P2PVR: A playback offset aware multicast tree for on-demand video streaming with VCR functions

Tree-based peer-to-peer multicast overlays have been widely proposed to provide on-demand video streaming services. However, alleviating the server load in large-scale, dynamic environments such as the Internet remains a major challenge. Accordingly, this paper proposes a new peer-to-peer on-demand video streaming system, designated as peer-to-peer personal video recorder (P2PVR), which facilitates essential VCR functions in an efficient manner. In the proposed architecture, the peers are organized into a playback offset aware tree-based overlay, in which they share streaming data with other peers having a similar playback offset. In addition, a semi-decentralized directory service is developed to assist peers in searching only those parts of the tree known to contain eligible parent nodes, i.e. nodes which possess the expected streaming data. The performance of P2PVR is evaluated by performing a series of experiments on the PlanetLab platform. The results show that P2PVR yields a significant reduction in the server stream stress and achieves a reasonably low playback discontinuity under dynamic network conditions whilst simultaneously granting a low control overhead and startup latency.