关键词: 对等网流媒体, 网络编码, 数据调度, 性能优化

Abstract: Compared with the traditional pullbased scheduling methods in P2P live streaming systems, the random push scheme with random network coding, named R2, has a lot of advantages such as improving video quality of service, reducing overload of streaming servers and enhancing the resilience to nodes dynamics. However, the random push strategy in R2 is prone to producing a large amount of redundant coded blocks, thus wasting some precious network bandwidth. In this paper, a novel hybrid push/pull scheme with network coding, customR2, was proposed. When one downstreaming node received the most of coded blocks of one segment actively pushed from its upstreaming seeds, it would notify its seeds to stop push operations and start pull operations for the remaining coded blocks, to reduce the quantity of redundant blocks. By the simulations, the comparison between customR2 and R2 was conducted with respect to playback delay, streaming rate and network size. The results show that customR2 outperforms R2 in terms of redundancy ratio of coded blocks and playback quality.

Key words: Peer-to-Peer (P2P)stream media, network coding, data scheduling, performance optimization