Link-Disjoint Shortest-Delay Path-Pair Computation Algorithms for Shared Mesh Restoration Networks

We present two novel double-constrained routing algorithms, called: Two-step Delay-constrained Pool Sharing (TDPS) and One-step Delay-constrained Pool Sharing (ODPS), in a survivable mesh network. The goal of both algorithms is to compute a pair of link-disjoint primary and backup paths between a given source and destination nodes, which guarantees full recovery from any single link failure in the network. Our objective is to minimize simultaneously the total end-to-end delay time along the primary and backup paths and the resources (such as backup bandwidth) used in the network. Using simulation, we have studied both TDPS and ODPS algorithms on three existing North-American transport networks. We show that the ODPS scheme eliminates the trap-topology problem associated with many two-step link-disjoint path computation algorithms proposed in the literature. It also outperforms TDPS in terms of the total end-to-end delay along the working and backup paths.