Routing and wavelength assignment in WDM rings with heterogeneous wavelength conversion capabilities

In this paper, we study the routing and wavelength assignment (RWA) tasks in WDM rings with heterogeneous wavelength conversion capabilities. By heterogeneous, we mean that different nodes of the WDM ring might have different wavelength conversion capabilities. An integer linear programming (ILP) formulation is used to optimally solve small examples of the problem. Because many RWA problems have exponential complexity, efficient heuristics are needed. We use the results from the ILP to evaluate the performance of several fast RWA algorithms, which are shown to give accurate solutions under various traffic scenarios.