Optimal nonuniform wavebanding in WDM mesh networks

Grouping together a set of consecutive wavelengths in a WDM network and switching them together as a single waveband could achieve savings in switching costs of an optical cross-connect. This technique is known as waveband switching. While previous work has focused on either uniform band sizes or nonuniform band sizes considering a single node or ring networks, in this paper we focus on optimizing the number of wavebands and their sizes for mesh topologies. We formulate a problem of optimizing the number of wavebands in a mesh network for a given set of lightpaths. The objective of the band minimization problem is to minimize the number of nonuniform wavebands in the network while satisfying the traffic requests. We formulate an integer linear program and propose efficient heuristics. Simulation results are presented to demonstrate the effectiveness of the proposed approaches under static traffic case. Our results show that the number of switching elements can be reduced by a large amount using waveband switching compared to wavelength switching. We also apply the proposed waveband strategy to the dynamic stochastic traffic case and evaluate the network performance in terms of blocking probability through numerical simulations.