Toward optimal routing of lightpaths in dynamic WDM networks

This paper provides an approximate optimal routing algorithm, called relax-converter-first (RCF), for dynamic WDM networks with heterogeneous and partial wavelength conversion capability in each node. The algorithm can derive an optimal solution if the cost of consuming a wavelength converter is set much smaller than is the case for taking a wavelength channel. We propose a wavelength graph technique along with a modified Dijkstra´s shortest path first algorithm. Simulation is conducted to verify the performance in terms of blocking probability focusing on the following two themes: first, a comparison in performance is conducted among the cases of using fixed alternate routing, shortest path first algorithm with wavelength graph (SPAWG), and RCF; second, the performance of using the RCF scheme is examined with different cost of taking a wavelength converter in network nodes with different wavelength conversion capability. We also provide the simulation statistics about the optimality in using the RCF scheme under different network environments.