Insights for segment protection in survivable WDM mesh networks with SRLG constraints

Segment protection has been recognized as an efficient way to avoid "traps" in survivable WDM mesh network. In this article, we present some insights on this kind of protection. We first prove the correctness of segment protection used for avoiding traps. We then investigate the effect of the number of segments on the blocking performance in several typical real networks (includes middle and large networks). We find that, in most cases, it is sufficient to use two backup segments to protect a given active path. Based on this observation, we then propose a novel and efficient segment protection algorithm, called two-segment (TS), which has a lower-computational complexity and comparative performance than existing algorithms.