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The biggest challenge of learning networking is the fact that, well networking is incredibly complicated
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to date.
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Now complicated is good, complicated means convenient.
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For example I can fire my iPhone and I can get right onto the Internet and check the traffic, whatever
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I need to do. My tv in my house is connected to the Internet and I can do Netflix and all kinds of cool
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stuff. Even in my house.
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the electric meter on the back of my house is connected to the Internet.
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So networking today because of the Internet is fabulously complicated.
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Well complicated is good but it's not a good way to learn about networking.
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So to appreciate networking what I want to do is simplify things a little bit.
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Let's go back in time and to do that I want to show you these old guys here.
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This is a NIC or a network interface card.
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Traditionally these are plugged into individual computers
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and then we use this big chunk of cable right here to connect to a box, which at least for the moment,
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I'm going to call a hub.
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This box acts as the interface to allow lots of computers, well at least in this case eight computers,
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to interconnect with each other so that they can share resources.
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Now when I say share resources a resource can be anything from a web page to a Microsoft Word document
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to a LAN server playing World of Tanks.
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It doesn't really matter to me, but it's just something that somebody can share with somebody else.
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As a matter of fact because this is only local,
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this is where the term local area network came from,
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we'll develop that more in other episodes in the series.
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But for now that will work.
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Now the thing is is that if I've got all of these computers connected to each other how are they actually
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sending data.
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If I've got one computer with a Microsoft Word document and I've got another computer where that person
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wants to access that Microsoft Word document, how does the data actually move through all these little
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cables? Now to appreciate how that works.
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You have to go back a little bit and understand that we're talking about binary data being sent. Now
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I don't care if it's a copper cable with electricity going up and down or if it's a fiber optic cable
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with light turning on or off or even if it's a wireless network where radio frequency basically says
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on and off it's always ones and zeros on and off.
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So if you really want to see data being moved along these cables it looks kind of like this.
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Wow that's really good there.
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The idea is that it's kind of like a Morse code that's being sent between devices and these devices
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understand that code and they can actually do things with it like recreate a Microsoft Word document
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or whatever it might be.
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Now the thing you really need to appreciate, and this is the cornerstone of everything that's networking,
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if there's one thing I'm going to make sure you understand before you run away, is that this data is
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not sent in big long continuous streams.
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It's sent in discrete chunks that are called, traditionally they're called frame's although you hear the
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word packets as well.
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Again there is some difference and in other episodes in the series we'll qualify that.
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So if you really want to understand what's going on what I need you to do is visualize discrete chunks
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of ones and zeros that are flying back and forth across your wires on your network.
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So they look, if you want to see what a frame looks like it looks something, well kind of like this. This
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big stream of ones and zeros that are running across the screen,
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now notice that they start and then they stop and then another chunk comes along and another chunk,
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are what frames really are.
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And we call this packetized data.
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So in order to appreciate packetized data, and trust me packet data is the cornerstone of networking,
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we need to do something to analogize the concept a little bit and,
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well I like to play so let's use some blocks.
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Yay! Fun blocks to play with.
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Now this block is going to represent a frame so let's bring our frame back here.
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OK.
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Now if you take a look at this frame you'll notice it's all the ones and zeros like we saw before.
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Now the thing you need to appreciate is that a single frame can be up to fifteen hundred bytes long.
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So if there's 8 bits to a byte.
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So that would be just around 10000 ones and zeros to represent one single frame.
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So if we scale this down a little bit you can't even see the ones and zeros.
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So because frames are relatively long so that's just how they show up.
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And that's part of why we use these little blocks to represent individual frames.
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So a frame is actually generated inside the network card data comes down, from whatever applications
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Microsoft Word or web browsers or whatever it might be comes down, into the network card itself. The network
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card creates the frame and shoots it out into the network. Equally
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frames are eaten up by network cards. As a frame comes into a network card
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the data is pulled away sent up to whatever software needs it and that it's actually wiped out within
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the network card itself.
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So to appreciate a frame what we need to understand is that we use blocks like this as a representation.
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Frames are always going to be a maximum of fifteen hundred bytes and they have a discrete beginning and a discrete
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end.
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And remember frames are created and eaten up within the network card itself.
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