Scalable VPN Routing Via Relaying
Enterprise customers are increasingly adopting MPLS (Multiprotocol Label Switching) VPN (Virtual Private Network) service that offers direct any-to-any reachability among the customer sites via a provider network. Unfortunately this direct reachability model makes the service provider's routing tables grow very large as the number of VPNs and the number of routes per customer increase. As a result, router memory in the provider's network has become a key bottleneck in provisioning new customers. This paper proposes Relaying, a scalable VPN routing architecture that the provider can implement simply by modifying the configuration of routers in the provider network, without requiring changes to the router hardware and software.