Grooming of Multicast Sessions in WDM Mesh Networks ∗

Handling “sub-wavelength” traffic demands by costeffective traffic grooming in WDM networks has become prominent. We, in this paper, address the problem of routing and wavelength assignment of multicast sessions with sub-wavelength traffic demands in the scenario of WDM mesh networks. In order to support multicasting, individual nodes need to have the capability of duplicating traffic. We propose a node architecture which will perform the task of duplication in the optical as well as the electronic domain. This architecture is cost effective as it allows the duplication in optical domain also. The traffic duplication at the electronic level is much more expensive than the optical level. We study the problem of assigning routes and wavelengths to the multicast sessions so as to minimize the electronic copying resources required. We present a non-linear programming (NLP) formulation as an analytical model for the problem. As solving the model for large networks is intractable, we propose the heuristic algorithms namely (kSPT, GRS, and GCOT). We have studied the performance of the proposed heuristic algorithms by conducting extensive simulation experiments.