A Hybrid Protection/Restoration Scheme for Two-Link Failure in WDM Mesh Networks

We consider the problem of handling two-link failures in WDM mesh networks. Existing schemes either pre-reserve two backup paths for each demand or compute new backup paths for unprotected demands after the first link failure occurs. Both approaches require a large amount of backup capacity. In this paper, we propose a capacity efficient hybrid protection/restoration scheme for handling two-link failures. The protection component reserves backup capacity intelligently to ensure the majority of the affected demands can be restored using the pre-planned backup paths upon a two-link failure. For the rest of the affected demands, our restoration component dynamically finds new backup paths to quickly restore them. The capacity efficiency and protection/restoration capability of our hybrid scheme are demonstrated through numerical results.