基于封装和聚集组播的区分服务组播实现方案

给出一种区分服务组播的三层实现模型，在此基础上给出一种基于封装和聚集组播的区分服务组播实现方案：EADSMCast(Encapsulated and Aggregated DiffServ Multicast). 一方面通过对基于封装的DSMCast方案的改进，在组播分组头部封装聚集组播树上核心路由器的转发信息，保持了区分服务域中核心路由器的无状态性和可扩展性；另一方面，通过对聚集组播的组-树匹配算法的改进，使多个具有相同或相似转发结构的组播组共享一棵聚集组播树，有效地减小了边界路由器中组播路由表的规模。仿真实验结果表明，EADSMCast是一种能够支持异构QoS组播、可扩展性良好的区分服务组播实现方案。

DiffServ Multicast Scheme Based on Encapsulation and Aggregation

A 3-layer model providing DiffServ multicast is proposed. Base on the model, a novel DiffServ Multicast scheme named EADSMCast (Encapsulated and Aggregated DiffServ Multicast) has been designed. EADSMCast is derived from DSMCast by encapsulating forwarding information of all core routers of the aggregated tree into each multicast packet’s header to provide core statelessness for scalability. By the way, an improved group-tree matching algorithm is also proposed. The algorithm makes several groups having similar forwarding structure, share the same aggregated multicast tree, so that the size of multicast routing table maintained by edge routers could be reduced significantly. The simulation results indicate that EADSMCast is a scalable scheme for supporting heterogeneous QoS multicast.