Scalable optimal traffic grooming in WDM rings incorporating fast RWA formulation

We present a scalable formulation for the traffic grooming problem in WDM ring networks. Specifically, we modify the ILP formulation to replace the constraints related to routing and wavelength assignment (RWA), typically based on a link approach, with a new set of constraints based on the maximal independent set decomposition (MISD) that we recently developed to solve optimally the RWA problem in ring networks. Our experimental study indicates that the new formulation results in an improvement of up to two orders of magnitude in running time. Consequently, it is now possible to solve the traffic grooming problem to optimality for 16-node rings in a few seconds using commodity hardware.