Research On Qos-based Multicast Routing Algorithm

With the popularity and development of Internet, there appear many new applications. These multimedia communications have the one-to-many characteristic, which result in bandwidth consume and congestion. Therefore, IP multicast techonlogy was proposed to resolve thebottleneck problem of Internet. The key of multicast is how to determine an efficient multicast routing. As the network may very big, and the topological structure and large amounts of traffic are changing continuously, the mutlicast routing problem is becoming very important and difficult. Dynamic joining and leaving of member, the participation of QoS information, and the need of network hierarchical routing are the obstacles to solve multicast routing problem. Network routing not only have to satisfy the need of user's different application, but also develop theresource-efficiency of whole network.The thesis is divided into six chapters:Chapter 1 briefly introduces the correspond content of multicast, including developing background of multicast routing, research status, multicast routing algori-thms, multicast routing protocols and the relative concepts of multicast tree, it also introduces the source and meaning of this thesis.Chapter 2 introduces the development and applications of multicast. The second part presented two kinds of multicast routing algorithm, and the popular multicast routing protocol.In Chapter 3, in point of QoS constraints, we described the definition, mathematic model, summarized the international QoS-based multicast routing algorithms and protocols in recent years.In Chapter 4, a distributed multicast routing algorithm with multiple QoS constraints, which solves the NP-complete problem in manner of a distributed computation is presented in MRMQ. The multicast tree by MRMQ constructed can not only meet the requirements of bandwidth and delay, but also to the maximum extent possible to meet the requirements of bandwidth and delay, and with the optimal (or near optimal) of the overall cost. Experimental results show that MRMQ it achieves a high routing success ratio with a modest message load, and generated multicast tree with a very low cost network.In Chapter 5, for the problem that flat routing is difficult to suit for the great network spreading, a hierarchical routing structure is proposed. The hierarchical network structure and the process of constructing tree are analyzed, a dynamic hierarchical multicast algorithm is proposed based on their characteristic. It has the scability and suit for great network. Experimental results show HMR is more efficient than DFMR and reduces the complexity of time and storage space.But the performance of multicast tree become lower.Chapter 6 summarizes this thesis, in addition, suggestions for future research are given.