Based On Application Layer Multicast Video Broadcast System

Along with the continuous development of the Internet, the information on the network has grown up from the traditional texts and pictures to multi-media represented by audio and video. As for the one-to-many video transportation in a large scale such as the video living broadcast, the multicast is a kind of ideal solution. However, for some causation resulted from the absence of technology and management, the IP multicast can not be deployed in a large-scale to satisfy the need of multi-media data service. So, nowadays, some researchers put forward a new thinking to achieve the complicated function of multicast at the end hosts. That is the application layer multicast.Designs and implements a multimedia living broadcast system based on application layer multicast, which can provide real-time multimedia data service for wide scale customers .In this system, the data source node obtains stream media data from the stream media server; the data forwarding tree constitutes and maintains its tree structure according to the end-to-end delay between end hosts, and chooses those links which have lower delay and higher bandwidth available as its branches to lower the absolute delay along the branches; the end nodes replicates stream media data and forwards them to other end nodes using RTP and RTCP protocol to transport real-time media data. The multicast experiment on the campus network and the simulative experiment can prove that this system completes the living broadcast of stream media at a cost of smaller delay and lower control overheads, and that with the favorable extensibility and reliability this system can be arranged easier than IP multicast.