An adaptive buffer-map exchange mechanism for pull-based peer-to-peer video-on-demand streaming systems

Unlike P2P live video streaming in which all the peers in a channel watch a video with tiny differences in viewing points, in P2P video on demand (VoD) streaming systems, neighbor peers may watch the same video with more different viewing points; therefore, using push-based approach is not efficient for such systems, and the overhead of the pull-based approaches is challenging due to the periodical exchange of buffer-maps among the peers. In pull-based P2P VoD systems, to achieve better quality of experience it is necessary to use large buffers at the peers that results in more buffer-maps exchange overhead. In this paper, we study buffer-map exchange challenging in pull-based P2P VoD streaming systems and propose an adaptive mechanism for decreasing overhead by sending the buffer-maps with regard to the viewing points of the peers. Bandwidth overhead of the proposed mechanism is independent of the used buffer sizes and is less dependent to the buffer-map exchange period. By using this effective mechanism, better quality of service can be achieved through using large buffers at the peers, without increasing in the overhead. Our simulation based performance evaluation shows the efficiency of the proposed mechanism in decreasing the bandwidth overhead of buffer-map exchange in P2P VoD streaming systems.