Segment routing single link failure congestion optimization

Abstract

Segment routing is an implementation of the source routing paradigm built over an Interior Gateway Protocol. It allows improving Traffic Engineering in IP/MPLS networks by decomposing forwarding paths in lists of smaller paths called segments. The flexibility introduced by segment routing enables new responsive and dynamic methods to react to network fault events, such as link failures. Typical responses to single link failures only aim to reestablish loop-free connectivity between affected routers and do not account for impacts in network congestion. As Interior Gateway Protocols recompute shortest-paths after a link failure, SR paths and links utilization are affected by the fault augmenting the overall network congestion. This paper addresses this problem comparing post-convergence network congestion values obtained with industry and new proposal Evolutionary Computation based recovery path computation methods for segment routing. Furthermore, by comparing and analyzing each method's advantages and disadvantages, we show that a multiplane optimization procedure stands out with best results.