摘要: | Anycast refers to the transmission of data from a source node to (any) one member in the group of designed recipients in a network. In WDM network, the anycast requests can be used as an optimization tool to ensure survivability. If the anycast requests can be routed and delivered carefully, it is enough to find more free lightpath (or wavelengths) to other traffic (unicast or multicast). When the WDM network and the set of anycast requests are given, the anycast routing and wavelength assignment (ARWA) problem is to find a set of light-paths, one for each source, for anycasting messages to any one of the member in the anycast destination group such that not any path using the same wavelength passes through the same link. The goal of the ARWA problem is to minimize the number of used wavelengths. In this paper, the ARWA problem is formulated and studied; since ARWA problem is NP-hard, a hybrid method which combines simulated annealing and genetic algorithm technologies is proposed to solve it. In the proposed algorithm, the random routing method is used to generate the routing path from source to destination, heuristic algorithm is used to find the assigning wavelength of routing path. Nine types of perturbation schemes are proposed to generate the neighboring configuration, these perturbation schemes can avoid the proposed algorithm to trap into local optimum. Moreover, iterative improving technique is used to reduce the computing time for finding the new wavelength assignment. Simulated results show that the proposed algorithm can get better performance than other GA and heuristic algorithms. |