中文摘要：

组播技术从IP组播向应用层组播的发展，解决了IP组播部署难的问题．应用层组播依靠终端主机进行组播数据的转发，需要解决应用层组播的稳定性．最小延迟组播树的生成等问题．首先分析了影响应用层组播稳定和延时的3个因素：节点稳定概率、节点出度约束和节点间的通信延时．根据这些影响因素抽象出基于稳定概率的度约束边带权应用层组播树生成T—SDE模型，给出稳定度在T—SDE下的表达形式，并证明T—sDE问题属于NP—hard；其次通过分析节点对组播树稳定和延时的贡献，给出3种基于节点稳定概率和链路贡献度的T—SDE问题的近似解决算法；实验表明，该类算法生成的组播树在平均延时、最大延时和稳定度等方面有较大优势．

英文摘要：

Application layer multicast （ALM） which relys multicast data, has emerged as a viable solution to most However, the application layer multicast system, the minimum delay spanning tree algorithms of the high stability and Firstly, the paper an the stability probabil between two termina modeled into a spann application layer mul show that T-SDE is layer multicast in sta alyzes the influencing ity of terminal hosts, faces new chall of ALM, etc. dela factors of en on independent terminal hosts to relay problems associated ges, for instance, th In this paper, the rese with IP multicast. e stability of ALM arch focuses on the y spanning tree for application layer multicast. ALM stability and delay, and attributes them to the degree constraints of terminal hosts and the unicast cost ing tree based on stability probability, degree-constrained, and e ticast （T-SDE）. We propose a theorem of stability degree under NP-hard. Secondly, through analyzing the contribution of nod bility and delay, three algorithms of spanning tree are given base spanning tree is dge-weighted for the T-SDE, and es to application d on the stability probability and contribution link of nodes. Finally, from the experiment, the spanning trees of these algorithms are approved to have a great advantage in the average delay, the maximum delay, and the stability degree.