All language subtitles for Free-CCNA-Software-Defined-Networking-Day-62-CCNA-200-301-Complete-Course_en

This is a free, complete course for the CCNA.

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In this video we will look at software-defined\nnetworking.

In the first video of this network automation\n

such as centralizing the control plane in\n

So, in this video we’ll take a more in-depth\n

We’ll cover exam topics 6.3 and 6.4.

You’ll learn new terms like overlay, underlay,\n

SDN that we haven’t covered yet.

Here’s what we’ll cover in this video.

First I’ll briefly review the points about\n

Then I’ll introduce Cisco’s SD-Access,\n

I’ll also introduce Cisco’s DNA Center\n

part of SD-Access, and compare it to traditional\n

Make sure to watch until the end of the video\n

ExSim, the best practice exams for the CCNA.

Let’s reviews some points about SDN.

SDN is an approach to networking that centralizes\n

Traditional control planes use a distributed\n

device has its own control plane.

The control planes of each network device\n

each other and share routing information,\n

That’s a distributed control plane.

An SDN controller centralizes control plane\n

Network devices no longer use OSPF to share\n

share information with the controller, which\n

Now, depending on the SDN solution the entire\n

SDN controller, or perhaps only part of the\n

functions on the individual network devices.

The controller can interact programmatically\n

Specifically it uses what we call the southbound\n

Then there is also the northbound interface,\n

controller using our scripts and applications.

Okay, those are the fundamental points of\n

And here’s one more look at the SDN architecture\n

The applications are on top, the controller\n

Actually, these three ‘layers’ of the\narchitecture have names.

On top there is the application layer.

This layer contains scripts and applications\n

Note that this isn’t the application layer\n

We’re not talking about the OSI model here.

Anyway, next is the control layer.

This contains the SDN controller that receives\n

Although this is a separate concept from the\n

contains the centralized control plane of\nthe network.

And finally there is the infrastructure layer,\n

responsible for forwarding messages across\nthe network.

I didn’t mention these layers in earlier\n

The application layer contains apps and scripts\n

layer contains the SDN controller, and the\n

Okay, so I’ve told you the basics of what\n

looked at a specific example of SDN.

So, let’s take a look at one, Cisco Software-Defined\nAccess.

Cisco SD-Access is Cisco’s SDN solution\n

So, office wired and wireless LANs, for example.

Cisco has other SDN solutions, for example\n

their SDN solution for automating data center\nnetworks.

Remember when I explained spine-leaf architecture\n

That is used extensively in ACI data center\nnetworks.

Cisco also has SD-WAN, their SDN solution\nfor automating WANs.

But for now let’s look at SD-Access.

Cisco DNA, Digital Network Architecture, Center\n

In the previous video about REST APIs we sent\n

Okay, let’s look at the basic SD-Access\narchitecture.

At the center, in the control layer, we have\nDNA Center.

And then under it we have the network devices\n

These devices form the fabric of SD-Access,\n

In the application layer we have our scripts\n

These could be tools we develop, third-party\n

DNA Center itself also has a GUI that we can\nuse to control it.

Okay, so that’s the basic architecture of\nCisco’s SD Access.

Notice how it fits perfectly into the SDN\n

Next let’s look at that term ‘fabric’.

To understand the fabric, you need to understand\n

First, the underlay is the underlying physical\n

and wireless, which provide IP connectivity,\n

Usually I’d use OSPF as an example, since\n

protocol, but soon you’ll see why I chose\n

Basically the underlay is a bunch of multilayer\n

Then the overlay is the virtual network built\n

For example, SD-Access uses a protocol called\n

And fabric is the term we use to refer to\n

the physical and virtual network as a whole.

For example, this is the underlay network.

The physical multilayer switches and their\n

perhaps running IS-IS to share routing information\n

Then the overlay network consists of VXLAN\n

When hosts in the LAN communicate with each\n

And the fabric refers to the physical and\n

Both are necessary to make SD-Access work.

Okay, now let me give a little more detail\n

So, let’s talk about the underlay.

The underlay’s purpose is to support the\n

To make a virtual network of tunnels, the\n

to reach other of course, so the underlay\nis very important.

There are three different roles for switches\nin SD-Access.

Those are edge node, these are switches that\n

Then there are border nodes, which connect\n

for example connecting to a WAN router.

And finally there are control nodes, which\n

Protocol, to perform various control plane\nfunctions.

I think LISP is far beyond what you need to\n

used for the control plane of SD-Access.

Note that you can add SD-Access on top of\n

This is called a brownfield deployment, when\n

If you’re curious which hardware supports\n

matrix’, but you don’t have to know the\n

And also note that in this case DNA center\n

could be a major risk to the current working\nproduction network.

Ideally you will be using a greenfield deployment,\n

In this case DNA center will configure the\n

For example, all switches are layer 3 and\n

That’s why I mentioned IS-IS in the example\nearlier.

Additionally all links between switches are\n

And edge nodes, so access switches, act as\n

This is known as a routed access layer, we’ve\n

switches that end hosts connect to.

Let me demonstrate with a diagram.

Notice that STP is used to avoid layer 2 loops,\n

the distribution layer switches to provide\n

So, to send traffic out of their local network,\n

In an SD-access underlay, however, all connections\n

used to exchange routing information.

Note that STP is no longer needed, and an\n

Instead, the access layer switches are the\n

Now we have a routed access layer.

Now let me briefly introduce a few aspects\n

First, LISP provides the control plane of\nSD-Access.

A list of mappings of EIDs to RLOCs is kept.

EIDs, endpoint identifiers, identify end hosts\n

locators, identify the edge switch which can\n

Of course, there is a lot more detail to cover\n

can see how it differs from the traditional\ncontrol plane.

Instead of a traditional routing table to\n

Cisco TrustSec, CTS, provides policy control\n

Just remember that name, Cisco TrustSec, you\n

And finally VXLAN provides the data plane\n

actually forward traffic in the data plane.

Let’s look at how VXLAN tunnels work with\nLISP.

Notice that SW3 is a control node, so it is\n

PC2 is connected to SW2, and it tells the\n

Now PC1 wants to send traffic to PC2, so it\n

SW1 asks SW3, how can I reach PC2?

And SW3 informs it that PC2 is reachable via\nSW2.

So, the message from PC1 is forwarded over\n

Okay, that’s all I’ll say about the overlay\nfor now.

VXLAN does more than just create tunnels,\n

which I won’t get into in this video.

Just know the difference between fabric, overlay,\n

like edge node, border node, and control node,\n

Now let’s look a bit more at DNA Center.

DNA Center itself has two main roles.

First, it is the SDN controller used in SD-Access,\n

Additionally it can be a network manager in\n

In that case, although it doesn’t provide\n

point to monitor, analyze, and configure the\nnetwork.

Although I will mention both purposes, for\n

Note that DNA Center is a software application\n

I mentioned Cisco UCS in the virtualization\n

DNA Center has a REST API, as you already\n

And its southbound interface supports protocols\n

protocols Telnet, SSH, and SNMP to control\nand monitor devices.

DNA Center enables something called intent-based\n

Basically, the goal is to allow the engineer\n

to DNA Center, and then DNA Center will take\n

It simplifies the process, and allows engineers\n

analyzing and configuring policies on devices\none at a time.

Traditional security policies using ACLs can\n

For example, ACLs can have thousands of entries,\n

with time and as engineers leave and new engineers\ntake over.

Looking at another engineer’s configurations\n

And configuring and applying ACLs correctly\n

DNA Center, on the other hand, allows the\n

for example this group of users can’t communicate\n

this server but not that server, etc, and\n

This is what configuring policies on DNA Center\nlooks like.

Notice on the left here we have source groups.

Of course, you’d have to define the groups\n

And here we have those same groups as destination.

Up here we have the legend for the colors\nin the policy grid.

Note that the entire grid is white now, so\ndefault.

However, let’s say any traffic sourced from\n

for the Test_Servers group should be permitted.

Now, what about traffic sourced from the guest\ngroup?

They shouldn’t be able to access our servers,\n

How about users in the employees group?

Maybe that depends on various factors, we\n

we would want to make a custom policy for\nthat.

We can go ahead and define policies like this,\n

of creating and applying policies across the\n

No need to configure policies on devices one\nat a time.

I’m not showing the whole process here of\n

engineer can write an explanation for each\n

Okay, now let’s take a look at some of the\n

In the menu on the left side you can see there\n

Here we can build the network hierarchy, manage\n

DNS servers, etc, among other things.

Here, for example, I’m looking at one site,\nSJC-20, on a map.

You can map your enterprise’s sites all\n

In the policy menu you can configure policies\n

You tell DNA Center how the network devices\n

that into configurations on the devices in\nthe network.

For example, here’s that group-based access\ncontrol page again.

A simple and logical way to configure network\npolicies.

In the provision menu we can manage our device\n

Other services are available as well, as you\n

In the side bar you can see that there are\n

By default, when you add devices to DNA Center\n

you assign them to a specific site.

You can see their status of ‘managed’\n

DNA Center, they are not independent devices.

This is also the default setting when you\n

Here you can see the compliance status of\nthe devices.

The top device is compliant with our policies,\n

I clicked on one of the non-compliant devices,\n

The software image, the version of IOS, is\nnot up to date.

The version should be 17.03.03, but currently\nit is 16.11.1c.

We can use DNA Center to update that later\nif we want.

And here you can see that it is also non-compliant\n

Anyway moving on, in the assurance section\n

You can make sure the devices are all up and\n

For example, here I can see which devices\n

3 of 4 devices are in good health, and 1 of\n

Okay, that’s all we’ll look at for now,\n

yourself you can check out the DevNet sandbox\n

the username and password here.

I highly recommend checking it out and looking\n

Okay, that was a quick look at DNA Center,\n

with all of the functions of DNA Center for\nthe CCNA.

Basically, just understand its role as a network\n

also understand that it can be a network management\n

However, the exam topics do state that you\n

device management with traditional device\nmanagement.

Actually, I’ve covered most of these points\n

but let’s review to make sure.

First, let’s review some characteristics\n

Devices are configured one-by-one via SSH\nor console connection.

This is what we’ve been doing throughout\n

Devices are manually configured via console\n

This means when deploying a new device to\na network.

You first have to manually set it up before\n

Configurations and policies are managed per-device,\n

There is no central management.

New network deployments take a long time due\n

Setting up dozens of new devices manually\n

are more likely due to increased manual effort.

Now, I don’t want to make it seem like traditional\n

be aware of these potential downsides.

Now some characteristics of DNA Center-based\nnetwork management.

Devices are centrally managed and monitored\n

In this video I showed you the DNA Center\n

can be used to interact with DNA Center too.

With DNA Center, the administrator communicates\n

which changes those intentions into configurations\n

Configurations and policies are centrally\n

Software versions are also centrally managed.

DNA Center can monitor cloud servers for new\n

In this video you saw an example of DNA Center\n

Finally, with DNA Center new network deployments\n

New devices can automatically receive their\n

Not only is this faster, human error is reduced\n

Okay, that’s all I’ll say about this.

Most of these points we have already covered,\n

it is mentioned on the exam topics.

Okay, let’s review what we covered.

We first reviewed SDN, and I newly introduced\n

Then, as an example of SDN, I introduced some\n

The main takeaways from this section are the\n

Make sure you understand those concepts.

Then I showed you some functions of Cisco\n

with DNA Center to traditional network management.

Remember, DNA Center is an SDN controller\n

be used as a general network management tool\n

Make sure to watch until the end of the quiz\n

ExSim, the best practice exams for the CCNA.

Okay, let’s go to quiz question 1.

Which of the following terms describes the\n

Pause the video now to select the best answer.

Okay, the answer is A, underlay.

The underlay refers to the underlying physical\n

The combination of underlay and overlay is\ncalled the fabric.

In which of the following layers would you\n

Pause the video now to select the best answer.

Okay, the answer is B, application.

In SDN architecture, the application layer\n

to interact with the controller, which is\nin the control layer.

Finally the bottom layer is the infrastructure\n

Which of the following is a characteristic\n

Pause the video now to select the best answer.

Okay, the answer is B, all links between switches\nare layer 3.

This means that spanning tree is not needed,\n

there is no risk of layer 2 loops.

Okay, let’s go to question 4.

Which protocol is used to create virtual tunnels\n

Pause the video now to select the best answer.

Okay, the answer is D, VXLAN.

It is used to create virtual tunnels in the\noverlay network.

And although we didn’t cover any details\n

extensible LAN’ is very important.

It means that VXLAN supports many different\n

Okay, let’s go to question 5.

Which of the following are valid switch roles\n

(select three) Pause the video now to select\nthe best answers.

Okay, the answers areA, C, and D. Control,\n

These are the three different switch roles\n

Now let’s take a look at a bonus question \n