way
24843
17:52:42,060 --> 17:52:43,060
that we have the sender and the receiver
24844
17:52:45,136 --> 17:52:46,136
decode and encrypt certain messages
24845
17:52:48,900 --> 17:52:49,900
finally we'll identify examples of both
24846
17:52:51,660 --> 17:52:52,660
and how they work now this entire
24847
17:52:54,380 --> 17:52:55,380
subject gets a lot more in depth if you
24848
17:52:56,880 --> 17:52:57,880
go into Security Plus and the CompTIA
24849
17:52:58,860 --> 17:52:59,860
Security Plus certification so here
24850
17:53:01,080 --> 17:53:02,080
we're just covering this in a sort of
24851
17:53:02,456 --> 17:53:03,456
very broad sense there are people whose
24852
17:53:04,860 --> 17:53:05,860
entire jobs it is to Simply deal with
24853
17:53:07,560 --> 17:53:08,560
this aspect of networking
24854
17:53:09,840 --> 17:53:10,840
so in a very general sense cryptography
24855
17:53:12,776 --> 17:53:13,776
is the practice of securing information
24856
17:53:15,320 --> 17:53:16,320
using codes in order to keep adversaries
24857
17:53:18,840 --> 17:53:19,840
or hackers or outside folks from
24858
17:53:20,756 --> 17:53:21,756
understanding it now the word adversary
24859
17:53:23,480 --> 17:53:24,480
generally means an enemy or an opponent
24860
17:53:26,400 --> 17:53:27,400
in this case it just means someone who
24861
17:53:28,436 --> 17:53:29,436
would want to intercept the information
24862
17:53:30,180 --> 17:53:31,180
you're sending it's very likely that
24863
17:53:32,820 --> 17:53:33,820
this adversary is your enemy
24864
17:53:34,980 --> 17:53:35,980
quote-unquote such as a computer hacker
24865
17:53:37,500 --> 17:53:38,500
and although cryptography is not only
24866
17:53:40,740 --> 17:53:41,740
used in Computing in fact it's been used
24867
17:53:44,400 --> 17:53:45,400
throughout the world even in the United
24868
17:53:45,660 --> 17:53:46,660
States and Military Etc it's used quite
24869
17:53:48,660 --> 17:53:49,660
a bit here in networking and it's used a
24870
17:53:51,596 --> 17:53:52,596
lot in how we package data into packets
24871
17:53:54,720 --> 17:53:55,720
so cryptography simply means writing
24872
17:53:57,416 --> 17:53:58,416
speaking communicating in code this
24873
17:54:00,000 --> 17:54:01,000
practice dates back to the time of
24874
17:54:01,560 --> 17:54:02,560
Julius Caesar and quite possibly even
24875
17:54:03,596 --> 17:54:04,596
earlier than that Caesar used something
24876
17:54:05,700 --> 17:54:06,700
that's referred to as the Caesar Cipher
24877
17:54:08,756 --> 17:54:09,756
which we'll look at in just a second a
24878
17:54:10,860 --> 17:54:11,860
cipher is a way to encode and decode
24879
17:54:13,616 --> 17:54:14,616
data so Caesar used it to send messages
24880
17:54:16,080 --> 17:54:17,080
and commands that needed to remain
24881
17:54:17,820 --> 17:54:18,820
secret we were also used it in the
24882
17:54:20,400 --> 17:54:21,400
United States during World War II uh the
24883
17:54:22,860 --> 17:54:23,860
Japanese used there have been a whole
24884
17:54:24,240 --> 17:54:25,240
bunch of movies about this cryptography
24885
17:54:26,456 --> 17:54:27,456
and ciphers play a large role in
24886
17:54:28,080 --> 17:54:29,080
communication especially when we don't
24887
17:54:29,400 --> 17:54:30,400
want our enemies to know what we're
24888
17:54:30,540 --> 17:54:31,540
talking about
24889
17:54:31,680 --> 17:54:32,680
this was true all over the world people
24890
17:54:34,136 --> 17:54:35,136
began speaking over the radio writing in
24891
17:54:36,060 --> 17:54:37,060
codes in order to keep information
24892
17:54:37,200 --> 17:54:38,200
secure so a language like the English
24893
17:54:40,200 --> 17:54:41,200
language might be a form of cryptography
24894
17:54:43,740 --> 17:54:44,740
to someone who speaks Spanish if they
24895
17:54:46,560 --> 17:54:47,560
don't understand the language However
24896
17:54:48,480 --> 17:54:49,480
the fact that there is a dictionary out
24897
17:54:51,180 --> 17:54:52,180
there that translates everything for
24898
17:54:52,796 --> 17:54:53,796
them means that the code is pretty easy
24899
17:54:54,720 --> 17:54:55,720
to break so what we're really talking
24900
17:54:56,400 --> 17:54:57,400
about and what the Caesar code did for
24901
17:54:58,200 --> 17:54:59,200
instance is replace
24902
17:55:00,240 --> 17:55:01,240
um every a went down three numbers and
24903
17:55:03,776 --> 17:55:04,776
replace it with a d so whenever you saw
24904
17:55:06,116 --> 17:55:07,116
for instance uh the word
24905
17:55:08,880 --> 17:55:09,880
Apple
24906
17:55:10,436 --> 17:55:11,436
we would add
24907
17:55:12,776 --> 17:55:13,776
plus 3 would be our code and so if we
24908
17:55:16,020 --> 17:55:17,020
went down three if we wrote this out
24909
17:55:17,936 --> 17:55:18,936
from a is b c d
24910
17:55:21,000 --> 17:55:22,000
from p is QRS
24911
17:55:25,020 --> 17:55:26,020
from L is M N O and from E is fgh so if
24912
17:55:30,840 --> 17:55:31,840
we were to write Apple in the Caesar
24913
17:55:33,000 --> 17:55:34,000
code this is what it would look like and
24914
17:55:35,276 --> 17:55:36,276
that's because if we went back three for
24915
17:55:37,256 --> 17:55:38,256
each of these we would get the word
24916
17:55:39,116 --> 17:55:40,116
Apple now there was only one code that
24917
17:55:42,360 --> 17:55:43,360
remained unbreakable in World War II and
24918
17:55:45,060 --> 17:55:46,060
it was used uh by the US so the Japanese
24919
17:55:47,520 --> 17:55:48,520
could not intercept messages that were
24920
17:55:49,380 --> 17:55:50,380
being sent the US actually Enlisted the
24921
17:55:51,540 --> 17:55:52,540
help this is a really interesting fact
24922
17:55:53,040 --> 17:55:54,040
of Navajo Native Americans in order to
24923
17:55:57,180 --> 17:55:58,180
help them transmit messages and these
24924
17:55:59,160 --> 17:56:00,160
Navajo code talkers spoke a language
24925
17:56:01,560 --> 17:56:02,560
that was so dead and was only spoken by
24926
17:56:03,840 --> 17:56:04,840
very few people that every U.S major
24927
17:56:06,720 --> 17:56:07,720
base had a Navajo code Docker with them
24928
17:56:09,720 --> 17:56:10,720
and they would translate messages and
24929
17:56:12,000 --> 17:56:13,000
send them over to each other it was
24930
17:56:13,796 --> 17:56:14,796
never cracked by the Japanese there was
24931
17:56:15,540 --> 17:56:16,540
even a movie about this so this is how
24932
17:56:19,200 --> 17:56:20,200
cryptography worked right if we have a
24933
17:56:21,416 --> 17:56:22,416
language that someone doesn't understand
24934
17:56:22,616 --> 17:56:23,616
then that is a form of cryptography fee
24935
17:56:25,560 --> 17:56:26,560
there's no dictionary in this case of
24936
17:56:27,660 --> 17:56:28,660
the Caesar code all right this is what
24937
17:56:30,240 --> 17:56:31,240
he did
24938
17:56:32,340 --> 17:56:33,340
and uh if we want to look a little bit
24939
17:56:34,560 --> 17:56:35,560
closer at how that worked we can see the
24940
17:56:36,840 --> 17:56:37,840
Caesar Cipher basically every letter in
24941
17:56:39,956 --> 17:56:40,956
this case we're going back three
24942
17:56:43,560 --> 17:56:44,560
uh it was in the original text and then
24943
17:56:46,080 --> 17:56:47,080
you would go back and so a became x b
24944
17:56:49,500 --> 17:56:50,500
became Y and so on what we did earlier
24945
17:56:51,416 --> 17:56:52,416
was actually go forward three so
24946
17:56:53,636 --> 17:56:54,636
whatever it was we could figure out what
24947
17:56:56,700 --> 17:56:57,700
the code would be simply by minusing or
24948
17:56:59,580 --> 17:57:00,580
adding three so for instance if we were
24949
17:57:02,220 --> 17:57:03,220
to write ABC right now in the Caesar
24950
17:57:04,740 --> 17:57:05,740
code with a minus three it would turn
24951
17:57:06,480 --> 17:57:07,480
into x y z this is a really simple code
24952
17:57:09,240 --> 17:57:10,240
which is why it's not used anymore now
24953
17:57:11,520 --> 17:57:12,520
we have a much more
24954
17:57:13,380 --> 17:57:14,380
intense codes that are used now compared
24955
17:57:16,980 --> 17:57:17,980
to cryptography encryption is the
24956
17:57:18,660 --> 17:57:19,660
practice of putting important and
24957
17:57:19,860 --> 17:57:20,860
confidential information into a code
24958
17:57:22,500 --> 17:57:23,500
that can't be accessed by unauthorized
24959
17:57:24,720 --> 17:57:25,720
users encryption is basically the use of
24960
17:57:28,020 --> 17:57:29,020
cryptography as you can see by the word
24961
17:57:30,956 --> 17:57:31,956
here
24962
17:57:32,276 --> 17:57:33,276
so encryption is usually used for
24963
17:57:34,560 --> 17:57:35,560
information that we want to keep as a
24964
17:57:36,240 --> 17:57:37,240
secret or that's someone we we want to
24965
17:57:38,456 --> 17:57:39,456
make sure is not going to get out to
24966
17:57:39,900 --> 17:57:40,900
other people now a lot of times we're
24967
17:57:41,756 --> 17:57:42,756
going to use encryption with not just
24968
17:57:42,840 --> 17:57:43,840
regulate and we're going to add higher
24969
17:57:45,060 --> 17:57:46,060
end encryption to stuff like credit card
24970
17:57:46,616 --> 17:57:47,616
numbers Social Security numbers Bank
24971
17:57:48,296 --> 17:57:49,296
information
24972
17:57:49,380 --> 17:57:50,380
Etc
24973
17:57:50,160 --> 17:57:51,160
so encryption is really just a part of
24974
17:57:52,320 --> 17:57:53,320
cryptography cryptography is broader
24975
17:57:54,840 --> 17:57:55,840
encryption happens with the data that is
24976
17:57:57,360 --> 17:57:58,360
being sent through a network so like
24977
17:57:59,340 --> 17:58:00,340
cryptography and encryption encrypted
24978
17:58:01,916 --> 17:58:02,916
message is coded and appears to be
24979
17:58:04,680 --> 17:58:05,680
complete nonsense to someone who doesn't
24980
17:58:06,416 --> 17:58:07,416
know what the code is now the data is
24981
17:58:09,360 --> 17:58:10,360
run through an algorithm in order to
24982
17:58:11,160 --> 17:58:12,160
place encryption on it then on the other
24983
17:58:13,680 --> 17:58:14,680
side the reverse of the algorithm is
24984
17:58:15,776 --> 17:58:16,776
used to decrypt the data and an
24985
17:58:18,540 --> 17:58:19,540
algorithm is a mathematical equation
24986
17:58:20,400 --> 17:58:21,400
that can be used for several different
24987
17:58:21,660 --> 17:58:22,660
things for instance in the Caesar code
24988
17:58:23,240 --> 17:58:24,240
the mathematical equation if we had X as
24989
17:58:28,680 --> 17:58:29,680
the uh plain text
24990
17:58:31,616 --> 17:58:32,616
and Y as the cipher text or the text
24991
17:58:35,220 --> 17:58:36,220
that had a code added to it we could say
24992
17:58:37,740 --> 17:58:38,740
that if we took the code it would equal
24993
17:58:40,320 --> 17:58:41,320
y plus 3. so if we had x y z and that
24994
17:58:45,180 --> 17:58:46,180
was our code
24995
17:58:47,700 --> 17:58:48,700
and we added 3 to that
24996
17:58:51,596 --> 17:58:52,596
then we would end up with a b c and so
24997
17:58:55,136 --> 17:58:56,136
that's how that all sort of works now
24998
17:58:57,416 --> 17:58:58,416
encryption in an algorithms are a lot
24999
17:58:59,880 --> 17:59:00,880
more intense than the one I just sort of
25000
17:59:01,860 --> 17:59:02,860
laid out and they're used not only to
25001
17:59:03,720 --> 17:59:04,720
code data but also to decrypt it or
25002
17:59:06,296 --> 17:59:07,296
unencode it in a way that can't be read
25003
17:59:08,340 --> 17:59:09,340
by our adversaries or people outside of
25004
17:59:11,456 --> 17:59:12,456
of ourselves
25005
17:59:13,740 --> 17:59:14,740
so through the encryption process we
25006
17:59:16,256 --> 17:59:17,256
come across around two different types
25007
17:59:18,060 --> 17:59:19,060
of text that I just pointed out first
25008
17:59:20,096 --> 17:59:21,096
there's plain text this is the
25009
17:59:22,080 --> 17:59:23,080
unencrypted data at this point anyone
25010
17:59:24,180 --> 17:59:25,180
can read what it says because there's no
25011
17:59:25,860 --> 17:59:26,860
code on it then there's ciphertext which
25012
17:59:28,380 --> 17:59:29,380
is the encrypted data the data that can
25013
17:59:30,840 --> 17:59:31,840
only be decrypted using a special key or
25014
17:59:33,776 --> 17:59:34,776
using that special algorithm
25015
17:59:35,880 --> 17:59:36,880
so in the world of encryption there are
25016
17:59:38,160 --> 17:59:39,160
normally two different types of keys or
25017
17:59:41,096 --> 17:59:42,096
algorithms in other words that come into
25018
17:59:42,900 --> 17:59:43,900
play first there are what are called
25019
17:59:44,756 --> 17:59:45,756
public Keys these are generally used in
25020
17:59:47,580 --> 17:59:48,580
some cases
25021
17:59:48,840 --> 17:59:49,840
to encrypt the data these keys are known
25022
17:59:52,500 --> 17:59:53,500
by both parties that's why they're
25023
17:59:55,200 --> 17:59:56,200
public they're put out on the web or
25024
17:59:58,020 --> 17:59:59,020
they're sent out by email or something
25025
17:59:59,580 --> 18:00:00,580
so everyone has it and these keys are
25026
18:00:02,096 --> 18:00:03,096
known by both parties so that in a data
25027
18:00:04,320 --> 18:00:05,320
transfer they can be used to encrypt the
25028
18:00:06,660 --> 18:00:07,660
data now in most cases the and receiving
25029
18:00:09,416 --> 18:00:10,416
the data receives the public key also so
25030
18:00:12,480 --> 18:00:13,480
if I'm sending you uh an encrypted sort
25031
18:00:15,660 --> 18:00:16,660
of message I'm going to send you the
25032
18:00:17,096 --> 18:00:18,096
public key along with my data now the
25033
18:00:20,340 --> 18:00:21,340
way that encryption and decryption will
25034
18:00:21,776 --> 18:00:22,776
work is the same way these public Keys
25035
18:00:23,936 --> 18:00:24,936
run plain text through the encryption
25036
18:00:25,980 --> 18:00:26,980
algorithm and they Place coding on it
25037
18:00:28,320 --> 18:00:29,320
now private keys on the other hand are
25038
18:00:30,776 --> 18:00:31,776
usually only used to decrypt the data so
25039
18:00:34,380 --> 18:00:35,380
I will send you my public key you will
25040
18:00:37,200 --> 18:00:38,200
encrypt a message send it to me and I
25041
18:00:39,900 --> 18:00:40,900
can only decrypt that using a private
25042
18:00:41,880 --> 18:00:42,880
key which only I have and so this is
25043
18:00:45,116 --> 18:00:46,116
basically how the whole system works now
25044
18:00:48,000 --> 18:00:49,000
there are different types of uh
25045
18:00:50,820 --> 18:00:51,820
encryption systems somewhere both sides
25046
18:00:52,860 --> 18:00:53,860
have to have public keys somewhere we
25047
18:00:54,416 --> 18:00:55,416
have a private key again I'm not going
25048
18:00:56,160 --> 18:00:57,160
to get too in depth with that right now
25049
18:00:57,720 --> 18:00:58,720
because this really gets into more of
25050
18:01:00,956 --> 18:01:01,956
security and Security Plus but the
25051
18:01:02,936 --> 18:01:03,936
important thing to realize is that the
25052
18:01:04,380 --> 18:01:05,380
public key
25053
18:01:05,636 --> 18:01:06,636
goes to both parties whereas the private
25054
18:01:08,040 --> 18:01:09,040
key which is only used usually to
25055
18:01:10,200 --> 18:01:11,200
decrypt the data is only held on to one
25056
18:01:12,540 --> 18:01:13,540
person so I could anyone can encrypt the
25057
18:01:15,116 --> 18:01:16,116
message but only someone with the
25058
18:01:16,560 --> 18:01:17,560
private key is going to be able to
25059
18:01:17,840 --> 18:01:18,840
decrypt the message
25060
18:01:20,400 --> 18:01:21,400
so if we take a look at how this works
25061
18:01:23,220 --> 18:01:24,220
um company a needs to send data to
25062
18:01:26,456 --> 18:01:27,456
Company B but it's really important
25063
18:01:28,136 --> 18:01:29,136
information that needs to be secure and
25064
18:01:29,756 --> 18:01:30,756
encrypted so Company B sends the public
25065
18:01:35,340 --> 18:01:36,340
key to company a
25066
18:01:38,096 --> 18:01:39,096
company be created this public key so
25067
18:01:40,500 --> 18:01:41,500
that the encryption and decryption would
25068
18:01:42,296 --> 18:01:43,296
work with each other now company a uses
25069
18:01:44,756 --> 18:01:45,756
this key to encrypt the data then sends
25070
18:01:46,860 --> 18:01:47,860
it to Company B and Company B uses the
25071
18:01:50,096 --> 18:01:51,096
private key that only they have
25072
18:01:52,980 --> 18:01:53,980
in order to decrypt the data now you can
25073
18:01:55,796 --> 18:01:56,796
only encrypt in this case with the
25074
18:01:59,276 --> 18:02:00,276
public key and you need the private key
25075
18:02:02,160 --> 18:02:03,160
in order to decrypt that's how this
25076
18:02:04,200 --> 18:02:05,200
works but the way that company a got it
25077
18:02:07,200 --> 18:02:08,200
is because Company B sent the public key
25078
18:02:10,256 --> 18:02:11,256
over to them
25079
18:02:12,000 --> 18:02:13,000
all right so just to recap we began by
25080
18:02:14,096 --> 18:02:15,096
defining And discussing cryptography
25081
18:02:15,916 --> 18:02:16,916
cryptography again is basically having a
25082
18:02:19,080 --> 18:02:20,080
code of some sort uh we use codes in all
25083
18:02:22,080 --> 18:02:23,080
sorts of ways we talked about the Navajo
25084
18:02:24,240 --> 18:02:25,240
Indians using codes during World War II
25085
18:02:26,276 --> 18:02:27,276
and we also talked about the Caesar
25086
18:02:28,380 --> 18:02:29,380
Cipher which basically just means adding
25087
18:02:30,540 --> 18:02:31,540
a certain number
25088
18:02:32,880 --> 18:02:33,880
two uh letters so for instance if I have
25089
18:02:35,936 --> 18:02:36,936
plus 2 as my Caesar Cipher and I want to
25090
18:02:38,820 --> 18:02:39,820
write the letter A instead I'm going to
25091
18:02:40,860 --> 18:02:41,860
write the letter c because it goes a b c
25092
18:02:44,820 --> 18:02:45,820
right there are two added so then if I
25093
18:02:49,320 --> 18:02:50,320
sent this C to someone they know oh I
25094
18:02:52,616 --> 18:02:53,616
can subtract two from it and that's my
25095
18:02:54,180 --> 18:02:55,180
Caesar Cipher now we also defined
25096
18:02:56,340 --> 18:02:57,340
encryption and encryption is actually
25097
18:02:58,680 --> 18:02:59,680
the process of doing all this we have
25098
18:03:00,956 --> 18:03:01,956
the code we have the cryptography and
25099
18:03:03,116 --> 18:03:04,116
then what we want to do is actually
25100
18:03:04,136 --> 18:03:05,136
encrypt the data using it now we talked
25101
18:03:06,480 --> 18:03:07,480
about two different things plain text
25102
18:03:07,860 --> 18:03:08,860
and ciphertext plain text is the data
25103
18:03:10,560 --> 18:03:11,560
before we apply the code to it
25104
18:03:12,136 --> 18:03:13,136
ciphertext is after we've applied it to
25105
18:03:15,296 --> 18:03:16,296
it so plain text anyone can read
25106
18:03:17,400 --> 18:03:18,400
ciphertext only those people with the
25107
18:03:19,436 --> 18:03:20,436
code breaker can read or the keys we
25108
18:03:22,080 --> 18:03:23,080
also talked about that in a public and
25109
18:03:23,636 --> 18:03:24,636
private key public keys are sent to
25110
18:03:27,000 --> 18:03:28,000
everyone so everyone has access to them
25111
18:03:29,936 --> 18:03:30,936
private keys are only held by one party
25112
18:03:33,000 --> 18:03:34,000
they are private now generally speaking
25113
18:03:36,360 --> 18:03:37,360
public keys are used to encrypt
25114
18:03:40,560 --> 18:03:41,560
whereas private keys are used to decrypt
25115
18:03:42,956 --> 18:03:43,956
so anyone can make uh a message that is
25116
18:03:46,860 --> 18:03:47,860
in ciphertext but only the people with
25117
18:03:48,596 --> 18:03:49,596
the private keys can actually decipher
25118
18:03:50,636 --> 18:03:51,636
it
25119
18:03:51,360 --> 18:03:52,360
and then we talked about some like
25120
18:03:52,980 --> 18:03:53,980
examples of using this for instance not
25121
18:03:55,320 --> 18:03:56,320
only the Caesar and the Navajo but we
25122
18:03:57,240 --> 18:03:58,240
also talked about wanting to use it for
25123
18:03:58,860 --> 18:03:59,860
Social Security numbers passwords are a
25124
18:04:01,436 --> 18:04:02,436
big one
25125
18:04:02,636 --> 18:04:03,636
and of course today's market with all
25126
18:04:04,916 --> 18:04:05,916
the finances going on bank and credit
25127
18:04:07,320 --> 18:04:08,320
card information
25128
18:04:14,200 --> 18:04:15,200
[Music]
25129
18:04:34,220 --> 18:04:35,220
network security IDs IPS implementation
25130
18:04:40,080 --> 18:04:41,080
in the previous lesson we talked about
25131
18:04:41,880 --> 18:04:42,880
different aspects of network security
25132
18:04:43,680 --> 18:04:44,680
now because this topic is so
25133
18:04:46,136 --> 18:04:47,136
encompassing we're going to continue on
25134
18:04:48,060 --> 18:04:49,060
with this network security in this
25135
18:04:50,520 --> 18:04:51,520
lesson where we're going to focus
25136
18:04:51,840 --> 18:04:52,840
specifically on two types of security
25137
18:04:54,180 --> 18:04:55,180
one is IP security which we'll talk
25138
18:04:56,580 --> 18:04:57,580
about in the next module and in this
25139
18:04:59,096 --> 18:05:00,096
module we're going to talk about
25140
18:04:59,880 --> 18:05:00,880
intrusion detection prevention systems
25141
18:05:02,276 --> 18:05:03,276
otherwise known as IDs and IPS these are
25142
18:05:06,240 --> 18:05:07,240
pretty important and come up a bit on
25143
18:05:07,680 --> 18:05:08,680
the network plus exam which is why I
25144
18:05:09,180 --> 18:05:10,180
want to commit an entire module to them
25145
18:05:11,096 --> 18:05:12,096
so we're going to begin by talking about
25146
18:05:13,680 --> 18:05:14,680
an IDs or intrusion
25147
18:05:18,616 --> 18:05:19,616
detection system
25148
18:05:22,256 --> 18:05:23,256
notice the D there and we're going to
25149
18:05:24,720 --> 18:05:25,720
talk about the two different types of
25150
18:05:26,276 --> 18:05:27,276
IDs that exist one is behavior based and
25151
18:05:30,116 --> 18:05:31,116
one is signature based we'll discuss
25152
18:05:32,220 --> 18:05:33,220
what this means in a bit we're also
25153
18:05:34,380 --> 18:05:35,380
going to Define and discuss ips's the
25154
18:05:37,020 --> 18:05:38,020
difference between an IPS and an IDs is
25155
18:05:39,180 --> 18:05:40,180
where an IDs is an intrusion detection
25156
18:05:41,340 --> 18:05:42,340
system and IPS is an intrusion
25157
18:05:44,956 --> 18:05:45,956
prevention system notice the difference
25158
18:05:48,116 --> 18:05:49,116
between the D and the P one simply
25159
18:05:50,456 --> 18:05:51,456
notifies you the other will actually
25160
18:05:52,200 --> 18:05:53,200
prevent we're then going to discuss the
25161
18:05:54,900 --> 18:05:55,900
importance of having an IDs IPS and in
25162
18:05:57,776 --> 18:05:58,776
some cases we will have devices that do
25163
18:06:00,000 --> 18:06:01,000
both
25164
18:06:01,256 --> 18:06:02,256
and we're then going to discuss very
25165
18:06:03,296 --> 18:06:04,296
briefly implementation now of course
25166
18:06:05,820 --> 18:06:06,820
just like anything we're going to look
25167
18:06:07,560 --> 18:06:08,560
at this from a mile high view so this
25168
18:06:09,900 --> 18:06:10,900
isn't the in-depth the detailed version
25169
18:06:11,580 --> 18:06:12,580
this is the broad overview now an
25170
18:06:14,880 --> 18:06:15,880
intrusion detection system is software
25171
18:06:17,220 --> 18:06:18,220
or network device that's used to detect
25172
18:06:20,700 --> 18:06:21,700
again remember that word d detect
25173
18:06:23,000 --> 18:06:24,000
attacks or intrusions that are made on
25174
18:06:25,500 --> 18:06:26,500
the network the attacks that it detects
25175
18:06:27,900 --> 18:06:28,900
are then reported to either the
25176
18:06:29,700 --> 18:06:30,700
administrator or to a threat log sort of
25177
18:06:33,360 --> 18:06:34,360
like the Event Viewer if it logs the
25178
18:06:36,060 --> 18:06:37,060
information first it then alerts the
25179
18:06:38,456 --> 18:06:39,456
administrator so the administrator can
25180
18:06:41,096 --> 18:06:42,096
look into the issue now while IDs are up
25181
18:06:44,276 --> 18:06:45,276
to date and make alerts as soon as an
25182
18:06:46,256 --> 18:06:47,256
attack occurs they are still referred to
25183
18:06:48,360 --> 18:06:49,360
as passive the reason they are called a
25184
18:06:51,596 --> 18:06:52,596
passive security system is because they
25185
18:06:53,276 --> 18:06:54,276
don't do anything to actually prevent
25186
18:06:55,680 --> 18:06:56,680
the intrusion from stopping all they do
25187
18:06:58,860 --> 18:06:59,860
is they passively notice that it's
25188
18:07:02,160 --> 18:07:03,160
occurring this is because again they
25189
18:07:04,380 --> 18:07:05,380
merely a detect the attack they don't do
25190
18:07:06,540 --> 18:07:07,540
anything to prevent or combat it now
25191
18:07:08,580 --> 18:07:09,580
there are a few different types of
25192
18:07:10,020 --> 18:07:11,020
intrusion detection systems but I want
25193
18:07:12,000 --> 18:07:13,000
to focus specifically on two different
25194
18:07:13,616 --> 18:07:14,616
types the first is called a
25195
18:07:15,980 --> 18:07:16,980
behavior-based system this makes alerts
25196
18:07:19,020 --> 18:07:20,020
and reports of attacks based on the
25197
18:07:21,680 --> 18:07:22,680
behavior that they deem to be suspicious
25198
18:07:25,020 --> 18:07:26,020
or out of the ordinary these unusual
25199
18:07:27,480 --> 18:07:28,480
behaviors can include large amounts of
25200
18:07:30,660 --> 18:07:31,660
traffic policies being violated
25201
18:07:35,040 --> 18:07:36,040
um and even people attempting to access
25202
18:07:37,916 --> 18:07:38,916
things that they're not supposed to
25203
18:07:42,296 --> 18:07:43,296
now a signature-based system detects the
25204
18:07:45,180 --> 18:07:46,180
Rest by reading their attack signatures
25205
18:07:48,000 --> 18:07:49,000
just like a virus scan program has a
25206
18:07:51,956 --> 18:07:52,956
signature remember those data files we
25207
18:07:54,720 --> 18:07:55,720
talked about that tells it what to look
25208
18:07:56,456 --> 18:07:57,456
for in a virus intrusion or attack
25209
18:07:59,756 --> 18:08:00,756
systems have a signature and a signature
25210
18:08:04,020 --> 18:08:05,020
file that they can look at that lines up
25211
18:08:07,200 --> 18:08:08,200
with the signature of an attack or an
25212
18:08:09,840 --> 18:08:10,840
intrusion
25213
18:08:10,916 --> 18:08:11,916
so signature based systems scan the
25214
18:08:13,560 --> 18:08:14,560
signatures of known attacks and when it
25215
18:08:15,776 --> 18:08:16,776
detects one of these signatures
25216
18:08:17,220 --> 18:08:18,220
attacking its system it makes an alert
25217
18:08:19,560 --> 18:08:20,560
to the administrator or reports it to a
25218
18:08:21,360 --> 18:08:22,360
log so again the signature is based on
25219
18:08:24,180 --> 18:08:25,180
more or less a history whereas behavior
25220
18:08:26,936 --> 18:08:27,936
is based on what we see
25221
18:08:28,860 --> 18:08:29,860
they're looking at two different types
25222
18:08:30,540 --> 18:08:31,540
of attacks and there are the pluses and
25223
18:08:32,040 --> 18:08:33,040
benefits pluses and minuses rather of
25224
18:08:34,200 --> 18:08:35,200
both but you can see Behavior again is
25225
18:08:36,660 --> 18:08:37,660
looking at a more all-encompassing
25226
18:08:38,096 --> 18:08:39,096
General sort of view where a signature
25227
18:08:40,020 --> 18:08:41,020
based is looking at previous histories
25228
18:08:42,180 --> 18:08:43,180
of attacks and aligning the upcoming or
25229
18:08:44,936 --> 18:08:45,936
current attack with that
25230
18:08:46,916 --> 18:08:47,916
so here's how an IDs Works an attacker
25231
18:08:50,936 --> 18:08:51,936
shown on the left sends an attack
25232
18:08:52,796 --> 18:08:53,796
through the internet in order to access
25233
18:08:54,840 --> 18:08:55,840
the network of the local app
25234
18:08:57,180 --> 18:08:58,180
area network the attacks go through the
25235
18:08:59,820 --> 18:09:00,820
internet towards the network now in
25236
18:09:02,160 --> 18:09:03,160
between the internet and the firewall is
25237
18:09:04,320 --> 18:09:05,320
this IDs and what it does is it detects
25238
18:09:07,916 --> 18:09:08,916
the attacks being made and sends an
25239
18:09:09,720 --> 18:09:10,720
alert to the administrator
25240
18:09:12,416 --> 18:09:13,416
though it doesn't do anything to block
25241
18:09:14,636 --> 18:09:15,636
the attack this is okay because the
25242
18:09:16,560 --> 18:09:17,560
firewall is still set up to handle the
25243
18:09:18,596 --> 18:09:19,596
attack so the attacker comes in isn't
25244
18:09:21,720 --> 18:09:22,720
able to access the information
25245
18:09:23,756 --> 18:09:24,756
but the administrator is still alerted
25246
18:09:26,276 --> 18:09:27,276
that there is an issue going on and in
25247
18:09:28,680 --> 18:09:29,680
case the attacker begins to double their
25248
18:09:30,720 --> 18:09:31,720
efforts the administrator can sort of
25249
18:09:33,116 --> 18:09:34,116
get on it and make sure that nothing is
25250
18:09:35,040 --> 18:09:36,040
going to get through now similar to the
25251
18:09:37,380 --> 18:09:38,380
intrusion detection system and intrusion
25252
18:09:39,596 --> 18:09:40,596
prevention system also detects attacks
25253
18:09:41,936 --> 18:09:42,936
that are targeting the network however
25254
18:09:44,000 --> 18:09:45,000
intrusion prevention systems not only
25255
18:09:46,616 --> 18:09:47,616
detect the attack they also prevent it
25256
18:09:50,160 --> 18:09:51,160
from happening and causing more issues
25257
18:09:52,500 --> 18:09:53,500
on the network these are considered more
25258
18:09:54,900 --> 18:09:55,900
reactive
25259
18:09:56,900 --> 18:09:57,900
or proactive
25260
18:10:00,060 --> 18:10:01,060
software or Hardware because ips's do a
25261
18:10:04,020 --> 18:10:05,020
lot more than ids's do they're reactive
25262
18:10:06,596 --> 18:10:07,596
in the sense that if an attack is
25263
18:10:07,916 --> 18:10:08,916
attempted they're going to block it from
25264
18:10:09,296 --> 18:10:10,296
entering the network just like uh a
25265
18:10:11,936 --> 18:10:12,936
breaker box is going to
25266
18:10:14,456 --> 18:10:15,456
sort of kill the circuit by breaking by
25267
18:10:18,180 --> 18:10:19,180
switching the breaker before the
25268
18:10:19,916 --> 18:10:20,916
electricity can do any damage to the
25269
18:10:21,776 --> 18:10:22,776
wall a ips's might even kill the
25270
18:10:24,776 --> 18:10:25,776
connection out to the internet to stop
25271
18:10:26,636 --> 18:10:27,636
anything from happening they're also
25272
18:10:28,740 --> 18:10:29,740
proactive because certain ips's are
25273
18:10:30,596 --> 18:10:31,596
going to seek out attacks and stop them
25274
18:10:32,580 --> 18:10:33,580
before they even make an attempt on the
25275
18:10:34,560 --> 18:10:35,560
network uh for instance scanning for
25276
18:10:37,740 --> 18:10:38,740
ports in this way an intrusion
25277
18:10:39,596 --> 18:10:40,596
prevention system is more expensive than
25278
18:10:42,000 --> 18:10:43,000
an IDs but this is because it does a lot
25279
18:10:44,040 --> 18:10:45,040
more to provide safety for the network
25280
18:10:46,080 --> 18:10:47,080
rather than leaving the job in the hands
25281
18:10:48,116 --> 18:10:49,116
of administrator who perhaps isn't even
25282
18:10:50,040 --> 18:10:51,040
on site at three in the morning the IPS
25283
18:10:52,560 --> 18:10:53,560
is going to handle the attack and
25284
18:10:54,776 --> 18:10:55,776
prevent the attacker from connecting to
25285
18:10:56,636 --> 18:10:57,636
the network and IDs only alerts the
25286
18:10:59,276 --> 18:11:00,276
administrator and does nothing about it
25287
18:11:01,136 --> 18:11:02,136
for this reason ips's are more expensive
25288
18:11:03,840 --> 18:11:04,840
neither system is exactly cheap and
25289
18:11:06,596 --> 18:11:07,596
ips's can sell for maybe even fifty
25290
18:11:09,956 --> 18:11:10,956
thousand dollars depending on how
25291
18:11:12,200 --> 18:11:13,200
versatile it is so here's what an
25292
18:11:15,296 --> 18:11:16,296
intrusion prevention system looks like
25293
18:11:17,180 --> 18:11:18,180
as you can see it's pretty similar to
25294
18:11:19,616 --> 18:11:20,616
the IDS but with one major difference
25295
18:11:21,416 --> 18:11:22,416
it's that
25296
18:11:23,340 --> 18:11:24,340
the intrusion prevention system is
25297
18:11:25,380 --> 18:11:26,380
actually going to stop the attack from
25298
18:11:29,096 --> 18:11:30,096
taking place it still sends an alert out
25299
18:11:32,220 --> 18:11:33,220
to the administrator so the
25300
18:11:33,360 --> 18:11:34,360
administrator can take care of this but
25301
18:11:35,096 --> 18:11:36,096
it actually stops the attack in its
25302
18:11:36,840 --> 18:11:37,840
place and makes sure that nothing is
25303
18:11:38,756 --> 18:11:39,756
going to occur whereas the IDS is going
25304
18:11:41,820 --> 18:11:42,820
to rely mostly on the firewall to add
25305
18:11:45,180 --> 18:11:46,180
Prevention Services again this is a lot
25306
18:11:47,400 --> 18:11:48,400
more expensive but if my network has a
25307
18:11:49,796 --> 18:11:50,796
lot of stuff going on in it I probably
25308
18:11:51,360 --> 18:11:52,360
want to spend the money in order to
25309
18:11:53,700 --> 18:11:54,700
provide more security for my network
25310
18:11:55,860 --> 18:11:56,860
now there are a few reasons why
25311
18:11:57,660 --> 18:11:58,660
implementing an IDs or IPS is beneficial
25312
18:12:00,180 --> 18:12:01,180
first they're going to help provide
25313
18:12:01,740 --> 18:12:02,740
additional security to a network the
25314
18:12:03,660 --> 18:12:04,660
more security we have the more one of
25315
18:12:06,540 --> 18:12:07,540
the important words we see a lot in
25316
18:12:08,400 --> 18:12:09,400
computers the more redundancy we have
25317
18:12:11,700 --> 18:12:12,700
the better adding layers of security and
25318
18:12:14,636 --> 18:12:15,636
IPS and a firewall for instance is like
25319
18:12:17,100 --> 18:12:18,100
wearing multiple layers of clothing in
25320
18:12:18,960 --> 18:12:19,960
the cold the more layers the more
25321
18:12:20,696 --> 18:12:21,696
protected you are now firewalls and
25322
18:12:23,100 --> 18:12:24,100
Antivirus systems are great but they are
25323
18:12:26,460 --> 18:12:27,460
flawed in that they're not able to
25324
18:12:28,564 --> 18:12:29,564
handle every type of threat ids's and
25325
18:12:31,376 --> 18:12:32,376
ips's can detect and take care of
25326
18:12:33,720 --> 18:12:34,720
threats that might not otherwise be
25327
18:12:35,936 --> 18:12:36,936
found by the firewall or by the virus
25328
18:12:38,400 --> 18:12:39,400
scan program so there's really not a
25329
18:12:40,256 --> 18:12:41,256
single system or program that can
25330
18:12:41,460 --> 18:12:42,460
protect against all attacks but the
25331
18:12:43,564 --> 18:12:44,564
protection features of multiple
25332
18:12:45,000 --> 18:12:46,000
different types of systems can actually
25333
18:12:47,040 --> 18:12:48,040
add up to very thick layers of
25334
18:12:49,376 --> 18:12:50,376
protection for an attack finally the IDS
25335
18:12:52,140 --> 18:12:53,140
IPS keeps a record of all the attacks
25336
18:12:54,600 --> 18:12:55,600
they detect this comes in handy because
25337
18:12:56,516 --> 18:12:57,516
it lets the administrator see where on
25338
18:12:58,376 --> 18:12:59,376
the network they're being targeted most
25339
18:12:59,820 --> 18:13:00,820
and then allows the administrator to
25340
18:13:01,564 --> 18:13:02,564
make changes add protection of the
25341
18:13:03,420 --> 18:13:04,420
places that are attacked most often and
25342
18:13:05,696 --> 18:13:06,696
most importantly create new policies
25343
18:13:07,256 --> 18:13:08,256
that are going to prevent security
25344
18:13:08,460 --> 18:13:09,460
breaches in the future now while I'm not
25345
18:13:10,920 --> 18:13:11,920
going to get into the technical aspects
25346
18:13:12,540 --> 18:13:13,540
of implementing these systems as I said
25347
18:13:14,280 --> 18:13:15,280
I want to talk about what we need to
25348
18:13:16,140 --> 18:13:17,140
consider while we're considering putting
25349
18:13:18,960 --> 18:13:19,960
in an IPS or IDs first we need to figure
25350
18:13:22,080 --> 18:13:23,080
out the ideal placement of the IDS IPS
25351
18:13:24,720 --> 18:13:25,720
on the network this means figure figure
25352
18:13:26,696 --> 18:13:27,696
out where the sensors are that are going
25353
18:13:28,320 --> 18:13:29,320
to provide the most coverage an IDs IPS
25354
18:13:30,836 --> 18:13:31,836
needs to be set up where choke points
25355
18:13:33,360 --> 18:13:34,360
are available a choke point is a
25356
18:13:37,320 --> 18:13:38,320
strategy that involves narrowing down
25357
18:13:39,836 --> 18:13:40,836
the physical space that an attacker is
25358
18:13:41,936 --> 18:13:42,936
able to utilize and The Logical space as
25359
18:13:44,460 --> 18:13:45,460
well this way the defenses must easier
25360
18:13:47,100 --> 18:13:48,100
so we're really limiting the area
25361
18:13:50,756 --> 18:13:51,756
of our vulnerability much like
25362
18:13:53,516 --> 18:13:54,516
Achilles heel using choke points is
25363
18:13:56,100 --> 18:13:57,100
actually something that's been in
25364
18:13:57,180 --> 18:13:58,180
militaries throughout history notable is
25365
18:13:59,876 --> 18:14:00,876
like the Spartan Army of 300 men which
25366
18:14:02,280 --> 18:14:03,280
it used against the Persians when they
25367
18:14:03,900 --> 18:14:04,900
were greatly outnumbered by forcing all
25368
18:14:06,064 --> 18:14:07,064
of the attackers into a smaller path
25369
18:14:10,680 --> 18:14:11,680
so if we had a mountain right
25370
18:14:13,016 --> 18:14:14,016
and we make sure that everyone's coming
25371
18:14:15,244 --> 18:14:16,244
up through this path then we can really
25372
18:14:17,696 --> 18:14:18,696
attack them a lot easier from Atop The
25373
18:14:19,680 --> 18:14:20,680
Mountain rather than having them come
25374
18:14:21,116 --> 18:14:22,116
all around the mountain
25375
18:14:23,876 --> 18:14:24,876
next the administrator needs to
25376
18:14:26,280 --> 18:14:27,280
fine-tune the alerts the IDS and IPS
25377
18:14:28,436 --> 18:14:29,436
outputs so that they are more useful if
25378
18:14:32,156 --> 18:14:33,156
the alert merely says an attack is
25379
18:14:34,016 --> 18:14:35,016
taking place this doesn't give the
25380
18:14:35,336 --> 18:14:36,336
administrator anything to go off of the
25381
18:14:37,376 --> 18:14:38,376
alerts really need to be detailed and
25382
18:14:39,116 --> 18:14:40,116
tailored to exactly what the
25383
18:14:40,616 --> 18:14:41,616
administrator needs to know this is
25384
18:14:42,476 --> 18:14:43,476
something that has to be set up and
25385
18:14:43,680 --> 18:14:44,680
tested by the administrator once the
25386
18:14:45,360 --> 18:14:46,360
alerts have been configured and once
25387
18:14:47,156 --> 18:14:48,156
attacks start taking place next the
25388
18:14:49,500 --> 18:14:50,500
monitoring of the alerts needs to be
25389
18:14:50,876 --> 18:14:51,876
handled what use are the alerts if no
25390
18:14:53,220 --> 18:14:54,220
one's seeing them the administrator
25391
18:14:55,016 --> 18:14:56,016
can't always be on the network
25392
18:14:56,336 --> 18:14:57,336
constantly looking out for the alerts
25393
18:14:58,140 --> 18:14:59,140
they're sent so it's their job however
25394
18:15:00,540 --> 18:15:01,540
to set up a way for the alerts to be
25395
18:15:02,580 --> 18:15:03,580
monitored this might involve hiring an
25396
18:15:05,820 --> 18:15:06,820
employee to monitor it constantly
25397
18:15:07,320 --> 18:15:08,320
something we used to call beeper Duty
25398
18:15:09,720 --> 18:15:10,720
where someone was always on 24-hour call
25399
18:15:13,220 --> 18:15:14,220
or configuring a way for the
25400
18:15:15,360 --> 18:15:16,360
administrator to get alerts remotely say
25401
18:15:17,696 --> 18:15:18,696
a text message
25402
18:15:19,376 --> 18:15:20,376
finally procedures need to be put in
25403
18:15:21,360 --> 18:15:22,360
place for what's going to happen in the
25404
18:15:23,100 --> 18:15:24,100
event of an attack the question what's
25405
18:15:25,376 --> 18:15:26,376
our plan of action needs to be asked
25406
18:15:28,920 --> 18:15:29,920
just in case an attack goes on so we
25407
18:15:31,616 --> 18:15:32,616
know what is going to uh what programs
25408
18:15:34,256 --> 18:15:35,256
are we going to deploy what Hardware do
25409
18:15:37,080 --> 18:15:38,080
we shut off our connection to the
25410
18:15:38,756 --> 18:15:39,756
network Etc if an attack happens it's
25411
18:15:41,100 --> 18:15:42,100
really up to the administrator to lead
25412
18:15:42,540 --> 18:15:43,540
the defense and the strategy around that
25413
18:15:44,400 --> 18:15:45,400
defense
25414
18:15:46,320 --> 18:15:47,320
so just to recap we first talked about
25415
18:15:49,080 --> 18:15:50,080
an intrusion detection system and
25416
18:15:51,900 --> 18:15:52,900
remember that D is really important
25417
18:15:53,936 --> 18:15:54,936
which is a passive system because it
25418
18:15:57,244 --> 18:15:58,244
simply detects an intrusion as it's
25419
18:15:59,756 --> 18:16:00,756
occurring and notifies
25420
18:16:02,516 --> 18:16:03,516
an administrator
25421
18:16:06,296 --> 18:16:07,296
we also talked about the two different
25422
18:16:07,920 --> 18:16:08,920
types of IDs as there are behavior-based
25423
18:16:10,976 --> 18:16:11,976
and signature based behavior-based looks
25424
18:16:14,220 --> 18:16:15,220
at behaviors
25425
18:16:15,836 --> 18:16:16,836
such as high traffic
25426
18:16:19,436 --> 18:16:20,436
people accessing things they shouldn't
25427
18:16:22,016 --> 18:16:23,016
be or areas being accessed that aren't
25428
18:16:24,180 --> 18:16:25,180
normally accessed whereas signature
25429
18:16:26,156 --> 18:16:27,156
based looks at historical data in the
25430
18:16:30,000 --> 18:16:31,000
form of signature files
25431
18:16:31,976 --> 18:16:32,976
and tries to match these up
25432
18:16:35,820 --> 18:16:36,820
with known attacks
25433
18:16:38,876 --> 18:16:39,876
of course if the attack isn't known then
25434
18:16:41,460 --> 18:16:42,460
it's not going to be available in the
25435
18:16:42,960 --> 18:16:43,960
signature and so this is where a
25436
18:16:44,580 --> 18:16:45,580
behavior would come in play
25437
18:16:46,256 --> 18:16:47,256
we also talked about ips's or intrusion
25438
18:16:49,876 --> 18:16:50,876
prevention systems
25439
18:16:52,140 --> 18:16:53,140
which are proactive because they might
25440
18:16:56,100 --> 18:16:57,100
search for vulnerabilities
25441
18:16:58,616 --> 18:16:59,616
in the system such as looking for open
25442
18:17:00,900 --> 18:17:01,900
ports and reactive
25443
18:17:04,860 --> 18:17:05,860
because they actually stop an attack in
25444
18:17:08,580 --> 18:17:09,580
its tracks or at least they attempt to
25445
18:17:11,420 --> 18:17:12,420
now the importance of IDs and ips's is
25446
18:17:15,244 --> 18:17:16,244
added or extra security
25447
18:17:19,376 --> 18:17:20,376
just like as we mentioned having
25448
18:17:21,476 --> 18:17:22,476
multiple layers if you're going out and
25449
18:17:23,280 --> 18:17:24,280
it's cold outside
25450
18:17:24,836 --> 18:17:25,836
it's also important because we want to
25451
18:17:27,244 --> 18:17:28,244
know how to alter
25452
18:17:30,960 --> 18:17:31,960
our security policies over time to make
25453
18:17:33,600 --> 18:17:34,600
them more secure
25454
18:17:37,080 --> 18:17:38,080
and when we talked about implementation
25455
18:17:38,876 --> 18:17:39,876
from a very Broad View some of the
25456
18:17:40,920 --> 18:17:41,920
things we talked about is placement
25457
18:17:43,564 --> 18:17:44,564
we want them remember in areas called
25458
18:17:46,796 --> 18:17:47,796
choke points
25459
18:17:49,696 --> 18:17:50,696
meaning we want to limit the amount of
25460
18:17:52,196 --> 18:17:53,196
areas that are outside network has
25461
18:17:55,564 --> 18:17:56,564
access to to the inside we also talked
25462
18:17:58,616 --> 18:17:59,616
about monitoring
25463
18:18:00,900 --> 18:18:01,900
and how we get notifications which in
25464
18:18:04,196 --> 18:18:05,196
some cases needs to be through text
25465
18:18:07,256 --> 18:18:08,256
messaging or email
25466
18:18:10,256 --> 18:18:11,256
or anything else finally we needed to
25467
18:18:13,436 --> 18:18:14,436
talk about what we do a plan of action
25468
18:18:18,180 --> 18:18:19,180
in case we actually have an attack
25469
18:18:20,336 --> 18:18:21,336
occurring
25470
18:18:25,330 --> 18:18:26,330
[Music]
25471
18:18:34,040 --> 18:18:35,040
thank you
25472
18:18:45,180 --> 18:18:46,180
network security
25473
18:18:46,936 --> 18:18:47,936
ipsec and ipsec policies
25474
18:18:51,244 --> 18:18:52,244
having discussed intrusion detection and
25475
18:18:53,580 --> 18:18:54,580
prevention systems which are mostly
25476
18:18:55,436 --> 18:18:56,436
having to do with keeping attacks and
25477
18:18:58,140 --> 18:18:59,140
malicious software off our Network I
25478
18:19:00,244 --> 18:19:01,244
want to talk about something called
25479
18:19:01,680 --> 18:19:02,680
ipsec or IP security which is a sort of
25480
18:19:07,436 --> 18:19:08,436
group of protocols and policies that are
25481
18:19:10,976 --> 18:19:11,976
used to keep the data that we have
25482
18:19:13,256 --> 18:19:14,256
secure on a network whenever we talk
25483
18:19:15,836 --> 18:19:16,836
about security there's something called
25484
18:19:17,756 --> 18:19:18,756
CIA the CIA Triad that we need to keep
25485
18:19:20,040 --> 18:19:21,040
in mind C stands for
25486
18:19:23,540 --> 18:19:24,540
confidentiality meaning only the people
25487
18:19:26,336 --> 18:19:27,336
we want to see something actually see it
25488
18:19:29,040 --> 18:19:30,040
the I stands for integrity meaning what
25489
18:19:33,540 --> 18:19:34,540
we send is what the other party receives
25490
18:19:35,696 --> 18:19:36,696
it hasn't been tampered with and finally
25491
18:19:38,220 --> 18:19:39,220
we have to balance all of this against
25492
18:19:40,196 --> 18:19:41,196
availability it doesn't matter if
25493
18:19:42,600 --> 18:19:43,600
something is super secure if no one can
25494
18:19:44,820 --> 18:19:45,820
access it so broadening out into this
25495
18:19:48,244 --> 18:19:49,244
that's where ipsec comes into play so
25496
18:19:51,000 --> 18:19:52,000
we're going to talk about ipsec defining
25497
18:19:54,244 --> 18:19:55,244
And discussing what it is and then talk
25498
18:19:56,156 --> 18:19:57,156
about two protocols that we focus on
25499
18:19:58,796 --> 18:19:59,796
with ipsec ah and ESP
25500
18:20:02,280 --> 18:20:03,280
we're also going to discuss three
25501
18:20:04,256 --> 18:20:05,256
different services that ipsec uses or
25502
18:20:06,600 --> 18:20:07,600
serves one is data verification
25503
18:20:10,196 --> 18:20:11,196
protection from data tampering again
25504
18:20:12,540 --> 18:20:13,540
getting into that integrity
25505
18:20:15,180 --> 18:20:16,180
and private transactions going along
25506
18:20:18,360 --> 18:20:19,360
with that confidentiality all of this
25507
18:20:21,244 --> 18:20:22,244
supports availability and the reason we
25508
18:20:23,820 --> 18:20:24,820
have ipsec is to make sure that in our
25509
18:20:26,400 --> 18:20:27,400
security we have available data finally
25510
18:20:30,476 --> 18:20:31,476
I want to talk about some of the
25511
18:20:31,860 --> 18:20:32,860
policies the ways that we use ipsec
25512
18:20:35,460 --> 18:20:36,460
so as I mentioned a good amount of the
25513
18:20:37,500 --> 18:20:38,500
security measures that we use on a
25514
18:20:39,116 --> 18:20:40,116
network are used to prevent attacks and
25515
18:20:41,156 --> 18:20:42,156
shield the network from viruses and
25516
18:20:43,196 --> 18:20:44,196
other malicious software but not all
25517
18:20:45,476 --> 18:20:46,476
security measures are used for the
25518
18:20:47,400 --> 18:20:48,400
preventions of this malicious stuff some
25519
18:20:50,696 --> 18:20:51,696
are intended to keep data and
25520
18:20:52,256 --> 18:20:53,256
Communications secure within a network
25521
18:20:54,116 --> 18:20:55,116
while preventing attacks is certainly a
25522
18:20:56,280 --> 18:20:57,280
part of this there are some security
25523
18:20:57,960 --> 18:20:58,960
measures that exist to establish secure
25524
18:21:01,016 --> 18:21:02,016
and safe communication paths between two
25525
18:21:03,900 --> 18:21:04,900
parties this is what IP security or
25526
18:21:06,836 --> 18:21:07,836
ipsec protocols do
25527
18:21:08,876 --> 18:21:09,876
they're used to provide a secure channel
25528
18:21:11,460 --> 18:21:12,460
of communication between two systems or
25529
18:21:14,516 --> 18:21:15,516
more systems these systems can be within
25530
18:21:17,040 --> 18:21:18,040
a local network within a wide area
25531
18:21:18,780 --> 18:21:19,780
network perhaps even over a virtual
25532
18:21:20,696 --> 18:21:21,696
private Network now some people might
25533
18:21:23,280 --> 18:21:24,280
think that data traveling within a local
25534
18:21:25,320 --> 18:21:26,320
network is secure but this is only
25535
18:21:27,476 --> 18:21:28,476
sometimes true imagine that someone has
25536
18:21:30,656 --> 18:21:31,656
hacked into our Network and we're
25537
18:21:32,040 --> 18:21:33,040
sending data across it well now we want
25538
18:21:34,500 --> 18:21:35,500
to make sure that the data itself is
25539
18:21:35,936 --> 18:21:36,936
secure so while the entire network might
25540
18:21:38,400 --> 18:21:39,400
be protected by firewalls antivirus IDs
25541
18:21:41,400 --> 18:21:42,400
IPS there might be nothing protecting
25542
18:21:43,976 --> 18:21:44,976
the actual connection between the two
25543
18:21:45,600 --> 18:21:46,600
users generally the data that gets sent
25544
18:21:48,720 --> 18:21:49,720
across the network is not really heavily
25545
18:21:51,600 --> 18:21:52,600
protected or didn't used to be so people
25546
18:21:53,696 --> 18:21:54,696
tend to think that just because their
25547
18:21:55,140 --> 18:21:56,140
network has a shield around it
25548
18:21:56,756 --> 18:21:57,756
everything inside it is safe as well but
25549
18:21:59,220 --> 18:22:00,220
this isn't the case it's important to
25550
18:22:01,376 --> 18:22:02,376
have ipsec protocols in place to secure
25551
18:22:04,500 --> 18:22:05,500
the data sent and the connections made
25552
18:22:06,420 --> 18:22:07,420
over a network both local and wide area
25553
18:22:09,780 --> 18:22:10,780
now there are two main protocols that
25554
18:22:12,000 --> 18:22:13,000
are categorized in ipsec they are ah or
25555
18:22:16,320 --> 18:22:17,320
authentication header and ESP the
25556
18:22:19,564 --> 18:22:20,564
encapsulating security payload let's
25557
18:22:22,376 --> 18:22:23,376
talk a little bit more about what these
25558
18:22:23,936 --> 18:22:24,936
are
25559
18:22:24,836 --> 18:22:25,836
as the name States ah or authentication
25560
18:22:28,564 --> 18:22:29,564
header is used to authenticate
25561
18:22:31,460 --> 18:22:32,460
connections made over a network it does
25562
18:22:34,796 --> 18:22:35,796
this by checking the IP address
25563
18:22:39,244 --> 18:22:40,244
of the users that are trying to
25564
18:22:40,920 --> 18:22:41,920
communicate and make sure that they're
25565
18:22:42,420 --> 18:22:43,420
trusted it also checks the Integrity of
25566
18:22:46,744 --> 18:22:47,744
the data packets that are being sent in
25567
18:22:48,900 --> 18:22:49,900
other words is this the data that we
25568
18:22:50,936 --> 18:22:51,936
actually intended and was it received
25569
18:22:52,744 --> 18:22:53,744
properly
25570
18:22:54,000 --> 18:22:55,000
the other one encapsulating security
25571
18:22:56,336 --> 18:22:57,336
payload or ESP is used for encryption
25572
18:22:59,876 --> 18:23:00,876
Services which I think we've talked
25573
18:23:01,680 --> 18:23:02,680
about it encrypts data that's being sent
25574
18:23:03,900 --> 18:23:04,900
over a network using ah to authenticate
25575
18:23:07,564 --> 18:23:08,564
the users ESP will only give the keys to
25576
18:23:10,920 --> 18:23:11,920
the users that have been authenticated
25577
18:23:13,220 --> 18:23:14,220
so I make sure to authenticate using ah
25578
18:23:18,540 --> 18:23:19,540
that this is the user I want to give
25579
18:23:20,280 --> 18:23:21,280
something to and then the ESP
25580
18:23:24,180 --> 18:23:25,180
does the encryption
25581
18:23:26,476 --> 18:23:27,476
for the people who have been
25582
18:23:28,680 --> 18:23:29,680
authenticated providing Keys only to the
25583
18:23:32,640 --> 18:23:33,640
people who meet the first condition now
25584
18:23:35,156 --> 18:23:36,156
if this seems like a broad overview of
25585
18:23:36,836 --> 18:23:37,836
these two it is we're not going to see
25586
18:23:39,000 --> 18:23:40,000
this a whole lot on the network plus
25587
18:23:41,040 --> 18:23:42,040
exam maybe one question but it's not
25588
18:23:44,280 --> 18:23:45,280
really worth going into depth because
25589
18:23:45,900 --> 18:23:46,900
that's what Security Plus is going to do
25590
18:23:47,936 --> 18:23:48,936
and when you talk about Security Plus
25591
18:23:49,680 --> 18:23:50,680
you're really going to talk about these
25592
18:23:51,540 --> 18:23:52,540
nip Security in more depth then
25593
18:23:55,196 --> 18:23:56,196
and there are a few benefits and
25594
18:23:56,696 --> 18:23:57,696
services that ipsec protocols provide
25595
18:23:59,156 --> 18:24:00,156
the first service is data verification
25596
18:24:03,000 --> 18:24:04,000
this service ensures that the data that
25597
18:24:06,180 --> 18:24:07,180
is being sent across the network is
25598
18:24:08,280 --> 18:24:09,280
coming from a legitimate Source or
25599
18:24:10,920 --> 18:24:11,920
legitimate place
25600
18:24:12,780 --> 18:24:13,780
they make sure that the end users are
25601
18:24:15,836 --> 18:24:16,836
the intended users and to keep an eye on
25602
18:24:17,820 --> 18:24:18,820
packets as they travel across the
25603
18:24:19,500 --> 18:24:20,500
network
25604
18:24:20,460 --> 18:24:21,460
the next service that ipsec is going to
25605
18:24:22,860 --> 18:24:23,860
provide is protection from data
25606
18:24:25,196 --> 18:24:26,196
tampering again that integrity
25607
18:24:28,744 --> 18:24:29,744
service make sure that while data is in
25608
18:24:30,836 --> 18:24:31,836
transit nothing changes this could mean
25609
18:24:33,244 --> 18:24:34,244
the data somehow becomes corrupted or
25610
18:24:35,756 --> 18:24:36,756
that someone literally tampers with it
25611
18:24:37,616 --> 18:24:38,616
again while ipsec protocols provide
25612
18:24:40,256 --> 18:24:41,256
secure Communications within the network
25613
18:24:42,116 --> 18:24:43,116
they don't actually stop an attacker
25614
18:24:44,100 --> 18:24:45,100
from entering the network so while there
25615
18:24:46,016 --> 18:24:47,016
is a chance of an attacker on the
25616
18:24:47,580 --> 18:24:48,580
network they can't tamper with the data
25617
18:24:49,976 --> 18:24:50,976
as it travels through because ipsec is
25618
18:24:52,320 --> 18:24:53,320
going to make sure that doesn't happen
25619
18:24:54,064 --> 18:24:55,064
finally ipsec provides private
25620
18:24:57,476 --> 18:24:58,476
transactions over the network this means
25621
18:25:00,000 --> 18:25:01,000
that data is unreadable by everyone
25622
18:25:02,400 --> 18:25:03,400
except the end users this is where that
25623
18:25:05,040 --> 18:25:06,040
authentication comes in and where
25624
18:25:07,196 --> 18:25:08,196
confidentiality comes into play
25625
18:25:10,140 --> 18:25:11,140
for example if Mike and Steve have to
25626
18:25:12,180 --> 18:25:13,180
send some private banking information to
25627
18:25:13,976 --> 18:25:14,976
each other the service makes sure that
25628
18:25:15,900 --> 18:25:16,900
Mike and Steve were the only people who
25629
18:25:17,820 --> 18:25:18,820
can read it this isn't happening at any
25630
18:25:19,920 --> 18:25:20,920
level that you can see it's happening
25631
18:25:22,320 --> 18:25:23,320
all within the protocols that already
25632
18:25:24,116 --> 18:25:25,116
exist when we talked much earlier about
25633
18:25:27,436 --> 18:25:28,436
ipv4 versus
25634
18:25:29,960 --> 18:25:30,960
IPv6 one of the great benefits of IPv6
25635
18:25:33,540 --> 18:25:34,540
is it has all the ipsec stuff built in
25636
18:25:36,420 --> 18:25:37,420
so all of this is happening
25637
18:25:38,540 --> 18:25:39,540
automatically within our new version of
25638
18:25:41,296 --> 18:25:42,296
IPv6 it's not even something we need to
25639
18:25:43,860 --> 18:25:44,860
really worry about just something we
25640
18:25:45,476 --> 18:25:46,476
need to know is taking place so we can
25641
18:25:47,336 --> 18:25:48,336
be a little more sure that our data is
25642
18:25:49,196 --> 18:25:50,196
actually being secured
25643
18:25:51,296 --> 18:25:52,296
so here is what ipsec might look like if
25644
18:25:54,720 --> 18:25:55,720
they were connecting two lands to make a
25645
18:25:56,820 --> 18:25:57,820
Wan
25646
18:25:57,720 --> 18:25:58,720
though the two networks have their own
25647
18:25:59,756 --> 18:26:00,756
firewalls and Protection Systems they
25648
18:26:01,976 --> 18:26:02,976
still have to connect the Republic
25649
18:26:03,180 --> 18:26:04,180
Network which we know isn't the safest
25650
18:26:05,040 --> 18:26:06,040
thing this is especially true in the
25651
18:26:07,196 --> 18:26:08,196
public network is the internet
25652
18:26:10,256 --> 18:26:11,256
Now using ipsec the two lands are going
25653
18:26:13,320 --> 18:26:14,320
to create a tunnel of communication
25654
18:26:14,936 --> 18:26:15,936
through the network or through the
25655
18:26:16,680 --> 18:26:17,680
internet this tunnel is secure and only
25656
18:26:19,140 --> 18:26:20,140
accessible by people inside their
25657
18:26:21,064 --> 18:26:22,064
Network the is ipsec tunnel by the way
25658
18:26:24,244 --> 18:26:25,244
is what we're referring to when we talk
25659
18:26:26,220 --> 18:26:27,220
about VPN or virtual private Networks
25660
18:26:29,756 --> 18:26:30,756
so when we set up ipsec the service
25661
18:26:32,400 --> 18:26:33,400
doesn't just configure itself
25662
18:26:34,756 --> 18:26:35,756
necessarily there's some things that
25663
18:26:37,140 --> 18:26:38,140
have to be put into place for the
25664
18:26:38,516 --> 18:26:39,516
services to run properly these are
25665
18:26:40,436 --> 18:26:41,436
called policies and policies is what
25666
18:26:45,180 --> 18:26:46,180
configures the services that ipsec
25667
18:26:47,280 --> 18:26:48,280
provides they're used to provide
25668
18:26:49,080 --> 18:26:50,080
different levels of protection data and
25669
18:26:51,600 --> 18:26:52,600
connections based on what in getting
25670
18:26:53,280 --> 18:26:54,280
what is getting passed through them in
25671
18:26:55,616 --> 18:26:56,616
other words just like with passwords we
25672
18:26:58,256 --> 18:26:59,256
have the passwords and we know they're
25673
18:26:59,580 --> 18:27:00,580
built into windows but unless we set
25674
18:27:02,156 --> 18:27:03,156
some sort of policy that tells the users
25675
18:27:05,400 --> 18:27:06,400
how their passwords have to function
25676
18:27:07,080 --> 18:27:08,080
they may not be used very well someone
25677
18:27:09,476 --> 18:27:10,476
might just use the password password
25678
18:27:11,220 --> 18:27:12,220
which isn't even a safe password so we
25679
18:27:13,920 --> 18:27:14,920
have a password policy that ensures that
25680
18:27:16,500 --> 18:27:17,500
people have a certain length uh history
25681
18:27:19,320 --> 18:27:20,320
and certain characters included in their
25682
18:27:21,656 --> 18:27:22,656
passwords the same thing sort of goes
25683
18:27:23,460 --> 18:27:24,460
with ipsec
25684
18:27:24,900 --> 18:27:25,900
now there are some important elements
25685
18:27:27,180 --> 18:27:28,180
that we have to address when setting up
25686
18:27:29,876 --> 18:27:30,876
ipsec policies first we have filters
25687
18:27:33,180 --> 18:27:34,180
that are put into place the filters
25688
18:27:35,220 --> 18:27:36,220
determine which packets should be secure
25689
18:27:38,756 --> 18:27:39,756
and which can be left alone
25690
18:27:42,000 --> 18:27:43,000
now every filter addresses a different
25691
18:27:43,976 --> 18:27:44,976
type of packet so there's generally a
25692
18:27:46,320 --> 18:27:47,320
good amount of different types of
25693
18:27:47,640 --> 18:27:48,640
filters all of these filters get
25694
18:27:50,756 --> 18:27:51,756
compiled into a filter list where the
25695
18:27:52,976 --> 18:27:53,976
administrator can easily change and
25696
18:27:54,720 --> 18:27:55,720
reconfigure the filters to address the
25697
18:27:56,640 --> 18:27:57,640
needs of their Network now again the
25698
18:27:58,744 --> 18:27:59,744
reason we're going to want to have
25699
18:27:59,756 --> 18:28:00,756
filters is because the more security
25700
18:28:05,696 --> 18:28:06,696
just like the more layers you have on if
25701
18:28:08,640 --> 18:28:09,640
it's cold outside
25702
18:28:11,820 --> 18:28:12,820
the more data it takes up
25703
18:28:14,220 --> 18:28:15,220
and the longer it takes to decode so the
25704
18:28:17,640 --> 18:28:18,640
less security we have the faster the
25705
18:28:19,920 --> 18:28:20,920
data is going to travel but the more
25706
18:28:22,376 --> 18:28:23,376
security uh the less easy it is to
25707
18:28:25,500 --> 18:28:26,500
tamper with so we need to weigh this
25708
18:28:27,116 --> 18:28:28,116
stuff like browsing on the internet
25709
18:28:28,744 --> 18:28:29,744
might not be something we need to secure
25710
18:28:30,420 --> 18:28:31,420
a lot whereas we probably want to secure
25711
18:28:33,256 --> 18:28:34,256
uh for instance email a lot more or even
25712
18:28:36,600 --> 18:28:37,600
Bank Social Security numbers
25713
18:28:38,820 --> 18:28:39,820
etc etc
25714
18:28:40,376 --> 18:28:41,376
next policies have to be provided the
25715
18:28:43,376 --> 18:28:44,376
proper Network information this involves
25716
18:28:46,196 --> 18:28:47,196
what security map methods connection
25717
18:28:48,064 --> 18:28:49,064
types and tunnel settings are being used
25718
18:28:50,640 --> 18:28:51,640
the security methods are basically
25719
18:28:53,296 --> 18:28:54,296
algorithms that are used in encrypting
25720
18:28:58,616 --> 18:28:59,616
and authenticating the data connection
25721
18:29:01,436 --> 18:29:02,436
types determine whether the policies are
25722
18:29:04,320 --> 18:29:05,320
going to handle
25723
18:29:05,936 --> 18:29:06,936
a local area network
25724
18:29:08,280 --> 18:29:09,280
a Wan or a VPN
25725
18:29:11,220 --> 18:29:12,220
in other words ipsec needs to know what
25726
18:29:14,336 --> 18:29:15,336
type of connection I have here so it
25727
18:29:17,516 --> 18:29:18,516
knows what level of security to put into
25728
18:29:19,616 --> 18:29:20,616
place you can imagine that with a wide
25729
18:29:22,376 --> 18:29:23,376
area network or VPN we need more
25730
18:29:24,780 --> 18:29:25,780
security than with a lan
25731
18:29:28,140 --> 18:29:29,140
all right so although this might have
25732
18:29:30,244 --> 18:29:31,244
been short duration we covered a lot of
25733
18:29:32,336 --> 18:29:33,336
important things first we talked about
25734
18:29:34,860 --> 18:29:35,860
the fact that ipsec exists remember
25735
18:29:37,696 --> 18:29:38,696
ipsec stands for IP security and it's
25736
18:29:42,180 --> 18:29:43,180
really not its own protocol what it is
25737
18:29:45,836 --> 18:29:46,836
is a series or a group of protocols
25738
18:29:49,436 --> 18:29:50,436
Services
25739
18:29:51,540 --> 18:29:52,540
Etc that ensure security over the IP
25740
18:29:56,280 --> 18:29:57,280
protocol or the Internet Protocol
25741
18:30:00,000 --> 18:30:01,000
we also talked about two of the ways we
25742
18:30:02,460 --> 18:30:03,460
do this one is the ah protocol and one
25743
18:30:05,100 --> 18:30:06,100
is the ESP protocol remember ah stands
25744
18:30:09,420 --> 18:30:10,420
for authentication header
25745
18:30:12,180 --> 18:30:13,180
as the name implies it's a header in the
25746
18:30:15,180 --> 18:30:16,180
IP packet that authenticates
25747
18:30:19,500 --> 18:30:20,500
to make sure the users who are about to
25748
18:30:22,016 --> 18:30:23,016
communicate are the ones for whom it's
25749
18:30:23,756 --> 18:30:24,756
intended and who are sending
25750
18:30:25,680 --> 18:30:26,680
ESP on the other hand which stands for
25751
18:30:28,680 --> 18:30:29,680
encapsulating
25752
18:30:34,256 --> 18:30:35,256
security payload
25753
18:30:39,476 --> 18:30:40,476
is literally going to encapsulate the
25754
18:30:42,244 --> 18:30:43,244
data in an encrypted form
25755
18:30:45,420 --> 18:30:46,420
and it'll only release this encrypted
25756
18:30:47,460 --> 18:30:48,460
information to someone who has been
25757
18:30:49,976 --> 18:30:50,976
authenticated to receive it and remember
25758
18:30:52,436 --> 18:30:53,436
to do this we use Keys both public and
25759
18:30:56,400 --> 18:30:57,400
private
25760
18:31:01,196 --> 18:31:02,196
we also discussed the three different
25761
18:31:03,296 --> 18:31:04,296
ipsec services that are provided
25762
18:31:05,656 --> 18:31:06,656
including data verification which
25763
18:31:08,696 --> 18:31:09,696
ensures that the data packets being sent
25764
18:31:12,180 --> 18:31:13,180
are coming from legitimate places
25765
18:31:17,280 --> 18:31:18,280
protection from tampering which ensures
25766
18:31:19,920 --> 18:31:20,920
the integrity
25767
18:31:21,900 --> 18:31:22,900
of our data that it has not been
25768
18:31:23,696 --> 18:31:24,696
tampered with either
25769
18:31:26,756 --> 18:31:27,756
tampered with from say an attacker
25770
18:31:30,720 --> 18:31:31,720
or the data might have just become
25771
18:31:33,000 --> 18:31:34,000
corrupted
25772
18:31:35,100 --> 18:31:36,100
finally we ensure that we're having
25773
18:31:37,140 --> 18:31:38,140
private transactions meaning that the
25774
18:31:40,564 --> 18:31:41,564
data is confidential between only the
25775
18:31:43,320 --> 18:31:44,320
people who need to be having it and
25776
18:31:45,296 --> 18:31:46,296
lastly we discussed ipsec policies some
25777
18:31:48,180 --> 18:31:49,180
of the things that we need to have when
25778
18:31:50,876 --> 18:31:51,876
we're creating our policies for IP
25779
18:31:53,336 --> 18:31:54,336
security for instance we need to know
25780
18:31:55,680 --> 18:31:56,680
the type of network we're on
25781
18:32:00,420 --> 18:32:01,420
and also filters
25782
18:32:02,280 --> 18:32:03,280
so that the appropriate level of
25783
18:32:04,796 --> 18:32:05,796
security can be applied to the
25784
18:32:06,180 --> 18:32:07,180
appropriate type of data
25785
18:32:11,360 --> 18:32:12,360
[Music]
25786
18:32:27,656 --> 18:32:28,656
welcome to module 14 lesson 1 denial of
25787
18:32:30,900 --> 18:32:31,900
service
25788
18:32:34,140 --> 18:32:35,140
so we're going to look at what is denial
25789
18:32:36,000 --> 18:32:37,000
of service by the way this is a small uh
25790
18:32:38,820 --> 18:32:39,820
subset of what you would get in the
25791
18:32:40,564 --> 18:32:41,564
competitive Security Plus exam and and
25792
18:32:44,516 --> 18:32:45,516
the network plus
25793
18:32:46,016 --> 18:32:47,016
um sorry the CCNA security exam those
25794
18:32:48,836 --> 18:32:49,836
are the vendors do security as well
25795
18:32:50,460 --> 18:32:51,460
obviously like a juniper but um company
25796
18:32:53,400 --> 18:32:54,400
is a good foundation and then in Vendor
25797
18:32:55,976 --> 18:32:56,976
specific Cisco CCNA security is
25798
18:32:58,860 --> 18:32:59,860
excellent you probably I think you need
25799
18:33:01,256 --> 18:33:02,256
to do the CC and a first or at least one
25800
18:33:03,600 --> 18:33:04,600
of the CCNA exams the um icnd one would
25801
18:33:08,100 --> 18:33:09,100
do check so what is it bandwidth attacks
25802
18:33:10,976 --> 18:33:11,976
connectivity attacks common types of
25803
18:33:13,376 --> 18:33:14,376
denial of service attacks what is
25804
18:33:16,100 --> 18:33:17,100
distributed denial of service
25805
18:33:20,220 --> 18:33:21,220
types of those difference between a
25806
18:33:23,460 --> 18:33:24,460
denial of service and distributed
25807
18:33:26,000 --> 18:33:27,000
reflective dos attack and then types of
25808
18:33:29,876 --> 18:33:30,876
reflective unintentional
25809
18:33:31,550 --> 18:33:32,550
[Music]
25810
18:33:32,936 --> 18:33:33,936
physical infrastructure attacks and how
25811
18:33:35,580 --> 18:33:36,580
to prevent how to identify denial of
25812
18:33:38,640 --> 18:33:39,640
service attack just bear in mind this is
25813
18:33:40,616 --> 18:33:41,616
an overview so you need some fairly
25814
18:33:42,476 --> 18:33:43,476
specific training on um hardening your
25815
18:33:45,960 --> 18:33:46,960
network and also identifying and
25816
18:33:48,656 --> 18:33:49,656
troubleshooting and resolving the denial
25817
18:33:51,900 --> 18:33:52,900
service attack
25818
18:33:53,580 --> 18:33:54,580
so what is it basically refers to an
25819
18:33:56,336 --> 18:33:57,336
attack on a computer network to make its
25820
18:33:58,616 --> 18:33:59,616
services unavailable to legitimate users
25821
18:34:02,516 --> 18:34:03,516
you've heard of it I'm sure in the Press
25822
18:34:05,936 --> 18:34:06,936
um
25823
18:34:07,320 --> 18:34:08,320
before some big big companies have been
25824
18:34:09,780 --> 18:34:10,780
attacked before Delilah service
25825
18:34:11,820 --> 18:34:12,820
basically attacks the network with
25826
18:34:13,744 --> 18:34:14,744
useless traffic
25827
18:34:16,080 --> 18:34:17,080
it's a type of cyber threat
25828
18:34:19,564 --> 18:34:20,564
so what do the denial attackers actually
25829
18:34:21,900 --> 18:34:22,900
put their effort into doing preventing
25830
18:34:25,196 --> 18:34:26,196
um legitimate users such as members of
25831
18:34:27,180 --> 18:34:28,180
the public or employees from accessing
25832
18:34:30,720 --> 18:34:31,720
Network Services
25833
18:34:32,180 --> 18:34:33,180
emails websites online banking Etc
25834
18:34:37,696 --> 18:34:38,696
usually the denial of service attacks
25835
18:34:41,040 --> 18:34:42,040
occur when the attacker floods a
25836
18:34:42,836 --> 18:34:43,836
particular network with a huge amount of
25837
18:34:44,820 --> 18:34:45,820
traffic
25838
18:34:46,196 --> 18:34:47,196
so for example to access a website we
25839
18:34:48,180 --> 18:34:49,180
type in the URL you send a request to
25840
18:34:50,336 --> 18:34:51,336
the web server
25841
18:34:52,256 --> 18:34:53,256
web server can only process a limited
25842
18:34:54,600 --> 18:34:55,600
number of requests at a given time now
25843
18:34:57,180 --> 18:34:58,180
there's a whole bunch of things that can
25844
18:34:58,616 --> 18:34:59,616
go on for example uh load balancing and
25845
18:35:02,696 --> 18:35:03,696
then CDN cloning the uh website copies
25846
18:35:06,780 --> 18:35:07,780
all over the web but even so
25847
18:35:08,836 --> 18:35:09,836
and there's only a finite amount of
25848
18:35:11,756 --> 18:35:12,756
resources dedicated to all these
25849
18:35:14,696 --> 18:35:15,696
Solutions and they can be used up
25850
18:35:18,900 --> 18:35:19,900
when the attacker burdens the server
25851
18:35:20,640 --> 18:35:21,640
we're too many requests the web server
25852
18:35:22,196 --> 18:35:23,196
is unable to process the legitimate ones
25853
18:35:24,600 --> 18:35:25,600
as a result you can't access it and
25854
18:35:27,360 --> 18:35:28,360
that's called the denial of service
25855
18:35:29,936 --> 18:35:30,936
good you can then Google denial of
25856
18:35:32,100 --> 18:35:33,100
service attacks and look at all the news
25857
18:35:33,656 --> 18:35:34,656
stories over the past few years
25858
18:35:38,420 --> 18:35:39,420
and messages to establish a similar
25859
18:35:41,336 --> 18:35:42,336
attack only limited the number of emails
25860
18:35:44,040 --> 18:35:45,040
are allowed in your corporate accounts
25861
18:35:45,900 --> 18:35:46,900
usually mind you even large
25862
18:35:49,016 --> 18:35:50,016
um free providers like Gmail have got a
25863
18:35:52,436 --> 18:35:53,436
limited amount of um storage
25864
18:35:56,400 --> 18:35:57,400
so as a result the attacker can stop the
25865
18:35:58,744 --> 18:35:59,744
users getting legitimate access to their
25866
18:36:01,616 --> 18:36:02,616
account
25867
18:36:03,000 --> 18:36:04,000
and in an email bomb the denial of
25868
18:36:05,336 --> 18:36:06,336
service attack the attacker send a lot
25869
18:36:07,140 --> 18:36:08,140
of spam emails and they disable the
25870
18:36:08,820 --> 18:36:09,820
actual email server rather than just an
25871
18:36:11,156 --> 18:36:12,156
account on the server
25872
18:36:14,156 --> 18:36:15,156
generally not concerned with stealing
25873
18:36:16,376 --> 18:36:17,376
information it's just quite an
25874
18:36:17,756 --> 18:36:18,756
aggressive way of bringing down a
25875
18:36:19,320 --> 18:36:20,320
particular service
25876
18:36:21,116 --> 18:36:22,116
it could be a person a business or an
25877
18:36:23,640 --> 18:36:24,640
entire company
25878
18:36:25,436 --> 18:36:26,436
they can attack and Destroy files in
25879
18:36:27,244 --> 18:36:28,244
affected computer system or Network
25880
18:36:30,720 --> 18:36:31,720
and some situations the Denali service
25881
18:36:33,064 --> 18:36:34,064
stack actually affects the website
25882
18:36:35,516 --> 18:36:36,516
um accessed by the users
25883
18:36:38,516 --> 18:36:39,516
most uh denial of service attacks are
25884
18:36:40,920 --> 18:36:41,920
aimed at the computers Network bandwidth
25885
18:36:43,256 --> 18:36:44,256
connectivity
25886
18:36:44,696 --> 18:36:45,696
our resources also server resources
25887
18:36:49,616 --> 18:36:50,616
bandwidth attacks on the computer or
25888
18:36:51,836 --> 18:36:52,836
network with a huge amount of traffic
25889
18:36:53,460 --> 18:36:54,460
huge burst of traffic legitimate users
25890
18:36:56,696 --> 18:36:57,696
can't access every network resources
25891
18:37:01,196 --> 18:37:02,196
the connectivity attacks harm the
25892
18:37:03,116 --> 18:37:04,116
computer with a large amount of
25893
18:37:04,976 --> 18:37:05,976
connection requests
25894
18:37:07,320 --> 18:37:08,320
available operating system resources are
25895
18:37:09,960 --> 18:37:10,960
quickly consumed and the computers
25896
18:37:11,936 --> 18:37:12,936
enable once again to perform legitimate
25897
18:37:14,400 --> 18:37:15,400
requests
25898
18:37:16,196 --> 18:37:17,196
another common type of denial of service
25899
18:37:18,360 --> 18:37:19,360
attack is a buffer overflow all devices
25900
18:37:21,000 --> 18:37:22,000
routers switches have buffers that
25901
18:37:24,296 --> 18:37:25,296
manage a temporary
25902
18:37:26,244 --> 18:37:27,244
excess amount of traffic
25903
18:37:29,100 --> 18:37:30,100
send and receive buffers and if these
25904
18:37:31,436 --> 18:37:32,436
buffers are actually overflowed then
25905
18:37:32,820 --> 18:37:33,820
depending on how the devices are
25906
18:37:34,860 --> 18:37:35,860
configured and what it is then it's
25907
18:37:36,420 --> 18:37:37,420
going to cause problems and packet loss
25908
18:37:39,000 --> 18:37:40,000
the sin attacks teardrop attack
25909
18:37:43,196 --> 18:37:44,196
Smurf attacks viruses a whole bunch
25910
18:37:46,616 --> 18:37:47,616
actually
25911
18:37:47,696 --> 18:37:48,696
the buffer overflow is the most used
25912
18:37:49,936 --> 18:37:50,936
distributes of a huge led to a network
25913
18:37:51,960 --> 18:37:52,960
more than the um buffer is um able to
25914
18:37:55,744 --> 18:37:56,744
handle
25915
18:37:57,244 --> 18:37:58,244
when the attacker has awareness about
25916
18:37:58,796 --> 18:37:59,796
the weaknesses of the target system or
25917
18:38:00,600 --> 18:38:01,600
network that's when you'll get a buffer
25918
18:38:02,220 --> 18:38:03,220
overflow attack and they can Target
25919
18:38:05,516 --> 18:38:06,516
certain vendors or certain devices such
25920
18:38:08,876 --> 18:38:09,876
as Cisco routers or uh the vendors
25921
18:38:12,116 --> 18:38:13,116
firewalls Etc
25922
18:38:14,280 --> 18:38:15,280
once when the attacker simply tries to
25923
18:38:16,016 --> 18:38:17,016
attack not knowing whether it's going to
25924
18:38:17,400 --> 18:38:18,400
work so it's a quite a Brute Force
25925
18:38:19,680 --> 18:38:20,680
attack
25926
18:38:20,516 --> 18:38:21,516
but for attacks are based on the system
25927
18:38:22,256 --> 18:38:23,256
or programs above their characteristics
25928
18:38:26,756 --> 18:38:27,756
and other way distribute emails
25929
18:38:28,920 --> 18:38:29,920
including 256 character file names which
25930
18:38:31,800 --> 18:38:32,800
all take a matter of amount of time to
25931
18:38:33,960 --> 18:38:34,960
process so the huge icmp packets
25932
18:38:38,784 --> 18:38:39,784
email messages including a from
25933
18:38:41,104 --> 18:38:42,104
statement that is more characters than
25934
18:38:43,464 --> 18:38:44,464
256 seems to be the limit for emails
25935
18:38:50,400 --> 18:38:51,400
now this is a sin and synark which you
25936
18:38:52,744 --> 18:38:53,744
should be familiar with from the network
25937
18:38:55,376 --> 18:38:56,376
of a plus and and the other network
25938
18:38:58,496 --> 18:38:59,496
research you've done this is what
25939
18:38:59,936 --> 18:39:00,936
happens before a connection can actually
25940
18:39:02,040 --> 18:39:03,040
take place if you're using TCP
25941
18:39:05,104 --> 18:39:06,104
so with a cell attack the attacker sends
25942
18:39:07,504 --> 18:39:08,504
a TCP connection request faster than the
25943
18:39:09,784 --> 18:39:10,784
Target computers processing speed using
25944
18:39:13,192 --> 18:39:14,192
client server technology it begins to
25945
18:39:15,832 --> 18:39:16,832
establish a three-way handshake
25946
18:39:18,296 --> 18:39:19,296
so you'd have a sin sinach sin and there
25947
18:39:21,600 --> 18:39:22,600
should be an acknowledgment happens
25948
18:39:23,216 --> 18:39:24,216
before the data sent
25949
18:39:26,040 --> 18:39:27,040
that doesn't actually happen
25950
18:39:28,680 --> 18:39:29,680
so client sends a collection
25951
18:39:30,176 --> 18:39:31,176
establishment using the sin synchronized
25952
18:39:32,336 --> 18:39:33,336
message
25953
18:39:33,480 --> 18:39:34,480
a server can then send a sin
25954
18:39:36,240 --> 18:39:37,240
synchronization acknowledgment client
25955
18:39:38,936 --> 18:39:39,936
responds with an act an act message and
25956
18:39:41,336 --> 18:39:42,336
the connection is then established
25957
18:39:43,440 --> 18:39:44,440
if the attacker sends repetitive sin
25958
18:39:46,744 --> 18:39:47,744
packets to every port using a fake IP
25959
18:39:49,504 --> 18:39:50,504
address the server establishes
25960
18:39:51,480 --> 18:39:52,480
Communications
25961
18:39:53,336 --> 18:39:54,336
and responds to all requests and what it
25962
18:39:55,504 --> 18:39:56,504
also does is it leaves a
25963
18:39:57,896 --> 18:39:58,896
a window open for the actual
25964
18:40:00,144 --> 18:40:01,144
Communications to take place so for each
25965
18:40:03,120 --> 18:40:04,120
request in request for a certain period
25966
18:40:05,640 --> 18:40:06,640
of time depending on the traffic it will
25967
18:40:08,640 --> 18:40:09,640
um Reserve resources
25968
18:40:11,040 --> 18:40:12,040
replies to each attempt with a synap
25969
18:40:13,080 --> 18:40:14,080
packet from every open port
25970
18:40:16,016 --> 18:40:17,016
okay teardrop account attack sends
25971
18:40:18,960 --> 18:40:19,960
fragmented packets to a Target computer
25972
18:40:22,376 --> 18:40:23,376
when the computer receives the packets
25973
18:40:24,240 --> 18:40:25,240
it's enabled to reassemble them because
25974
18:40:25,976 --> 18:40:26,976
of the following
25975
18:40:27,240 --> 18:40:28,240
a bug in the TCP fragment reassembly
25976
18:40:31,192 --> 18:40:32,192
overlapping packets
25977
18:40:33,296 --> 18:40:34,296
crashing of network devices
25978
18:40:36,120 --> 18:40:37,120
can usually happen on older operating
25979
18:40:38,104 --> 18:40:39,104
systems some of you might remember these
25980
18:40:40,616 --> 18:40:41,616
three Windows 3.1 Windows 95
25981
18:40:45,176 --> 18:40:46,176
Windows NT and some versions of fair
25982
18:40:48,240 --> 18:40:49,240
Linux
25983
18:40:51,176 --> 18:40:52,176
some Earth attacks is where the attacker
25984
18:40:52,920 --> 18:40:53,920
fluids the victim's computer with ping
25985
18:40:54,656 --> 18:40:55,656
packets the attack initiates the attack
25986
18:40:57,296 --> 18:40:58,296
by sending a ping request and then
25987
18:40:59,640 --> 18:41:00,640
spoofs the destination address ping
25988
18:41:01,920 --> 18:41:02,920
replies are sent to the victim's
25989
18:41:03,536 --> 18:41:04,536
computer address
25990
18:41:07,616 --> 18:41:08,616
since the Ping request is addressed to
25991
18:41:09,784 --> 18:41:10,784
the broadcast address all computers in
25992
18:41:11,576 --> 18:41:12,576
the network have to respond and
25993
18:41:14,464 --> 18:41:15,464
um each packet is opened and checked and
25994
18:41:17,280 --> 18:41:18,280
to see if it's the destination
25995
18:41:20,760 --> 18:41:21,760
as a result the victim can't receive any
25996
18:41:22,800 --> 18:41:23,800
genuine traffic because it's already
25997
18:41:24,296 --> 18:41:25,296
flooded with ping packets
25998
18:41:28,192 --> 18:41:29,192
uh technique of assigning a network
25999
18:41:29,936 --> 18:41:30,936
packet with a file side P address is
26000
18:41:31,920 --> 18:41:32,920
called spoofing
26001
18:41:36,360 --> 18:41:37,360
computer viruses these are distributed
26002
18:41:38,640 --> 18:41:39,640
and spread throughout the network in a
26003
18:41:40,560 --> 18:41:41,560
number of ways
26004
18:41:44,760 --> 18:41:45,760
the attacker uses and controls the
26005
18:41:46,560 --> 18:41:47,560
victim's computer to attack somebody
26006
18:41:48,064 --> 18:41:49,064
else's low and weak uh security network
26007
18:41:51,832 --> 18:41:52,832
security and some device some devices
26008
18:41:54,240 --> 18:41:55,240
you're waiting to have patches applied
26009
18:41:56,760 --> 18:41:57,760
to or they haven't rebooted after up and
26010
18:41:59,576 --> 18:42:00,576
downloading some updates or whatever and
26011
18:42:01,320 --> 18:42:02,320
this is when they become vulnerable
26012
18:42:03,720 --> 18:42:04,720
attacker floods they target competes
26013
18:42:05,512 --> 18:42:06,512
with a huge amount of data to a
26014
18:42:06,960 --> 18:42:07,960
particular site or spam emails using a
26015
18:42:09,784 --> 18:42:10,784
victim's computer so the name
26016
18:42:11,936 --> 18:42:12,936
distributed indicates the attacker uses
26017
18:42:14,576 --> 18:42:15,576
multiple host computers
26018
18:42:16,744 --> 18:42:17,744
uh this is to throw
26019
18:42:18,896 --> 18:42:19,896
um others off the trail and make it
26020
18:42:21,176 --> 18:42:22,176
harder to actually identify the attack
26021
18:42:23,336 --> 18:42:24,336
because the um victims are actually
26022
18:42:25,616 --> 18:42:26,616
legitimate systems on the hosts
26023
18:42:28,800 --> 18:42:29,800
the attacker can increase the
26024
18:42:30,240 --> 18:42:31,240
effectiveness using client server
26025
18:42:31,976 --> 18:42:32,976
technology
26026
18:42:33,536 --> 18:42:34,536
in distributed denial of service
26027
18:42:36,240 --> 18:42:37,240
master program or software is installed
26028
18:42:38,400 --> 18:42:39,400
on one computer normally they use a
26029
18:42:41,464 --> 18:42:42,464
stolen login credentials
26030
18:42:44,824 --> 18:42:45,824
now it may not happen immediately but at
26031
18:42:47,936 --> 18:42:48,936
some particular time the master program
26032
18:42:49,696 --> 18:42:50,696
communicates with other agent programs
26033
18:42:51,784 --> 18:42:52,784
that install the computers anywhere on
26034
18:42:53,640 --> 18:42:54,640
the internet
26035
18:42:54,656 --> 18:42:55,656
when the ages receive their command they
26036
18:42:56,760 --> 18:42:57,760
start to attack
26037
18:42:59,280 --> 18:43:00,280
the master program is able to spread
26038
18:43:01,504 --> 18:43:02,504
thousands of agent programs within
26039
18:43:03,240 --> 18:43:04,240
seconds using client server technology
26040
18:43:10,256 --> 18:43:11,256
so some characteristics of distributed
26041
18:43:13,080 --> 18:43:14,080
denial of service attacks a botnet
26042
18:43:15,784 --> 18:43:16,784
traffic spite coordinated attack
26043
18:43:20,824 --> 18:43:21,824
so if you can see that there's a
26044
18:43:22,496 --> 18:43:23,496
attacking machine at the top there and
26045
18:43:24,176 --> 18:43:25,176
handlers and compromise systems
26046
18:43:28,144 --> 18:43:29,144
um going down to the targeted services
26047
18:43:29,760 --> 18:43:30,760
or servers on the bottom there
26048
18:43:32,464 --> 18:43:33,464
so botnet refers to a group of computers
26049
18:43:34,800 --> 18:43:35,800
that can cooperate
26050
18:43:37,376 --> 18:43:38,376
also known as zombies in this context
26051
18:43:42,000 --> 18:43:43,000
at the botnet owners also known as
26052
18:43:43,800 --> 18:43:44,800
herders they manage computers in their
26053
18:43:45,784 --> 18:43:46,784
botnet botners used to send spam emails
26054
18:43:48,832 --> 18:43:49,832
or to participate in distributed denial
26055
18:43:50,936 --> 18:43:51,936
of service attack
26056
18:43:52,376 --> 18:43:53,376
so this is why it can be so difficult
26057
18:43:54,536 --> 18:43:55,536
because all these legitimate devices at
26058
18:43:57,480 --> 18:43:58,480
some point of time when there's a
26059
18:43:58,856 --> 18:43:59,856
trigger it's a like a timer or it's time
26060
18:44:01,856 --> 18:44:02,856
when everyone's off work or on a
26061
18:44:04,192 --> 18:44:05,192
Saturday night on a bank holiday they'll
26062
18:44:06,896 --> 18:44:07,896
start their attack
26063
18:44:09,600 --> 18:44:10,600
traffic spy overloads the victim's
26064
18:44:11,696 --> 18:44:12,696
Network or server in order to
26065
18:44:13,800 --> 18:44:14,800
its services and resources
26066
18:44:15,832 --> 18:44:16,832
as a result the legitimate user will not
26067
18:44:18,120 --> 18:44:19,120
be able to access the service
26068
18:44:21,480 --> 18:44:22,480
they use when people are coordinated to
26069
18:44:23,640 --> 18:44:24,640
carry out the attack on a site or site
26070
18:44:25,616 --> 18:44:26,616
at the same time
26071
18:44:27,480 --> 18:44:28,480
when many people attack the server the
26072
18:44:29,400 --> 18:44:30,400
web Server slows down or gets overloaded
26073
18:44:32,280 --> 18:44:33,280
it's difficult to differentiate such
26074
18:44:34,192 --> 18:44:35,192
attacks from the normal traffic
26075
18:44:37,616 --> 18:44:38,616
where many people do this at a similar
26076
18:44:39,656 --> 18:44:40,656
time the web Server slows down or gets
26077
18:44:41,936 --> 18:44:42,936
overloaded
26078
18:44:43,440 --> 18:44:44,440
uh it's difficult to identify this a
26079
18:44:46,920 --> 18:44:47,920
type of attack from normal traffic that
26080
18:44:48,720 --> 18:44:49,720
can happen and obviously you do get
26081
18:44:50,040 --> 18:44:51,040
spikes on networks and then if there's
26082
18:44:53,040 --> 18:44:54,040
updates been applied
26083
18:44:54,832 --> 18:44:55,832
to the servers again it can
26084
18:44:58,080 --> 18:44:59,080
um appear to be slow legitimately slow
26085
18:45:02,696 --> 18:45:03,696
difference between denial of service and
26086
18:45:04,744 --> 18:45:05,744
distributed
26087
18:45:06,176 --> 18:45:07,176
and using a single internet connection
26088
18:45:08,040 --> 18:45:09,040
an attacker can harm a network in a Dos
26089
18:45:10,496 --> 18:45:11,496
attack
26090
18:45:11,576 --> 18:45:12,576
launching multiple connected devices
26091
18:45:13,744 --> 18:45:14,744
that are distributed is a distributed
26092
18:45:16,376 --> 18:45:17,376
denial of service attack
26093
18:45:19,504 --> 18:45:20,504
uh the distributed another service also
26094
18:45:22,920 --> 18:45:23,920
differs in the attacks that perform
26095
18:45:24,600 --> 18:45:25,600
using botnets
26096
18:45:27,656 --> 18:45:28,656
um including mobile phones routers PCS
26097
18:45:30,360 --> 18:45:31,360
Etc
26098
18:45:31,976 --> 18:45:32,976
Denali service attacks can harm a single
26099
18:45:34,192 --> 18:45:35,192
machine or they can attack an entire
26100
18:45:36,296 --> 18:45:37,296
network
26101
18:45:38,640 --> 18:45:39,640
moving on to the reflective Amplified
26102
18:45:41,400 --> 18:45:42,400
denial of service
26103
18:45:43,744 --> 18:45:44,744
the reflective user third-party machines
26104
18:45:45,832 --> 18:45:46,832
to attack a targeted computer so
26105
18:45:48,424 --> 18:45:49,424
basically the is one way for the
26106
18:45:50,576 --> 18:45:51,576
attacker to mask their identity
26107
18:45:53,936 --> 18:45:54,936
reflective denial service attacks use
26108
18:45:56,160 --> 18:45:57,160
third-party servers for example DNS
26109
18:45:58,496 --> 18:45:59,496
servers to attack a targeted computer
26110
18:46:01,800 --> 18:46:02,800
the attacker sends a requested the
26111
18:46:03,360 --> 18:46:04,360
reflector server or servers with the IP
26112
18:46:05,576 --> 18:46:06,576
address of the target
26113
18:46:07,080 --> 18:46:08,080
and what it does is overpowers the
26114
18:46:09,056 --> 18:46:10,056
target using response packets
26115
18:46:12,896 --> 18:46:13,896
an example is a DNS response
26116
18:46:19,144 --> 18:46:20,144
type of reflective denial of service
26117
18:46:20,872 --> 18:46:21,872
attacks DNS amplification Network time
26118
18:46:24,176 --> 18:46:25,176
protocol smurfing
26119
18:46:27,120 --> 18:46:28,120
mentioned DNS amplification the attack
26120
18:46:30,784 --> 18:46:31,784
explicit DNS server to make
26121
18:46:33,600 --> 18:46:34,600
um change small requests into
26122
18:46:35,336 --> 18:46:36,336
considerably larger payloads this can be
26123
18:46:38,872 --> 18:46:39,872
used to overthrow the victim's servers
26124
18:46:43,144 --> 18:46:44,144
Network time the attacker exploits a
26125
18:46:46,016 --> 18:46:47,016
widely accessible Network time servers
26126
18:46:47,936 --> 18:46:48,936
and destroys the targeted computer with
26127
18:46:50,640 --> 18:46:51,640
UDP traffic which is what ntp uses
26128
18:46:54,896 --> 18:46:55,896
uh can they're not all intentional they
26129
18:46:57,424 --> 18:46:58,424
can be unintentional this is when a
26130
18:46:59,160 --> 18:47:00,160
server crashes for example can't provide
26131
18:47:01,744 --> 18:47:02,744
services because of traffic from
26132
18:47:03,720 --> 18:47:04,720
legitimate users
26133
18:47:05,464 --> 18:47:06,464
uh again have a look there's a whole
26134
18:47:07,744 --> 18:47:08,744
bunch of quite
26135
18:47:09,896 --> 18:47:10,896
um well reported and embarrassing
26136
18:47:11,640 --> 18:47:12,640
examples for government and private
26137
18:47:13,616 --> 18:47:14,616
companies large companies
26138
18:47:15,896 --> 18:47:16,896
so in a popular website hosted news on a
26139
18:47:18,720 --> 18:47:19,720
less equipped secondary site the server
26140
18:47:20,760 --> 18:47:21,760
on that side won't be able to handle the
26141
18:47:22,856 --> 18:47:23,856
traffic especially if there's a big
26142
18:47:24,240 --> 18:47:25,240
breaking news story going on
26143
18:47:28,016 --> 18:47:29,016
a person physically attacks the
26144
18:47:29,640 --> 18:47:30,640
infrastructure of an organization when
26145
18:47:31,376 --> 18:47:32,376
it's a physical attack
26146
18:47:33,360 --> 18:47:34,360
example is they snip or destroy a fiber
26147
18:47:36,056 --> 18:47:37,056
optic cable
26148
18:47:37,616 --> 18:47:38,616
again these I suppose these could be um
26149
18:47:39,784 --> 18:47:40,784
malicious or accidental or known quite a
26150
18:47:42,720 --> 18:47:43,720
few cases of work people cutting through
26151
18:47:44,936 --> 18:47:45,936
cables by accident
26152
18:47:48,296 --> 18:47:49,296
if the attack is able to access the
26153
18:47:49,856 --> 18:47:50,856
compute system
26154
18:47:51,480 --> 18:47:52,480
then they can obtain information on the
26155
18:47:53,336 --> 18:47:54,336
computers obviously
26156
18:47:55,080 --> 18:47:56,080
there's no set way to rescue computers
26157
18:47:59,576 --> 18:48:00,576
or a network from these type of attacks
26158
18:48:02,104 --> 18:48:03,104
you can put into place certain steps to
26159
18:48:05,280 --> 18:48:06,280
reduce the likelihood
26160
18:48:07,320 --> 18:48:08,320
install to maintain an antivirus on your
26161
18:48:10,616 --> 18:48:11,616
end devices you can also have antivirus
26162
18:48:12,960 --> 18:48:13,960
on your
26163
18:48:13,856 --> 18:48:14,856
mobile phones firewalls and computers
26164
18:48:17,216 --> 18:48:18,216
and configure them to control the
26165
18:48:19,016 --> 18:48:20,016
incoming an outgoing traffic
26166
18:48:22,440 --> 18:48:23,440
protect emails from spam they're just
26167
18:48:24,896 --> 18:48:25,896
the latest uh hacking on the Democratic
26168
18:48:27,896 --> 18:48:28,896
National Party actually where a guy
26169
18:48:30,120 --> 18:48:31,120
received a link telling him to reset his
26170
18:48:33,056 --> 18:48:34,056
password and that went off to some
26171
18:48:35,040 --> 18:48:36,040
Russian site allegedly somewhere who
26172
18:48:37,744 --> 18:48:38,744
then got into his system and read all of
26173
18:48:41,104 --> 18:48:42,104
his emails and all the other emails for
26174
18:48:42,832 --> 18:48:43,832
all of the people on the site
26175
18:48:45,784 --> 18:48:46,784
and it will manage unwanted traffic and
26176
18:48:47,936 --> 18:48:48,936
send alerts for spam email messages
26177
18:48:50,872 --> 18:48:51,872
you can install a intrusion detection
26178
18:48:53,824 --> 18:48:54,824
system an IDs that will protect systems
26179
18:48:57,536 --> 18:48:58,536
from the distributed denial of service
26180
18:49:00,360 --> 18:49:01,360
attacks
26181
18:49:03,176 --> 18:49:04,176
the RDS uses collection verification
26182
18:49:05,640 --> 18:49:06,640
methods
26183
18:49:07,144 --> 18:49:08,144
and speak to whatever your network
26184
18:49:09,240 --> 18:49:10,240
equipment vendor is for more information
26185
18:49:12,360 --> 18:49:13,360
you can disable and use networks or
26186
18:49:14,696 --> 18:49:15,696
segments or devices or ports on switches
26187
18:49:17,424 --> 18:49:18,424
regular system performance
26188
18:49:21,536 --> 18:49:22,536
and now you can have legitimate issues
26189
18:49:23,872 --> 18:49:24,872
that represent denial of service like a
26190
18:49:25,800 --> 18:49:26,800
fonty faulty network card a spanning
26191
18:49:28,496 --> 18:49:29,496
tree issue
26192
18:49:29,696 --> 18:49:30,696
a routing protocol convergence when
26193
18:49:31,920 --> 18:49:32,920
you're either booty devices or a network
26194
18:49:33,656 --> 18:49:34,656
has gone down or up
26195
18:49:35,576 --> 18:49:36,576
and large file download by a user on the
26196
18:49:38,336 --> 18:49:39,336
network who doesn't have a limit
26197
18:49:40,552 --> 18:49:41,552
a bulk email sent for marketing for
26198
18:49:42,896 --> 18:49:43,896
example
26199
18:49:45,856 --> 18:49:46,856
unusually slow Network I know and some
26200
18:49:49,504 --> 18:49:50,504
networks I've worked up at for example a
26201
18:49:52,440 --> 18:49:53,440
Friday afternoon there was a big backup
26202
18:49:53,936 --> 18:49:54,936
and the whole network went slow but if
26203
18:49:56,216 --> 18:49:57,216
that happened on another time of the
26204
18:49:57,784 --> 18:49:58,784
week then it could be a warning sign
26205
18:50:00,616 --> 18:50:01,616
unreachability of a particular website
26206
18:50:02,824 --> 18:50:03,824
High numbers of spam messages received
26207
18:50:05,696 --> 18:50:06,696
on an email account
26208
18:50:08,400 --> 18:50:09,400
denial of service oh we've just
26209
18:50:10,920 --> 18:50:11,920
summarizing what we've covered is
26210
18:50:12,176 --> 18:50:13,176
deniala service bandwidth attacks
26211
18:50:14,696 --> 18:50:15,696
connectivity attacks common types of
26212
18:50:17,400 --> 18:50:18,400
deniala service and what is distributed
26213
18:50:19,616 --> 18:50:20,616
to Denali service
26214
18:50:21,656 --> 18:50:22,656
types of distributed attacks the
26215
18:50:24,600 --> 18:50:25,600
difference differences between the two
26216
18:50:27,240 --> 18:50:28,240
reflective denial of service types of
26217
18:50:30,360 --> 18:50:31,360
reflective unintentional
26218
18:50:33,480 --> 18:50:34,480
attacks on our physical infrastructure
26219
18:50:35,464 --> 18:50:36,464
and then preventing denial of service
26220
18:50:37,192 --> 18:50:38,192
and identifying one when it happens so
26221
18:50:40,144 --> 18:50:41,144
that's all for now thanks for watching
26222
18:50:44,650 --> 18:50:45,650
[Music]
26223
18:51:01,800 --> 18:51:02,800
welcome to module 14 lesson 1A common
26224
18:51:04,616 --> 18:51:05,616
networking attacks we've heard earlier
26225
18:51:07,080 --> 18:51:08,080
about a few attacks but we need to just
26226
18:51:09,296 --> 18:51:10,296
update the list because of the new stuff
26227
18:51:11,936 --> 18:51:12,936
in the syllabus
26228
18:51:15,600 --> 18:51:16,600
you can look at Social Engineering
26229
18:51:18,480 --> 18:51:19,480
Insider threats a logic bomb
26230
18:51:21,424 --> 18:51:22,424
Rogue access point Wireless
26231
18:51:24,480 --> 18:51:25,480
evil twin
26232
18:51:26,872 --> 18:51:27,872
War driving could love to know who comes
26233
18:51:29,104 --> 18:51:30,104
up with all of these names
26234
18:51:31,320 --> 18:51:32,320
uh fishing
26235
18:51:33,600 --> 18:51:34,600
around somewhere DNS poisoning ARP
26236
18:51:36,656 --> 18:51:37,656
poisoning spoofing
26237
18:51:38,832 --> 18:51:39,832
de-authentication Brute Force
26238
18:51:42,176 --> 18:51:43,176
VLAN hopping man in the middle
26239
18:51:45,600 --> 18:51:46,600
and then some exploits and
26240
18:51:47,216 --> 18:51:48,216
vulnerabilities social engineering the
26241
18:51:50,280 --> 18:51:51,280
funny thing about this threat is it
26242
18:51:52,144 --> 18:51:53,144
isn't um electronically detectable so we
26243
18:51:55,376 --> 18:51:56,376
don't have a little alarm go off
26244
18:51:58,016 --> 18:51:59,016
somewhere it's um normally when an
26245
18:52:00,600 --> 18:52:01,600
attacker convinces an employee to
26246
18:52:02,936 --> 18:52:03,936
disclose confidential information so
26247
18:52:05,696 --> 18:52:06,696
what happens is uh perhaps they could um
26248
18:52:10,144 --> 18:52:11,144
say they make a phone call that it goes
26249
18:52:12,296 --> 18:52:13,296
through to
26250
18:52:13,744 --> 18:52:14,744
um
26251
18:52:15,256 --> 18:52:16,256
headquarters office and then they
26252
18:52:18,656 --> 18:52:19,656
um they asked to be put through to your
26253
18:52:20,872 --> 18:52:21,872
office so what you'll probably see on
26254
18:52:23,576 --> 18:52:24,576
your phone is the extension one two
26255
18:52:27,896 --> 18:52:28,896
three four as if it's coming from here
26256
18:52:29,760 --> 18:52:30,760
so you think it's an internal call and
26257
18:52:32,336 --> 18:52:33,336
but really it's coming from outside here
26258
18:52:35,040 --> 18:52:36,040
in the um the EU the hackers house
26259
18:52:37,680 --> 18:52:38,680
wherever they may be so it looks like um
26260
18:52:40,856 --> 18:52:41,856
uh the legitimate call
26261
18:52:43,440 --> 18:52:44,440
they pretend to be a senior manager or
26262
18:52:46,016 --> 18:52:47,016
someone inside the tech support
26263
18:52:47,336 --> 18:52:48,336
department
26264
18:52:48,784 --> 18:52:49,784
and um they'll access some information
26265
18:52:51,296 --> 18:52:52,296
they'll ask you for passcodes or say
26266
18:52:53,576 --> 18:52:54,576
there's a problem with your account and
26267
18:52:56,040 --> 18:52:57,040
um this is a pretty successful way of of
26268
18:52:57,960 --> 18:52:58,960
getting information
26269
18:53:00,296 --> 18:53:01,296
the other thing is
26270
18:53:02,104 --> 18:53:03,104
um or accounts are social engineering is
26271
18:53:04,744 --> 18:53:05,744
somebody Who Walks Behind the employee
26272
18:53:08,040 --> 18:53:09,040
who's already entered the security guard
26273
18:53:10,552 --> 18:53:11,552
for a door also known as tailgating
26274
18:53:14,336 --> 18:53:15,336
also another way is leaving the USB
26275
18:53:16,800 --> 18:53:17,800
ground on the USB on the ground
26276
18:53:19,680 --> 18:53:20,680
somewhere this is quite common sometimes
26277
18:53:22,744 --> 18:53:23,744
this these USB sticks have actually got
26278
18:53:25,080 --> 18:53:26,080
a battery in and it's designed whatever
26279
18:53:27,600 --> 18:53:28,600
whatever device you plug it into sends
26280
18:53:30,000 --> 18:53:31,000
an electrical current through it and it
26281
18:53:32,336 --> 18:53:33,336
fries your circuit board and Fries your
26282
18:53:34,256 --> 18:53:35,256
hard drive or it can actually plant some
26283
18:53:37,144 --> 18:53:38,144
lines of code
26284
18:53:40,920 --> 18:53:41,920
Insider threats normally an employee or
26285
18:53:43,680 --> 18:53:44,680
a contractor
26286
18:53:45,000 --> 18:53:46,000
they could be under duress working for a
26287
18:53:47,336 --> 18:53:48,336
competitor or a blackmailer looking to
26288
18:53:51,000 --> 18:53:52,000
get information
26289
18:53:53,040 --> 18:53:54,040
and most security focuses on external
26290
18:53:55,976 --> 18:53:56,976
threats so it's looking at
26291
18:53:59,936 --> 18:54:00,936
incoming attacks
26292
18:54:02,216 --> 18:54:03,216
malware Trojans all that kind of stuff
26293
18:54:04,552 --> 18:54:05,552
but inside your organization obviously
26294
18:54:07,256 --> 18:54:08,256
you could have people that are posing
26295
18:54:09,120 --> 18:54:10,120
the threat
26296
18:54:10,552 --> 18:54:11,552
so people who work for your organization
26297
18:54:13,192 --> 18:54:14,192
should know your systems policies
26298
18:54:14,760 --> 18:54:15,760
procedures and weaknesses and they
26299
18:54:17,400 --> 18:54:18,400
should know how to spot somebody Who's
26300
18:54:19,144 --> 18:54:20,144
acting suspiciously or acting for
26301
18:54:21,240 --> 18:54:22,240
suspicious information
26302
18:54:23,160 --> 18:54:24,160
as you've probably seen in the movies
26303
18:54:24,784 --> 18:54:25,784
you could have what's known as a sleeper
26304
18:54:28,440 --> 18:54:29,440
so we normally uh
26305
18:54:30,832 --> 18:54:31,832
associate this with spies sleeper agents
26306
18:54:34,256 --> 18:54:35,256
let's sleep with somebody who could be
26307
18:54:35,576 --> 18:54:36,576
waiting to be activated
26308
18:54:37,976 --> 18:54:38,976
obviously they could easily go
26309
18:54:39,176 --> 18:54:40,176
undetected and they could be doing
26310
18:54:42,056 --> 18:54:43,056
um things to your network or passing
26311
18:54:43,552 --> 18:54:44,552
information for some time
26312
18:54:47,040 --> 18:54:48,040
a logic bomb is a type of malware
26313
18:54:49,856 --> 18:54:50,856
it does damage after a certain condition
26314
18:54:52,144 --> 18:54:53,144
is met so an example is
26315
18:54:54,784 --> 18:54:55,784
um the spyware or the the malware sorry
26316
18:54:57,000 --> 18:54:58,000
is on your device
26317
18:54:58,856 --> 18:54:59,856
and then when the clock ticks over to
26318
18:55:01,144 --> 18:55:02,144
the first of the first say 2019 or
26319
18:55:05,160 --> 18:55:06,160
whatever it then executes the
26320
18:55:09,832 --> 18:55:10,832
it executes the code and then does the
26321
18:55:11,872 --> 18:55:12,872
damage
26322
18:55:13,800 --> 18:55:14,800
it can be left behind after attack and
26323
18:55:15,600 --> 18:55:16,600
what it could do is destroy any evidence
26324
18:55:17,400 --> 18:55:18,400
that is taking place so it could destroy
26325
18:55:19,440 --> 18:55:20,440
whatever fires it's actually put on your
26326
18:55:21,120 --> 18:55:22,120
system making it harder for you to do a
26327
18:55:23,336 --> 18:55:24,336
forensic analysis
26328
18:55:25,440 --> 18:55:26,440
you may remember the Chernobyl virus
26329
18:55:27,480 --> 18:55:28,480
this was an example of a logic bomb
26330
18:55:30,656 --> 18:55:31,656
they wrote to the boot sector of discs
26331
18:55:33,296 --> 18:55:34,296
swipe the bias on the hard drives and
26332
18:55:35,336 --> 18:55:36,336
left the devices unusable
26333
18:55:37,976 --> 18:55:38,976
so pretty bad
26334
18:55:39,536 --> 18:55:40,536
uh Rogue access points so we're talking
26335
18:55:42,360 --> 18:55:43,360
about the um waps wireless access points
26336
18:55:45,600 --> 18:55:46,600
major concern especially in large
26337
18:55:47,640 --> 18:55:48,640
environments
26338
18:55:49,144 --> 18:55:50,144
so somebody's brought in a third-party
26339
18:55:51,240 --> 18:55:52,240
access point by Network user often this
26340
18:55:54,360 --> 18:55:55,360
can happen when somebody's complaining
26341
18:55:56,160 --> 18:55:57,160
about
26342
18:55:57,176 --> 18:55:58,176
their signals you've got you know you've
26343
18:55:59,280 --> 18:56:00,280
got bars on your device so you've got
26344
18:56:02,040 --> 18:56:03,040
one or two bars then I've seen instances
26345
18:56:05,464 --> 18:56:06,464
where people have brought in their own
26346
18:56:07,616 --> 18:56:08,616
access points and somehow managed to
26347
18:56:10,144 --> 18:56:11,144
connect to the network and they get
26348
18:56:12,600 --> 18:56:13,600
obviously a higher connection or faster
26349
18:56:16,080 --> 18:56:17,080
connection
26350
18:56:17,160 --> 18:56:18,160
so gives a network access to anybody in
26351
18:56:20,040 --> 18:56:21,040
range of the Rogue access point so this
26352
18:56:21,600 --> 18:56:22,600
is the the danger of people who uh on
26353
18:56:24,896 --> 18:56:25,896
purpose or just accidentally they don't
26354
18:56:27,000 --> 18:56:28,000
know how the technology works a lot of
26355
18:56:29,040 --> 18:56:30,040
other devices will be associating with
26356
18:56:31,016 --> 18:56:32,016
this access point here when it should
26357
18:56:32,824 --> 18:56:33,824
have actually gone off to the corporate
26358
18:56:34,320 --> 18:56:35,320
one
26359
18:56:35,872 --> 18:56:36,872
you mitigate this for regular site
26360
18:56:37,680 --> 18:56:38,680
surveys basically you're walking around
26361
18:56:39,296 --> 18:56:40,296
with um your wireless wireless device
26362
18:56:42,960 --> 18:56:43,960
checking for legitimate devices
26363
18:56:46,800 --> 18:56:47,800
uh you can force users to authenticate
26364
18:56:49,504 --> 18:56:50,504
user NATO 2.1x
26365
18:56:52,552 --> 18:56:53,552
uh also can happen if you enable Wi-Fi
26366
18:56:55,080 --> 18:56:56,080
sharing on your phone so if you're stuck
26367
18:56:58,080 --> 18:56:59,080
somewhere you've got your smartphone
26368
18:57:00,000 --> 18:57:01,000
there's a little
26369
18:57:01,744 --> 18:57:02,744
um app in there where you can let the
26370
18:57:03,480 --> 18:57:04,480
devices say for example your laptop if
26371
18:57:06,296 --> 18:57:07,296
that doesn't have a capability it can
26372
18:57:09,240 --> 18:57:10,240
actually piggyback onto your
26373
18:57:12,056 --> 18:57:13,056
um phone with a wireless signal
26374
18:57:14,400 --> 18:57:15,400
and then connect to the network so
26375
18:57:16,856 --> 18:57:17,856
you've got to be careful of that
26376
18:57:18,720 --> 18:57:19,720
Wireless evil twins this is uh configure
26377
18:57:22,192 --> 18:57:23,192
an external access point to behave as
26378
18:57:24,960 --> 18:57:25,960
The Trusted access points
26379
18:57:27,296 --> 18:57:28,296
it used the same SSID
26380
18:57:32,936 --> 18:57:33,936
and their security settings
26381
18:57:36,056 --> 18:57:37,056
so it'll all look the same
26382
18:57:38,104 --> 18:57:39,104
and the user connects you can see the
26383
18:57:40,320 --> 18:57:41,320
the legitimate one is here but the
26384
18:57:42,120 --> 18:57:43,120
signal is pretty weak the signal here is
26385
18:57:44,872 --> 18:57:45,872
much stronger so you'll more likely
26386
18:57:47,400 --> 18:57:48,400
connect to the Rogue access point
26387
18:57:49,936 --> 18:57:50,936
this device normally will have a quite a
26388
18:57:53,280 --> 18:57:54,280
strong signal on purpose so it is chosen
26389
18:57:56,760 --> 18:57:57,760
of the legitimate one
26390
18:57:58,680 --> 18:57:59,680
again this can be brought in by Network
26391
18:58:00,480 --> 18:58:01,480
users innocently or it can be done
26392
18:58:02,824 --> 18:58:03,824
maliciously
26393
18:58:03,896 --> 18:58:04,896
mitigate with https or VPN tunnels
26394
18:58:10,192 --> 18:58:11,192
while driving is just simply this
26395
18:58:12,424 --> 18:58:13,424
happened when Wireless first came out
26396
18:58:13,856 --> 18:58:14,856
and nobody had security or it was just a
26397
18:58:16,144 --> 18:58:17,144
very weak security people drove around
26398
18:58:18,720 --> 18:58:19,720
trying to find some wireless access
26399
18:58:20,280 --> 18:58:21,280
somewhere and
26400
18:58:22,616 --> 18:58:23,616
um
26401
18:58:23,160 --> 18:58:24,160
if they could see your device and
26402
18:58:24,720 --> 18:58:25,720
connect to it even when I it wasn't too
26403
18:58:27,424 --> 18:58:28,424
many years ago and my my internet went
26404
18:58:29,576 --> 18:58:30,576
down and I um I could see on my wireless
26405
18:58:34,744 --> 18:58:35,744
um if you do a wireless search you'll
26406
18:58:38,040 --> 18:58:39,040
see
26407
18:58:38,872 --> 18:58:39,872
a few padlocks
26408
18:58:40,552 --> 18:58:41,552
and then um you'd have one with a open
26409
18:58:44,336 --> 18:58:45,336
padlock and you can just you could
26410
18:58:46,552 --> 18:58:47,552
connect to that so you see it less now
26411
18:58:49,016 --> 18:58:50,016
because most of them are configured
26412
18:58:50,400 --> 18:58:51,400
quite easily for security
26413
18:58:53,824 --> 18:58:54,824
fishing email sent which is looks
26414
18:58:56,104 --> 18:58:57,104
legitimate usually appears to be from an
26415
18:58:58,616 --> 18:58:59,616
official website and it asks you to
26416
18:59:00,960 --> 18:59:01,960
click on the URL so you click here the
26417
18:59:04,552 --> 18:59:05,552
sort of things I'll see are
26418
18:59:07,320 --> 18:59:08,320
it'll say Amazon or um
26419
18:59:11,104 --> 18:59:12,104
text message
26420
18:59:13,800 --> 18:59:14,800
and even smarter people have been caught
26421
18:59:15,896 --> 18:59:16,896
out say for example if you're like me
26422
18:59:18,656 --> 18:59:19,656
maybe every three days you've got an
26423
18:59:21,120 --> 18:59:22,120
Amazon delivery coming or um or
26424
18:59:23,936 --> 18:59:24,936
something from eBay so if you're busy
26425
18:59:26,336 --> 18:59:27,336
you'll see it I think oh no I've missed
26426
18:59:28,376 --> 18:59:29,376
my Amazon delivery too late you've
26427
18:59:30,656 --> 18:59:31,656
clicked on it and um the damage has been
26428
18:59:32,576 --> 18:59:33,576
done
26429
18:59:33,536 --> 18:59:34,536
fishing can be phone based also you come
26430
18:59:36,360 --> 18:59:37,360
to this with email security systems spun
26431
18:59:38,696 --> 18:59:39,696
viruses fishing Etc
26432
18:59:41,824 --> 18:59:42,824
ransomware has really been in the news
26433
18:59:44,104 --> 18:59:45,104
lately because even the law enforcement
26434
18:59:46,800 --> 18:59:47,800
agencies have been caught it's taken out
26435
18:59:48,600 --> 18:59:49,600
large areas of um the National Health
26436
18:59:51,360 --> 18:59:52,360
Service in the UK
26437
18:59:53,040 --> 18:59:54,040
it limits all of some system access and
26438
18:59:55,920 --> 18:59:56,920
it locks your screen as it does here
26439
18:59:57,656 --> 18:59:58,656
until you've paid money to the extorters
26440
19:00:03,056 --> 19:00:04,056
offers threatens to publish your data
26441
19:00:05,336 --> 19:00:06,336
and if in the case of uh
26442
19:00:07,616 --> 19:00:08,616
I can't remember what it was some sort
26443
19:00:09,480 --> 19:00:10,480
of police department anyway but it
26444
19:00:11,280 --> 19:00:12,280
accessed all of their systems somebody
26445
19:00:12,720 --> 19:00:13,720
downloaded or somebody got an email uh
26446
19:00:16,680 --> 19:00:17,680
opened it up
26447
19:00:18,424 --> 19:00:19,424
and um they downloaded the software and
26448
19:00:21,896 --> 19:00:22,896
it spread through all the all the
26449
19:00:23,824 --> 19:00:24,824
devices
26450
19:00:25,256 --> 19:00:26,256
often uses cryptocurrencies for payment
26451
19:00:27,360 --> 19:00:28,360
so it's hard to trace the money
26452
19:00:30,240 --> 19:00:31,240
I often uses Trojans uh wannacry the uh
26453
19:00:33,896 --> 19:00:34,896
one of the latest ransomware
26454
19:00:36,056 --> 19:00:37,056
that uh malware
26455
19:00:38,040 --> 19:00:39,040
um software packages that came out
26456
19:00:40,256 --> 19:00:41,256
automatically transferred it didn't use
26457
19:00:42,176 --> 19:00:43,176
a Trojan
26458
19:00:43,856 --> 19:00:44,856
DNS poisoning we've already learned
26459
19:00:45,832 --> 19:00:46,832
about DNS this is a fake DNS cache entry
26460
19:00:50,512 --> 19:00:51,512
it cropsy data inserted into your system
26461
19:00:53,576 --> 19:00:54,576
and the name server returns a false
26462
19:00:56,872 --> 19:00:57,872
result so you'll do a DNS lookup it goes
26463
19:00:59,464 --> 19:01:00,464
to your DNS server but for whatever
26464
19:01:01,376 --> 19:01:02,376
reason this attacker has somehow
26465
19:01:03,536 --> 19:01:04,536
injected this fake entry and instead of
26466
19:01:05,872 --> 19:01:06,872
going off to the real server here it
26467
19:01:08,336 --> 19:01:09,336
queries the fake one and it just for all
26468
19:01:11,280 --> 19:01:12,280
intents and purposes to you looks like
26469
19:01:13,680 --> 19:01:14,680
you're actually on the correct site
26470
19:01:16,800 --> 19:01:17,800
obviously then it'll try and get
26471
19:01:18,424 --> 19:01:19,424
passwords usernames or credit card
26472
19:01:20,280 --> 19:01:21,280
information and again this false entry
26473
19:01:23,160 --> 19:01:24,160
here if you've got a DNS server it can
26474
19:01:25,440 --> 19:01:26,440
actually propagate within your depending
26475
19:01:28,144 --> 19:01:29,144
on the authority of This Server it'll
26476
19:01:30,000 --> 19:01:31,000
propagate to other servers
26477
19:01:33,120 --> 19:01:34,120
up poisoning
26478
19:01:36,000 --> 19:01:37,000
requires the attacker to have access to
26479
19:01:38,824 --> 19:01:39,824
the victim's local area network again
26480
19:01:40,616 --> 19:01:41,616
this could be a contractor or somebody
26481
19:01:43,080 --> 19:01:44,080
who's managed to get in somehow it
26482
19:01:46,496 --> 19:01:47,496
provides a host of the wrong Mac address
26483
19:01:47,872 --> 19:01:48,872
for hosts the host IP address so
26484
19:01:52,016 --> 19:01:53,016
um if we go down here this host is
26485
19:01:53,640 --> 19:01:54,640
looking for the you can't say it can't
26486
19:01:55,856 --> 19:01:56,856
encapsulate the packet as we already
26487
19:01:57,536 --> 19:01:58,536
know until it knows the MAC address so
26488
19:02:01,744 --> 19:02:02,744
there's a field here for layer three and
26489
19:02:04,800 --> 19:02:05,800
then but for Layer Two in order to send
26490
19:02:07,464 --> 19:02:08,464
the packet out it needs to know the Mac
26491
19:02:11,160 --> 19:02:12,160
and if it's got a the false entry here
26492
19:02:14,216 --> 19:02:15,216
from the attacker then it will send it
26493
19:02:16,144 --> 19:02:17,144
to the wrong host it'll send it to here
26494
19:02:18,896 --> 19:02:19,896
instead of here or vice versa
26495
19:02:22,016 --> 19:02:23,016
you combat this with Dynamic harp
26496
19:02:24,832 --> 19:02:25,832
inspection which is you will enable this
26497
19:02:27,240 --> 19:02:28,240
on switches
26498
19:02:28,976 --> 19:02:29,976
our and DHCP snooping
26499
19:02:33,296 --> 19:02:34,296
there's a lot of different type of
26500
19:02:34,680 --> 19:02:35,680
spoofing when it comes to hacking this
26501
19:02:37,616 --> 19:02:38,616
is pretending to be someone or something
26502
19:02:39,424 --> 19:02:40,424
you want
26503
19:02:40,920 --> 19:02:41,920
and one type of spoofing is DHCP
26504
19:02:43,080 --> 19:02:44,080
spoofing the idea is the software
26505
19:02:46,144 --> 19:02:47,144
exhausts the pool of addresses so you'll
26506
19:02:48,784 --> 19:02:49,784
have a pool of say
26507
19:02:50,576 --> 19:02:51,576
10 000 addresses and it will spoof keep
26508
19:02:54,176 --> 19:02:55,176
requesting the addresses until
26509
19:02:57,000 --> 19:02:58,000
eventually there's zero left at which
26510
19:02:59,872 --> 19:03:00,872
point in the DHCP server can't allocate
26511
19:03:02,824 --> 19:03:03,824
information and then hosts on your
26512
19:03:04,192 --> 19:03:05,192
network can't join the network
26513
19:03:07,016 --> 19:03:08,016
uh the Mac impersonates house or device
26514
19:03:10,936 --> 19:03:11,936
on Two Hosts on one switch Port so this
26515
19:03:15,000 --> 19:03:16,000
is actually poisoning it looks like the
26516
19:03:17,280 --> 19:03:18,280
port on the switch here it should have
26517
19:03:19,920 --> 19:03:20,920
one Mac address per port
26518
19:03:22,376 --> 19:03:23,376
but
26519
19:03:23,576 --> 19:03:24,576
it's got two associated with the uh Port
26520
19:03:27,000 --> 19:03:28,000
which um
26521
19:03:28,856 --> 19:03:29,856
it can it can happen if you've got a um
26522
19:03:31,800 --> 19:03:32,800
Hub plugged in but it would you would
26523
19:03:33,896 --> 19:03:34,896
normally have this on your network
26524
19:03:36,360 --> 19:03:37,360
however the ARP Source the MAC address
26525
19:03:38,160 --> 19:03:39,160
is disguised and the arc cache is
26526
19:03:40,016 --> 19:03:41,016
poisoned
26527
19:03:42,616 --> 19:03:43,616
de-authentication this is used on Wi-Fi
26528
19:03:45,296 --> 19:03:46,296
networks this is more of a pain than
26529
19:03:47,104 --> 19:03:48,104
anything it sends a de-authentication
26530
19:03:49,744 --> 19:03:50,744
frame to the host to end the session the
26531
19:03:53,160 --> 19:03:54,160
attackers boosts the victim's Mac
26532
19:03:54,480 --> 19:03:55,480
address which you could attain by
26533
19:03:56,104 --> 19:03:57,104
sniffing while a sniffing now there's no
26534
19:03:58,552 --> 19:03:59,552
need for encryption so even though
26535
19:04:01,144 --> 19:04:02,144
you've got an encrypted uh connection
26536
19:04:05,160 --> 19:04:06,160
so or your device or all your traffic is
26537
19:04:07,976 --> 19:04:08,976
encrypted the de-authentication frame
26538
19:04:10,552 --> 19:04:11,552
doesn't have to be
26539
19:04:12,784 --> 19:04:13,784
so whatever that frame will say
26540
19:04:17,464 --> 19:04:18,464
whatever whatever it says in the frame
26541
19:04:19,080 --> 19:04:20,080
to tell it to terminate the session that
26542
19:04:21,056 --> 19:04:22,056
doesn't have to be so it's a floor in
26543
19:04:23,464 --> 19:04:24,464
the technology
26544
19:04:25,744 --> 19:04:26,744
brute force uh this is a type of
26545
19:04:28,144 --> 19:04:29,144
password attack the other type is a
26546
19:04:29,760 --> 19:04:30,760
dictionary attack so what the Brute
26547
19:04:33,056 --> 19:04:34,056
Force attack does it just keeps guessing
26548
19:04:34,920 --> 19:04:35,920
over and over
26549
19:04:36,784 --> 19:04:37,784
to try and find the password
26550
19:04:39,176 --> 19:04:40,176
typically the username would have been
26551
19:04:40,856 --> 19:04:41,856
installed and
26552
19:04:43,144 --> 19:04:44,144
um yeah you'll have a hashed version of
26553
19:04:44,872 --> 19:04:45,872
the password this is what it's trying to
26554
19:04:46,496 --> 19:04:47,496
guess
26555
19:04:47,872 --> 19:04:48,872
the same hashing algorithm is used for
26556
19:04:50,160 --> 19:04:51,160
example md5 is used
26557
19:04:53,160 --> 19:04:54,160
and it will use this to try and send
26558
19:04:55,440 --> 19:04:56,440
hash values
26559
19:04:56,936 --> 19:04:57,936
you'll combat it using Advanced
26560
19:04:58,800 --> 19:04:59,800
algorithms so you'd have like millions
26561
19:05:01,256 --> 19:05:02,256
or billions of combinations
26562
19:05:03,960 --> 19:05:04,960
um for example RSA or public key
26563
19:05:05,872 --> 19:05:06,872
encryption
26564
19:05:09,536 --> 19:05:10,536
VLAN hop in uh host typically require a
26565
19:05:12,600 --> 19:05:13,600
layer 3 device to reach under the VLAN
26566
19:05:14,872 --> 19:05:15,872
and if I've got a picture of this
26567
19:05:16,976 --> 19:05:17,976
actually but we've seen before if you've
26568
19:05:19,616 --> 19:05:20,616
got a hosts
26569
19:05:21,424 --> 19:05:22,424
in this VLAN
26570
19:05:23,336 --> 19:05:24,336
and they will connect to a switch and
26571
19:05:25,744 --> 19:05:26,744
then hosts in this VLAN
26572
19:05:28,976 --> 19:05:29,976
so VLAN 10 VLAN 20 and they'll be
26573
19:05:32,104 --> 19:05:33,104
they'll have different IP addresses but
26574
19:05:34,552 --> 19:05:35,552
uh these do these devices can't connect
26575
19:05:36,720 --> 19:05:37,720
to one another unless the switch is
26576
19:05:39,000 --> 19:05:40,000
connected to a layer 3 device now this
26577
19:05:41,936 --> 19:05:42,936
can actually be built into the switch it
26578
19:05:43,920 --> 19:05:44,920
could be a multi-layer switch but it has
26579
19:05:45,960 --> 19:05:46,960
to have this layer 3 capability
26580
19:05:48,656 --> 19:05:49,656
well VLAN hopping the attacker attempts
26581
19:05:50,872 --> 19:05:51,872
to bypass the layer 3 device to com
26582
19:05:52,920 --> 19:05:53,920
compromise another device and you could
26583
19:05:55,440 --> 19:05:56,440
have all your security
26584
19:05:57,656 --> 19:05:58,656
or some of your security built into this
26585
19:06:00,424 --> 19:06:01,424
layer 3 device
26586
19:06:02,464 --> 19:06:03,464
here it's done by a switch spoofing or
26587
19:06:05,216 --> 19:06:06,216
double tagging
26588
19:06:07,680 --> 19:06:08,680
so switch spoofing the device
26589
19:06:09,176 --> 19:06:10,176
impersonates a switch whatever this
26590
19:06:12,000 --> 19:06:13,000
Rogue device is it's pretending to be a
26591
19:06:14,336 --> 19:06:15,336
switch so probably we'll need a trunk
26592
19:06:17,040 --> 19:06:18,040
link here
26593
19:06:19,552 --> 19:06:20,552
you combat it by disabling trunking
26594
19:06:21,720 --> 19:06:22,720
where not required
26595
19:06:24,896 --> 19:06:25,896
to say this is your frame here and you
26596
19:06:28,080 --> 19:06:29,080
would have your VLAN
26597
19:06:31,016 --> 19:06:32,016
uh 10 here and say 20 here well normally
26598
19:06:36,056 --> 19:06:37,056
when the frame reaches the destination
26599
19:06:38,464 --> 19:06:39,464
the VLAN tag is removed because the
26600
19:06:40,800 --> 19:06:41,800
hosts don't really care that they're in
26601
19:06:42,120 --> 19:06:43,120
a VLAN but what they can do with VLAN
26602
19:06:44,216 --> 19:06:45,216
hopping is they can add an extra one
26603
19:06:47,936 --> 19:06:48,936
um here in order to gain access to a
26604
19:06:50,512 --> 19:06:51,512
VLAN when this device might be over here
26605
19:06:53,104 --> 19:06:54,104
on VLAN 20.
26606
19:06:55,920 --> 19:06:56,920
so that's double tagging
26607
19:06:58,680 --> 19:06:59,680
combat by using a dedicated VLAN for all
26608
19:07:01,192 --> 19:07:02,192
trunk links
26609
19:07:02,696 --> 19:07:03,696
so your trunk link between this switch
26610
19:07:05,576 --> 19:07:06,576
here
26611
19:07:07,016 --> 19:07:08,016
is switch here this switch here you've
26612
19:07:10,320 --> 19:07:11,320
got a special VLAN only used between
26613
19:07:13,976 --> 19:07:14,976
these trunk links so save VLAN 101 102
26614
19:07:19,872 --> 19:07:20,872
103. these these numbers aren't used
26615
19:07:22,616 --> 19:07:23,616
anywhere else on the network they're
26616
19:07:24,296 --> 19:07:25,296
just used for the trunk links
26617
19:07:29,464 --> 19:07:30,464
uh this is just a diagram showing you um
26618
19:07:32,760 --> 19:07:33,760
the double tag frame here so the switch
26619
19:07:35,280 --> 19:07:36,280
arm removes the first tagging forwards
26620
19:07:37,080 --> 19:07:38,080
to switch to and this time
26621
19:07:39,424 --> 19:07:40,424
the tag is still attached to it
26622
19:07:45,056 --> 19:07:46,056
man in the middle attack uh convinces
26623
19:07:47,280 --> 19:07:48,280
the sender and receiver that the
26624
19:07:48,832 --> 19:07:49,832
computer in the middle is the actual
26625
19:07:50,216 --> 19:07:51,216
host so this host here thinks it says
26626
19:07:52,376 --> 19:07:53,376
speaking to the server the server thinks
26627
19:07:54,424 --> 19:07:55,424
he's speaking to this host over here
26628
19:07:55,856 --> 19:07:56,856
really it's going between this
26629
19:07:58,376 --> 19:07:59,376
intermediary device here which is the
26630
19:08:00,120 --> 19:08:01,120
attacker
26631
19:08:02,104 --> 19:08:03,104
you normally accompany this with DNS or
26632
19:08:04,440 --> 19:08:05,440
ARP spoofing so there'd be an ARP cache
26633
19:08:06,536 --> 19:08:07,536
here
26634
19:08:09,600 --> 19:08:10,600
and here and it would say the back
26635
19:08:12,896 --> 19:08:13,896
address for this particular host but
26636
19:08:15,424 --> 19:08:16,424
really it's injected a false Mac address
26637
19:08:17,040 --> 19:08:18,040
here
26638
19:08:18,536 --> 19:08:19,536
and it and the messages are actually
26639
19:08:20,576 --> 19:08:21,576
sent and received
26640
19:08:22,616 --> 19:08:23,616
so there's acknowledgment it sends and
26641
19:08:25,440 --> 19:08:26,440
then this device here will send out an
26642
19:08:27,176 --> 19:08:28,176
acknowledgment but really it's going
26643
19:08:28,616 --> 19:08:29,616
through the middle here
26644
19:08:30,240 --> 19:08:31,240
type of spoofing attack
26645
19:08:33,120 --> 19:08:34,120
I've renderability scanning
26646
19:08:35,336 --> 19:08:36,336
um
26647
19:08:36,360 --> 19:08:37,360
this should have appeared in a moment
26648
19:08:38,280 --> 19:08:39,280
sorry it probes the host in order to
26649
19:08:40,192 --> 19:08:41,192
find an explode exploitable service or
26650
19:08:43,256 --> 19:08:44,256
process so you've got your server here
26651
19:08:45,720 --> 19:08:46,720
and obviously there's ports permitted or
26652
19:08:49,376 --> 19:08:50,376
denied but it will keep probing until it
26653
19:08:52,552 --> 19:08:53,552
finally finds one that's open and then
26654
19:08:55,144 --> 19:08:56,144
it will try and do some damage
26655
19:08:57,656 --> 19:08:58,656
there's a whole bunch of tools if you do
26656
19:08:59,512 --> 19:09:00,512
an ethical hacking course for example
26657
19:09:01,256 --> 19:09:02,256
you can download there's a ton of free
26658
19:09:04,320 --> 19:09:05,320
tools that um the idea is you're trying
26659
19:09:08,280 --> 19:09:09,280
to learn how to protect your system but
26660
19:09:10,144 --> 19:09:11,144
they're obviously available for use by
26661
19:09:11,872 --> 19:09:12,872
hackers
26662
19:09:13,376 --> 19:09:14,376
now say there's a particular Port open
26663
19:09:15,784 --> 19:09:16,784
or a service so
26664
19:09:18,424 --> 19:09:19,424
um like an instant messenger Port has
26665
19:09:20,216 --> 19:09:21,216
been left open
26666
19:09:21,656 --> 19:09:22,656
this will then tell the attacker the
26667
19:09:23,760 --> 19:09:24,760
hacker what type of attack will work
26668
19:09:25,504 --> 19:09:26,504
best on this particular Port so it may
26669
19:09:27,784 --> 19:09:28,784
not use that specific pool but it may
26670
19:09:29,576 --> 19:09:30,576
then be able to Target a vulnerability
26671
19:09:31,680 --> 19:09:32,680
in the application
26672
19:09:33,360 --> 19:09:34,360
one of the tools you could use is a nmap
26673
19:09:36,720 --> 19:09:37,720
you obviously counteract all of this by
26674
19:09:38,512 --> 19:09:39,512
doing some penetration testing or paying
26675
19:09:40,496 --> 19:09:41,496
for it
26676
19:09:41,640 --> 19:09:42,640
and here's a result from the nmap tool
26677
19:09:45,120 --> 19:09:46,120
here
26678
19:09:47,216 --> 19:09:48,216
and then it's giving you your your
26679
19:09:49,144 --> 19:09:50,144
outputs you'll learn more if you do
26680
19:09:50,936 --> 19:09:51,936
penetration testing which isn't really
26681
19:09:52,680 --> 19:09:53,680
covered in the syllabus
26682
19:09:55,144 --> 19:09:56,144
all right so we've covered a lot of
26683
19:09:57,000 --> 19:09:58,000
stuff social engineering Insider threats
26684
19:10:00,120 --> 19:10:01,120
logic bombs the Rogue access point that
26685
19:10:02,696 --> 19:10:03,696
somebody brings in evil twin driving
26686
19:10:05,400 --> 19:10:06,400
around looking for a free wireless
26687
19:10:07,256 --> 19:10:08,256
fishing
26688
19:10:09,896 --> 19:10:10,896
uh ransomware poisoning the DNS entries
26689
19:10:13,440 --> 19:10:14,440
the ARP cache spoofing is pretending to
26690
19:10:16,616 --> 19:10:17,616
be something or someone you're not
26691
19:10:19,080 --> 19:10:20,080
D authentication the frames got
26692
19:10:22,800 --> 19:10:23,800
um it can be in clear text Brute Force
26693
19:10:25,800 --> 19:10:26,800
attacks VLAN hopping man in the middle
26694
19:10:28,552 --> 19:10:29,552
and then exploits versus vulnerabilities
26695
19:10:30,960 --> 19:10:31,960
that's all for now thanks for listening
26696
19:10:36,600 --> 19:10:37,600
[Music]
26697
19:10:45,144 --> 19:10:46,144
thank you
26698
19:10:56,280 --> 19:10:57,280
network security threat mitigation and
26699
19:11:00,176 --> 19:11:01,176
user education
26700
19:11:02,936 --> 19:11:03,936
we've now talked about a lot of the
26701
19:11:04,856 --> 19:11:05,856
different types of attacks and security
26702
19:11:06,832 --> 19:11:07,832
threats that you encounter in today's
26703
19:11:09,296 --> 19:11:10,296
world when it comes to your network and
26704
19:11:11,640 --> 19:11:12,640
we've talked about ways to protect from
26705
19:11:14,512 --> 19:11:15,512
these threats from attacks to antivirus
26706
19:11:18,424 --> 19:11:19,424
software and so on but let's talk a
26707
19:11:20,872 --> 19:11:21,872
little further about how we can mitigate
26708
19:11:23,336 --> 19:11:24,336
these threats and if that word is new to
26709
19:11:26,280 --> 19:11:27,280
you the first thing we're going to talk
26710
19:11:27,720 --> 19:11:28,720
about is what threat mitigation means
26711
19:11:31,552 --> 19:11:32,552
we're then going to identify some of the
26712
19:11:33,600 --> 19:11:34,600
steps in a good protection strategy
26713
19:11:36,424 --> 19:11:37,424
these include developing strong security
26714
19:11:40,256 --> 19:11:41,256
policies monitoring the threats on your
26715
19:11:43,440 --> 19:11:44,440
network something that we've talked
26716
19:11:44,576 --> 19:11:45,576
about in the past a hugely important one
26717
19:11:47,040 --> 19:11:48,040
educating users since almost all the
26718
19:11:50,280 --> 19:11:51,280
threats we've talked about in some way
26719
19:11:52,616 --> 19:11:53,616
shape or form have to do with what we
26720
19:11:55,080 --> 19:11:56,080
call social engineering
26721
19:11:57,000 --> 19:11:58,000
in other words getting someone to do
26722
19:11:58,856 --> 19:11:59,856
what you want them to do for instance
26723
19:12:00,424 --> 19:12:01,424
give them your password
26724
19:12:02,216 --> 19:12:03,216
automating scanning and updates both
26725
19:12:05,512 --> 19:12:06,512
from uh updates of the operating system
26726
19:12:07,744 --> 19:12:08,744
and from the virus scan program and
26727
19:12:10,376 --> 19:12:11,376
patches and updates for our operating
26728
19:12:13,144 --> 19:12:14,144
systems and our software
26729
19:12:15,832 --> 19:12:16,832
so what is mitigation one of the only
26730
19:12:19,744 --> 19:12:20,744
ways that a network can stand a chance
26731
19:12:22,144 --> 19:12:23,144
against attacks is to do something
26732
19:12:24,480 --> 19:12:25,480
before the attack is made isn't it said
26733
19:12:27,536 --> 19:12:28,536
that an ounce of prevention is worth a
26734
19:12:29,336 --> 19:12:30,336
pound of cure well this means more than
26735
19:12:31,616 --> 19:12:32,616
just having anti-virus and firewalls in
26736
19:12:34,080 --> 19:12:35,080
place those things are great but they
26737
19:12:36,056 --> 19:12:37,056
can only stop an attack that's already
26738
19:12:38,160 --> 19:12:39,160
being made really the best way to
26739
19:12:40,320 --> 19:12:41,320
protect a network is to set up
26740
19:12:42,480 --> 19:12:43,480
prevention measures before an attack can
26741
19:12:45,240 --> 19:12:46,240
happen
26742
19:12:46,320 --> 19:12:47,320
the idiom of an ounce prevention is
26743
19:12:49,016 --> 19:12:50,016
worth a pound of cure means that you
26744
19:12:51,056 --> 19:12:52,056
save a huge amount of trouble by
26745
19:12:53,760 --> 19:12:54,760
preventing the trouble from even
26746
19:12:55,320 --> 19:12:56,320
happening so one of the best ways to do
26747
19:12:57,832 --> 19:12:58,832
that is to mitigate the threats that are
26748
19:13:00,360 --> 19:13:01,360
made on your network mitigation is a
26749
19:13:03,296 --> 19:13:04,296
word that doesn't just apply to
26750
19:13:04,376 --> 19:13:05,376
networking but in this case we're
26751
19:13:06,424 --> 19:13:07,424
talking about it in the sense of
26752
19:13:07,616 --> 19:13:08,616
lessening of a chance of an attack by
26753
19:13:10,496 --> 19:13:11,496
using mitigation you're taking measures
26754
19:13:12,480 --> 19:13:13,480
to reduce the frequency of attacks the
26755
19:13:15,360 --> 19:13:16,360
size of those attacks when and if they
26756
19:13:17,216 --> 19:13:18,216
take place how severely most importantly
26757
19:13:20,464 --> 19:13:21,464
they're going to impact your network we
26758
19:13:22,496 --> 19:13:23,496
need to have a strategy in place in
26759
19:13:24,536 --> 19:13:25,536
order to mitigate threats and make life
26760
19:13:27,240 --> 19:13:28,240
on the network easier
26761
19:13:29,824 --> 19:13:30,824
so step one of the mitigation strategy
26762
19:13:33,296 --> 19:13:34,296
needs to be to set up rules and policies
26763
19:13:35,936 --> 19:13:36,936
within a network users are set up by the
26764
19:13:38,576 --> 19:13:39,576
administrator and need to be agreed upon
26765
19:13:40,496 --> 19:13:41,496
by all the high up people on the network
26766
19:13:42,504 --> 19:13:43,504
and all the high up people in your
26767
19:13:45,000 --> 19:13:46,000
corporation they then need to be told to
26768
19:13:48,424 --> 19:13:49,424
all of the users these rules should be
26769
19:13:50,824 --> 19:13:51,824
standard throughout the network with
26770
19:13:52,800 --> 19:13:53,800
very few exceptions because these
26771
19:13:54,832 --> 19:13:55,832
exceptions easily lead to a breach in
26772
19:13:56,824 --> 19:13:57,824
security
26773
19:13:57,784 --> 19:13:58,784
one of the rules that needs to be set up
26774
19:13:59,760 --> 19:14:00,760
for instance is what can users download
26775
19:14:02,104 --> 19:14:03,104
such as applications can they download
26776
19:14:04,744 --> 19:14:05,744
stuff like browsers well some of them
26777
19:14:07,080 --> 19:14:08,080
are trustable but are we going to trust
26778
19:14:09,120 --> 19:14:10,120
people on our Network to choose the
26779
19:14:11,464 --> 19:14:12,464
browsers that are actually worth
26780
19:14:13,376 --> 19:14:14,376
trusting
26781
19:14:14,464 --> 19:14:15,464
the administrator needs to be wary of
26782
19:14:16,616 --> 19:14:17,616
just about any program that a user could
26783
19:14:18,600 --> 19:14:19,600
download and as we learned in the last
26784
19:14:20,640 --> 19:14:21,640
module viruses can hide within programs
26785
19:14:23,512 --> 19:14:24,512
they don't just attack out of nowhere a
26786
19:14:26,104 --> 19:14:27,104
user on your network could easily
26787
19:14:27,360 --> 19:14:28,360
download a virus without even knowing it
26788
19:14:28,856 --> 19:14:29,856
and then they end up infecting not just
26789
19:14:30,720 --> 19:14:31,720
their computer but the entire network so
26790
19:14:33,360 --> 19:14:34,360
a rule needs to be put in place that
26791
19:14:34,920 --> 19:14:35,920
says whether or not downloading of
26792
19:14:36,480 --> 19:14:37,480
applications is allowed and if it is
26793
19:14:38,696 --> 19:14:39,696
from what sources you may even want to
26794
19:14:41,040 --> 19:14:42,040
limit the fact that people can download
26795
19:14:43,144 --> 19:14:44,144
by shutting off their user rights to
26796
19:14:45,784 --> 19:14:46,784
download or to install programs on their
26797
19:14:48,176 --> 19:14:49,176
network if they can't install anything
26798
19:14:50,040 --> 19:14:51,040
they can install a virus another major
26799
19:14:52,616 --> 19:14:53,616
Rule and this is really important is are
26800
19:14:54,536 --> 19:14:55,536
they allowed to use outside storage
26801
19:14:56,160 --> 19:14:57,160
devices such as uh removable hard drives
26802
19:15:00,960 --> 19:15:01,960
thumb drives flash drives and storage
26803
19:15:04,256 --> 19:15:05,256
CDs any one of these media storage
26804
19:15:07,680 --> 19:15:08,680
devices can contain malware one of the
26805
19:15:11,104 --> 19:15:12,104
uh classic examples is
26806
19:15:14,824 --> 19:15:15,824
someone leaves flash drives in the
26807
19:15:17,216 --> 19:15:18,216
parking lot when you find the flash
26808
19:15:19,616 --> 19:15:20,616
drive what's the first thing you do oh
26809
19:15:21,000 --> 19:15:22,000
you say it's a brand new flash drive I'm
26810
19:15:22,440 --> 19:15:23,440
going to put it in my computer I want to
26811
19:15:24,296 --> 19:15:25,296
test it out see what's on there see if I
26812
19:15:26,040 --> 19:15:27,040
can find the owner well the minute they
26813
19:15:28,080 --> 19:15:29,080
do that they've just infected your
26814
19:15:29,872 --> 19:15:30,872
system and your network with a virus so
26815
19:15:34,440 --> 19:15:35,440
we need to make sure that even though
26816
19:15:36,536 --> 19:15:37,536
the person might not be
26817
19:15:38,216 --> 19:15:39,216
trying or mean to infect the network
26818
19:15:40,496 --> 19:15:41,496
they could do it simply because they
26819
19:15:42,536 --> 19:15:43,536
don't understand the risks that are
26820
19:15:44,336 --> 19:15:45,336
associated with flash drives and outside
26821
19:15:46,552 --> 19:15:47,552
storage media they might also be
26822
19:15:48,536 --> 19:15:49,536
bringing stuff from their home computer
26823
19:15:49,856 --> 19:15:50,856
which very well could have a virus on it
26824
19:15:52,552 --> 19:15:53,552
so storage devices could contain malware
26825
19:15:55,680 --> 19:15:56,680
without the user even knowing it and
26826
19:15:57,536 --> 19:15:58,536
this isn't something you want to risk so
26827
19:15:59,336 --> 19:16:00,336
a policy is really important
26828
19:16:01,376 --> 19:16:02,376
other things such as this would include
26829
19:16:03,600 --> 19:16:04,600
stuff like tailgating when someone logs
26830
19:16:07,320 --> 19:16:08,320
in
26831
19:16:08,872 --> 19:16:09,872
uh swipes their card to get into a
26832
19:16:11,640 --> 19:16:12,640
building in the morning if they open the
26833
19:16:13,320 --> 19:16:14,320
door for someone else well now that
26834
19:16:15,536 --> 19:16:16,536
person just got in without being audited
26835
19:16:17,640 --> 19:16:18,640
we didn't have they didn't have to swipe
26836
19:16:19,144 --> 19:16:20,144
their card so that's a pretty major
26837
19:16:21,120 --> 19:16:22,120
concern when it comes to security
26838
19:16:23,480 --> 19:16:24,480
another one uh is something like
26839
19:16:26,760 --> 19:16:27,760
shoulder surfing or giving out your
26840
19:16:28,440 --> 19:16:29,440
password we need to make sure the
26841
19:16:30,296 --> 19:16:31,296
policies of how passwords are reset when
26842
19:16:32,872 --> 19:16:33,872
they're reset and who you can give them
26843
19:16:34,552 --> 19:16:35,552
to is fairly important if I give my
26844
19:16:37,376 --> 19:16:38,376
password to my wife and suddenly my wife
26845
19:16:39,424 --> 19:16:40,424
becomes my ex-wife she could do some
26846
19:16:41,640 --> 19:16:42,640
major damage to me and to my company by
26847
19:16:44,512 --> 19:16:45,512
using that password to get access to
26848
19:16:46,856 --> 19:16:47,856
private information
26849
19:16:49,616 --> 19:16:50,616
so step two is a mitigation strategy
26850
19:16:53,536 --> 19:16:54,536
which is to constantly monitor virus
26851
19:16:56,872 --> 19:16:57,872
threats as you might already know
26852
19:16:58,800 --> 19:16:59,800
attackers and computer hackers are very
26853
19:17:01,376 --> 19:17:02,376
well educated when it comes to getting
26854
19:17:03,832 --> 19:17:04,832
around security systems This Is How They
26855
19:17:06,960 --> 19:17:07,960
infect networks and when their attacks
26856
19:17:09,240 --> 19:17:10,240
are blocked most of them just update the
26857
19:17:11,280 --> 19:17:12,280
attack and try a new version they don't
26858
19:17:13,080 --> 19:17:14,080
just stop so this is why the
26859
19:17:14,760 --> 19:17:15,760
administrator needs to be as on top of
26860
19:17:16,920 --> 19:17:17,920
the virus versions and attackers and the
26861
19:17:19,320 --> 19:17:20,320
threats that are out there it's up to
26862
19:17:21,120 --> 19:17:22,120
the administrator to make sure that
26863
19:17:22,680 --> 19:17:23,680
they're up to date and research is being
26864
19:17:24,656 --> 19:17:25,656
done and they're knowledgeable at the
26865
19:17:26,216 --> 19:17:27,216
newest attacks that could be coming to
26866
19:17:27,896 --> 19:17:28,896
their Network again it's no one else
26867
19:17:30,056 --> 19:17:31,056
that's going to get blamed except for
26868
19:17:31,616 --> 19:17:32,616
the administrator when someone hacks to
26869
19:17:33,360 --> 19:17:34,360
the network so not only do we need to
26870
19:17:35,216 --> 19:17:36,216
monitor our Network we need to monitor
26871
19:17:37,504 --> 19:17:38,504
the threats that are out there and this
26872
19:17:40,256 --> 19:17:41,256
really involves doing research on what
26873
19:17:42,784 --> 19:17:43,784
the latest and greatest techniques are
26874
19:17:44,696 --> 19:17:45,696
to hack into a network
26875
19:17:47,040 --> 19:17:48,040
step three is user education which is
26876
19:17:49,616 --> 19:17:50,616
really I think the most important step
26877
19:17:52,696 --> 19:17:53,696
that we have out there it's critical to
26878
19:17:55,680 --> 19:17:56,680
have Network users educated in this
26879
19:17:57,656 --> 19:17:58,656
field so that they know exactly what
26880
19:18:00,056 --> 19:18:01,056
sort of threats are out there and what
26881
19:18:01,976 --> 19:18:02,976
safety habits are there as well there's
26882
19:18:04,376 --> 19:18:05,376
some safety habits that are obvious like
26883
19:18:06,424 --> 19:18:07,424
locking a device and keeping your
26884
19:18:08,040 --> 19:18:09,040
password secure but there are other
26885
19:18:10,016 --> 19:18:11,016
security measures and knowledge that's
26886
19:18:12,176 --> 19:18:13,176
less obvious but just as important
26887
19:18:14,104 --> 19:18:15,104
Network users need to be knowledgeable
26888
19:18:16,016 --> 19:18:17,016
on how to protect themselves from
26889
19:18:17,400 --> 19:18:18,400
viruses and how to recognize them so
26890
19:18:19,680 --> 19:18:20,680
they don't just click on something when
26891
19:18:21,480 --> 19:18:22,480
it pops up on their browser first they
26892
19:18:24,120 --> 19:18:25,120
personally need to back up their
26893
19:18:25,744 --> 19:18:26,744
important data because in the event of
26894
19:18:27,896 --> 19:18:28,896
an attack perhaps are
26895
19:18:30,424 --> 19:18:31,424
major system goes down alternatively
26896
19:18:33,896 --> 19:18:34,896
they need to know that they should be
26897
19:18:37,552 --> 19:18:38,552
um backing up their data to perhaps a
26898
19:18:40,920 --> 19:18:41,920
central location or they need to be
26899
19:18:42,480 --> 19:18:43,480
taught where to back up their data for
26900
19:18:44,696 --> 19:18:45,696
instance to the network share and not to
26901
19:18:46,976 --> 19:18:47,976
removable hard drive or not on their
26902
19:18:48,656 --> 19:18:49,656
desktop because if they back it up to
26903
19:18:51,000 --> 19:18:52,000
their desktop then what happens when
26904
19:18:52,552 --> 19:18:53,552
their computer gets broken now they've
26905
19:18:54,240 --> 19:18:55,240
lost all the work they didn't back up
26906
19:18:56,720 --> 19:18:57,720
automatically to the server they also
26907
19:19:00,360 --> 19:19:01,360
need to be diligent about web browsing
26908
19:19:01,920 --> 19:19:02,920
what they download what they click and
26909
19:19:03,832 --> 19:19:04,832
so on if they're administrator is going
26910
19:19:06,176 --> 19:19:07,176
to allow them to download programs they
26911
19:19:07,680 --> 19:19:08,680
need to be careful about where they
26912
19:19:08,872 --> 19:19:09,872
downloaded them from again we always
26913
19:19:11,040 --> 19:19:12,040
have this
26914
19:19:13,080 --> 19:19:14,080
interval between responsibility
26915
19:19:18,120 --> 19:19:19,120
and power the more powerful you are the
26916
19:19:20,640 --> 19:19:21,640
more responsible you have to be if I can
26917
19:19:23,464 --> 19:19:24,464
install things on my computer that also
26918
19:19:25,080 --> 19:19:26,080
means a hacker could use my information
26919
19:19:26,576 --> 19:19:27,576
to install something on the computer as
26920
19:19:28,800 --> 19:19:29,800
well and finally if a if they download a
26921
19:19:31,680 --> 19:19:32,680
program that seems illegitimate or they
26922
19:19:34,016 --> 19:19:35,016
think they've been attacked they need to
26923
19:19:36,296 --> 19:19:37,296
be able to spot the issue and report it
26924
19:19:38,336 --> 19:19:39,336
to the administrator before the risky
26925
19:19:40,320 --> 19:19:41,320
program has a chance to damage sometimes
26926
19:19:43,080 --> 19:19:44,080
they don't want to say anything because
26927
19:19:44,512 --> 19:19:45,512
they don't want to get in trouble but if
26928
19:19:46,192 --> 19:19:47,192
they had said something earlier we could
26929
19:19:47,760 --> 19:19:48,760
have prevented more damage it's really
26930
19:19:50,160 --> 19:19:51,160
important for them to know when they are
26931
19:19:52,552 --> 19:19:53,552
being deceived by something and when
26932
19:19:54,240 --> 19:19:55,240
something is legitimate so I see this
26933
19:19:56,936 --> 19:19:57,936
all the time people send up these emails
26934
19:19:58,440 --> 19:19:59,440
saying beware of this and an easy Google
26935
19:20:01,144 --> 19:20:02,144
search would show that the thing that
26936
19:20:02,824 --> 19:20:03,824
they're actually being aware of isn't
26937
19:20:04,856 --> 19:20:05,856
real it's something fake and they've
26938
19:20:07,376 --> 19:20:08,376
spent time and energy everyone's time
26939
19:20:09,000 --> 19:20:10,000
and energy getting worried about
26940
19:20:10,192 --> 19:20:11,192
something that actually is not going to
26941
19:20:11,696 --> 19:20:12,696
affect them on the other hand they don't
26942
19:20:13,920 --> 19:20:14,920
seem to recognize when someone's account
26943
19:20:16,320 --> 19:20:17,320
has been hacked and is asking for money
26944
19:20:18,056 --> 19:20:19,056
money when that person would never do
26945
19:20:20,464 --> 19:20:21,464
that it's not characteristic most of all
26946
19:20:23,400 --> 19:20:24,400
they have to check and double check
26947
19:20:25,616 --> 19:20:26,616
stuff and be willing to ask questions
26948
19:20:28,976 --> 19:20:29,976
so here's an example of an extremely
26949
19:20:30,832 --> 19:20:31,832
common virus that's intended to scam
26950
19:20:33,056 --> 19:20:34,056
people out of money on the on the
26951
19:20:34,680 --> 19:20:35,680
computer that's being infected the virus
26952
19:20:36,600 --> 19:20:37,600
takes over your computer and only lets
26953
19:20:38,400 --> 19:20:39,400
you see this screen or one very similar
26954
19:20:40,440 --> 19:20:41,440
to it it claims that the IP address has
26955
19:20:43,080 --> 19:20:44,080
been used to do very illegal things and
26956
19:20:45,960 --> 19:20:46,960
the FBI sees the computer and in order
26957
19:20:48,056 --> 19:20:49,056
to unlock the computer you have to pay a
26958
19:20:49,920 --> 19:20:50,920
fine or purchase a code now this virus
26959
19:20:53,216 --> 19:20:54,216
is extremely intrusive and obviously uh
26960
19:20:57,424 --> 19:20:58,424
quite
26961
19:20:58,976 --> 19:20:59,976
you know
26962
19:21:00,360 --> 19:21:01,360
um
26963
19:21:01,216 --> 19:21:02,216
successfully convincing look at all the
26964
19:21:04,464 --> 19:21:05,464
7-Eleven CVS Rite Aid all the logos at
26965
19:21:07,800 --> 19:21:08,800
the bottom Department of Justice Etc and
26966
19:21:11,160 --> 19:21:12,160
the reason they're gonna make you pay
26967
19:21:13,192 --> 19:21:14,192
through money pack it looks so real is
26968
19:21:16,080 --> 19:21:17,080
because that way they know they're
26969
19:21:18,000 --> 19:21:19,000
getting the money on the other end so
26970
19:21:20,104 --> 19:21:21,104
it's important for someone to recognize
26971
19:21:22,320 --> 19:21:23,320
that this is actually fake look on here
26972
19:21:25,080 --> 19:21:26,080
it even scares people by saying you have
26973
19:21:27,600 --> 19:21:28,600
72 hours to pay the fine or you're going
26974
19:21:29,280 --> 19:21:30,280
to be arrested
26975
19:21:30,600 --> 19:21:31,600
now someone might have been doing
26976
19:21:32,872 --> 19:21:33,872
something like downloading uh a torrent
26977
19:21:35,760 --> 19:21:36,760
off the internet and so they think oh my
26978
19:21:37,800 --> 19:21:38,800
God I'm gonna be in trouble and they
26979
19:21:39,240 --> 19:21:40,240
don't want to tell you because they
26980
19:21:40,144 --> 19:21:41,144
think they're going to get in trouble
26981
19:21:40,976 --> 19:21:41,976
with you as well we need to make sure
26982
19:21:42,896 --> 19:21:43,896
that they have a judge-free Zone in
26983
19:21:44,640 --> 19:21:45,640
which they can come tell someone and
26984
19:21:47,040 --> 19:21:48,040
that way you could remove the virus and
26985
19:21:49,376 --> 19:21:50,376
they could go on on their way and
26986
19:21:50,512 --> 19:21:51,512
continue to work
26987
19:21:52,616 --> 19:21:53,616
now as viruses and malware attacks
26988
19:21:54,960 --> 19:21:55,960
become more and more advanced anti-virus
26989
19:21:57,296 --> 19:21:58,296
software improves to combat them there
26990
19:21:59,824 --> 19:22:00,824
are thousands of antivirus software and
26991
19:22:02,280 --> 19:22:03,280
some are more advanced than you could
26992
19:22:04,144 --> 19:22:05,144
possibly even imagine it's not at the
26993
19:22:06,360 --> 19:22:07,360
ordinary however for antivirus software
26994
19:22:08,576 --> 19:22:09,576
to have automatic features so step four
26995
19:22:11,760 --> 19:22:12,760
in the mitigation strategy needs to be
26996
19:22:13,504 --> 19:22:14,504
to make sure that antivirus systems and
26997
19:22:16,800 --> 19:22:17,800
software are configured to do things
26998
19:22:19,040 --> 19:22:20,040
automatically this means they have to
26999
19:22:21,784 --> 19:22:22,784
automatically scan the computer scan the
27000
19:22:24,784 --> 19:22:25,784
network and update themselves we don't
27001
19:22:27,600 --> 19:22:28,600
want to rely on a human to do this very
27002
19:22:29,760 --> 19:22:30,760
often when it comes to virus scan
27003
19:22:31,320 --> 19:22:32,320
nothing's going to be rolled out
27004
19:22:32,464 --> 19:22:33,464
automatically that's going to damage our
27005
19:22:33,896 --> 19:22:34,896
computer so this stuff needs to happen
27006
19:22:36,120 --> 19:22:37,120
automatically when are we going to scan
27007
19:22:38,872 --> 19:22:39,872
the network well we want it to scan when
27008
19:22:41,824 --> 19:22:42,824
no one's doing anything so we want to do
27009
19:22:44,040 --> 19:22:45,040
it for instance at 2 am not at 2PM when
27010
19:22:46,800 --> 19:22:47,800
people are busy opening things and
27011
19:22:48,360 --> 19:22:49,360
closing things and that's when the virus
27012
19:22:50,696 --> 19:22:51,696
scan program won't be able to get access
27013
19:22:52,080 --> 19:22:53,080
to fifty percent of the network and
27014
19:22:54,360 --> 19:22:55,360
therefore something could be hiding out
27015
19:22:56,040 --> 19:22:57,040
this eliminates all this eliminates the
27016
19:22:59,160 --> 19:23:00,160
human element it allows for more regular
27017
19:23:01,504 --> 19:23:02,504
and controlled updates in the process
27018
19:23:03,536 --> 19:23:04,536
which is important because when we allow
27019
19:23:05,512 --> 19:23:06,512
humans in that's when errors occur
27020
19:23:08,696 --> 19:23:09,696
finally when an update to a program is
27021
19:23:10,616 --> 19:23:11,616
released it's generally to address bugs
27022
19:23:12,960 --> 19:23:13,960
that were found within a previous
27023
19:23:14,576 --> 19:23:15,576
version along with these bugs there
27024
19:23:17,040 --> 19:23:18,040
might have been some security weaknesses
27025
19:23:18,832 --> 19:23:19,832
in the software that need to be
27026
19:23:20,104 --> 19:23:21,104
addressed but program updates don't come
27027
19:23:22,744 --> 19:23:23,744
out very often in between uh updates
27028
19:23:26,640 --> 19:23:27,640
patches and so on there might be a
27029
19:23:29,280 --> 19:23:30,280
temporary fix that's released or a fix
27030
19:23:31,976 --> 19:23:32,976
that is manual that have been found so a
27031
19:23:35,400 --> 19:23:36,400
patch does exactly what you think it
27032
19:23:36,896 --> 19:23:37,896
does it basically covers a hole in the
27033
19:23:39,240 --> 19:23:40,240
software and temporarily repairs it
27034
19:23:40,920 --> 19:23:41,920
until an update or a new revision of the
27035
19:23:43,080 --> 19:23:44,080
software can come out so as soon as
27036
19:23:45,656 --> 19:23:46,656
patches or updates are released the
27037
19:23:47,696 --> 19:23:48,696
network admin needs to look at them and
27038
19:23:49,256 --> 19:23:50,256
think about installing them on the
27039
19:23:50,512 --> 19:23:51,512
network now notice that I don't
27040
19:23:52,976 --> 19:23:53,976
necessarily want you to just install it
27041
19:23:56,104 --> 19:23:57,104
right away
27042
19:23:57,536 --> 19:23:58,536
I want you to test it
27043
19:24:00,000 --> 19:24:01,000
and think about it
27044
19:24:02,280 --> 19:24:03,280
because the patch or update could very
27045
19:24:06,600 --> 19:24:07,600
well cause another problem on the
27046
19:24:08,760 --> 19:24:09,760
computer and one thing we don't want to
27047
19:24:10,496 --> 19:24:11,496
do is bring down our system because we
27048
19:24:12,720 --> 19:24:13,720
put in a new update that suddenly stops
27049
19:24:14,872 --> 19:24:15,872
our printers from working or something
27050
19:24:16,192 --> 19:24:17,192
so we need to balance this with the idea
27051
19:24:20,824 --> 19:24:21,824
that once the patch and the update is
27052
19:24:22,856 --> 19:24:23,856
released the hacker now knows that this
27053
19:24:26,040 --> 19:24:27,040
is something that they can exploit and
27054
19:24:28,016 --> 19:24:29,016
so the longer you wait to update it the
27055
19:24:30,000 --> 19:24:31,000
longer you're at risk of being exploited
27056
19:24:33,536 --> 19:24:34,536
all right so we talked about a bunch of
27057
19:24:35,576 --> 19:24:36,576
things in this module some of this is
27058
19:24:37,320 --> 19:24:38,320
common sense but these are things that
27059
19:24:38,936 --> 19:24:39,936
pop up on the network plus exam
27060
19:24:40,920 --> 19:24:41,920
first we want to Define Network
27061
19:24:42,536 --> 19:24:43,536
mitigation mitigation the word literally
27062
19:24:45,480 --> 19:24:46,480
means to lessen
27063
19:24:47,696 --> 19:24:48,696
and so what we're doing is we're
27064
19:24:49,192 --> 19:24:50,192
lessening the threats that can hit us
27065
19:24:52,080 --> 19:24:53,080
some of the steps that we identified in
27066
19:24:54,296 --> 19:24:55,296
this strategy were first to develop
27067
19:24:56,280 --> 19:24:57,280
strong policies for instance a password
27068
19:24:59,104 --> 19:25:00,104
policy is important
27069
19:25:01,144 --> 19:25:02,144
download policies
27070
19:25:04,744 --> 19:25:05,744
internet use policies
27071
19:25:08,216 --> 19:25:09,216
and so on and so forth we also need to
27072
19:25:11,104 --> 19:25:12,104
monitor threats not just internal
27073
19:25:14,576 --> 19:25:15,576
but we need to research what's going on
27074
19:25:17,336 --> 19:25:18,336
around the world so we know what the
27075
19:25:19,144 --> 19:25:20,144
latest things are that are attacking our
27076
19:25:20,576 --> 19:25:21,576
systems
27077
19:25:22,080 --> 19:25:23,080
the most important one I think is
27078
19:25:24,296 --> 19:25:25,296
educating users social engineering is
27079
19:25:27,296 --> 19:25:28,296
how hackers and attackers get around the
27080
19:25:30,784 --> 19:25:31,784
human element when there's a human
27081
19:25:32,160 --> 19:25:33,160
element there's a flaw and so we need to
27082
19:25:35,040 --> 19:25:36,040
educate users so they don't click things
27083
19:25:38,696 --> 19:25:39,696
that look bad and they know
27084
19:25:42,896 --> 19:25:43,896
when to ask questions since this can
27085
19:25:45,784 --> 19:25:46,784
help them as well
27086
19:25:47,216 --> 19:25:48,216
we also want to automate scanning and
27087
19:25:49,016 --> 19:25:50,016
updates from virus scan programs and
27088
19:25:51,720 --> 19:25:52,720
perhaps our firewall this should all
27089
19:25:54,000 --> 19:25:55,000
happen automatically
27090
19:25:58,192 --> 19:25:59,192
because if we remove the human element
27091
19:26:01,040 --> 19:26:02,040
then there's not going to be an issue we
27092
19:26:03,720 --> 19:26:04,720
also want
27093
19:26:06,056 --> 19:26:07,056
scans to happen in the middle of the
27094
19:26:07,680 --> 19:26:08,680
night when no one else is using it for
27095
19:26:10,080 --> 19:26:11,080
instance 2 am or 1 am make sure that you
27096
19:26:12,720 --> 19:26:13,720
give enough time for the scanner to
27097
19:26:14,760 --> 19:26:15,760
actually scan the entire system
27098
19:26:17,104 --> 19:26:18,104
finally we need patches and updates and
27099
19:26:19,920 --> 19:26:20,920
we want to balance
27100
19:26:21,832 --> 19:26:22,832
the patches and the updates with uh the
27101
19:26:25,744 --> 19:26:26,744
patch actually doing harm
27102
19:26:29,872 --> 19:26:30,872
versus the weakness
27103
19:26:33,296 --> 19:26:34,296
or exploit that it's correcting
27104
19:26:37,616 --> 19:26:38,616
the longer we wait
27105
19:26:40,856 --> 19:26:41,856
to employ a new patch or update
27106
19:26:44,040 --> 19:26:45,040
the longer we're at risk
27107
19:26:50,250 --> 19:26:51,250
[Music]
27108
19:26:59,600 --> 19:27:00,600
thank you
27109
19:27:06,896 --> 19:27:07,896
welcome to module 14 lesson 2A Advanced
27110
19:27:10,920 --> 19:27:11,920
threat mitigation
27111
19:27:13,192 --> 19:27:14,192
so this is new stuff for the um double
27112
19:27:16,376 --> 19:27:17,376
07 version of the com2 exam managing
27113
19:27:20,696 --> 19:27:21,696
your signatures hardening your devices
27114
19:27:23,360 --> 19:27:24,360
in terms of security that is changing
27115
19:27:26,512 --> 19:27:27,512
your native VLAN
27116
19:27:28,800 --> 19:27:29,800
switch Port protection
27117
19:27:31,856 --> 19:27:32,856
restricting access with access lists
27118
19:27:34,320 --> 19:27:35,320
Honeypot and honey net uh penetration
27119
19:27:37,680 --> 19:27:38,680
testing so signatures in terms of
27120
19:27:40,920 --> 19:27:41,920
signature management we're talking about
27121
19:27:42,424 --> 19:27:43,424
IDs and IPS which we've covered earlier
27122
19:27:45,784 --> 19:27:46,784
the signature-based detection examines
27123
19:27:48,056 --> 19:27:49,056
Network traffic for pre-configured and
27124
19:27:50,104 --> 19:27:51,104
predetermined attacks so the signature
27125
19:27:52,440 --> 19:27:53,440
is the thing that is matched against in
27126
19:27:55,256 --> 19:27:56,256
these devices the threat the threat
27127
19:27:57,480 --> 19:27:58,480
signature
27128
19:27:58,616 --> 19:27:59,616
these are known as signatures attacker
27129
19:28:01,976 --> 19:28:02,976
um convinces employee to disclose
27130
19:28:03,920 --> 19:28:04,920
confidential information
27131
19:28:06,656 --> 19:28:07,656
if adult signature is identified by the
27132
19:28:08,640 --> 19:28:09,640
system an alarm is triggered or the
27133
19:28:10,856 --> 19:28:11,856
traffic will be blocked this it depends
27134
19:28:12,720 --> 19:28:13,720
on how you've configured your
27135
19:28:15,656 --> 19:28:16,656
um IDs and IPS so it will either
27136
19:28:19,144 --> 19:28:20,144
um send an SNMP alert or create some
27137
19:28:22,976 --> 19:28:23,976
sort of log message or whatever you've
27138
19:28:25,080 --> 19:28:26,080
designed it to do the signature codes
27139
19:28:28,080 --> 19:28:29,080
are updated or they should be updated
27140
19:28:29,640 --> 19:28:30,640
regularly for new or false patterns you
27141
19:28:32,640 --> 19:28:33,640
don't you really don't want false
27142
19:28:33,960 --> 19:28:34,960
positives either because it's just going
27143
19:28:35,400 --> 19:28:36,400
to be in traffic's blocked when it
27144
19:28:37,616 --> 19:28:38,616
shouldn't be
27145
19:28:38,872 --> 19:28:39,872
uh there's a website called threat
27146
19:28:41,480 --> 19:28:42,480
threatconnect.com they offer some sort
27147
19:28:43,744 --> 19:28:44,744
of signature management uh system for
27148
19:28:47,280 --> 19:28:48,280
for you to look after all your
27149
19:28:48,424 --> 19:28:49,424
signatures uh I I only suggest it
27150
19:28:51,056 --> 19:28:52,056
because I use their graphic and I wanted
27151
19:28:53,160 --> 19:28:54,160
to credit them for that but this is what
27152
19:28:55,144 --> 19:28:56,144
came up when I was researching threat
27153
19:28:57,176 --> 19:28:58,176
signatures
27154
19:28:58,976 --> 19:28:59,976
device hardening this is part of your
27155
19:29:01,504 --> 19:29:02,504
daily weekly monthly admin task
27156
19:29:05,640 --> 19:29:06,640
especially if you're in charge of
27157
19:29:07,376 --> 19:29:08,376
security
27158
19:29:08,176 --> 19:29:09,176
for uh looking after your network
27159
19:29:11,040 --> 19:29:12,040
you'll Pat your update software or
27160
19:29:13,144 --> 19:29:14,144
firmware in your Hardware devices
27161
19:29:16,320 --> 19:29:17,320
check for non-compliant passwords this
27162
19:29:19,440 --> 19:29:20,440
will obviously part of your password
27163
19:29:20,464 --> 19:29:21,464
policy but I'm sure you've logged into
27164
19:29:23,464 --> 19:29:24,464
something or had an email updating you
27165
19:29:26,760 --> 19:29:27,760
saying that your current password isn't
27166
19:29:29,160 --> 19:29:30,160
um strong enough and you need to update
27167
19:29:30,600 --> 19:29:31,600
it
27168
19:29:31,680 --> 19:29:32,680
removing redundant networks and IP
27169
19:29:33,832 --> 19:29:34,832
addresses strangely enough I've known
27170
19:29:36,536 --> 19:29:37,536
equipment found years after people
27171
19:29:39,960 --> 19:29:40,960
thought it had been decommissioned it's
27172
19:29:41,512 --> 19:29:42,512
sitting in a office somewhere plugged
27173
19:29:43,440 --> 19:29:44,440
into the network and nobody knew it was
27174
19:29:45,896 --> 19:29:46,896
there and this can then be a back door
27175
19:29:48,176 --> 19:29:49,176
for hackers to find and get into your
27176
19:29:50,824 --> 19:29:51,824
network changing security keys
27177
19:29:54,360 --> 19:29:55,360
are changing the native VLAN so the
27178
19:29:56,872 --> 19:29:57,872
native VLAN is used for any untagged
27179
19:29:59,872 --> 19:30:00,872
traffic on your network you'll be
27180
19:30:02,464 --> 19:30:03,464
familiar with this when you start doing
27181
19:30:03,896 --> 19:30:04,896
Cisco configuration or any type of
27182
19:30:06,960 --> 19:30:07,960
juniper or the other network management
27183
19:30:10,616 --> 19:30:11,616
big security vulnerability your native
27184
19:30:13,320 --> 19:30:14,320
VLAN is passes important information
27185
19:30:16,320 --> 19:30:17,320
such as
27186
19:30:18,424 --> 19:30:19,424
um your Cisco Discovery protocol or the
27187
19:30:21,056 --> 19:30:22,056
equivalent which is device information
27188
19:30:24,656 --> 19:30:25,656
foreign
27189
19:30:26,296 --> 19:30:27,296
your operating system that it's running
27190
19:30:29,040 --> 19:30:30,040
etc etc a dynamic drinking protocol is
27191
19:30:31,680 --> 19:30:32,680
for uh trunking so your native VLAN will
27192
19:30:36,000 --> 19:30:37,000
normally go across a trunk link and
27193
19:30:39,360 --> 19:30:40,360
you've got all of this important
27194
19:30:40,552 --> 19:30:41,552
information
27195
19:30:41,480 --> 19:30:42,480
on The Cisco devices certainly and
27196
19:30:44,216 --> 19:30:45,216
probably a lot of other vendors the
27197
19:30:46,440 --> 19:30:47,440
native VLAN is VLAN one and if you leave
27198
19:30:49,504 --> 19:30:50,504
this as the VLAN that the switches can
27199
19:30:53,400 --> 19:30:54,400
communicate with you've left a possible
27200
19:30:55,616 --> 19:30:56,616
security vulnerability
27201
19:30:58,080 --> 19:30:59,080
because this traffic is actually
27202
19:30:59,696 --> 19:31:00,696
untagged
27203
19:31:01,192 --> 19:31:02,192
so what you want to do is on any drunk
27204
19:31:03,832 --> 19:31:04,832
leg trunk link you change it to an
27205
19:31:06,784 --> 19:31:07,784
unused VLAN
27206
19:31:09,600 --> 19:31:10,600
so this is one that isn't been used on
27207
19:31:12,296 --> 19:31:13,296
um
27208
19:31:13,192 --> 19:31:14,192
so you've got to VLAN 10 20
27209
19:31:16,744 --> 19:31:17,744
30 and 40. you would use your an unused
27210
19:31:20,464 --> 19:31:21,464
VLAN on your trunk links for example
27211
19:31:23,104 --> 19:31:24,104
um
27212
19:31:24,056 --> 19:31:25,056
two two two just something fairly high
27213
19:31:27,000 --> 19:31:28,000
and then another trunk link to another
27214
19:31:29,512 --> 19:31:30,512
switch
27215
19:31:31,440 --> 19:31:32,440
you'd have another VLAN for example two
27216
19:31:34,016 --> 19:31:35,016
two three
27217
19:31:35,280 --> 19:31:36,280
Etc
27218
19:31:38,280 --> 19:31:39,280
is the output for a Cisco device and you
27219
19:31:41,336 --> 19:31:42,336
can see this is trunk in so it's passing
27220
19:31:43,856 --> 19:31:44,856
multiple vlans on this link but the
27221
19:31:46,976 --> 19:31:47,976
native VLAN is uh VLAN one
27222
19:31:51,656 --> 19:31:52,656
so I've wiped over it there the native
27223
19:31:53,512 --> 19:31:54,512
VLAN is VLAN one which you don't want so
27224
19:31:56,160 --> 19:31:57,160
what I did I went to the trunk interface
27225
19:31:59,104 --> 19:32:00,104
here I issued the command switchbot
27226
19:32:01,320 --> 19:32:02,320
trunk native VLAN five
27227
19:32:04,920 --> 19:32:05,920
you'll probably use something higher
27228
19:32:06,720 --> 19:32:07,720
like I said like two two but it's just
27229
19:32:08,760 --> 19:32:09,760
to illustrate the point so this traffic
27230
19:32:11,280 --> 19:32:12,280
that passes over uh the native VLAN will
27231
19:32:14,760 --> 19:32:15,760
use VLAN F5 it won't use VLAN one and
27232
19:32:18,120 --> 19:32:19,120
you've got to be careful because you
27233
19:32:19,440 --> 19:32:20,440
can't delete a VLAN one it's there all
27234
19:32:22,552 --> 19:32:23,552
the time you just don't have to use it
27235
19:32:24,656 --> 19:32:25,656
to pass any traffic and now you can see
27236
19:32:27,000 --> 19:32:28,000
it's changed from VLAN one as a default
27237
19:32:29,280 --> 19:32:30,280
to VLAN 5.
27238
19:32:36,192 --> 19:32:37,192
I've already mentioned all this sorry so
27239
19:32:39,056 --> 19:32:40,056
another thing mentioned is bpdu guard
27240
19:32:42,440 --> 19:32:43,440
this is arrived in the syllabus
27241
19:32:45,360 --> 19:32:46,360
a bpdu guard it's on an interface the
27242
19:32:48,784 --> 19:32:49,784
port is every disabled when a bpdu is
27243
19:32:51,536 --> 19:32:52,536
received so Bridge protocol data unit we
27244
19:32:54,480 --> 19:32:55,480
talked about earlier this is uh used for
27245
19:32:57,176 --> 19:32:58,176
spanning tree traffic
27246
19:32:59,576 --> 19:33:00,576
and it can actually change your layer 2
27247
19:33:01,256 --> 19:33:02,256
topologies for example let's say this
27248
19:33:04,680 --> 19:33:05,680
switch is the root you've got a high a
27249
19:33:06,832 --> 19:33:07,832
high-powered switch here and it would
27250
19:33:09,176 --> 19:33:10,176
normally be a multi-layer switch here
27251
19:33:12,376 --> 19:33:13,376
and all of your traffic is pointing to
27252
19:33:15,720 --> 19:33:16,720
this device but what will happen is this
27253
19:33:18,536 --> 19:33:19,536
device will announce a number
27254
19:33:21,056 --> 19:33:22,056
to say I am the boss and say for example
27255
19:33:24,056 --> 19:33:25,056
this is number 99. this is the number
27256
19:33:27,720 --> 19:33:28,720
that determines the root of all your
27257
19:33:29,512 --> 19:33:30,512
spanning tree traffic well what happens
27258
19:33:31,680 --> 19:33:32,680
is if this device uh connects to the
27259
19:33:34,016 --> 19:33:35,016
network say you've bought you've found
27260
19:33:35,512 --> 19:33:36,512
it on a Shelf at work and for some crazy
27261
19:33:38,400 --> 19:33:39,400
reason all you've done is plug it in and
27262
19:33:40,856 --> 19:33:41,856
this has happened by the way I've seen
27263
19:33:42,240 --> 19:33:43,240
it happen well this device could
27264
19:33:44,696 --> 19:33:45,696
actually be configured with the number
27265
19:33:47,040 --> 19:33:48,040
100
27266
19:33:48,480 --> 19:33:49,480
in terms of um spanning tree and what
27267
19:33:51,240 --> 19:33:52,240
could happen is then or this could be a
27268
19:33:53,400 --> 19:33:54,400
really low switch is worth about say a
27269
19:33:56,040 --> 19:33:57,040
hundred dollars and it's just got a tiny
27270
19:33:57,960 --> 19:33:58,960
amount of process and power all of your
27271
19:34:00,800 --> 19:34:01,800
spanning tree traffic all of a sudden
27272
19:34:03,120 --> 19:34:04,120
will be converging onto this tiny little
27273
19:34:06,176 --> 19:34:07,176
switch the CPU will go from almost
27274
19:34:08,640 --> 19:34:09,640
nothing through the roof it'll probably
27275
19:34:11,104 --> 19:34:12,104
crash bring you down your entire local
27276
19:34:12,832 --> 19:34:13,832
area network and at that point you'll
27277
19:34:14,936 --> 19:34:15,936
probably be out of a job to be honest
27278
19:34:17,872 --> 19:34:18,872
so what happens is with bpdu guard you
27279
19:34:20,576 --> 19:34:21,576
configure it on this interface here for
27280
19:34:22,552 --> 19:34:23,552
example fast ethernet and 10 and if a BP
27281
19:34:26,512 --> 19:34:27,512
do you frame is seen coming in onto this
27282
19:34:30,784 --> 19:34:31,784
particular interface it will error
27283
19:34:32,824 --> 19:34:33,824
disable
27284
19:34:33,832 --> 19:34:34,832
um it will error disable it and it won't
27285
19:34:36,000 --> 19:34:37,000
pass traffic until you the network
27286
19:34:37,744 --> 19:34:38,744
administrator
27287
19:34:40,440 --> 19:34:41,440
um what come comes shuts it manually and
27288
19:34:44,216 --> 19:34:45,216
then manually no shits the interface so
27289
19:34:46,680 --> 19:34:47,680
you have to re-enable it
27290
19:34:48,600 --> 19:34:49,600
uh root guard
27291
19:34:51,536 --> 19:34:52,536
so I mentioned uh if this is a topology
27292
19:34:54,240 --> 19:34:55,240
where it's actually I think from my CCNA
27293
19:34:56,936 --> 19:34:57,936
book where I'm telling you on what
27294
19:34:59,160 --> 19:35:00,160
interfaces depending on the topology you
27295
19:35:01,320 --> 19:35:02,320
would add bpdu guard root guard you
27296
19:35:04,144 --> 19:35:05,144
would add down here
27297
19:35:06,656 --> 19:35:07,656
on these level of interfaces so these
27298
19:35:09,600 --> 19:35:10,600
are your layer 3 switches and these are
27299
19:35:12,536 --> 19:35:13,536
your these images here represent Layer
27300
19:35:14,576 --> 19:35:15,576
Two
27301
19:35:15,600 --> 19:35:16,600
uh root guard is configured per Port so
27302
19:35:18,000 --> 19:35:19,000
you wouldn't configure it on a device
27303
19:35:19,680 --> 19:35:20,680
and expect the configuration to be
27304
19:35:21,784 --> 19:35:22,784
passed out through your network
27305
19:35:23,696 --> 19:35:24,696
and like um other configurations root
27306
19:35:27,424 --> 19:35:28,424
ports are the closest to the spanning
27307
19:35:29,160 --> 19:35:30,160
tree master these ports are furthest
27308
19:35:32,336 --> 19:35:33,336
away if this is the master here in my
27309
19:35:35,160 --> 19:35:36,160
topology
27310
19:35:36,680 --> 19:35:37,680
these are the ports that would normally
27311
19:35:39,536 --> 19:35:40,536
you would want to be root and it's
27312
19:35:41,872 --> 19:35:42,872
basically saying the root equals
27313
19:35:45,056 --> 19:35:46,056
um best
27314
19:35:46,496 --> 19:35:47,496
path to take to the master this is not
27315
19:35:50,696 --> 19:35:51,696
the best path to take to the master this
27316
19:35:53,216 --> 19:35:54,216
would cause you a lot of problems this
27317
19:35:55,080 --> 19:35:56,080
is why you would enable root guard on
27318
19:35:57,360 --> 19:35:58,360
these ports here
27319
19:35:59,400 --> 19:36:00,400
so Modesto for incoming Bridge protocol
27320
19:36:01,800 --> 19:36:02,800
data units
27321
19:36:03,656 --> 19:36:04,656
and it prevents support from becoming a
27322
19:36:05,640 --> 19:36:06,640
root Port how it does it yeah you can
27323
19:36:08,104 --> 19:36:09,104
learn a bit more when you do Cisco CCNA
27324
19:36:10,856 --> 19:36:11,856
and ccmp Etc
27325
19:36:12,920 --> 19:36:13,920
DHCP snooping this is the uh legitimate
27326
19:36:18,424 --> 19:36:19,424
one
27327
19:36:19,440 --> 19:36:20,440
here this is the Rogue that somebody's
27328
19:36:22,256 --> 19:36:23,256
either somebody's attached it to your
27329
19:36:24,296 --> 19:36:25,296
network or they've downloaded some code
27330
19:36:27,920 --> 19:36:28,920
accidentally onto their device and it's
27331
19:36:31,440 --> 19:36:32,440
trying to take over as a DHCP server for
27332
19:36:34,080 --> 19:36:35,080
this segment of your network which you
27333
19:36:36,536 --> 19:36:37,536
don't want to happen
27334
19:36:38,216 --> 19:36:39,216
it forces the switch here to examine and
27335
19:36:41,400 --> 19:36:42,400
filter inappropriate DHCP messages so if
27336
19:36:45,000 --> 19:36:46,000
this port if this switch detects it
27337
19:36:47,280 --> 19:36:48,280
coming on this port you've configured
27338
19:36:49,616 --> 19:36:50,616
this port here as interested
27339
19:36:55,376 --> 19:36:56,376
and you know which ports you trust
27340
19:36:57,120 --> 19:36:58,120
because you're the network administrator
27341
19:36:58,464 --> 19:36:59,464
this port
27342
19:37:03,600 --> 19:37:04,600
so it comes in and that is permitted
27343
19:37:06,240 --> 19:37:07,240
through untrusted it comes in and
27344
19:37:09,720 --> 19:37:10,720
blocked and then you would normally get
27345
19:37:12,176 --> 19:37:13,176
notified as the administrator that hang
27346
19:37:14,696 --> 19:37:15,696
on something's not quite right here with
27347
19:37:17,040 --> 19:37:18,040
a text phone call or other type of alert
27348
19:37:21,360 --> 19:37:22,360
uh vlans these separate your host into
27349
19:37:23,936 --> 19:37:24,936
function so here you've got the sales
27350
19:37:25,440 --> 19:37:26,440
team you're accounting uh Team the IT
27351
19:37:29,464 --> 19:37:30,464
team and then your human resources and
27352
19:37:32,512 --> 19:37:33,512
what this does and it depends on the
27353
19:37:34,680 --> 19:37:35,680
design methodology you're following by
27354
19:37:37,320 --> 19:37:38,320
the way there's a whole bunch of ways to
27355
19:37:39,120 --> 19:37:40,120
design your network depending on which
27356
19:37:41,216 --> 19:37:42,216
vendor you're speaking to but we've
27357
19:37:43,504 --> 19:37:44,504
separated ours into functions
27358
19:37:46,800 --> 19:37:47,800
now if there's a broadcast say there's a
27359
19:37:49,192 --> 19:37:50,192
a fault on the network card for this
27360
19:37:51,784 --> 19:37:52,784
device here
27361
19:37:53,464 --> 19:37:54,464
then um the broadcast traffic because
27362
19:37:56,512 --> 19:37:57,512
each VLAN has its own network address so
27363
19:38:00,424 --> 19:38:01,424
say that's in 10.10
27364
19:38:03,536 --> 19:38:04,536
uh 10.20
27365
19:38:06,832 --> 19:38:07,832
10.30
27366
19:38:10,016 --> 19:38:11,016
and uh
27367
19:38:11,696 --> 19:38:12,696
10.40
27368
19:38:14,160 --> 19:38:15,160
so these are all different
27369
19:38:16,496 --> 19:38:17,496
um subnets and in order for these to
27370
19:38:19,440 --> 19:38:20,440
communicate you'd either have to have a
27371
19:38:21,360 --> 19:38:22,360
layer 3 module in this switch or the
27372
19:38:24,360 --> 19:38:25,360
switch would be connected to a router as
27373
19:38:26,216 --> 19:38:27,216
we've spoke about earlier if there's a
27374
19:38:28,376 --> 19:38:29,376
broadcast through this faulty network
27375
19:38:30,056 --> 19:38:31,056
card here it's basically restricted to
27376
19:38:33,424 --> 19:38:34,424
all devices on this VLAN
27377
19:38:36,296 --> 19:38:37,296
and then what would happen is the the
27378
19:38:38,216 --> 19:38:39,216
your phone would go somebody would call
27379
19:38:40,376 --> 19:38:41,376
tech support and
27380
19:38:42,424 --> 19:38:43,424
um it would help you in your
27381
19:38:43,504 --> 19:38:44,504
troubleshooting because the broadcast
27382
19:38:45,496 --> 19:38:46,496
isn't affecting everyone here but
27383
19:38:48,600 --> 19:38:49,600
basically you're told that um everyone
27384
19:38:51,176 --> 19:38:52,176
in the sales team is getting a really
27385
19:38:53,280 --> 19:38:54,280
slow Network response and then this this
27386
19:38:56,576 --> 19:38:57,576
um this is known as the divide and
27387
19:38:58,080 --> 19:38:59,080
conquer method of troubleshooting you
27388
19:39:00,424 --> 19:39:01,424
know that everyone here is affected
27389
19:39:02,400 --> 19:39:03,400
and then so you'd be looking at these
27390
19:39:04,800 --> 19:39:05,800
ports on the switch you could use a the
27391
19:39:07,192 --> 19:39:08,192
sniffer the network sniffer and you'd
27392
19:39:10,744 --> 19:39:11,744
probably quite quickly see the IP
27393
19:39:12,120 --> 19:39:13,120
address dot one is sending out normal
27394
19:39:14,936 --> 19:39:15,936
about traffic and then it's gone through
27395
19:39:16,616 --> 19:39:17,616
the roof whereas all the other devices
27396
19:39:18,832 --> 19:39:19,832
on this particular and segment of
27397
19:39:21,600 --> 19:39:22,600
sending a normal amount of traffic
27398
19:39:27,536 --> 19:39:28,536
access lists and these can be used to
27399
19:39:31,192 --> 19:39:32,192
block an entire network or subnet one
27400
19:39:34,440 --> 19:39:35,440
particular host or a number of hosts a
27401
19:39:37,192 --> 19:39:38,192
particular port number or a protocol so
27402
19:39:40,744 --> 19:39:41,744
um icmp or
27403
19:39:43,744 --> 19:39:44,744
um
27404
19:39:44,280 --> 19:39:45,280
whatever you want
27405
19:39:47,216 --> 19:39:48,216
airport numbers could be anything dhep
27406
19:39:49,680 --> 19:39:50,680
DNS host dot one and then obviously
27407
19:39:55,376 --> 19:39:56,376
entire Networks
27408
19:39:57,480 --> 19:39:58,480
so it's a list of permitted or denied
27409
19:39:59,872 --> 19:40:00,872
traffic so if you don't worry about the
27410
19:40:02,760 --> 19:40:03,760
uh text here because you're not expected
27411
19:40:04,616 --> 19:40:05,616
to know this for the exam you've give
27412
19:40:06,656 --> 19:40:07,656
you've created an access list and you've
27413
19:40:08,936 --> 19:40:09,936
said do you know this traffic icmp and
27414
19:40:12,120 --> 19:40:13,120
permits IP traffic and what happens is
27415
19:40:15,056 --> 19:40:16,056
the access list always processed top to
27416
19:40:17,760 --> 19:40:18,760
bottom I've only got two two entries on
27417
19:40:20,160 --> 19:40:21,160
this so it'll be pretty quick actually
27418
19:40:21,960 --> 19:40:22,960
but as soon as the access to this reach
27419
19:40:24,424 --> 19:40:25,424
is aligned so say it's icmp traffic it
27420
19:40:27,784 --> 19:40:28,784
would reach this particular line
27421
19:40:29,936 --> 19:40:30,936
and then it would be a match and it
27422
19:40:32,040 --> 19:40:33,040
would be denied the access this wouldn't
27423
19:40:34,256 --> 19:40:35,256
go all the way to the bottom if it's not
27424
19:40:36,656 --> 19:40:37,656
icmp traffic it would reach the next
27425
19:40:38,824 --> 19:40:39,824
item on your list and the chances are
27426
19:40:41,336 --> 19:40:42,336
it's going to be some other sort of Ip
27427
19:40:44,216 --> 19:40:45,216
traffic and it would be permitted
27428
19:40:49,976 --> 19:40:50,976
honey pot honey net honey pots attract
27429
19:40:52,496 --> 19:40:53,496
possible attackers into an isolated
27430
19:40:54,296 --> 19:40:55,296
environment
27431
19:40:56,464 --> 19:40:57,464
so this is your attacker and it's a
27432
19:40:58,800 --> 19:40:59,800
potential victim and what they don't
27433
19:41:00,832 --> 19:41:01,832
know or they should know is they've
27434
19:41:02,640 --> 19:41:03,640
actually been fooled into redirecting
27435
19:41:04,680 --> 19:41:05,680
into this
27436
19:41:05,824 --> 19:41:06,824
um new net system they can't do any harm
27437
19:41:08,824 --> 19:41:09,824
in this place and what you can do
27438
19:41:12,480 --> 19:41:13,480
is this is a pair of binoculars I know
27439
19:41:15,480 --> 19:41:16,480
it's absolutely Dreadful isn't it
27440
19:41:17,872 --> 19:41:18,872
this is you as the network administrator
27441
19:41:20,240 --> 19:41:21,240
watching what they do you'll obviously
27442
19:41:23,216 --> 19:41:24,216
be doing it via whatever software and
27443
19:41:24,720 --> 19:41:25,720
you can see what commands are executing
27444
19:41:26,464 --> 19:41:27,464
and trying to inject pieces of code and
27445
19:41:29,040 --> 19:41:30,040
this whole environment here is um
27446
19:41:31,616 --> 19:41:32,616
protected is segmented off from your
27447
19:41:33,296 --> 19:41:34,296
network and then that that lets you
27448
19:41:35,640 --> 19:41:36,640
design a series of steps to protect your
27449
19:41:38,936 --> 19:41:39,936
network so you're analyzing the behavior
27450
19:41:41,104 --> 19:41:42,104
and Gathering the information if it's a
27451
19:41:43,744 --> 19:41:44,744
honey net it's basically a chain of
27452
19:41:45,656 --> 19:41:46,656
Honey pots so you've got you've got your
27453
19:41:47,936 --> 19:41:48,936
honey pot here and but what you've done
27454
19:41:50,216 --> 19:41:51,216
is you've chained them together for
27455
19:41:53,160 --> 19:41:54,160
whatever reason
27456
19:41:55,256 --> 19:41:56,256
I usually place in um Network segments
27457
19:41:58,080 --> 19:41:59,080
this will this will be isolated by your
27458
19:42:00,480 --> 19:42:01,480
firewall so they're coming in and they
27459
19:42:03,120 --> 19:42:04,120
get redirected to your firewall this is
27460
19:42:05,280 --> 19:42:06,280
actually your local area network over
27461
19:42:07,504 --> 19:42:08,504
here
27462
19:42:11,400 --> 19:42:12,400
sting uh comment here have actually got
27463
19:42:13,440 --> 19:42:14,440
the um
27464
19:42:15,656 --> 19:42:16,656
the pen test certification out I'm
27465
19:42:18,832 --> 19:42:19,832
looking into adding it now
27466
19:42:21,360 --> 19:42:22,360
um so keep your eyes open it scans your
27467
19:42:24,360 --> 19:42:25,360
network in order to find ports or
27468
19:42:25,976 --> 19:42:26,976
protocols with floors I've talked about
27469
19:42:27,960 --> 19:42:28,960
this kind of stuff before part of your
27470
19:42:30,056 --> 19:42:31,056
regular security ordering and audition
27471
19:42:32,576 --> 19:42:33,576
process so say every every Monday you
27472
19:42:36,240 --> 19:42:37,240
carry out this particular
27473
19:42:38,040 --> 19:42:39,040
um test on your network
27474
19:42:39,720 --> 19:42:40,720
it can simulate a type of attack and
27475
19:42:43,320 --> 19:42:44,320
um it's well recommended that you you do
27476
19:42:45,176 --> 19:42:46,176
this so we've covered a lot of stuff
27477
19:42:47,160 --> 19:42:48,160
here
27478
19:42:48,360 --> 19:42:49,360
um managing your signatures device
27479
19:42:50,040 --> 19:42:51,040
hardening changing your native VLAN must
27480
19:42:52,744 --> 19:42:53,744
do protecting your ports
27481
19:42:55,440 --> 19:42:56,440
we looked at um
27482
19:42:58,016 --> 19:42:59,016
protecting it from the STP packets
27483
19:43:00,784 --> 19:43:01,784
coming in the bridge protocol data units
27484
19:43:04,376 --> 19:43:05,376
so we don't it doesn't become a root
27485
19:43:08,280 --> 19:43:09,280
or um and it doesn't change the
27486
19:43:11,160 --> 19:43:12,160
um it doesn't become a report and it
27487
19:43:13,504 --> 19:43:14,504
doesn't become the STP
27488
19:43:15,656 --> 19:43:16,656
um root either both very bad things for
27489
19:43:18,176 --> 19:43:19,176
your network
27490
19:43:19,552 --> 19:43:20,552
access lists Honeypot and honey Nets and
27491
19:43:23,040 --> 19:43:24,040
then penetration testing so that's all
27492
19:43:25,256 --> 19:43:26,256
for now thanks for watching
27493
19:43:37,610 --> 19:43:38,610
[Music]
27494
19:43:54,536 --> 19:43:55,536
welcome to module 14 lesson three
27495
19:43:57,080 --> 19:43:58,080
policies and best practices
27496
19:44:02,280 --> 19:44:03,280
a few things we want to cover here the
27497
19:44:04,256 --> 19:44:05,256
privileged user agreement your password
27498
19:44:06,536 --> 19:44:07,536
policy
27499
19:44:07,920 --> 19:44:08,920
on off-boarding
27500
19:44:10,376 --> 19:44:11,376
which is when people join your business
27501
19:44:12,360 --> 19:44:13,360
and leave whatever reason
27502
19:44:14,936 --> 19:44:15,936
your licensing restrictions restrictions
27503
19:44:17,696 --> 19:44:18,696
International export controls
27504
19:44:21,144 --> 19:44:22,144
preventing data loss and remote access
27505
19:44:24,056 --> 19:44:25,056
policies
27506
19:44:26,512 --> 19:44:27,512
incident response policies bring your
27507
19:44:29,464 --> 19:44:30,464
own device
27508
19:44:33,360 --> 19:44:34,360
acceptable use policy your
27509
19:44:35,824 --> 19:44:36,824
non-disclosure agreement
27510
19:44:37,976 --> 19:44:38,976
uh system life cycle and safety
27511
19:44:41,640 --> 19:44:42,640
so your privileged user the privileged
27512
19:44:44,464 --> 19:44:45,464
users are people you could call them
27513
19:44:45,896 --> 19:44:46,896
super users or administrators whatever
27514
19:44:49,016 --> 19:44:50,016
this um agreement should be signed by
27515
19:44:51,784 --> 19:44:52,784
administrators
27516
19:44:53,280 --> 19:44:54,280
so the Crux of it is that they should
27517
19:44:55,976 --> 19:44:56,976
only be using the networking tools for
27518
19:44:58,080 --> 19:44:59,080
job purposes I know where I where I
27519
19:45:01,192 --> 19:45:02,192
worked at this um ISP we all worked in
27520
19:45:04,440 --> 19:45:05,440
the um
27521
19:45:05,960 --> 19:45:06,960
the admin team we were doing the network
27522
19:45:08,400 --> 19:45:09,400
support for large customers and then
27523
19:45:10,744 --> 19:45:11,744
obviously there was a whole bunch of
27524
19:45:12,320 --> 19:45:13,320
teams under us here
27525
19:45:15,536 --> 19:45:16,536
like a HR
27526
19:45:21,000 --> 19:45:22,000
Finance Etc but none of these could get
27527
19:45:24,120 --> 19:45:25,120
out to their social media this is say
27528
19:45:27,480 --> 19:45:28,480
for example Facebook that was blocked
27529
19:45:29,824 --> 19:45:30,824
but the admin team they could obviously
27530
19:45:32,040 --> 19:45:33,040
decide what went in and out of the
27531
19:45:33,720 --> 19:45:34,720
network so they let themselves get out
27532
19:45:35,512 --> 19:45:36,512
on Facebook eBay whatever they wanted so
27533
19:45:39,600 --> 19:45:40,600
um we didn't actually have a user
27534
19:45:41,104 --> 19:45:42,104
agreement there we just got hired and we
27535
19:45:42,720 --> 19:45:43,720
started working but really the point of
27536
19:45:44,760 --> 19:45:45,760
a user agreement is you're not doing
27537
19:45:46,144 --> 19:45:47,144
things for the network or giving people
27538
19:45:48,600 --> 19:45:49,600
access to things that aren't really work
27539
19:45:50,464 --> 19:45:51,464
related
27540
19:45:51,720 --> 19:45:52,720
so access only areas that are under your
27541
19:45:54,296 --> 19:45:55,296
purview so as the administrator you may
27542
19:45:57,360 --> 19:45:58,360
or may not be able to configure ways of
27543
19:45:59,336 --> 19:46:00,336
you getting into firewalls and other
27544
19:46:01,192 --> 19:46:02,192
devices that you might not manage but
27545
19:46:03,480 --> 19:46:04,480
the agreement that you've signed should
27546
19:46:05,104 --> 19:46:06,104
prevent you from doing that
27547
19:46:06,960 --> 19:46:07,960
user accounts only changed under company
27548
19:46:09,832 --> 19:46:10,832
policy and with correct authorization so
27549
19:46:13,192 --> 19:46:14,192
this would be something like a friend of
27550
19:46:14,760 --> 19:46:15,760
yours that's asked to to get out on some
27551
19:46:17,760 --> 19:46:18,760
device or they're asking if they can and
27552
19:46:20,512 --> 19:46:21,512
access their emails from their home
27553
19:46:22,256 --> 19:46:23,256
computer these things that you might be
27554
19:46:24,784 --> 19:46:25,784
asked to do but you you shouldn't be
27555
19:46:26,512 --> 19:46:27,512
allowed to do
27556
19:46:28,080 --> 19:46:29,080
your password policy uh I've actually
27557
19:46:31,192 --> 19:46:32,192
seen a few
27558
19:46:32,464 --> 19:46:33,464
um News interviews especially in the
27559
19:46:34,976 --> 19:46:35,976
last couple of years
27560
19:46:36,720 --> 19:46:37,720
of people giving interviews when they're
27561
19:46:39,056 --> 19:46:40,056
at work and you can actually see a
27562
19:46:41,104 --> 19:46:42,104
Post-It note on their monitor yeah
27563
19:46:43,800 --> 19:46:44,800
saying what their password is
27564
19:46:46,496 --> 19:46:47,496
so this is obviously a big No-No some of
27565
19:46:49,256 --> 19:46:50,256
the things that you maybe maybe
27566
19:46:51,176 --> 19:46:52,176
implemented are they're no reuse or
27567
19:46:53,824 --> 19:46:54,824
changing the last character such as a if
27568
19:46:56,936 --> 19:46:57,936
your password is a b c d e f g one you
27569
19:47:02,280 --> 19:47:03,280
wouldn't be allowed to change it to all
27570
19:47:04,080 --> 19:47:05,080
be the same and then two on the end
27571
19:47:06,176 --> 19:47:07,176
obviously for the work Network
27572
19:47:09,000 --> 19:47:10,000
no writing on Post-it notes expiry
27573
19:47:11,872 --> 19:47:12,872
length again this is all a pain because
27574
19:47:13,744 --> 19:47:14,744
people are going to be forgetting their
27575
19:47:15,176 --> 19:47:16,176
passwords and logging tickets it just
27576
19:47:17,336 --> 19:47:18,336
depends how secure your environment is
27577
19:47:19,920 --> 19:47:20,920
upper lower case is pretty common plus
27578
19:47:22,552 --> 19:47:23,552
special characters and numbers
27579
19:47:25,160 --> 19:47:26,160
non-dictionary words so again you could
27580
19:47:28,680 --> 19:47:29,680
be just looking at
27581
19:47:30,784 --> 19:47:31,784
and people choose things they're going
27582
19:47:32,464 --> 19:47:33,464
to remember like um
27583
19:47:37,616 --> 19:47:38,616
I think there's only one Ellen Bloom but
27584
19:47:39,656 --> 19:47:40,656
you know what I mean balloon kite teacup
27585
19:47:42,656 --> 19:47:43,656
all these kind of things are they
27586
19:47:45,240 --> 19:47:46,240
allowed to use passive password
27587
19:47:46,616 --> 19:47:47,616
management software I've got password
27588
19:47:49,080 --> 19:47:50,080
management because I've got maybe 150
27589
19:47:53,216 --> 19:47:54,216
different types of software and service
27590
19:47:56,696 --> 19:47:57,696
I use I've managed about I've got about
27591
19:47:59,872 --> 19:48:00,872
14 15 websites some I'm on every day and
27592
19:48:03,360 --> 19:48:04,360
some I only check in once a year maybe
27593
19:48:06,176 --> 19:48:07,176
but I mean just to try to imagine you
27594
19:48:08,336 --> 19:48:09,336
can't have the same password for all of
27595
19:48:09,720 --> 19:48:10,720
these or you shouldn't so try to manage
27596
19:48:11,576 --> 19:48:12,576
them this is a bit too difficult it's a
27597
19:48:13,856 --> 19:48:14,856
robo form I think it's called
27598
19:48:15,960 --> 19:48:16,960
on off-boarding so policy for hiring
27599
19:48:18,424 --> 19:48:19,424
people and then terminating this should
27600
19:48:20,872 --> 19:48:21,872
obviously go through the HR team as well
27601
19:48:22,920 --> 19:48:23,920
because the chances are if it's a big
27602
19:48:24,832 --> 19:48:25,832
company you may not know who's coming
27603
19:48:27,000 --> 19:48:28,000
who's gone and and obviously sometimes
27604
19:48:29,464 --> 19:48:30,464
people will give notice
27605
19:48:31,856 --> 19:48:32,856
and they're for um privacy or whatever
27606
19:48:35,160 --> 19:48:36,160
other reasons uh they're not allowed to
27607
19:48:37,920 --> 19:48:38,920
work at the company anymore they're
27608
19:48:39,536 --> 19:48:40,536
basically in in the UK it's called
27609
19:48:41,216 --> 19:48:42,216
gardening leave they're told to leave
27610
19:48:43,320 --> 19:48:44,320
immediately but they're paid for the
27611
19:48:45,240 --> 19:48:46,240
rest of their contract
27612
19:48:47,040 --> 19:48:48,040
what access and privilege levels they're
27613
19:48:49,016 --> 19:48:50,016
given and when are they given email
27614
19:48:51,176 --> 19:48:52,176
access and access to Shared directories
27615
19:48:53,824 --> 19:48:54,824
and files are they given best practice
27616
19:48:55,920 --> 19:48:56,920
training this is normally
27617
19:48:58,616 --> 19:48:59,616
um in the form of CBT and then they get
27618
19:49:01,504 --> 19:49:02,504
a certificate maybe and then that goes
27619
19:49:03,896 --> 19:49:04,896
off to the manager for filing
27620
19:49:06,176 --> 19:49:07,176
just to prove they've been shown what
27621
19:49:08,400 --> 19:49:09,400
they should and shouldn't do do they get
27622
19:49:10,440 --> 19:49:11,440
a smartphone another what are they
27623
19:49:12,480 --> 19:49:13,480
allowed to use this Smartphone for
27624
19:49:15,000 --> 19:49:16,000
uh licensing use of corporate hardware
27625
19:49:17,696 --> 19:49:18,696
and software and I remember when I
27626
19:49:19,800 --> 19:49:20,800
worked at a large company I won't say uh
27627
19:49:22,256 --> 19:49:23,256
who they had
27628
19:49:24,360 --> 19:49:25,360
um they had a few servers that we could
27629
19:49:26,640 --> 19:49:27,640
use for internal files but people would
27630
19:49:28,920 --> 19:49:29,920
download it was cracked software
27631
19:49:34,976 --> 19:49:35,976
crack software and it was video videos
27632
19:49:38,000 --> 19:49:39,000
exams and a whole bunch of other stuff
27633
19:49:40,144 --> 19:49:41,144
that technically should have been paid
27634
19:49:42,176 --> 19:49:43,176
for with um hard-earned dollars but um
27635
19:49:45,784 --> 19:49:46,784
it was all put on there for free now
27636
19:49:48,896 --> 19:49:49,896
the um I'm sure the man at the top
27637
19:49:51,176 --> 19:49:52,176
managers didn't know but some managers
27638
19:49:52,976 --> 19:49:53,976
knew what was going on and this is going
27639
19:49:54,832 --> 19:49:55,832
to leave your your company uh legally a
27640
19:49:57,360 --> 19:49:58,360
light bulb download and sharing policy
27641
19:50:00,320 --> 19:50:01,320
training with a sign off which I've
27642
19:50:02,336 --> 19:50:03,336
already mentioned mentioned could be
27643
19:50:04,336 --> 19:50:05,336
computer-based training end of training
27644
19:50:07,016 --> 19:50:08,016
exam I had to do all sorts of things
27645
19:50:09,176 --> 19:50:10,176
health and safety and harassment
27646
19:50:11,784 --> 19:50:12,784
all this kind of stuff when I worked
27647
19:50:13,856 --> 19:50:14,856
even when I was a contractor
27648
19:50:16,744 --> 19:50:17,744
International export certainly in terms
27649
19:50:19,616 --> 19:50:20,616
of hardware and software say for example
27650
19:50:22,016 --> 19:50:23,016
the USA
27651
19:50:24,176 --> 19:50:25,176
when they developed the um GPS software
27652
19:50:28,080 --> 19:50:29,080
the it was only allowed a thing within
27653
19:50:30,656 --> 19:50:31,656
something like 100 meters accuracy the
27654
19:50:33,784 --> 19:50:34,784
soft the software you they could drop a
27655
19:50:35,640 --> 19:50:36,640
bomb then within a window of a moving
27656
19:50:38,824 --> 19:50:39,824
car
27657
19:50:40,744 --> 19:50:41,744
um but um that was not allowed out to
27658
19:50:42,296 --> 19:50:43,296
the public and now it's I think it's in
27659
19:50:44,040 --> 19:50:45,040
in the range of around 10 meters the
27660
19:50:47,040 --> 19:50:48,040
other thing is obviously encrypted
27661
19:50:49,616 --> 19:50:50,616
software is uh restricted because
27662
19:50:53,216 --> 19:50:54,216
depending on the level of encryption
27663
19:50:55,144 --> 19:50:56,144
issues by uh for terrorist organizations
27664
19:50:58,040 --> 19:50:59,040
so if you buy any software say for
27665
19:51:02,512 --> 19:51:03,512
example for from Cisco if it's a high
27666
19:51:05,400 --> 19:51:06,400
level encryption you'll normally need
27667
19:51:07,192 --> 19:51:08,192
some sort of license uh you can get it
27668
19:51:09,720 --> 19:51:10,720
from the government or um you know just
27669
19:51:11,464 --> 19:51:12,464
to do your own research and see how your
27670
19:51:13,440 --> 19:51:14,440
government deals with it satellite
27671
19:51:15,424 --> 19:51:16,424
satellite technology and images that are
27672
19:51:18,744 --> 19:51:19,744
protected or sensitive
27673
19:51:21,296 --> 19:51:22,296
uh there could be Financial penalties or
27674
19:51:23,872 --> 19:51:24,872
you could be criminally liable for uh
27675
19:51:26,160 --> 19:51:27,160
what goes on so
27676
19:51:28,376 --> 19:51:29,376
just be careful data loss could be
27677
19:51:31,080 --> 19:51:32,080
accidental or malicious I've even heard
27678
19:51:33,784 --> 19:51:34,784
instances of and the talk about this
27679
19:51:37,680 --> 19:51:38,680
elsewhere but the word computer gets
27680
19:51:40,856 --> 19:51:41,856
decommissioned sent off for sale in a
27681
19:51:43,616 --> 19:51:44,616
shop somewhere and then somebody can see
27682
19:51:46,016 --> 19:51:47,016
all the data I've actually on um eBay I
27683
19:51:50,872 --> 19:51:51,872
bought a Cisco router I'll do this image
27684
19:51:53,216 --> 19:51:54,216
here bought a Cisco router I booted it
27685
19:51:55,920 --> 19:51:56,920
up and I had a load of um IP information
27686
19:51:59,120 --> 19:52:00,120
password information
27687
19:52:02,240 --> 19:52:03,240
usernames and this was for a large ISP
27688
19:52:08,216 --> 19:52:09,216
um an internationally known ISP so
27689
19:52:11,280 --> 19:52:12,280
heaven knows who was decommissioning
27690
19:52:12,896 --> 19:52:13,896
their equipment but it wasn't being done
27691
19:52:15,000 --> 19:52:16,000
very professionally
27692
19:52:17,160 --> 19:52:18,160
have a policy for your clients devices
27693
19:52:19,552 --> 19:52:20,552
your network devices and any storage
27694
19:52:21,480 --> 19:52:22,480
devices and there's normally
27695
19:52:24,176 --> 19:52:25,176
um software that you can wipe off hard
27696
19:52:26,464 --> 19:52:27,464
drives or sometimes they have to be
27697
19:52:27,896 --> 19:52:28,896
destroyed
27698
19:52:29,040 --> 19:52:30,040
identify what's most sensitive normally
27699
19:52:31,512 --> 19:52:32,512
addresses credit card information emails
27700
19:52:34,744 --> 19:52:35,744
make sure people are trained and review
27701
19:52:37,016 --> 19:52:38,016
the training
27702
19:52:39,120 --> 19:52:40,120
I've talked about remote access
27703
19:52:40,696 --> 19:52:41,696
equipment you need to also work out who
27704
19:52:44,216 --> 19:52:45,216
is allowed remote access this can be
27705
19:52:47,760 --> 19:52:48,760
um
27706
19:52:49,256 --> 19:52:50,256
this could be sales if they're on the
27707
19:52:51,536 --> 19:52:52,536
road it could be
27708
19:52:53,512 --> 19:52:54,512
um
27709
19:52:57,720 --> 19:52:58,720
Telly see
27710
19:53:01,464 --> 19:53:02,464
telecomuters
27711
19:53:03,424 --> 19:53:04,424
that kind of thing people who work from
27712
19:53:05,696 --> 19:53:06,696
home
27713
19:53:07,016 --> 19:53:08,016
what VPN software are they allowed to
27714
19:53:09,000 --> 19:53:10,000
use are they allowed through SSH
27715
19:53:11,336 --> 19:53:12,336
software or if they don't have a good
27716
19:53:14,640 --> 19:53:15,640
internet connection probably people
27717
19:53:16,552 --> 19:53:17,552
won't use modems anymore but
27718
19:53:19,080 --> 19:53:20,080
uh disable HTTP access I've talked about
27719
19:53:22,080 --> 19:53:23,080
this elsewhere https but when you have a
27720
19:53:25,976 --> 19:53:26,976
device a lot of the time you can put an
27721
19:53:27,480 --> 19:53:28,480
IP address into a browser and manage it
27722
19:53:31,256 --> 19:53:32,256
what's your favorite VPN client software
27723
19:53:33,784 --> 19:53:34,784
what are they allowed to download if
27724
19:53:35,872 --> 19:53:36,872
anything onto Works laptops
27725
19:53:38,512 --> 19:53:39,512
are they allowed the intranet what can
27726
19:53:40,976 --> 19:53:41,976
they see on the internet and where can
27727
19:53:42,296 --> 19:53:43,296
they access it from Works emails a big
27728
19:53:44,936 --> 19:53:45,936
one especially with the uh the latest
27729
19:53:46,976 --> 19:53:47,976
presidential campaign as you know
27730
19:53:49,800 --> 19:53:50,800
um one of the candidates was accused of
27731
19:53:52,320 --> 19:53:53,320
download insensitive email onto their
27732
19:53:54,424 --> 19:53:55,424
from The Works servers onto their home
27733
19:53:56,760 --> 19:53:57,760
servers
27734
19:53:59,512 --> 19:54:00,512
what happens when there's an incident
27735
19:54:01,192 --> 19:54:02,192
there should be a policy because some
27736
19:54:04,016 --> 19:54:05,016
places have worked people are blaming
27737
19:54:06,120 --> 19:54:07,120
each other finger pointing nobody knows
27738
19:54:08,464 --> 19:54:09,464
who's responsible for what so there
27739
19:54:10,800 --> 19:54:11,800
should be
27740
19:54:11,832 --> 19:54:12,832
written
27741
19:54:13,440 --> 19:54:14,440
procedures and also training so
27742
19:54:15,296 --> 19:54:16,296
everybody knows who's responsible and
27743
19:54:17,512 --> 19:54:18,512
what the procedure is for um escalating
27744
19:54:20,280 --> 19:54:21,280
it who gets called who gets paged
27745
19:54:23,640 --> 19:54:24,640
uh who are the stakeholders so um you
27746
19:54:27,480 --> 19:54:28,480
know your Chief technology officer your
27747
19:54:29,824 --> 19:54:30,824
network manager security manager all
27748
19:54:32,824 --> 19:54:33,824
these kind of people who are they
27749
19:54:33,896 --> 19:54:34,896
involved depending on what the problem
27750
19:54:35,280 --> 19:54:36,280
is
27751
19:54:36,480 --> 19:54:37,480
so identify the start procedures the
27752
19:54:39,000 --> 19:54:40,000
start the procedures and the steps that
27753
19:54:40,680 --> 19:54:41,680
take place you're normally work in some
27754
19:54:42,832 --> 19:54:43,832
sort of framework like
27755
19:54:44,936 --> 19:54:45,936
ITIL it infrastructure Library
27756
19:54:48,832 --> 19:54:49,832
they have qualifications on them
27757
19:54:50,760 --> 19:54:51,760
procedures you should be using
27758
19:54:52,856 --> 19:54:53,856
who declares it's an incident uh within
27759
19:54:55,800 --> 19:54:56,800
ITIL you've got um
27760
19:54:58,976 --> 19:54:59,976
you've got different streams problem
27761
19:55:05,400 --> 19:55:06,400
you've got the problem manager normally
27762
19:55:07,440 --> 19:55:08,440
on any team that's one person who
27763
19:55:10,440 --> 19:55:11,440
everyone reports a problem to
27764
19:55:13,144 --> 19:55:14,144
instead of basically everyone in the
27765
19:55:15,960 --> 19:55:16,960
team being told through help desk
27766
19:55:17,336 --> 19:55:18,336
tickets and then they tell other people
27767
19:55:19,504 --> 19:55:20,504
the problem manager will receive all of
27768
19:55:22,320 --> 19:55:23,320
the reports of the problems and then
27769
19:55:23,936 --> 19:55:24,936
they will escalate it when there's a
27770
19:55:25,856 --> 19:55:26,856
resolution it'll go through the problem
27771
19:55:27,656 --> 19:55:28,656
manager and they will communicate it
27772
19:55:29,640 --> 19:55:30,640
through group email phone calls or
27773
19:55:31,976 --> 19:55:32,976
whatever
27774
19:55:33,600 --> 19:55:34,600
uh can their damage be isolated
27775
19:55:36,656 --> 19:55:37,656
um can it be who's who's in charge of
27776
19:55:38,512 --> 19:55:39,512
actually removing it who will they speak
27777
19:55:40,616 --> 19:55:41,616
to can they um who's got the authority
27778
19:55:43,376 --> 19:55:44,376
to um to escalate it to say
27779
19:55:47,512 --> 19:55:48,512
um Cisco attack or um the AWS uh Senior
27780
19:55:52,616 --> 19:55:53,616
Team if you've got a support contract
27781
19:55:54,056 --> 19:55:55,056
with Amazon
27782
19:55:55,680 --> 19:55:56,680
uh then eventually hopefully it's
27783
19:55:57,480 --> 19:55:58,480
recovered Network restored to normal
27784
19:55:59,216 --> 19:56:00,216
function there'll be a debrief after if
27785
19:56:02,576 --> 19:56:03,576
you go through the idle procedures
27786
19:56:05,216 --> 19:56:06,216
there's a normally a meeting a
27787
19:56:07,616 --> 19:56:08,616
resolution and then something will
27788
19:56:09,000 --> 19:56:10,000
happen to
27789
19:56:10,920 --> 19:56:11,920
um change the procedures so it doesn't
27790
19:56:12,896 --> 19:56:13,896
happen again
27791
19:56:14,336 --> 19:56:15,336
the training or there could be some sort
27792
19:56:17,160 --> 19:56:18,160
of consequence if somebody's made a
27793
19:56:19,440 --> 19:56:20,440
mistake that they should have known
27794
19:56:20,464 --> 19:56:21,464
better
27795
19:56:21,600 --> 19:56:22,600
BYOD bring your own device normally and
27796
19:56:24,720 --> 19:56:25,720
not allowed in fact most places really
27797
19:56:27,360 --> 19:56:28,360
should have the USB ports disabled
27798
19:56:31,256 --> 19:56:32,256
um and decided who can use what where
27799
19:56:34,856 --> 19:56:35,856
the policy per device so for example
27800
19:56:38,160 --> 19:56:39,160
um can they bring a whap in probably not
27801
19:56:40,680 --> 19:56:41,680
could they bring a USB device in
27802
19:56:44,824 --> 19:56:45,824
even phones are they allowed to bring
27803
19:56:46,920 --> 19:56:47,920
phones in could they try and pig you
27804
19:56:48,536 --> 19:56:49,536
back onto the wireless network all these
27805
19:56:50,696 --> 19:56:51,696
kind of things there should be a policy
27806
19:56:52,016 --> 19:56:53,016
for
27807
19:56:54,056 --> 19:56:55,056
and who owns what data if somebody
27808
19:56:55,680 --> 19:56:56,680
brings in their device and but they're
27809
19:56:58,856 --> 19:56:59,856
using it for work you know who entered
27810
19:57:00,720 --> 19:57:01,720
data this all needs to be clear what
27811
19:57:02,640 --> 19:57:03,640
applications can they use
27812
19:57:04,680 --> 19:57:05,680
and what can be taken off-site as well
27813
19:57:06,832 --> 19:57:07,832
you need to decide what hardware and
27814
19:57:08,696 --> 19:57:09,696
software can be taken off site
27815
19:57:10,680 --> 19:57:11,680
the acceptable use policy uh stop and
27816
19:57:13,192 --> 19:57:14,192
search depends where you are and how
27817
19:57:15,536 --> 19:57:16,536
secure the site is but people can search
27818
19:57:17,336 --> 19:57:18,336
your bag
27819
19:57:18,720 --> 19:57:19,720
uh speaking of which I already mentioned
27820
19:57:20,936 --> 19:57:21,936
the acceptable use policy there should
27821
19:57:22,920 --> 19:57:23,920
be a security policy included
27822
19:57:25,256 --> 19:57:26,256
how the network should and shouldn't be
27823
19:57:27,360 --> 19:57:28,360
used what you're allowed to do it should
27824
19:57:28,856 --> 19:57:29,856
be clearly spelled out and signed
27825
19:57:30,424 --> 19:57:31,424
websites you can access I know when I
27826
19:57:33,120 --> 19:57:34,120
worked at this particular ISP
27827
19:57:36,720 --> 19:57:37,720
at the end of every month the manager
27828
19:57:38,936 --> 19:57:39,936
would per employee
27829
19:57:41,216 --> 19:57:42,216
they would have a list of every single
27830
19:57:43,144 --> 19:57:44,144
website you went to and how many minutes
27831
19:57:45,960 --> 19:57:46,960
you spent on the website so if you've
27832
19:57:48,720 --> 19:57:49,720
spent 60 Minutes on whatever say eBay
27833
19:57:51,784 --> 19:57:52,784
even though and we couldn't do it but
27834
19:57:53,400 --> 19:57:54,400
say you were found to be on eBay for 60
27835
19:57:55,144 --> 19:57:56,144
minutes then obviously there's going to
27836
19:57:57,424 --> 19:57:58,424
be a consequence you'd either be told
27837
19:57:58,800 --> 19:57:59,800
off written or an invariable warning or
27838
19:58:01,256 --> 19:58:02,256
you could be sacked
27839
19:58:03,600 --> 19:58:04,600
and what you can and can't download a
27840
19:58:06,480 --> 19:58:07,480
social media again this is a killer
27841
19:58:08,216 --> 19:58:09,216
you're not really being paid at work to
27842
19:58:10,320 --> 19:58:11,320
social media unless it's part of your
27843
19:58:12,000 --> 19:58:13,000
job for example digital marketing NDA as
27844
19:58:16,080 --> 19:58:17,080
well these are these are huge in the
27845
19:58:17,696 --> 19:58:18,696
corporate environment
27846
19:58:19,376 --> 19:58:20,376
protects non-public information so
27847
19:58:22,320 --> 19:58:23,320
you're you're learning about customers
27848
19:58:24,240 --> 19:58:25,240
names phone phone details uh who are the
27849
19:58:27,656 --> 19:58:28,656
key contacts all of this kind of
27850
19:58:29,104 --> 19:58:30,104
information what are the consequences of
27851
19:58:31,552 --> 19:58:32,552
the breach this could be
27852
19:58:33,960 --> 19:58:34,960
um Criminal
27853
19:58:37,376 --> 19:58:38,376
or it could be civil so you could have
27854
19:58:40,080 --> 19:58:41,080
to pay Financial penalties
27855
19:58:44,512 --> 19:58:45,512
and this creates a confidential
27856
19:58:45,960 --> 19:58:46,960
relationship between the disclosing
27857
19:58:48,176 --> 19:58:49,176
party
27858
19:58:49,256 --> 19:58:50,256
and the receiving party
27859
19:58:51,424 --> 19:58:52,424
your boss or your company and you which
27860
19:58:54,480 --> 19:58:55,480
is fair
27861
19:58:56,696 --> 19:58:57,696
uh the system life cycle which is asset
27862
19:58:59,280 --> 19:59:00,280
disposal something is brought into
27863
19:59:01,552 --> 19:59:02,552
um Commission
27864
19:59:04,256 --> 19:59:05,256
oh sorry I did this in a weird way so
27865
19:59:06,784 --> 19:59:07,784
integrate devices some something is
27866
19:59:08,696 --> 19:59:09,696
brought into the network and then it
27867
19:59:10,856 --> 19:59:11,856
would have to go through a chain of
27868
19:59:12,120 --> 19:59:13,120
events for example a router would all
27869
19:59:15,000 --> 19:59:16,000
have to be cabled up then it'd be passed
27870
19:59:17,216 --> 19:59:18,216
on to another team to do
27871
19:59:20,104 --> 19:59:21,104
um username and passwords for example
27872
19:59:22,800 --> 19:59:23,800
then it might go to the security team
27873
19:59:25,192 --> 19:59:26,192
for configuration
27874
19:59:27,176 --> 19:59:28,176
then it might go to the backup team to
27875
19:59:30,176 --> 19:59:31,176
make sure that it could and they can
27876
19:59:32,696 --> 19:59:33,696
download files and configurations and
27877
19:59:35,760 --> 19:59:36,760
recover it if there's a problem
27878
19:59:37,976 --> 19:59:38,976
and procedure to decommission what
27879
19:59:40,192 --> 19:59:41,192
happens uh does it go in the bin does it
27880
19:59:43,616 --> 19:59:44,616
go to a shop for sale
27881
19:59:46,320 --> 19:59:47,320
and as I've already said and if it's
27882
19:59:48,424 --> 19:59:49,424
going to go for sale then all the date
27883
19:59:49,744 --> 19:59:50,744
all the data needs to be removed hard
27884
19:59:52,744 --> 19:59:53,744
drives are they going to be scrubbed are
27885
19:59:54,176 --> 19:59:55,176
they going to be physically destroyed in
27886
19:59:56,464 --> 19:59:57,464
a furnace or some other device what are
27887
19:59:59,760 --> 20:00:00,760
the laws for recycling a lot of
27888
20:00:01,440 --> 20:00:02,440
countries now are really hot on and
27889
20:00:04,144 --> 20:00:05,144
non-recyclable stuff so if you can't
27890
20:00:06,000 --> 20:00:07,000
destroy it how are you going to render
27891
20:00:08,464 --> 20:00:09,464
it and usable or the data on it unusable
27892
20:00:11,640 --> 20:00:12,640
certainly
27893
20:00:13,800 --> 20:00:14,800
safety procedures
27894
20:00:16,144 --> 20:00:17,144
um
27895
20:00:18,896 --> 20:00:19,896
so who can troubleshoot the equipment
27896
20:00:20,896 --> 20:00:21,896
people need to know what air their job
27897
20:00:23,400 --> 20:00:24,400
is you could um
27898
20:00:25,680 --> 20:00:26,680
ignore that sorry authorized Personnel
27899
20:00:28,144 --> 20:00:29,144
who can cable stuff who's been trained
27900
20:00:30,360 --> 20:00:31,360
who's insured monitors as well certainly
27901
20:00:33,056 --> 20:00:34,056
the old cathode ray monitors there was
27902
20:00:35,872 --> 20:00:36,872
the back of them and the front
27903
20:00:38,400 --> 20:00:39,400
uh just massive things it would take two
27904
20:00:41,400 --> 20:00:42,400
people to carry them and they'd have a
27905
20:00:43,616 --> 20:00:44,616
massive electricity electrical current
27906
20:00:45,360 --> 20:00:46,360
going in through them as well even when
27907
20:00:47,760 --> 20:00:48,760
unplugged
27908
20:00:49,440 --> 20:00:50,440
um it still held a massive uh current
27909
20:00:52,376 --> 20:00:53,376
and could have shocked somebody or
27910
20:00:54,120 --> 20:00:55,120
killed them
27911
20:00:55,800 --> 20:00:56,800
who can move what uh heavy lifting so I
27912
20:00:59,280 --> 20:01:00,280
work for as I said an ISP and I work for
27913
20:01:02,512 --> 20:01:03,512
the network support team I remotely
27914
20:01:05,336 --> 20:01:06,336
accessed routers and switches firewalls
27915
20:01:08,872 --> 20:01:09,872
load balances and one day uh one of the
27916
20:01:12,176 --> 20:01:13,176
one of my bosses asked you know you've
27917
20:01:14,696 --> 20:01:15,696
got racks these big racks that are full
27918
20:01:16,856 --> 20:01:17,856
of really heavy equipment and some of it
27919
20:01:19,376 --> 20:01:20,376
can take up a half rack a massive Cisco
27920
20:01:21,480 --> 20:01:22,480
switch and he came and asked me if I
27921
20:01:23,872 --> 20:01:24,872
could remove one of the switches and put
27922
20:01:26,760 --> 20:01:27,760
a new one in now I wasn't actually there
27923
20:01:29,464 --> 20:01:30,464
for that this is down to the hardware
27924
20:01:31,256 --> 20:01:32,256
team at the time this stuff weighed
27925
20:01:34,320 --> 20:01:35,320
something likes
27926
20:01:36,480 --> 20:01:37,480
um
27927
20:01:37,320 --> 20:01:38,320
say 150 kilos and he was asking me to
27928
20:01:40,800 --> 20:01:41,800
somehow pull it out
27929
20:01:42,720 --> 20:01:43,720
put it somewhere and um put the new one
27930
20:01:45,656 --> 20:01:46,656
in I wasn't actually trained to install
27931
20:01:48,176 --> 20:01:49,176
this heavy equipment I I didn't have any
27932
20:01:50,464 --> 20:01:51,464
safety equipment I couldn't move it
27933
20:01:53,656 --> 20:01:54,656
and um maybe he just didn't care or he
27934
20:01:57,120 --> 20:01:58,120
was just ignorant but I had to turn
27935
20:01:58,376 --> 20:01:59,376
around and say well I'm not actually
27936
20:01:59,600 --> 20:02:00,600
qualified to move this equipment but I
27937
20:02:03,240 --> 20:02:04,240
am qualified to support it but I can
27938
20:02:06,240 --> 20:02:07,240
only connect to it over the network
27939
20:02:08,640 --> 20:02:09,640
um he wasn't very happy but it's better
27940
20:02:10,920 --> 20:02:11,920
than me breaking my leg or whatever is
27941
20:02:13,504 --> 20:02:14,504
there any safety equipment required
27942
20:02:15,656 --> 20:02:16,656
normally when you're installing heavy
27943
20:02:17,280 --> 20:02:18,280
stuff you need a hard hat
27944
20:02:19,976 --> 20:02:20,976
so you you need your hat you need your
27945
20:02:22,800 --> 20:02:23,800
boots uh you've you've got to have read
27946
20:02:25,144 --> 20:02:26,144
the training manuals
27947
20:02:27,536 --> 20:02:28,536
um are you insured and there's a whole
27948
20:02:30,296 --> 20:02:31,296
bunch of stuff yeah normally it would go
27949
20:02:32,400 --> 20:02:33,400
in a trolley again who's who can use
27950
20:02:34,920 --> 20:02:35,920
this trolley
27951
20:02:36,600 --> 20:02:37,600
uh electrical circuits certainly in many
27952
20:02:39,720 --> 20:02:40,720
countries for example Germany and
27953
20:02:41,216 --> 20:02:42,216
Australia you can't even change a plug
27954
20:02:43,800 --> 20:02:44,800
you have to be a qualified electrician
27955
20:02:46,800 --> 20:02:47,800
to access electronic equipment
27956
20:02:51,296 --> 20:02:52,296
all right so we've covered a lot of
27957
20:02:52,440 --> 20:02:53,440
stuff your user agreement your password
27958
20:02:54,536 --> 20:02:55,536
policy and the levels of password
27959
20:02:56,872 --> 20:02:57,872
leaving the company so joining leaving
27960
20:03:00,000 --> 20:03:01,000
the company any licensing uh export for
27961
20:03:04,680 --> 20:03:05,680
example security images and um
27962
20:03:07,976 --> 20:03:08,976
all this kind of stuff what's it
27963
20:03:09,720 --> 20:03:10,720
protected by and what you can explore
27964
20:03:11,280 --> 20:03:12,280
and import what happens to prevent data
27965
20:03:14,160 --> 20:03:15,160
loss of remote access
27966
20:03:16,320 --> 20:03:17,320
what happens was that when there's an
27967
20:03:17,872 --> 20:03:18,872
incident can you bring your own device
27968
20:03:20,040 --> 20:03:21,040
hopefully not
27969
20:03:21,784 --> 20:03:22,784
sign in the acceptable use policy
27970
20:03:24,656 --> 20:03:25,656
your non-disclosure
27971
20:03:26,576 --> 20:03:27,576
system life cycle and then finally
27972
20:03:28,680 --> 20:03:29,680
keeping keeping safe
27973
20:03:30,832 --> 20:03:31,832
that's all for now thanks for listening
27974
20:03:41,370 --> 20:03:42,370
[Music]
27975
20:03:45,616 --> 20:03:46,616
thank you
27976
20:03:52,464 --> 20:03:53,464
welcome to module 14 lesson 4 securing
27977
20:03:56,336 --> 20:03:57,336
the wireless network
27978
20:03:59,512 --> 20:04:00,512
a few things we want to cover syllabus
27979
20:04:01,440 --> 20:04:02,440
items uh WPA WPA2 tkip rc4
27980
20:04:07,680 --> 20:04:08,680
ccmp AES
27981
20:04:10,320 --> 20:04:11,320
EAP
27982
20:04:11,824 --> 20:04:12,824
lots of abbreviations gfn sync
27983
20:04:18,120 --> 20:04:19,120
if you've been using wireless routers
27984
20:04:19,976 --> 20:04:20,976
for any period of time you've probably
27985
20:04:21,600 --> 20:04:22,600
heard of WEP which was the first
27986
20:04:24,240 --> 20:04:25,240
protocol used
27987
20:04:26,824 --> 20:04:27,824
um to secure your wireless network it
27988
20:04:29,512 --> 20:04:30,512
was um it's pretty much better than
27989
20:04:31,256 --> 20:04:32,256
nothing I guess but it was flawed very
27990
20:04:34,856 --> 20:04:35,856
easily crackable and quite quickly after
27991
20:04:37,016 --> 20:04:38,016
it came out they realized they had to
27992
20:04:38,760 --> 20:04:39,760
upgrade it and replace it with something
27993
20:04:40,744 --> 20:04:41,744
better
27994
20:04:41,760 --> 20:04:42,760
and then it's upgraded uh replace with a
27995
20:04:45,360 --> 20:04:46,360
Wi-Fi protected access as you can see
27996
20:04:47,576 --> 20:04:48,576
the title at the top web is a wireless
27997
20:04:49,976 --> 20:04:50,976
equivalent privacy I think it stands for
27998
20:04:53,696 --> 20:04:54,696
from 2003 WPA was available it uses as a
27999
20:04:59,104 --> 20:05:00,104
dynamic key management and it's based on
28000
20:05:01,744 --> 20:05:02,744
EAP
28001
20:05:03,856 --> 20:05:04,856
WPA uses temporal key Integrity protocol
28002
20:05:07,440 --> 20:05:08,440
so I'm glad they do abbreviate it so
28003
20:05:10,016 --> 20:05:11,016
you've got something like 50 trillion
28004
20:05:11,576 --> 20:05:12,576
key compilations which is quite a lot
28005
20:05:14,824 --> 20:05:15,824
you can use it with radius in the
28006
20:05:16,856 --> 20:05:17,856
Enterprise we've talked about radius and
28007
20:05:18,720 --> 20:05:19,720
radius servers elsewhere in the course
28008
20:05:21,240 --> 20:05:22,240
so this basically offloads all of the
28009
20:05:23,872 --> 20:05:24,872
management and um
28010
20:05:26,216 --> 20:05:27,216
and authorization onto another device
28011
20:05:28,976 --> 20:05:29,976
that's um designed for that purpose
28012
20:05:32,336 --> 20:05:33,336
he uses an encrypted hash
28013
20:05:35,464 --> 20:05:36,464
each packet has a unique encryption key
28014
20:05:40,800 --> 20:05:41,800
a WPA2 is based on the 802.11i
28015
20:05:44,576 --> 20:05:45,576
architecture if you want to prove that
28016
20:05:47,040 --> 20:05:48,040
documentation it can integrate with ATO
28017
20:05:50,480 --> 20:05:51,480
2.1 x there is they do allude to this I
28018
20:05:53,872 --> 20:05:54,872
think in these syllabus actually and
28019
20:05:55,680 --> 20:05:56,680
it's a method of authentication and
28020
20:05:57,784 --> 20:05:58,784
authorization running on their layer 2
28021
20:06:00,600 --> 20:06:01,600
networks it's covered in quite some
28022
20:06:02,512 --> 20:06:03,512
detail in the Cisco CCNA actually
28023
20:06:06,000 --> 20:06:07,000
this allows users and devices to
28024
20:06:08,576 --> 20:06:09,576
authenticate with EAP plus it uses
28025
20:06:11,336 --> 20:06:12,336
tacaxa radius so just take a little bit
28026
20:06:14,336 --> 20:06:15,336
of setting up but you'll certainly find
28027
20:06:16,440 --> 20:06:17,440
this in Enterprise level Networks
28028
20:06:20,936 --> 20:06:21,936
the rc4 was replaced by Advanced
28029
20:06:23,936 --> 20:06:24,936
encryption standard AES this is 256 bits
28030
20:06:27,656 --> 20:06:28,656
as a minimum and Beyond
28031
20:06:30,600 --> 20:06:31,600
a TK IP was replaced by computer mode
28032
20:06:33,480 --> 20:06:34,480
with Cipher block chaining ccmp
28033
20:06:39,920 --> 20:06:40,920
uh and I've already mentioned uses uh
28034
20:06:42,720 --> 20:06:43,720
encrypted hash
28035
20:06:45,720 --> 20:06:46,720
each packet has a unique encryption key
28036
20:06:48,600 --> 20:06:49,600
um again I mentioned this earlier
28037
20:06:51,000 --> 20:06:52,000
MAC address filtering I've just found a
28038
20:06:54,056 --> 20:06:55,056
basic uh router here and even this cheap
28039
20:06:57,240 --> 20:06:58,240
one and looks like um maybe it Linksys
28040
20:06:59,872 --> 20:07:00,872
one at the looking at the colors you can
28041
20:07:02,640 --> 20:07:03,640
use their filtering enable prevents
28042
20:07:04,976 --> 20:07:05,976
clients
28043
20:07:06,176 --> 20:07:07,176
um listed from accessing the network if
28044
20:07:08,512 --> 20:07:09,512
you want to stop certain clients or you
28045
20:07:10,744 --> 20:07:11,744
can have a permit only list whereas you
28046
20:07:13,256 --> 20:07:14,256
manually and decide which packets go and
28047
20:07:16,616 --> 20:07:17,616
which Mac addresses are allowed
28048
20:07:20,640 --> 20:07:21,640
uh should be used with other security
28049
20:07:22,376 --> 20:07:23,376
features in case of Max spoofing and
28050
20:07:24,832 --> 20:07:25,832
it's quite easy certainly on devices
28051
20:07:26,464 --> 20:07:27,464
I've managed to log in and manually
28052
20:07:29,400 --> 20:07:30,400
change the MAC address of your device
28053
20:07:32,040 --> 20:07:33,040
and here's a permit list for just a
28054
20:07:35,640 --> 20:07:36,640
random device a random device I found
28055
20:07:40,616 --> 20:07:41,616
EAP extensible Authentication Protocol
28056
20:07:43,320 --> 20:07:44,320
it's a framework used in wireless
28057
20:07:45,120 --> 20:07:46,120
networks they've got an RFC for it if
28058
20:07:47,576 --> 20:07:48,576
you have the time to look
28059
20:07:49,744 --> 20:07:50,744
100 plus types available so I think
28060
20:07:52,920 --> 20:07:53,920
they're only list three or four in the
28061
20:07:54,240 --> 20:07:55,240
syllabus
28062
20:07:55,504 --> 20:07:56,504
EAP md5 uses a series of challenges and
28063
20:07:58,920 --> 20:07:59,920
responses
28064
20:08:00,360 --> 20:08:01,360
TLS this was designed by Microsoft and
28065
20:08:02,824 --> 20:08:03,824
uses a certificate system
28066
20:08:05,464 --> 20:08:06,464
fast is a designed by Cisco and it uses
28067
20:08:08,336 --> 20:08:09,336
a TLS tunnel with a secure socket layers
28068
20:08:12,056 --> 20:08:13,056
and on that node it also uses shared
28069
20:08:14,696 --> 20:08:15,696
secret Keys these are unique to each
28070
20:08:16,800 --> 20:08:17,800
user and they have protected access
28071
20:08:18,896 --> 20:08:19,896
credentials
28072
20:08:21,744 --> 20:08:22,744
ttls uses the secure TLS tunnel
28073
20:08:25,800 --> 20:08:26,800
and then finally this is also in a new
28074
20:08:28,320 --> 20:08:29,320
one in the syllabus uh PE AP increases
28075
20:08:31,552 --> 20:08:32,552
the protection of authentications by
28076
20:08:34,144 --> 20:08:35,144
creating a protected TLS tunnel
28077
20:08:38,104 --> 20:08:39,104
and within the tunnel on Authentication
28078
20:08:39,960 --> 20:08:40,960
Protocol such as Ms chat version 2 can
28079
20:08:43,504 --> 20:08:44,504
then be used
28080
20:08:46,824 --> 20:08:47,824
geofencing is a feature that is actually
28081
20:08:49,504 --> 20:08:50,504
built inside software so you don't
28082
20:08:51,240 --> 20:08:52,240
actually have it running on its own it
28083
20:08:54,296 --> 20:08:55,296
uses GPS or radio to Define geographical
28084
20:08:56,936 --> 20:08:57,936
boundaries I.E who's allowed in and out
28085
20:09:00,000 --> 20:09:01,000
of your network or device
28086
20:09:02,760 --> 20:09:03,760
uh triggers this default the triggers
28087
20:09:05,104 --> 20:09:06,104
defined for devices entering or exiting
28088
20:09:07,920 --> 20:09:08,920
the network boundaries
28089
20:09:10,496 --> 20:09:11,496
all right so just some of the we're
28090
20:09:12,120 --> 20:09:13,120
basically hitting some of the syllabus
28091
20:09:13,376 --> 20:09:14,376
items so this is why we went through
28092
20:09:15,000 --> 20:09:16,000
pretty quick uh WPA tkip
28093
20:09:19,576 --> 20:09:20,576
ccmp EAP and GF and Tim
28094
20:09:24,896 --> 20:09:25,896
okay that's all for now thanks for
28095
20:09:26,464 --> 20:09:27,464
watching
28096
20:09:30,200 --> 20:09:31,200
[Music]
28097
20:09:50,000 --> 20:09:51,000
Network Tools hardware troubleshooting
28098
20:09:53,640 --> 20:09:54,640
tools
28099
20:09:55,256 --> 20:09:56,256
in all the previous lessons we've talked
28100
20:09:57,720 --> 20:09:58,720
about a lot of different things and in
28101
20:09:59,576 --> 20:10:00,576
the very previous lesson we talked about
28102
20:10:00,896 --> 20:10:01,896
network security and how important it is
28103
20:10:02,936 --> 20:10:03,936
so in this final lesson I want to talk
28104
20:10:05,576 --> 20:10:06,576
briefly about some of the network tools
28105
20:10:08,216 --> 20:10:09,216
that were going to be useful when we're
28106
20:10:09,600 --> 20:10:10,600
running a network specifically in this
28107
20:10:12,176 --> 20:10:13,176
module about some of the troubleshooting
28108
20:10:14,040 --> 20:10:15,040
tools we're going to start off by
28109
20:10:16,320 --> 20:10:17,320
discussing the general top topic of
28110
20:10:19,504 --> 20:10:20,504
Hardware diagnosis and troubleshooting
28111
20:10:22,144 --> 20:10:23,144
and then we're going to move on to talk
28112
20:10:23,760 --> 20:10:24,760
about four common tools that are used in
28113
20:10:26,824 --> 20:10:27,824
troubleshooting software these are the
28114
20:10:29,936 --> 20:10:30,936
diagnostic disk multimeter cable testers
28115
20:10:33,600 --> 20:10:34,600
and a postcard there are of course other
28116
20:10:36,600 --> 20:10:37,600
tools however these are some of the
28117
20:10:38,872 --> 20:10:39,872
major ones that we want to know
28118
20:10:40,824 --> 20:10:41,824
specifically for this network plus exam
28119
20:10:45,240 --> 20:10:46,240
if you recall very early we talked about
28120
20:10:47,576 --> 20:10:48,576
some of the cable tools as well such as
28121
20:10:49,504 --> 20:10:50,504
toner probes and punch down tools and
28122
20:10:53,336 --> 20:10:54,336
those sort of fall into here but those
28123
20:10:55,744 --> 20:10:56,744
are more tools that we use to create
28124
20:10:57,424 --> 20:10:58,424
cables rather than ones that we're going
28125
20:10:59,400 --> 20:11:00,400
to do troubleshooting with
28126
20:11:01,192 --> 20:11:02,192
so we've briefly discussed Hardware in
28127
20:11:03,600 --> 20:11:04,600
the past but we need to take a closer
28128
20:11:05,104 --> 20:11:06,104
look at it for the sake of this module
28129
20:11:07,440 --> 20:11:08,440
Hardware is a term that refers to the
28130
20:11:10,192 --> 20:11:11,192
physical components of a computer system
28131
20:11:12,192 --> 20:11:13,192
including hard drives power supplies RAM
28132
20:11:14,872 --> 20:11:15,872
and other stuff Hardware unlike software
28133
20:11:17,464 --> 20:11:18,464
it's not a program it can't be installed
28134
20:11:19,744 --> 20:11:20,744
it can however be physically placed or
28135
20:11:22,320 --> 20:11:23,320
installed or changed in some cases but
28136
20:11:25,016 --> 20:11:26,016
this generally requires taking apart the
28137
20:11:26,696 --> 20:11:27,696
unit and physically installing something
28138
20:11:28,256 --> 20:11:29,256
new on it and when we're talking about a
28139
20:11:31,192 --> 20:11:32,192
computer I just want to point out that a
28140
20:11:32,936 --> 20:11:33,936
router a switch these are types of
28141
20:11:35,216 --> 20:11:36,216
computers a printer they do have
28142
20:11:37,320 --> 20:11:38,320
Hardware inside of them so important
28143
20:11:39,896 --> 20:11:40,896
that we realize this term is really
28144
20:11:41,464 --> 20:11:42,464
all-encompassing and because Hardware is
28145
20:11:44,640 --> 20:11:45,640
made up of physical components it
28146
20:11:47,216 --> 20:11:48,216
generally takes physical tools to
28147
20:11:48,960 --> 20:11:49,960
troubleshoot them by saying physical
28148
20:11:50,760 --> 20:11:51,760
tools this means tools that physically
28149
20:11:52,800 --> 20:11:53,800
come into contact with the hardware in
28150
20:11:55,376 --> 20:11:56,376
order to test it now some of the
28151
20:11:57,720 --> 20:11:58,720
hardware troubleshooting tools can
28152
20:11:59,280 --> 20:12:00,280
actually be programs that run on the
28153
20:12:00,896 --> 20:12:01,896
computer and one of those I'm going to
28154
20:12:02,936 --> 20:12:03,936
talk about in this module
28155
20:12:05,104 --> 20:12:06,104
so this non-physical troubleshooting
28156
20:12:08,280 --> 20:12:09,280
tool is commonly called a diagnostic or
28157
20:12:11,464 --> 20:12:12,464
diagnosis disk this is common software
28158
20:12:14,760 --> 20:12:15,760
that's used to test the system's
28159
20:12:16,680 --> 20:12:17,680
Hardware or in some cases the router's
28160
20:12:19,376 --> 20:12:20,376
hardware and so on it runs a series of
28161
20:12:21,784 --> 20:12:22,784
tests on different pieces of the
28162
20:12:23,464 --> 20:12:24,464
hardware in the system and if there are
28163
20:12:25,504 --> 20:12:26,504
issues that need to be fixed it'll
28164
20:12:27,000 --> 20:12:28,000
notify you you might be thinking if the
28165
20:12:29,216 --> 20:12:30,216
hardware of the computer is meant
28166
20:12:30,480 --> 20:12:31,480
malfunctioning how can you run a disk
28167
20:12:33,120 --> 20:12:34,120
well as long as the system's clock
28168
20:12:35,280 --> 20:12:36,280
circuits disk drive and CPU are
28169
20:12:38,336 --> 20:12:39,336
functioning diagnostic disk can be used
28170
20:12:41,040 --> 20:12:42,040
so again it does require CPU
28171
20:12:46,552 --> 20:12:47,552
the disk drive
28172
20:12:48,720 --> 20:12:49,720
or the USB contact whatever it is that
28173
20:12:52,440 --> 20:12:53,440
is going to
28174
20:12:54,600 --> 20:12:55,600
contain the disk or we should say
28175
20:12:57,176 --> 20:12:58,176
perhaps disk in some cases
28176
20:13:00,000 --> 20:13:01,000
and
28177
20:13:02,640 --> 20:13:03,640
clock circuits
28178
20:13:05,576 --> 20:13:06,576
which are the circuits that allow the
28179
20:13:07,504 --> 20:13:08,504
CPU to run
28180
20:13:09,240 --> 20:13:10,240
now I just made the C right here because
28181
20:13:11,160 --> 20:13:12,160
a disk with a K it's like a hard disk
28182
20:13:14,464 --> 20:13:15,464
like USB drives flash drives a disk with
28183
20:13:17,640 --> 20:13:18,640
a C
28184
20:13:19,144 --> 20:13:20,144
is Optical
28185
20:13:23,512 --> 20:13:24,512
now in general these disks aren't going
28186
20:13:26,464 --> 20:13:27,464
to State what the problem is they're
28187
20:13:29,040 --> 20:13:30,040
just going to say that there is
28188
20:13:30,240 --> 20:13:31,240
something malfunctioning and then it's
28189
20:13:31,920 --> 20:13:32,920
your job to actually take that
28190
20:13:33,536 --> 20:13:34,536
information and relate it into something
28191
20:13:35,640 --> 20:13:36,640
useful
28192
20:13:37,256 --> 20:13:38,256
they usually do this by producing a list
28193
20:13:39,832 --> 20:13:40,832
of all the different Hardware components
28194
20:13:42,120 --> 20:13:43,120
and basically saying which of them is
28195
20:13:43,920 --> 20:13:44,920
malfunctioning the course of action is
28196
20:13:46,144 --> 20:13:47,144
then up to whomever is going to
28197
20:13:47,696 --> 20:13:48,696
physically make repairs or test for more
28198
20:13:49,744 --> 20:13:50,744
this person is usually the administrator
28199
20:13:52,144 --> 20:13:53,144
or an I.T consultant or specifically
28200
20:13:54,896 --> 20:13:55,896
someone who's been sent out by the
28201
20:13:57,176 --> 20:13:58,176
manufacturer there are a number of tools
28202
20:13:59,160 --> 20:14:00,160
that they can use to diagnose once they
28203
20:14:01,552 --> 20:14:02,552
know what part is malfunctioning a
28204
20:14:04,440 --> 20:14:05,440
multimeter is one of the most common
28205
20:14:06,240 --> 20:14:07,240
tools that we see in the field of
28206
20:14:07,800 --> 20:14:08,800
electrical work and hardware
28207
20:14:09,360 --> 20:14:10,360
troubleshooting
28208
20:14:11,336 --> 20:14:12,336
it's used to test circuits outlets and
28209
20:14:14,400 --> 20:14:15,400
other electrical components of most
28210
20:14:16,144 --> 20:14:17,144
devices now there are very different
28211
20:14:18,120 --> 20:14:19,120
types of multimeters out there but they
28212
20:14:20,640 --> 20:14:21,640
all generally test for the same thing
28213
20:14:23,576 --> 20:14:24,576
they measure electrical current
28214
20:14:25,872 --> 20:14:26,872
resistance and wattage or voltage rather
28215
20:14:29,640 --> 20:14:30,640
current is generally going to be
28216
20:14:32,000 --> 20:14:33,000
measured in watts
28217
20:14:34,144 --> 20:14:35,144
resistance in ohms
28218
20:14:36,536 --> 20:14:37,536
and voltage
28219
20:14:39,120 --> 20:14:40,120
in volts
28220
20:14:40,496 --> 20:14:41,496
in the case of a hardware
28221
20:14:41,760 --> 20:14:42,760
troubleshooting the voltage and
28222
20:14:43,856 --> 20:14:44,856
resistance functions are actually going
28223
20:14:46,256 --> 20:14:47,256
to matter the most
28224
20:14:48,176 --> 20:14:49,176
may tell us information about say the
28225
20:14:51,000 --> 20:14:52,000
power supply or the wall socket that's
28226
20:14:54,536 --> 20:14:55,536
plugging into
28227
20:14:55,856 --> 20:14:56,856
now the only times that you're really
28228
20:14:57,720 --> 20:14:58,720
going to see or use a Multimeter
28229
20:15:01,320 --> 20:15:02,320
to be helpful for troubleshooting is
28230
20:15:02,936 --> 20:15:03,936
when we're talking about power supplies
28231
20:15:04,824 --> 20:15:05,824
and fuses which are also related
28232
20:15:09,120 --> 20:15:10,120
anything that has to do directly with
28233
20:15:10,920 --> 20:15:11,920
the electrical on the OSI model what
28234
20:15:13,192 --> 20:15:14,192
we're looking at here is layer one the
28235
20:15:15,536 --> 20:15:16,536
physical layer
28236
20:15:17,216 --> 20:15:18,216
voltage tests are important because they
28237
20:15:19,376 --> 20:15:20,376
can see if the power supply of a
28238
20:15:21,656 --> 20:15:22,656
computer or device is actually receiving
28239
20:15:23,640 --> 20:15:24,640
power the multimeter shows there's no
28240
20:15:25,856 --> 20:15:26,856
voltage and the power supply is probably
28241
20:15:28,016 --> 20:15:29,016
malfunctioning the resistance function
28242
20:15:30,424 --> 20:15:31,424
is used to test fuses if the fuse is
28243
20:15:33,176 --> 20:15:34,176
blown or faulty needs to be replaced the
28244
20:15:35,512 --> 20:15:36,512
multimeter is going to tell us this by
28245
20:15:37,376 --> 20:15:38,376
the resistance
28246
20:15:39,120 --> 20:15:40,120
so this is sort of what a multimeter
28247
20:15:42,176 --> 20:15:43,176
looks like this one would be considered
28248
20:15:44,464 --> 20:15:45,464
analog because you can see right here it
28249
20:15:47,464 --> 20:15:48,464
has a
28250
20:15:49,576 --> 20:15:50,576
basically a doesn't have a digital
28251
20:15:52,160 --> 20:15:53,160
output it's going to measure it with
28252
20:15:54,656 --> 20:15:55,656
this
28253
20:15:55,856 --> 20:15:56,856
um arm here that will move and then you
28254
20:15:58,496 --> 20:15:59,496
can read it based on the numbers that
28255
20:16:00,360 --> 20:16:01,360
are above there are as well digital
28256
20:16:03,080 --> 20:16:04,080
multimeters but either way they're all
28257
20:16:06,424 --> 20:16:07,424
going to have two probes which are
28258
20:16:08,464 --> 20:16:09,464
generally black and red the black road
28259
20:16:11,000 --> 20:16:12,000
probe rather is usually either for the
28260
20:16:13,552 --> 20:16:14,552
ground or the negative
28261
20:16:16,320 --> 20:16:17,320
and the red just like on your car is
28262
20:16:18,832 --> 20:16:19,832
going to be
28263
20:16:20,640 --> 20:16:21,640
for positive the dial in the middle is
28264
20:16:24,424 --> 20:16:25,424
going to be to test to determine what
28265
20:16:27,056 --> 20:16:28,056
you're going to test for are you going
28266
20:16:28,920 --> 20:16:29,920
to test your voltage are you going to
28267
20:16:30,720 --> 20:16:31,720
test for ohms are you going to test for
28268
20:16:33,600 --> 20:16:34,600
wattage etc etc
28269
20:16:36,296 --> 20:16:37,296
by the way the reason it's called a
28270
20:16:38,104 --> 20:16:39,104
multimeter is because it has a volt
28271
20:16:41,104 --> 20:16:42,104
meter in it
28272
20:16:42,960 --> 20:16:43,960
it has a
28273
20:16:45,240 --> 20:16:46,240
ohm meter in it Etc
28274
20:16:48,600 --> 20:16:49,600
so we combine all of these into one
28275
20:16:51,056 --> 20:16:52,056
device which is called a multimeter this
28276
20:16:53,216 --> 20:16:54,216
probably looks familiar if you have
28277
20:16:55,680 --> 20:16:56,680
already taken the a plus exam
28278
20:16:57,960 --> 20:16:58,960
now out of all the hardware failures
28279
20:16:59,872 --> 20:17:00,872
that can happen the one that's most
28280
20:17:01,192 --> 20:17:02,192
common has the biggest effect on the
28281
20:17:02,936 --> 20:17:03,936
network is cable failure this type of
28282
20:17:05,400 --> 20:17:06,400
thing happens all the time and there are
28283
20:17:06,784 --> 20:17:07,784
tools that are created to help with this
28284
20:17:08,512 --> 20:17:09,512
problem
28285
20:17:09,360 --> 20:17:10,360
cable testers are generally hand held
28286
20:17:12,480 --> 20:17:13,480
devices that are meant to test cable
28287
20:17:15,120 --> 20:17:16,120
connectivity they test to make sure that
28288
20:17:17,872 --> 20:17:18,872
the data is being communicated through
28289
20:17:19,744 --> 20:17:20,744
these cables properly
28290
20:17:22,080 --> 20:17:23,080
and there are a few main types of cable
28291
20:17:24,896 --> 20:17:25,896
testers
28292
20:17:26,120 --> 20:17:27,120
continuity testers are the least
28293
20:17:28,800 --> 20:17:29,800
expensive kind and all they do is test
28294
20:17:31,552 --> 20:17:32,552
for a broken cable basically they tell
28295
20:17:34,192 --> 20:17:35,192
you if there is continuity in the line
28296
20:17:37,504 --> 20:17:38,504
data cabling testers are a bit more
28297
20:17:40,376 --> 20:17:41,376
expensive they can actually test broken
28298
20:17:42,720 --> 20:17:43,720
cables and properly Twisted cables
28299
20:17:45,120 --> 20:17:46,120
shorted connections and more they'll
28300
20:17:47,696 --> 20:17:48,696
tell you what pins within the cable
28301
20:17:52,144 --> 20:17:53,144
are faulty
28302
20:17:56,040 --> 20:17:57,040
finally there are things called time
28303
20:17:58,016 --> 20:17:59,016
domain reflectors or tdrs they're the
28304
20:18:01,016 --> 20:18:02,016
most expensive out of the three so as we
28305
20:18:04,376 --> 20:18:05,376
move we're going from
28306
20:18:06,480 --> 20:18:07,480
less
28307
20:18:09,240 --> 20:18:10,240
to more they test exactly where a break
28308
20:18:12,000 --> 20:18:13,000
or issue is and the cable can be found
28309
20:18:14,160 --> 20:18:15,160
so they do this by sending basically out
28310
20:18:16,192 --> 20:18:17,192
a signal and they wait to see how long
28311
20:18:18,480 --> 20:18:19,480
that signal if I have a signal
28312
20:18:21,600 --> 20:18:22,600
let's say we make a little chord here
28313
20:18:24,720 --> 20:18:25,720
and I have my time domain reflector
28314
20:18:26,760 --> 20:18:27,760
connected over here it's going to send a
28315
20:18:29,216 --> 20:18:30,216
signal out
28316
20:18:30,536 --> 20:18:31,536
and it's going to wait and see
28317
20:18:35,280 --> 20:18:36,280
how long it takes before it's reflected
28318
20:18:37,744 --> 20:18:38,744
back
28319
20:18:40,744 --> 20:18:41,744
then they convert this time into a
28320
20:18:42,720 --> 20:18:43,720
distance so they know how far along the
28321
20:18:45,056 --> 20:18:46,056
cable error was found this way they can
28322
20:18:47,280 --> 20:18:48,280
literally tell us where
28323
20:18:49,800 --> 20:18:50,800
the problem took place and help us fix
28324
20:18:52,496 --> 20:18:53,496
the problem at its source as opposed to
28325
20:18:54,896 --> 20:18:55,896
us having to sort of try to find this
28326
20:18:57,056 --> 20:18:58,056
blindly the last thing I want to talk
28327
20:18:59,936 --> 20:19:00,936
about we talked about this in a plus as
28328
20:19:01,680 --> 20:19:02,680
well is postcards post stands for power
28329
20:19:05,696 --> 20:19:06,696
on
28330
20:19:07,016 --> 20:19:08,016
self-test and you might remember this
28331
20:19:09,536 --> 20:19:10,536
from the beep that you get at the very
28332
20:19:11,512 --> 20:19:12,512
beginning when your computer starts up
28333
20:19:14,040 --> 20:19:15,040
this card is inserted into a slot of a
28334
20:19:17,464 --> 20:19:18,464
device and it can tell us what is not
28335
20:19:21,056 --> 20:19:22,056
working in the in the system by giving
28336
20:19:24,424 --> 20:19:25,424
us generally a sort of code called a
28337
20:19:28,496 --> 20:19:29,496
postcode sometimes this is a beep code
28338
20:19:31,976 --> 20:19:32,976
as well
28339
20:19:33,120 --> 20:19:34,120
generally speaking you have to relate
28340
20:19:35,576 --> 20:19:36,576
the code to a manual to figure out what
28341
20:19:39,600 --> 20:19:40,600
it's telling us
28342
20:19:41,216 --> 20:19:42,216
these cards are really beneficial
28343
20:19:42,896 --> 20:19:43,896
because they allow us to test a
28344
20:19:45,056 --> 20:19:46,056
non-starting system without having to
28345
20:19:47,400 --> 20:19:48,400
start from scratch and restore the
28346
20:19:48,960 --> 20:19:49,960
entire thing in other words they can
28347
20:19:51,000 --> 20:19:52,000
test the system that would otherwise
28348
20:19:52,800 --> 20:19:53,800
have to be restored to a previous
28349
20:19:54,600 --> 20:19:55,600
version or which we'd have to rebuild so
28350
20:19:57,832 --> 20:19:58,832
the cards run the tests while the system
28351
20:19:59,824 --> 20:20:00,824
is attempting to start up and gives us
28352
20:20:02,336 --> 20:20:03,336
this beep code or this error code
28353
20:20:05,280 --> 20:20:06,280
then we can go to the code
28354
20:20:07,744 --> 20:20:08,744
look at a list and determine where the
28355
20:20:09,784 --> 20:20:10,784
problem is for instance perhaps the ram
28356
20:20:11,824 --> 20:20:12,824
is bad or is not just not seated
28357
20:20:14,464 --> 20:20:15,464
properly or perhaps it's not able to
28358
20:20:16,320 --> 20:20:17,320
find its firmware
28359
20:20:18,960 --> 20:20:19,960
so just to recap we talked about
28360
20:20:20,696 --> 20:20:21,696
hardware troubleshooting again Hardware
28361
20:20:22,616 --> 20:20:23,616
is the hard stuff not software we
28362
20:20:25,616 --> 20:20:26,616
physically have to deal with it and some
28363
20:20:28,016 --> 20:20:29,016
of the common tools we looked at were a
28364
20:20:29,872 --> 20:20:30,872
diagnostic disk which generally is just
28365
20:20:32,464 --> 20:20:33,464
going to tell us which item
28366
20:20:37,800 --> 20:20:38,800
is malfunctioning
28367
20:20:41,760 --> 20:20:42,760
and remember a diagnostic disk is in
28368
20:20:44,336 --> 20:20:45,336
effect
28369
20:20:46,440 --> 20:20:47,440
piece of software
28370
20:20:48,600 --> 20:20:49,600
we also looked at a multimeter
28371
20:20:51,120 --> 20:20:52,120
which is for electrical things this is
28372
20:20:54,960 --> 20:20:55,960
going to test volts
28373
20:20:57,360 --> 20:20:58,360
resistance
28374
20:21:00,120 --> 20:21:01,120
and current
28375
20:21:04,800 --> 20:21:05,800
faults and resistance are perhaps the
28376
20:21:07,192 --> 20:21:08,192
most important ones resistance for fuses
28377
20:21:09,720 --> 20:21:10,720
or Breakers
28378
20:21:11,216 --> 20:21:12,216
Volts for power supplies
28379
20:21:15,896 --> 20:21:16,896
we also looked at cable testers remember
28380
20:21:18,296 --> 20:21:19,296
there are three different ones that we
28381
20:21:19,680 --> 20:21:20,680
looked at continuity testers are just
28382
20:21:22,744 --> 20:21:23,744
going to tell us whether or not the
28383
20:21:23,936 --> 20:21:24,936
cable works
28384
20:21:25,856 --> 20:21:26,856
cabling testers
28385
20:21:28,144 --> 20:21:29,144
otherwise known as data cabling testers
28386
20:21:30,536 --> 20:21:31,536
will tell us actually which pins aren't
28387
20:21:33,424 --> 20:21:34,424
working
28388
20:21:34,616 --> 20:21:35,616
and
28389
20:21:36,176 --> 20:21:37,176
time domain reflectometers
28390
20:21:40,800 --> 20:21:41,800
let me write that out
28391
20:21:49,800 --> 20:21:50,800
will tell us where
28392
20:21:54,176 --> 20:21:55,176
the error is occurring
28393
20:21:56,040 --> 20:21:57,040
finally we have our postcard remember
28394
20:21:58,080 --> 20:21:59,080
post stands for power on
28395
20:22:01,856 --> 20:22:02,856
self
28396
20:22:03,424 --> 20:22:04,424
test
28397
20:22:04,920 --> 20:22:05,920
and this is going to tell us in a
28398
20:22:07,192 --> 20:22:08,192
non-functioning
28399
20:22:10,856 --> 20:22:11,856
or non-starting system
28400
20:22:17,464 --> 20:22:18,464
where the error is
28401
20:22:22,616 --> 20:22:23,616
it's very much like a diagnostic disc
28402
20:22:24,960 --> 20:22:25,960
however the diagnostic disc does
28403
20:22:28,856 --> 20:22:29,856
require the CPU
28404
20:22:31,976 --> 20:22:32,976
clock
28405
20:22:33,360 --> 20:22:34,360
and the disk interface
28406
20:22:39,120 --> 20:22:40,120
is functioning the postcard it's
28407
20:22:41,696 --> 20:22:42,696
literally a card we insert and it'll
28408
20:22:44,040 --> 20:22:45,040
tell us itself it does this again by
28409
20:22:46,496 --> 20:22:47,496
giving us a code that we can then
28410
20:22:48,784 --> 20:22:49,784
reference on a list
28411
20:22:54,060 --> 20:22:55,060
[Music]
28412
20:23:09,856 --> 20:23:10,856
welcome to module 15 lesson 1A physical
28413
20:23:13,144 --> 20:23:14,144
testing tools just updated the uh from
28414
20:23:18,720 --> 20:23:19,720
the last presentation really there's a
28415
20:23:20,464 --> 20:23:21,464
few extra little things slipped into the
28416
20:23:23,280 --> 20:23:24,280
syllabus which I I think is important to
28417
20:23:25,800 --> 20:23:26,800
cover
28418
20:23:26,824 --> 20:23:27,824
the cable crimper the punch down Tool
28419
20:23:29,104 --> 20:23:30,104
The Wire Strippers
28420
20:23:30,656 --> 20:23:31,656
otdr cable certifier we may have
28421
20:23:33,600 --> 20:23:34,600
actually mentioned these in other areas
28422
20:23:35,512 --> 20:23:36,512
of the presentation but I just wanted to
28423
20:23:38,280 --> 20:23:39,280
specifically address each one
28424
20:23:42,176 --> 20:23:43,176
cable crimpa also known as a y crimp hat
28425
20:23:45,000 --> 20:23:46,000
you'll be familiar with this tool if
28426
20:23:47,336 --> 20:23:48,336
you've created your own cables a lot of
28427
20:23:49,144 --> 20:23:50,144
people do at home just to save money
28428
20:23:51,120 --> 20:23:52,120
because they're so expensive if you buy
28429
20:23:52,920 --> 20:23:53,920
them from the electronic shops for some
28430
20:23:55,976 --> 20:23:56,976
reason
28431
20:23:57,000 --> 20:23:58,000
and also if for any reason something
28432
20:24:00,120 --> 20:24:01,120
goes wrong with the end of one of your
28433
20:24:01,680 --> 20:24:02,680
cables you could just snip off the end
28434
20:24:04,920 --> 20:24:05,920
and just um create your own
28435
20:24:07,256 --> 20:24:08,256
a cable it's fairly easy to do well with
28436
20:24:10,552 --> 20:24:11,552
a little bit of practice like anything
28437
20:24:12,192 --> 20:24:13,192
so you'll need a cable crimpo which you
28438
20:24:14,824 --> 20:24:15,824
also buy from the electronic shop use to
28439
20:24:17,336 --> 20:24:18,336
connect the end of a cable to a
28440
20:24:18,960 --> 20:24:19,960
connector it can depending on which one
28441
20:24:21,784 --> 20:24:22,784
you buy you can actually strip the cable
28442
20:24:23,464 --> 20:24:24,464
you separate the wires and then you can
28443
20:24:27,536 --> 20:24:28,536
um insert into inside here the
28444
20:24:31,376 --> 20:24:32,376
connector the plastic connector pop the
28445
20:24:34,256 --> 20:24:35,256
ends of the cable in which you've also
28446
20:24:36,536 --> 20:24:37,536
stripped With a Stripper and uh and then
28447
20:24:39,536 --> 20:24:40,536
clamp it closed and that clamps down on
28448
20:24:41,464 --> 20:24:42,464
the wires in the correct door down
28449
20:24:43,440 --> 20:24:44,440
different types of cable crimples for
28450
20:24:45,424 --> 20:24:46,424
different connectors
28451
20:24:47,936 --> 20:24:48,936
the punch down tool is known as a chrome
28452
20:24:50,760 --> 20:24:51,760
tool also used to connect wires into
28453
20:24:54,536 --> 20:24:55,536
punch down blocks
28454
20:25:01,192 --> 20:25:02,192
it strips off the insulation on The Wire
28455
20:25:03,784 --> 20:25:04,784
before inserting it into a punch block
28456
20:25:06,240 --> 20:25:07,240
not something I've used before because I
28457
20:25:08,512 --> 20:25:09,512
didn't
28458
20:25:09,176 --> 20:25:10,176
um
28459
20:25:09,720 --> 20:25:10,720
didn't use any of the punch down blocks
28460
20:25:12,552 --> 20:25:13,552
uh I did some cabling but didn't use a
28461
20:25:15,480 --> 20:25:16,480
punch down
28462
20:25:16,552 --> 20:25:17,552
not something I was interested in wire
28463
20:25:18,536 --> 20:25:19,536
strippers used to remove electrical
28464
20:25:20,824 --> 20:25:21,824
insulation from my wire on this
28465
20:25:22,920 --> 20:25:23,920
particular figure you can see the
28466
20:25:24,480 --> 20:25:25,480
difference and sizes
28467
20:25:26,824 --> 20:25:27,824
so you choose the correct size for the
28468
20:25:28,856 --> 20:25:29,856
cable type and that strips out the
28469
20:25:31,680 --> 20:25:32,680
um housing of the wire the plastic
28470
20:25:33,296 --> 20:25:34,296
covering and exposes the actual cable
28471
20:25:36,480 --> 20:25:37,480
itself
28472
20:25:38,160 --> 20:25:39,160
it has a center notch
28473
20:25:41,160 --> 20:25:42,160
otdr this stands for optical time domain
28474
20:25:44,176 --> 20:25:45,176
reflectometer I'm not saying that again
28475
20:25:46,192 --> 20:25:47,192
used to locate faults on networking
28476
20:25:48,536 --> 20:25:49,536
cable
28477
20:25:49,552 --> 20:25:50,552
I mean there's a argument that you if
28478
20:25:51,536 --> 20:25:52,536
you just think there's a fault in a
28479
20:25:52,800 --> 20:25:53,800
cable you just swap it out anyway it'd
28480
20:25:55,016 --> 20:25:56,016
be cheaper but it's available tool
28481
20:25:56,760 --> 20:25:57,760
anyway it sends light into the fiber and
28482
20:25:59,512 --> 20:26:00,512
based on the quality of the reflected
28483
20:26:00,896 --> 20:26:01,896
light it can determine the following
28484
20:26:03,240 --> 20:26:04,240
thought location length of the cable
28485
20:26:05,176 --> 20:26:06,176
loss of signal if applicable
28486
20:26:08,640 --> 20:26:09,640
a cable certifier it's used to carry out
28487
20:26:11,640 --> 20:26:12,640
tests it can test the following
28488
20:26:13,144 --> 20:26:14,144
conductors in the ethernet cable
28489
20:26:15,440 --> 20:26:16,440
continuity in the wires proper pairing
28490
20:26:18,480 --> 20:26:19,480
of the wires as well it's quite handy
28491
20:26:19,976 --> 20:26:20,976
you just plug it in
28492
20:26:21,360 --> 20:26:22,360
and it will give you lots of different
28493
20:26:22,744 --> 20:26:23,744
reading depending on the model you have
28494
20:26:24,480 --> 20:26:25,480
and how much you've spent
28495
20:26:26,216 --> 20:26:27,216
proper termination of cat cables
28496
20:26:29,640 --> 20:26:30,640
so they're covered in the syllabus which
28497
20:26:32,040 --> 20:26:33,040
is why I give them specific slide each
28498
20:26:34,552 --> 20:26:35,552
instead of just mentioning them in
28499
20:26:36,296 --> 20:26:37,296
passing as we may have done elsewhere so
28500
20:26:38,280 --> 20:26:39,280
the cable crimp are the punch down Tool
28501
20:26:40,192 --> 20:26:41,192
The Wire Strippers otdr cable certifier
28502
20:26:43,320 --> 20:26:44,320
all right so that's all thanks for
28503
20:26:45,424 --> 20:26:46,424
watching
28504
20:26:49,580 --> 20:26:50,580
[Music]
28505
20:26:58,824 --> 20:26:59,824
thank you
28506
20:27:05,960 --> 20:27:06,960
welcome to module 15 a lesson 1B
28507
20:27:09,616 --> 20:27:10,616
software testing tools
28508
20:27:13,552 --> 20:27:14,552
I'm not going to cover stuff that has
28509
20:27:15,056 --> 20:27:16,056
already been covered unless there's a
28510
20:27:16,440 --> 20:27:17,440
new point
28511
20:27:17,640 --> 20:27:18,640
or some of the reason for doing it
28512
20:27:19,920 --> 20:27:20,920
uh packet sniffers
28513
20:27:21,832 --> 20:27:22,832
Wi-Fi analyzer bandwidth speed tester
28514
20:27:25,824 --> 20:27:26,824
CLI tools command line tools uh not
28515
20:27:30,240 --> 20:27:31,240
already covered because of the way the
28516
20:27:32,104 --> 20:27:33,104
syllabus is set out we have to cover
28517
20:27:33,600 --> 20:27:34,600
some stuff earlier in later and in the
28518
20:27:35,576 --> 20:27:36,576
middle because it's relevant to that
28519
20:27:37,552 --> 20:27:38,552
particular subject for example security
28520
20:27:39,680 --> 20:27:40,680
or troubleshooting
28521
20:27:43,016 --> 20:27:44,016
I put an image here for Wireshark
28522
20:27:46,552 --> 20:27:47,552
um Wireshark I'm going to say a must no
28523
20:27:51,960 --> 20:27:52,960
missed
28524
20:27:55,744 --> 20:27:56,744
now you must know sniffing and uh
28525
20:27:58,320 --> 20:27:59,320
Wireshark is just the industry leader
28526
20:28:00,296 --> 20:28:01,296
and the good news is it's free to
28527
20:28:03,120 --> 20:28:04,120
download you could have a virtual
28528
20:28:05,400 --> 20:28:06,400
Network on my Cisco virtual rack which
28529
20:28:09,240 --> 20:28:10,240
is free on howturnetwork.com it actually
28530
20:28:12,176 --> 20:28:13,176
you booted up you've got to find your
28531
20:28:13,920 --> 20:28:14,920
own Cisco image because Cisco don't give
28532
20:28:16,144 --> 20:28:17,144
them away but I wonder why sharks you
28533
20:28:18,424 --> 20:28:19,424
can actually see traffic live passing
28534
20:28:20,872 --> 20:28:21,872
between your routers and other devices
28535
20:28:23,424 --> 20:28:24,424
this is an essential tool and you need
28536
20:28:26,464 --> 20:28:27,464
to understand it for troubleshooting
28537
20:28:30,144 --> 20:28:31,144
so uh really important you can see all
28538
20:28:33,296 --> 20:28:34,296
your protocols and packets and all that
28539
20:28:35,696 --> 20:28:36,696
kind of stuff so
28540
20:28:37,744 --> 20:28:38,744
um you'd you'd normally load this uh
28541
20:28:40,320 --> 20:28:41,320
software
28542
20:28:41,872 --> 20:28:42,872
all right the Wireshark it'd be loaded
28543
20:28:44,104 --> 20:28:45,104
onto your laptop if you're
28544
20:28:45,960 --> 20:28:46,960
troubleshooting you would leave it
28545
20:28:47,400 --> 20:28:48,400
running say for example you'd leave it
28546
20:28:49,920 --> 20:28:50,920
running for an hour
28547
20:28:51,832 --> 20:28:52,832
and and then you could analyze the
28548
20:28:54,176 --> 20:28:55,176
output
28549
20:28:55,552 --> 20:28:56,552
and see where a particular problems
28550
20:28:57,600 --> 20:28:58,600
happening is it is it happening for the
28551
20:29:00,296 --> 20:29:01,296
the whole hour is there some sort of
28552
20:29:03,176 --> 20:29:04,176
um
28553
20:29:04,016 --> 20:29:05,016
issue spikes and then or does the issue
28554
20:29:07,616 --> 20:29:08,616
sort of happen over this period of time
28555
20:29:09,480 --> 20:29:10,480
that kind of thing so the traffic is
28556
20:29:12,536 --> 20:29:13,536
going into your switch from the server
28557
20:29:14,336 --> 20:29:15,336
and you will configure
28558
20:29:17,104 --> 20:29:18,104
um the switch over here you would do a
28559
20:29:18,832 --> 20:29:19,832
configuration command on the switch to
28560
20:29:20,824 --> 20:29:21,824
send the traffic out on whichever Port
28561
20:29:23,216 --> 20:29:24,216
you've connected your laptop to
28562
20:29:26,040 --> 20:29:27,040
um you've just got to be aware of I'm
28563
20:29:28,744 --> 20:29:29,744
just telling you this because of the
28564
20:29:30,176 --> 20:29:31,176
real world you've got to be aware of CPU
28565
20:29:32,400 --> 20:29:33,400
and you've got to make sure that you get
28566
20:29:33,896 --> 20:29:34,896
permission off whoever the
28567
20:29:36,480 --> 20:29:37,480
um person in charge is when I've worked
28568
20:29:39,176 --> 20:29:40,176
on network teams and
28569
20:29:40,856 --> 20:29:41,856
um I knew the procedures and policies
28570
20:29:43,016 --> 20:29:44,016
which we've already talked about what I
28571
20:29:45,176 --> 20:29:46,176
can and can't do but if it could be
28572
20:29:47,464 --> 20:29:48,464
Network effect in for example the CPU
28573
20:29:50,464 --> 20:29:51,464
then you've got to make sure it is done
28574
20:29:53,696 --> 20:29:54,696
out of hours or you've got permission
28575
20:29:56,872 --> 20:29:57,872
so you'll check for traffic patterns of
28576
20:29:58,800 --> 20:29:59,800
Base a traffic Baseline any
28577
20:30:00,296 --> 20:30:01,296
irregularities they will pop up
28578
20:30:03,120 --> 20:30:04,120
you'll be mirroring a port
28579
20:30:05,760 --> 20:30:06,760
just be aware the package slippers can
28580
20:30:07,800 --> 20:30:08,800
be used for good and bad so they cannot
28581
20:30:09,960 --> 20:30:10,960
also be used by hackers so whenever
28582
20:30:12,360 --> 20:30:13,360
possible if you're connecting over the
28583
20:30:13,744 --> 20:30:14,744
network use a secure shell this is a
28584
20:30:17,720 --> 20:30:18,720
Wireshark we and they call it captures
28585
20:30:20,400 --> 20:30:21,400
as well it's handy to know the uh the
28586
20:30:22,552 --> 20:30:23,552
vernaculars
28587
20:30:24,000 --> 20:30:25,000
um ethernet zero looks like the port
28588
20:30:26,576 --> 20:30:27,576
uh you'll you'll this is the dashboard
28589
20:30:28,976 --> 20:30:29,976
all around here
28590
20:30:30,720 --> 20:30:31,720
and in this part here you can actually
28591
20:30:32,336 --> 20:30:33,336
click on these uh little arrows and it
28592
20:30:35,400 --> 20:30:36,400
will expand so you'll see the layer one
28593
20:30:38,280 --> 20:30:39,280
which probably won't be of interest to
28594
20:30:40,144 --> 20:30:41,144
you then layer two and then you can
28595
20:30:42,896 --> 20:30:43,896
click on this and you will see that it's
28596
20:30:45,120 --> 20:30:46,120
an ARP packet you will see source
28597
20:30:49,616 --> 20:30:50,616
uh destination all and all this kind of
28598
20:30:52,192 --> 20:30:53,192
stuff and then down here is all your
28599
20:30:54,480 --> 20:30:55,480
ones and zeros and hex which you
28600
20:30:57,480 --> 20:30:58,480
probably generally won't be interested
28601
20:30:59,280 --> 20:31:00,280
this looks like it's uh some sort of uh
28602
20:31:02,696 --> 20:31:03,696
pattern over time and you can see
28603
20:31:04,744 --> 20:31:05,744
there's a spike here that's more on here
28604
20:31:08,696 --> 20:31:09,696
and here you can decide exactly what
28605
20:31:10,920 --> 20:31:11,920
traffic you're you're monitoring this is
28606
20:31:13,192 --> 20:31:14,192
SS H telnet and whatever you wanted to
28607
20:31:16,616 --> 20:31:17,616
Monitor and then it's a in a pie chart
28608
20:31:18,960 --> 20:31:19,960
here and obviously a graph form here
28609
20:31:21,720 --> 20:31:22,720
really handy so you can go to your
28610
20:31:24,536 --> 20:31:25,536
customer or your boss uh with all of the
28611
20:31:27,536 --> 20:31:28,536
facts and say when this happens that
28612
20:31:30,600 --> 20:31:31,600
happens when this happens such and such
28613
20:31:33,832 --> 20:31:34,832
Doesn't happen and you can prove what is
28614
20:31:35,824 --> 20:31:36,824
or isn't the issue on the network so um
28615
20:31:39,296 --> 20:31:40,296
please do check out the Wireshark
28616
20:31:42,600 --> 20:31:43,600
certified network analysis
28617
20:31:45,536 --> 20:31:46,536
um
28618
20:31:46,696 --> 20:31:47,696
the network associate sorry
28619
20:31:49,160 --> 20:31:50,160
qualifications really important we've
28620
20:31:51,896 --> 20:31:52,896
got it on um how to net
28621
20:31:56,336 --> 20:31:57,336
work.com
28622
20:31:59,824 --> 20:32:00,824
um I think there's maybe other people
28623
20:32:01,744 --> 20:32:02,744
offered the course but most people just
28624
20:32:03,720 --> 20:32:04,720
seem to just Skip by but this this will
28625
20:32:06,056 --> 20:32:07,056
be a lifesaver if you're looking at
28626
20:32:07,856 --> 20:32:08,856
being a network engineer
28627
20:32:10,256 --> 20:32:11,256
anyway Wi-Fi analyzer this is obviously
28628
20:32:13,744 --> 20:32:14,744
a graphical
28629
20:32:17,760 --> 20:32:18,760
output that has been discovered with the
28630
20:32:20,936 --> 20:32:21,936
piece of software it reports on your
28631
20:32:23,576 --> 20:32:24,576
SSID which you can see here
28632
20:32:26,400 --> 20:32:27,400
and Mac addresses channels use you can
28633
20:32:28,976 --> 20:32:29,976
see the Mac addresses of devices here
28634
20:32:31,504 --> 20:32:32,504
uh challenge use speed that kind of
28635
20:32:34,016 --> 20:32:35,016
thing
28636
20:32:35,216 --> 20:32:36,216
and it represents the output in the
28637
20:32:37,192 --> 20:32:38,192
graphical form as you can see it tells
28638
20:32:39,424 --> 20:32:40,424
you the security protocols and more
28639
20:32:41,400 --> 20:32:42,400
importantly lack of so you could um we
28640
20:32:44,400 --> 20:32:45,400
talked about Rogue access points and
28641
20:32:46,080 --> 20:32:47,080
bring your own device earlier you could
28642
20:32:48,240 --> 20:32:49,240
be doing this in work or you could do it
28643
20:32:50,104 --> 20:32:51,104
as part of a security survey
28644
20:32:52,216 --> 20:32:53,216
and here's another image from the same
28645
20:32:55,856 --> 20:32:56,856
sort of piece of software
28646
20:32:59,464 --> 20:33:00,464
all right bandwidth speed test damage
28647
20:33:01,552 --> 20:33:02,552
we've all used these because if we've
28648
20:33:03,536 --> 20:33:04,536
got problems with our speed at home
28649
20:33:05,872 --> 20:33:06,872
moving at work maybe known as throughput
28650
20:33:08,104 --> 20:33:09,104
testers they can be Hardware software
28651
20:33:10,320 --> 20:33:11,320
based it's easier for us obviously to
28652
20:33:12,536 --> 20:33:13,536
use the piece of software which will
28653
20:33:14,640 --> 20:33:15,640
send a certain amount of packets
28654
20:33:16,680 --> 20:33:17,680
upstream and give you a report of x
28655
20:33:20,280 --> 20:33:21,280
megabits per second then the downstream
28656
20:33:22,800 --> 20:33:23,800
then the same sort of value
28657
20:33:25,144 --> 20:33:26,144
so it injects traffic into the network
28658
20:33:26,824 --> 20:33:27,824
you could actually use this on your Lan
28659
20:33:28,800 --> 20:33:29,800
one or for your home broadband
28660
20:33:31,080 --> 20:33:32,080
connection the handy thing is you'll
28661
20:33:33,056 --> 20:33:34,056
normally get a graph saying um you know
28662
20:33:35,760 --> 20:33:36,760
how fast or slow it is
28663
20:33:38,576 --> 20:33:39,576
free to download if you want super duper
28664
20:33:41,120 --> 20:33:42,120
uh outputs and charts and that kind of
28665
20:33:43,920 --> 20:33:44,920
stuff it'd normally be paid
28666
20:33:45,784 --> 20:33:46,784
CLI this is where the rubber meets a
28667
20:33:48,120 --> 20:33:49,120
road and most Network Engineers kind of
28668
20:33:50,824 --> 20:33:51,824
worry about using these color commands
28669
20:33:53,464 --> 20:33:54,464
like even something simple like ipconfig
28670
20:33:55,800 --> 20:33:56,800
gives you all of this useful information
28671
20:33:57,720 --> 20:33:58,720
here that help you will help you
28672
20:34:00,656 --> 20:34:01,656
troubleshoot now you can use the GUI but
28673
20:34:04,192 --> 20:34:05,192
it's just a little bit more clunky
28674
20:34:05,576 --> 20:34:06,576
you've got to go through a menu to get
28675
20:34:07,256 --> 20:34:08,256
to another menu and then it's only going
28676
20:34:09,424 --> 20:34:10,424
to show you maybe 50 of what you could
28677
20:34:12,536 --> 20:34:13,536
actually see if you use the
28678
20:34:14,760 --> 20:34:15,760
um command line and if you're doing some
28679
20:34:16,616 --> 20:34:17,616
sort of emergency recovery you're
28680
20:34:18,656 --> 20:34:19,656
probably only got command line available
28681
20:34:20,512 --> 20:34:21,512
anyway
28682
20:34:22,744 --> 20:34:23,744
a typical exam question
28683
20:34:25,464 --> 20:34:26,464
ipconfig will give you the TCP
28684
20:34:27,832 --> 20:34:28,832
information on Linux devices this
28685
20:34:29,960 --> 20:34:30,960
ifconfig classic exam question that is
28686
20:34:33,536 --> 20:34:34,536
IP information for your local interfaces
28687
20:34:35,696 --> 20:34:36,696
including your wireless adapter any
28688
20:34:39,960 --> 20:34:40,960
um virtual adapters
28689
20:34:42,720 --> 20:34:43,720
virtual land cards Wireless
28690
20:34:45,800 --> 20:34:46,800
or ethernet
28691
20:34:48,800 --> 20:34:49,800
uh you can use switches to drill down
28692
20:34:51,480 --> 20:34:52,480
for example ipconfig forward slash all
28693
20:34:54,896 --> 20:34:55,896
there's a whole bunch of switches
28694
20:34:56,640 --> 20:34:57,640
actually uh most
28695
20:34:59,824 --> 20:35:00,824
um command line tools will let you issue
28696
20:35:01,744 --> 20:35:02,744
the question mark and then it will save
28697
20:35:03,480 --> 20:35:04,480
these year options
28698
20:35:06,120 --> 20:35:07,120
IP tables this is a Unix command a lot a
28699
20:35:09,656 --> 20:35:10,656
lot of people it's you'll either you you
28700
20:35:11,832 --> 20:35:12,832
use Unix a lot because it's your job or
28701
20:35:15,120 --> 20:35:16,120
you've probably never touched it at all
28702
20:35:16,616 --> 20:35:17,616
but it configures the kernel firewall
28703
20:35:19,192 --> 20:35:20,192
the only reason I mentioned this command
28704
20:35:21,000 --> 20:35:22,000
is because it's in the
28705
20:35:24,176 --> 20:35:25,176
the dreaded syllabus oops syllabus
28706
20:35:27,896 --> 20:35:28,896
so
28707
20:35:28,976 --> 20:35:29,976
um I think just know this command and
28708
20:35:30,896 --> 20:35:31,896
what it does known all this stuff I've
28709
20:35:33,296 --> 20:35:34,296
put it here so you can just see some of
28710
20:35:34,800 --> 20:35:35,800
the options but I really doubt that you
28711
20:35:37,016 --> 20:35:38,016
would need to know it
28712
20:35:38,640 --> 20:35:39,640
um I took this uh lot here from
28713
20:35:42,320 --> 20:35:43,320
tutorialspoint.com if you're nowhere
28714
20:35:44,640 --> 20:35:45,640
look at that URL
28715
20:35:46,144 --> 20:35:47,144
net starts a handy command basically
28716
20:35:48,296 --> 20:35:49,296
short for Network statistics thankfully
28717
20:35:50,216 --> 20:35:51,216
so it's easy to work that out shows your
28718
20:35:52,496 --> 20:35:53,496
active connections tells you the type of
28719
20:35:54,600 --> 20:35:55,600
services you're running and you could be
28720
20:35:56,640 --> 20:35:57,640
in for a surprise
28721
20:35:58,744 --> 20:35:59,744
um if you see things running on your
28722
20:36:00,536 --> 20:36:01,536
device that you you didn't think should
28723
20:36:02,696 --> 20:36:03,696
be there
28724
20:36:04,080 --> 20:36:05,080
there's a few switches let's start minus
28725
20:36:07,504 --> 20:36:08,504
n minus a minus B I'm not sure you'll
28726
20:36:11,576 --> 20:36:12,576
need to know the switches although I
28727
20:36:12,960 --> 20:36:13,960
can't guarantee it active connections
28728
20:36:15,480 --> 20:36:16,480
the applications the connections without
28729
20:36:18,000 --> 20:36:19,000
doing a DNS resolution
28730
20:36:21,000 --> 20:36:22,000
uh here's a net start from uh this is
28731
20:36:25,256 --> 20:36:26,256
from one of my authors actually I
28732
20:36:26,640 --> 20:36:27,640
recognize the name from his device he's
28733
20:36:28,856 --> 20:36:29,856
obviously named his device after himself
28734
20:36:31,080 --> 20:36:32,080
let's start mine is a and you can see
28735
20:36:33,600 --> 20:36:34,600
the state of all of these um ports
28736
20:36:35,936 --> 20:36:36,936
there's an established Port here
28737
20:36:38,464 --> 20:36:39,464
and then you could obviously do a search
28738
20:36:41,576 --> 20:36:42,576
and find out what this is he may what
28739
20:36:43,856 --> 20:36:44,856
may well be connected to a Remote device
28740
20:36:45,896 --> 20:36:46,896
he may be chatting on MSN or Facebook
28741
20:36:49,016 --> 20:36:50,016
Messenger or and you could quite easily
28742
20:36:51,176 --> 20:36:52,176
find out what all these ports are for
28743
20:36:54,376 --> 20:36:55,376
TCP dump and here's the output here
28744
20:36:58,552 --> 20:36:59,552
it's a Unix command it's a sniffing tool
28745
20:37:01,552 --> 20:37:02,552
so what you can do is use it to Snoop
28746
20:37:04,016 --> 20:37:05,016
um the if you're if you want to do the
28747
20:37:06,600 --> 20:37:07,600
snooping it's the Snoop command if
28748
20:37:08,872 --> 20:37:09,872
you're using Solaris
28749
20:37:11,104 --> 20:37:12,104
um pretty specialized a bit of software
28750
20:37:13,552 --> 20:37:14,552
but I've seen some of the network teams
28751
20:37:15,480 --> 20:37:16,480
using Evernote menu you can view the
28752
20:37:17,696 --> 20:37:18,696
packets on the Y app
28753
20:37:19,376 --> 20:37:20,376
pathping
28754
20:37:23,696 --> 20:37:24,696
now this is a tracer command actually
28755
20:37:25,552 --> 20:37:26,552
it's a TCP tool it provides information
28756
20:37:29,160 --> 20:37:30,160
about Network latency and sends icmp
28757
20:37:32,280 --> 20:37:33,280
Echo requests
28758
20:37:35,160 --> 20:37:36,160
and map I think I mentioned this before
28759
20:37:37,080 --> 20:37:38,080
actually she used to discover computers
28760
20:37:39,424 --> 20:37:40,424
and services on a computer network in
28761
20:37:42,000 --> 20:37:43,000
order to create a map
28762
20:37:44,280 --> 20:37:45,280
and you can see
28763
20:37:45,960 --> 20:37:46,960
there's a whole bunch of services here
28764
20:37:47,760 --> 20:37:48,760
many of them probably look familiar to
28765
20:37:49,320 --> 20:37:50,320
you
28766
20:37:51,720 --> 20:37:52,720
and at the end it says Two Hosts up and
28767
20:37:54,000 --> 20:37:55,000
how long it took to scan it
28768
20:37:56,640 --> 20:37:57,640
uh vulnerability scanning Tool uh just
28769
20:37:58,976 --> 20:37:59,976
bear that in mind again typical type of
28770
20:38:01,744 --> 20:38:02,744
question they'll ask you what's nmap
28771
20:38:03,176 --> 20:38:04,176
used for or
28772
20:38:05,104 --> 20:38:06,104
um tick the relevant vulnerability
28773
20:38:06,656 --> 20:38:07,656
scanning tools used for auditing by you
28774
20:38:09,360 --> 20:38:10,360
or obviously whatever can be used for
28775
20:38:11,464 --> 20:38:12,464
good can be used for bad and it can be
28776
20:38:13,376 --> 20:38:14,376
used by hackers
28777
20:38:16,744 --> 20:38:17,744
dig and he said the command has been
28778
20:38:19,016 --> 20:38:20,016
used here
28779
20:38:20,216 --> 20:38:21,216
domain information growth it basically
28780
20:38:23,040 --> 20:38:24,040
sends off a query to DNS servers it's
28781
20:38:26,640 --> 20:38:27,640
the same as the NS lookup tool but this
28782
20:38:29,160 --> 20:38:30,160
particular one is used for Linux devices
28783
20:38:35,576 --> 20:38:36,576
now you can see it's done a search for
28784
20:38:38,160 --> 20:38:39,160
example.com
28785
20:38:39,896 --> 20:38:40,896
and you can see uh the name servers here
28786
20:38:45,656 --> 20:38:46,656
IP address DNS servers cash timers that
28787
20:38:48,656 --> 20:38:49,656
kind of thing
28788
20:38:51,176 --> 20:38:52,176
that looks like a um that looks like
28789
20:38:54,000 --> 20:38:55,000
Google actually
28790
20:38:56,104 --> 20:38:57,104
from if my memory says I think they've
28791
20:38:58,320 --> 20:38:59,320
got eight eight eight and eight eight
28792
20:39:00,480 --> 20:39:01,480
four four you can check for yourself all
28793
20:39:03,960 --> 20:39:04,960
right so looked at some cool stuff uh
28794
20:39:05,824 --> 20:39:06,824
package sniffer Wi-Fi analyzer bandwidth
28795
20:39:08,760 --> 20:39:09,760
speed taster and some important command
28796
20:39:10,616 --> 20:39:11,616
line tools remember we're covering this
28797
20:39:12,784 --> 20:39:13,784
in in other presentations too so this
28798
20:39:14,936 --> 20:39:15,936
was just a subset of all the stuff that
28799
20:39:17,336 --> 20:39:18,336
you need to know
28800
20:39:18,600 --> 20:39:19,600
so that's the end of the presentation
28801
20:39:20,576 --> 20:39:21,576
thanks for watching
28802
20:39:25,030 --> 20:39:26,030
[Music]
28803
20:39:33,440 --> 20:39:34,440
thank you
28804
20:39:41,216 --> 20:39:42,216
welcome to module 15 lesson 2 height
28805
20:39:43,920 --> 20:39:44,920
availability and low balancing we're
28806
20:39:46,376 --> 20:39:47,376
just hitting another syllabus topic here
28807
20:39:49,504 --> 20:39:50,504
um just a brief overview really high
28808
20:39:52,144 --> 20:39:53,144
availability
28809
20:39:52,820 --> 20:39:53,820
[Music]
28810
20:39:54,016 --> 20:39:55,016
vrrp hsrp load balancing and high
28811
20:39:59,936 --> 20:40:00,936
availability this refers to the ability
28812
20:40:02,760 --> 20:40:03,760
of a user to access the service no
28813
20:40:05,400 --> 20:40:06,400
surprise
28814
20:40:06,424 --> 20:40:07,424
High availability is a common networking
28815
20:40:09,832 --> 20:40:10,832
term it refers to the continuous
28816
20:40:12,056 --> 20:40:13,056
availability of a service
28817
20:40:14,336 --> 20:40:15,336
for a higher period than normal now
28818
20:40:17,760 --> 20:40:18,760
obviously we're looking for the 99.99
28819
20:40:20,160 --> 20:40:21,160
percent
28820
20:40:21,656 --> 20:40:22,656
in order to get the highest possible
28821
20:40:24,000 --> 20:40:25,000
availability we usually need more than
28822
20:40:26,512 --> 20:40:27,512
one other thing
28823
20:40:29,160 --> 20:40:30,160
for example um some Cisco switches come
28824
20:40:31,976 --> 20:40:32,976
with
28825
20:40:32,896 --> 20:40:33,896
to power supplies
28826
20:40:35,872 --> 20:40:36,872
and even
28827
20:40:37,920 --> 20:40:38,920
even this has been improved upon so they
28828
20:40:40,856 --> 20:40:41,856
have not just the fact they've got two
28829
20:40:42,896 --> 20:40:43,896
power supplies but they're hot swappable
28830
20:40:44,896 --> 20:40:45,896
so what that means is you don't need to
28831
20:40:47,400 --> 20:40:48,400
reboot the switch you can pull one out
28832
20:40:49,744 --> 20:40:50,744
the inactive one and then slot another
28833
20:40:52,496 --> 20:40:53,496
one in and then you've got two active
28834
20:40:54,600 --> 20:40:55,600
power supply units and in case one fails
28835
20:40:59,760 --> 20:41:00,760
so measured as a percentage of uptime
28836
20:41:01,744 --> 20:41:02,744
which is five minutes a year
28837
20:41:04,872 --> 20:41:05,872
uh for a network to be highly
28838
20:41:06,896 --> 20:41:07,896
availability it should survive any kind
28839
20:41:09,720 --> 20:41:10,720
of failure
28840
20:41:10,856 --> 20:41:11,856
I'm not saying there's such a thing
28841
20:41:13,616 --> 20:41:14,616
doesn't exist but even the most robust
28842
20:41:16,080 --> 20:41:17,080
networks there was a recent outage due
28843
20:41:18,240 --> 20:41:19,240
to
28844
20:41:19,080 --> 20:41:20,080
um severe flooding in Australia I think
28845
20:41:22,192 --> 20:41:23,192
it was just a few months ago where it
28846
20:41:23,640 --> 20:41:24,640
took out Amazon uh S3
28847
20:41:27,600 --> 20:41:28,600
service so which you would think would
28848
20:41:30,176 --> 20:41:31,176
be one of the most available and secure
28849
20:41:31,976 --> 20:41:32,976
and robust uh hosting Platforms in the
28850
20:41:35,104 --> 20:41:36,104
world but even some of those customers
28851
20:41:36,536 --> 20:41:37,536
were taken out
28852
20:41:38,104 --> 20:41:39,104
so high availability can be achieved by
28853
20:41:40,744 --> 20:41:41,744
configuring redundant components so if
28854
20:41:42,360 --> 20:41:43,360
one one part of it fails the other part
28855
20:41:44,576 --> 20:41:45,576
takes over
28856
20:41:47,760 --> 20:41:48,760
now in the context of a routing we've
28857
20:41:51,240 --> 20:41:52,240
got protocols such as vrrp Virtual
28858
20:41:54,176 --> 20:41:55,176
Router redundancy protocol and hsrp
28859
20:41:57,176 --> 20:41:58,176
which is done by router protocol
28860
20:41:59,872 --> 20:42:00,872
these are what are what is known as um
28861
20:42:03,056 --> 20:42:04,056
High availability protocols
28862
20:42:07,016 --> 20:42:08,016
these enable multiple multiple routers
28863
20:42:10,256 --> 20:42:11,256
oral layer 3 switches in fact to act as
28864
20:42:13,376 --> 20:42:14,376
Virtual Router with a virtual IP address
28865
20:42:17,872 --> 20:42:18,872
a default gateway is configured with
28866
20:42:19,920 --> 20:42:20,920
this virtual IP address so one router
28867
20:42:22,496 --> 20:42:23,496
will be active and this handles all the
28868
20:42:24,240 --> 20:42:25,240
requests to the default gateway and the
28869
20:42:26,464 --> 20:42:27,464
other router will be a standby so the
28870
20:42:28,376 --> 20:42:29,376
other router actually takes over if the
28871
20:42:30,360 --> 20:42:31,360
main router goes down now this isn't
28872
20:42:32,400 --> 20:42:33,400
load balancing because um you've got one
28873
20:42:34,680 --> 20:42:35,680
master router and the other one is a
28874
20:42:37,080 --> 20:42:38,080
slave or backup depending on the
28875
20:42:39,296 --> 20:42:40,296
protocol you use they have different
28876
20:42:41,336 --> 20:42:42,336
terms so here's an image of uh the Cisco
28877
20:42:45,240 --> 20:42:46,240
hot standby router protocol
28878
20:42:47,576 --> 20:42:48,576
at the top you with the red and the blue
28879
20:42:50,336 --> 20:42:51,336
you got a layer 3 switch
28880
20:42:53,160 --> 20:42:54,160
it should be another there we go
28881
20:42:56,512 --> 20:42:57,512
so uh we'll see you see the host on the
28882
20:43:00,056 --> 20:43:01,056
bottom they both have the same default
28883
20:43:02,824 --> 20:43:03,824
Gateway the Gateway is 10.10.10.1 now
28884
20:43:07,824 --> 20:43:08,824
10.10.10.1 is configured as a virtual IP
28885
20:43:11,216 --> 20:43:12,216
address on the two layer three devices
28886
20:43:14,104 --> 20:43:15,104
on the top
28887
20:43:15,536 --> 20:43:16,536
these two devices are connected and they
28888
20:43:18,424 --> 20:43:19,424
monitor each other so if one goes down
28889
20:43:20,640 --> 20:43:21,640
the other one takes over you see the
28890
20:43:23,512 --> 20:43:24,512
priority on the right hand switch is 100
28891
20:43:26,336 --> 20:43:27,336
the priority on the left hand switch is
28892
20:43:29,336 --> 20:43:30,336
105 so it's got a higher priority so
28893
20:43:32,512 --> 20:43:33,512
this one in the case of hsrp will be the
28894
20:43:35,104 --> 20:43:36,104
primary router
28895
20:43:37,744 --> 20:43:38,744
uh all traffic will go via this router
28896
20:43:40,920 --> 20:43:41,920
until there's an issue with it if it
28897
20:43:43,376 --> 20:43:44,376
goes down then all traffic immediately
28898
20:43:45,056 --> 20:43:46,056
in a split second swaps to the standby
28899
20:43:48,480 --> 20:43:49,480
router which is on the rides they both
28900
20:43:51,000 --> 20:43:52,000
run a virtual Mac address we don't need
28901
20:43:53,216 --> 20:43:54,216
to worry about that because I don't
28902
20:43:54,176 --> 20:43:55,176
think it'd be asked but they run a
28903
20:43:55,440 --> 20:43:56,440
virtual Mac address so that um a layer 2
28904
20:43:58,800 --> 20:43:59,800
connectivity works also
28905
20:44:01,400 --> 20:44:02,400
I think that's all we need to know about
28906
20:44:03,656 --> 20:44:04,656
this diagram
28907
20:44:06,656 --> 20:44:07,656
load balancing is a distribution of work
28908
20:44:10,256 --> 20:44:11,256
across two or more resources such as
28909
20:44:13,080 --> 20:44:14,080
servers and networks if you have a
28910
20:44:15,720 --> 20:44:16,720
server overloaded with requests then we
28911
20:44:17,512 --> 20:44:18,512
can have several servers share the
28912
20:44:19,256 --> 20:44:20,256
burden of that single server in fact
28913
20:44:21,424 --> 20:44:22,424
even better than that you can
28914
20:44:23,872 --> 20:44:24,872
um it will it can work so that the load
28915
20:44:26,936 --> 20:44:27,936
is balanced automatically so you don't
28916
20:44:28,800 --> 20:44:29,800
have to wait till one server to be
28917
20:44:30,296 --> 20:44:31,296
overloaded the load is shared over two
28918
20:44:33,176 --> 20:44:34,176
or more servers
28919
20:44:36,240 --> 20:44:37,240
now the other thing is just going back
28920
20:44:38,040 --> 20:44:39,040
to that last point the servers are
28921
20:44:39,896 --> 20:44:40,896
acting as a single server so devices
28922
20:44:41,760 --> 20:44:42,760
don't realize that load balancing is
28923
20:44:43,680 --> 20:44:44,680
taking place the servers are acting as a
28924
20:44:46,496 --> 20:44:47,496
group of servers with the actual hosts
28925
20:44:48,832 --> 20:44:49,832
that are contacting their services on
28926
20:44:50,400 --> 20:44:51,400
these servers for example
28927
20:44:52,680 --> 20:44:53,680
um surfing a web site and doesn't don't
28928
20:44:55,552 --> 20:44:56,552
realize then load balancing is taking
28929
20:44:57,424 --> 20:44:58,424
place
28930
20:44:58,496 --> 20:44:59,496
so here's an image of load balancing
28931
20:45:00,360 --> 20:45:01,360
you've got two load balances here so one
28932
20:45:03,424 --> 20:45:04,424
would be
28933
20:45:04,552 --> 20:45:05,552
um redundant or possibly taking a part
28934
20:45:07,680 --> 20:45:08,680
of the load from the other one
28935
20:45:09,536 --> 20:45:10,536
and then we've got an array of servers
28936
20:45:12,656 --> 20:45:13,656
providing whichever Services they they
28937
20:45:14,696 --> 20:45:15,696
may be FTP or web services
28938
20:45:18,424 --> 20:45:19,424
so load is distributed uh across the
28939
20:45:22,376 --> 20:45:23,376
servers they'll all have the same IP
28940
20:45:24,536 --> 20:45:25,536
address
28941
20:45:25,616 --> 20:45:26,616
and if there's a problem with one of the
28942
20:45:27,896 --> 20:45:28,896
servers that will be removed from
28943
20:45:29,576 --> 20:45:30,576
rotation if they're not responding I
28944
20:45:32,400 --> 20:45:33,400
presume you'll have some sort of
28945
20:45:33,480 --> 20:45:34,480
reporting software that will send a
28946
20:45:35,040 --> 20:45:36,040
message to the administrator saying one
28947
20:45:37,320 --> 20:45:38,320
of the servers has been taken out of
28948
20:45:38,824 --> 20:45:39,824
rotation so that can be looked into
28949
20:45:41,400 --> 20:45:42,400
some of the benefits optimization of
28950
20:45:44,104 --> 20:45:45,104
resources you get faster throughput
28951
20:45:46,616 --> 20:45:47,616
obviously requires careful planning for
28952
20:45:48,720 --> 20:45:49,720
all your bandwidth efficiency
28953
20:45:52,016 --> 20:45:53,016
High availability which is the whole
28954
20:45:53,872 --> 20:45:54,872
point of the presentation so we've
28955
20:45:55,976 --> 20:45:56,976
looked at high availability two types of
28956
20:45:58,440 --> 20:45:59,440
protocols vrrp and hsrp
28957
20:46:02,216 --> 20:46:03,216
low balancing all right that's all for
28958
20:46:04,744 --> 20:46:05,744
now thanks for watching
28959
20:46:11,200 --> 20:46:12,200
[Music]
28960
20:46:20,536 --> 20:46:21,536
thank you
28961
20:46:27,424 --> 20:46:28,424
welcome to module 15 lesson 3 we're
28962
20:46:30,000 --> 20:46:31,000
looking at SNMP syslog and s-i-e-m
28963
20:46:34,976 --> 20:46:35,976
these are exam objectives
28964
20:46:38,824 --> 20:46:39,824
you could go into each of these subjects
28965
20:46:40,552 --> 20:46:41,552
in quite a lot of detail actually
28966
20:46:41,936 --> 20:46:42,936
there's the entire book so that's an MP
28967
20:46:45,424 --> 20:46:46,424
which um we won't we'll only be doing an
28968
20:46:48,896 --> 20:46:49,896
overview so you're familiar with the
28969
20:46:51,000 --> 20:46:52,000
the terms used we'll talk about these
28970
20:46:54,656 --> 20:46:55,656
services
28971
20:46:56,464 --> 20:46:57,464
Harrison MP Works email Cinemas SMS
28972
20:47:00,000 --> 20:47:01,000
alerting
28973
20:47:01,104 --> 20:47:02,104
syslogs and the benefits and Siem SNMP
28974
20:47:04,856 --> 20:47:05,856
you'll be referring to a fair amount as
28975
20:47:08,160 --> 20:47:09,160
a network engineer a guess I get it just
28976
20:47:10,680 --> 20:47:11,680
depends on your network some of the
28977
20:47:12,720 --> 20:47:13,720
larger networks I've worked uh on you
28978
20:47:17,512 --> 20:47:18,512
actually have a team that deals with any
28979
20:47:19,800 --> 20:47:20,800
SNMP reporting and any configurations or
28980
20:47:23,464 --> 20:47:24,464
perhaps as a network engineer you'd have
28981
20:47:26,160 --> 20:47:27,160
to enable SNMP reporting on a particular
28982
20:47:29,576 --> 20:47:30,576
device
28983
20:47:30,784 --> 20:47:31,784
do some testing to make sure that the
28984
20:47:33,240 --> 20:47:34,240
receiving station the network management
28985
20:47:35,512 --> 20:47:36,512
station can receive information which we
28986
20:47:39,240 --> 20:47:40,240
refer to as traps from the device and
28987
20:47:42,000 --> 20:47:43,000
then you will sign off that device as
28988
20:47:44,104 --> 20:47:45,104
compatible
28989
20:47:46,616 --> 20:47:47,616
so SNMP is an application layer protocol
28990
20:47:49,376 --> 20:47:50,376
and the idea is it Exchange Management
28991
20:47:51,784 --> 20:47:52,784
data between the devices on the network
28992
20:47:54,176 --> 20:47:55,176
or from a certain device to the network
28993
20:47:57,296 --> 20:47:58,296
management station
28994
20:47:59,872 --> 20:48:00,872
issues to Monitor and manage devices on
28995
20:48:02,160 --> 20:48:03,160
the network such as router switches
28996
20:48:03,960 --> 20:48:04,960
servers and it even drills down to
28997
20:48:06,296 --> 20:48:07,296
individual ports for example if you have
28998
20:48:08,464 --> 20:48:09,464
a switch
28999
20:48:09,784 --> 20:48:10,784
with 24 ports the SNMP manager depending
29000
20:48:13,504 --> 20:48:14,504
on the software you have some of it's
29001
20:48:14,936 --> 20:48:15,936
free and some of it's quite expensive
29002
20:48:18,240 --> 20:48:19,240
and it can drill down and show you a
29003
20:48:21,120 --> 20:48:22,120
pictorial view of each port on the
29004
20:48:23,936 --> 20:48:24,936
switch including the power and power
29005
20:48:27,296 --> 20:48:28,296
button and you can enable or disable and
29006
20:48:31,552 --> 20:48:32,552
monitor and manage individual ports so
29007
20:48:33,536 --> 20:48:34,536
it's very handy and very powerful
29008
20:48:36,000 --> 20:48:37,000
SNMP implementation consists of a
29009
20:48:38,824 --> 20:48:39,824
managed device
29010
20:48:40,440 --> 20:48:41,440
the SNMP agent
29011
20:48:42,960 --> 20:48:43,960
little piece of software the SNMP
29012
20:48:45,600 --> 20:48:46,600
manager which is normally a PC or server
29013
20:48:49,504 --> 20:48:50,504
that monitors the network and then
29014
20:48:51,656 --> 20:48:52,656
reporting is done on there pictorially
29015
20:48:54,240 --> 20:48:55,240
usually
29016
20:48:55,744 --> 20:48:56,744
the graphical user interface
29017
20:48:58,192 --> 20:48:59,192
the manage device on the network it
29018
20:49:00,120 --> 20:49:01,120
requires some kind of monitoring and it
29019
20:49:02,104 --> 20:49:03,104
can be
29020
20:49:03,000 --> 20:49:04,000
it would be your servers switches
29021
20:49:05,160 --> 20:49:06,160
routers firewalls that kind of thing
29022
20:49:08,280 --> 20:49:09,280
an example is a storage array
29023
20:49:11,600 --> 20:49:12,600
SNMP agent is a program that runs on the
29024
20:49:14,936 --> 20:49:15,936
manage device so these need to be
29025
20:49:16,376 --> 20:49:17,376
written
29026
20:49:17,336 --> 20:49:18,336
by whoever the vendor is usually so it
29027
20:49:21,240 --> 20:49:22,240
can comply with the RFC
29028
20:49:25,192 --> 20:49:26,192
the SNMP collects information from the
29029
20:49:27,176 --> 20:49:28,176
device and sends it to the SNMP manager
29030
20:49:31,080 --> 20:49:32,080
the SNMP manager is typically a computer
29031
20:49:33,896 --> 20:49:34,896
that has the software running for us in
29032
20:49:37,144 --> 20:49:38,144
mp and a lot of the time it's graphical
29033
20:49:40,192 --> 20:49:41,192
user interface you'll see different
29034
20:49:42,296 --> 20:49:43,296
images and diagrams and Reporting pie
29035
20:49:44,872 --> 20:49:45,872
charts and that kind of thing
29036
20:49:47,280 --> 20:49:48,280
this communicates with the SNMP agent
29037
20:49:50,936 --> 20:49:51,936
management information base we call
29038
20:49:52,856 --> 20:49:53,856
these mibs we don't normally say MIB
29039
20:49:54,976 --> 20:49:55,976
when we speak to Engineers the maybe is
29040
20:49:58,376 --> 20:49:59,376
a database maintained by the SNMP agent
29041
20:50:03,424 --> 20:50:04,424
it contains information about the
29042
20:50:04,920 --> 20:50:05,920
managed device which is shared by both
29043
20:50:06,600 --> 20:50:07,600
the SNMP agent and the manager
29044
20:50:10,440 --> 20:50:11,440
so SNMP is typically enabled when you
29045
20:50:13,256 --> 20:50:14,256
have a storage system
29046
20:50:14,936 --> 20:50:15,936
again it depends on your setup
29047
20:50:18,600 --> 20:50:19,600
whenever whenever a specific event
29048
20:50:20,640 --> 20:50:21,640
occurs in the storage system this is an
29049
20:50:22,552 --> 20:50:23,552
MP agent running on it will notify the
29050
20:50:24,896 --> 20:50:25,896
manager and it sends a message now what
29051
20:50:26,936 --> 20:50:27,936
happens after that depends on how you've
29052
20:50:28,680 --> 20:50:29,680
configured it it could trigger a number
29053
20:50:30,176 --> 20:50:31,176
of events
29054
20:50:32,336 --> 20:50:33,336
or just be stored so you can see the
29055
20:50:36,832 --> 20:50:37,832
act I will act now by the SNMP manager
29056
20:50:39,600 --> 20:50:40,600
what actually happens
29057
20:50:42,360 --> 20:50:43,360
the Trap is in the is an event that's
29058
20:50:44,824 --> 20:50:45,824
reported the SNMP manager will receive
29059
20:50:47,512 --> 20:50:48,512
the event and take action type of
29060
20:50:50,040 --> 20:50:51,040
actions could be
29061
20:50:51,600 --> 20:50:52,600
um an email you can configure it to send
29062
20:50:54,240 --> 20:50:55,240
an SMS to the network engineer or a
29063
20:50:57,656 --> 20:50:58,656
number of people
29064
20:50:59,696 --> 20:51:00,696
you can even have um
29065
20:51:02,104 --> 20:51:03,104
an automatic um
29066
20:51:04,320 --> 20:51:05,320
phone number dialed or number of numbers
29067
20:51:06,424 --> 20:51:07,424
dialed voice message is sent it just
29068
20:51:09,296 --> 20:51:10,296
depends on how you how you configure it
29069
20:51:11,696 --> 20:51:12,696
and how important this particular
29070
20:51:13,080 --> 20:51:14,080
message is
29071
20:51:14,512 --> 20:51:15,512
quote from Wikipedia
29072
20:51:16,464 --> 20:51:17,464
SNMP agent receives requests on UDP Port
29073
20:51:19,856 --> 20:51:20,856
161
29074
20:51:21,600 --> 20:51:22,600
it can send requests from any available
29075
20:51:23,824 --> 20:51:24,824
Source port to port 161. the age of
29076
20:51:27,536 --> 20:51:28,536
response is generally set back send back
29077
20:51:30,056 --> 20:51:31,056
to the source port on the manager the
29078
20:51:32,280 --> 20:51:33,280
manager receives notifications these are
29079
20:51:34,552 --> 20:51:35,552
known as traps and inform requests
29080
20:51:36,480 --> 20:51:37,480
there's other types of messages these
29081
20:51:39,000 --> 20:51:40,000
are on Port 162. so basically UDP ports
29082
20:51:42,656 --> 20:51:43,656
161 and 162 is used by SNMP
29083
20:51:47,696 --> 20:51:48,696
moving on to a syslog which has got
29084
20:51:50,872 --> 20:51:51,872
quite a lot of prominence in the Cisco
29085
20:51:53,720 --> 20:51:54,720
CCNA exams
29086
20:51:56,216 --> 20:51:57,216
it's a protocol for exchanging log
29087
20:51:58,496 --> 20:51:59,496
messages so syslog generally sits on a
29088
20:52:01,800 --> 20:52:02,800
syslog server although you can configure
29089
20:52:04,496 --> 20:52:05,496
it a router to be a syslog server the
29090
20:52:08,464 --> 20:52:09,464
general rule is leave these devices like
29091
20:52:11,104 --> 20:52:12,104
a router to do the main job it's
29092
20:52:12,720 --> 20:52:13,720
designed for
29093
20:52:13,976 --> 20:52:14,976
instead of um using it to allocate DHCP
29094
20:52:17,696 --> 20:52:18,696
addresses and record syslog messages
29095
20:52:20,104 --> 20:52:21,104
although it can do these and a lot more
29096
20:52:22,744 --> 20:52:23,744
things
29097
20:52:23,760 --> 20:52:24,760
it can be used by devices on the network
29098
20:52:26,104 --> 20:52:27,104
to move all the audit logs to a central
29099
20:52:29,464 --> 20:52:30,464
login server again this is called the
29100
20:52:31,800 --> 20:52:32,800
syslog server
29101
20:52:34,616 --> 20:52:35,616
why would you do it it allows the
29102
20:52:36,784 --> 20:52:37,784
consolidation of audit logs from
29103
20:52:39,000 --> 20:52:40,000
multiple devices to a single place
29104
20:52:40,800 --> 20:52:41,800
basically it's for to give you usable
29105
20:52:44,240 --> 20:52:45,240
information and data you can have
29106
20:52:47,872 --> 20:52:48,872
different levels of syslog messaging
29107
20:52:50,336 --> 20:52:51,336
from urgent messages to just general
29108
20:52:52,920 --> 20:52:53,920
reporting and how and what it actually
29109
20:52:56,760 --> 20:52:57,760
does is down to you to configure
29110
20:52:58,936 --> 20:52:59,936
depending on your particular needs on
29111
20:53:01,192 --> 20:53:02,192
the network
29112
20:53:03,536 --> 20:53:04,536
okay lastly s-i-e-m security information
29113
20:53:06,600 --> 20:53:07,600
and event manager
29114
20:53:08,696 --> 20:53:09,696
it's a set of software products and
29115
20:53:11,216 --> 20:53:12,216
services that are used to monitor a
29116
20:53:12,960 --> 20:53:13,960
network
29117
20:53:14,040 --> 20:53:15,040
what it gives you is a real-time output
29118
20:53:16,192 --> 20:53:17,192
of security alerts generated by Network
29119
20:53:18,536 --> 20:53:19,536
and network Hardware so it's definitely
29120
20:53:21,000 --> 20:53:22,000
got a security bias
29121
20:53:23,640 --> 20:53:24,640
It's a combination of sem security event
29122
20:53:26,216 --> 20:53:27,216
manager and Sim security information
29123
20:53:29,040 --> 20:53:30,040
management
29124
20:53:32,824 --> 20:53:33,824
the security event management deals with
29125
20:53:34,920 --> 20:53:35,920
the real-time monitoring and
29126
20:53:36,176 --> 20:53:37,176
notification of security events
29127
20:53:38,576 --> 20:53:39,576
the Sim deals with the collection of the
29128
20:53:40,680 --> 20:53:41,680
log files into a central Repository
29129
20:53:44,512 --> 20:53:45,512
a lot of the time as with other
29130
20:53:46,192 --> 20:53:47,192
protocols like this you would have a
29131
20:53:48,120 --> 20:53:49,120
graphical analysis giving you some sort
29132
20:53:50,872 --> 20:53:51,872
of meaningful data that you can
29133
20:53:52,744 --> 20:53:53,744
interpret
29134
20:53:54,480 --> 20:53:55,480
the Siem Solutions are used to log
29135
20:53:57,000 --> 20:53:58,000
security data and generate reports a lot
29136
20:54:00,480 --> 20:54:01,480
of the time for compliance and security
29137
20:54:01,976 --> 20:54:02,976
compliance is a whole
29138
20:54:04,680 --> 20:54:05,680
new and expanded area
29139
20:54:07,440 --> 20:54:08,440
a lot of the time for you to comply with
29140
20:54:10,680 --> 20:54:11,680
and National standards and requirements
29141
20:54:13,800 --> 20:54:14,800
for security
29142
20:54:16,080 --> 20:54:17,080
one example is checkpoint event here
29143
20:54:18,360 --> 20:54:19,360
which you can Google and look at some
29144
20:54:20,464 --> 20:54:21,464
more information if you want to do some
29145
20:54:22,104 --> 20:54:23,104
research but that's um for now summary
29146
20:54:25,256 --> 20:54:26,256
is SNMP components manage devices and
29147
20:54:28,744 --> 20:54:29,744
agents and managers
29148
20:54:30,720 --> 20:54:31,720
mibs we've talked about how SNMP works
29149
20:54:34,872 --> 20:54:35,872
alerting syslog
29150
20:54:38,216 --> 20:54:39,216
and why we use this log and Siem okay
29151
20:54:41,464 --> 20:54:42,464
that's all for now thanks for watching
29152
20:54:47,600 --> 20:54:48,600
[Music]
29153
20:54:56,296 --> 20:54:57,296
thank you
29154
20:55:03,720 --> 20:55:04,720
welcome to module 16 lesson one web
29155
20:55:06,536 --> 20:55:07,536
services
29156
20:55:07,976 --> 20:55:08,976
this would obviously uh be a massive
29157
20:55:10,376 --> 20:55:11,376
area we're just touching on the things
29158
20:55:12,424 --> 20:55:13,424
that are covered in the syllabus what
29159
20:55:15,656 --> 20:55:16,656
are web services XML
29160
20:55:19,160 --> 20:55:20,160
programming languages and web services
29161
20:55:21,496 --> 20:55:22,496
their components used by web services
29162
20:55:24,440 --> 20:55:25,440
how are web service works
29163
20:55:27,832 --> 20:55:28,832
I think uh this has probably been put in
29164
20:55:30,360 --> 20:55:31,360
in as much as you probably you may be
29165
20:55:32,936 --> 20:55:33,936
asked to do some sort of troubleshooting
29166
20:55:34,744 --> 20:55:35,744
not uh in the respective web programming
29167
20:55:38,576 --> 20:55:39,576
but perhaps accessor through the network
29168
20:55:43,016 --> 20:55:44,016
or firewalls or some sort of
29169
20:55:44,936 --> 20:55:45,936
troubleshooting so you may need to
29170
20:55:47,104 --> 20:55:48,104
communicate with the web programmers at
29171
20:55:49,440 --> 20:55:50,440
some point
29172
20:55:51,000 --> 20:55:52,000
what are they there's a whole bunch of
29173
20:55:52,920 --> 20:55:53,920
applications that use Open Standards
29174
20:55:55,320 --> 20:55:56,320
such as Excel
29175
20:55:58,320 --> 20:55:59,320
soap wsdl
29176
20:56:02,160 --> 20:56:03,160
uddi
29177
20:56:04,552 --> 20:56:05,552
uses they used to exchange data between
29178
20:56:06,832 --> 20:56:07,832
the web-based applications over an IP
29179
20:56:09,960 --> 20:56:10,960
network and this is just a massively
29180
20:56:12,976 --> 20:56:13,976
expanded area and always has been since
29181
20:56:16,160 --> 20:56:17,160
HTTP was first used to display web pages
29182
20:56:20,872 --> 20:56:21,872
it's been improved upon over and over
29183
20:56:23,512 --> 20:56:24,512
again to deal with them issues speed
29184
20:56:26,824 --> 20:56:27,824
security
29185
20:56:27,920 --> 20:56:28,920
usability mobile devices it's just never
29186
20:56:31,616 --> 20:56:32,616
ending
29187
20:56:34,920 --> 20:56:35,920
so in a web service we already know the
29188
20:56:37,920 --> 20:56:38,920
HTTP is used to transfer
29189
20:56:41,512 --> 20:56:42,512
um machine readable formats such as the
29190
20:56:43,680 --> 20:56:44,680
following XML Json
29191
20:56:48,296 --> 20:56:49,296
and Jason when different software
29192
20:56:51,424 --> 20:56:52,424
Services onto stage dates with each
29193
20:56:53,104 --> 20:56:54,104
other a web service allows them to do
29194
20:56:54,896 --> 20:56:55,896
this over the internet
29195
20:56:58,440 --> 20:56:59,440
software application that requests the
29196
20:57:00,424 --> 20:57:01,424
data is called a service and you can
29197
20:57:02,760 --> 20:57:03,760
tweak these way in most of your browsers
29198
20:57:05,824 --> 20:57:06,824
such as their Google Chrome or Firefox
29199
20:57:08,760 --> 20:57:09,760
they normally have ways you can manage
29200
20:57:11,104 --> 20:57:12,104
extensions or um the back end
29201
20:57:15,056 --> 20:57:16,056
to a grade to a lesser extent
29202
20:57:18,176 --> 20:57:19,176
software application that serves the
29203
20:57:20,160 --> 20:57:21,160
data is called a service provider
29204
20:57:23,104 --> 20:57:24,104
and web services are a means of um
29205
20:57:25,824 --> 20:57:26,824
interoperating between different
29206
20:57:27,536 --> 20:57:28,536
software systems
29207
20:57:31,616 --> 20:57:32,616
the software applications develop using
29208
20:57:34,256 --> 20:57:35,256
a whole variety of programmer languages
29209
20:57:37,144 --> 20:57:38,144
and normally you'll have somebody
29210
20:57:38,784 --> 20:57:39,784
specializes in one or more and you can
29211
20:57:41,640 --> 20:57:42,640
see a few in the Fig there some have
29212
20:57:44,280 --> 20:57:45,280
been depreciated such as Flash and due
29213
20:57:47,760 --> 20:57:48,760
to security issues
29214
20:57:51,832 --> 20:57:52,832
season for applications want to exchange
29215
20:57:54,176 --> 20:57:55,176
data they should be able to communicate
29216
20:57:56,040 --> 20:57:57,040
with each other this may possibly be
29217
20:57:59,280 --> 20:58:00,280
where you have become involved as the
29218
20:58:01,552 --> 20:58:02,552
network engineer
29219
20:58:03,656 --> 20:58:04,656
data exchange shouldn't depend on any
29220
20:58:05,760 --> 20:58:06,760
particular programming language
29221
20:58:08,104 --> 20:58:09,104
so there's a need for a common language
29222
20:58:09,360 --> 20:58:10,360
that allow different software
29223
20:58:10,744 --> 20:58:11,744
applications to send and receive data
29224
20:58:12,720 --> 20:58:13,720
over the web
29225
20:58:14,512 --> 20:58:15,512
most types of software can interpret
29226
20:58:17,280 --> 20:58:18,280
what's known as XML tags
29227
20:58:20,104 --> 20:58:21,104
this stands for extensible Market
29228
20:58:22,016 --> 20:58:23,016
bandwidge which you can learn if you so
29229
20:58:24,240 --> 20:58:25,240
choose
29230
20:58:25,744 --> 20:58:26,744
it's a standard language for web-based
29231
20:58:27,536 --> 20:58:28,536
applications to communicate with one
29232
20:58:29,640 --> 20:58:30,640
another
29233
20:58:30,656 --> 20:58:31,656
the exchange of data happens through XML
29234
20:58:33,656 --> 20:58:34,656
files
29235
20:58:36,240 --> 20:58:37,240
XML is a markup language it defines a
29236
20:58:39,000 --> 20:58:40,000
set of rules for encoding documents in a
29237
20:58:40,920 --> 20:58:41,920
format that we can read as humans
29238
20:58:43,376 --> 20:58:44,376
generally you need to be a programmer to
29239
20:58:45,480 --> 20:58:46,480
understand what they mean but it could
29240
20:58:47,400 --> 20:58:48,400
also be read by the machines
29241
20:58:51,440 --> 20:58:52,440
so here's an example of an XML file you
29242
20:58:54,896 --> 20:58:55,896
can see it's marked as XML at the top
29243
20:58:57,000 --> 20:58:58,000
the version and then there's various
29244
20:59:00,536 --> 20:59:01,536
um prompts within the greater than and
29245
20:59:03,656 --> 20:59:04,656
less than markers and also the actual
29246
20:59:07,504 --> 20:59:08,504
text in between Network 100 status pass
29247
20:59:11,424 --> 20:59:12,424
subject Hardware Mach 100
29248
20:59:17,400 --> 20:59:18,400
so you've seen an example easy to read
29249
20:59:19,552 --> 20:59:20,552
it once obviously once you've learned
29250
20:59:21,896 --> 20:59:22,896
what it all means and how it works but
29251
20:59:23,640 --> 20:59:24,640
it's also easy for the machine to read
29252
20:59:26,400 --> 20:59:27,400
also
29253
20:59:28,192 --> 20:59:29,192
allows you to see what's been sent
29254
20:59:29,824 --> 20:59:30,824
between the web-based applications
29255
20:59:33,832 --> 20:59:34,832
web services web applications can send
29256
20:59:36,424 --> 20:59:37,424
data using the XML format they can also
29257
20:59:38,872 --> 20:59:39,872
retrieve data from an XML file
29258
20:59:42,424 --> 20:59:43,424
a standard web service uses the
29259
20:59:44,512 --> 20:59:45,512
following components soap
29260
20:59:47,280 --> 20:59:48,280
this stands for a simple object access
29261
20:59:50,160 --> 20:59:51,160
protocol
29262
20:59:51,720 --> 20:59:52,720
this is actually used to transfer the
29263
20:59:53,696 --> 20:59:54,696
data
29264
20:59:56,760 --> 20:59:57,760
uddi stands for Universal description
29265
20:59:59,336 --> 21:00:00,336
Discovery and integration
29266
21:00:01,800 --> 21:00:02,800
directory that defines which Software
29267
21:00:03,896 --> 21:00:04,896
System should be contacted for which
29268
21:00:06,000 --> 21:00:07,000
type of data
29269
21:00:09,440 --> 21:00:10,440
wsdl stands for web services description
29270
21:00:12,896 --> 21:00:13,896
language
29271
21:00:14,160 --> 21:00:15,160
used for describing the services
29272
21:00:15,784 --> 21:00:16,784
available
29273
21:00:18,720 --> 21:00:19,720
how are web service works it uses XML to
29274
21:00:22,144 --> 21:00:23,144
tag the data soap to transfer the data
29275
21:00:24,720 --> 21:00:25,720
and then wsdl to describe the
29276
21:00:27,360 --> 21:00:28,360
availability of a service it's worth
29277
21:00:29,720 --> 21:00:30,720
writing this out if you haven't already
29278
21:00:31,744 --> 21:00:32,744
if you're not making notes so you
29279
21:00:33,720 --> 21:00:34,720
understand which
29280
21:00:35,464 --> 21:00:36,464
um part performs which service because
29281
21:00:38,400 --> 21:00:39,400
this is the most likely thing you're
29282
21:00:39,720 --> 21:00:40,720
going to be asked a question about
29283
21:00:43,616 --> 21:00:44,616
so we've looked briefly at web services
29284
21:00:45,552 --> 21:00:46,552
XML programming languages and web
29285
21:00:48,000 --> 21:00:49,000
services
29286
21:00:48,976 --> 21:00:49,976
components how web service works that's
29287
21:00:52,552 --> 21:00:53,552
all for now thanks for listening
29288
21:00:58,700 --> 21:00:59,700
[Music]
29289
21:01:14,576 --> 21:01:15,576
welcome to module 16 lesson 2 unified
29290
21:01:17,464 --> 21:01:18,464
communication
29291
21:01:19,552 --> 21:01:20,552
just call this UC usually to save a lot
29292
21:01:23,216 --> 21:01:24,216
of breath as with everything
29293
21:01:25,856 --> 21:01:26,856
uh different media the same
29294
21:01:27,720 --> 21:01:28,720
communication we look at and presence
29295
21:01:30,360 --> 21:01:31,360
this is a real snapshot of a pretty huge
29296
21:01:34,976 --> 21:01:35,976
subject area so as with a lot of network
29297
21:01:39,120 --> 21:01:40,120
plus stuff especially the new stuff in
29298
21:01:41,280 --> 21:01:42,280
the syllabus you just expect it to have
29299
21:01:43,320 --> 21:01:44,320
an awareness of it
29300
21:01:45,536 --> 21:01:46,536
you see is the integration of a whole
29301
21:01:48,240 --> 21:01:49,240
bunch of communication
29302
21:01:50,240 --> 21:01:51,240
methods including voice video and data
29303
21:01:53,696 --> 21:01:54,696
all goes into your IP network which is
29304
21:01:56,464 --> 21:01:57,464
kind of tied in with the cloud now and
29305
21:01:59,216 --> 21:02:00,216
how everything would be you'd expect
29306
21:02:00,896 --> 21:02:01,896
everything to be working over IP
29307
21:02:03,480 --> 21:02:04,480
and over multiple devices depending on
29308
21:02:06,296 --> 21:02:07,296
where you are and how you want things to
29309
21:02:08,104 --> 21:02:09,104
work
29310
21:02:09,120 --> 21:02:10,120
the idea is it simplifies real-time
29311
21:02:11,360 --> 21:02:12,360
Communications at an Enterprise level
29312
21:02:15,240 --> 21:02:16,240
including it can work it doesn't have to
29313
21:02:18,000 --> 21:02:19,000
be Enterprise by the way it can be any
29314
21:02:19,504 --> 21:02:20,504
small Network including homes
29315
21:02:21,832 --> 21:02:22,832
making calls instant messages having a
29316
21:02:24,896 --> 21:02:25,896
video or audio conference sharing your
29317
21:02:28,144 --> 21:02:29,144
desktop with whoever needs to log in and
29318
21:02:30,240 --> 21:02:31,240
troubleshoot
29319
21:02:31,920 --> 21:02:32,920
presence information
29320
21:02:34,744 --> 21:02:35,744
so you see it's all forms of
29321
21:02:37,336 --> 21:02:38,336
communications are exchanged over IP
29322
21:02:41,240 --> 21:02:42,240
integrates real-time Communications with
29323
21:02:44,104 --> 21:02:45,104
non-real time such as accessing your
29324
21:02:46,744 --> 21:02:47,744
voicemail if you're not available
29325
21:02:48,256 --> 21:02:49,256
accessing your email text messages
29326
21:02:51,920 --> 21:02:52,920
faxes I don't even know who uses those
29327
21:02:54,424 --> 21:02:55,424
now
29328
21:02:56,104 --> 21:02:57,104
it allows you to send messages on one
29329
21:02:58,440 --> 21:02:59,440
medium but receive a response to another
29330
21:03:00,256 --> 21:03:01,256
an example is when you send somebody a
29331
21:03:02,872 --> 21:03:03,872
voicemail you've probably had this
29332
21:03:04,376 --> 21:03:05,376
happen before or you've left a voicemail
29333
21:03:06,536 --> 21:03:07,536
and it says it will send the user a text
29334
21:03:08,696 --> 21:03:09,696
or email
29335
21:03:11,160 --> 21:03:12,160
you can retrieve
29336
21:03:13,320 --> 21:03:14,320
um check and retrieve emails or
29337
21:03:15,120 --> 21:03:16,120
voicemails using any Communications at
29338
21:03:17,040 --> 21:03:18,040
any time
29339
21:03:18,176 --> 21:03:19,176
our presence is a component of UC shows
29340
21:03:22,016 --> 21:03:23,016
the present status of a user in real
29341
21:03:23,872 --> 21:03:24,872
time whether they are available and
29342
21:03:26,280 --> 21:03:27,280
available where they are located if if
29343
21:03:28,552 --> 21:03:29,552
you've enabled geoip tracking
29344
21:03:31,920 --> 21:03:32,920
or Geo tracking sorry
29345
21:03:34,920 --> 21:03:35,920
allows users to communicate seamlessly
29346
21:03:37,144 --> 21:03:38,144
even if they're in different locations
29347
21:03:39,192 --> 21:03:40,192
you can look at a person by accessing an
29348
21:03:42,360 --> 21:03:43,360
interactive directory and engaging
29349
21:03:44,872 --> 21:03:45,872
communication through text voice or
29350
21:03:47,512 --> 21:03:48,512
video
29351
21:03:48,896 --> 21:03:49,896
so that's the summary of what we've
29352
21:03:50,464 --> 21:03:51,464
covered just wanted to go and show you
29353
21:03:52,440 --> 21:03:53,440
just for more
29354
21:03:53,896 --> 21:03:54,896
context really Cisco's unified
29355
21:03:56,760 --> 21:03:57,760
Communications
29356
21:03:58,552 --> 21:03:59,552
I'm just going to play a video this
29357
21:04:00,656 --> 21:04:01,656
video is copyright Cisco system so if
29358
21:04:02,824 --> 21:04:03,824
you want to learn more
29359
21:04:04,920 --> 21:04:05,920
um all you do is go to Cisco or in fact
29360
21:04:07,144 --> 21:04:08,144
type Cisco unified Communications
29361
21:04:10,976 --> 21:04:11,976
I'll just put a video on now
29362
21:04:14,216 --> 21:04:15,216
foreign
29363
21:06:28,860 --> 21:06:29,860
[Music]
29364
21:06:37,576 --> 21:06:38,576
thank you
29365
21:06:44,576 --> 21:06:45,576
welcome to module 17 lesson one
29366
21:06:47,040 --> 21:06:48,040
introduction to virtualization this is
29367
21:06:49,744 --> 21:06:50,744
one of the few new topics that have been
29368
21:06:52,680 --> 21:06:53,680
added to the syllabus
29369
21:06:54,424 --> 21:06:55,424
surrounding virtualization and cloud
29370
21:06:57,120 --> 21:06:58,120
computing
29371
21:06:59,360 --> 21:07:00,360
and come to your offer a cloud
29372
21:07:01,856 --> 21:07:02,856
certification actually there's a cloud
29373
21:07:04,320 --> 21:07:05,320
Essentials and I think there might be a
29374
21:07:06,120 --> 21:07:07,120
cloud Plus
29375
21:07:07,680 --> 21:07:08,680
definitely a cloud Essentials because we
29376
21:07:09,720 --> 21:07:10,720
host uh host that course
29377
21:07:12,424 --> 21:07:13,424
all right module objective is the
29378
21:07:14,104 --> 21:07:15,104
definition of virtualization what is a
29379
21:07:16,192 --> 21:07:17,192
virtual machine and the software
29380
21:07:19,144 --> 21:07:20,144
I'm sure you've heard of it actually
29381
21:07:20,400 --> 21:07:21,400
it's the new or one of the very new and
29382
21:07:22,616 --> 21:07:23,616
exciting emerging Technologies that's
29383
21:07:26,104 --> 21:07:27,104
made alive a lot easier for Network
29384
21:07:27,720 --> 21:07:28,720
engineers
29385
21:07:30,296 --> 21:07:31,296
um companies from a financial and
29386
21:07:33,120 --> 21:07:34,120
operations standpoint and also home
29387
21:07:35,872 --> 21:07:36,872
users who can do a lot more interesting
29388
21:07:37,856 --> 21:07:38,856
things on their
29389
21:07:39,720 --> 21:07:40,720
um systems at home
29390
21:07:41,936 --> 21:07:42,936
so it refers to the technologies that
29391
21:07:43,976 --> 21:07:44,976
allow a single physical computer or or
29392
21:07:46,496 --> 21:07:47,496
server obviously environment to operate
29393
21:07:49,256 --> 21:07:50,256
as multiple virtual machines
29394
21:07:50,760 --> 21:07:51,760
simultaneously transforms the physical
29395
21:07:53,464 --> 21:07:54,464
Hardware resources into virtual Hardware
29396
21:07:55,976 --> 21:07:56,976
resources
29397
21:07:57,536 --> 21:07:58,536
so what you normally have one device
29398
21:07:59,824 --> 21:08:00,824
running one operating system you can
29399
21:08:02,160 --> 21:08:03,160
have depending on how much Hardware you
29400
21:08:04,144 --> 21:08:05,144
have and how you apportion it and two or
29401
21:08:07,320 --> 21:08:08,320
more virtual machines
29402
21:08:10,376 --> 21:08:11,376
a virtual machine is an isolated
29403
21:08:12,360 --> 21:08:13,360
software replica of the original
29404
21:08:13,920 --> 21:08:14,920
computer so for all intents and purposes
29405
21:08:16,680 --> 21:08:17,680
it appears as a machine in its own right
29406
21:08:20,160 --> 21:08:21,160
with all processor instructions and
29407
21:08:22,744 --> 21:08:23,744
system resources
29408
21:08:24,600 --> 21:08:25,600
so you'll often see an image like this
29409
21:08:27,240 --> 21:08:28,240
where you have a physical computer or
29410
21:08:28,920 --> 21:08:29,920
server and inside and it will represent
29411
21:08:32,280 --> 21:08:33,280
a number of virtual machines
29412
21:08:35,696 --> 21:08:36,696
much in the same way as their vlans they
29413
21:08:37,976 --> 21:08:38,976
operate in their own right
29414
21:08:40,552 --> 21:08:41,552
as if they're an actual machine
29415
21:08:43,976 --> 21:08:44,976
a virtual machines are completely
29416
21:08:45,536 --> 21:08:46,536
separate and independent
29417
21:08:49,016 --> 21:08:50,016
by running good operating system in each
29418
21:08:50,936 --> 21:08:51,936
one it becomes possible to run several
29419
21:08:52,800 --> 21:08:53,800
guest operating systems at the same time
29420
21:08:54,656 --> 21:08:55,656
so you could have
29421
21:08:56,872 --> 21:08:57,872
um a Microsoft Linux and other operating
29422
21:09:01,016 --> 21:09:02,016
systems running on the same physical
29423
21:09:03,056 --> 21:09:04,056
device but different virtual devices
29424
21:09:07,320 --> 21:09:08,320
a whole bunch of virtualization software
29425
21:09:09,600 --> 21:09:10,600
around some free some um you have to pay
29426
21:09:12,720 --> 21:09:13,720
for and you get different levels of
29427
21:09:15,176 --> 21:09:16,176
um
29428
21:09:15,784 --> 21:09:16,784
software up to Enterprise and obviously
29429
21:09:18,240 --> 21:09:19,240
support contracts
29430
21:09:19,856 --> 21:09:20,856
the software transforms the hardware of
29431
21:09:22,144 --> 21:09:23,144
the computer including the CPU memory
29432
21:09:23,872 --> 21:09:24,872
Network adapting to Virtual resources
29433
21:09:26,696 --> 21:09:27,696
these are shared amongst virtual
29434
21:09:28,680 --> 21:09:29,680
machines
29435
21:09:31,016 --> 21:09:32,016
it basically provides a layer of layer
29436
21:09:33,600 --> 21:09:34,600
of abstraction so for all intents and
29437
21:09:35,936 --> 21:09:36,936
purposes there's a divide a virtual
29438
21:09:38,280 --> 21:09:39,280
divide between all of these different
29439
21:09:39,784 --> 21:09:40,784
machines
29440
21:09:42,832 --> 21:09:43,832
the labor of abstraction is basically
29441
21:09:44,872 --> 21:09:45,872
there to hide what's happening
29442
21:09:46,440 --> 21:09:47,440
underneath what you can see
29443
21:09:49,256 --> 21:09:50,256
foreign
29444
21:09:51,056 --> 21:09:52,056
as a result the abstraction provided by
29445
21:09:53,400 --> 21:09:54,400
the software the guest operating systems
29446
21:09:55,800 --> 21:09:56,800
are not tied to the underlying physical
29447
21:09:57,656 --> 21:09:58,656
Hardware so this is how we can actually
29448
21:09:59,400 --> 21:10:00,400
get it all to run
29449
21:10:03,896 --> 21:10:04,896
so you have a portability of moving
29450
21:10:05,696 --> 21:10:06,696
virtual machines from one physical
29451
21:10:07,080 --> 21:10:08,080
computer to another physical computer if
29452
21:10:09,720 --> 21:10:10,720
you so wish great if you want to do
29453
21:10:12,120 --> 21:10:13,120
testing interoperability stress testing
29454
21:10:15,240 --> 21:10:16,240
or just practicing even if you want to
29455
21:10:18,056 --> 21:10:19,056
do some install various operating
29456
21:10:20,512 --> 21:10:21,512
systems onto one device in order to
29457
21:10:23,280 --> 21:10:24,280
practice free exams or job interviews
29458
21:10:26,400 --> 21:10:27,400
so this is just an overview we've got
29459
21:10:28,376 --> 21:10:29,376
more to cover in the following
29460
21:10:29,936 --> 21:10:30,936
presentations what is virtualization the
29461
21:10:33,176 --> 21:10:34,176
virtual machine the software that's all
29462
21:10:35,640 --> 21:10:36,640
for now thanks for watching
29463
21:10:42,000 --> 21:10:43,000
[Music]
29464
21:10:57,896 --> 21:10:58,896
welcome to module 17 lesson 2
29465
21:11:00,504 --> 21:11:01,504
virtualization components and
29466
21:11:02,760 --> 21:11:03,760
software-defined networking or sdn
29467
21:11:06,176 --> 21:11:07,176
for short
29468
21:11:08,216 --> 21:11:09,216
looking at virtual networking virtual
29469
21:11:10,552 --> 21:11:11,552
network adapters a virtual switch
29470
21:11:13,680 --> 21:11:14,680
Virtual Router
29471
21:11:16,552 --> 21:11:17,552
Virtual Router via vrrp
29472
21:11:20,336 --> 21:11:21,336
the virtual firewall and sdn
29473
21:11:24,296 --> 21:11:25,296
and while we why would want to use sdn
29474
21:11:29,336 --> 21:11:30,336
so a virtual network is a system in
29475
21:11:31,440 --> 21:11:32,440
which the following is true you've got
29476
21:11:33,296 --> 21:11:34,296
two or more virtual machines connected
29477
21:11:35,160 --> 21:11:36,160
logically to one another they could each
29478
21:11:37,800 --> 21:11:38,800
just send received data as if they were
29479
21:11:40,616 --> 21:11:41,616
operating as physical devices
29480
21:11:44,104 --> 21:11:45,104
I've got an example here esxi which is
29481
21:11:47,040 --> 21:11:48,040
software available from VMware I think
29482
21:11:50,464 --> 21:11:51,464
they do offer some free software I
29483
21:11:52,320 --> 21:11:53,320
haven't checked as to which
29484
21:11:54,784 --> 21:11:55,784
um is free for home use or commercial
29485
21:11:57,656 --> 21:11:58,656
use and I recommend you check out the
29486
21:12:01,376 --> 21:12:02,376
VMware certifications on
29487
21:12:03,480 --> 21:12:04,480
howturnetwork.com
29488
21:12:06,120 --> 21:12:07,120
they're very relevant for modern day
29489
21:12:08,464 --> 21:12:09,464
networking
29490
21:12:10,256 --> 21:12:11,256
so they can send to receive data from
29491
21:12:12,656 --> 21:12:13,656
each other the virtual network adapter
29492
21:12:15,000 --> 21:12:16,000
is a software implementation of a
29493
21:12:16,920 --> 21:12:17,920
physical network adapter which I'm sure
29494
21:12:18,960 --> 21:12:19,960
comes as no surprise
29495
21:12:20,640 --> 21:12:21,640
so you have a physical adapter but the
29496
21:12:22,616 --> 21:12:23,616
virtual one is acting in exactly the
29497
21:12:24,656 --> 21:12:25,656
same mother and same manner sorry
29498
21:12:27,720 --> 21:12:28,720
and you've got a diagram here of a
29499
21:12:30,296 --> 21:12:31,296
physical network card
29500
21:12:32,824 --> 21:12:33,824
um and then you're working as a subset
29501
21:12:36,000 --> 21:12:37,000
of this is your virtual machine they're
29502
21:12:38,160 --> 21:12:39,160
running virtual network cards and
29503
21:12:40,744 --> 21:12:41,744
virtual machines on top of that
29504
21:12:42,896 --> 21:12:43,896
the virtual network card interface is a
29505
21:12:45,240 --> 21:12:46,240
virtual machine to the network they can
29506
21:12:47,824 --> 21:12:48,824
have one or more virtual Nic next or
29507
21:12:51,600 --> 21:12:52,600
v-nix
29508
21:12:53,160 --> 21:12:54,160
eat such Phoenix has its own Mac address
29509
21:12:55,320 --> 21:12:56,320
it needs to follow the same rules as
29510
21:12:56,936 --> 21:12:57,936
physical networking so it'll need to
29511
21:12:58,496 --> 21:12:59,496
have a unique Mac
29512
21:13:00,120 --> 21:13:01,120
a virtual network card in a um virtual
29513
21:13:04,080 --> 21:13:05,080
machine you still have to configure it
29514
21:13:06,120 --> 21:13:07,120
all the same rules apply it's just the
29515
21:13:08,400 --> 21:13:09,400
fact that it isn't operating uh
29516
21:13:10,376 --> 21:13:11,376
physically
29517
21:13:11,576 --> 21:13:12,576
so you can go and see and physically
29518
21:13:13,504 --> 21:13:14,504
plug and unplug cables
29519
21:13:15,784 --> 21:13:16,784
virtual switch or v-switch is a software
29520
21:13:18,360 --> 21:13:19,360
version of a physical switch it's got
29521
21:13:21,120 --> 21:13:22,120
Network ports similar to the RJ45
29522
21:13:23,576 --> 21:13:24,576
connectors you have and one
29523
21:13:27,016 --> 21:13:28,016
1016 virtual ports this all depends on
29524
21:13:30,000 --> 21:13:31,000
your software and Hardware platform
29525
21:13:31,616 --> 21:13:32,616
you're putting it on there's a limit of
29526
21:13:34,640 --> 21:13:35,640
4088 ports on all virtual switches on
29527
21:13:38,216 --> 21:13:39,216
the VMware esxi host
29528
21:13:40,920 --> 21:13:41,920
different vendors May well have
29529
21:13:43,192 --> 21:13:44,192
different um capabilities and rules to
29530
21:13:46,616 --> 21:13:47,616
follow
29531
21:13:47,824 --> 21:13:48,824
a virtual send switch can send Network
29532
21:13:50,936 --> 21:13:51,936
traffic between virtual machines on the
29533
21:13:52,856 --> 21:13:53,856
same host or from virtual machines to an
29534
21:13:55,192 --> 21:13:56,192
external network that's outside the
29535
21:13:57,240 --> 21:13:58,240
virtual virtualized hosts you can go to
29536
21:14:00,784 --> 21:14:01,784
YouTube and check on videos on how to
29537
21:14:02,512 --> 21:14:03,512
check a virtual air device to a live
29538
21:14:06,296 --> 21:14:07,296
Network and a lot of the time you do it
29539
21:14:08,872 --> 21:14:09,872
for home use to overcome
29540
21:14:11,400 --> 21:14:12,400
um limitations when you're trying to get
29541
21:14:13,744 --> 21:14:14,744
different bits of software and Hardware
29542
21:14:15,120 --> 21:14:16,120
to work for certification exams it's
29543
21:14:18,360 --> 21:14:19,360
quite common
29544
21:14:19,800 --> 21:14:20,800
virtual switch joins the network with a
29545
21:14:21,960 --> 21:14:22,960
physical Network when it when it
29546
21:14:23,336 --> 21:14:24,336
connects to a physical switch using um
29547
21:14:26,216 --> 21:14:27,216
physical network adapters
29548
21:14:28,920 --> 21:14:29,920
uh you can also get virtual routers a
29549
21:14:31,440 --> 21:14:32,440
software version of a physical router
29550
21:14:33,240 --> 21:14:34,240
obviously performs your layer 3 packet
29551
21:14:35,640 --> 21:14:36,640
forward in between
29552
21:14:37,464 --> 21:14:38,464
your subnets or lands and um vlans
29553
21:14:42,896 --> 21:14:43,896
obviously you need layer three
29554
21:14:45,360 --> 21:14:46,360
capability of some sort a virtual router
29555
21:14:48,720 --> 21:14:49,720
via vrrp which we covered that protocol
29556
21:14:51,240 --> 21:14:52,240
earlier
29557
21:14:52,376 --> 21:14:53,376
uh it's a virtual route is implemented
29558
21:14:55,144 --> 21:14:56,144
when you use vrp to provide redundancy
29559
21:14:58,256 --> 21:14:59,256
of the default gateway so all the hosts
29560
21:15:00,536 --> 21:15:01,536
still have IP connectivity
29561
21:15:03,600 --> 21:15:04,600
it's back by two or more physical
29562
21:15:04,976 --> 21:15:05,976
routers depending on the protocol you
29563
21:15:07,016 --> 21:15:08,016
can have two or three
29564
21:15:09,120 --> 21:15:10,120
I'm not sure what the limit is actually
29565
21:15:10,800 --> 21:15:11,800
depends on the protocol and it does
29566
21:15:12,896 --> 21:15:13,896
change
29567
21:15:15,240 --> 21:15:16,240
uh why use a Virtual Router provides the
29568
21:15:18,000 --> 21:15:19,000
same routing function functionality but
29569
21:15:20,936 --> 21:15:21,936
it's virtual so you've got all the
29570
21:15:22,192 --> 21:15:23,192
advantages of costs
29571
21:15:24,744 --> 21:15:25,744
uh virtual firewalls they're mentioned
29572
21:15:28,256 --> 21:15:29,256
again in the Cisco syllabus probably
29573
21:15:30,832 --> 21:15:31,832
definitely the CCNA routing briefly but
29574
21:15:34,016 --> 21:15:35,016
I would imagine in the CCNA Security in
29575
21:15:36,120 --> 21:15:37,120
a lot more detail
29576
21:15:37,440 --> 21:15:38,440
so it's a virtual version of an actual
29577
21:15:39,296 --> 21:15:40,296
firewall
29578
21:15:40,496 --> 21:15:41,496
so they're implemented as a follower
29579
21:15:42,176 --> 21:15:43,176
within a virtual machine or as an
29580
21:15:44,400 --> 21:15:45,400
appliance it provides security to your
29581
21:15:46,376 --> 21:15:47,376
virtual environment
29582
21:15:48,720 --> 21:15:49,720
does exactly the same job as a hardware
29583
21:15:51,176 --> 21:15:52,176
firewall
29584
21:15:53,280 --> 21:15:54,280
just moving on to sdn now it's um
29585
21:15:57,296 --> 21:15:58,296
a big topic and it's been introduced
29586
21:15:59,696 --> 21:16:00,696
into the new Cisco CCNA exam and I would
29587
21:16:03,832 --> 21:16:04,832
imagine
29588
21:16:04,800 --> 21:16:05,800
um
29589
21:16:05,464 --> 21:16:06,464
it's going to have more and more
29590
21:16:06,832 --> 21:16:07,832
prominence over the years to come
29591
21:16:08,040 --> 21:16:09,040
because Cisco have invested heavily in
29592
21:16:11,160 --> 21:16:12,160
sdn and there's a lot of um some Open
29593
21:16:14,400 --> 21:16:15,400
Standards that have had a huge uptake as
29594
21:16:16,976 --> 21:16:17,976
well
29595
21:16:18,176 --> 21:16:19,176
it provides um a high level
29596
21:16:20,696 --> 21:16:21,696
Administration capability to network
29597
21:16:23,400 --> 21:16:24,400
admins it allows you to manage your
29598
21:16:26,104 --> 21:16:27,104
entire network through a user interface
29599
21:16:28,320 --> 21:16:29,320
that abstracts a com complexity so you
29600
21:16:32,400 --> 21:16:33,400
wouldn't necessarily need to understand
29601
21:16:33,960 --> 21:16:34,960
all the underlying commands that have
29602
21:16:35,936 --> 21:16:36,936
been executed and how it all works
29603
21:16:40,256 --> 21:16:41,256
um just to manage it if you're using sdn
29604
21:16:43,144 --> 21:16:44,144
obviously it helps if you to be a
29605
21:16:45,120 --> 21:16:46,120
network engineer that you actually
29606
21:16:46,256 --> 21:16:47,256
understand what's happening
29607
21:16:47,872 --> 21:16:48,872
but um now I suppose it's like managing
29608
21:16:51,424 --> 21:16:52,424
your car
29609
21:16:52,496 --> 21:16:53,496
they've got all these different settings
29610
21:16:53,872 --> 21:16:54,872
on the onboard computers that change
29611
21:16:56,160 --> 21:16:57,160
your handling and your engine
29612
21:16:58,256 --> 21:16:59,256
performance and all that kind of thing
29613
21:17:00,056 --> 21:17:01,056
you can turn different controls on or
29614
21:17:02,512 --> 21:17:03,512
off like traction control and you don't
29615
21:17:05,400 --> 21:17:06,400
necessarily need to worry about how it
29616
21:17:07,144 --> 21:17:08,144
all works
29617
21:17:11,216 --> 21:17:12,216
all right sdns are used to control the
29618
21:17:13,504 --> 21:17:14,504
operation and network devices
29619
21:17:15,896 --> 21:17:16,896
um look into more I think Cisco I'm not
29620
21:17:19,440 --> 21:17:20,440
sure which CCNA version maybe data
29621
21:17:22,016 --> 21:17:23,016
center that looks interesting any more
29622
21:17:24,000 --> 21:17:25,000
details but there's a whole bunch of um
29623
21:17:26,696 --> 21:17:27,696
controls and formats that have to manage
29624
21:17:29,760 --> 21:17:30,760
your
29625
21:17:31,320 --> 21:17:32,320
um interface between your network the
29626
21:17:34,496 --> 21:17:35,496
user and all of your devices and apis to
29627
21:17:38,400 --> 21:17:39,400
name one
29628
21:17:40,376 --> 21:17:41,376
so examples of sdns or Cisco open
29629
21:17:43,080 --> 21:17:44,080
network environments
29630
21:17:44,784 --> 21:17:45,784
nikira's Network virtualization platform
29631
21:17:47,360 --> 21:17:48,360
why bother it basically makes your life
29632
21:17:50,464 --> 21:17:51,464
a lot easier as the network
29633
21:17:51,784 --> 21:17:52,784
administrator you can interact with your
29634
21:17:54,360 --> 21:17:55,360
entire network without having to
29635
21:17:56,400 --> 21:17:57,400
actually connect via telnet or
29636
21:17:59,400 --> 21:18:00,400
physically connect to your devices or
29637
21:18:01,616 --> 21:18:02,616
even understand all of the different
29638
21:18:03,656 --> 21:18:04,656
commands so if you're using
29639
21:18:06,376 --> 21:18:07,376
Juniper Hardware it's got one type of
29640
21:18:09,784 --> 21:18:10,784
um
29641
21:18:10,976 --> 21:18:11,976
command line interface for um copyright
29642
21:18:14,280 --> 21:18:15,280
reasons your Huawei and Cisco all got
29643
21:18:19,680 --> 21:18:20,680
different command lines different
29644
21:18:21,120 --> 21:18:22,120
commands all to achieve the same thing
29645
21:18:23,160 --> 21:18:24,160
so you don't you don't need to worry
29646
21:18:24,480 --> 21:18:25,480
about that if you're using SDM
29647
21:18:27,480 --> 21:18:28,480
so get get rid of the command line some
29648
21:18:30,536 --> 21:18:31,536
of the benefits again the graphical user
29649
21:18:32,936 --> 21:18:33,936
interface provides information about
29650
21:18:35,040 --> 21:18:36,040
what's going on with your network
29651
21:18:37,504 --> 21:18:38,504
it allows you to specify changes and
29652
21:18:40,256 --> 21:18:41,256
behind the scenes the actual
29653
21:18:41,400 --> 21:18:42,400
configurations are done with the
29654
21:18:43,192 --> 21:18:44,192
interface one of the apis between the
29655
21:18:45,896 --> 21:18:46,896
software and the hardware
29656
21:18:48,720 --> 21:18:49,720
all right so it's just an overview
29657
21:18:50,216 --> 21:18:51,216
looked at virtual networking the virtual
29658
21:18:52,376 --> 21:18:53,376
adapters virtual switches and routers
29659
21:18:54,856 --> 21:18:55,856
the RRP
29660
21:18:57,240 --> 21:18:58,240
firewalls and software-defined
29661
21:18:59,216 --> 21:19:00,216
networking and why why would we be
29662
21:19:01,320 --> 21:19:02,320
interested in using it
29663
21:19:03,000 --> 21:19:04,000
so that's all thanks for watching
29664
21:19:09,870 --> 21:19:10,870
[Music]
29665
21:19:25,856 --> 21:19:26,856
welcome to module 17 lesson 3 the
29666
21:19:28,976 --> 21:19:29,976
storage area network
29667
21:19:31,504 --> 21:19:32,504
I think come to your actually have a
29668
21:19:34,256 --> 21:19:35,256
qualification uh storage area networking
29669
21:19:37,016 --> 21:19:38,016
engineer Plus
29670
21:19:38,760 --> 21:19:39,760
and we actually have um such a course on
29671
21:19:42,120 --> 21:19:43,120
howturnetwork.com this is just an
29672
21:19:44,696 --> 21:19:45,696
overview touching on some of the
29673
21:19:46,552 --> 21:19:47,552
subjects they mentioned in the exam
29674
21:19:49,920 --> 21:19:50,920
syllabus
29675
21:19:53,280 --> 21:19:54,280
looking at storage area networks direct
29676
21:19:56,000 --> 21:19:57,000
attached storage network attached
29677
21:19:58,856 --> 21:19:59,856
storage
29678
21:20:00,256 --> 21:20:01,256
sanvi Das
29679
21:20:03,424 --> 21:20:04,424
Sun media
29680
21:20:05,280 --> 21:20:06,280
fiber channel
29681
21:20:06,856 --> 21:20:07,856
iSCSI San
29682
21:20:09,240 --> 21:20:10,240
Jose architecture and components of
29683
21:20:12,120 --> 21:20:13,120
voice guzzy also jumbo frames
29684
21:20:15,240 --> 21:20:16,240
Sun as we already know stands for
29685
21:20:17,104 --> 21:20:18,104
storage area network it's a high speed
29686
21:20:19,320 --> 21:20:20,320
Network the idea is it allows
29687
21:20:22,376 --> 21:20:23,376
um transfer between the computer systems
29688
21:20:24,176 --> 21:20:25,176
and the storage devices it's optimized
29689
21:20:26,872 --> 21:20:27,872
for this type of Technology as well
29690
21:20:29,936 --> 21:20:30,936
we'll see this as we go along
29691
21:20:31,976 --> 21:20:32,976
and here's an example which will um
29692
21:20:35,040 --> 21:20:36,040
you'll see in a few slides
29693
21:20:38,216 --> 21:20:39,216
so why bother at all why do we need a
29694
21:20:40,144 --> 21:20:41,144
storage area network again everything
29695
21:20:42,960 --> 21:20:43,960
covered really in the network plus was
29696
21:20:45,120 --> 21:20:46,120
created in order to solve some specific
29697
21:20:48,656 --> 21:20:49,656
or general networking problem
29698
21:20:51,240 --> 21:20:52,240
it's the evolution in data storage
29699
21:20:53,104 --> 21:20:54,104
technology and we'll look at some Legacy
29700
21:20:55,192 --> 21:20:56,192
ideas in a moment
29701
21:20:57,784 --> 21:20:58,784
so um unfortunately this I'll put the
29702
21:21:00,832 --> 21:21:01,832
wrong order here so the lines are
29703
21:21:02,160 --> 21:21:03,160
appearing in the wrong order there's
29704
21:21:03,832 --> 21:21:04,832
been progress in the data storage
29705
21:21:05,160 --> 21:21:06,160
technology from Das to Sam direct
29706
21:21:09,360 --> 21:21:10,360
attached storage is the traditional
29707
21:21:12,480 --> 21:21:13,480
way and it's I'm sure many companies
29708
21:21:15,240 --> 21:21:16,240
still use it those who don't use uh San
29709
21:21:18,120 --> 21:21:19,120
as a solution for storage
29710
21:21:20,464 --> 21:21:21,464
so a traditional client server systems
29711
21:21:22,800 --> 21:21:23,800
each sort of server having its own
29712
21:21:24,832 --> 21:21:25,832
storage and the storage is directly
29713
21:21:27,360 --> 21:21:28,360
attached to the server internally
29714
21:21:29,640 --> 21:21:30,640
usually or it could be external
29715
21:21:32,696 --> 21:21:33,696
search
29716
21:21:34,216 --> 21:21:35,216
a technology is referred to as direct
29717
21:21:37,192 --> 21:21:38,192
attached storage or Das
29718
21:21:40,016 --> 21:21:41,016
so there obviously has to be advantages
29719
21:21:42,000 --> 21:21:43,000
it's high speed and it's exclusive
29720
21:21:44,104 --> 21:21:45,104
access to the storage so it's not shared
29721
21:21:48,360 --> 21:21:49,360
preferred by small companies just
29722
21:21:50,640 --> 21:21:51,640
cheaper to implement easier to implement
29723
21:21:53,000 --> 21:21:54,000
easier to um
29724
21:21:55,504 --> 21:21:56,504
troubleshoot maintain
29725
21:21:58,440 --> 21:21:59,440
obviously there are disadvantages which
29726
21:22:00,424 --> 21:22:01,424
is why it's been
29727
21:22:02,400 --> 21:22:03,400
um
29728
21:22:03,056 --> 21:22:04,056
superseded by many companies so what you
29729
21:22:06,360 --> 21:22:07,360
get is a pocket of isolated storage it's
29730
21:22:08,464 --> 21:22:09,464
not officially utilized and this ties
29731
21:22:11,576 --> 21:22:12,576
into virtualization really where you
29732
21:22:13,616 --> 21:22:14,616
we've got this whole amount of resources
29733
21:22:16,144 --> 21:22:17,144
but we may only be using a certain
29734
21:22:17,936 --> 21:22:18,936
percentage of it which is a waste
29735
21:22:21,320 --> 21:22:22,320
so for example when one server has
29736
21:22:23,640 --> 21:22:24,640
plenty of C uh free storage and the
29737
21:22:25,744 --> 21:22:26,744
other one has almost ran out of space
29738
21:22:27,240 --> 21:22:28,240
then we've got a disparity
29739
21:22:29,936 --> 21:22:30,936
this is where um Network attaches
29740
21:22:32,160 --> 21:22:33,160
storage will help direct attached
29741
21:22:34,320 --> 21:22:35,320
storage design doesn't allow the free
29742
21:22:36,240 --> 21:22:37,240
capacity of the servers to be shared
29743
21:22:39,960 --> 21:22:40,960
so when a business deploys more servers
29744
21:22:42,240 --> 21:22:43,240
in the network the following occurs
29745
21:22:44,640 --> 21:22:45,640
there's an increase in the wastage
29746
21:22:46,192 --> 21:22:47,192
increase in the complexity of managing
29747
21:22:48,720 --> 21:22:49,720
all of these isolated storage because
29748
21:22:51,056 --> 21:22:52,056
usually you've got raid so you've got to
29749
21:22:53,104 --> 21:22:54,104
insert and pull out various disks
29750
21:22:57,120 --> 21:22:58,120
and network attached storage another
29751
21:22:59,160 --> 21:23:00,160
image there it decouples the storage
29752
21:23:01,680 --> 21:23:02,680
from the servers so the servers are
29753
21:23:03,600 --> 21:23:04,600
still there but we um remove the storage
29754
21:23:06,536 --> 21:23:07,536
as another feature makes the storage a
29755
21:23:10,856 --> 21:23:11,856
centralized pool of shed devices that
29756
21:23:13,976 --> 21:23:14,976
can be accessed by all the servers
29757
21:23:15,480 --> 21:23:16,480
connected to the network
29758
21:23:18,784 --> 21:23:19,784
now network attached storage is not a
29759
21:23:20,464 --> 21:23:21,464
network in its own right but a storage
29760
21:23:22,016 --> 21:23:23,016
array hooked up to an existing Network
29761
21:23:26,464 --> 21:23:27,464
here's an example of a Nas server
29762
21:23:29,160 --> 21:23:30,160
that's a Netgear by looks of it it can
29763
21:23:31,800 --> 21:23:32,800
provide centralized
29764
21:23:33,176 --> 21:23:34,176
um shared stories of terabytes of
29765
21:23:34,976 --> 21:23:35,976
storage you get enough servers for home
29766
21:23:37,616 --> 21:23:38,616
users as well wherever everyone can
29767
21:23:39,536 --> 21:23:40,536
connect to this particular device and
29768
21:23:42,360 --> 21:23:43,360
hopefully that device then in turn backs
29769
21:23:44,576 --> 21:23:45,576
up somewhere over to the cloud or
29770
21:23:46,920 --> 21:23:47,920
somewhere like that disadvantage is
29771
21:23:49,920 --> 21:23:50,920
doesn't provide the high speed data
29772
21:23:52,016 --> 21:23:53,016
protection needed in Enterprise
29773
21:23:53,400 --> 21:23:54,400
environments because it typically sits
29774
21:23:55,744 --> 21:23:56,744
on an existing shed corporate Network
29775
21:23:59,872 --> 21:24:00,872
um complete data backup takes a lot of
29776
21:24:02,400 --> 21:24:03,400
time and obviously takes up a lot of
29777
21:24:04,080 --> 21:24:05,080
bandwidth
29778
21:24:06,192 --> 21:24:07,192
so sun is a dedicated Network that
29779
21:24:08,824 --> 21:24:09,824
transfers blocks of data at a high speed
29780
21:24:10,552 --> 21:24:11,552
to a storage device
29781
21:24:12,960 --> 21:24:13,960
a low latency for the input output
29782
21:24:15,360 --> 21:24:16,360
request to the storage device
29783
21:24:21,176 --> 21:24:22,176
uh what you what sound gives you is
29784
21:24:23,760 --> 21:24:24,760
access to several servers that connect
29785
21:24:26,216 --> 21:24:27,216
to several several storage devices you
29786
21:24:28,616 --> 21:24:29,616
can see we've got a in this instance
29787
21:24:30,720 --> 21:24:31,720
we've got a full mesh connection between
29788
21:24:32,872 --> 21:24:33,872
the servers the switches and the storage
29789
21:24:35,040 --> 21:24:36,040
array there
29790
21:24:38,040 --> 21:24:39,040
also allows the storage devices to
29791
21:24:40,144 --> 21:24:41,144
communicate with each other
29792
21:24:43,920 --> 21:24:44,920
limitations going back to direct access
29793
21:24:46,192 --> 21:24:47,192
storage
29794
21:24:47,936 --> 21:24:48,936
this is the challenge we have with the
29795
21:24:50,160 --> 21:24:51,160
traditional server attached storage you
29796
21:24:53,040 --> 21:24:54,040
can't satisfy the ever crease in demands
29797
21:24:54,832 --> 21:24:55,832
for storage and we obviously have more
29798
21:24:57,240 --> 21:24:58,240
and more complex information
29799
21:24:58,760 --> 21:24:59,760
including video and voice
29800
21:25:02,760 --> 21:25:03,760
not scalable due to the restrictions and
29801
21:25:04,800 --> 21:25:05,800
how many devices you can add physically
29802
21:25:07,256 --> 21:25:08,256
to
29803
21:25:08,400 --> 21:25:09,400
um servers sun is scalable so you can
29804
21:25:11,464 --> 21:25:12,464
add a lot of new devices and and without
29805
21:25:13,504 --> 21:25:14,504
having to add new servers
29806
21:25:15,720 --> 21:25:16,720
you can aggregate the devices into a
29807
21:25:19,016 --> 21:25:20,016
central pool that can be accessed by the
29808
21:25:21,120 --> 21:25:22,120
servers
29809
21:25:25,144 --> 21:25:26,144
the server attached storage doesn't
29810
21:25:27,056 --> 21:25:28,056
provide High availability because if a
29811
21:25:29,216 --> 21:25:30,216
server goes down then you lose the data
29812
21:25:30,960 --> 21:25:31,960
since the data is tied to the server
29813
21:25:34,800 --> 21:25:35,800
so obviously
29814
21:25:36,296 --> 21:25:37,296
um overcomes this problem because you
29815
21:25:38,400 --> 21:25:39,400
remove the storage from the servers if a
29816
21:25:42,424 --> 21:25:43,424
server goes down in the topology then
29817
21:25:46,016 --> 21:25:47,016
the data is still accessible so you've
29818
21:25:48,296 --> 21:25:49,296
removed that as a point of failure
29819
21:25:50,824 --> 21:25:51,824
and though the sun connects multitude of
29820
21:25:53,464 --> 21:25:54,464
servers and storage devices the
29821
21:25:55,080 --> 21:25:56,080
performance doesn't so far because the
29822
21:25:57,296 --> 21:25:58,296
network is characterized by high speed
29823
21:25:59,336 --> 21:26:00,336
and low latency you've got the best of
29824
21:26:01,616 --> 21:26:02,616
two different worlds there
29825
21:26:03,424 --> 21:26:04,424
the high speed data transfer the low
29826
21:26:05,696 --> 21:26:06,696
latency can be compared to the high
29827
21:26:08,400 --> 21:26:09,400
performance of storage directly attached
29828
21:26:10,976 --> 21:26:11,976
to a server
29829
21:26:14,824 --> 21:26:15,824
so your storage area network is a
29830
21:26:16,744 --> 21:26:17,744
dedicated Network it's scalable and
29831
21:26:18,784 --> 21:26:19,784
highly available as we've already said
29832
21:26:20,336 --> 21:26:21,336
primary purpose is providing the high
29833
21:26:22,920 --> 21:26:23,920
speed
29834
21:26:23,872 --> 21:26:24,872
and the low latency
29835
21:26:26,336 --> 21:26:27,336
Sun media it's the actual cables and
29836
21:26:29,512 --> 21:26:30,512
physical wiring
29837
21:26:30,896 --> 21:26:31,896
It's associated with the unique protocol
29838
21:26:33,360 --> 21:26:34,360
and is always managed by that protocol
29839
21:26:36,000 --> 21:26:37,000
the protocol is responsible for the
29840
21:26:37,920 --> 21:26:38,920
format and sequence of data exchange on
29841
21:26:40,080 --> 21:26:41,080
the storage area network now you're
29842
21:26:42,600 --> 21:26:43,600
almost always going to have
29843
21:26:44,464 --> 21:26:45,464
um fiber channel
29844
21:26:46,320 --> 21:26:47,320
and because of the speed requirements
29845
21:26:50,216 --> 21:26:51,216
different types of optical electrical
29846
21:26:52,376 --> 21:26:53,376
transmission meter that you cannot
29847
21:26:54,480 --> 21:26:55,480
follow that and you can have copper the
29848
21:26:56,872 --> 21:26:57,872
fibers of preferred connection type
29849
21:26:59,512 --> 21:27:00,512
uh the sounds are typically typically
29850
21:27:01,504 --> 21:27:02,504
built using fiber channel
29851
21:27:04,552 --> 21:27:05,552
uh the standards you define a high-speed
29852
21:27:06,960 --> 21:27:07,960
Network that transfer dates at around
29853
21:27:09,120 --> 21:27:10,120
two gigs per second
29854
21:27:11,760 --> 21:27:12,760
the standards also define the properties
29855
21:27:13,504 --> 21:27:14,504
of the media and how data is transmitted
29856
21:27:15,720 --> 21:27:16,720
which I mentioned earlier
29857
21:27:18,240 --> 21:27:19,240
fiber channel is a de facto standard
29858
21:27:22,552 --> 21:27:23,552
the storage area network using is built
29859
21:27:26,104 --> 21:27:27,104
using fiber channel technology is called
29860
21:27:28,144 --> 21:27:29,144
the fiber channel or FC San
29861
21:27:33,656 --> 21:27:34,656
uh the whole idea is to increase access
29862
21:27:36,296 --> 21:27:37,296
to all the data and since organizations
29863
21:27:39,120 --> 21:27:40,120
have a heterogeneous combination of
29864
21:27:41,160 --> 21:27:42,160
operating systems fiber channel was
29865
21:27:44,696 --> 21:27:45,696
um designed to cater for all of these
29866
21:27:46,616 --> 21:27:47,616
different applications and operating
29867
21:27:48,296 --> 21:27:49,296
systems
29868
21:27:51,424 --> 21:27:52,424
the fiber channels solve the fundamental
29869
21:27:53,936 --> 21:27:54,936
problem of reliably making terabytes of
29870
21:27:56,696 --> 21:27:57,696
information available to hundreds of
29871
21:27:58,376 --> 21:27:59,376
servers more than likely at the same
29872
21:28:00,656 --> 21:28:01,656
time as well so serving multiple
29873
21:28:02,464 --> 21:28:03,464
requests
29874
21:28:04,936 --> 21:28:05,936
uh while direct attached storage and
29875
21:28:07,376 --> 21:28:08,376
network attached storage may be
29876
21:28:08,696 --> 21:28:09,696
appropriate for small networks the fiber
29877
21:28:10,976 --> 21:28:11,976
channel San is used generally for large
29878
21:28:14,336 --> 21:28:15,336
storage networks and Enterprise Networks
29879
21:28:19,856 --> 21:28:20,856
um con the concept of sand isn't tied to
29880
21:28:22,440 --> 21:28:23,440
any particular technology or vendor so
29881
21:28:25,376 --> 21:28:26,376
it can be used by a multitude it can
29882
21:28:27,720 --> 21:28:28,720
also be built using other Technologies
29883
21:28:29,512 --> 21:28:30,512
such
29884
21:28:30,784 --> 21:28:31,784
um as Internet Security or iSCSI
29885
21:28:35,120 --> 21:28:36,120
is a storage area network implemented
29886
21:28:37,744 --> 21:28:38,744
over an IP and it uses the iSCSI
29887
21:28:40,376 --> 21:28:41,376
protocol
29888
21:28:43,744 --> 21:28:44,744
it's a mapping of the scuzzy protocol
29889
21:28:45,960 --> 21:28:46,960
over TCP not sure if there's an RFC for
29890
21:28:49,376 --> 21:28:50,376
this actually but you can Google the ice
29891
21:28:51,832 --> 21:28:52,832
cozy for yourself and see um where the
29892
21:28:54,896 --> 21:28:55,896
proposal started
29893
21:28:57,120 --> 21:28:58,120
carries Block Level data over the IP
29894
21:28:59,464 --> 21:29:00,464
network and block storage can be
29895
21:29:01,856 --> 21:29:02,856
accessed over the network as if it was
29896
21:29:03,784 --> 21:29:04,784
directly attached to the server
29897
21:29:06,680 --> 21:29:07,680
is because the architecture is based on
29898
21:29:09,120 --> 21:29:10,120
the client server model of scuzzy
29899
21:29:12,296 --> 21:29:13,296
it's because the parlance is referred to
29900
21:29:14,824 --> 21:29:15,824
as the initiator target model which may
29901
21:29:18,000 --> 21:29:19,000
be you may expect a question on
29902
21:29:20,336 --> 21:29:21,336
something along those lines for the exam
29903
21:29:22,760 --> 21:29:23,760
the iscosity sign consists of three
29904
21:29:25,320 --> 21:29:26,320
components
29905
21:29:27,176 --> 21:29:28,176
initiator the Target and the IP network
29906
21:29:32,760 --> 21:29:33,760
the initiators the system that first
29907
21:29:34,496 --> 21:29:35,496
initiates a read or write request over
29908
21:29:36,536 --> 21:29:37,536
the IP network
29909
21:29:38,640 --> 21:29:39,640
example of a device is the server
29910
21:29:42,360 --> 21:29:43,360
Target system is the system that
29911
21:29:44,512 --> 21:29:45,512
responds to the requests
29912
21:29:46,616 --> 21:29:47,616
so an example is the storage array
29913
21:29:50,936 --> 21:29:51,936
initiates initiators and targets need
29914
21:29:53,696 --> 21:29:54,696
the physical is because the interface to
29915
21:29:56,576 --> 21:29:57,576
connect to the IP network
29916
21:29:59,512 --> 21:30:00,512
the Isis interface is available as a PCI
29917
21:30:01,976 --> 21:30:02,976
expansion card or it can actually be
29918
21:30:03,656 --> 21:30:04,656
built into the motherboard again you
29919
21:30:06,000 --> 21:30:07,000
need to speak to the vendor and look at
29920
21:30:08,160 --> 21:30:09,160
your particular specifications and
29921
21:30:10,320 --> 21:30:11,320
requirements
29922
21:30:11,640 --> 21:30:12,640
jumbo frames you may heard of before in
29923
21:30:13,976 --> 21:30:14,976
network parlance
29924
21:30:16,016 --> 21:30:17,016
it's an Ethernet frame it's got a
29925
21:30:18,360 --> 21:30:19,360
payload greater than 1500 bytes and it
29926
21:30:21,056 --> 21:30:22,056
can carry a payload payload of up to
29927
21:30:23,040 --> 21:30:24,040
9000 bytes
29928
21:30:25,256 --> 21:30:26,256
so on the contrary an Ethernet standard
29929
21:30:28,016 --> 21:30:29,016
frame a standard ethernet frame sorry
29930
21:30:29,696 --> 21:30:30,696
can carry a payload of 1500 bytes
29931
21:30:32,936 --> 21:30:33,936
the payload or the size of the largest
29932
21:30:35,216 --> 21:30:36,216
data that an Ethernet frame can carry is
29933
21:30:37,144 --> 21:30:38,144
referred to as the MTU and if you ever
29934
21:30:40,144 --> 21:30:41,144
use a package sniffer you'll see you
29935
21:30:42,784 --> 21:30:43,784
should see for ethernet and MTU field
29936
21:30:45,120 --> 21:30:46,120
the maximum transmission unit
29937
21:30:48,176 --> 21:30:49,176
since jumbo frames have larger mtus they
29938
21:30:50,576 --> 21:30:51,576
can carry more data
29939
21:30:52,976 --> 21:30:53,976
each transmitted frame and a network
29940
21:30:54,960 --> 21:30:55,960
requires a network hardware and software
29941
21:30:57,360 --> 21:30:58,360
to process it so we have the more frames
29942
21:30:59,824 --> 21:31:00,824
we have the more CPU Cycles are required
29943
21:31:02,400 --> 21:31:03,400
to process them
29944
21:31:04,376 --> 21:31:05,376
so if we use jumbo frames it only
29945
21:31:06,960 --> 21:31:07,960
requires a few we require less frames
29946
21:31:09,720 --> 21:31:10,720
because of the bigger MTU size as a
29947
21:31:12,240 --> 21:31:13,240
result we get less CPU utilization but
29948
21:31:15,784 --> 21:31:16,784
we get the bonus of increased throughput
29949
21:31:20,040 --> 21:31:21,040
uh we can use jumbo frames when fiber
29950
21:31:22,320 --> 21:31:23,320
channel frames are to be transmitted
29951
21:31:24,240 --> 21:31:25,240
over the ethernet
29952
21:31:25,976 --> 21:31:26,976
the size of the fiber channel frames are
29953
21:31:28,256 --> 21:31:29,256
over 2K so it becomes necessary through
29954
21:31:30,784 --> 21:31:31,784
the adapters and switches to support
29955
21:31:33,424 --> 21:31:34,424
baby jumbo frames in order to prevent
29956
21:31:36,296 --> 21:31:37,296
the segmentation I think we covered
29957
21:31:38,464 --> 21:31:39,464
segmentation early it's when the frame
29958
21:31:40,376 --> 21:31:41,376
is chopped up into different pieces
29959
21:31:42,600 --> 21:31:43,600
numbered and then transmitted and each
29960
21:31:45,600 --> 21:31:46,600
frame has to
29961
21:31:47,336 --> 21:31:48,336
um has to have an acknowledgments so
29962
21:31:49,256 --> 21:31:50,256
you've got a lot of overhead associated
29963
21:31:53,040 --> 21:31:54,040
all right so we've looked in brief at
29964
21:31:54,896 --> 21:31:55,896
storage area networks direct attached
29965
21:31:57,056 --> 21:31:58,056
storage Nas
29966
21:31:58,976 --> 21:31:59,976
uh Sun versus Das Sun media
29967
21:32:02,936 --> 21:32:03,936
fiber channel and iscs architecture and
29968
21:32:06,176 --> 21:32:07,176
Sam
29969
21:32:07,016 --> 21:32:08,016
the components of Isco Z and jumbo
29970
21:32:09,960 --> 21:32:10,960
frames
29971
21:32:11,040 --> 21:32:12,040
thanks for watching
29972
21:32:15,470 --> 21:32:16,470
[Music]
29973
21:32:31,320 --> 21:32:32,320
welcome to module 17 lesson 4 Cloud
29974
21:32:33,896 --> 21:32:34,896
Concepts I've mentioned earlier well
29975
21:32:36,480 --> 21:32:37,480
worth doing the CompTIA Cloud Essentials
29976
21:32:39,056 --> 21:32:40,056
exam because uh cloud computing is just
29977
21:32:42,832 --> 21:32:43,832
one of the core subjects that you need
29978
21:32:45,424 --> 21:32:46,424
to understand as a network engineer
29979
21:32:47,480 --> 21:32:48,480
among us a few others including routing
29980
21:32:50,400 --> 21:32:51,400
virtualization
29981
21:32:53,400 --> 21:32:54,400
um
29982
21:32:54,296 --> 21:32:55,296
probably Amazon storage
29983
21:32:56,720 --> 21:32:57,720
uh routing and switching for example the
29984
21:32:59,872 --> 21:33:00,872
CCNA IPv6
29985
21:33:03,784 --> 21:33:04,784
so this is just a real uh brief taster
29986
21:33:07,504 --> 21:33:08,504
looking at cloud computing
29987
21:33:08,936 --> 21:33:09,936
characteristics on-demand self-service
29988
21:33:11,824 --> 21:33:12,824
broad network access resource pooling
29989
21:33:15,240 --> 21:33:16,240
elasticity measured service software as
29990
21:33:19,080 --> 21:33:20,080
a service platform as a service
29991
21:33:21,552 --> 21:33:22,552
infrastructure as a service
29992
21:33:24,000 --> 21:33:25,000
and then private community and public
29993
21:33:26,640 --> 21:33:27,640
clouds on hybrid clouds
29994
21:33:30,240 --> 21:33:31,240
so best thing is to start with the
29995
21:33:32,280 --> 21:33:33,280
definition so we can kind of have an
29996
21:33:34,800 --> 21:33:35,800
agreed kicking off point of what cloud
29997
21:33:36,656 --> 21:33:37,656
computing actually is
29998
21:33:39,800 --> 21:33:40,800
now cloud computing from the definition
29999
21:33:42,600 --> 21:33:43,600
is a model for enabling ubiquitous
30000
21:33:45,552 --> 21:33:46,552
convenient on-demand network access to a
30001
21:33:48,424 --> 21:33:49,424
shared pool of configurable computing
30002
21:33:50,936 --> 21:33:51,936
resources examples are network servers
30003
21:33:54,000 --> 21:33:55,000
storage application and services that
30004
21:33:57,240 --> 21:33:58,240
can be rapidly provisioned and released
30005
21:33:58,856 --> 21:33:59,856
with minimal management effort or
30006
21:34:01,256 --> 21:34:02,256
service provider interaction we've all
30007
21:34:03,896 --> 21:34:04,896
used the cloud already if you've used
30008
21:34:05,576 --> 21:34:06,576
any storage for example Dropbox
30009
21:34:08,960 --> 21:34:09,960
box.com I think the call for storage any
30010
21:34:12,240 --> 21:34:13,240
Google services for example Gmail or
30011
21:34:14,760 --> 21:34:15,760
Google documents and things like that
30012
21:34:17,936 --> 21:34:18,936
there's many many others
30013
21:34:19,760 --> 21:34:20,760
and are all based on the cloud
30014
21:34:24,296 --> 21:34:25,296
so some characteristics that you need to
30015
21:34:27,424 --> 21:34:28,424
remember these so make sure you note
30016
21:34:28,976 --> 21:34:29,976
them down there's five characteristics
30017
21:34:31,616 --> 21:34:32,616
of cloud computing on demand
30018
21:34:33,960 --> 21:34:34,960
self-service broader network access
30019
21:34:36,832 --> 21:34:37,832
we'll go into all of these in more
30020
21:34:38,640 --> 21:34:39,640
detail resource pooling rapid elastis
30021
21:34:42,424 --> 21:34:43,424
elasticity
30022
21:34:44,696 --> 21:34:45,696
a measured service
30023
21:34:46,976 --> 21:34:47,976
so on demand basically means the user
30024
21:34:49,256 --> 21:34:50,256
can provision resources as and when
30025
21:34:51,896 --> 21:34:52,896
they're needed without getting any human
30026
21:34:53,640 --> 21:34:54,640
assistance so you if you needed more
30027
21:34:56,512 --> 21:34:57,512
memory you wouldn't have to log a ticket
30028
21:34:58,256 --> 21:34:59,256
and you wouldn't have to have an
30029
21:34:59,936 --> 21:35:00,936
engineer somewhere
30030
21:35:01,440 --> 21:35:02,440
turn off the server or whatever the
30031
21:35:03,832 --> 21:35:04,832
device is adds more physical memory
30032
21:35:05,960 --> 21:35:06,960
reboot it and then answer the ticket as
30033
21:35:08,824 --> 21:35:09,824
you may well have had to do in the not
30034
21:35:10,376 --> 21:35:11,376
too distance past you click a button and
30035
21:35:13,144 --> 21:35:14,144
more is available
30036
21:35:15,056 --> 21:35:16,056
we can do when consumers provision the
30037
21:35:17,696 --> 21:35:18,696
resources based on their needs those
30038
21:35:19,744 --> 21:35:20,744
resources are automatically allocated
30039
21:35:22,192 --> 21:35:23,192
from a shared pool
30040
21:35:24,360 --> 21:35:25,360
and their schedules provided by the
30041
21:35:26,400 --> 21:35:27,400
cloud service provider
30042
21:35:28,320 --> 21:35:29,320
broad network access means that when the
30043
21:35:31,440 --> 21:35:32,440
consumers have provisioned the resources
30044
21:35:34,144 --> 21:35:35,144
they can access these from a number of
30045
21:35:36,656 --> 21:35:37,656
devices workstations laptops tablets and
30046
21:35:39,176 --> 21:35:40,176
mobile devices and mobile phones
30047
21:35:42,600 --> 21:35:43,600
resource pooling and the service
30048
21:35:44,936 --> 21:35:45,936
providers resources are shared and when
30049
21:35:48,000 --> 21:35:49,000
the consumers on a multi-tenant Model
30050
21:35:50,336 --> 21:35:51,336
where consumers get a dynamic allocation
30051
21:35:52,856 --> 21:35:53,856
resources based upon their needs
30052
21:35:55,800 --> 21:35:56,800
so sometimes consumers may need more
30053
21:35:58,552 --> 21:35:59,552
Computer Resources and other times they
30054
21:36:01,376 --> 21:36:02,376
need need less so it has to adapt for
30055
21:36:04,320 --> 21:36:05,320
this particular requirement it's
30056
21:36:06,960 --> 21:36:07,960
um
30057
21:36:07,744 --> 21:36:08,744
resource allocation based upon demand
30058
21:36:12,240 --> 21:36:13,240
rapid elasticity I can't say that word
30059
21:36:14,872 --> 21:36:15,872
elasticity
30060
21:36:16,320 --> 21:36:17,320
foreign
30061
21:36:17,216 --> 21:36:18,216
now a consumer can be allocated more res
30062
21:36:19,856 --> 21:36:20,856
me more more resources if needed at the
30063
21:36:23,336 --> 21:36:24,336
same time if for any reason they need
30064
21:36:25,080 --> 21:36:26,080
less because the more you the more you
30065
21:36:27,000 --> 21:36:28,000
need the more you pay obviously if you
30066
21:36:29,280 --> 21:36:30,280
need less then they can be downsized to
30067
21:36:31,616 --> 21:36:32,616
provide whatever model you need the
30068
21:36:34,856 --> 21:36:35,856
resources you need
30069
21:36:36,600 --> 21:36:37,600
so it appears to the consumer that there
30070
21:36:39,000 --> 21:36:40,000
there's an actual unlimited amount of
30071
21:36:41,400 --> 21:36:42,400
resources for them at any given time
30072
21:36:45,440 --> 21:36:46,440
elasticity provides a lot of savings
30073
21:36:47,512 --> 21:36:48,512
because it's not possible when you have
30074
21:36:49,856 --> 21:36:50,856
a traditional data center that you've
30075
21:36:51,784 --> 21:36:52,784
built and you own you can't grow it and
30076
21:36:54,240 --> 21:36:55,240
shrink it as and when needed
30077
21:36:57,424 --> 21:36:58,424
obviously is measured just like a meter
30078
21:37:00,240 --> 21:37:01,240
so you're charged based upon your
30079
21:37:02,872 --> 21:37:03,872
um a number of things such as
30080
21:37:04,856 --> 21:37:05,856
um memory you need uh storage and uh
30081
21:37:09,000 --> 21:37:10,000
bandwidth
30082
21:37:13,376 --> 21:37:14,376
so you get what you pay for which you've
30083
21:37:14,936 --> 21:37:15,936
already said is um uh tracked normally
30084
21:37:18,536 --> 21:37:19,536
you can log in and you can track your
30085
21:37:20,824 --> 21:37:21,824
use of resources in real time as well as
30086
21:37:23,696 --> 21:37:24,696
historical data looking at
30087
21:37:26,400 --> 21:37:27,400
um how much you've used and the
30088
21:37:28,144 --> 21:37:29,144
projected requirements based on previous
30089
21:37:31,080 --> 21:37:32,080
usage and you can see how much you're
30090
21:37:33,480 --> 21:37:34,480
going to have to pay how much you paid
30091
21:37:35,760 --> 21:37:36,760
in the past
30092
21:37:37,192 --> 21:37:38,192
there's three service models you need to
30093
21:37:39,120 --> 21:37:40,120
be familiar with software as a service
30094
21:37:41,424 --> 21:37:42,424
platform as a service infrastructure as
30095
21:37:44,464 --> 21:37:45,464
a service
30096
21:37:46,160 --> 21:37:47,160
providers provide the services to
30097
21:37:48,536 --> 21:37:49,536
Consumers based on these three service
30098
21:37:51,240 --> 21:37:52,240
models so SAS swas or SAS
30099
21:37:57,120 --> 21:37:58,120
consumers can use the service provider
30100
21:37:59,216 --> 21:38:00,216
software applications and databases over
30101
21:38:01,376 --> 21:38:02,376
a network without the need to install
30102
21:38:03,360 --> 21:38:04,360
any software except for a web browser
30103
21:38:06,720 --> 21:38:07,720
you need to access
30104
21:38:08,536 --> 21:38:09,536
these uh software applications databases
30105
21:38:11,336 --> 21:38:12,336
run on the cloud so imagine you're
30106
21:38:13,080 --> 21:38:14,080
trying to program
30107
21:38:15,296 --> 21:38:16,296
um some application for example or just
30108
21:38:18,240 --> 21:38:19,240
use a huge amount of resources or
30109
21:38:19,856 --> 21:38:20,856
develop a program you can use the
30110
21:38:21,832 --> 21:38:22,832
provider's resources and scale it as and
30111
21:38:23,872 --> 21:38:24,872
when needed
30112
21:38:25,144 --> 21:38:26,144
it's provided as a shared Computing
30113
21:38:27,424 --> 21:38:28,424
resource to the consumers
30114
21:38:29,640 --> 21:38:30,640
it's essentially the aggregation of
30115
21:38:31,376 --> 21:38:32,376
hardware and software
30116
21:38:33,000 --> 21:38:34,000
used to support the cloud services a few
30117
21:38:36,240 --> 21:38:37,240
examples you can see there are Twitter
30118
21:38:37,856 --> 21:38:38,856
and Facebook there's a whole bunch of
30119
21:38:39,360 --> 21:38:40,360
others you can look into if you wish
30120
21:38:41,464 --> 21:38:42,464
though in the SAS model consumers access
30121
21:38:45,296 --> 21:38:46,296
the shared applications over a network
30122
21:38:47,040 --> 21:38:48,040
from various client devices
30123
21:38:50,400 --> 21:38:51,400
it doesn't give you the ability to
30124
21:38:52,192 --> 21:38:53,192
control and manage in the manage the
30125
21:38:53,936 --> 21:38:54,936
underlying Cloud infrastructure so you
30126
21:38:56,640 --> 21:38:57,640
can't manage the operating system
30127
21:38:57,896 --> 21:38:58,896
servers the network or storage and you
30128
21:39:01,856 --> 21:39:02,856
don't you don't want to anywhere you
30129
21:39:03,240 --> 21:39:04,240
just want to um use it as is
30130
21:39:08,104 --> 21:39:09,104
platform as a service there's an example
30131
21:39:10,080 --> 21:39:11,080
there Windows Azure which you could look
30132
21:39:11,872 --> 21:39:12,872
into in your own time in the platform as
30133
21:39:14,640 --> 21:39:15,640
a service model consumers have the
30134
21:39:16,616 --> 21:39:17,616
ability to develop and deploy software
30135
21:39:18,424 --> 21:39:19,424
applications on the service providers
30136
21:39:20,872 --> 21:39:21,872
Cloud infrastructure
30137
21:39:23,040 --> 21:39:24,040
uh the service provider typically
30138
21:39:24,832 --> 21:39:25,832
provides a competing platform comprised
30139
21:39:27,480 --> 21:39:28,480
of the operating system and the
30140
21:39:29,280 --> 21:39:30,280
application development environment
30141
21:39:31,744 --> 21:39:32,744
this includes programming languages
30142
21:39:33,424 --> 21:39:34,424
libraries tools databases and web
30143
21:39:35,464 --> 21:39:36,464
servers I recommend you look at the
30144
21:39:37,504 --> 21:39:38,504
Amazon
30145
21:39:38,424 --> 21:39:39,424
AWS qualifications for more information
30146
21:39:41,040 --> 21:39:42,040
on these
30147
21:39:42,536 --> 21:39:43,536
in the paas model
30148
21:39:45,480 --> 21:39:46,480
consumers can develop and deploy
30149
21:39:47,280 --> 21:39:48,280
software without the need to maintain
30150
21:39:48,656 --> 21:39:49,656
the operating system so you can imagine
30151
21:39:50,160 --> 21:39:51,160
how convenient this is to fire up an
30152
21:39:52,744 --> 21:39:53,744
instance for example if you logged into
30153
21:39:54,424 --> 21:39:55,424
the Amazon or the Google cloud and start
30154
21:39:57,424 --> 21:39:58,424
doing your developing it's just so easy
30155
21:39:59,824 --> 21:40:00,824
and quick
30156
21:40:01,144 --> 21:40:02,144
consumers have control over the deployed
30157
21:40:04,256 --> 21:40:05,256
software application and the
30158
21:40:05,936 --> 21:40:06,936
configuration settings
30159
21:40:08,160 --> 21:40:09,160
and it doesn't give you to again
30160
21:40:11,120 --> 21:40:12,120
manage the controller manager underlying
30161
21:40:14,280 --> 21:40:15,280
infrastructure
30162
21:40:17,040 --> 21:40:18,040
infrastructure as a service one example
30163
21:40:19,320 --> 21:40:20,320
is Amazon ec2 web services
30164
21:40:23,936 --> 21:40:24,936
here consumers access a dedicated
30165
21:40:26,336 --> 21:40:27,336
physical or in most cases a virtual
30166
21:40:28,976 --> 21:40:29,976
machine running on the service providers
30167
21:40:31,376 --> 21:40:32,376
Cloud infrastructure
30168
21:40:33,832 --> 21:40:34,832
a lot of people use this for web hosting
30169
21:40:37,744 --> 21:40:38,744
especially WordPress is quite easy to
30170
21:40:39,600 --> 21:40:40,600
fire up an instance and get it all
30171
21:40:40,976 --> 21:40:41,976
working
30172
21:40:42,000 --> 21:40:43,000
virtual machine typically comes with a
30173
21:40:43,920 --> 21:40:44,920
server operating system consumers
30174
21:40:46,256 --> 21:40:47,256
complete complete control over the OS
30175
21:40:48,424 --> 21:40:49,424
and can control the updates
30176
21:40:53,216 --> 21:40:54,216
um you have control over the operating
30177
21:40:55,376 --> 21:40:56,376
system application storage you have
30178
21:40:57,960 --> 21:40:58,960
limited control over the selected
30179
21:40:59,784 --> 21:41:00,784
networking components such as the
30180
21:41:02,280 --> 21:41:03,280
firewall that's protecting your
30181
21:41:03,720 --> 21:41:04,720
particular virtual device
30182
21:41:06,424 --> 21:41:07,424
again you can't control the underlying
30183
21:41:08,640 --> 21:41:09,640
Cloud infrastructure probably
30184
21:41:10,976 --> 21:41:11,976
um neither would you want to
30185
21:41:13,920 --> 21:41:14,920
infrastructure as a service you've got
30186
21:41:15,720 --> 21:41:16,720
four models to choose from for iaas
30187
21:41:20,872 --> 21:41:21,872
you've got the private Cloud the
30188
21:41:22,376 --> 21:41:23,376
community Cloud public and hybrid
30189
21:41:25,504 --> 21:41:26,504
for private Cloud the cloud
30190
21:41:27,424 --> 21:41:28,424
infrastructure is provisioned
30191
21:41:28,800 --> 21:41:29,800
exclusively for a single organization
30192
21:41:31,680 --> 21:41:32,680
so you get exclusive use of this you've
30193
21:41:34,192 --> 21:41:35,192
probably hired a company
30194
21:41:35,760 --> 21:41:36,760
to create all of the infrastructure for
30195
21:41:37,920 --> 21:41:38,920
you and nobody else can have access to
30196
21:41:40,376 --> 21:41:41,376
it and all of your offices and remote
30197
21:41:43,256 --> 21:41:44,256
offices will have access
30198
21:41:46,256 --> 21:41:47,256
owned operated and managed by the
30199
21:41:48,296 --> 21:41:49,296
organization itself
30200
21:41:50,104 --> 21:41:51,104
very third party or a combination
30201
21:41:53,576 --> 21:41:54,576
a physical location could be within your
30202
21:41:55,680 --> 21:41:56,680
premises or it could be located
30203
21:41:57,056 --> 21:41:58,056
Elsewhere on the cloud
30204
21:41:59,512 --> 21:42:00,512
Community it's um Provisions for a
30205
21:42:02,872 --> 21:42:03,872
specific community of consumers from
30206
21:42:05,216 --> 21:42:06,216
organizations that share common concerns
30207
21:42:07,616 --> 21:42:08,616
such as security compliance
30208
21:42:09,720 --> 21:42:10,720
jurisdiction and so on for example would
30209
21:42:12,176 --> 21:42:13,176
be law reinforcement
30210
21:42:14,104 --> 21:42:15,104
in this model the cloud infrastructure
30211
21:42:15,832 --> 21:42:16,832
may be owned operated by one or more
30212
21:42:17,640 --> 21:42:18,640
organizations by a third party or you
30213
21:42:20,576 --> 21:42:21,576
could have a combination
30214
21:42:22,744 --> 21:42:23,744
the physical location and may be within
30215
21:42:25,376 --> 21:42:26,376
your premises or it could be located
30216
21:42:27,240 --> 21:42:28,240
elsewhere
30217
21:42:29,104 --> 21:42:30,104
in public Cloud it's provision for the
30218
21:42:31,192 --> 21:42:32,192
general public so it can be used by the
30219
21:42:33,480 --> 21:42:34,480
general public over a network such as
30220
21:42:36,056 --> 21:42:37,056
the internet
30221
21:42:38,872 --> 21:42:39,872
um the cloud infrastructure could be
30222
21:42:40,800 --> 21:42:41,800
managed by the government businesses
30223
21:42:42,480 --> 21:42:43,480
Academia or a combination
30224
21:42:46,192 --> 21:42:47,192
foreign physical location is within the
30225
21:42:49,552 --> 21:42:50,552
premise of the service provider now a
30226
21:42:51,896 --> 21:42:52,896
hybrid is a mixture of any of these
30227
21:42:56,040 --> 21:42:57,040
separate entities but are integrated
30228
21:42:57,960 --> 21:42:58,960
into the benefits for the um of the
30229
21:43:00,056 --> 21:43:01,056
multiple deployed models
30230
21:43:02,640 --> 21:43:03,640
example is when the it organization uses
30231
21:43:05,216 --> 21:43:06,216
a public card as a temporary solution to
30232
21:43:07,976 --> 21:43:08,976
meet um an excess capacity demand that
30233
21:43:10,744 --> 21:43:11,744
can't be met by their private setup
30234
21:43:15,120 --> 21:43:16,120
so I've looked at quite a few things
30235
21:43:16,616 --> 21:43:17,616
here you need to make some notes
30236
21:43:18,480 --> 21:43:19,480
obviously because there's a few things
30237
21:43:19,744 --> 21:43:20,744
to remember for the exam
30238
21:43:23,040 --> 21:43:24,040
service models software as a service
30239
21:43:26,336 --> 21:43:27,336
platform infrastructure private
30240
21:43:29,216 --> 21:43:30,216
community and public cloud and hybrid
30241
21:43:32,216 --> 21:43:33,216
okay that's all for now thanks for
30242
21:43:33,832 --> 21:43:34,832
watching
30243
21:43:37,570 --> 21:43:38,570
[Music]
30244
21:43:53,696 --> 21:43:54,696
welcome to module 18 lesson one physical
30245
21:43:56,104 --> 21:43:57,104
security controls I'm going to whisk
30246
21:43:58,856 --> 21:43:59,856
through this pretty quickly because most
30247
21:44:00,176 --> 21:44:01,176
of it is pretty self-explanatory
30248
21:44:03,320 --> 21:44:04,320
and Common Sense really physical
30249
21:44:06,720 --> 21:44:07,720
security man traps Network closets video
30250
21:44:10,496 --> 21:44:11,496
monitoring door access controls
30251
21:44:12,856 --> 21:44:13,856
proximity readers biometrics
30252
21:44:15,896 --> 21:44:16,896
Cipher locks and a security guard
30253
21:44:20,400 --> 21:44:21,400
so the physical security control is the
30254
21:44:23,040 --> 21:44:24,040
measures we take from physical threats
30255
21:44:25,552 --> 21:44:26,552
basically people trying to get into our
30256
21:44:28,744 --> 21:44:29,744
data center
30257
21:44:30,600 --> 21:44:31,600
I guess Ram radio might be included
30258
21:44:32,640 --> 21:44:33,640
because I've never heard of that but uh
30259
21:44:34,744 --> 21:44:35,744
yeah physical security
30260
21:44:38,176 --> 21:44:39,176
examples I've already mentioned the man
30261
21:44:40,744 --> 21:44:41,744
traps the network closets
30262
21:44:43,080 --> 21:44:44,080
they reduce the risk of damage or loss
30263
21:44:45,424 --> 21:44:46,424
by preventing or slowing down physical
30264
21:44:47,040 --> 21:44:48,040
attack I've actually been a worked uh or
30265
21:44:50,512 --> 21:44:51,512
been to a few networks Consulting where
30266
21:44:53,872 --> 21:44:54,872
they don't have any security whatsoever
30267
21:44:57,192 --> 21:44:58,192
everything's shoved in a Cupboard and
30268
21:44:59,336 --> 21:45:00,336
the entire company website the
30269
21:45:01,856 --> 21:45:02,856
financials the accounting all stuck on
30270
21:45:05,160 --> 21:45:06,160
the server hanging off a cable in a
30271
21:45:06,784 --> 21:45:07,784
Cupboard and I'm sure you've seen the
30272
21:45:08,872 --> 21:45:09,872
pictures or may have seen it yourself
30273
21:45:10,192 --> 21:45:11,192
for real
30274
21:45:11,464 --> 21:45:12,464
and it's pretty easy to do it doesn't
30275
21:45:13,256 --> 21:45:14,256
have to be expensive a man trap I've
30276
21:45:15,896 --> 21:45:16,896
experienced in a internet service
30277
21:45:18,896 --> 21:45:19,896
provider that used to host some of my
30278
21:45:20,872 --> 21:45:21,872
equipment
30279
21:45:22,496 --> 21:45:23,496
basically it's a space it's a door
30280
21:45:26,040 --> 21:45:27,040
um within a door so you go through one
30281
21:45:28,376 --> 21:45:29,376
set of doors which it normally has got
30282
21:45:29,936 --> 21:45:30,936
some type of security keypads or
30283
21:45:32,336 --> 21:45:33,336
whatever and then you've got a second
30284
21:45:33,960 --> 21:45:34,960
set of doors you have to go through if
30285
21:45:36,360 --> 21:45:37,360
it's a manual Man Trap or security guard
30286
21:45:38,160 --> 21:45:39,160
locks and unlocks each doors and
30287
21:45:39,720 --> 21:45:40,720
sequence if it's automatic the doors are
30288
21:45:42,360 --> 21:45:43,360
only opened after getting an
30289
21:45:43,856 --> 21:45:44,856
identification from the person
30290
21:45:46,496 --> 21:45:47,496
uh the one I went to you had to do a
30291
21:45:48,480 --> 21:45:49,480
keypad to get through the front door and
30292
21:45:50,464 --> 21:45:51,464
then actually pick up a phone and speak
30293
21:45:52,016 --> 21:45:53,016
to the on-call engineer to get through
30294
21:45:55,080 --> 21:45:56,080
the second door
30295
21:45:56,512 --> 21:45:57,512
and it all had to be done by appointment
30296
21:45:59,400 --> 21:46:00,400
our Network closet is is a room where
30297
21:46:01,616 --> 21:46:02,616
Network hardware switches switches and
30298
21:46:03,600 --> 21:46:04,600
routers are installed physical access to
30299
21:46:06,056 --> 21:46:07,056
the closet is normally restricted by
30300
21:46:07,800 --> 21:46:08,800
having some sort of security control
30301
21:46:10,744 --> 21:46:11,744
videos
30302
21:46:12,720 --> 21:46:13,720
um normally record who comes in who goes
30303
21:46:15,656 --> 21:46:16,656
out who accesses what and where and it's
30304
21:46:18,240 --> 21:46:19,240
recorded for a set period of time this
30305
21:46:21,296 --> 21:46:22,296
can be CCTV or video over IP
30306
21:46:25,376 --> 21:46:26,376
foreign
30307
21:46:27,856 --> 21:46:28,856
electronic system I'm sure you've used
30308
21:46:30,296 --> 21:46:31,296
these in a lot of different places to
30309
21:46:31,800 --> 21:46:32,800
get in and out of different rooms and
30310
21:46:33,960 --> 21:46:34,960
buildings and floors and use a granted
30311
21:46:37,744 --> 21:46:38,744
access door if the door is open for a
30312
21:46:39,600 --> 21:46:40,600
predetermined amount of time and the
30313
21:46:41,760 --> 21:46:42,760
entry is recorded the door remains
30314
21:46:44,280 --> 21:46:45,280
closed when the users denied access that
30315
21:46:46,552 --> 21:46:47,552
attempt is still recorded
30316
21:46:48,656 --> 21:46:49,656
if the doors held open for too long then
30317
21:46:51,536 --> 21:46:52,536
it should trigger some sort of action or
30318
21:46:53,824 --> 21:46:54,824
alarm
30319
21:46:54,960 --> 21:46:55,960
proximity reader is basically electronic
30320
21:46:58,680 --> 21:46:59,680
access where you have some sort of smart
30321
21:47:00,536 --> 21:47:01,536
card and you swipe your way in and
30322
21:47:03,720 --> 21:47:04,720
possibly out again as well you'll
30323
21:47:05,936 --> 21:47:06,936
normally hold the card on or in the
30324
21:47:08,512 --> 21:47:09,512
reader
30325
21:47:09,720 --> 21:47:10,720
proximity read normally bleeps or beeps
30326
21:47:12,360 --> 21:47:13,360
when it has red your smart card if it
30327
21:47:15,176 --> 21:47:16,176
doesn't read it you may hear a different
30328
21:47:16,680 --> 21:47:17,680
type of beep and you may have to go and
30329
21:47:19,616 --> 21:47:20,616
get your car checked or renewed
30330
21:47:22,376 --> 21:47:23,376
when the user's granted access to the
30331
21:47:23,936 --> 21:47:24,936
door will open otherwise it remains
30332
21:47:25,800 --> 21:47:26,800
closed
30333
21:47:27,240 --> 21:47:28,240
it's pretty obvious to be honest
30334
21:47:29,576 --> 21:47:30,576
Biometrics refers to remetrics related
30335
21:47:32,336 --> 21:47:33,336
to human characteristics fingerprint
30336
21:47:35,040 --> 21:47:36,040
face Iris retina and so on and so forth
30337
21:47:38,280 --> 21:47:39,280
if you've seen it if you've watched any
30338
21:47:40,144 --> 21:47:41,144
of the um Mission Impossible movies
30339
21:47:44,400 --> 21:47:45,400
uh since Biometrics are unique to
30340
21:47:46,320 --> 21:47:47,320
individuals they're used to verify the
30341
21:47:47,760 --> 21:47:48,760
identity of an individual before
30342
21:47:49,192 --> 21:47:50,192
granting access the biometric locks
30343
21:47:52,256 --> 21:47:53,256
Grant access only if the biometric
30344
21:47:54,656 --> 21:47:55,656
feature is validated for example
30345
21:47:57,656 --> 21:47:58,656
scanning your fingerprint
30346
21:48:01,256 --> 21:48:02,256
keypad and Cipher locks the cipher lock
30347
21:48:04,144 --> 21:48:05,144
uses a keypad in place of a keyhole
30348
21:48:07,192 --> 21:48:08,192
use us to provide the correct numerical
30349
21:48:10,016 --> 21:48:11,016
pin code by pressing buttons on the
30350
21:48:12,480 --> 21:48:13,480
keypad cypherlock could have four or
30351
21:48:15,296 --> 21:48:16,296
five push button combination in order to
30352
21:48:17,512 --> 21:48:18,512
get in
30353
21:48:19,216 --> 21:48:20,216
uh Cipher code is created at the initial
30354
21:48:22,376 --> 21:48:23,376
setup but obviously can be changed
30355
21:48:23,824 --> 21:48:24,824
usually changed every week or every
30356
21:48:25,504 --> 21:48:26,504
month
30357
21:48:26,824 --> 21:48:27,824
and the security guard is the whoever's
30358
21:48:29,760 --> 21:48:30,760
been
30359
21:48:30,720 --> 21:48:31,720
uh got on the course got qualified and
30360
21:48:34,320 --> 21:48:35,320
um it has become the security person it
30361
21:48:37,616 --> 21:48:38,616
has a legal or inappropriate actions
30362
21:48:40,616 --> 21:48:41,616
all right so covered some
30363
21:48:43,144 --> 21:48:44,144
following items all fairly obvious I
30364
21:48:45,656 --> 21:48:46,656
think just to make a few notes for the
30365
21:48:48,832 --> 21:48:49,832
exam and I'll see you on the next
30366
21:48:50,760 --> 21:48:51,760
presentation thanks for watching
30367
21:48:58,430 --> 21:48:59,430
[Music]
30368
21:49:08,424 --> 21:49:09,424
welcome to module 18 lesson 2 basic
30369
21:49:12,056 --> 21:49:13,056
forensic Concepts
30370
21:49:14,400 --> 21:49:15,400
this is one of the new additions to the
30371
21:49:16,800 --> 21:49:17,800
network plus syllabus and it's basically
30372
21:49:19,976 --> 21:49:20,976
because of the increased scope for
30373
21:49:21,536 --> 21:49:22,536
Network engineers
30374
21:49:23,104 --> 21:49:24,104
and the more formal proceedings we have
30375
21:49:26,576 --> 21:49:27,576
in um respective Cube and computer
30376
21:49:29,824 --> 21:49:30,824
forensics
30377
21:49:31,504 --> 21:49:32,504
so this is quite um
30378
21:49:33,424 --> 21:49:34,424
an emerging field of
30379
21:49:36,120 --> 21:49:37,120
um law
30380
21:49:37,744 --> 21:49:38,744
and evidence and obviously we've got uh
30381
21:49:41,104 --> 21:49:42,104
forensic investigations going on now in
30382
21:49:44,512 --> 21:49:45,512
terms of um terrorism and other
30383
21:49:47,464 --> 21:49:48,464
threats and crimes and um we need to be
30384
21:49:50,760 --> 21:49:51,760
familiar with some of the basics
30385
21:49:52,856 --> 21:49:53,856
so what are forensics and computer
30386
21:49:54,784 --> 21:49:55,784
forensics the First Responders job
30387
21:49:58,216 --> 21:49:59,216
electronic discovery
30388
21:50:01,080 --> 21:50:02,080
chain of custody
30389
21:50:03,360 --> 21:50:04,360
legal holds securing the crime scene
30390
21:50:07,256 --> 21:50:08,256
high level View
30391
21:50:09,784 --> 21:50:10,784
some steps in basic forensic process
30392
21:50:12,424 --> 21:50:13,424
including collection examination
30393
21:50:14,720 --> 21:50:15,720
analysis and Reporting
30394
21:50:17,400 --> 21:50:18,400
so what is forensics or what are
30395
21:50:19,440 --> 21:50:20,440
forensics is the scientific methods and
30396
21:50:22,744 --> 21:50:23,744
techniques for collecting analyzing and
30397
21:50:25,552 --> 21:50:26,552
preserving evidence that's the
30398
21:50:27,296 --> 21:50:28,296
definition
30399
21:50:29,872 --> 21:50:30,872
can be used in the court of law and if
30400
21:50:31,976 --> 21:50:32,976
anything's going to be used in a quarter
30401
21:50:33,360 --> 21:50:34,360
law it normally has to follow a certain
30402
21:50:35,640 --> 21:50:36,640
amount of um procedures in order to
30403
21:50:38,400 --> 21:50:39,400
qualify as evidence as we'll see
30404
21:50:41,512 --> 21:50:42,512
the um computer forensics U.S government
30405
21:50:45,120 --> 21:50:46,120
organization states are following
30406
21:50:48,000 --> 21:50:49,000
computer forensics is defined as the
30407
21:50:50,216 --> 21:50:51,216
discipline that combines elements of law
30408
21:50:52,016 --> 21:50:53,016
on computer science to collect and
30409
21:50:54,120 --> 21:50:55,120
analyze data from computer systems
30410
21:50:56,160 --> 21:50:57,160
networks Wireless comms and storage
30411
21:50:58,800 --> 21:50:59,800
devices in a way that's admissible as
30412
21:51:01,016 --> 21:51:02,016
evidence in accord to law
30413
21:51:02,872 --> 21:51:03,872
and it all hinges on that last sentence
30414
21:51:04,856 --> 21:51:05,856
really it has to be admissible and we'll
30415
21:51:07,440 --> 21:51:08,440
go into the chain custody in a bit this
30416
21:51:10,320 --> 21:51:11,320
uh when I worked in the police it
30417
21:51:11,760 --> 21:51:12,760
applied to physical evidence in as much
30418
21:51:14,280 --> 21:51:15,280
as we had to know
30419
21:51:15,960 --> 21:51:16,960
who first sees the evidence who do they
30420
21:51:18,720 --> 21:51:19,720
hand it to who examined it after that
30421
21:51:21,296 --> 21:51:22,296
and so on and we have to have this
30422
21:51:23,336 --> 21:51:24,336
continuity
30423
21:51:24,720 --> 21:51:25,720
and it's the same in regards of computer
30424
21:51:26,936 --> 21:51:27,936
forensics
30425
21:51:30,176 --> 21:51:31,176
computer forensics help organizations
30426
21:51:32,280 --> 21:51:33,280
deal with security incidents that have
30427
21:51:34,320 --> 21:51:35,320
an adverse impact on their business so
30428
21:51:36,896 --> 21:51:37,896
it could be for internal investigations
30429
21:51:38,696 --> 21:51:39,696
also
30430
21:51:40,144 --> 21:51:41,144
security incidents are events that
30431
21:51:42,360 --> 21:51:43,360
violate the security policies of the
30432
21:51:44,216 --> 21:51:45,216
organization so obviously some things
30433
21:51:46,256 --> 21:51:47,256
may not be a crime however sharing
30434
21:51:48,960 --> 21:51:49,960
sensitive information as regards of your
30435
21:51:51,832 --> 21:51:52,832
company or take over bids or other
30436
21:51:54,832 --> 21:51:55,832
information about people at work there
30437
21:51:56,936 --> 21:51:57,936
can be a breach even though it hasn't um
30438
21:51:59,872 --> 21:52:00,872
it isn't officially a crime for whatever
30439
21:52:02,040 --> 21:52:03,040
reason
30440
21:52:03,424 --> 21:52:04,424
here's a screen grab if you search for
30441
21:52:06,720 --> 21:52:07,720
um computer forensic certifications the
30442
21:52:09,960 --> 21:52:10,960
website Tom's it pro has listed what uh
30443
21:52:14,104 --> 21:52:15,104
for 2017 are the top five
30444
21:52:17,512 --> 21:52:18,512
uh computer forensic qualifications the
30445
21:52:21,000 --> 21:52:22,000
certified computer examiner in case
30446
21:52:23,336 --> 21:52:24,336
which is a um vendor specific the other
30447
21:52:27,056 --> 21:52:28,056
ones are vendor neutral I think
30448
21:52:28,856 --> 21:52:29,856
certified forensic computer examiner
30449
21:52:32,336 --> 21:52:33,336
um
30450
21:52:33,616 --> 21:52:34,616
gcfa and gcfe
30451
21:52:37,016 --> 21:52:38,016
I'm not sure that stands for cyber
30452
21:52:38,936 --> 21:52:39,936
security forensics so um if you're
30453
21:52:41,464 --> 21:52:42,464
interested in this particular field then
30454
21:52:43,680 --> 21:52:44,680
there's certainly other certifications
30455
21:52:45,120 --> 21:52:46,120
you can follow
30456
21:52:46,976 --> 21:52:47,976
uh just do some research and see what uh
30457
21:52:50,160 --> 21:52:51,160
the employment prospects are
30458
21:52:52,680 --> 21:52:53,680
so examples of security incidents
30459
21:52:54,784 --> 21:52:55,784
include unauthorized access to data
30460
21:52:57,720 --> 21:52:58,720
attacks through malware or denial of
30461
21:53:00,000 --> 21:53:01,000
service
30462
21:53:01,504 --> 21:53:02,504
it's important to understand the
30463
21:53:03,120 --> 21:53:04,120
technical and legal aspects in order to
30464
21:53:05,160 --> 21:53:06,160
gather information because you could be
30465
21:53:08,400 --> 21:53:09,400
will cover first responder in a bit but
30466
21:53:10,744 --> 21:53:11,744
you that could be you
30467
21:53:12,960 --> 21:53:13,960
could be contacted by a law enforcement
30468
21:53:15,360 --> 21:53:16,360
agency told us some sort of um data or
30469
21:53:20,512 --> 21:53:21,512
even their Hardware that's been involved
30470
21:53:23,576 --> 21:53:24,576
in the commission of a crime and be
30471
21:53:25,440 --> 21:53:26,440
asked to take certain steps or be served
30472
21:53:27,960 --> 21:53:28,960
with the legal notice for criminal or
30473
21:53:30,656 --> 21:53:31,656
civil court
30474
21:53:32,104 --> 21:53:33,104
the risk is if you don't have these
30475
21:53:34,256 --> 21:53:35,256
forensic processes you could lose your
30476
21:53:37,376 --> 21:53:38,376
um evidence or it could become
30477
21:53:39,176 --> 21:53:40,176
inadmissible which can be quite
30478
21:53:40,696 --> 21:53:41,696
embarrassing because
30479
21:53:42,656 --> 21:53:43,656
um it could I mean the cases last
30480
21:53:45,296 --> 21:53:46,296
the security professional needs to know
30481
21:53:48,000 --> 21:53:49,000
the legal aspects
30482
21:53:49,680 --> 21:53:50,680
so U.S law mandates proper authorization
30483
21:53:52,144 --> 21:53:53,144
must be acquired before Security
30484
21:53:54,536 --> 21:53:55,536
Professionals can monitor and gather
30485
21:53:56,400 --> 21:53:57,400
information so it depends what it is
30486
21:53:58,744 --> 21:53:59,744
you'd be certain sort of court order or
30487
21:54:00,896 --> 21:54:01,896
warrant
30488
21:54:02,104 --> 21:54:03,104
and in the form of a paperwork in order
30489
21:54:05,464 --> 21:54:06,464
to um take certain action or preserve a
30490
21:54:08,576 --> 21:54:09,576
certain amount of evidence or hand it
30491
21:54:10,016 --> 21:54:11,016
over
30492
21:54:11,336 --> 21:54:12,336
uh organization should have a computer
30493
21:54:13,144 --> 21:54:14,144
forensic competence established as part
30494
21:54:15,424 --> 21:54:16,424
of its security policy and you may need
30495
21:54:19,080 --> 21:54:20,080
to have it in respect of having audits
30496
21:54:21,832 --> 21:54:22,832
for compliance or certification to work
30497
21:54:24,536 --> 21:54:25,536
with certain vendors or government
30498
21:54:26,512 --> 21:54:27,512
departments
30499
21:54:28,920 --> 21:54:29,920
so the first responder is a person first
30500
21:54:31,376 --> 21:54:32,376
to be present on the scene after the
30501
21:54:32,936 --> 21:54:33,936
occurrence of a security incident which
30502
21:54:34,856 --> 21:54:35,856
if you're the duty network engineer then
30503
21:54:37,680 --> 21:54:38,680
that could well mean you
30504
21:54:40,552 --> 21:54:41,552
um you control the damage caused by the
30505
21:54:42,120 --> 21:54:43,120
incident and ensure none of the evidence
30506
21:54:44,160 --> 21:54:45,160
is spoiled to the best durability
30507
21:54:47,216 --> 21:54:48,216
first responder initiates the escalation
30508
21:54:49,440 --> 21:54:50,440
procedure so you'd inform um
30509
21:54:52,744 --> 21:54:53,744
the legal authorities whoever that may
30510
21:54:54,832 --> 21:54:55,832
be and um internal company management
30511
21:54:57,960 --> 21:54:58,960
and bosses
30512
21:55:01,640 --> 21:55:02,640
e-discovery or electronic Discovery
30513
21:55:03,896 --> 21:55:04,896
refers to a pre-trial procedure where
30514
21:55:06,360 --> 21:55:07,360
the parties exchange the electronically
30515
21:55:08,576 --> 21:55:09,576
installed information this could be
30516
21:55:10,800 --> 21:55:11,800
emails exchanged between different
30517
21:55:13,552 --> 21:55:14,552
employees it could be spreadsheets a
30518
21:55:17,104 --> 21:55:18,104
video conference calls that have been
30519
21:55:18,896 --> 21:55:19,896
recorded
30520
21:55:20,760 --> 21:55:21,760
um anything electronically really that's
30521
21:55:22,680 --> 21:55:23,680
pertinent to the case
30522
21:55:24,832 --> 21:55:25,832
and it's different from paper documents
30523
21:55:26,640 --> 21:55:27,640
because it's not actually tangible
30524
21:55:29,104 --> 21:55:30,104
um and it could obviously be saved in
30525
21:55:31,256 --> 21:55:32,256
one place or saved in multiple places
30526
21:55:33,296 --> 21:55:34,296
over the cloud and have different
30527
21:55:35,160 --> 21:55:36,160
versions of it
30528
21:55:37,144 --> 21:55:38,144
some examples for electronically stalled
30529
21:55:40,256 --> 21:55:41,256
information are as follows
30530
21:55:43,976 --> 21:55:44,976
emails voicemails documents
30531
21:55:46,016 --> 21:55:47,016
presentations databases websites and it
30532
21:55:49,016 --> 21:55:50,016
could be for a certain period like a
30533
21:55:51,960 --> 21:55:52,960
database copy of a database from a month
30534
21:55:55,256 --> 21:55:56,256
ago or a year ago or whatever it
30535
21:55:58,256 --> 21:55:59,256
obviously varies
30536
21:56:00,056 --> 21:56:01,056
the electronic Discovery process this
30537
21:56:02,824 --> 21:56:03,824
involves identifying preserving
30538
21:56:05,160 --> 21:56:06,160
collecting processing reviewing and
30539
21:56:07,016 --> 21:56:08,016
producing the document to the opposing
30540
21:56:09,600 --> 21:56:10,600
Council
30541
21:56:10,856 --> 21:56:11,856
you could actually have to produce it
30542
21:56:12,960 --> 21:56:13,960
for your own lawyers as well and to
30543
21:56:15,480 --> 21:56:16,480
prove your case
30544
21:56:18,656 --> 21:56:19,656
now the gender custody is a document and
30545
21:56:21,480 --> 21:56:22,480
you could have evidence labels if it's a
30546
21:56:23,872 --> 21:56:24,872
physical hard drive for example and this
30547
21:56:26,640 --> 21:56:27,640
would include the person who seized it
30548
21:56:28,320 --> 21:56:29,320
who they handed it to
30549
21:56:30,600 --> 21:56:31,600
um I'll go into some of the stuff on the
30550
21:56:31,976 --> 21:56:32,976
next slide
30551
21:56:33,480 --> 21:56:34,480
let's um let you know the location of
30552
21:56:36,000 --> 21:56:37,000
the evidence so if it's finally handed
30553
21:56:37,440 --> 21:56:38,440
to a and property
30554
21:56:40,320 --> 21:56:41,320
retention department like in the police
30555
21:56:42,656 --> 21:56:43,656
property area
30556
21:56:44,696 --> 21:56:45,696
then um that would be the last person to
30557
21:56:46,856 --> 21:56:47,856
have signed for possession
30558
21:56:49,376 --> 21:56:50,376
starts when it was collected
30559
21:56:51,976 --> 21:56:52,976
requires who collected it the date and
30560
21:56:54,720 --> 21:56:55,720
time description where the evidence was
30561
21:56:57,656 --> 21:56:58,656
stored it's not only given an exhibit
30562
21:56:59,336 --> 21:57:00,336
reference as well certainly if it's
30563
21:57:01,504 --> 21:57:02,504
collected by an experienced
30564
21:57:03,424 --> 21:57:04,424
um forensics person it'll have some
30565
21:57:05,280 --> 21:57:06,280
reference number on it
30566
21:57:09,240 --> 21:57:10,240
um how it was initially secured which
30567
21:57:11,104 --> 21:57:12,104
software can be used to view it
30568
21:57:13,256 --> 21:57:14,256
the transfer history the evidence and
30569
21:57:15,360 --> 21:57:16,360
here's some evidence labels
30570
21:57:17,936 --> 21:57:18,936
and not necessarily just for um
30571
21:57:21,000 --> 21:57:22,000
Okay computer forensics if you can see
30572
21:57:23,280 --> 21:57:24,280
on the left it's received from and by
30573
21:57:25,856 --> 21:57:26,856
date time the agency the case number the
30574
21:57:29,104 --> 21:57:30,104
badge number
30575
21:57:31,016 --> 21:57:32,016
and then on the right the submitting
30576
21:57:33,056 --> 21:57:34,056
agency again and chain of custody
30577
21:57:38,464 --> 21:57:39,464
so the child across today is the
30578
21:57:40,440 --> 21:57:41,440
transfer history showing the information
30579
21:57:41,760 --> 21:57:42,760
every person or every normally person
30580
21:57:45,656 --> 21:57:46,656
could be a department and along with the
30581
21:57:48,000 --> 21:57:49,000
names and the person signed in the dates
30582
21:57:50,696 --> 21:57:51,696
and where the evidence was stored and
30583
21:57:52,256 --> 21:57:53,256
secured
30584
21:57:54,480 --> 21:57:55,480
now if there's a problem if person a has
30585
21:57:58,976 --> 21:57:59,976
signed it person B assigned it and then
30586
21:58:01,616 --> 21:58:02,616
person D signs a label we've missed out
30587
21:58:04,440 --> 21:58:05,440
what happened one person C held that
30588
21:58:06,960 --> 21:58:07,960
evidence and if the chain of custody is
30589
21:58:09,240 --> 21:58:10,240
like broken it means the evidence could
30590
21:58:11,824 --> 21:58:12,824
be tampered with and then it'll be down
30591
21:58:13,680 --> 21:58:14,680
to a court to determine whether or not
30592
21:58:15,896 --> 21:58:16,896
that evidence is still admissible
30593
21:58:19,856 --> 21:58:20,856
and the evidence
30594
21:58:21,480 --> 21:58:22,480
um but I've just said that it may not be
30595
21:58:23,040 --> 21:58:24,040
admissible it could be useless in court
30596
21:58:25,080 --> 21:58:26,080
all right there's a document or a
30597
21:58:27,120 --> 21:58:28,120
process called Legal holds used in
30598
21:58:29,872 --> 21:58:30,872
litigation but it could also be a
30599
21:58:31,504 --> 21:58:32,504
preservation order basically requires an
30600
21:58:34,256 --> 21:58:35,256
individual or organization to preserve
30601
21:58:37,144 --> 21:58:38,144
all information that may be required by
30602
21:58:39,784 --> 21:58:40,784
an opposing party because of anticipated
30603
21:58:42,536 --> 21:58:43,536
litigation
30604
21:58:46,376 --> 21:58:47,376
data should be preserved such as emails
30605
21:58:49,680 --> 21:58:50,680
um preventing things being deleted
30606
21:58:52,256 --> 21:58:53,256
because of um a certain period of time
30607
21:58:55,616 --> 21:58:56,616
has um transpired or expired sorry
30608
21:58:59,696 --> 21:59:00,696
and there's an Interventional hold on
30609
21:59:01,856 --> 21:59:02,856
the routine destruction until the
30610
21:59:03,720 --> 21:59:04,720
litigation end so you know as backups
30611
21:59:06,536 --> 21:59:07,536
normally get wiped
30612
21:59:08,336 --> 21:59:09,336
and um replaced with fresher backups
30613
21:59:11,936 --> 21:59:12,936
then um you wouldn't be able to do that
30614
21:59:13,680 --> 21:59:14,680
you'd have to keep hold of the evidence
30615
21:59:16,496 --> 21:59:17,496
if a crime scene is a physical location
30616
21:59:18,176 --> 21:59:19,176
then the area should be first secured
30617
21:59:20,336 --> 21:59:21,336
once the area is secured is important
30618
21:59:22,320 --> 21:59:23,320
together as much evidence as possible
30619
21:59:24,960 --> 21:59:25,960
normally this person will be properly
30620
21:59:27,056 --> 21:59:28,056
trained and qualified and just to go
30621
21:59:30,056 --> 21:59:31,056
through how the evidence is collected
30622
21:59:32,176 --> 21:59:33,176
photographed preserved and who it's
30623
21:59:34,256 --> 21:59:35,256
handed on to and in what manner and some
30624
21:59:37,376 --> 21:59:38,376
types of evidence and not that it
30625
21:59:39,240 --> 21:59:40,240
applies to computers but
30626
21:59:41,936 --> 21:59:42,936
um say blood on clothing that has to be
30627
21:59:44,600 --> 21:59:45,600
dried in a certain way in order for it
30628
21:59:47,640 --> 21:59:48,640
not to um all go stale and lose all the
30629
21:59:51,056 --> 21:59:52,056
DNA evidence
30630
21:59:54,720 --> 21:59:55,720
if the crimes are cyber crime and then
30631
21:59:56,936 --> 21:59:57,936
the location should be secured to stop
30632
21:59:59,464 --> 22:00:00,464
the evidence being tampered with
30633
22:00:01,744 --> 22:00:02,744
it doesn't mention there but obviously
30634
22:00:03,424 --> 22:00:04,424
if there's remote access available to
30635
22:00:05,280 --> 22:00:06,280
the device that has to be born in mind
30636
22:00:07,192 --> 22:00:08,192
as well in case somebody can
30637
22:00:08,720 --> 22:00:09,720
inadvertently log in and wipe the
30638
22:00:10,856 --> 22:00:11,856
information
30639
22:00:13,320 --> 22:00:14,320
a hard drive should be kept in a secure
30640
22:00:15,424 --> 22:00:16,424
Drive is probably going to become harder
30641
22:00:17,280 --> 22:00:18,280
and harder
30642
22:00:18,240 --> 22:00:19,240
now we're using cloud computing
30643
22:00:22,080 --> 22:00:23,080
uh collect all
30644
22:00:24,480 --> 22:00:25,480
um digital evidence in a manner
30645
22:00:26,280 --> 22:00:27,280
permissible to the court it depends on
30646
22:00:28,376 --> 22:00:29,376
the court obviously
30647
22:00:30,296 --> 22:00:31,296
when Crumbs are committed the first
30648
22:00:31,920 --> 22:00:32,920
responder at the scene controls the
30649
22:00:34,920 --> 22:00:35,920
damage this could well be you as I've
30650
22:00:36,960 --> 22:00:37,960
said so down to you to use your
30651
22:00:38,760 --> 22:00:39,760
technical know-how to preserve data as
30652
22:00:41,160 --> 22:00:42,160
much as possible
30653
22:00:42,960 --> 22:00:43,960
foreign
30654
22:00:44,104 --> 22:00:45,104
ensure nobody else tampers with it again
30655
22:00:46,920 --> 22:00:47,920
you'll be advised by law enforcement as
30656
22:00:49,616 --> 22:00:50,616
and when they arrive but down to you to
30657
22:00:51,600 --> 22:00:52,600
stop people walking all over things or
30658
22:00:54,360 --> 22:00:55,360
picking them up or moving them which
30659
22:00:55,920 --> 22:00:56,920
have seen happen when I was in the
30660
22:00:58,080 --> 22:00:59,080
police
30661
22:01:01,144 --> 22:01:02,144
during the course of the investigation
30662
22:01:02,760 --> 22:01:03,760
the investigators collect as much
30663
22:01:05,160 --> 22:01:06,160
evidence as possible
30664
22:01:07,144 --> 22:01:08,144
the technical city is established from
30665
22:01:08,872 --> 22:01:09,872
the moment of the initial collection
30666
22:01:10,376 --> 22:01:11,376
until the investigation finally ends if
30667
22:01:13,376 --> 22:01:14,376
it has to be transported the data in
30668
22:01:16,016 --> 22:01:17,016
some way it should be done so securely
30669
22:01:18,176 --> 22:01:19,176
to prevent tampering again this is the
30670
22:01:20,040 --> 22:01:21,040
chain of custody
30671
22:01:22,256 --> 22:01:23,256
uh when the investigations finally
30672
22:01:24,360 --> 22:01:25,360
complete the forensic report is made
30673
22:01:26,104 --> 22:01:27,104
available in a format that can be
30674
22:01:28,496 --> 22:01:29,496
understood by non-technical person and
30675
22:01:31,552 --> 22:01:32,552
normally because it's been presented to
30676
22:01:33,000 --> 22:01:34,000
the jewelry if it goes to um a jury
30677
22:01:35,640 --> 22:01:36,640
trial
30678
22:01:37,976 --> 22:01:38,976
okay we've mentioned um the legal hold
30679
22:01:40,320 --> 22:01:41,320
must keep that information into the
30680
22:01:42,536 --> 22:01:43,536
litigation ends
30681
22:01:44,512 --> 22:01:45,512
just a few steps in the basic forensic
30682
22:01:46,976 --> 22:01:47,976
process
30683
22:01:49,192 --> 22:01:50,192
this should be a process in place
30684
22:01:51,480 --> 22:01:52,480
according to National Institute of
30685
22:01:53,400 --> 22:01:54,400
Standards and Technology
30686
22:01:55,552 --> 22:01:56,552
the following steps collection
30687
22:01:57,784 --> 22:01:58,784
examination analysis and Reporting
30688
22:02:02,640 --> 22:02:03,640
collection is the first phase where data
30689
22:02:04,976 --> 22:02:05,976
is identified labels and recorded and
30690
22:02:07,976 --> 22:02:08,976
gathered
30691
22:02:09,424 --> 22:02:10,424
could well be photographed in situ also
30692
22:02:12,256 --> 22:02:13,256
examination uh it's the data's
30693
22:02:15,360 --> 22:02:16,360
forensically process using automated or
30694
22:02:17,640 --> 22:02:18,640
manual methods
30695
22:02:19,256 --> 22:02:20,256
analysis the results of the examination
30696
22:02:22,320 --> 22:02:23,320
are analyzed to get answers
30697
22:02:24,896 --> 22:02:25,896
and then reporting the results are
30698
22:02:27,896 --> 22:02:28,896
reported
30699
22:02:29,600 --> 22:02:30,600
details the actions carried out the
30700
22:02:32,104 --> 22:02:33,104
tools and procedure used who did it and
30701
22:02:34,256 --> 22:02:35,256
when and why
30702
22:02:36,536 --> 22:02:37,536
Okay so we've covered a lot here so just
30703
22:02:38,512 --> 22:02:39,512
to recap we've looked at forensics and
30704
22:02:40,616 --> 22:02:41,616
computer forensics
30705
22:02:42,176 --> 22:02:43,176
the first responder
30706
22:02:44,176 --> 22:02:45,176
electronic Discovery in the chain of
30707
22:02:46,680 --> 22:02:47,680
custody
30708
22:02:47,824 --> 22:02:48,824
legal holes securing the crime scene
30709
22:02:51,656 --> 22:02:52,656
the high level View
30710
22:02:54,296 --> 22:02:55,296
steps in basic uh forensics collection
30711
22:02:57,536 --> 22:02:58,536
examination analysis and Reporting so
30712
22:03:00,784 --> 22:03:01,784
that's all for now thanks for watching
30713
22:03:09,130 --> 22:03:10,130
[Music]
30714
22:03:17,832 --> 22:03:18,832
thank you
30715
22:03:25,376 --> 22:03:26,376
welcome to module 18 lesson 3 safety
30716
22:03:28,552 --> 22:03:29,552
practices
30717
22:03:30,176 --> 22:03:31,176
another new addition to the topic and
30718
22:03:34,144 --> 22:03:35,144
it's something that has been growing
30719
22:03:36,360 --> 22:03:37,360
over the past few years and so this has
30720
22:03:38,104 --> 22:03:39,104
become a recognized area where you go
30721
22:03:41,512 --> 22:03:42,512
and get qualified in a risk assessment
30722
22:03:44,336 --> 22:03:45,336
or whatever it's called in your
30723
22:03:46,016 --> 22:03:47,016
respective countries
30724
22:03:47,696 --> 22:03:48,696
in respect of
30725
22:03:49,920 --> 22:03:50,920
um certainly data centers the safe
30726
22:03:52,192 --> 22:03:53,192
storage
30727
22:03:54,480 --> 22:03:55,480
um manual handling what to do in the
30728
22:03:57,424 --> 22:03:58,424
event of an emergency a fire or other
30729
22:03:59,512 --> 22:04:00,512
disaster how to keep
30730
22:04:02,280 --> 22:04:03,280
um the equipment safe and comply with
30731
22:04:05,696 --> 22:04:06,696
all of the
30732
22:04:07,440 --> 22:04:08,440
um different certifications and if you
30733
22:04:09,896 --> 22:04:10,896
want to be a Data Center
30734
22:04:11,480 --> 22:04:12,480
and keep people safe also
30735
22:04:15,536 --> 22:04:16,536
so look at the data center and the need
30736
22:04:18,296 --> 22:04:19,296
the environment heating ventilation and
30737
22:04:21,120 --> 22:04:22,120
cooling HVAC
30738
22:04:23,160 --> 22:04:24,160
how HVAC works
30739
22:04:25,744 --> 22:04:26,744
typical hot cold oil conditions
30740
22:04:28,920 --> 22:04:29,920
rack mount servers rack loading
30741
22:04:32,160 --> 22:04:33,160
power distribution and fire risk
30742
22:04:35,640 --> 22:04:36,640
the impact of Fire
30743
22:04:38,160 --> 22:04:39,160
types of their suppressant agents you've
30744
22:04:40,376 --> 22:04:41,376
got available to install wet pipe dry
30745
22:04:43,920 --> 22:04:44,920
pipe and gas
30746
22:04:45,656 --> 22:04:46,656
how to lift stuff up without getting
30747
22:04:47,576 --> 22:04:48,576
injured anti-static it's funnily enough
30748
22:04:50,400 --> 22:04:51,400
anti-static if people laugh about it and
30749
22:04:52,552 --> 22:04:53,552
don't think about it but it can actually
30750
22:04:54,240 --> 22:04:55,240
fry vital components in your devices
30751
22:04:58,192 --> 22:04:59,192
stabilizing the Iraq and the material
30752
22:05:00,656 --> 22:05:01,656
safety data sheet which is another
30753
22:05:03,080 --> 22:05:04,080
item added to the syllabus the MSDS
30754
22:05:07,440 --> 22:05:08,440
all right I'm sure you've heard the data
30755
22:05:09,120 --> 22:05:10,120
centers and if you're very lucky you've
30756
22:05:10,920 --> 22:05:11,920
actually got to work in one or will be
30757
22:05:13,016 --> 22:05:14,016
working in one great place to work
30758
22:05:16,856 --> 22:05:17,856
there's a definition on Wikipedia it's a
30759
22:05:19,680 --> 22:05:20,680
facilities used to house computer
30760
22:05:21,600 --> 22:05:22,600
systems and Associated components such
30761
22:05:23,760 --> 22:05:24,760
as telecoms and Storage
30762
22:05:26,576 --> 22:05:27,576
generally includes redundant backup
30763
22:05:28,680 --> 22:05:29,680
power supplies Communications
30764
22:05:30,720 --> 22:05:31,720
environmental controls
30765
22:05:33,056 --> 22:05:34,056
EG air conditioning fire suppression and
30766
22:05:35,696 --> 22:05:36,696
various security devices
30767
22:05:40,144 --> 22:05:41,144
why do we bother it basically helps
30768
22:05:41,872 --> 22:05:42,872
organization centralize the entire
30769
22:05:44,120 --> 22:05:45,120
Computing resources into one location
30770
22:05:47,512 --> 22:05:48,512
where they can have a uniform procedure
30771
22:05:51,296 --> 22:05:52,296
for insulation upgrades out of hours a
30772
22:05:55,680 --> 22:05:56,680
redundancy a whole bunch of stuff
30773
22:05:58,496 --> 22:05:59,496
uh reduces the TCO by consolidating all
30774
22:06:02,104 --> 22:06:03,104
your power and cooling otherwise you'd
30775
22:06:03,656 --> 22:06:04,656
have to have 10 20 30 40 racks spread
30776
22:06:07,144 --> 22:06:08,144
among different departments or different
30777
22:06:09,176 --> 22:06:10,176
buildings or different cities making
30778
22:06:10,976 --> 22:06:11,976
things pretty difficult to control
30779
22:06:15,120 --> 22:06:16,120
racks and rackmatic servers are used in
30780
22:06:17,576 --> 22:06:18,576
data centers at the moment I'm sure the
30781
22:06:20,512 --> 22:06:21,512
future will uh have something completely
30782
22:06:22,320 --> 22:06:23,320
different you've got the servers storage
30783
22:06:24,784 --> 22:06:25,784
arrays and power distribution units all
30784
22:06:27,832 --> 22:06:28,832
the other devices and internal
30785
22:06:30,120 --> 22:06:31,120
components generate a lot of heat
30786
22:06:34,376 --> 22:06:35,376
the heat needs to be removed because it
30787
22:06:36,296 --> 22:06:37,296
obviously affects the electric equipment
30788
22:06:38,216 --> 22:06:39,216
to the point where it reaches a
30789
22:06:40,680 --> 22:06:41,680
threshold that it can no longer function
30790
22:06:43,400 --> 22:06:44,400
and then the device will fail and you
30791
22:06:46,192 --> 22:06:47,192
may have had this on your home computer
30792
22:06:47,696 --> 22:06:48,696
if your CPU fan
30793
22:06:49,920 --> 22:06:50,920
has stopped working or this tumors dust
30794
22:06:52,256 --> 22:06:53,256
or dirt inside your equipment then it
30795
22:06:55,680 --> 22:06:56,680
starts to lock up and finally fail I
30796
22:06:59,336 --> 22:07:00,336
know that's happened to me
30797
22:07:02,280 --> 22:07:03,280
since heat effects of reliability we
30798
22:07:04,192 --> 22:07:05,192
need to keep it cool this requires
30799
22:07:06,536 --> 22:07:07,536
removing the hot air and moving in cold
30800
22:07:09,960 --> 22:07:10,960
air just like your PC chassis but on a
30801
22:07:12,480 --> 22:07:13,480
much larger scale
30802
22:07:13,800 --> 22:07:14,800
I'll turn cold air within the data
30803
22:07:15,656 --> 22:07:16,656
center shouldn't be mixed and for this
30804
22:07:17,936 --> 22:07:18,936
reason you've got the hot oil and the
30805
22:07:19,616 --> 22:07:20,616
cold oil Arrangement this is for your
30806
22:07:22,376 --> 22:07:23,376
ventilation
30807
22:07:25,016 --> 22:07:26,016
if the cold air mixes with a hot air
30808
22:07:26,824 --> 22:07:27,824
without going through the equipment then
30809
22:07:28,144 --> 22:07:29,144
it becomes useless
30810
22:07:31,856 --> 22:07:32,856
so HVAC stands for heating ventilation
30811
22:07:34,192 --> 22:07:35,192
and cooling which is an entire set of
30812
22:07:36,784 --> 22:07:37,784
systems procedures best practices and
30813
22:07:39,480 --> 22:07:40,480
companies that will help you plan and
30814
22:07:41,400 --> 22:07:42,400
manage and install all of this
30815
22:07:43,552 --> 22:07:44,552
provides the optimum temperature and
30816
22:07:45,656 --> 22:07:46,656
indoor air quality so you've obviously
30817
22:07:47,936 --> 22:07:48,936
got to have an environment that works
30818
22:07:49,504 --> 22:07:50,504
best for the equipment but also the
30819
22:07:51,960 --> 22:07:52,960
engineers can go in and manage and
30820
22:07:53,936 --> 22:07:54,936
survive in
30821
22:07:55,440 --> 22:07:56,440
the HVAC system not only keeps things
30822
22:07:57,360 --> 22:07:58,360
cool and keeps things humid obviously
30823
22:07:59,696 --> 22:08:00,696
not too humid but there has to be a
30824
22:08:01,744 --> 22:08:02,744
certain level of humidity in there and
30825
22:08:04,376 --> 22:08:05,376
removes contaminants from the air also
30826
22:08:08,872 --> 22:08:09,872
cold air is pumped from the HVAC system
30827
22:08:11,160 --> 22:08:12,160
into the cold aisle as an as an input
30828
22:08:13,976 --> 22:08:14,976
for the servers
30829
22:08:15,720 --> 22:08:16,720
the server is pulling cold air from the
30830
22:08:17,576 --> 22:08:18,576
front to cool themselves and they
30831
22:08:19,504 --> 22:08:20,504
exhaust hot air which goes into the hot
30832
22:08:21,896 --> 22:08:22,896
tile
30833
22:08:23,040 --> 22:08:24,040
now my experience when I've gone to Data
30834
22:08:25,552 --> 22:08:26,552
Centers is the the better ones I've got
30835
22:08:28,552 --> 22:08:29,552
doors to get in and out of the cool
30836
22:08:31,144 --> 22:08:32,144
aisle
30837
22:08:32,160 --> 22:08:33,160
the Hostile
30838
22:08:33,720 --> 22:08:34,720
um they're certainly the ones I've been
30839
22:08:34,920 --> 22:08:35,920
to don't have the doors so you'll be
30840
22:08:37,376 --> 22:08:38,376
walking through an area that feels quite
30841
22:08:39,000 --> 22:08:40,000
warm you'll open the door to go to the
30842
22:08:41,104 --> 22:08:42,104
front of the servers to connect or do
30843
22:08:43,552 --> 22:08:44,552
whatever obviously shooting the door
30844
22:08:45,000 --> 22:08:46,000
behind you and it'll be very cool in
30845
22:08:48,000 --> 22:08:49,000
fact you'll probably need to wear a
30846
22:08:49,192 --> 22:08:50,192
couple of layers of clothing
30847
22:08:51,480 --> 22:08:52,480
the AC duct carries the hot air from the
30848
22:08:53,936 --> 22:08:54,936
hotel to the HVAC to cool it again and
30849
22:08:56,872 --> 22:08:57,872
exhaust it elsewhere
30850
22:09:00,296 --> 22:09:01,296
typical hot cold oil conditions the cold
30851
22:09:03,720 --> 22:09:04,720
air temperatures range from 55 to 78
30852
22:09:06,176 --> 22:09:07,176
Fahrenheit they haven't listed this in
30853
22:09:08,400 --> 22:09:09,400
Celsius so I presume this is for the
30854
22:09:10,376 --> 22:09:11,376
American viewers the hot oil temperature
30855
22:09:12,960 --> 22:09:13,960
goes from 73 to 96 Fahrenheit
30856
22:09:16,856 --> 22:09:17,856
and the amount of heat carried by the
30857
22:09:18,600 --> 22:09:19,600
stream of air exiting the heat load
30858
22:09:20,576 --> 22:09:21,576
should be 15 to 20 degrees Fahrenheit
30859
22:09:24,056 --> 22:09:25,056
rack mount servers I don't know if
30860
22:09:26,400 --> 22:09:27,400
you've seen many of these I've seen a
30861
22:09:27,832 --> 22:09:28,832
lot over the years the rack contains the
30862
22:09:31,080 --> 22:09:32,080
servers the servers have a different
30863
22:09:32,760 --> 22:09:33,760
form factor than your normal desktop
30864
22:09:34,760 --> 22:09:35,760
servers these are these obviously need
30865
22:09:37,440 --> 22:09:38,440
to be
30866
22:09:38,424 --> 22:09:39,424
compliant to fit into a rack taking over
30867
22:09:42,240 --> 22:09:43,240
so many
30868
22:09:43,800 --> 22:09:44,800
um units uh use they call it sometimes
30869
22:09:46,616 --> 22:09:47,616
one two and so on
30870
22:09:49,376 --> 22:09:50,376
they need to have the correct eyes so
30871
22:09:52,256 --> 22:09:53,256
you can screw in the screws to hold it
30872
22:09:54,056 --> 22:09:55,056
into place securely front and back and
30873
22:09:56,760 --> 22:09:57,760
most of them actually you can pull open
30874
22:09:59,936 --> 22:10:00,936
so it pulls out from the rest and you
30875
22:10:02,872 --> 22:10:03,872
can do various things without having to
30876
22:10:04,496 --> 22:10:05,496
shut down the server or the cables
30877
22:10:07,256 --> 22:10:08,256
coming loose larger up Mount servers and
30878
22:10:09,720 --> 22:10:10,720
Equipment are stored at the bottom so
30879
22:10:11,160 --> 22:10:12,160
the heavier stuff at the bottom to
30880
22:10:12,896 --> 22:10:13,896
ensure the rack doesn't tip over
30881
22:10:15,120 --> 22:10:16,120
Rock loading should not only seed the
30882
22:10:17,824 --> 22:10:18,824
weight rated capacity of the raised
30883
22:10:20,464 --> 22:10:21,464
floor to ensure that the race floor
30884
22:10:22,192 --> 22:10:23,192
doesn't collapse because it's
30885
22:10:23,464 --> 22:10:24,464
overweighted everything has to be
30886
22:10:25,552 --> 22:10:26,552
documented planned and measured so you
30887
22:10:28,256 --> 22:10:29,256
spread load over inside one rack and
30888
22:10:31,856 --> 22:10:32,856
among a multitude of racks so you can
30889
22:10:34,680 --> 22:10:35,680
have the heavier stuff going at the
30890
22:10:36,240 --> 22:10:37,240
bottom of 10 different racks the next
30891
22:10:38,696 --> 22:10:39,696
heaviest goes on top on 10 different
30892
22:10:41,104 --> 22:10:42,104
racks and so on rather than having one
30893
22:10:43,856 --> 22:10:44,856
rack with all the heavier stuff because
30894
22:10:45,832 --> 22:10:46,832
it could if it breaches a loading it's
30895
22:10:47,824 --> 22:10:48,824
obviously going to break through the
30896
22:10:48,832 --> 22:10:49,832
floor
30897
22:10:50,872 --> 22:10:51,872
uh the power distribution your data
30898
22:10:52,920 --> 22:10:53,920
center is normally connected to multiple
30899
22:10:54,424 --> 22:10:55,424
power grids
30900
22:10:55,800 --> 22:10:56,800
um and even after that you could have
30901
22:10:57,656 --> 22:10:58,656
the one the one I used to have my
30902
22:10:59,336 --> 22:11:00,336
equipment at had
30903
22:11:01,376 --> 22:11:02,376
um
30904
22:11:02,040 --> 22:11:03,040
massive generators that would take over
30905
22:11:04,192 --> 22:11:05,192
and it wasn't one generator the
30906
22:11:05,824 --> 22:11:06,824
generator had a backup generator as well
30907
22:11:07,920 --> 22:11:08,920
so there's three levels of redundancy in
30908
22:11:11,040 --> 22:11:12,040
case there was a power cut for whatever
30909
22:11:12,960 --> 22:11:13,960
reason
30910
22:11:14,400 --> 22:11:15,400
if you've got two grids if power is lost
30911
22:11:16,496 --> 22:11:17,496
on one grid and certainly where I live
30912
22:11:18,360 --> 22:11:19,360
in Australia you get power Cuts quite
30913
22:11:21,056 --> 22:11:22,056
regularly which is a strange phenomenon
30914
22:11:25,192 --> 22:11:26,192
now to experience
30915
22:11:27,176 --> 22:11:28,176
nowadays for devices with redundant
30916
22:11:29,936 --> 22:11:30,936
power supplies power comes from separate
30917
22:11:31,800 --> 22:11:32,800
circuits providing redundancy
30918
22:11:34,800 --> 22:11:35,800
so it would be
30919
22:11:37,320 --> 22:11:38,320
um it wouldn't be great redundancy to
30920
22:11:39,056 --> 22:11:40,056
have your redundant power supply both
30921
22:11:40,552 --> 22:11:41,552
connected to the same extension lead
30922
22:11:43,440 --> 22:11:44,440
because if the
30923
22:11:45,120 --> 22:11:46,120
extension lead goes down or the power
30924
22:11:47,336 --> 22:11:48,336
supply providing power to the extension
30925
22:11:49,800 --> 22:11:50,800
lead then you lose both your power
30926
22:11:51,360 --> 22:11:52,360
supplies redundant and Main
30927
22:11:54,480 --> 22:11:55,480
as a data centers power requirements are
30928
22:11:57,536 --> 22:11:58,536
determined by taking into account the
30929
22:11:59,280 --> 22:12:00,280
power requirements of all the equipment
30930
22:12:01,680 --> 22:12:02,680
and you've got a feature
30931
22:12:04,376 --> 22:12:05,376
um future growth so you can't just plan
30932
22:12:06,832 --> 22:12:07,832
for what you need now you need to plan
30933
22:12:09,536 --> 22:12:10,536
for however many years in the future in
30934
22:12:12,600 --> 22:12:13,600
the company's business plan
30935
22:12:15,120 --> 22:12:16,120
uh you need to ground all equipment
30936
22:12:17,160 --> 22:12:18,160
separate to
30937
22:12:18,960 --> 22:12:19,960
um other grounds
30938
22:12:22,016 --> 22:12:23,016
fire and demand for the power increases
30939
22:12:25,016 --> 22:12:26,016
with the
30940
22:12:26,336 --> 22:12:27,336
um amount of equipment a lot of the
30941
22:12:28,976 --> 22:12:29,976
cream equipment with increased power
30942
22:12:30,616 --> 22:12:31,616
consumption I can find a small spaces
30943
22:12:34,192 --> 22:12:35,192
and susceptible to fire accidents
30944
22:12:37,192 --> 22:12:38,192
again this is down there due to heat
30945
22:12:39,256 --> 22:12:40,256
obviously fire will be catastrophic
30946
22:12:44,280 --> 22:12:45,280
data centers are fire detection systems
30947
22:12:46,680 --> 22:12:47,680
that detect the fires where they detect
30948
22:12:48,424 --> 22:12:49,424
smoke I think before the fire
30949
22:12:50,512 --> 22:12:51,512
you've got portable fire extinguishers
30950
22:12:52,616 --> 22:12:53,616
for engineers to use if they
30951
22:12:55,320 --> 22:12:56,320
somehow set something on fire or see a
30952
22:12:57,960 --> 22:12:58,960
small fire
30953
22:12:59,216 --> 22:13:00,216
data centers have emergency power off
30954
22:13:01,440 --> 22:13:02,440
switches which are big red patents on
30955
22:13:03,296 --> 22:13:04,296
the wall that cut off all power
30956
22:13:08,104 --> 22:13:09,104
obviously if you do that it's um a
30957
22:13:11,536 --> 22:13:12,536
constitutes an emergency because all the
30958
22:13:14,104 --> 22:13:15,104
servers don't really um deal with hard
30959
22:13:17,216 --> 22:13:18,216
power shutdowns very well they normally
30960
22:13:18,960 --> 22:13:19,960
need to be correctly um shut down
30961
22:13:21,440 --> 22:13:22,440
following procedures faster person
30962
22:13:24,424 --> 22:13:25,424
agents put out the fire
30963
22:13:26,336 --> 22:13:27,336
you've got to choose the correct one
30964
22:13:28,376 --> 22:13:29,376
obviously if you even if you go to a
30965
22:13:30,424 --> 22:13:31,424
local hardware store and choose a fire
30966
22:13:32,280 --> 22:13:33,280
extinguisher there's some for um the
30967
22:13:34,976 --> 22:13:35,976
kitchen some for papers and some for car
30968
22:13:37,744 --> 22:13:38,744
fires
30969
22:13:40,144 --> 22:13:41,144
there are three types wet pipe dry pipe
30970
22:13:42,424 --> 22:13:43,424
and gas
30971
22:13:43,856 --> 22:13:44,856
the wet pipe is basically a water that's
30972
22:13:46,680 --> 22:13:47,680
held within the pipe under pressure and
30973
22:13:49,616 --> 22:13:50,616
it breaks a little seal which you can
30974
22:13:51,176 --> 22:13:52,176
see in the picture there the little red
30975
22:13:53,464 --> 22:13:54,464
seal and that um when that breaks it
30976
22:13:56,216 --> 22:13:57,216
lets the water come out
30977
22:13:58,256 --> 22:13:59,256
and obviously soaks everything with
30978
22:14:00,600 --> 22:14:01,600
water and that's the end of your
30979
22:14:02,160 --> 22:14:03,160
equipment
30980
22:14:03,656 --> 22:14:04,656
and it will bring your data center down
30981
22:14:05,824 --> 22:14:06,824
the drive pipe is the same as a wet pipe
30982
22:14:08,160 --> 22:14:09,160
but the water's not kept in the pipes
30983
22:14:10,616 --> 22:14:11,616
and the reason is it accumulates
30984
22:14:12,480 --> 22:14:13,480
moisture and if there's a drape it can
30985
22:14:15,056 --> 22:14:16,056
damage the equipment and obviously
30986
22:14:18,056 --> 22:14:19,056
um could cause rust
30987
22:14:20,216 --> 22:14:21,216
since the dry pipe is a water-based
30988
22:14:22,016 --> 22:14:23,016
system the disadvantage is the same as
30989
22:14:23,872 --> 22:14:24,872
the wet pipe
30990
22:14:25,080 --> 22:14:26,080
now you've got gas suppression
30991
22:14:26,696 --> 22:14:27,696
suppression which is the norm in your
30992
22:14:29,464 --> 22:14:30,464
data centers it basically starves the
30993
22:14:32,360 --> 22:14:33,360
fire of oxygen and the fires need oxygen
30994
22:14:36,176 --> 22:14:37,176
in order to generate the Heat
30995
22:14:39,120 --> 22:14:40,120
clean agents such as fm200 remove the
30996
22:14:41,696 --> 22:14:42,696
heat from the fire and here's some large
30997
22:14:43,920 --> 22:14:44,920
industrially scale heat agents
30998
22:14:47,696 --> 22:14:48,696
and inert gases such as carbon dioxide
30999
22:14:50,160 --> 22:14:51,160
deprive the fire of oxygen
31000
22:14:52,744 --> 22:14:53,744
you do get immediate recovery of
31001
22:14:54,600 --> 22:14:55,600
business operations you've obviously got
31002
22:14:56,216 --> 22:14:57,216
to vent the area before people are
31003
22:14:58,376 --> 22:14:59,376
allowed back in otherwise they'll just
31004
22:15:00,056 --> 22:15:01,056
pass out
31005
22:15:01,256 --> 22:15:02,256
and and you've got to have training for
31006
22:15:03,480 --> 22:15:04,480
the staff
31007
22:15:04,744 --> 22:15:05,744
it doesn't actually mention I didn't put
31008
22:15:06,536 --> 22:15:07,536
in here but you obviously need an
31009
22:15:08,280 --> 22:15:09,280
evacuation plan so that there's normally
31010
22:15:11,936 --> 22:15:12,936
a diagram in several key places and and
31011
22:15:14,696 --> 22:15:15,696
signed exits
31012
22:15:16,800 --> 22:15:17,800
as mentioned in the syllabus but I just
31013
22:15:18,832 --> 22:15:19,832
thought it was so obvious because we all
31014
22:15:20,400 --> 22:15:21,400
see them wherever we go even coffee
31015
22:15:22,376 --> 22:15:23,376
shops have got fire exits of fire escape
31016
22:15:25,016 --> 22:15:26,016
plans
31017
22:15:26,336 --> 22:15:27,336
lifting techniques well you can see this
31018
22:15:28,680 --> 22:15:29,680
guy here is bending his back not his
31019
22:15:31,144 --> 22:15:32,144
knees which isn't a recommended way to
31020
22:15:33,784 --> 22:15:34,784
do things
31021
22:15:35,040 --> 22:15:36,040
easiest way is to adjust houses through
31022
22:15:37,376 --> 22:15:38,376
improper lifting don't really lift the
31023
22:15:39,424 --> 22:15:40,424
equipment if it weighs more than a
31024
22:15:40,856 --> 22:15:41,856
quarter of your weight lift with your
31025
22:15:42,896 --> 22:15:43,896
legs with a straight back obviously if
31026
22:15:44,400 --> 22:15:45,400
you have injuries especially back
31027
22:15:46,144 --> 22:15:47,144
injuries then don't attempt it and a lot
31028
22:15:49,144 --> 22:15:50,144
of the time there's lifted equipments
31029
22:15:51,536 --> 22:15:52,536
there that will oyster for you or hold
31030
22:15:54,120 --> 22:15:55,120
it in place while you screw things or
31031
22:15:57,120 --> 22:15:58,120
unscrew them and Slot them in
31032
22:15:59,296 --> 22:16:00,296
anti-static static electricity as I
31033
22:16:01,744 --> 22:16:02,744
mentioned at the start will fry various
31034
22:16:03,960 --> 22:16:04,960
components and that's happened to me
31035
22:16:05,512 --> 22:16:06,512
when I've installed motherboards and
31036
22:16:07,856 --> 22:16:08,856
other devices I've just heard a Little
31037
22:16:09,656 --> 22:16:10,656
Fizz and some things
31038
22:16:11,824 --> 22:16:12,824
um something's broken so use anti-static
31039
22:16:14,760 --> 22:16:15,760
devices
31040
22:16:16,496 --> 22:16:17,496
there's anti-static bags and also wrist
31041
22:16:19,080 --> 22:16:20,080
straps that you can connect to your
31042
22:16:21,896 --> 22:16:22,896
wrist and then connect to an earth
31043
22:16:23,824 --> 22:16:24,824
somewhere that will prevent the
31044
22:16:26,400 --> 22:16:27,400
um
31045
22:16:27,120 --> 22:16:28,120
causing the spark somewhere because as
31046
22:16:29,512 --> 22:16:30,512
we walk around we're generating
31047
22:16:30,784 --> 22:16:31,784
electricity static electricity
31048
22:16:33,720 --> 22:16:34,720
stabilizing Iraq is important to have a
31049
22:16:35,872 --> 22:16:36,872
correctly stabilized rack with the um
31050
22:16:38,464 --> 22:16:39,464
fate which are all adjustable racks are
31051
22:16:41,464 --> 22:16:42,464
not stable or likely to collapse at any
31052
22:16:43,192 --> 22:16:44,192
time
31053
22:16:45,000 --> 22:16:46,000
um you put your large equipment in at
31054
22:16:46,744 --> 22:16:47,744
the bottom
31055
22:16:47,824 --> 22:16:48,824
and the lighter at the top there
31056
22:16:50,760 --> 22:16:51,760
and moving on to another syllabus item
31057
22:16:53,640 --> 22:16:54,640
is the MSDS the material safety data
31058
22:16:56,872 --> 22:16:57,872
sheet which you'll go into this is a
31059
22:16:59,696 --> 22:17:00,696
document that contains information about
31060
22:17:01,504 --> 22:17:02,504
hazardous chemicals
31061
22:17:03,360 --> 22:17:04,360
used as a primary means to communicate
31062
22:17:05,640 --> 22:17:06,640
and the chemical hazards to staff I
31063
22:17:08,824 --> 22:17:09,824
presume you'd go in some sort of
31064
22:17:10,016 --> 22:17:11,016
training course for for this not um
31065
22:17:13,256 --> 22:17:14,256
not just read something on a wall
31066
22:17:14,936 --> 22:17:15,936
preferred by the manufacturer or
31067
22:17:16,800 --> 22:17:17,800
supplier of the chemical
31068
22:17:19,376 --> 22:17:20,376
you have to make the MSDS available in
31069
22:17:21,960 --> 22:17:22,960
your workplace for each hazardous
31070
22:17:23,400 --> 22:17:24,400
chemical or a mixture of such hazardous
31071
22:17:26,040 --> 22:17:27,040
chemicals
31072
22:17:27,176 --> 22:17:28,176
it should be ready available to all
31073
22:17:28,920 --> 22:17:29,920
those who may come into contact with
31074
22:17:30,424 --> 22:17:31,424
such hazardous chemicals
31075
22:17:34,192 --> 22:17:35,192
the occupational safety and health
31076
22:17:36,424 --> 22:17:37,424
administration and I presume these are
31077
22:17:38,512 --> 22:17:39,512
American different countries will have
31078
22:17:39,960 --> 22:17:40,960
different organizations or
31079
22:17:41,936 --> 22:17:42,936
Administrations
31080
22:17:43,320 --> 22:17:44,320
they're part of the US Department of
31081
22:17:45,240 --> 22:17:46,240
Labor create the hazard communication
31082
22:17:47,872 --> 22:17:48,872
standard to ensure that all
31083
22:17:50,576 --> 22:17:51,576
um chemicals that are hazardous are
31084
22:17:52,016 --> 22:17:53,016
evaluated and the information is
31085
22:17:54,176 --> 22:17:55,176
correctly passed
31086
22:17:56,336 --> 22:17:57,336
should be in English this should be
31087
22:17:58,080 --> 22:17:59,080
include 12 items mandated which will go
31088
22:18:00,360 --> 22:18:01,360
through briefly
31089
22:18:01,744 --> 22:18:02,744
the name of the chemical the physically
31090
22:18:03,720 --> 22:18:04,720
chemical pop and properties such as
31091
22:18:06,360 --> 22:18:07,360
color and odor so you can recognize it
31092
22:18:08,696 --> 22:18:09,696
if it does have a color a lot of them
31093
22:18:10,680 --> 22:18:11,680
have odors added
31094
22:18:12,480 --> 22:18:13,480
such as their natural gas has an odor
31095
22:18:14,824 --> 22:18:15,824
added certainly did in the UK so you
31096
22:18:17,760 --> 22:18:18,760
could smell it if there was a leak and
31097
22:18:20,104 --> 22:18:21,104
before that and people didn't know that
31098
22:18:22,016 --> 22:18:23,016
the house was full of gas and uh lit a
31099
22:18:24,600 --> 22:18:25,600
cigarette and that was the end of them
31100
22:18:26,400 --> 22:18:27,400
physical hundreds uh hazards such as
31101
22:18:28,744 --> 22:18:29,744
explosiveness or could it react with
31102
22:18:30,784 --> 22:18:31,784
something
31103
22:18:32,576 --> 22:18:33,576
uh health hazards such as corrosive to
31104
22:18:34,800 --> 22:18:35,800
eyes or skin you normally have that in a
31105
22:18:37,016 --> 22:18:38,016
diagram as well
31106
22:18:38,336 --> 22:18:39,336
primary ways you can enter your body
31107
22:18:40,192 --> 22:18:41,192
such as always breathing
31108
22:18:43,376 --> 22:18:44,376
allowable limits of exposure before you
31109
22:18:46,192 --> 22:18:47,192
get seriously injured or die
31110
22:18:49,144 --> 22:18:50,144
carcinogen
31111
22:18:54,720 --> 22:18:55,720
precautions before you use it masks or
31112
22:18:57,896 --> 22:18:58,896
goggles special equipment
31113
22:19:00,832 --> 22:19:01,832
and do you need any gloves
31114
22:19:03,056 --> 22:19:04,056
protection
31115
22:19:05,696 --> 22:19:06,696
and Engineering controls
31116
22:19:09,176 --> 22:19:10,176
first aid if it all goes wrong normally
31117
22:19:11,640 --> 22:19:12,640
as the number of the Emergency Services
31118
22:19:13,576 --> 22:19:14,576
the date when it was prepared the
31119
22:19:16,496 --> 22:19:17,496
document and the last revision
31120
22:19:19,440 --> 22:19:20,440
contact details of the person who's
31121
22:19:21,720 --> 22:19:22,720
responsible
31122
22:19:24,144 --> 22:19:25,144
all right we've covered a lot here and
31123
22:19:26,464 --> 22:19:27,464
it's all your health and safety stuff
31124
22:19:27,896 --> 22:19:28,896
your data center your HVAC
31125
22:19:30,720 --> 22:19:31,720
hot and cold aisles and a correct
31126
22:19:33,176 --> 22:19:34,176
loading of your racks
31127
22:19:36,000 --> 22:19:37,000
fire risk fire suppression and the
31128
22:19:38,760 --> 22:19:39,760
impact your type of Agents
31129
22:19:41,936 --> 22:19:42,936
lifting without injuring yourself or
31130
22:19:44,280 --> 22:19:45,280
others
31131
22:19:45,360 --> 22:19:46,360
you're anti-static and rack
31132
22:19:47,040 --> 22:19:48,040
stabilization and your MSDS so that's
31133
22:19:50,640 --> 22:19:51,640
all thanks for watching
31134
22:19:55,530 --> 22:19:56,530
[Music]
31135
22:20:03,296 --> 22:20:04,296
foreign
31136
22:20:12,800 --> 22:20:13,800
lesson one common wireless issues
31137
22:20:17,400 --> 22:20:18,400
and we look at signal loss interference
31138
22:20:19,552 --> 22:20:20,552
signal to noise device saturation
31139
22:20:22,104 --> 22:20:23,104
bandwidth saturation
31140
22:20:24,784 --> 22:20:25,784
untested updates getting your SSID wrong
31141
22:20:28,856 --> 22:20:29,856
so you can guess how to fix that one
31142
22:20:31,256 --> 22:20:32,256
power levels open networks Rogue access
31143
22:20:34,376 --> 22:20:35,376
points
31144
22:20:36,424 --> 22:20:37,424
wrong antenna for your device
31145
22:20:39,552 --> 22:20:40,552
incompatibilities wrong encryption and
31146
22:20:43,016 --> 22:20:44,016
bounce most of these are pretty Common
31147
22:20:46,256 --> 22:20:47,256
Sense actually but I've put these in
31148
22:20:49,016 --> 22:20:50,016
because
31149
22:20:49,976 --> 22:20:50,976
um it's on the syllabus and if you've
31150
22:20:52,256 --> 22:20:53,256
got a home wireless device or even
31151
22:20:55,256 --> 22:20:56,256
you've used Wireless on your mobile
31152
22:20:57,960 --> 22:20:58,960
phone you probably have to troubleshoot
31153
22:21:00,176 --> 22:21:01,176
most of these issues
31154
22:21:02,336 --> 22:21:03,336
um but we'll cover them nonetheless just
31155
22:21:04,192 --> 22:21:05,192
in case signal loss you've got no signal
31156
22:21:07,144 --> 22:21:08,144
or low signal
31157
22:21:08,824 --> 22:21:09,824
there's connectivity and there's no
31158
22:21:11,872 --> 22:21:12,872
connectivity when there's no signal
31159
22:21:14,464 --> 22:21:15,464
there's latency and inconsistent
31160
22:21:16,192 --> 22:21:17,192
connectivity when the signal strength is
31161
22:21:18,240 --> 22:21:19,240
low
31162
22:21:20,696 --> 22:21:21,696
client devices closer to the access
31163
22:21:23,040 --> 22:21:24,040
point especially when you're at home
31164
22:21:24,536 --> 22:21:25,536
actually
31165
22:21:26,104 --> 22:21:27,104
if you've got a your wireless access
31166
22:21:28,496 --> 22:21:29,496
point in a different room and if you've
31167
22:21:32,400 --> 22:21:33,400
got an older house certainly in the UK
31168
22:21:34,256 --> 22:21:35,256
most of the walls were made of
31169
22:21:36,656 --> 22:21:37,656
um thick concrete
31170
22:21:39,656 --> 22:21:40,656
and uh they built the houses to last
31171
22:21:42,600 --> 22:21:43,600
there was no or very few false walls
31172
22:21:45,832 --> 22:21:46,832
inside houses with just plasterboard or
31173
22:21:47,936 --> 22:21:48,936
wood
31174
22:21:49,856 --> 22:21:50,856
um obviously you can install
31175
22:21:51,784 --> 22:21:52,784
um a booster as well you can install
31176
22:21:53,640 --> 22:21:54,640
something in your power unit and it will
31177
22:21:57,536 --> 22:21:58,536
boost the signal or act as a repeater
31178
22:22:00,896 --> 22:22:01,896
ensure there's minimal obstructions
31179
22:22:03,056 --> 22:22:04,056
metal studs is another one that will
31180
22:22:05,512 --> 22:22:06,512
reduce your um
31181
22:22:08,280 --> 22:22:09,280
connectivity or signal ensure the
31182
22:22:11,040 --> 22:22:12,040
antennas allow communication as well
31183
22:22:12,832 --> 22:22:13,832
sometimes the antennas come in a box
31184
22:22:16,144 --> 22:22:17,144
or um they're not attached or they're
31185
22:22:19,080 --> 22:22:20,080
just pointed in the wrong direction
31186
22:22:22,280 --> 22:22:23,280
interference other wireless devices are
31187
22:22:24,960 --> 22:22:25,960
using the same frequency uh you can also
31188
22:22:27,536 --> 22:22:28,536
have interference from microwave ovens
31189
22:22:29,400 --> 22:22:30,400
and cordless phones it tells you this in
31190
22:22:31,856 --> 22:22:32,856
the documentation but most people don't
31191
22:22:33,720 --> 22:22:34,720
read it when you're installing your
31192
22:22:36,480 --> 22:22:37,480
wireless router it'll have a pictures of
31193
22:22:38,824 --> 22:22:39,824
the kind of things that will interfere
31194
22:22:40,696 --> 22:22:41,696
with your signal
31195
22:22:42,784 --> 22:22:43,784
you'll get latency and inconsistent
31196
22:22:45,832 --> 22:22:46,832
connectivity avoid interference pretty
31197
22:22:49,016 --> 22:22:50,016
obvious as I said and but you can avoid
31198
22:22:52,552 --> 22:22:53,552
having your devices near to these things
31199
22:22:54,424 --> 22:22:55,424
like your ovens or cordless phones
31200
22:22:57,960 --> 22:22:58,960
um you may be able to change your
31201
22:22:59,280 --> 22:23:00,280
channel as well if it's got the same
31202
22:23:00,656 --> 22:23:01,656
channel as your cordless phone uses
31203
22:23:03,552 --> 22:23:04,552
overlapping channels because of the
31204
22:23:05,696 --> 22:23:06,696
wireless access points are used in the
31205
22:23:07,680 --> 22:23:08,680
same frequency there's automatic channel
31206
22:23:09,896 --> 22:23:10,896
selection normally on your devices but
31207
22:23:12,720 --> 22:23:13,720
if you have any
31208
22:23:14,160 --> 22:23:15,160
reasonable amount of ability you should
31209
22:23:16,080 --> 22:23:17,080
be able to log in and change your
31210
22:23:17,696 --> 22:23:18,696
channels
31211
22:23:20,400 --> 22:23:21,400
uh avoid uh you can correct it by
31212
22:23:23,336 --> 22:23:24,336
avoiding the manual selection of
31213
22:23:24,920 --> 22:23:25,920
non-overlapping channels
31214
22:23:27,296 --> 22:23:28,296
signal to noise ratio it's the ratio of
31215
22:23:30,000 --> 22:23:31,000
the Wi-Fi signal to the outside
31216
22:23:31,256 --> 22:23:32,256
interference or noise noise is in
31217
22:23:34,080 --> 22:23:35,080
respect of Wireless have a negative
31218
22:23:36,424 --> 22:23:37,424
impact on your wireless signal other
31219
22:23:38,760 --> 22:23:39,760
Wi-Fi signals don't count as noise
31220
22:23:41,824 --> 22:23:42,824
this again will give you connectivity
31221
22:23:43,856 --> 22:23:44,856
issues or latency
31222
22:23:46,496 --> 22:23:47,496
signal levels and noise levels can be
31223
22:23:49,256 --> 22:23:50,256
visualized as heat Maps
31224
22:23:51,480 --> 22:23:52,480
the ratio of 10 to 15 decibels is
31225
22:23:53,696 --> 22:23:54,696
considered unreliable
31226
22:23:57,240 --> 22:23:58,240
16 to 24 is weak
31227
22:23:59,824 --> 22:24:00,824
issues can be avoided by increasing your
31228
22:24:02,160 --> 22:24:03,160
signal strength and decreasing the noise
31229
22:24:04,744 --> 22:24:05,744
I told you all this stuff was obvious
31230
22:24:06,056 --> 22:24:07,056
device saturation is when more wireless
31231
22:24:08,640 --> 22:24:09,640
devices are connected to your network
31232
22:24:10,280 --> 22:24:11,280
you'll get a decrease throughput that's
31233
22:24:13,256 --> 22:24:14,256
probably your fault for letting your
31234
22:24:14,512 --> 22:24:15,512
kids have access to phones at home or
31235
22:24:17,104 --> 22:24:18,104
other wireless devices bandwidth
31236
22:24:20,336 --> 22:24:21,336
saturation is when one or more devices
31237
22:24:22,320 --> 22:24:23,320
transmit a large quality of quantity of
31238
22:24:24,536 --> 22:24:25,536
data
31239
22:24:26,512 --> 22:24:27,512
um I would imagine received also so if
31240
22:24:28,376 --> 22:24:29,376
somebody in is there watching YouTube in
31241
22:24:31,080 --> 22:24:32,080
another
31242
22:24:31,920 --> 22:24:32,920
room in the house and that'll do it
31243
22:24:35,216 --> 22:24:36,216
untested updates
31244
22:24:37,016 --> 22:24:38,016
um updates can obviously break things if
31245
22:24:39,056 --> 22:24:40,056
they haven't been uh correctly tested
31246
22:24:41,160 --> 22:24:42,160
especially with regards firmware I've
31247
22:24:44,464 --> 22:24:45,464
even recently installed a an SSD drive
31248
22:24:47,872 --> 22:24:48,872
in my
31249
22:24:49,016 --> 22:24:50,016
home computer and while I was just
31250
22:24:51,960 --> 22:24:52,960
researching it I found that the latest
31251
22:24:54,120 --> 22:24:55,120
firmware drive from the manufacturer
31252
22:24:56,176 --> 22:24:57,176
actually was wiping everyone's data
31253
22:24:59,280 --> 22:25:00,280
which is catastrophic for most of us and
31254
22:25:02,336 --> 22:25:03,336
the manufacturer was aware and they said
31255
22:25:04,080 --> 22:25:05,080
they were releasing an update but the
31256
22:25:06,056 --> 22:25:07,056
problem is if you downloaded the update
31257
22:25:07,976 --> 22:25:08,976
it was too late for you
31258
22:25:11,040 --> 22:25:12,040
back up your last working config not
31259
22:25:13,616 --> 22:25:14,616
sure how you do that with your firmware
31260
22:25:15,056 --> 22:25:16,056
actually but you can research that
31261
22:25:16,800 --> 22:25:17,800
yourself wrong SSID all you need to do
31262
22:25:20,640 --> 22:25:21,640
because they're case sensitive you could
31263
22:25:22,552 --> 22:25:23,552
have the wrong case or just mistype
31264
22:25:24,784 --> 22:25:25,784
something
31265
22:25:26,216 --> 22:25:27,216
a lot of the time when you type these
31266
22:25:27,656 --> 22:25:28,656
out you can't actually see the letters
31267
22:25:29,160 --> 22:25:30,160
you're typing unless there's a an option
31268
22:25:31,376 --> 22:25:32,376
for you to do that so you could well
31269
22:25:33,360 --> 22:25:34,360
have typed out the incorrect password
31270
22:25:34,552 --> 22:25:35,552
but you can't see it
31271
22:25:37,504 --> 22:25:38,504
avoid having the client device and the
31272
22:25:39,424 --> 22:25:40,424
access point set to use the same SSID
31273
22:25:44,104 --> 22:25:45,104
power levels uh users will experience a
31274
22:25:46,744 --> 22:25:47,744
big coverage area or small
31275
22:25:48,856 --> 22:25:49,856
coverage area because of low power
31276
22:25:51,056 --> 22:25:52,056
levels and access points big coverage
31277
22:25:53,760 --> 22:25:54,760
areas occur because of high power levels
31278
22:25:56,576 --> 22:25:57,576
and access points
31279
22:25:58,144 --> 22:25:59,144
and avoid it by adjusting the power
31280
22:26:00,176 --> 22:26:01,176
levels for a good coverage area
31281
22:26:03,720 --> 22:26:04,720
open network is an unsecured wireless
31282
22:26:05,696 --> 22:26:06,696
network you used to see a lot of those
31283
22:26:07,376 --> 22:26:08,376
around but most people now have become
31284
22:26:09,720 --> 22:26:10,720
Savvy or the default settings on the
31285
22:26:13,080 --> 22:26:14,080
home routers I've got security chosen
31286
22:26:16,744 --> 22:26:17,744
automatically
31287
22:26:18,296 --> 22:26:19,296
unauthorized devices May connect to the
31288
22:26:20,464 --> 22:26:21,464
network if it's insecure so obviously
31289
22:26:22,976 --> 22:26:23,976
change the security settings if this is
31290
22:26:24,896 --> 22:26:25,896
the case
31291
22:26:25,856 --> 22:26:26,856
Rogue access points as an authorized
31292
22:26:29,160 --> 22:26:30,160
access point installed on the network
31293
22:26:30,920 --> 22:26:31,920
normally employees uh just for a bit of
31294
22:26:34,144 --> 22:26:35,144
convenience will go into their desk and
31295
22:26:36,424 --> 22:26:37,424
plug something in to get wireless access
31296
22:26:38,960 --> 22:26:39,960
malicious attacker can install Rogue
31297
22:26:41,400 --> 22:26:42,400
access points uh thus getting them
31298
22:26:43,976 --> 22:26:44,976
access to the network
31299
22:26:46,856 --> 22:26:47,856
wrong antenna type signal coverage
31300
22:26:49,320 --> 22:26:50,320
depends on your type of antenna so you
31301
22:26:51,656 --> 22:26:52,656
could have no signal or poor signal or
31302
22:26:55,920 --> 22:26:56,920
um a good signal but far away from the
31303
22:26:58,144 --> 22:26:59,144
access point
31304
22:27:00,832 --> 22:27:01,832
okay
31305
22:27:01,872 --> 22:27:02,872
omnidirectional and directional are two
31306
22:27:04,144 --> 22:27:05,144
main types of antenna omnidirectional
31307
22:27:06,600 --> 22:27:07,600
gives you 360 degree degree patterns
31308
22:27:11,960 --> 22:27:12,960
suitable for inside an office conference
31309
22:27:15,240 --> 22:27:16,240
area
31310
22:27:16,680 --> 22:27:17,680
directional will give you a signal in a
31311
22:27:18,960 --> 22:27:19,960
particular direction so your coverage is
31312
22:27:21,784 --> 22:27:22,784
limited to that One Direction
31313
22:27:25,440 --> 22:27:26,440
you got a yagi
31314
22:27:27,856 --> 22:27:28,856
parabolic grid patch and panel antennas
31315
22:27:33,000 --> 22:27:34,000
the jaegi and parabolic grid are used to
31316
22:27:36,896 --> 22:27:37,896
connect one building to another you must
31317
22:27:38,936 --> 22:27:39,936
have line of sight so if somebody's got
31318
22:27:41,512 --> 22:27:42,512
a tree there or something else temporary
31319
22:27:44,040 --> 22:27:45,040
or permanent then it's going to cause
31320
22:27:45,480 --> 22:27:46,480
you issues that you'll have to
31321
22:27:48,120 --> 22:27:49,120
troubleshoot
31322
22:27:49,552 --> 22:27:50,552
and if you see if there's
31323
22:27:50,824 --> 22:27:51,824
incompatibilities users may not be able
31324
22:27:52,920 --> 22:27:53,920
to get access to the WAP the settings
31325
22:27:55,320 --> 22:27:56,320
may be incompatible standard supporting
31326
22:27:58,552 --> 22:27:59,552
if you've got a very old
31327
22:28:01,144 --> 22:28:02,144
um Wireless car that you've got on your
31328
22:28:03,120 --> 22:28:04,120
device a PCI card or USB it might not be
31329
22:28:06,656 --> 22:28:07,656
compatible with your other device
31330
22:28:09,656 --> 22:28:10,656
so 802.11a is not compatible with 11b
31331
22:28:13,320 --> 22:28:14,320
and 11g
31332
22:28:15,896 --> 22:28:16,896
you've got to look at what is compatible
31333
22:28:17,576 --> 22:28:18,576
so B is compatible with G and vice versa
31334
22:28:20,216 --> 22:28:21,216
some are backward compatibility
31335
22:28:22,760 --> 22:28:23,760
compatible others aren't
31336
22:28:26,464 --> 22:28:27,464
uh wrong encryption you may not be uh
31337
22:28:29,216 --> 22:28:30,216
get a connection with the wireless
31338
22:28:30,960 --> 22:28:31,960
access points
31339
22:28:32,872 --> 22:28:33,872
the client device and wireless access
31340
22:28:34,440 --> 22:28:35,440
may have different encryption settings
31341
22:28:36,000 --> 22:28:37,000
so you need to check that
31342
22:28:38,760 --> 22:28:39,760
um what's configured on your access
31343
22:28:40,256 --> 22:28:41,256
point is matching on your wireless card
31344
22:28:43,744 --> 22:28:44,744
or wireless device whatever you're using
31345
22:28:46,192 --> 22:28:47,192
so do configure it correctly examples
31346
22:28:48,784 --> 22:28:49,784
are web WPA and WPA2
31347
22:28:52,800 --> 22:28:53,800
bounce is when your signal bounces off
31348
22:28:54,784 --> 22:28:55,784
an obstacle without reaching the
31349
22:28:57,000 --> 22:28:58,000
destination you can get weak or no
31350
22:28:59,464 --> 22:29:00,464
connectivity you need to remove the
31351
22:29:01,440 --> 22:29:02,440
obstacle obviously sometimes that's
31352
22:29:03,424 --> 22:29:04,424
easier said than done so if it's a big
31353
22:29:05,280 --> 22:29:06,280
thick concrete wall in your house don't
31354
22:29:07,016 --> 22:29:08,016
don't knock it down because your roof
31355
22:29:08,936 --> 22:29:09,936
will fall down you need to either get
31356
22:29:10,920 --> 22:29:11,920
some sort of booster
31357
22:29:12,600 --> 22:29:13,600
or um move where you're connecting from
31358
22:29:15,600 --> 22:29:16,600
or just find a alternative connection
31359
22:29:17,512 --> 22:29:18,512
type
31360
22:29:18,784 --> 22:29:19,784
such as connecting through the um
31361
22:29:21,120 --> 22:29:22,120
ethernet devices that were plugged into
31362
22:29:23,040 --> 22:29:24,040
your power
31363
22:29:24,296 --> 22:29:25,296
all right so we've covered a lot a
31364
22:29:26,216 --> 22:29:27,216
signal loss interference signal to noise
31365
22:29:29,360 --> 22:29:30,360
saturation bandwidth saturation
31366
22:29:33,056 --> 22:29:34,056
untested updates wrong SSID and your
31367
22:29:36,896 --> 22:29:37,896
power
31368
22:29:37,800 --> 22:29:38,800
open networks Rogue access points
31369
22:29:41,824 --> 22:29:42,824
the wrong antenna type incompatibilities
31370
22:29:44,536 --> 22:29:45,536
are on encryption and bounce that's all
31371
22:29:48,424 --> 22:29:49,424
for now thanks for watching
31372
22:29:53,100 --> 22:29:54,100
[Music]
31373
22:30:01,512 --> 22:30:02,512
thank you
31374
22:30:09,000 --> 22:30:10,000
welcome to module 19 lesson 2 Common
31375
22:30:11,824 --> 22:30:12,824
copper cable issues that's a mouthful
31376
22:30:15,360 --> 22:30:16,360
so some of the common issues you'll
31377
22:30:17,336 --> 22:30:18,336
experience as a network engineer
31378
22:30:20,040 --> 22:30:21,040
our shorts opens incorrect termination
31379
22:30:23,240 --> 22:30:24,240
crosstalk
31380
22:30:24,744 --> 22:30:25,744
Emi distance limitations attenuation the
31381
22:30:29,280 --> 22:30:30,280
cable issues
31382
22:30:31,504 --> 22:30:32,504
shorts is basically short for a short
31383
22:30:34,192 --> 22:30:35,192
circuit it allows the current to travel
31384
22:30:36,296 --> 22:30:37,296
in a path that wasn't intended and the
31385
22:30:39,784 --> 22:30:40,784
cable wasn't designed for a couple was
31386
22:30:42,600 --> 22:30:43,600
in the cables are insulated so they
31387
22:30:44,760 --> 22:30:45,760
don't come into contact with each other
31388
22:30:46,192 --> 22:30:47,192
if
31389
22:30:47,760 --> 22:30:48,760
um there's some sort of issue a lot of
31390
22:30:49,256 --> 22:30:50,256
the time it's because it's frayed
31391
22:30:50,512 --> 22:30:51,512
somebody's bent the cable around a Bend
31392
22:30:53,216 --> 22:30:54,216
or just done something with it or folded
31393
22:30:55,856 --> 22:30:56,856
it too many times and unfolded it then
31394
22:30:58,192 --> 22:30:59,192
the cables can touch each other and then
31395
22:31:00,424 --> 22:31:01,424
you've got a short circuit you depended
31396
22:31:03,360 --> 22:31:04,360
on how bad it is you'll have
31397
22:31:04,552 --> 22:31:05,552
intermittent connectivity issues you
31398
22:31:07,320 --> 22:31:08,320
could use a TDR that will locate the
31399
22:31:09,656 --> 22:31:10,656
short in the cable this is one of your
31400
22:31:12,656 --> 22:31:13,656
troubleshooting tools that you could use
31401
22:31:16,496 --> 22:31:17,496
an open refers to an incomplete
31402
22:31:18,360 --> 22:31:19,360
electrical circuit in which there's no
31403
22:31:20,040 --> 22:31:21,040
current if one of the copper wires
31404
22:31:22,616 --> 22:31:23,616
inside the cable is cut or just broken
31405
22:31:24,720 --> 22:31:25,720
for some reason then you've got an open
31406
22:31:27,296 --> 22:31:28,296
circuit you would normally then have no
31407
22:31:29,696 --> 22:31:30,696
connectivity
31408
22:31:31,440 --> 22:31:32,440
again you can use a TDR that can be used
31409
22:31:34,440 --> 22:31:35,440
to locate openings in the cable
31410
22:31:37,192 --> 22:31:38,192
incorrect termination generally happens
31411
22:31:39,960 --> 22:31:40,960
when you've made your own cables or your
31412
22:31:42,720 --> 22:31:43,720
cable engineer has done it and just made
31413
22:31:45,296 --> 22:31:46,296
a mistake or done it too quickly or just
31414
22:31:47,280 --> 22:31:48,280
not
31415
22:31:48,056 --> 22:31:49,056
and been watching what they're doing and
31416
22:31:50,104 --> 22:31:51,104
it's obviously human error then don't
31417
22:31:52,080 --> 22:31:53,080
happen it doesn't happen as much in um
31418
22:31:54,360 --> 22:31:55,360
professionally made cables so you
31419
22:31:56,824 --> 22:31:57,824
haven't properly terminated as per the
31420
22:31:59,040 --> 22:32:00,040
standards you could have got the wires
31421
22:32:00,240 --> 22:32:01,240
mixed up or not squash the um the RJ45
31422
22:32:05,040 --> 22:32:06,040
connector onto the wires correctly and
31423
22:32:07,744 --> 22:32:08,744
it's a bit of an art to it so you could
31424
22:32:09,784 --> 22:32:10,784
have no connection or intermittent
31425
22:32:11,936 --> 22:32:12,936
connection issues
31426
22:32:15,296 --> 22:32:16,296
straight through cables should be
31427
22:32:16,856 --> 22:32:17,856
terminated either using
31428
22:32:20,000 --> 22:32:21,000
t568 a or b
31429
22:32:23,280 --> 22:32:24,280
crossover cable has got a on one end and
31430
22:32:25,976 --> 22:32:26,976
B on the other so pins one goes to three
31431
22:32:28,744 --> 22:32:29,744
and two goes to six on the other end
31432
22:32:31,744 --> 22:32:32,744
use the cable tester to check if your
31433
22:32:34,256 --> 22:32:35,256
Cable's properly terminated and what
31434
22:32:36,656 --> 22:32:37,656
type it is
31435
22:32:37,856 --> 22:32:38,856
crosstalk is when the signal from The
31436
22:32:39,720 --> 22:32:40,720
Wire interferes with the signal on
31437
22:32:41,216 --> 22:32:42,216
another wire
31438
22:32:42,360 --> 22:32:43,360
less of an issue now with modern
31439
22:32:45,120 --> 22:32:46,120
um shielded twisted pair
31440
22:32:47,464 --> 22:32:48,464
uh cables
31441
22:32:50,336 --> 22:32:51,336
you measure with the cable tester or TDR
31442
22:32:53,512 --> 22:32:54,512
again the issues avoided if you buy a
31443
22:32:56,216 --> 22:32:57,216
professional cable basically because it
31444
22:32:57,896 --> 22:32:58,896
will be twisted properly
31445
22:32:59,824 --> 22:33:00,824
two types of crosstalk that you may be
31446
22:33:02,336 --> 22:33:03,336
asked about in the exam near end and far
31447
22:33:04,976 --> 22:33:05,976
end
31448
22:33:06,120 --> 22:33:07,120
and near end is refers to the crosstalk
31449
22:33:08,400 --> 22:33:09,400
that occurs at the terminated end of the
31450
22:33:10,320 --> 22:33:11,320
cable where the crosstalk has been
31451
22:33:12,240 --> 22:33:13,240
measured so this is where you're doing
31452
22:33:14,040 --> 22:33:15,040
the measuring
31453
22:33:15,784 --> 22:33:16,784
occurs near the connectors terminating
31454
22:33:17,760 --> 22:33:18,760
the cable far end is
31455
22:33:20,872 --> 22:33:21,872
um on the far end of the cable from
31456
22:33:22,976 --> 22:33:23,976
where you're doing the measurements
31457
22:33:25,016 --> 22:33:26,016
occurs near the connectors terminating
31458
22:33:27,120 --> 22:33:28,120
the far end of the cable
31459
22:33:29,656 --> 22:33:30,656
electromagnetic efference is normally
31460
22:33:31,744 --> 22:33:32,744
when you've laid the cable yourself and
31461
22:33:34,616 --> 22:33:35,616
it's gone
31462
22:33:35,872 --> 22:33:36,872
through or near some device that emits a
31463
22:33:39,240 --> 22:33:40,240
strong error signal
31464
22:33:42,000 --> 22:33:43,000
an emo signal also called radio
31465
22:33:45,056 --> 22:33:46,056
frequency interference
31466
22:33:47,216 --> 22:33:48,216
generate generated
31467
22:33:49,616 --> 22:33:50,616
um
31468
22:33:50,512 --> 22:33:51,512
by fluorescent lights electric motors
31469
22:33:53,696 --> 22:33:54,696
dynamos things like that so it could
31470
22:33:56,104 --> 22:33:57,104
happen in a workshop or when you haven't
31471
22:33:59,056 --> 22:34:00,056
properly housed your cable or it's not
31472
22:34:01,856 --> 22:34:02,856
running under the floor and you're
31473
22:34:03,480 --> 22:34:04,480
running it through the ceiling and it's
31474
22:34:04,800 --> 22:34:05,800
going through the
31475
22:34:06,600 --> 22:34:07,600
um
31476
22:34:07,640 --> 22:34:08,640
fluorescent lights
31477
22:34:11,640 --> 22:34:12,640
data transmission of copper cables is um
31478
22:34:14,280 --> 22:34:15,280
obviously disrupted when it's exposed
31479
22:34:16,552 --> 22:34:17,552
and it could be intermittent it could be
31480
22:34:18,536 --> 22:34:19,536
fine during the day and then later on in
31481
22:34:20,824 --> 22:34:21,824
the evening when somebody starts turning
31482
22:34:22,376 --> 22:34:23,376
the lights on it could be affected
31483
22:34:25,800 --> 22:34:26,800
avoid if you separate the power source
31484
22:34:27,720 --> 22:34:28,720
from the cables or by using shielded
31485
22:34:29,696 --> 22:34:30,696
cabling
31486
22:34:30,784 --> 22:34:31,784
you may have to buy a special type of
31487
22:34:32,576 --> 22:34:33,576
cabling if you're running your cables
31488
22:34:34,744 --> 22:34:35,744
through devices with a lot of very
31489
22:34:36,240 --> 22:34:37,240
powerful
31490
22:34:37,744 --> 22:34:38,744
um electrical signals
31491
22:34:40,016 --> 22:34:41,016
obviously there's distance limitations
31492
22:34:42,000 --> 22:34:43,000
per cable lost the signal when it
31493
22:34:44,824 --> 22:34:45,824
travels over a long distance you could
31494
22:34:46,496 --> 22:34:47,496
then have connectivity issues so if
31495
22:34:48,480 --> 22:34:49,480
you're running your cable over
31496
22:34:50,296 --> 22:34:51,296
120 meters when it's recommended 110
31497
22:34:53,400 --> 22:34:54,400
then you may well have issues
31498
22:34:57,600 --> 22:34:58,600
attenuation or DB loss refers to a loss
31499
22:35:00,656 --> 22:35:01,656
of signal strength the signal strength
31500
22:35:02,760 --> 22:35:03,760
is measured in decibels
31501
22:35:04,856 --> 22:35:05,856
uses experience degradation in network
31502
22:35:07,192 --> 22:35:08,192
performance you can avoid it by
31503
22:35:10,496 --> 22:35:11,496
um using cable runs within the maximum
31504
22:35:13,080 --> 22:35:14,080
supported distance using a signal
31505
22:35:15,656 --> 22:35:16,656
booster you probably need specialized
31506
22:35:17,872 --> 22:35:18,872
advice for this to be honest if you're
31507
22:35:19,744 --> 22:35:20,744
installing in a commercial premises
31508
22:35:22,256 --> 22:35:23,256
remove broken or damaged cables
31509
22:35:25,856 --> 22:35:26,856
and miscellaneous of the problems uh
31510
22:35:28,680 --> 22:35:29,680
verify the cables are present and
31511
22:35:30,424 --> 22:35:31,424
plugged in yes I've been asked to
31512
22:35:32,400 --> 22:35:33,400
troubleshoot devices when somebody
31513
22:35:35,000 --> 22:35:36,000
hasn't actually put the cable in yet it
31514
22:35:37,856 --> 22:35:38,856
hasn't been installed at all or
31515
22:35:40,256 --> 22:35:41,256
somebody's removed the cable for some
31516
22:35:41,936 --> 22:35:42,936
reason because they want to use it
31517
22:35:43,080 --> 22:35:44,080
somewhere else and not realized that
31518
22:35:45,480 --> 22:35:46,480
that is connecting to an end user or a
31519
22:35:48,176 --> 22:35:49,176
server
31520
22:35:49,080 --> 22:35:50,080
or some of the device
31521
22:35:50,936 --> 22:35:51,936
make sure the network adapter is enabled
31522
22:35:53,040 --> 22:35:54,040
and it has a valid addressing sometimes
31523
22:35:55,512 --> 22:35:56,512
devices have been up for years
31524
22:35:59,160 --> 22:36:00,160
and
31525
22:36:00,832 --> 22:36:01,832
um millions of packets have been passed
31526
22:36:03,360 --> 22:36:04,360
in in and out and it just needs
31527
22:36:05,824 --> 22:36:06,824
resetting or rebooting or the address
31528
22:36:08,216 --> 22:36:09,216
needs and refreshing on it it just
31529
22:36:11,160 --> 22:36:12,160
happens sometimes every period of time
31530
22:36:14,104 --> 22:36:15,104
make sure disabled ports are enabled for
31531
22:36:16,376 --> 22:36:17,376
connectivity sometimes ports are
31532
22:36:18,120 --> 22:36:19,120
disabled for security and you could plug
31533
22:36:20,872 --> 22:36:21,872
in a new user into a certain port on a
31534
22:36:24,424 --> 22:36:25,424
switch for example but that Port has
31535
22:36:26,400 --> 22:36:27,400
been disabled
31536
22:36:28,920 --> 22:36:29,920
you can have bad cables again sometimes
31537
22:36:31,552 --> 22:36:32,552
we bend them or just over time for
31538
22:36:34,376 --> 22:36:35,376
whatever reason the cable goes bad
31539
22:36:38,464 --> 22:36:39,464
misconfigured switch Port it could be
31540
22:36:40,496 --> 22:36:41,496
the wrong
31541
22:36:41,696 --> 22:36:42,696
um duplex setting or speed setting or
31542
22:36:43,856 --> 22:36:44,856
something else on there and it may not
31543
22:36:46,440 --> 22:36:47,440
work
31544
22:36:47,424 --> 22:36:48,424
misconfigured network card or a network
31545
22:36:50,512 --> 22:36:51,512
card that's failing or failed
31546
22:36:52,976 --> 22:36:53,976
software drivers I've mentioned
31547
22:36:54,600 --> 22:36:55,600
elsewhere that can cause huge problems
31548
22:36:57,000 --> 22:36:58,000
and it's not a problem you can actually
31549
22:36:58,872 --> 22:36:59,872
easily see until you start doing a bit
31550
22:37:01,256 --> 22:37:02,256
more research
31551
22:37:04,080 --> 22:37:05,080
all right so we've covered shorts opens
31552
22:37:06,480 --> 22:37:07,480
termination crosstalk Emi distance
31553
22:37:10,496 --> 22:37:11,496
attenuation and other problems
31554
22:37:13,320 --> 22:37:14,320
that's all for now thanks for watching
31555
22:37:20,070 --> 22:37:21,070
[Music]
31556
22:37:36,056 --> 22:37:37,056
welcome to module 19 lesson 3 common
31557
22:37:38,872 --> 22:37:39,872
fiber cable issues
31558
22:37:42,896 --> 22:37:43,896
so look it's troubleshooting uh
31559
22:37:45,360 --> 22:37:46,360
supported distances categories of
31560
22:37:47,464 --> 22:37:48,464
multi-mode fiber the bend radius
31561
22:37:51,120 --> 22:37:52,120
dirty connectors I think you can guess
31562
22:37:53,216 --> 22:37:54,216
what that one's about attenuation a
31563
22:37:56,696 --> 22:37:57,696
wavelength mismatch fiber type mismatch
31564
22:38:00,240 --> 22:38:01,240
so the bottom line with fiber cables is
31565
22:38:03,720 --> 22:38:04,720
uh if it's faulty it can't transport
31566
22:38:06,120 --> 22:38:07,120
data it tends to be either a working or
31567
22:38:09,176 --> 22:38:10,176
not working situation whereas with
31568
22:38:11,104 --> 22:38:12,104
copper you may well have a period of
31569
22:38:13,744 --> 22:38:14,744
time where the the performance just
31570
22:38:15,720 --> 22:38:16,720
deteriorates when you get in packet loss
31571
22:38:18,720 --> 22:38:19,720
or intermittent um connectivity and you
31572
22:38:22,320 --> 22:38:23,320
normally easily troubleshoot that by
31573
22:38:24,000 --> 22:38:25,000
just swapping the cable out if it all
31574
22:38:26,160 --> 22:38:27,160
works then it points to the fact that
31575
22:38:27,656 --> 22:38:28,656
the cable was faulty and they're so
31576
22:38:29,640 --> 22:38:30,640
cheap you just throw them away
31577
22:38:31,744 --> 22:38:32,744
obviously um fiber cables are not so
31578
22:38:34,800 --> 22:38:35,800
cheap
31579
22:38:35,760 --> 22:38:36,760
first place to look will often be the
31580
22:38:38,760 --> 22:38:39,760
LED next to the ports where you've
31581
22:38:40,680 --> 22:38:41,680
plugged the cable in if it doesn't light
31582
22:38:42,656 --> 22:38:43,656
up then you've got a number of possible
31583
22:38:45,320 --> 22:38:46,320
reasons the cable's not um plugged in
31584
22:38:48,536 --> 22:38:49,536
properly at both ends the cable could be
31585
22:38:50,872 --> 22:38:51,872
broken somewhere
31586
22:38:52,680 --> 22:38:53,680
now here's um
31587
22:38:54,784 --> 22:38:55,784
the troubleshooting flow chart for fiber
31588
22:38:57,960 --> 22:38:58,960
cable
31589
22:38:59,936 --> 22:39:00,936
um well worth maybe just printing the
31590
22:39:01,800 --> 22:39:02,800
screen and just following it through
31591
22:39:03,240 --> 22:39:04,240
plug it into a different port does that
31592
22:39:05,576 --> 22:39:06,576
Port light up then and it shows you it's
31593
22:39:07,616 --> 22:39:08,616
a problem with the port
31594
22:39:10,376 --> 22:39:11,376
um just a few simple troubleshooting
31595
22:39:11,872 --> 22:39:12,872
steps really
31596
22:39:13,440 --> 22:39:14,440
all right don't look into the cable when
31597
22:39:15,960 --> 22:39:16,960
you've got the other end plugged in
31598
22:39:17,160 --> 22:39:18,160
because the laser will go directly into
31599
22:39:19,192 --> 22:39:20,192
your light and it could cause damage so
31600
22:39:22,256 --> 22:39:23,256
use um you could well you could actually
31601
22:39:24,120 --> 22:39:25,120
point it at um a white object or a wall
31602
22:39:27,480 --> 22:39:28,480
or at your hand
31603
22:39:29,400 --> 22:39:30,400
um but read the documentation that comes
31604
22:39:31,192 --> 22:39:32,192
with the cable to make sure you're doing
31605
22:39:33,480 --> 22:39:34,480
the correct thing there are obviously
31606
22:39:35,824 --> 22:39:36,824
electronic devices that you can also use
31607
22:39:38,696 --> 22:39:39,696
when you can connect two devices such as
31608
22:39:41,464 --> 22:39:42,464
a server adapter to a switch using a
31609
22:39:43,920 --> 22:39:44,920
fiber cable the TX Porter one end should
31610
22:39:46,680 --> 22:39:47,680
always be connected to the RX Porter the
31611
22:39:48,784 --> 22:39:49,784
opposite end normally you'll get a
31612
22:39:51,784 --> 22:39:52,784
housing
31613
22:39:52,856 --> 22:39:53,856
that both ends of the cable will connect
31614
22:39:54,960 --> 22:39:55,960
to and that can only plug in one way to
31615
22:39:58,376 --> 22:39:59,376
the device
31616
22:40:00,056 --> 22:40:01,056
not always the case and obviously
31617
22:40:02,464 --> 22:40:03,464
there's different cable types all over
31618
22:40:04,256 --> 22:40:05,256
the world but um normally you'll
31619
22:40:07,800 --> 22:40:08,800
um
31620
22:40:08,824 --> 22:40:09,824
it'll be designed to be idiot proof so
31621
22:40:11,280 --> 22:40:12,280
we don't um cause that issue if you
31622
22:40:13,744 --> 22:40:14,744
connect it the other way around you'll
31623
22:40:15,176 --> 22:40:16,176
have no connectivity and then um it'll
31624
22:40:18,600 --> 22:40:19,600
show no connection
31625
22:40:20,336 --> 22:40:21,336
as supported distances multi-mod fibers
31626
22:40:22,920 --> 22:40:23,920
with 50 microns and 62 microns can
31627
22:40:26,040 --> 22:40:27,040
support data up to 500 meters and 175
31628
22:40:29,640 --> 22:40:30,640
respectively again read the label it
31629
22:40:32,464 --> 22:40:33,464
comes with your cable in
31630
22:40:35,696 --> 22:40:36,696
um you might you may well be lucky
31631
22:40:36,960 --> 22:40:37,960
enough to have a professional company
31632
22:40:39,240 --> 22:40:40,240
coming into your cabling for you and
31633
22:40:41,936 --> 22:40:42,936
then again you may have to go and swap
31634
22:40:43,976 --> 22:40:44,976
some cable out or install a new device
31635
22:40:45,832 --> 22:40:46,832
without the aid of this company so you
31636
22:40:48,000 --> 22:40:49,000
do need to know
31637
22:40:49,280 --> 22:40:50,280
multi-mad fibers are categorized further
31638
22:40:52,496 --> 22:40:53,496
by Optical multi-mode or om designator
31639
22:40:56,464 --> 22:40:57,464
these are labeled from om1 to om4 just
31640
22:40:59,936 --> 22:41:00,936
check the uh table and
31641
22:41:04,616 --> 22:41:05,616
um you've let you've normally got a
31642
22:41:06,536 --> 22:41:07,536
label on your cable as well to see what
31643
22:41:08,576 --> 22:41:09,576
you do however it's stamped on the side
31644
22:41:10,192 --> 22:41:11,192
and just check the specifications and
31645
22:41:12,656 --> 22:41:13,656
allowances
31646
22:41:13,976 --> 22:41:14,976
when you troubleshoot in check whether
31647
22:41:16,080 --> 22:41:17,080
the cable supports the speed and
31648
22:41:18,360 --> 22:41:19,360
distance of the link between the devices
31649
22:41:22,856 --> 22:41:23,856
Bend radius most fiber optic cables are
31650
22:41:25,856 --> 22:41:26,856
made of glass
31651
22:41:27,000 --> 22:41:28,000
a sharp Bend at some point they are
31652
22:41:29,040 --> 22:41:30,040
pretty flexible but if you bend it too
31653
22:41:30,720 --> 22:41:31,720
much it will break the glass the bend
31654
22:41:32,696 --> 22:41:33,696
radius refers to the smallest bend a
31655
22:41:35,400 --> 22:41:36,400
cable can withstand again if you start
31656
22:41:37,856 --> 22:41:38,856
wrapping this Cable Round and Round a
31657
22:41:40,192 --> 22:41:41,192
pole in order to take up the slack then
31658
22:41:43,144 --> 22:41:44,144
you could well check and break the bend
31659
22:41:45,720 --> 22:41:46,720
radius and rendering the cable
31660
22:41:48,240 --> 22:41:49,240
um unserviceable
31661
22:41:51,600 --> 22:41:52,600
to avoid issues don't bend them
31662
22:41:53,824 --> 22:41:54,824
obviously or more than you have to the
31663
22:41:56,336 --> 22:41:57,336
otdr can be used to check whether the
31664
22:41:58,016 --> 22:41:59,016
cable is damaged
31665
22:41:59,760 --> 22:42:00,760
damage cable obviously needs to be
31666
22:42:02,040 --> 22:42:03,040
replaced hopefully that goes without
31667
22:42:03,424 --> 22:42:04,424
saying
31668
22:42:04,744 --> 22:42:05,744
um the broken cable some people put them
31669
22:42:07,320 --> 22:42:08,320
in a cable box if it's broken make sure
31670
22:42:09,656 --> 22:42:10,656
you dispose of it in um the legal the
31671
22:42:13,144 --> 22:42:14,144
legal manner so you can't throw it onto
31672
22:42:14,760 --> 22:42:15,760
a fire usually you'd have to have it
31673
22:42:16,920 --> 22:42:17,920
professionally uh destroyed or every
31674
22:42:19,856 --> 22:42:20,856
cycled if you've got dirt because it
31675
22:42:22,744 --> 22:42:23,744
uses light on the fiber cables if you've
31676
22:42:25,144 --> 22:42:26,144
got dirt on one end it will cause
31677
22:42:27,296 --> 22:42:28,296
um
31678
22:42:27,832 --> 22:42:28,832
problems High loss and reflectance clean
31679
22:42:31,256 --> 22:42:32,256
it using the cleaning methods and
31680
22:42:34,256 --> 22:42:35,256
supplies provided with the cables don't
31681
22:42:36,656 --> 22:42:37,656
wipe at the end of it on on your
31682
22:42:38,512 --> 22:42:39,512
trousers
31683
22:42:40,936 --> 22:42:41,936
attenuation signal loss over the
31684
22:42:43,440 --> 22:42:44,440
fireball optic cable following could be
31685
22:42:46,144 --> 22:42:47,144
the reasons it could have been over
31686
22:42:47,872 --> 22:42:48,872
stressed during installation improper
31687
22:42:50,336 --> 22:42:51,336
termination improper splicing if it's
31688
22:42:53,336 --> 22:42:54,336
been spliced somewhere could be broken
31689
22:42:55,376 --> 22:42:56,376
fiber again you can use the otdr to
31690
22:42:59,760 --> 22:43:00,760
locate the faults
31691
22:43:01,800 --> 22:43:02,800
wavelength mismatch
31692
22:43:04,192 --> 22:43:05,192
fiber cable uses wavelengths longer than
31693
22:43:06,600 --> 22:43:07,600
a normal light it's usually around 850
31694
22:43:09,960 --> 22:43:10,960
1300 or 1550 newton meters
31695
22:43:14,160 --> 22:43:15,160
multi-mode fiber is designed to operate
31696
22:43:16,192 --> 22:43:17,192
at 850 to 1300
31697
22:43:18,960 --> 22:43:19,960
single mode 13 10 or 1550
31698
22:43:23,872 --> 22:43:24,872
the wavelength is used for transmission
31699
22:43:25,320 --> 22:43:26,320
on the wavelengths that must be tested
31700
22:43:27,120 --> 22:43:28,120
for Signal losses in the cable plants
31701
22:43:32,336 --> 22:43:33,336
now when the mismatch fiber cables are
31702
22:43:34,320 --> 22:43:35,320
coupled the incompatibility of the core
31703
22:43:36,176 --> 22:43:37,176
sizes results in signal loss
31704
22:43:39,056 --> 22:43:40,056
now there's no problem if you're
31705
22:43:40,552 --> 22:43:41,552
transmitting light from a smaller fiber
31706
22:43:42,424 --> 22:43:43,424
core to a larger one but the other way
31707
22:43:44,696 --> 22:43:45,696
around and you'll have signal loss
31708
22:43:48,360 --> 22:43:49,360
the signal loss can be around 20 DB when
31709
22:43:51,784 --> 22:43:52,784
a couple when we could pull a multi-mode
31710
22:43:54,360 --> 22:43:55,360
fiber to a single mode again read the
31711
22:43:57,000 --> 22:43:58,000
documentation that comes with all your
31712
22:43:59,336 --> 22:44:00,336
cable in
31713
22:44:00,600 --> 22:44:01,600
so I've looked at fiber cable supported
31714
22:44:03,000 --> 22:44:04,000
distances and categories the bend radius
31715
22:44:06,240 --> 22:44:07,240
dirt on your connectors attenuation and
31716
22:44:09,832 --> 22:44:10,832
wavelength mismatch and fiber type
31717
22:44:11,760 --> 22:44:12,760
mismatch that's all for now thanks for
31718
22:44:14,104 --> 22:44:15,104
watching
31719
22:44:19,900 --> 22:44:20,900
[Music]
31720
22:44:28,256 --> 22:44:29,256
foreign
31721
22:44:36,256 --> 22:44:37,256
19 lesson 4 common network issues
31722
22:44:39,424 --> 22:44:40,424
there's actually entire books been
31723
22:44:41,936 --> 22:44:42,936
written about troubleshooting Networks
31724
22:44:45,056 --> 22:44:46,056
and from PC switches and routers and
31725
22:44:48,296 --> 22:44:49,296
it's something that requires a bit of
31726
22:44:50,640 --> 22:44:51,640
experience common sense
31727
22:44:52,920 --> 22:44:53,920
and often a plan and sometimes a bit of
31728
22:44:55,616 --> 22:44:56,616
good luck as well and guesswork
31729
22:44:59,160 --> 22:45:00,160
we're going to look at common things
31730
22:45:01,744 --> 22:45:02,744
that normally go wrong day to day
31731
22:45:03,960 --> 22:45:04,960
incorrect default gateway
31732
22:45:06,176 --> 22:45:07,176
broad Customs duplicate IP address your
31733
22:45:09,240 --> 22:45:10,240
duplex and speed mismatches
31734
22:45:11,760 --> 22:45:12,760
incorrect vlans Hardware failures and
31735
22:45:15,000 --> 22:45:16,000
DHCP DNS
31736
22:45:17,576 --> 22:45:18,576
interface misconfiguration cable
31737
22:45:20,280 --> 22:45:21,280
placements
31738
22:45:21,784 --> 22:45:22,784
power failures and then less common MTU
31739
22:45:24,896 --> 22:45:25,896
black hole Nick teaming issues
31740
22:45:28,496 --> 22:45:29,496
so you can create default gateway
31741
22:45:31,256 --> 22:45:32,256
um it depends if there's been a change
31742
22:45:33,536 --> 22:45:34,536
of default gateway
31743
22:45:35,640 --> 22:45:36,640
if the device
31744
22:45:37,800 --> 22:45:38,800
um
31745
22:45:38,512 --> 22:45:39,512
that is experiencing the problems has
31746
22:45:41,104 --> 22:45:42,104
had any changes
31747
22:45:42,832 --> 22:45:43,832
or um somebody's gone in and configured
31748
22:45:46,080 --> 22:45:47,080
something so it all depends on the
31749
22:45:47,576 --> 22:45:48,576
questions you've asked really
31750
22:45:49,192 --> 22:45:50,192
but if you've got the incorrect default
31751
22:45:50,640 --> 22:45:51,640
gateway then all traffic from your host
31752
22:45:53,536 --> 22:45:54,536
device is going to the wrong location
31753
22:45:56,216 --> 22:45:57,216
and Layer Two devices such as switches
31754
22:45:59,216 --> 22:46:00,216
also are normally configured with the
31755
22:46:01,320 --> 22:46:02,320
default gateway but you should be able
31756
22:46:03,600 --> 22:46:04,600
to Ping from the um switch whatever the
31757
22:46:07,376 --> 22:46:08,376
VLAN is to the default gateway when
31758
22:46:09,360 --> 22:46:10,360
you're installing it just to check it's
31759
22:46:10,920 --> 22:46:11,920
working
31760
22:46:12,360 --> 22:46:13,360
so the IP address assigned to the
31761
22:46:14,576 --> 22:46:15,576
default gateway may be correct and you
31762
22:46:16,192 --> 22:46:17,192
can check your IP configuration settings
31763
22:46:19,016 --> 22:46:20,016
on your windows or Linux
31764
22:46:22,016 --> 22:46:23,016
um device
31765
22:46:24,056 --> 22:46:25,056
obviously to fix it put in the correct
31766
22:46:26,104 --> 22:46:27,104
default gateway and make sure nothing's
31767
22:46:27,896 --> 22:46:28,896
changed on the default gateway
31768
22:46:30,000 --> 22:46:31,000
broadcast storms users can experience a
31769
22:46:33,144 --> 22:46:34,144
degradation and network performance and
31770
22:46:36,360 --> 22:46:37,360
it can actually bring down the entire
31771
22:46:37,744 --> 22:46:38,744
network
31772
22:46:39,360 --> 22:46:40,360
so the network is flooded with broadcast
31773
22:46:41,280 --> 22:46:42,280
traffic could be a switching Loop it
31774
22:46:44,696 --> 22:46:45,696
could also be a faulty network card
31775
22:46:46,976 --> 22:46:47,976
that's just sending a huge amount of
31776
22:46:49,552 --> 22:46:50,552
traffic out
31777
22:46:50,872 --> 22:46:51,872
and you could troubleshoot it with
31778
22:46:52,856 --> 22:46:53,856
Wireshark and other programs and Cisco
31779
22:46:55,552 --> 22:46:56,552
provide um a whole raft of tools
31780
22:46:58,496 --> 22:46:59,496
uh obviously having spanning training
31781
22:47:00,424 --> 22:47:01,424
switches will help solve the problem
31782
22:47:02,216 --> 22:47:03,216
it's normally there it's normally on
31783
22:47:04,856 --> 22:47:05,856
their body faults
31784
22:47:06,360 --> 22:47:07,360
duplicate IP sometimes somebody doesn't
31785
22:47:09,056 --> 22:47:10,056
release their DHCP address it's been on
31786
22:47:11,512 --> 22:47:12,512
there too long or stuck for some reason
31787
22:47:13,336 --> 22:47:14,336
or I've seen people manually configure
31788
22:47:16,440 --> 22:47:17,440
an IP address on their system for some
31789
22:47:18,896 --> 22:47:19,896
crazy reason
31790
22:47:20,280 --> 22:47:21,280
I don't know why they did it and it's
31791
22:47:22,144 --> 22:47:23,144
caused a mismatch
31792
22:47:25,256 --> 22:47:26,256
to avoid it you can change the IP
31793
22:47:27,424 --> 22:47:28,424
address of both or one of the hosts and
31794
22:47:30,832 --> 22:47:31,832
normally
31795
22:47:31,920 --> 22:47:32,920
um asking for it to be provided by DHCP
31796
22:47:34,440 --> 22:47:35,440
which most devices use
31797
22:47:36,896 --> 22:47:37,896
speed and duplex mismatch you can have
31798
22:47:39,784 --> 22:47:40,784
on your host or on a switch in fact on a
31799
22:47:42,832 --> 22:47:43,832
router as well
31800
22:47:44,160 --> 22:47:45,160
you'll have slow or degraded Network
31801
22:47:46,440 --> 22:47:47,440
performance or no connection no
31802
22:47:48,656 --> 22:47:49,656
connectivity at all
31803
22:47:50,576 --> 22:47:51,576
and you could have different port and
31804
22:47:52,496 --> 22:47:53,496
speed settings you could have 100 full
31805
22:47:55,144 --> 22:47:56,144
duplex on one side and 10 Meg half
31806
22:47:58,680 --> 22:47:59,680
duplex on the other side and you're
31807
22:48:00,600 --> 22:48:01,600
going to have problems normally you'll
31808
22:48:02,216 --> 22:48:03,216
see issues on the LED of the network
31809
22:48:05,336 --> 22:48:06,336
card as well and you could have um
31810
22:48:08,400 --> 22:48:09,400
error messages coming up on your router
31811
22:48:10,744 --> 22:48:11,744
or switch console and on your PC
31812
22:48:15,784 --> 22:48:16,784
so common causes when negotiation is
31813
22:48:17,936 --> 22:48:18,936
enabled on one side and disabled on the
31814
22:48:19,856 --> 22:48:20,856
other
31815
22:48:22,256 --> 22:48:23,256
it's reliable to manually configure
31816
22:48:24,424 --> 22:48:25,424
network speed and duplex settings for
31817
22:48:26,160 --> 22:48:27,160
the server and other critical links now
31818
22:48:28,976 --> 22:48:29,976
you may use Auto negotiation the
31819
22:48:31,552 --> 22:48:32,552
networks I've worked out they they
31820
22:48:33,424 --> 22:48:34,424
generally didn't
31821
22:48:35,040 --> 22:48:36,040
they had hard-coded and speed and duplex
31822
22:48:39,120 --> 22:48:40,120
settings for all devices
31823
22:48:41,160 --> 22:48:42,160
uh incorrect VLAN if you're on the wrong
31824
22:48:43,320 --> 22:48:44,320
VLAN you may have no connectivity or not
31825
22:48:45,896 --> 22:48:46,896
be able to access the resources that you
31826
22:48:48,360 --> 22:48:49,360
need because it's in a different VLAN
31827
22:48:51,320 --> 22:48:52,320
configuring devices is normally the
31828
22:48:53,512 --> 22:48:54,512
switch Port the end devices don't have
31829
22:48:55,616 --> 22:48:56,616
VLAN settings as a general rule you
31830
22:48:58,680 --> 22:48:59,680
would configure the switch port to be in
31831
22:49:00,784 --> 22:49:01,784
the corrective VLAN and make sure it's
31832
22:49:02,936 --> 22:49:03,936
not blocked that VLAN is unblocked for
31833
22:49:04,976 --> 22:49:05,976
security reasons on the switch trunk
31834
22:49:07,256 --> 22:49:08,256
port
31835
22:49:08,104 --> 22:49:09,104
Hardware failure this is a whole raft of
31836
22:49:10,616 --> 22:49:11,616
things that could go wrong
31837
22:49:11,824 --> 22:49:12,824
intermittently or just completely break
31838
22:49:14,760 --> 22:49:15,760
and one of the components of a device
31839
22:49:16,496 --> 22:49:17,496
may have failed or an entire device you
31840
22:49:19,144 --> 22:49:20,144
identify it with your troubleshooting
31841
22:49:20,760 --> 22:49:21,760
methodology and you can replace the
31842
22:49:23,872 --> 22:49:24,872
faulty device or the faulty interface
31843
22:49:27,496 --> 22:49:28,496
DHCP if this server has been incorrectly
31844
22:49:30,120 --> 22:49:31,120
configured
31845
22:49:31,976 --> 22:49:32,976
then you're obviously going to have
31846
22:49:33,600 --> 22:49:34,600
issues you could have one person
31847
22:49:35,216 --> 22:49:36,216
affected or the entire
31848
22:49:37,376 --> 22:49:38,376
um organization you could exhaust all of
31849
22:49:40,256 --> 22:49:41,256
the IP addresses on your DHCP pool you
31850
22:49:43,800 --> 22:49:44,800
could also indicate that you've got some
31851
22:49:45,784 --> 22:49:46,784
sort of attack going on some Rogue DHCP
31852
22:49:48,832 --> 22:49:49,832
server or the devices causing issues
31853
22:49:52,496 --> 22:49:53,496
we've addressed that elsewhere
31854
22:49:55,976 --> 22:49:56,976
DNS obviously for DNS lookups you need
31855
22:49:59,104 --> 22:50:00,104
to have the correct device configured
31856
22:50:01,856 --> 22:50:02,856
a host can be configured with the wrong
31857
22:50:03,536 --> 22:50:04,536
DNS server either because you've
31858
22:50:05,824 --> 22:50:06,824
misconfigured the DHCP server or
31859
22:50:08,464 --> 22:50:09,464
somebody's hard set it
31860
22:50:10,256 --> 22:50:11,256
so ensure the host is configured with
31861
22:50:12,424 --> 22:50:13,424
the correct IP address of the DNS server
31862
22:50:15,176 --> 22:50:16,176
on Windows you could issue ipconfig
31863
22:50:17,576 --> 22:50:18,576
space forward slash all and it will show
31864
22:50:20,160 --> 22:50:21,160
you your DHCP server address your DNS
31865
22:50:22,744 --> 22:50:23,744
server address
31866
22:50:24,056 --> 22:50:25,056
IP address and a few other
31867
22:50:26,640 --> 22:50:27,640
um settings that you may find
31868
22:50:27,960 --> 22:50:28,960
interesting
31869
22:50:29,824 --> 22:50:30,824
if your interface is incorrectly
31870
22:50:31,976 --> 22:50:32,976
configured you'll have no connectivity
31871
22:50:34,376 --> 22:50:35,376
or intermittent
31872
22:50:36,000 --> 22:50:37,000
you could have the source um or
31873
22:50:37,856 --> 22:50:38,856
destination device may have an incorrect
31874
22:50:39,960 --> 22:50:40,960
IP address or subnet so if if for some
31875
22:50:43,376 --> 22:50:44,376
reason you'll
31876
22:50:45,240 --> 22:50:46,240
um router interfaces on either end have
31877
22:50:47,160 --> 22:50:48,160
been put in different subnets then
31878
22:50:48,896 --> 22:50:49,896
you're not going to get you're not going
31879
22:50:50,336 --> 22:50:51,336
to get connectivity
31880
22:50:52,680 --> 22:50:53,680
check the ipn subnet mask of both source
31881
22:50:56,160 --> 22:50:57,160
and destination and check it against
31882
22:50:57,480 --> 22:50:58,480
your design documents
31883
22:51:00,360 --> 22:51:01,360
cable placement you could have slow
31884
22:51:02,872 --> 22:51:03,872
performance
31885
22:51:04,256 --> 22:51:05,256
and it could be close to a source of Emi
31886
22:51:06,960 --> 22:51:07,960
which we've already discussed
31887
22:51:10,552 --> 22:51:11,552
power failure obviously that's going to
31888
22:51:12,600 --> 22:51:13,600
cause issues either with the device or
31889
22:51:15,120 --> 22:51:16,120
part of the network or the entire
31890
22:51:16,616 --> 22:51:17,616
network
31891
22:51:18,720 --> 22:51:19,720
and most
31892
22:51:20,400 --> 22:51:21,400
um the higher end switches and routers
31893
22:51:22,144 --> 22:51:23,144
have redundant power supplies so that if
31894
22:51:25,016 --> 22:51:26,016
the main one goes down the second does
31895
22:51:27,120 --> 22:51:28,120
backup one takes over
31896
22:51:30,480 --> 22:51:31,480
MTU backholes this is a maximum
31897
22:51:33,360 --> 22:51:34,360
transmission units for your IP packets
31898
22:51:36,720 --> 22:51:37,720
and it depends on configurations it can
31899
22:51:39,000 --> 22:51:40,000
also happen with routing protocols such
31900
22:51:41,040 --> 22:51:42,040
as ospf
31901
22:51:43,376 --> 22:51:44,376
um which is outside the scope of this
31902
22:51:45,240 --> 22:51:46,240
course
31903
22:51:47,400 --> 22:51:48,400
if the packet's been flagged as do not
31904
22:51:49,256 --> 22:51:50,256
fragment then the router is expected to
31905
22:51:51,960 --> 22:51:52,960
send an icmp message destination
31906
22:51:54,056 --> 22:51:55,056
unreachable back to the host that sent
31907
22:51:56,640 --> 22:51:57,640
the packet
31908
22:51:58,920 --> 22:51:59,920
and the router drops the packet and
31909
22:52:00,536 --> 22:52:01,536
doesn't send the icmp message then the
31910
22:52:02,576 --> 22:52:03,576
host to the host and the router is
31911
22:52:04,320 --> 22:52:05,320
referred to as a black hole router
31912
22:52:06,424 --> 22:52:07,424
you can check the interface MTU on your
31913
22:52:09,656 --> 22:52:10,656
routers when you do the show interface
31914
22:52:12,056 --> 22:52:13,056
or you can add um some troubleshooting
31915
22:52:15,120 --> 22:52:16,120
software if it if you don't already have
31916
22:52:17,400 --> 22:52:18,400
it you can use a ping utility or you can
31917
22:52:20,576 --> 22:52:21,576
use a trace route you can send different
31918
22:52:22,920 --> 22:52:23,920
ping sizes and certainly on Cisco
31919
22:52:25,800 --> 22:52:26,800
routers you can go into a detailed menu
31920
22:52:28,104 --> 22:52:29,104
of options or send a ping packet of a
31921
22:52:30,832 --> 22:52:31,832
certain size to see if you're losing
31922
22:52:32,576 --> 22:52:33,576
packets
31923
22:52:34,192 --> 22:52:35,192
Nick teaming for user experiences a
31924
22:52:37,552 --> 22:52:38,552
degradation in network performance it
31925
22:52:40,376 --> 22:52:41,376
could be a Nick teaming misconfiguration
31926
22:52:42,240 --> 22:52:43,240
this is generally done a lot on servers
31927
22:52:45,376 --> 22:52:46,376
and different vendors have different
31928
22:52:49,504 --> 22:52:50,504
terminology for Nick teaming so again
31929
22:52:52,976 --> 22:52:53,976
check your documentation
31930
22:52:55,144 --> 22:52:56,144
uh generally you'll you'll
31931
22:52:58,144 --> 22:52:59,144
aggregate various Network Cards into one
31932
22:53:02,400 --> 22:53:03,400
logical connection
31933
22:53:07,256 --> 22:53:08,256
um so you could have broadcast uh storms
31934
22:53:10,376 --> 22:53:11,376
there'll be other issues as well with
31935
22:53:12,120 --> 22:53:13,120
spanning tree and um other things to
31936
22:53:15,536 --> 22:53:16,536
prevent the Nick team from becoming
31937
22:53:17,512 --> 22:53:18,512
multiple links you can use Link
31938
22:53:19,976 --> 22:53:20,976
aggregation control protocol which is
31939
22:53:23,104 --> 22:53:24,104
used on routers generally
31940
22:53:25,920 --> 22:53:26,920
all right so incorrect develop Gateway
31941
22:53:28,256 --> 22:53:29,256
broadcast storms duplicate IP and speed
31942
22:53:31,192 --> 22:53:32,192
and duplex VLAN assignments on your
31943
22:53:34,016 --> 22:53:35,016
switches check your documentation for
31944
22:53:35,936 --> 22:53:36,936
that and your configurations
31945
22:53:38,160 --> 22:53:39,160
should say Hardware failure sorry
31946
22:53:41,400 --> 22:53:42,400
misconfigured DHCP and DNS
31947
22:53:45,176 --> 22:53:46,176
interface misconfiguration issues cable
31948
22:53:48,120 --> 22:53:49,120
placements
31949
22:53:49,800 --> 22:53:50,800
power failures empty black holes and
31950
22:53:52,440 --> 22:53:53,440
Nick teaming that's all for now thanks
31951
22:53:54,720 --> 22:53:55,720
for watching
31952
22:53:59,600 --> 22:54:00,600
[Music]
31953
22:54:08,296 --> 22:54:09,296
thank you
31954
22:54:16,192 --> 22:54:17,192
welcome to module 20 lesson one change
31955
22:54:18,720 --> 22:54:19,720
management basics
31956
22:54:21,832 --> 22:54:22,832
we're going to look at what is a change
31957
22:54:23,576 --> 22:54:24,576
what is change management types of
31958
22:54:25,920 --> 22:54:26,920
changes and approval processes what is
31959
22:54:28,616 --> 22:54:29,616
documentation in respect of change
31960
22:54:30,600 --> 22:54:31,600
management
31961
22:54:31,920 --> 22:54:32,920
what is a maintenance window
31962
22:54:34,680 --> 22:54:35,680
what is configuration procedures or what
31963
22:54:37,616 --> 22:54:38,616
are
31964
22:54:38,696 --> 22:54:39,696
what is a rollback what is the potential
31965
22:54:41,336 --> 22:54:42,336
impact
31966
22:54:42,360 --> 22:54:43,360
what is the notification to change
31967
22:54:45,144 --> 22:54:46,144
now change management is a new addition
31968
22:54:49,192 --> 22:54:50,192
to the network plus syllabus
31969
22:54:52,144 --> 22:54:53,144
it actually dates back to you can trace
31970
22:54:55,080 --> 22:54:56,080
change the management back to the 1960s
31971
22:54:58,552 --> 22:54:59,552
and now it's a recognized
31972
22:55:01,976 --> 22:55:02,976
um
31973
22:55:02,720 --> 22:55:03,720
qualification and a whole area where you
31974
22:55:06,720 --> 22:55:07,720
can gain employment as a change
31975
22:55:08,400 --> 22:55:09,400
management change manager
31976
22:55:10,976 --> 22:55:11,976
so you could Google change manager and
31977
22:55:14,216 --> 22:55:15,216
ITIL which is the it infrastructure
31978
22:55:16,144 --> 22:55:17,144
Library
31979
22:55:17,160 --> 22:55:18,160
but this is bringing it into alignment
31980
22:55:19,616 --> 22:55:20,616
with prisoners practices where we're
31981
22:55:22,320 --> 22:55:23,320
managing
31982
22:55:23,760 --> 22:55:24,760
um changes and problems also when I
31983
22:55:27,896 --> 22:55:28,896
worked uh Yellow Pages in the UK there
31984
22:55:31,256 --> 22:55:32,256
was a whole Lotto team looking at um
31985
22:55:33,232 --> 22:55:34,232
change management problem management so
31986
22:55:36,424 --> 22:55:37,424
there's systems and procedures for
31987
22:55:38,104 --> 22:55:39,104
everything looking at what we're doing
31988
22:55:40,080 --> 22:55:41,080
why we're doing it who authorizes it if
31989
22:55:43,856 --> 22:55:44,856
there's a problem what caused the
31990
22:55:45,360 --> 22:55:46,360
problem how do we stop the problem
31991
22:55:46,736 --> 22:55:47,736
happening again
31992
22:55:48,424 --> 22:55:49,424
and it makes the entire uh business
31993
22:55:50,760 --> 22:55:51,760
procedure and business run more
31994
22:55:52,552 --> 22:55:53,552
professionally and it cuts down a lot of
31995
22:55:55,144 --> 22:55:56,144
unnecessary
31996
22:55:56,832 --> 22:55:57,832
procedures blaming Communications and
31997
22:56:00,960 --> 22:56:01,960
debriefing and makes the organization
31998
22:56:03,360 --> 22:56:04,360
work more efficiently
31999
22:56:05,400 --> 22:56:06,400
changes any addition removal or
32000
22:56:07,736 --> 22:56:08,736
modification or configuration that could
32001
22:56:09,832 --> 22:56:10,832
have an effect on the IT service so this
32002
22:56:13,256 --> 22:56:14,256
is why we need to have a set of
32003
22:56:15,480 --> 22:56:16,480
procedures in order to plan for a change
32004
22:56:19,144 --> 22:56:20,144
rather than somebody just rebooting one
32005
22:56:22,080 --> 22:56:23,080
of the main cool routers on the network
32006
22:56:24,536 --> 22:56:25,536
at the busiest time of day we need to
32007
22:56:27,656 --> 22:56:28,656
have some sort of procedure
32008
22:56:30,056 --> 22:56:31,056
so change management is a set of
32009
22:56:32,280 --> 22:56:33,280
processes that governs and controls the
32010
22:56:34,256 --> 22:56:35,256
aspects from start to finish it reduces
32011
22:56:36,720 --> 22:56:37,720
the risk disruption and impact on the
32012
22:56:39,360 --> 22:56:40,360
business
32013
22:56:40,440 --> 22:56:41,440
we could refer to it as CM for short
32014
22:56:44,040 --> 22:56:45,040
so CM aims to use the defined standards
32015
22:56:46,552 --> 22:56:47,552
and methods and procedures across
32016
22:56:48,120 --> 22:56:49,120
various teams of groups so we're all
32017
22:56:49,920 --> 22:56:50,920
basically singing off the same hymn
32018
22:56:52,320 --> 22:56:53,320
sheep this is the ITIL the it
32019
22:56:55,616 --> 22:56:56,616
infrastructure Library which we actually
32020
22:56:57,720 --> 22:56:58,720
host and some of the one of the
32021
22:57:00,536 --> 22:57:01,536
qualifications on howturnetwork.com I
32022
22:57:03,424 --> 22:57:04,424
highly recommend it because
32023
22:57:05,216 --> 22:57:06,216
um it people now can't just rely on
32024
22:57:07,504 --> 22:57:08,504
being technical
32025
22:57:08,872 --> 22:57:09,872
they need to have an understanding of
32026
22:57:10,800 --> 22:57:11,800
how they slot into the business and how
32027
22:57:12,480 --> 22:57:13,480
the business works the it works as part
32028
22:57:15,424 --> 22:57:16,424
of the overall business utility breaks
32029
22:57:18,056 --> 22:57:19,056
into service transition service design
32030
22:57:20,040 --> 22:57:21,040
and service operations
32031
22:57:22,144 --> 22:57:23,144
and you can see some of the um things I
32032
22:57:24,720 --> 22:57:25,720
mentioned here you can see change
32033
22:57:26,824 --> 22:57:27,824
management is highlighted there's
32034
22:57:29,040 --> 22:57:30,040
problem management Knowledge Management
32035
22:57:30,832 --> 22:57:31,832
Service testing and validation
32036
22:57:34,376 --> 22:57:35,376
and you slot this into your business how
32037
22:57:37,376 --> 22:57:38,376
your business works and how it's going
32038
22:57:38,936 --> 22:57:39,936
to benefit it
32039
22:57:40,920 --> 22:57:41,920
so change management includes a risk
32040
22:57:43,192 --> 22:57:44,192
assessment reducing change failures
32041
22:57:45,320 --> 22:57:46,320
properly implementing any changes
32042
22:57:47,760 --> 22:57:48,760
looking at business timelines and
32043
22:57:50,160 --> 22:57:51,160
service level agreements
32044
22:57:52,192 --> 22:57:53,192
it gives you better control a clear plan
32045
22:57:55,104 --> 22:57:56,104
for reverting if there's an issue
32046
22:58:00,056 --> 22:58:01,056
I've actually seen this when I had my
32047
22:58:02,760 --> 22:58:03,760
website hosted with a different service
32048
22:58:04,440 --> 22:58:05,440
provider somebody did a change to one of
32049
22:58:07,616 --> 22:58:08,616
the tables on one of the databases and
32050
22:58:10,320 --> 22:58:11,320
it caused outages for around three days
32051
22:58:12,720 --> 22:58:13,720
and I know some people went out of
32052
22:58:14,640 --> 22:58:15,640
business it was just an absolute
32053
22:58:16,080 --> 22:58:17,080
catastrophe and they didn't I don't
32054
22:58:19,016 --> 22:58:20,016
think they had a change management
32055
22:58:20,872 --> 22:58:21,872
procedure in place otherwise they could
32056
22:58:22,616 --> 22:58:23,616
have backed out quite quickly
32057
22:58:24,784 --> 22:58:25,784
I'm managing Communications this is
32058
22:58:27,056 --> 22:58:28,056
important where there's a central person
32059
22:58:29,216 --> 22:58:30,216
is responsible for from communicating
32060
22:58:32,040 --> 22:58:33,040
what's going to happen when it's going
32061
22:58:34,440 --> 22:58:35,440
to happen and then they communicate
32062
22:58:37,504 --> 22:58:38,504
um
32063
22:58:38,160 --> 22:58:39,160
just before it happens and then after to
32064
22:58:40,976 --> 22:58:41,976
say the changes happened and it was
32065
22:58:43,800 --> 22:58:44,800
um a success or failure on what's
32066
22:58:46,016 --> 22:58:47,016
actually
32067
22:58:47,104 --> 22:58:48,104
um the procedure afterwards for
32068
22:58:48,656 --> 22:58:49,656
following up
32069
22:58:51,000 --> 22:58:52,000
changes can be performed to adapt or
32070
22:58:53,040 --> 22:58:54,040
change business needs Hardware software
32071
22:58:55,320 --> 22:58:56,320
it could reactively Implement a fix if
32072
22:58:58,256 --> 22:58:59,256
there's some sort of major issue or bug
32073
22:59:00,720 --> 22:59:01,720
or attack on the network
32074
22:59:03,424 --> 22:59:04,424
normal changes for example a a normal
32075
22:59:06,960 --> 22:59:07,960
configuration or server maintenance
32076
22:59:10,016 --> 22:59:11,016
and something that it was generally
32077
22:59:11,576 --> 22:59:12,576
expected
32078
22:59:12,784 --> 22:59:13,784
standard change is pre-approved changes
32079
22:59:15,232 --> 22:59:16,232
that don't require approvals these are
32080
22:59:17,400 --> 22:59:18,400
things that just aren't going to cause a
32081
22:59:19,376 --> 22:59:20,376
problem usually for example
32082
22:59:22,496 --> 22:59:23,496
um
32083
22:59:23,512 --> 22:59:24,512
swapping out a redundant power supply
32084
22:59:25,552 --> 22:59:26,552
it's just not going to have any impact
32085
22:59:27,424 --> 22:59:28,424
and it's been tested for
32086
22:59:30,120 --> 22:59:31,120
um in the past
32087
22:59:31,920 --> 22:59:32,920
risk associated is low and does not have
32088
22:59:34,144 --> 22:59:35,144
enough adverse adverse effect on the
32089
22:59:36,296 --> 22:59:37,296
business
32090
22:59:37,376 --> 22:59:38,376
emergency these are changes that are
32091
22:59:40,016 --> 22:59:41,016
implemented on an urgent basis through
32092
22:59:42,120 --> 22:59:43,120
and remediate a problem it's normally
32093
22:59:44,512 --> 22:59:45,512
Network effect in business affecting and
32094
22:59:47,040 --> 22:59:48,040
it has to be done urgently you need to
32095
22:59:49,680 --> 22:59:50,680
have approval off um the emergency
32096
22:59:51,720 --> 22:59:52,720
change Advisory Board and they'll
32097
22:59:54,424 --> 22:59:55,424
normally have either a video conference
32098
22:59:56,040 --> 22:59:57,040
or a quick meeting
32099
22:59:57,600 --> 22:59:58,600
in order to talk about the impact on the
32100
23:00:00,360 --> 23:00:01,360
business because you need to look at the
32101
23:00:01,800 --> 23:00:02,800
entire
32102
23:00:02,872 --> 23:00:03,872
um structure
32103
23:00:04,464 --> 23:00:05,464
documentation a change request is
32104
23:00:07,016 --> 23:00:08,016
documented using applications
32105
23:00:09,424 --> 23:00:10,424
there's a variety of
32106
23:00:11,824 --> 23:00:12,824
um applications you can use
32107
23:00:14,160 --> 23:00:15,160
the documentary change request is caused
32108
23:00:16,256 --> 23:00:17,256
a change record it could be online or
32109
23:00:18,056 --> 23:00:19,056
printed issues to track the chains
32110
23:00:20,336 --> 23:00:21,336
throughout its life cycle from beginning
32111
23:00:21,960 --> 23:00:22,960
to end
32112
23:00:23,464 --> 23:00:24,464
this is so we've got an audit trail of
32113
23:00:25,440 --> 23:00:26,440
what happened and who did what and who
32114
23:00:27,176 --> 23:00:28,176
approved it and
32115
23:00:28,736 --> 23:00:29,736
Etc the change record contains key
32116
23:00:31,376 --> 23:00:32,376
details of the change including detail
32117
23:00:33,296 --> 23:00:34,296
tech technical implementation
32118
23:00:36,536 --> 23:00:37,536
the the technical parts will probably be
32119
23:00:38,696 --> 23:00:39,696
read by the um the it managers and
32120
23:00:41,512 --> 23:00:42,512
Technical team but they're there um for
32121
23:00:44,400 --> 23:00:45,400
the record
32122
23:00:46,496 --> 23:00:47,496
key details is who requested it why did
32123
23:00:49,320 --> 23:00:50,320
they request it what's the outcome
32124
23:00:51,600 --> 23:00:52,600
what's the point of doing it is there a
32125
23:00:53,280 --> 23:00:54,280
business benefit or is it going to
32126
23:00:54,784 --> 23:00:55,784
prevent something more serious happening
32127
23:00:57,000 --> 23:00:58,000
what are the risks involved
32128
23:00:59,936 --> 23:01:00,936
what resources that includes the teams
32129
23:01:02,696 --> 23:01:03,696
human resources and physical and
32130
23:01:04,736 --> 23:01:05,736
software resources
32131
23:01:06,656 --> 23:01:07,656
for example a network card needs
32132
23:01:08,824 --> 23:01:09,824
replacing or an update required for the
32133
23:01:11,464 --> 23:01:12,464
software
32134
23:01:12,536 --> 23:01:13,536
who's responsible for building testing
32135
23:01:14,696 --> 23:01:15,696
and implementing what's the relationship
32136
23:01:17,280 --> 23:01:18,280
between this change and other changes is
32137
23:01:19,440 --> 23:01:20,440
it one of a series
32138
23:01:22,736 --> 23:01:23,736
so the effect of one change on another
32139
23:01:24,784 --> 23:01:25,784
for example if you update a VLAN on a
32140
23:01:27,720 --> 23:01:28,720
certain device what devices what
32141
23:01:30,176 --> 23:01:31,176
physical ports are going to be affected
32142
23:01:31,800 --> 23:01:32,800
is the VLAN going to be propagated on
32143
23:01:34,192 --> 23:01:35,192
other switches or does it need to be
32144
23:01:35,696 --> 23:01:36,696
blocked
32145
23:01:37,320 --> 23:01:38,320
maintenance window I'm sure you've heard
32146
23:01:38,936 --> 23:01:39,936
of it's an agreed period of time in
32147
23:01:41,280 --> 23:01:42,280
which is going to have minimal
32148
23:01:42,784 --> 23:01:43,784
disruption
32149
23:01:44,400 --> 23:01:45,400
normally done on the weekends or out of
32150
23:01:47,040 --> 23:01:48,040
hours just depends on your business uh
32151
23:01:49,696 --> 23:01:50,696
procedures the author authorized
32152
23:01:52,616 --> 23:01:53,616
maintenance Windows predetermined and
32153
23:01:54,176 --> 23:01:55,176
pre-approved to carry out the change a
32154
23:01:56,336 --> 23:01:57,336
lot of the time
32155
23:01:57,480 --> 23:01:58,480
um an alternative
32156
23:01:59,104 --> 23:02:00,104
our server is used or whatever
32157
23:02:02,696 --> 23:02:03,696
um
32158
23:02:03,296 --> 23:02:04,296
you could have some sort of load
32159
23:02:04,680 --> 23:02:05,680
balancer used on all traffic is just
32160
23:02:06,960 --> 23:02:07,960
sent through one of the load balances so
32161
23:02:09,960 --> 23:02:10,960
the change could actually be transparent
32162
23:02:11,872 --> 23:02:12,872
to users
32163
23:02:13,552 --> 23:02:14,552
generally changes during weekdays are
32164
23:02:15,424 --> 23:02:16,424
scheduled after business hours critical
32165
23:02:17,872 --> 23:02:18,872
changes Friday nights and they can run
32166
23:02:20,160 --> 23:02:21,160
into the weekend so you can roll back
32167
23:02:22,496 --> 23:02:23,496
and recover if there's an issue
32168
23:02:25,192 --> 23:02:26,192
or changes to service assets and config
32169
23:02:27,896 --> 23:02:28,896
configuration items are recorded in the
32170
23:02:31,016 --> 23:02:32,016
configuration management system
32171
23:02:34,256 --> 23:02:35,256
uh server can move from pre-production
32172
23:02:36,536 --> 23:02:37,536
to production with a formal sign off
32173
23:02:38,336 --> 23:02:39,336
before it's accepted into production
32174
23:02:41,040 --> 23:02:42,040
such changes are to be documented for
32175
23:02:43,320 --> 23:02:44,320
timely support so everyone needs to know
32176
23:02:45,232 --> 23:02:46,232
about the fact this new server has been
32177
23:02:47,216 --> 23:02:48,216
introduced the configuration settings
32178
23:02:49,256 --> 23:02:50,256
and what the possible risks are and what
32179
23:02:51,960 --> 23:02:52,960
we do if there is a an issue
32180
23:02:55,440 --> 23:02:56,440
our rollback is basically going back to
32181
23:02:57,536 --> 23:02:58,536
how we were before this change happened
32182
23:02:59,872 --> 23:03:00,872
not always possible obviously especially
32183
23:03:03,120 --> 23:03:04,120
if something's completely broken and has
32184
23:03:05,040 --> 23:03:06,040
to be replaced and then the replacement
32185
23:03:07,016 --> 23:03:08,016
for example is broken also
32186
23:03:12,480 --> 23:03:13,480
okay so worst case there's a site
32187
23:03:14,576 --> 23:03:15,576
failover or business continuity plan may
32188
23:03:16,920 --> 23:03:17,920
be invoked this is if the entire core
32189
23:03:20,280 --> 23:03:21,280
system goes down is there some sort of
32190
23:03:22,856 --> 23:03:23,856
backup in place or what do we do
32191
23:03:25,016 --> 23:03:26,016
looking at the impact
32192
23:03:28,144 --> 23:03:29,144
there's a matrix low impact and low risk
32193
23:03:30,896 --> 23:03:31,896
category for going all the way to
32194
23:03:33,176 --> 23:03:34,176
category one which is high impact high
32195
23:03:35,760 --> 23:03:36,760
risk and it's a critical category low
32196
23:03:37,856 --> 23:03:38,856
medium high and critical
32197
23:03:40,440 --> 23:03:41,440
the notification to change is published
32198
23:03:43,256 --> 23:03:44,256
with the details of the change activity
32199
23:03:45,000 --> 23:03:46,000
the window of the change obviously it
32200
23:03:47,640 --> 23:03:48,640
only goes out to the people that are
32201
23:03:49,256 --> 23:03:50,256
going to be impacted
32202
23:03:51,656 --> 23:03:52,656
all right so we've looked at change
32203
23:03:52,976 --> 23:03:53,976
change management types of changes and
32204
23:03:55,144 --> 23:03:56,144
approvals what is documentation
32205
23:03:57,896 --> 23:03:58,896
what is a maintenance window
32206
23:03:59,720 --> 23:04:00,720
configuration procedures and rollbacks
32207
23:04:02,216 --> 23:04:03,216
impact and the notification to change
32208
23:04:04,976 --> 23:04:05,976
that's all for now thanks for watching
32209
23:04:10,080 --> 23:04:11,080
[Music]
32210
23:04:19,760 --> 23:04:20,760
thank you
32211
23:04:27,480 --> 23:04:28,480
welcome to module 21 lesson one Internet
32212
23:04:30,600 --> 23:04:31,600
of Things Technologies this is one of
32213
23:04:33,232 --> 23:04:34,232
the new subjects has been added to the
32214
23:04:35,640 --> 23:04:36,640
latest uh come to exam
32215
23:04:38,336 --> 23:04:39,336
they just expected to have an overview
32216
23:04:40,376 --> 23:04:41,376
of what these things do rather than any
32217
23:04:42,424 --> 23:04:43,424
detail because there's quite a diverse
32218
23:04:44,696 --> 23:04:45,696
array of protocols here said wave and
32219
23:04:48,296 --> 23:04:49,296
plus Bluetooth which I'm sure you've
32220
23:04:50,760 --> 23:04:51,760
heard of NFC
32221
23:04:53,104 --> 23:04:54,104
uh infrared
32222
23:04:54,832 --> 23:04:55,832
RFID
32223
23:04:57,120 --> 23:04:58,120
so Internet of Things
32224
23:04:59,104 --> 23:05:00,104
it's a network of devices appliances
32225
23:05:01,920 --> 23:05:02,920
Vehicles physical devices and many of
32226
23:05:05,040 --> 23:05:06,040
them work with sensors or softwares so
32227
23:05:07,376 --> 23:05:08,376
for example when you're uh so let me go
32228
23:05:11,104 --> 23:05:12,104
down there's a car here actually
32229
23:05:13,800 --> 23:05:14,800
you'll have a sensors on your car
32230
23:05:18,232 --> 23:05:19,232
I know I didn't want any awards for
32231
23:05:19,680 --> 23:05:20,680
drawing centers on your car breaks
32232
23:05:23,936 --> 23:05:24,936
uh which has been detected by a gold
32233
23:05:27,480 --> 23:05:28,480
goes into a CPU of some sort
32234
23:05:30,360 --> 23:05:31,360
when it detects it the wear is down and
32235
23:05:32,576 --> 23:05:33,576
say you've got 30 left then it will
32236
23:05:35,296 --> 23:05:36,296
communicate to the uh garage
32237
23:05:39,600 --> 23:05:40,600
a computer in the garage that will all
32238
23:05:41,824 --> 23:05:42,824
down whatever part you need from the
32239
23:05:43,616 --> 23:05:44,616
manufacturer that will go to the garage
32240
23:05:45,960 --> 23:05:46,960
and then you probably depending on how
32241
23:05:48,424 --> 23:05:49,424
advanced the car is have a notification
32242
23:05:50,640 --> 23:05:51,640
that your tires are worn or your garage
32243
23:05:53,936 --> 23:05:54,936
next time you take it in for a service
32244
23:05:56,512 --> 23:05:57,512
we'll have the part in stock
32245
23:05:58,736 --> 23:05:59,736
and um we'll be able to replace it
32246
23:06:01,504 --> 23:06:02,504
that's just one example of The Internet
32247
23:06:03,056 --> 23:06:04,056
of Things there's many of many of those
32248
23:06:04,920 --> 23:06:05,920
and it's just a phrase that was coined
32249
23:06:07,016 --> 23:06:08,016
several years ago said wave is a
32250
23:06:10,080 --> 23:06:11,080
Wireless Communications protocol used
32251
23:06:13,144 --> 23:06:14,144
mainly for home automation for example
32252
23:06:15,296 --> 23:06:16,296
your lighting your security your
32253
23:06:17,216 --> 23:06:18,216
thermostats to set it and all your
32254
23:06:19,192 --> 23:06:20,192
favorite settings works over a mesh
32255
23:06:21,480 --> 23:06:22,480
networks all the devices are
32256
23:06:24,000 --> 23:06:25,000
um interconnected
32257
23:06:25,680 --> 23:06:26,680
and is controlled by a keypad or you can
32258
23:06:28,256 --> 23:06:29,256
have a key fob of some sort
32259
23:06:30,360 --> 23:06:31,360
and plus
32260
23:06:32,040 --> 23:06:33,040
it's a wireless communication protocol
32261
23:06:34,016 --> 23:06:35,016
again monitor sensor data this could be
32262
23:06:37,680 --> 23:06:38,680
your heart rate tire pressure television
32263
23:06:40,496 --> 23:06:41,496
any number of things and it's created
32264
23:06:43,616 --> 23:06:44,616
and managed by the ant Alliance it's
32265
23:06:45,360 --> 23:06:46,360
actually a subsidiary of Garmin who do
32266
23:06:47,936 --> 23:06:48,936
uh the satellite technology
32267
23:06:51,360 --> 23:06:52,360
a Bluetooth mesh adopted in 2017 it's
32268
23:06:55,504 --> 23:06:56,504
many to many Communications
32269
23:06:58,736 --> 23:06:59,736
so the receiver can be a thing a group
32270
23:07:00,600 --> 23:07:01,600
of things or many things for example
32271
23:07:02,760 --> 23:07:03,760
you'd compare that to the unicast
32272
23:07:05,104 --> 23:07:06,104
multicast or broadcast
32273
23:07:07,616 --> 23:07:08,616
all messages are encrypted and
32274
23:07:09,424 --> 23:07:10,424
authenticated so it's pretty secure
32275
23:07:13,320 --> 23:07:14,320
are you sorry you can ignore that one
32276
23:07:16,080 --> 23:07:17,080
near field communications
32277
23:07:19,800 --> 23:07:20,800
a set of communication protocols you're
32278
23:07:22,080 --> 23:07:23,080
probably using this already it allows
32279
23:07:23,936 --> 23:07:24,936
two devices one's usually a smartphone
32280
23:07:25,976 --> 23:07:26,976
to communicate
32281
23:07:28,976 --> 23:07:29,976
now you need to be within four
32282
23:07:30,296 --> 23:07:31,296
centimeters of each other so you have to
32283
23:07:31,800 --> 23:07:32,800
be pretty close use for contactless
32284
23:07:34,144 --> 23:07:35,144
payments I know on my phone I can enable
32285
23:07:36,424 --> 23:07:37,424
it to act as my card credit card or
32286
23:07:40,552 --> 23:07:41,552
debit card and swipe for my phone
32287
23:07:42,720 --> 23:07:43,720
instead of my card quite handy if you've
32288
23:07:45,296 --> 23:07:46,296
forgotten your wallet somewhere as well
32289
23:07:46,616 --> 23:07:47,616
and you need to pay for something
32290
23:07:49,104 --> 23:07:50,104
infrared I'll go I'm sure you've heard
32291
23:07:51,480 --> 23:07:52,480
of that we used to have um this used to
32292
23:07:53,336 --> 23:07:54,336
be the competitor to wireless where
32293
23:07:55,680 --> 23:07:56,680
companies would add an infrared
32294
23:07:57,656 --> 23:07:58,656
communication module on top of their
32295
23:07:59,760 --> 23:08:00,760
building
32296
23:08:01,016 --> 23:08:02,016
and as long as they had line the site
32297
23:08:02,464 --> 23:08:03,464
they could get high-speed Communications
32298
23:08:03,960 --> 23:08:04,960
with another building then I can't
32299
23:08:06,000 --> 23:08:07,000
remember what the range was but um it
32300
23:08:08,280 --> 23:08:09,280
fell by the wayside really
32301
23:08:10,320 --> 23:08:11,320
it's similar to visible light but
32302
23:08:12,056 --> 23:08:13,056
slightly longer wavelength
32303
23:08:14,400 --> 23:08:15,400
for example your remote control
32304
23:08:17,696 --> 23:08:18,696
you click that and per second of holding
32305
23:08:20,216 --> 23:08:21,216
down the button it sends out 38 000
32306
23:08:22,256 --> 23:08:23,256
signals
32307
23:08:24,656 --> 23:08:25,656
used in Internet things for medical
32308
23:08:26,280 --> 23:08:27,280
Diagnostics fire detection remote gas
32309
23:08:29,760 --> 23:08:30,760
leak detention air detection
32310
23:08:32,104 --> 23:08:33,104
RFID you probably see this if you saw
32311
23:08:34,736 --> 23:08:35,736
the uh the newest not the newest porn
32312
23:08:36,832 --> 23:08:37,832
film
32313
23:08:37,736 --> 23:08:38,736
a bone film um with Jeremy uh I forgot
32314
23:08:41,824 --> 23:08:42,824
his name now
32315
23:08:43,552 --> 23:08:44,552
JB right now we had one of these
32316
23:08:45,600 --> 23:08:46,600
inserted in him and they tried to uh
32317
23:08:47,536 --> 23:08:48,536
unfortunately tried to shoot him with a
32318
23:08:49,504 --> 23:08:50,504
missile so I had to cut it out
32319
23:08:51,600 --> 23:08:52,600
let's um yes it's essential to the
32320
23:08:54,176 --> 23:08:55,176
operation on the Internet of Things
32321
23:08:55,552 --> 23:08:56,552
allows computers to manage all
32322
23:08:57,232 --> 23:08:58,232
individual things this is compared in
32323
23:08:59,280 --> 23:09:00,280
the picture to a grain of rice so it's
32324
23:09:00,784 --> 23:09:01,784
pretty smart
32325
23:09:02,040 --> 23:09:03,040
uses Emi fields to identify and track
32326
23:09:04,920 --> 23:09:05,920
tags it up and attached to objects
32327
23:09:08,216 --> 23:09:09,216
the attack can actually contain the
32328
23:09:09,720 --> 23:09:10,720
electronically stored information so
32329
23:09:13,192 --> 23:09:14,192
this is what's used to Target pets
32330
23:09:16,616 --> 23:09:17,616
for example when will a pet gets lost
32331
23:09:19,616 --> 23:09:20,616
somewhere it can be tagged
32332
23:09:21,784 --> 23:09:22,784
also using tracking Vehicles if you've
32333
23:09:24,120 --> 23:09:25,120
ever seen a production line there's tags
32334
23:09:25,856 --> 23:09:26,856
inserted on the vehicle and that updates
32335
23:09:27,960 --> 23:09:28,960
the entire production system as to if
32336
23:09:29,760 --> 23:09:30,760
it's going too fast too slow and when to
32337
23:09:32,512 --> 23:09:33,512
expect the next vehicle along
32338
23:09:35,872 --> 23:09:36,872
all right so we've covered just in brief
32339
23:09:37,856 --> 23:09:38,856
the Z Wave amp plus Bluetooth NFC IR
32340
23:09:40,976 --> 23:09:41,976
RFID just you need to be aware of these
32341
23:09:44,160 --> 23:09:45,160
in case one of the questions pops up in
32342
23:09:46,256 --> 23:09:47,256
the exam
32343
23:09:47,280 --> 23:09:48,280
that's all thanks for watching2416899
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