Connectivity and sparse wavelength conversion in wavelength-routing networks

Wavelength-routing networks offer the advantages of wavelength re-use and scalability over broadcast-and-select networks and are therefore suitable for wide area networks (WANs). We study the effects of topological connectivity and wavelength conversion in circuit-switched all-optical wavelength-routing networks. An approximate blocking analysis of such network is performed. We first propose an improved framework for the analysis of networks with arbitrary topology. We introduce a simple model for networks with a variable number of converters and analyze the effect of wavelength converter density on blocking probability. We then apply this framework to two sparse network topologies, the ring and the mesh-torus, and obtain the blocking performance. The results show that, in most cases, only a fraction of the network nodes need to be equipped with wavelength conversion capability for good performance. Finally, the tradeoff between physical connectivity, wavelength conversion, and the number of available wavelengths is studied through networks with random topologies