Virtual topology reconfiguration in hierarchical cross-connect WDM networks

Multigranularity optical cross-connects (MG-OXCs) have emerged as the means to save the cost of manufacturing large optical cross-connects (OXCs) used in the IP-over-WDM networks. This paper considers the virtual topology configuration problem in the MG-OXC networks that has not yet been studied. We assume that the future traffic pattern is known a priori and we are to reconfigure the original topology, without dramatically changing the current virtual topology, to the new one that is suitable for the new traffic pattern. We propose our heuristic preference based reconfiguration algorithm (PBRA) to solve the problem by constructing an auxiliary graph to help determining the addition, deletion, or keeping of the virtual links. Simulation results show that we can change less original virtual topology at the cost of small increase in blocking probability.