Complementary Piece-Based Buffer Map for P2P VoDs Supporting VCR Operations

In this paper, we propose a buffer map notification scheme for Peer-to-Peer Video-on-Demand systems (P2P VoDs) which support VCR operations such as fast-forward, fast-backward, and seek. In order to enhance the fluidity of such operations, the size of pieces must be much smaller than conventional P2P VoDs, although it would significantly degrade the performance of buffer map notification schemes with respect to the observed piece availability and the efficiency of resource utilizations, since they strongly assume the sequential acquisition of required pieces. In order to overcome such problems, we propose a new scheme for buffer map notifications which complementarily uses piece-based buffer maps with a segment-based buffer map. The performance of the proposed scheme is evaluated by simulation. The result of simulations indicates that the proposed scheme reduces the intermittent waiting time of peers by more than 40% even under a situation in which 50 % of peers conduct the fast-forward operation over a range of 30 % of the entire video.