A genetic algorithm for solving virtual topology configuration transition problem in WDM network

Wavelength-division multiplexing (WDM) technology has emerged as a promising technology for backbone networks. The set of all-optical communication channels (lightpaths) in the optical layer defines the virtual topology for the upper layer applications. Since the traffic demand of upper layer applications fluctuates from time to time, it is required to reconfigure the underlying virtual topology in the optical layer accordingly. However, the reconfiguration for the virtual topology is reluctantly disruptive to the network since some lightpaths should be torn down and some traffic has to be buffered or rerouted during the reconfiguration process. Therefore, it needs to have an efficient transition method to shift the current virtual topology to the new one so as to minimize the effect of the reconfiguration on the upper layer traffic. In this paper, the WDM virtual topology configuration transition problem (WVTCTP) which minimizes the average weighted hop distance is studied. Since the WVTCTP is NP-hard, a genetic algorithm (GA) is proposed to solve it. Simulated results show that the proposed GA can get better performance than heuristic, simulated annealing, and iterative improving methods.