Analysis of backup route reoptimization algorithms for optical shared mesh networks

In an optical mesh network operation, lightpaths are setup when requested, without prior knowledge of future requests. The concerns of increasing the sharing of backup paths and reducing capacity consumption are addressed on a best-of-now basis. As the number of lightpaths increases, it is possible to reroute existing paths to increase sharing further and free up more network capacity. This paper proposes several rerouting algorithms and compares their performance on test networks. All the described algorithms reroute the backup paths only and do not affect ongoing service. Also, the effect of network load factor and the number of lightpaths on the rerouting gain is examined.