Distributed Traffic Adaptive Wavelength Routing in IP-Over-WDM networks

In wavelength routed wavelength division multiplexing (WR-WDM) networks, a set of lightpaths (all-optical communication paths) defines the virtual topology. Internet protocol (IP) makes use of virtual topology to route its traffic in the optical form. The virtual topology is designed with an aim of minimizing certain objective function value. In the event of changes in traffic demand at the IP layer, the objective function value of the network (virtual topology) may be affected leading to decreased network performance. Thus, the underlying virtual topology needs to be changed in response to the changing traffic patterns in the IP layer. This process of changing the virtual topology to meet the traffic requirement is called as reconfiguration. As distributed networks like IP over WDM networks demand a fully distributed process for reconfiguration, we view the reconfiguration as an on-line distributed process that provides a trade-off between the objective function value and the number of changes committed to the virtual topology. The objective function value decides how best the topology is suited for the given traffic demand. The number of changes decides the extent of traffic disruption in the network while making a transition to the new virtual topology. The performance of the proposed methodology is studied through extensive simulation experiments in terms of objective function value of reconfigured topology and the number of changes performed to get the reconfigured topology.