基于P2P网络的大规模视频直播系统

A Large-Scale Live Video Streaming System Based on P2P Networks

介绍了一种基于P2P(peer-to-peer)网络的大规模视频直播系统Gridmedia.该系统采用Gossip协议构建无结构的应用层覆盖网络,每个节点可以独立地选择自己的伙伴节点.在覆盖网络上,每个节点通过一种推拉结合的流传输策略从邻居节点获取数据.与DONet中的纯拉策略相比,推拉结合策略大幅度减小了终端用户观看视频的延迟,并有效降低了直播系统的控制开销.PlanetLab上的大量实验充分表明了该策略的有效性.Gridmedia的原型系统通过300Kbps的视频码流对2005年春节联欢晚会进行了全球互联网直播.晚会期间,全球范围内有超过500000人次通过系统观看了直播,最高在线人数达到了15239人,充分验证了系统的性能.

A P2P （peer-to-peer） network based large-scale live video streaming system called Gridmedia is presented in this paper. In this system, a gossip-based protocol is adopted to construct an unstructured application layer overlay. Each peer independently selects its own neighbors and uses a push-pull streaming method to fetch data from neighbors. Compared with the pure pull method of DONet, push-pull method greatly diminishes the accumulated latency observed at end users and efficiently reduces the control overhead of streaming system, both of which are evaluated by the experiments on PlanetLab. A prototype system of Gridmedia has been developed to broadcast the Spring Festival Gala Evening in 2005 over global Intemet with 300Kbps video stream and attracted more than 500 000 users all over the world with the peak concurrent online users of 15 239 during the event.