Scalability Of QoS Multicast Routing Protocol And Its Application In Diffserv Networks

QoS multicast routing is one of the most important mechanisms of the QoS network architecture, its aim is to find a multicast tree which not only covers all members but also guarantee all QoS requirements of the real-time applications. The research of QoS multicast routing drow much attention in recently years, and there are many QoS multicast protocols and algorithms which have been proposed. However, several problems are still not solved well such as scalability problem. For QoS multicast routing protocols, one of the most effective factor is the amount of control messages. Although flood or multi-path search can improve success ratio, the amount of control messages will grow exponentially. Time complexity is the most effective factor of the scalability of QoS multicast routing algorithms, and how to find global optimal multicast tree rapidly is still a hot-point and difficult problem. Despite designing scalable multicast routing protocol and algorithm, scalability of multicast service is very important. As we know, DiffServ is a scalable solution for supporting QoS in the Internet, while it only suits to point-to-point unicast. Due to the fundamental differences between DiffServ model and transitional IP multicasting, Several problems will occurred in DiffServ multicast provision such as NRS( Neglected Reservation Subtree), scalability, heterogeneity, inter-class Fairness problem.In order to solve the above problems, a scalable multicast routing protocol with QoS constraints (MRPQoS) is proposed in this dissertation at first. It could absolutely make distributed computering into realization and then solve the problems successfully by the integration with local search and global search,single-branch search and multi-branch search. Then, a fast multicast routing optimal algorithm with QoS constraints based on Tabu-search(TSQMA) is proposed. It can improve the search speed, and make a better solution by using the merits of Tabu-search, and is faster, easier for implementation, and more suitable for large group scale. Finally, after deeply studying on the conflict between DiffServ model and traditional IP multicast model and prons and cons of current solutions, DMM - a DiffServ multicast model and the per-class QoS routing multicast algorithm(PQMRD)suited for DiffServ network is devised, which can improve network resource utilization ratio, and can effectively solve the NRS Problem, scalability problem, heterogeneity problem and inter-class fairness problem etc.