Optimal and efficient merging schedules for video-on-demand servers

The simplest video-on-demand (VOD) delivery policy is to allocate a new media delivery stream to each client request when it arrives. This policy has the desirable properties of “immediate service” (there is minimal latency between the client request and the start of playback, assuming that sufficient server bandwidth is available to start the new stream), of placing minimal demands on client capabilities (the client receive bandwidth required is the media playback rate, and no client local storage is required), and of being simple to implement. However, the policy is untenable because it requires server bandwidth that scales linearly with the number of clients that must be supported simultaneously, which is too expensive for many applications.