On survivable traffic grooming over logical topologies in WDM mesh networks

Component failure in a WDM network is a serious problem that has attracted considerable attention in recent times. In a standard protection (or restoration) scheme the objective is to preserve the logical topology by switching over to back-up paths (or by setting up new lightpaths) after a fault occurs. In this paper we have proposed a new scheme where we handle a fault simply by modifying the traffic routing scheme to avoid the fault. We show that it is possible to guarantee that a significantly high number of requests for communication can be handled using this scheme, irrespective of the location of the fault. Two new integer linear program formulations have been presented using this approach. The first formulation assumes a fixed RWA, while the second finds the optimal RWA for maximizing guaranteed throughput. A large number simulation experiments demonstrate that, in the vast majority of cases, an optimal solution obtained using our second formulation not only generates a survivable routing but handles all the requests that the original fault-free logical topology was designed to handle.