Research Of Adaptive And Reliable Multicast Routing Technology In MANET Network

A MANET network is famous for faster organizing capability and broad application, especially in the military communication. For most of network application supported by group communication, multicast routing technology becomes one of the hot researches in recent years. There are many multicast routing protocols of MANET network have been proposed, which are based on different particular network, every multicast routing protocol has own advantages and disadvantages, suitable for different network environment. In order to take advantages of these protocols in different network, adapt to the time-variable network environment, improve the network performance, we focus on selecting an optimal multicast routing protocols adaptively according their comprehensive performance and the characteristics of current network scenarios.First of all, we studied the existing multicast routing protocols and various classifications of them. We divided them into two categories, Structure-based protocol and Flooding-based protocols, according to whether or not they build multicast distributed structure in multicast communication. Structure-based protocol can be divided into two categories, Tree-based and mesh-based. According to the above classification standard, we chose four typical multicast routing protocols as the research object, MAODV which represents Tree-based protocols, ODMRP which represents mesh-based protocols, FlOOD and BCAST which represent Flood-based protocols.Secondly, we simulating the above four protocols by using NS2. In order to study the differences among performance of multicast routing protocols in different network scenarios, we set different network simulation scenarios by changing the maximum speed of nodes, the number of multicast group member and multicast source.Meanwhile, we analyze the performance of multicast routing protocol from four aspects:packet delivery ratio, average delay, packet transmission efficiency and routing overhead. Results suggest that among Structure-based protocol, Tree-based has the advantages of high efficiency, mesh-based with high robust. However, as Structure-based need to acknowledge the state of the network and store some network information, they has limit to adapt to the change of network topology. In contrast,Flooding-based protocols have high reliability whether network mobility is high or not.However, the high reliability of Flooding-based protocols on is guaranteed by the sacrifice of bandwidth resources. In addition, Flooding-based protocols is not affected by the number of multicast members, its scalability is higher than Structure-based.Based on the above research, we introduce the adaptive neural fuzzy inference system(ANFIS) to model the performance of multicast routing protocols, and using it to establish the optimal multicast routing protocol selection strategy database. From which, we can obtain the performance index(packet delivery ratio, average delay,packet transmission efficiency and routing overhead) of the multicast routing protocol under any network scene. By using arbitrary objective function, the optimal multicast routing protocol under different scenarios can be quickly obtained. At the same time,given an objective function which describes traffic characters, through training and learning ANFIS with known multicast routing protocol selection strategy, we can get an optimal multicast routing protocol map.Finally, comparing with the NS2 simulation results under the same scenario, the effectiveness of presented multicast-routing-protocol-oriented adaptive selection algorithm is proved.