Multiple abstraction schemes for generalized virtual private switched networks

An IP-VPN overlay over traditional L1/L2 transport networks has serious problems with scaling, not only with respect to routing but also the time it takes to provision these services. GVPN is a service that uses GMPLS as the common control plane to address these issues with features like client initiated signaling and auto-discovery. It allows routing over the access links, eliminating the O(nß2) client routing adjacency issue. In today´s deployment, routing enables exchange of reachability information, which is not very useful for dynamic edge nodes requiring services on demand. Also a major obstacle to exploiting routing to its full potential is the provider´s reluctance to expose the internals of the core network. In this piece, we try to explore the idea of enabling traffic-engineering capability to the edge routers using the concept of topology abstraction, which involves no preset resources. The study shows the different forms of abstractions that are possible with their pros and cons. We end our discussion prototyping two different abstraction schemes discussed in this article using a real lab setup. Our discussion for the most part is generic and could be applied to any L1 or L2 switched transport networks.