An improved patching scheme for video-on-demand servers

The main bottleneck for a VOD service is bandwidth of storage or network I/O due to the high bandwidth requirements and long-lived nature of digital video. Patching is one of the most efficient techniques to overcome the bottleneck of the VOD service through the use of multicast scheme. In this paper, we propose a new patching scheme for improving the typical patching technique by jointly using the proxy prefix caching and the client buffer expanding techniques. Our propose scheme extends the patching window size by caching the prefix of the video in proxy. We also expand the client buffer space into the proxy buffer for storing and sharing the overflowed streams from the client buffers. Due to the extended patching window size and the prefix in the proxy, the server bandwidth is required significantly less than that of the typical patching technique. In the performance study, we show that our patching scheme can reduce the server bandwidth requirements compared with the existing patching techniques.