Lightpath rerouting for differentiated services in WDM all-optical networks

Lightpath rerouting is a viable and cost effective solution to improve the network throughput conditioned by the wavelength continuity constraint in all-optical networks. Two traffic classes have been considered referred to as scheduled lightpath demands (SLDs) and random lightpath demands (RLDs). SLDs correspond to high priority traffic whereas RLDs correspond to best effort traffic. An incoming lightpath demand (LD) is rejected when no path-free wavelengths are left in the network to accommodate it. It may happen that by rerouting a certain number of already established LDs, the incoming connection can be set up. In this paper, we propose a new lightpath rerouting algorithm minimizing the amount of rerouted WDM channels. SLD rerouting is forbidden while the establishment of a new RLD may require the rerouting of one or several RLDs. Simulation results show that our algorithm improves the rejection ratio and is less CPU time consuming than rerouting algorithms previously presented in the literature.