RWA in WDM Rings: An Efficient Formulation Based on Maximal Independent Set Decomposition
WDM rings are now capable of supporting more than 100 wavelengths over a single fiber. Conventional link and path formulations for the RWA problem are inefficient due to the inherent symmetry in wavelength assignment and the fact that the problem size increases fast with the number of wavelengths. Although a formulation based on Maximal Independent Sets (MIS) does not have these drawbacks, it suffers from the exponential growth in the number of variables with the increasing network size. The authors develop a new ILP formulation based on the idea of partitioning the path set and representing the maximal independent sets in the original network using the independent sets calculated in each of these partitions.