Adaptive chaining scheme for distributed VOD applications

In distributed video on demand (VOD) applications, a client station buffers a shifting window of its displaying video so that the video stream can be chained from the client to another one arriving within the window, instead of consuming a server stream for each new request. This scheme is called video chaining that can reduce the load of video servers significantly. In this paper, we propose a novel adaptive chaining scheme that extends the basic chaining scheme with two new techniques: two-way bridging and multicast chaining. The two-way bridging method employs video buffers as forward and/or backward bridges to extend each video chain as long as possible. It provides nearly twice the performance gain than basic chaining in terms of server I/O load reduction. Mathematical analyses for both schemes are also given. The multicast chaining method maximizes the multicast degree of each video chain so that lower data delivery cost per video session can be achieved. Our scheme maintains the video chains optimally to shift the load to active clients so that the I/O bottleneck of video servers is released