For content delivery in Peer-to-Peer (P2P) video streaming systems there are two main approaches: push-based and pull-based. In P2P Video-on-Demand (VoD) systems, neighbor peers might watch the same video with very large differences in viewing point; thus using push-based approach is not sufficient for these systems. Also with using pull-based approach, peers need large buffers to achieve better quality of service, and must send large size buffer-maps to their neighbors, which is not efficient. In this paper we study buffer-map exchange challenges in pull-based P2P VoD streaming systems and propose an adaptive mechanism for decreasing bandwidth and computational overhead via sending only a portion of information included in the buffer-map with regards to the viewing point of each neighbor. The bandwidth overhead analysis of the proposed mechanism is validated by network simulation and the results show that our mechanism effectively reduces bandwidth overhead.
video-on-demand, peer-to-peer, buffer-map exchange,