Interprovider VPNs—Configure Multihop MP-EBGP

In this type of interprovider VPN configuration, provider routers do not need to know all the routes in all the VPNs. Only the PE routers must have all the VPN routes. The provider routers simply forward traffic to the PE routers—they are not aware of the packets' destination. The connections between the AS border routers in separate ASs forward traffic between the ASs, much as a label-switched path (LSP) works.

The following are the basic steps you take to configure an interprovider VPN in this manner:

1. Configure multihop EBGP redistribution of labeled VPN-IPv4 routes between the source and destination ASs.
2. Configure EBGP to redistribute labeled IPv4 routes from its AS to neighboring ASs.
3. Configure MPLS on the end-PE routers of the VPNs.