IMPLEMENTING VRF - LITE

Part 1: Build the Network and Configure Basic Device Settings.

Configure all the Routers with the hostnames and IP address configurations as mentioned in the topology.

Part 2: Configure and Verify VRF and Interface Addressing

Enable VRF on R1.

R1(config)#ip vrf a

R1(config-vrf)#ip vrf b

R1(config-vrf)exit

Bind the interfaces of R1 to the respective VRF

R1(config)#interface gi 0/2

R1(config-if)#ip vrf forwarding a

R1(config-if)#ip address 11.11.11.1 255.255.255.0

R1(config-if)#no shutdown

R1(config-if)#exit

R1(config-if)#interface gi 0/1

R1(config-if)#ip vrf forwarding b

R1(config-if)#ip address 11.11.11.1 255.255.255.0

R1(config-if)#no shutdown

Now, let’s configure R2.

R2(config)#interface gi 0/1

R2(config-if)#ip vrf forwarding a

R2(config-if)#ip address 22.22.22.1 255.255.255.0

R2(config-if)#no shutdown

R2(config-if)#exit

R2(config-if)#interface gi 0/2

R2(config-if)#ip vrf forwarding b

R2(config-if)#ip address 22.22.22.1 255.255.255.0

R2(config-if)#no shutdown

Now, we will bring up the connectivity between R1 and R2 for which you can either add one physical link per VRF or you can create some sub-interfaces to make the communication possible. Here I am using sub-interfaces.

R1(config)#interface gi 0/0

R1(config-if)#no shutdown

R1(config-if)#exit

R1(config-if)#interface gi 0/0.1

R1(config-subif)#ip vrf forwarding a

R1(config-subif)#encapsulation dot1q 2

R1(config-subif)#ip address 12.10.1.1 255.255.255.252

R1(config-subif)#interface gi 0/0.2

R1(config-subif)#ip vrf forwarding b

R1(config-subif)#encapsulation dot1q 3

R1(config-subif)#ip address 12.10.1.1 255.255.255.252

R1(config-subif)#exit

Let’s configure R2 now.

R2(config)#interface gi 0/0

R2(config-if)#no shutdown

R2(config-if)#exit

R2(config-if)#interface gi 0/0.1

R2(config-subif)#ip vrf forwarding a

R2(config-subif)#encapsulation dot1q 2

R2(config-subif)#ip address 12.10.1.2 255.255.255.252

R2(config-subif)#interface gi 0/0.2

R2(config-subif)#ip vrf forwarding b

R2(config-subif)#encapsulation dot1q 3

R2(config-subif)#ip address 12.10.1.2 255.255.255.252

R2(config-subif)#exit

Now let’s configure OSPF to make both the sites of Customer A and Customer B communicate with each other. Let’s begin with R3

For Customer A:

R3

R3(config)router ospf 10

R3(config-router)network 11.11.11.0 0.0.0.255 area 1

R3(config-router)exit

R5

R5(config)router ospf 10

R5(config-router)network 22.22.22.0 0.0.0.255 area 1

R5(config-router)exit

R1

R1(config)router ospf 10 vrf a

R1(config-router)network 12.10.1.0 0.0.0.3 area 1

R1(config-router)network 11.11.11.0 0.0.0.255 area 1

R1(config-router)exit

R2

R2(config)router ospf 10 vrf a

R2(config-router)network 12.10.1.0 0.0.0.3 area 1

R2(config-router)network 22.22.22.0 0.0.0.255 area 1

R2(config-router)exit

Verify connectivity by pinging R5 from R3 and vice versa. If you wish to ping from R1 there you will have to specify the source as VRF A by using the command ping vrf a 22.22.22.2

For Customer B:

R4

R3(config)router ospf 20

R3(config-router)network 11.11.11.0 0.0.0.255 area 2

R3(config-router)exit

R5

R5(config)router ospf 20

R5(config-router)network 22.22.22.0 0.0.0.255 area 2

R5(config-router)exit

R1

R1(config)router ospf 20 vrf b

R1(config-router)network 12.10.1.0 0.0.0.3 area 2

R1(config-router)network 11.11.11.0 0.0.0.255 area 2

R1(config-router)exit

R2

R2(config)router ospf 20 vrf b

R2(config-router)network 12.10.1.0 0.0.0.3 area 2

R2(config-router)network 22.22.22.0 0.0.0.255 area 2

R2(config-router)exit