Research And Implementation Of Delay-constrained Multicast Routing Algorithm

With the era of video communication coming which integrates voice, data and images, a lot of real-time multimedia services in computer network, such as streaming media, video-on-demand, network war games and distributed database, are increasing rapidly, leading to much more intensive bandwidth consumption and network congestion. To some extent, Multicast technology can solve the problem of network bandwidth bottlenecks in the video communication process by using less network bandwidth and so being able to fundamentally reduce the load of network, and it has become an hot spot in the research field of network.Routing is the key problem of the multicast technology: how to construct a multicast tree having the minimum cost from the source node to each of destination nodes. Towards the real-time characteristic in most of the multimedia services, this paper focuses on delay-constrained multicast routing based on low-cost shortest path tree algorithm.This paper summarizes the state-of-art heuristic multicast routing algorithms, and analyzes existing problems. It aims at real-time static multicast for multimedia applications and proposes a fast delay-constrained multicast algorithm based on shortest path tree of low cost. The algorithm leverages between delay and cost and adds delay-constrained strategy in the fast shortest path tree algorithm FLCSP. Simulation results show that the algorithm is more effective than DCSP algorithm of the similar type, and the total cost is also lower. This algorithm is suitable for destination node dense concentration distribution pattern, and can be applied to real-time multimedia multicast services.To meet the requirement that members of multicast group could join or leave the multicast tree at any time in applications, this paper studies some dynamic shortest path tree and improves a dynamic delay-constrained multicast algorithm. Considering the idea that the shortest path sub-graph can store the shortest paths between two nodes in the algorithm DLSPT, and the constrained delay, this algorithm only selects the connected node in shortest path subgraph and multicast tree when adding a new destination node to the multicast tree, so it can avoid the search for non-shortest paths, and thus reduces computing time. Simulation results show that, the algorithm increases the computed efficiency of building up dynamic multicast tree and keeps the tree's feature of low cost.Eventually, this paper explores the multicast routing technology in Mobile Ad Hoc Network under 3G condition, and gives some advice on improving and designing MANET multicast routing algorithm based on 3G.