Routing connections with differentiated reliability in mesh WDM networks

Survivability has emerged as the most important issue in the design of high-speed modern communication networks. To deal with any unexpected interruption caused by failure events (such as fiber cuts), pre-planning a protection path with sufficient bandwidth for each working path has been widely accepted as the most effective solution. The paper addresses the problem of routing dynamic connections with reliability requirements across networks, by taking shared risk link group (SRLG) into consideration. The goal of the routing process is then to identify a working path, or if necessary, a working/backup path pair that meets the requested reliability for a connection. Since the problem is NP-hard, we propose a two-step approach which derives first a shortest path, by using a shortest path algorithm such as Dijkstra´s algorithm, as working path and then an optimal backup path for the working path such that the working/backup path pair can meet the required reliability while consuming as few resources as possible. However, the second step is also NP-hard. We thus devise a heuristic algorithm for the second step. Simulations are conducted to verify the performance of the proposed algorithm.