Enhancing network availability by deflection based fast rerouting

With the emergence of voice over IP and other realtime business applications, there is a growing demand for high network availability. Commonly deployed link state routing protocols such as OSPF react to link failures through global (i.e., network wide) link state advertisements and routing table recomputations, causing significant forwarding discontinuity after a failure. To improve network availability without jeopardizing routing stability, we propose a proactive local rerouting based approach. The proposed approach prepares for failures using deflection routing and upon a failure, suppresses the link state advertisement and instead triggers local rerouting using an alternate table. Both node and link failure can be handled when no more than one component failure occurs and the proposed approach always finds a loop-free path to a destination if one such path exists. The experimental results show that the proposed approach achieves excellent performance.