It is well-known that the seeking operation is pervasive in interactive VoD playbacks. Efficient chunk discovery upon seeking thus becomes a critical issue in P2P VoD design. Existing studies have largely focused on uniform chunk access frequencies, which does not reflect real statistics. Also, over 80% seeking requests are of short distances, whose potentials and impacts have yet to be explored. To address the above practical challenges, we develop D-Splay, a novel structure for indexing data chunks in a P2P VoD system. D-Splay is an efficient frequency-aware indexing structure that adaptively adjusts itself to realize quick and low-cost chunk discovering. In this paper, we present the detailed design of D-Splay as well as a practical P2P VoD architecture with D-Splay. We further develop an adaptive pre-fetching policy that explores the knowledge available from the D-Splay overlay. Through extensive simulations, we demonstrate that it greatly improves the responsiveness and success rate of seeking operation, particularly for short-distance seeking.
