Priority Scheme for Window-Based Video-on-Demand Transmission on BitTorrent-Like Peer-to-Peer Networks

Peer-to-Peer (P2P) networks are distributed systems where no central authority rules the behavior of the individual peers. These systems rely on the voluntary participation of the peers to help each other and reduce congestion at the data servers. BitTorrent is a popular file-sharing P2P application originally designed for non real-time data. With minor modifications concerning the peer selection among others, it can also be used for real-time applications. One major issue that impacts the performance of these networks is related to the fact that it is not uncommon to find users that have initiated a file transfer and decide to leave the system before the end of the download or when seeds leave the system shortly after downloading the complete file. In this work, a priority-based scheme for streaming stored playback video-on-demand services in window-based peers selection strategy in P2P networks is proposed. The priority scheme benefits the peers that are more likely to remain longer in the system by serving them first over peers that are statistically more likely to abort the download. The window-based peer selection strategy allows an efficient mechanism to select the downloader peers according to their progress in the file download process relative to the progress of the downloading peers. The aforementioned strategy is analyzed using both a fluid model and a Continuous Time Markov Chain. Also, abundance conditions in the system are identified.