Wavelength requirements for virtual topology reconfiguration in WDM ring networks

Through the use of configurable WDM technology including tunable optical transceivers and frequency selective switches, next generation WDM networks will allow multiple virtual topologies to be dynamically established on a given physical topology. We determine the number of wavelengths required to support all possible virtual topologies on a bidirectional ring physical topology. We first determine wavelength requirements for networks using shortest path routing. We then reduce network wavelength requirements by presenting novel adaptive lightpath routing and wavelength assignment strategies. We also show that this reduced wavelength requirement is optimal. These results are first derived for the single port per node case and then extended to networks with multiple ports per node