Research Of Multi-constrained QoS Multicast Routing Algorithms Based On Genetic Algorithm

In computer networks, multicast routing is network-layer functions that constructs paths, along which the same message from source node can be sent to multiple destination nodes, and the key of multicast problem lies in the determination of multicast paths. The general way to realize multicast is to establish multicast tree, which is a spanning tree that take the root as source node and share many links in transmitting the message to the destination set .The multicast tree has three advantages. At first, the message is transmitted to different multicast membership by parallel mode, thus decreaseing the delay of message transmission. The second, the message only need to be replicated at forking nodes, so it saves the bandwidth, and optimizes the network performance.Multicast routing algorithms are used to compute multicast trees of good performance that satisfy QoS requirements for all kinds of business.Now, researches on multicast routing algorithm mainly focus on multicasting algorithm without constraints and delay-constrained multicast routing and also use heuristic algorithm. How the new optimization algorithm--genetic algorithm will be applied to QoS multicast routing algorithm is the emphases of research. A new approach to resolve QoS multicast routing problem has been provided through parallel search and group improvement of the algorithm.Firstly, the paper summarizes multicast communications in computer networks, presenting the basic concepts, classification, fundamental characteristics and application, and then studies the multicast technology and application, the multicast routing technology and the multicast touting protocol. The paper also introducs the basic concept of QoS.Secondly, the paper researches the multicast routing. It introduce the fundamental concepts, parameters, network parameter, network model, optimization criterion of the multicast routing ; It analyses the present situation of multicast routing algorithm; It studies several practicable multicast routing algorithms and present the execution process. Thirdly, the paper describes the basic concept, characteristic and application of genetic algorithm, analyzes in detail the fundamental elements of genetic algorithms, the problems in genetic algorithm and its improving method, and it analyzes the situation and developing trend of genetic algorithm to multicast routing.Lastly, according to the characters of QoS multicast routing and optimization character of genetic algorithm, the paper emphasizes an improved algorithm of the Dijkstra algorithm and the QoS multicast routing algorithm based on genetic algorithms and provide the empirical analysis and simulation validation. The improved algorithm further solves multi-constraint QoS multicasting routing optimization by comparing with other algorithm and experiment test ,and it will be faster in application to searching in the network at large scale .As a result, the algorithm mentioned in this paper is feasible and effective.