The Design And Realization Of Mixed Multicast Live Streaming System

With the development of the network technology and the multimedia technology, multimedia applications become increasingly rich on the Internet. As the representative, live streaming media system has been widely used in video conference system and distance learning system.Live streaming media system is a typical application of group communication model. This paper mainly focuses on the research of unicast, broadcast, network layer multicast, application layer multicast and hybrid multicast model MixCast etc. Unicast has bad expandability, and broadcast only meets the needs of users in the same LAN. Network layer multicast is the most effective group communication model but it is difficult to be deployed because of the need of hardware support. Application layer multicast has good expandability and is easily deployed but it consumes more network resources than network layer multicast. MixCast model which integrates the advantage of both the network layer multicast and the application layer multicast is a good group communication model.Hybrid multicast based on MixCast model is designed and implemented in the live streaming media system. The roles of the system are divided into three types: ListServer, MixCast data proxy (MDP) and MixCast peer(MP). Hybrid multicast is implemented by MDP. The data is sent synchronously by means of the application layer multicast and the network layer multicast. An original system has been implemented. Centralized controling application layer multicast solutions have been put forward which mainly solve the problem how MP joins the multicast tree whose root is MDP, including the dispose of the join, the normal and abnormal withdrawal of nodes. A solution that streaming media is distributed by means of network layer multicast in the MDP is put forward. Streaming media header information is sent to a multicast group by the MDP while streaming media data information is sent to another multicast group. Clients receive header information and data information separately by joining the two groups. The system has been tested in local area and clients play fluently. Theoretical analysis and simulation experiments show that the system occupies less bandwidth and has great expandability.