Lab: Configuring an MPLS VPN 247

line aux 0 line vty 0 4

privilege level 15 password lab logging synchronous login

ip netmask-format decimal

!

end

Verification with Ping

To verify that the VPN works, all you need to do is a ping from one peer to the other. The following output is the result of a ping from Peer 2 to Peer 1:

Peer2#ping 192.168.1.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.1.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 116/119/120 ms

Routing Table Isolation

First of all, let’s talk about routing table isolation and its implications. On the Raleigh and Atlanta POP routers, no customer (Peer 1 and Peer 2) routes show up in the global routing table. The routing tables of the Atlanta and Raleigh POP routers are as follows:

Raleigh#show ip route

.

. Output Omitted

.

Gateway of last resort is not set

204.134.83.0 255.255.255.0 is variably subnetted, 5 subnets, 2 masks

248 Chapter 6 MPLS VPNs and RIP

C 204.134.83.8 255.255.255.252 is directly connected, Serial0/3

R204.134.83.1 255.255.255.255

[120/2] via 204.134.83.9, 00:00:00, Serial0/3 C 204.134.83.3 255.255.255.255 is directly

connected, Loopback0

R204.134.83.2 255.255.255.255

[120/1] via 204.134.83.9, 00:00:00, Serial0/3

R204.134.83.4 255.255.255.252

[120/1] via 204.134.83.9, 00:00:00, Serial0/3

Atlanta#show ip route

.

. Output Omitted

.

Gateway of last resort is not set

204.134.83.0 255.255.255.0 is variably subnetted, 5 subnets, 2 masks

R204.134.83.8 255.255.255.252

[120/1] via 204.134.83.6, 00:00:07, Serial0/0 C 204.134.83.1 255.255.255.255 is directly

connected, Loopback0

R204.134.83.3 255.255.255.255

[120/2] via 204.134.83.6, 00:00:07, Serial0/0

R204.134.83.2 255.255.255.255

[120/1] via 204.134.83.6, 00:00:07, Serial0/0 C 204.134.83.4 255.255.255.252 is directly

connected,

In addition, none of the customer routes (Peer 1 and Peer 2) show up on the Core router. The Core router is only running the IGP (RIPv2) and knows nothing about any of the customer subnets, as you can see in the global routing table of the Core router:

Core#show ip route

.

. Output Omitted

.

R204.134.83.1 255.255.255.255

[120/1] via 204.134.83.5, 00:00:19, Serial0/1

R204.134.83.3 255.255.255.255

[120/1] via 204.134.83.10, 00:00:26, Serial0/0

C204.134.83.2 255.255.255.255 is directly connected, Loopback0

C204.134.83.4 255.255.255.252 is directly connected, Serial0/1

If you see any customer routes in the global routing table, then more than likely, redistribution has been misconfigured. You need to check the redistribution syntax on your PE routers to make sure that they have the proper configuration.

What about on the client routers? They are isolated as well. The client routers do not know any of the details of the service provider network. If you recall, RIPv2 is running as the IGP for the service provider network. RIPv2 is also running on the clients (Peer 1 and Peer 2). The routing tables of the Peer 1 and Peer 2 routers are shown in the following device output. Notice that no service provider routes are in the global routing tables for Peer 1 and Peer 2:

Peer1#show ip route

.

. Output Omitted

.

Gateway of last resort is not set

192.168.1.0 255.255.255.255 is subnetted, 1 subnets C 192.168.1.1 is directly connected, Loopback0

192.168.3.0 255.255.255.252 is subnetted, 2 subnets R 192.168.3.8 [120/1] via 192.168.3.6, 00:00:12,

Serial0

250 Chapter 6 MPLS VPNs and RIP

C192.168.3.4 is directly connected, Serial0

Peer2#show ip route

.

. Output Omitted

.

Gateway of last resort is not set

R 192.168.1.0 255.255.255.0 [120/2] via 192.168.3.9, 00:00:04, Serial0

192.168.2.0 255.255.255.255 is subnetted, 1 subnets

C192.168.2.1 is directly connected, Loopback0 192.168.3.0 255.255.255.252 is subnetted, 2 subnets

C192.168.3.8 is directly connected, Serial0

R 192.168.3.4 [120/1] via 192.168.3.9, 00:00:05,

Serial0

Verifying VRF Routes

In learning about MPLS VPNs, it’s important that you understand the flow of routing information. Let’s begin this discussion by looking at the routing table of vpn_1 as it exists on the Atlanta POP router:

Atlanta#show ip route vrf vpn_1

.

. Output Omitted

.

Gateway of last resort is not set

R 192.168.1.0 255.255.255.0 [120/1] via 192.168.3.5, 00:00:08, Serial0/1

B192.168.2.0 255.255.255.0 [200/1] via 204.134.83.3, 00:01:22

192.168.3.0 255.255.255.252 is subnetted, 2 subnets

B192.168.3.8 [200/0] via 204.134.83.3, 00:06:07 C 192.168.3.4 is directly connected, Serial0/1

In the routing table for vpn_1 on the Atlanta POP router, there are BGP routes (indicated by B in the routing table output) and RIPv2 routes (indicated