Abstract: A new algorithm is proposed to quickly optimize WDM networks with path protecting p cycles. A heuristic method is considered to search the Mutually Disjoint Path Group (MDPG) set for each candidate p cycle. An Integer Linear Programming (ILP) model is introduced to design WDM networks with MDPG. Numerical studies show that the optimal results obtained with the MDPG ILP algorithm are all very close to the solutions of pure ILP method but with greatly reduced computational time for different network topologies. The optimization procedure tends to choose p cycles protecting connections that are completely straddling p cycles.

Key words: WDM, path protecting, p cycles, ILP