Multicast Routing and Spectrum Assignment in Flexible-Grid Optical Networks Based on Light-Tree Sharing Approach

摘要

Studies on Flexible-Grid technology reveals that it provides desirable solution for next generation high-speed network design. Multicast Routing and Spectrum assignment (MRSA) in Flexible-Grid Optical Networks (alternately Elastic Optical Networks) generates a multicast tree for each multicast session request and spectrum frequency slots are allocated to each of the edge of the multicast tree. Orthogonal Frequency Division Multiplexing (OFDM) technique can be used to implement MRSA algorithm. Spectrum frequency slots are allocated to the edges of the multicast tree obeying the spectrum continuity constraint and spectrum contiguity constraint, thus creating a multicast light-tree. In this paper we have proposed a lighttreesharing based multicast routing and spectrum assignment technique. Similar multicast requests are grouped together and their bandwidth requirements are added up. For each multicast session request a layered auxiliary graph is selected based on available spectrum in the network and the request's bandwidth demand. An efficient light-tree is generated from this auxiliary graph, first for the clubbed request and then for the individual requests separately. The simulation results show that our proposed algorithm significantly reduce the average tree size and increases number of requests satisfied than the well-known existing algorithm mentioned in literature. Incidentally the average number of splitters required is also reduced.