Dynamic lightpath protection in WDM mesh networks under risk-disjoint constraint

Path protection requires finding a working path and a protection path that are link disjoint. We consider the dynamic lightpath protection problem in WDM mesh networks where a single risk factor may cause multiple links to fail simultaneously. The objective is to find link-disjoint lightpaths that are also risk disjoint. A similar problem has recently been proven to be NP-complete. We give an alternative proof of the NP-completeness, and formulate the problem as an integer linear program. We then develop heuristic algorithms and evaluate the performance of the algorithms through computer simulation. We show that we can achieve satisfactory performance using the heuristic techniques.