Time-Shifted Streaming in a Peer-to-Peer Video Multicast System

We propose a peer-to-peer (P2P) streaming system that allows users to individually pause and resume a live video stream as well as to view video that was streamed before the particular user joined the session. Such time-shifted streaming can be provided by caching a portion of the video stream at each peer and serving it asynchronously. We analyze the availability of video contents in the P2P overlay using a Poisson model of peer arrival. We also discuss fast prefetching, which reduces video disruption due to peer churn and also allows peers to disseminate content more quickly, thus reducing server bandwidth requirement. We extend the Stanford Peer-to-Peer Multicast (SPPM) protocol to support time-shifted streaming. The overlay is constructed by selecting parent nodes that are expected to most effectively support fast prefetching. Extensive network experiments show that fast prefetching effectively supports time-shifted streaming with reduced server load.