A new intentional lightpath rerouting scheme for dynamic traffic in WDM all-optical networks

One limitation of a WDM all-optical network is the wavelength continuity constraint imposed by the all-optical cross-connect switches which do not allow a circuit to be placed on a non wavelength-continuous route. This constraint leads to inefficient utilization of wavelength channels and results in higher blocking probability. Rerouting is an effective approach that can increase the efficiency. In this paper, we employ intentional rerouting approach to improve the network utilization efficiency under dynamic traffic model. Intentional lightpath rerouting is to intentionally reroute already established lightpaths during their life period without affecting other existing lightpaths, so as to achieve a better blocking performance. The proposed intentional rerouting algorithm, namely, Intentional Move To Vacant Shorter Path (I-MTVSP) initiates the rerouting procedure when a connection leaves and its lightpath is hence released. Already established lightpaths that can be set up on a new vacant shorter path are selected to be rerouted. An existing lightpath can be rerouted only once during its life period, so as to reduce the service disruption period due to rerouting. Simulation results show that our proposed intentional lightpath rerouting algorithm improves significantly the rejection ratio when keeping a short service disruption period.