Design And Simulation Of Dynamic Multicast Routing Algorithm With Sparse Light Splitter Configuration Constraint

Multicast routing and wavelength assignment is an important aspect of the multicast in optical network. Compared with the IP layer multicast, there are some special constraints in optical layer multicast, including the wavelength continuity constraint, sparse light splitter configuration constraint and energy injury constraint. It is necessary to meet the above three constraints for a feasible multicast routing. But the multi-constrained multicast routing calculation is very complicated and difficult to achieve. Taking into account the sparse splitter configuration can help reducing the energy injury and configuring splitters and full wavelength converters for all nodes in WDM network is still unrealistic in nowdays, so dynamic multicast routing problem with sparse splitter configuration constraint and wavelength continuity constraint is studied in this thesis.First, the key technologies that support multicast are studied, including multicast mechanisms, node structure and function modules of control plane. Then, the existing sparse splitter configuration constrained multicast routing algorithms are summed up to three main ideas, they are re-routing based idea, multicast tree expansion based idea and virtual source based idea. The advantages of virtual source based idea compared with source based ideas are analyzed. Finally, based on virtual source based idea, with the purpose of improving the utilization of network resources and reducing the blocking rate, the existing virtual source-based multicast routing algorithms are studied indepth and a new virtual source based algorithm named N_VSBA is proposed. The minimum interference routing algorithm is introduced to address the problem that all nodes between two VS nodes establish connection using the only one pre-calculated path. The MPH algorithm is introduced to resolve the problem that the TaC founction of MI nodes can not be used when joining the light tree in traditional algorithms. The basic idea of N_VSBA is:first calculate multiple alternate paths between VS nodes and construct auxiliary graph. When multicast request arrives, setting the cost of the edge dynamicly considering the remaining resource of the link and the impact to the possible coming request and calculate the minimum cost tree contains VS node in the auxiliary graph. Finally, calculate the minimum cost tree that contains the destination node of each VS node set using the constrained MPH algorithm.Simulation results show that compare to the existing virtual source-based multicast routing algorithm the new algorithm can reduce the blocking rate, the average wavelength link number and the maximum number of wavelengths by11%.11%and17%. The conclusion is that under the same conditions, N_VSBA can get a good performance.