Routing connections with differentiated reliability in mesh WDM networks

Survivability has emerged as the most important issue in the design of the 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. This 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 1) firstly derives a shortest path, by using a shortest path algorithm such as Dijkstra's algorithm, as working path and followed by 2) derives an optimal backup path for the working path such that the working/backup path pair can meets the required reliability while consumes as less 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.