Improved method for guaranteed shared protection in WDM optical networks

Previous dynamic resource allocation method (Separate Path Selection, SPS) for survivable networks, 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-SPS. Instead of rejecting an arrival call immediately when a backup lightpath for the optimal primary lightpath cannot be found, M-SPS continue to try the sub-optimal one until a legal primary-backup pair can be selected. We apply M-SPS to CERNET(-)Like and NSFNET networks. Simulation results show that M-SPS improves the network performance remarkably.