Abstract: As a multi-user data sharing strategy based on application layer，the deployment of application layer multicast on Internet is becoming more and more common.However，application layer multicast still has problems such as large delay，end system overload and so on presently.According to the routing-forward characteristic of application layer multicast，the application layer multicast problem is abstracted to degree- and delay-constrained minimum spanning tree problem，and then a novel application layer multicast routing algorithm based on particle swarm optimization is proposed.Simulation experiments indicate that the algorithm is good at scalability and efficiency.

Key words: multicast, particle swarm optimization, minimum spanning tree

摘要： 作为一种基于应用层的多用户数据共享方案，应用层组播在互联网中的应用日益广泛。然而目前应用层组播仍然面临着延迟过大、终端负载过重等问题。针对应用层组播的路由转发特征，将应用层组播问题抽象为度和延迟约束的最小生成树问题，进而提出了一种新的基于微粒群优化（Particle Swarm Optimization，PSO）的应用层组播路由算法。仿真实验表明，算法有着良好的扩展性和较高的效率。

关键词: 组播, 微粒群优化, 最小生成树