中文摘要：

应用层多插技术是互联网研究的一个重要方向．本文提出一种新的应用层多插模型DHCM，该模型采用改进的IHC算法，对cluster的密度进行层次划分，通过组建一个密度树实现最短路由，并把peer-to-peer技术用在数据传输上，最终把视频服务器的内容分发到密度树上的各个主机，实现应用层多插．这种密度层次划分的cluster满足单调性和同构性．实验证明DHCM可以在视频流传输上具有高效性和健壮性．

英文摘要：

Currently IP multicast copies and transmits data in router so that it cannot meet the demand for its disadvantages, and it is a trend that multicast is realized through route selection at end hosts. This paper has proposed a new model of application level multicast named DHCM （Density-based Hierarchical Clustering Multicast）which has improved IHC arithmetic. DHCM divides the hosts into many hierarchies according to their density, and constructs a density tree to realize the shortest routing. The tree delivers the content of video server to each host in density tree and uses a p2p scheme in data transmission. By this way the application-level multicast has been realized. This density tree has the homogeneity and monotonic properties. The experiment result has proved that DHCM can transmit the video stream efficiently and robustly.