Design techniques of two-layer architectures for WDM optical networks

A general method for designing multilayered WDM optical networks, based on the combined use of single- and multi-hop connection modes, is presented. It takes into account variable values for the number of users and wavelengths in each cluster. Closed form expressions are derived for the transmission capacity and the optimum number of channels for intra-cluster communications, either in the case of uniform or non-uniform traffic distribution. The analytical approach is particularly useful in the presence of constraints on the number of wavelengths, due to technological limits or non-linear phenomena, when sub-optimal solutions must be necessarily addressed. The proposed method is integrated with the adoption of well-known selection procedures, like simulated annealing or genetic algorithms, to reduce the computational effort.