Example: Full-Mesh VPNs

In a fully meshed VPN, each site in the VPN can reach every other site in the VPN. Figure 90 illustrates a situation with two fully meshed VPNs, VPN A and VPN B. VPN A includes Customer Sites 1, 3, and 5 through VRFs A, C, and E. VPN B includes Customer Sites 2, 4, and 6 through VRFs B, D, and F.

Figure 90: Fully Meshed VPNs

BGP sessions exist between PE 1 and PE 2, PE 2 and PE 3, and PE 3 and PE 1. The MPLS paths through the service provider core are omitted for clarity.

To configure route targets for this fully meshed scenario, you specify the same route target for the import list and export list on all VRFs in VPN A. The VRFs in VPN B use a different route target, but it is the same for the import list and export list for all.

Route-target configuration on PE 1:

host1(config)#virtual-router newyork host1:newyork(config)#ip vrf vrfA host1:newyork(config-vrf)#route-target both 777:1 host1:newyork(config-vrf)#exit host1:newyork(config)#ip vrf vrfB host1:newyork(config-vrf)#route-target both 777:2

Route-target configuration on PE 2:

host2(config)#virtual-router boston host2:boston(config)#ip vrf vrfC host2:boston(config-vrf)#route-target both 777:1 host2:boston(config-vrf)#exit host2:boston(config)#ip vrf vrfD host2:boston(config-vrf)#route-target both 777:2

Route-target configuration on PE 3:

host3(config)#ip vrf vrfE host3(config-vrf)#route-target both 777:1 host3(config-vrf)#exit host3(config)#ip vrf vrfF host3(config-vrf)#route-target both 777:2