All language subtitles for Free-CCNA-VRF-Day-54-part-3-CCNA-200-301-Complete-Course_en

This is a complete course for the CCNA.

In this video we will cover Virtual Routing\nand Forwarding, VRF.

VRF allows us to divide one physical router\n

You can think of it like VLANs for routers.

VLANs divide a switch into multiple virtual\n

and VRF divides a router into multiple virtual\n

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

First I will introduce the concept of VRF\n

Note that VRF configuration isn’t actually\n

configurations will help you understand how\nit works.

Unfortunately VRF isn’t supported in Packet\n

you’ll need to use something like Cisco\n

The diagram at the bottom gives an idea of\nhow VRFs work.

The black box in the middle represents R1,\n

The blue, green, and red router icons inside\n

Let’s call them VRF1, VRF2, and VRF3.

So, Virtual Routing and Forwarding is used\n

This is similar to how VLANs are used to divide\n

By default, all interfaces on a switch are\n

When using VLANs, we can divide that one broadcast\n

Similarly, by default all router interfaces\n

By ‘routing domain’ I mean, by default\n

be forwarded out of any other interface on\n

For example, without using VRF, in the diagram\n

can be routed to and forwarded out of R1’s\nG1/2 interface.

However, with VRF that won’t be possible.

G0/0 is in VRF1 and G1/2 is in VRF3, so traffic\n

It does this allowing a router to build separate\nrouting tables.

Normally a router has one routing table, but\n

Interfaces, specifically layer 3 interfaces,\n

Keep in mind that VRF does not apply to Layer\n

Only router interfaces, SVIs, and routed ports\n

As I mentioned before, traffic in one VRF\n

However, as an exception VRF Leaking can be\n

That is a more advanced concept though and\n

So, what is the main purpose of VRF?

Well VRF is commonly used to facilitate MPLS,\n

However, that’s actually not the kind of\n

The kind of VRF we are talking about is VRF-lite,\n

So, keep in mind that when I say ‘VRF’\n

VRF is commonly used by service providers\n

Well, there are two main points.

First, each customer’s traffic is isolated\n

to their own virtual router within the service\n

In the diagram below, let’s say the blue,\n

All customers connect to the same service\n

a different virtual router, a different VRF\ninstance.

And another major point is that customer IP\n

For example, the blue customer uses subnets\n

The green customer also uses 192.168.1.0/24\nand 2.0/24.

Without VRF, this kind of configuration is\n

But with VRF, it works fine even though the\n

Okay, now let’s try configuring VRF to help\n

To demonstrate VRF configuration I’ll use\nthe network below.

SPR1 is a service provider router providing\n

C1R1 and C1R2 belong to Customer 1 and C2R1\n

Both Customer 1 and Customer 2 use subnet\n192.168.1.0/30.

First, let’s see what happens when we try\n

First I configured SPR1’s G0/0 and G0/1,\n

But when I try to configure G0/2, I get an\n

G0/2 cannot use IP address 192.168.1.1 because\n

In this case it’s the exact same IP address,\n

To prove that point I tried to configure it\n

Even if the IP address is different, G0/2\n

So, without the use of VRF, two interfaces\n

Next let’s use VRF to configure this network\nproperly.

First we have to create the VRFs, which can\n

IP VRF, followed by the VRF name.

Here I created two VRFs, one named CUSTOMER1\n

I then used the command SHOW IP VRF which\n

As you can see, the CUSTOMER1 and CUSTOMER2\nVRFs were created.

The next step is to assign interfaces to each\nVRF.

So, from interface config mode for G0/0 I\n

G0/0 is now part of the CUSTOMER1 VRF, however\n

Interface G0/0 IPv4 disabled and addresses\n

If an interface has an IP address configured,\n

So, I then re-configured the IP address, 192.168.1.1/30.

Again, the IP address I configured before\n

I then configured the G0/2 interface.

Note that this time it worked, I was able\n

That’s because they are in separate VRFs.

I then configured G0/3 as well.

I then once again confirmed the VRFs and now\n

So, SPR1 is now divided into two separate\n

includes G0/0 and G0/1, and the CUSTOMER2\n

So, basic configuration of VRF-lite is simple:\n

assign interfaces to VRFs with the IP VRF\nFORWARDING command.

There is of course a lot more depth to VRFs,\n

I then used SHOW IP ROUTE on SPR1, but I don’t\nsee any routes.

Usually you’d expect to see connected and\n

on interfaces, so why is nothing displayed\nhere?

SHOW IP ROUTE displays the ‘global routing\n

you’re used to when not using VRFs.

In this case, all of SPR1’s interfaces are\n

By the way, you can have a mix of interfaces\n

So, I then used the command SHOW IP ROUTE\n

the connected and local routes for G0/0 and\nG0/1.

So, if you want to see a VRF’s routing table\n

Here I viewed the CUSTOMER2 VRF’s routing\ntable.

So, these are separate routing tables from\n

By the way, if an interface is not in a VRF\n

table, and it will be isolated from the interfaces\n

VRFs are isolated from each other.

To test reachability, I tried some pings from\nSPR1.

I first pinged 192.168.1.2, but all the pings\nfailed.

It’s because, in the global routing table,\nthere are no routes.

As I showed in the previous slide, the global\n

You can specify the VRF when pinging like\n

Which device was SPR1 pinging in this case?

There are two devices with the IP address\n

SPR1 was pinging C1R1 because I specified\nthe CUSTOMER1 VRF.

In the CUSTOMER1 VRF again I pinged 192.168.11.2,\n

That’s because, in the CUSTOMER1 VRF’s\n

This time I pinged 192.168.1.2 and specified\nthe CUSTOMER2 VRF.

Who is SPR1 pinging this time?

C2R1, connected to G0/2 in the CUSTOMER2 VRF.

And I pinged 192.168.12.2, C2R2, which worked\n

So, to sum it up, hosts in the same VRF can\n

SPR1 was divided into two separate virtual\nrouters.

Here’s what we covered in this video.

I introduced VRFs and showed the basics of\n

But remember, what we mentioned in this video\n

which means we’re not using VRF with MPLS.

VRF is used to split a router up into multiple\n

Service providers can use VRFs to allow multiple\n

while still allowing their traffic to be isolated.

Plus, it doesn’t matter if customers use\n

each VRF is a separate routing table.

For the CCNA, it’s enough to just understand\n

to study at the CCNP level and beyond you’ll\n

Okay, let’s go to the quiz, here’s question\n1.

You issue the following commands on R1’s\nG0/0 interface.

However, after issuing show ip interface brief\n

Pause the video now to think about the answer.

Okay, the answer is B, the IP address was\n

As I showed earlier, if an interface already\n

removed when you assign it to a VRF.

You will then have to re-configure the IP\naddress.

So, if you’re planning to use VRFs you should\n

If you issue the command ping 192.168.1.10\n

Pause the video now to select the best answer.

Okay, the answer is D, no device will respond.

Actually, R1 won’t be able to even send\nthe pings.

All of R1’s interfaces are assigned to VRFs,\n

None of R1’s interfaces are using the global\n

be empty and it won’t be able to send the\npings.

Which of the following statements about VLANs\n

Pause the video now to select your answers.

Okay, the answers are C, D, and F. VRFs divide\n

In effect, you are dividing the router into\n

VLANs, on the other hand, divide switches\n

And router interfaces in different VRFs can\n

A is incorrect because VRFs do not create\n

Router interfaces are already in separate\n

B is wrong because VLANs do not create separate\n

the switch still keeps one MAC address table.

And E is wrong because VRFs can also be configured\n

switches, not just on routers.

Okay, that’s all for the quiz and this video.

I hope it was helpful, thanks for watching.