Abstract: This paper discusses the multicast routing problem with multiple QoS constraints, and describes a network model that is suitable to research such routing problem. It presents a distributed QoS multicast routing protocol (DQMRP). The DQMRP attempts to significantly reduce the overhead of constructing a multicast tree with QoS constraints. In DQMRP, a multicast group member can join or leave a multicast session dynamically, which should not disrupt the multicast tree. It also attempts to minimize overall cost of the tree, and satisfies the QoS constraints and the requirements of least cost. This paper gives the proof of correctness of the DQMRP, and evaluates the performance measures of the protocol using simulation. Analysis and simulations show that DQMRP is better than other protocols and is fitter for the network situations with the status changed frequently and the real-time multimedia applications. Control overhead and access latency can also be reduced greatly.

Key words: Multicast routing; Protocol; QoS routing; Distributed multicast routing

摘要： 研讨了具有QoS 约束的分布式多播路由问题。描述了一种适应于QoS 多播路由的网络模型，提出了一种分布式QoS 多播路由协议(DQMRP)。DQMRP 只要求网络链路(或节点)的局部状态信息，不需要维护全局状态信息。DQMRP 可有效地减少构造一棵多播树的开销，多播组成员能动态地加入/退出一个多播会晤，且不干扰现有的多播树。给出了DQMRP 的正确性证明。仿真实验结果表明：DQMRP具有较低的控制信息开销和节点加入时延，较其它协议更适合于网络状态变化比较频繁的环境以及实时多媒体应用。

关键词: 多播路由；协议；QoS 路由；分布式多播路由