An improved method for guaranteed shared protection in WDM optical networks

Previous dynamic resource allocation method (separate path selection, SPS) for a survivable network is always separated into two steps, that is, determine a primary path first and then select a backup path for the primary path. In this paper we analyze the drawback of the traditional SPS technique and propose an efficient shared protection method called M/spl I.bar/SPS. Instead of rejecting an arrival call immediately when a backup lightpath for the optimal primary lightpath cannot be found, M/spl I.bar/SPS continue to try the sub-optimal one until a legal primary-backup pair can be selected. We apply M/spl I.bar/SPS to CERNET/spl I.bar/Like and NSFNET networks. Simulation results show that M/spl I.bar/SPS improves the network performance remarkably.