WDM network design by ILP models based on flow aggregation

Planning and optimization of WDM networks has raised much interest among the research community in the last years. Integer Linear Programming (ILP) is the most used exact method to perform this task and many studies have been published concerning this issue. Unfortunately, many works have shown that, even for small networks, the ILP formulations can easily overwhelm the capabilities of today state-of-the-art computing facilities. So in this paper we focus our attention on ILP model computational efficiency in order to provide a more effective tool in view of direct planning or other benchmarking applications. Our formulation exploits flow aggregation and consists in a new ILP formulation that allows us to reach optimal solutions with less computational effort compared to other ILP approaches. This formulation applies to multifiber mesh networks with or without wavelength conversion. After presenting the formulation we discuss the results obtained in the optimization of case-study networks.