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VPRN (L3VPN) Inter-AS Model C — Nokia 7750 and Cisco XR on GNS3
Introduction
In my previous article, I showed how to setup layer 3 VPRN (or L3VPN) among Nokia 7750 and Cisco 7200 routers so that different IP subnets (e.g., PCs) served by a carrier’s IP/MPLS network can communicate. In fact, the carrier’s IP/MPLS network is shared by many different customers offering them with various L2 and L3 network services and each customer thought that they had their own private WAN network (i.e., VPN). The control plane of the VPRN PEs uses Multi-Protocol Internal Border Gateway Protocol (MP-iBGP) with vpn-ipv4 and/or vpn-ipv6 address families to exchange customers’ VPN routes, route targets (i.e., VPN memberships), and route distinguishers etc… over the carrier’s shared IP/MPLS network. MP-iBGP is used as all the PEs are in the same Autonomous System (AS) and thus there is no concern about sharing networking topology information among the PEs.
If a customer has international offices that are beyond the service coverage of the local carrier, carriers in different locations/countries are needed to work together (i.e., inter-AS VPRN) in order to provide seamless VPRN service to the customer’s local and international offices. The inter-AS VPRN solutions need to limit or eliminate any unnecessary network information exchange among the carriers for security reason. Also, the…
