Optimal Placement of Split-capable Nodes for Optical Multicast Routing in WDM Networks

摘要

We consider the multicast routing problem for large-scale wavelength divisionmultiplexing (WDM) optical networks where transmission requests are established bypoint-to-multipoint connections. To realize multicast routing in WDM optical networks, some nodesneed to have light (optical) splitting capability. A node with splitting capability can forward anincoming message to more than one output link. We consider the problem of minimizing the number ofsplit-capable nodes in the network for a given set of multicast requests. The number of wavelengthsis fixed and given a priori. We propose a genetic algorithm that exploits the combination ofalternative shortest paths for the given multicast requests in order to minimize the number ofrequired split-capable nodes. This algorithm is examined for two realistic networks constructedbased on the locations of major cities in Ibaraki Prefecture and those in Kanto District in Japan.Our experimental results show that the proposed algorithm can reduce more than 10 of split-capablenodes compared with other routing algorithms whereby the optimization for the split-capable nodeplacement is not taken into account.