Efficient algorithm for virtual topology design in multihop lightwave networks

One of the major challenges in the virtual topology design of a WDM star based system, is to incorporate in the optimization process both realistic objective functions and real system behavior. The authors present an efficient discrete optimization algorithm that meets these goals while incorporating the prevailing traffic conditions. They simulate the real system and then approximate the objective function by a short term simulation. The optimization process is based on an ordinal optimization approach, i.e., is insensitive to the approximation of the objective function obtained by short term simulation. Another crucial issue in virtual topology design is how to evaluate the quality of the solution obtained by the algorithm. They propose a new metric to evaluate the solution quality, the so called suboptimal quality, obtained by deriving the solution´s relative position in the state space according to the performance order. The experiments presented in the paper attest to the quality (efficiency and robustness) of the optimization algorithm and its suitability to solve the wavelength assignment problem