Non-Uniform Waveband Switching in Multi-Granular Optical Networks

Waveband switching (WBS) has recently attracted attention from a wide range of industry and academia groups for its practical and hierarchial concepts in handling massive lightpaths with reduced control complexity and nodal size. Previous studies demonstrate that non-uniform waveband switching, in which wavebands contain various number of wavelengths, can provide more flexibility for wavelength grouping thus achieving more port saving. In this work, for the first time, we model the non-uniform waveband switching problem in a mesh topology with static off-line traffic, by using Integer Liner Programming (ILP) formulations. As an optimal approach, the proposed ILP model takes routing, wavelength grouping, traffic demands and non-uniform band settings into consideration. In the cases that the optimal ILP becomes intractable, we develop an efficient heuristic called simulated non-uniform waveband assignment (SNWS). Our simulations and analysis show that the proposed heuristic SNWS can achieve smaller port count than the existing near-optimal uniform waveband switching scheme.