Achieving Network Efficient Stateful Anycast Communications

Abstract

Using IP anycast, connectionless services such as DNS can be decentralized to cope with high service request rates. Unfortunately, most Internet services cannot take direct advantage of anycast addressing because they rely on stateful communications. Subsequent packets of the same session may be routed to a different anycast group member, resulting in a broken service. Therefore, we introduce a transparent layer-3 architecture that provides anycast support for stateful services.

Taking into account user demands, available resources, extra network overhead and anycast infrastructure costs, we address optimal proxy router placement and infrastructure dimensioning, an issue that has not been tackled before for similar architectures. Simulation results indicate that even modest overlay infrastructures, consisting of a small number of proxy routers, often result in an effective stateful anycast solution where the detour via the proxy routers is negligible.