Exploring Locality of Reference in P2P VoD Systems

A critical problem to P2P VoD systems is to provide efficient user interactivity support. In this paper, we study intra- and inter-video operations separately and aim to reduce the latency of these VoD operations by exploiting the locality of reference in user access patterns. With a relaxed definition of data chunk holder, intra-video locality can facilitate a high likelihood of a peer seeking within a video, to find a holder of the requested data among its neighbors. Tapping on this property, an aggressive cached publish scheme is designed to build shortcut over the DHT network so as to reduce the lookup delay. Inter-video locality is exploited via learning association rules from the collective viewing history. A fast association rule learning algorithm is proposed to infer the relations between videos in a distributed manner based on partial knowledge. Both search and content prefetch are incorporated to achieve low inter-video jump delay with minimal overhead. Our simulations demonstrate that the proposed schemes can reduce the lookup delay for seeking within a video and provide an efficient prediction-based prefetch scheme for inter-video access.