Event-Driven High-Priority First Data Scheduling Scheme for P2P VoD Streaming

The peer churn rate in the peer-to-peer (P2P) video-on-demand streaming service is much higher than in the P2P live streaming service, which makes the data scheduling problem more challenging. First, the available upload bandwidth information used in the data scheduling scheme is often inaccurate due to the peer churn, which lets a peer make bad scheduling decisions and leads to load imbalance. The higher peer churn makes this problem worse. Secondly, the higher peer churn exacerbates the bandwidth contention problem which occurs between a newly joined peer and some already-existing peers. To tackle the above two challenges, we propose an event-driven high-priority first data scheduling scheme, called EHPF scheme. To tackle the first challenge, we design a piggyback mechanism based on the event-driven mechanism. To tackle the second challenge, we design a priority calculation strategy to differentiate the requests from the newly joined peers and those from the already-existing peers, and use the high-priority first policy to allocate the upload bandwidths of peers. Through simulations and a real environment experiment, we demonstrate that the EHPF scheme outperforms the periodical data scheduling scheme in terms of startup delay, streaming quality and load balancing.