VRF Configuration For some very basic VRF configuration follow the steps:
Figure 1 Basic
VRF Configuration
1. Enters VRF configuration mode and assigns a VRF name. Router(config)#ip vrf vrf-name 2. Creates a VPN route distinguisher (RD) following one of the 16bit-ASN:32bit-number or 32bitIP:16bit-number explained above Router(config-vrf)#rd route-distinguisher 3. Creates a list of import and/or export route target communities for the specified VRF. Router(config-vrf)# route-target {import | export | both} route-distinguisher 4. (Optional step) Associates the specified route map with the VRF. Router(config-vrf)# import map route-map 5. Specifies an interface and enters interface configuration mode. Router(config)# interface type number
VRF Configuration 6. Associates a VRF with an interface or subinterface. Router(config-vrf)# ip vrf forwarding vrf-name To check your configuration, you can use ping or traceroute tools under Cisco CLI, but remember that you have to use “vrf vrf-name� parameter: Router# ping vrf vrf-name IP-address Also you can check the virtual routing table: Router# show ip route vrf vrf-name (Note: The RD / RT is a 8-byte (64-bits) number which can be written down as follow: - 16-bit AS number: your 32-bit number (e.g.) 65000:100 or -32-bit IP address: your 16-bit number (e.g) 192.168.0.1:10)
VRF Configuration Example
Figure 2 Topology
R1>enable R1#config t R1(config)#ip vrf R2 R1(config)#rd 2:2 R1(config)#ip vrf R3 R1(config)#rd 3:3 R1(config)#ip vrf R4 R1(config)#rd 4:4 R1(config)#ip vrf R5 R1(config)#rd 5:5 R1(config)#interface f0/0 R1(config-if)#ip vrf forwarding R2
VRF Configuration R1(config)#ip vrf forwarding R2 R1(config)#ip address 192.168.1.1 255.255.255.252 R1(config-if)#interface f0/1 R1(config-if)#ip vrf forwarding R3 R1(config-if)#ip address 192.168.1.1 255.255.255.252 R1(config-if)#no shutdown
R1(config)#interface f1/0 R1(config-if)#no switchport R1(config-if)#ip vrf forwarding R4 R1(config-if)#ip address 192.168.1.1 255.255.255.252 R1(config-if)#no shutdown R1(config)#interface f1/1 R1(config-if)#no switchport R1(config-if)#ip vrf forwarding R5 R1(config-if)#ip address 192.168.1.1 255.255.255.252 R1(config-if)#no shutdown For R2, R3, R4, R5 – Just configure the ip address and you are done . :) R2(config)#interface FastEthernet0/0 R2(config)#ip address 192.168.1.2 255.255.255.252 R2(config)#no shutdown (Note: IP address on all routers interfaces on Company End i.e. R2, R3, R4, R5 remain same.) Now try to ping R1 or PE from all CE routers, it should give successful reply. R2#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: !!!!! Now, we will going to check vrf route using below command R1#show ip route vrf R2 Routing Table: R2 Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2
VRF Configuration i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route Gateway of last resort is not set 192.168.1.0/30 is subnetted, 1 subnets C 192.168.1.0 is directly connected, FastEthernet0/0