Studies On Distributed And Multi-Path QoS Multicast Routing Algorithms And Protocols

With the rapid development of the Internet, group communication applications such as videoconferencing, network audio/video broadcasting, stock information distribution, remote education, CSCW, and distributed interactive simulation, etc, are emerging. All these applications rely on multicast technology. Multicast is different from unicast and broadcast in that it distributes packets to a specific set of hosts as a group. The most significant character of multicast is that its consumption of network resources does not increase with the number of hosts. So multicast is a very hot area of network technology and attracts attentions of many researchers. Multicast has many researching directions such as routing algorithms and protocols, group membership management, multicast address allocation, admission control and multicast applications, etc.This thesis first studies the general description of QoS multicast routing problem, gives a survey of multicast routing algorithms and protocols, divides existing algorithms and protocols into some classes, and discusses the complexity of multicast routing. It also studies the standards of the performance evaluation of multicast routing algorithms and protocols and simulation methods.The main body of this article studies QoS multicast routing algorithms and protocols. It also studies admission control and multicast applications. 1) We deeply study a new type of QoS multicast algorithm based on bounded flooding technique. This article proposes a novel QoS-aware multicast routing protocol aiming at alleviating the memory overhead of the routers for setting up multicast trees and improving scalability of the protocol. In our scheme, every node needs to maintain a two-level forwarding table which contains information about its immediate neighbors (routers reachable in one hop) and its second-degree neighbors (neighbors of an immediate one). By means of the information about the second-degree neighbors, a router can forward Join_Probe messages intelligently instead of flooding them blindly. Our protocol also utilizes multi-path searching to increase the probability of finding feasible branches when connecting a new node to the multicast tree. The paper describes the details of the data structures of the protocol and the algorithm of building a distribution tree. It shows the effectiveness of this proposed protocol byevaluating the protocol's performance in terms of average call acceptance ratio and average control message overhead through simulation.2) The article also studies an integrated optimization of multicast route and its algorithm, and proposes a very efficient integrated heuristic function which can be used to optimize multicast delay, bandwidth and network cost to some extent. The function is combined into the proposed protocol QMoBF.3) We study another style of QoS multicast protocol made by integrating the centralized methods and the distributed ones in order to reduce the average control message overhead and keep a high call accepted success ratio. Our proposed protocol has got the design destination.4) This thesis researches the mechanism of integrating our QMoBF with an admission control algorithm. Using delay and bandwidth as the parameters, we develop an admission control criterion which can be used in the reduced service-set architecture supporting load-controlled service, guaranteed service and best-effort service. Our QMoBF protocol can develop further based on this work because the protocol needs an admission control mechanism.5) Application based on network multicast technique is also studied in this thesis. Recognizing traditional communication models of videoconferencing systems have many disadvantages such as many connections, high complexity and low scalability, we propose a new videoconferencing design rule that can enable videoconferencing system simpler, more feasible, robust and scalable. We have developed an IP multicast videoconferencing based on Microsoft's TAPI, a very powerful tool for developing H.323 and IP multicast videoconferen...