中文摘要：

SIP协议和P2P技术以其独特的优点在通信连接以及媒体传输方面起到越来越重要的作用，但由于缺乏实际应用的模型和相关设计，其实际应用没有开展起来．针对SIP中对实时流分发技术方面的不足，提出基于SIP与P2P相结合的多点实时流分发机制．在会话连接方面采取SIP协议，保证会话者之间的可靠通信．在实时流分发方面，采用多点P2P技术．各个节点之间的媒体传输使用应用层多播的方法，并提出一个有效的建立应用层多播树的算法，该算法综合权衡了实时流传输的延迟和带宽两个媒体传输中的关键要素．仿真结果表明，该结构能够有效地提供高质量的实时流服务．

英文摘要：

To solve the problem of the deficiency of SIP （Session Initiation Protocol） for multipoint session, a design of SIP combined with P2P multipoint real time stream session mechanism is presented in this paper. To transmission the real time stream among the multipoint, new application layer multicast tree construction algorithm and real time stream distribution algorithm are put forward. In this application layer multicast tree, the two key factors of both bandwidth and delay in streaming media are taken into considered. The simulation and the experiments show that the design is practical and has a great improvement on the quality of real time service.