The Study Of Time-Delay Sensitive Multicast Routing Algorithms

In computer networks, providing multicast for multimedia real-time service is oneof the hottest issues in current research field. Multicast routing is a communicationmeans, which is from a host computer to many other host ones, but not to all. There arelots of applications of multicast, such as multimedia meeting, long-distance teaching,data distribution so on and so forth. In this paper, the existing heuristic algorithms for Steiner tree problem aresummarized firstly. Secondly, a real-time least-cost dynamic multicast algorithm ispresented, which makes the problem much easier by using the transpositional function.It overcomes the shortcomings of the traditional algorithms, which deal with the costand delay separately and need a lot of retrospect and more multimedia services need thenetwork guarantee the real-time requirements, so the network resources can be utilizedefficiently. Then, an improved genetic algorithm is proposed to solve this problem. Thisalgorithm makes trees with the source and all destinations are the space of operation andfilter operation. With hybrid selection operator, competition among brothers, greedyoperation, filter operation. It can improve global convergence property and convergencespeed. Furthermore, an approach of one destination to another is studied and amathematical model and corresponding algorithm to solve the problem of QoS routingis given, in which semidefinite programming is used .The basic problem of QoS routingis an optimal problem satisfying multi-constrained conditions from a source node to onedestination. At last, the multicast routing in WDM optical networks is discussed andRAW (routing and assignment of wavelength) problems are summarized.