中文摘要：

加入叠加网多播的主机在带宽及其他方面存在异构性．在叠加网多播协议设计中考虑这些异构性，按优先级组织节点关系与系统架构，将提升系统的整体性能．本文利用Mesh架构叠加网多播中大部分数据经几棵树所组成的树子集进行传播的特性，定位主干多播树，在此基础上设计优先级抢占算法，使高能力节点抢占低能力节点位置，从而使高能力节点尽可能的靠近源点，以此提升系统整体性能和贡献较大节点的业务质量．本文给出了协议设计，并对目标架构进行了分析，最后通过仿真实验表明了本算法的有效性．

英文摘要：

Hosts in overlay muhicast systems have heterogeneity in both of bandwidth and other characteristics. Considering the heterogeneity in design of overlay multicast protocol and organizing nodes and construction in priority may improve the overall performance. In this paper, by identifying the main distribution trees which carry most of the data delivery from Mesh overlay multicast systems, and designing a heuristics prioritization preemption algorithm in the context of heterogeneity of nodes, the high priority nodes will preempt low ones, so the nodes which are more powerful are to be near the source, this will result improvement of the overall system performance. The design of protocol was also presented in this paper, the target structure was analysized and finally verification was carried out by simulations.