Multi-server video-on-demand system with arbitrary-rate playback support

In this paper, we propose a multi-server design for video-on-demand (VoD) systems that can provide different quality of service (QoS) guarantees by arbitrary-rate video playback. This design chooses a symmetric architecture that consists of a set of identically configured servers and supports arbitrary rates of video playback required by different clients in the following way. The playback requirements requested from all clients are first sent to the master server. If the master server decides to accept a new client, it distributes the task of the new client to all the servers, including itself. Through the pre-processing of the video streams, we can map the data of each frame of every video to a frame map. This frame map indicates whether a frame should be sent to the client at a given frame rate. In our multi-server design for a VoD system, using these frame maps and a suitable transmission schedule, a client can demand to play any video, at any playback rate and at any time. Furthermore, the VoD system provides a high degree of fault tolerance. This design not only can tolerate the failure of one or more servers, but also requires relatively small bandwidth capability or reservation for fault tolerance. In addition, this multi-server design can effectively overcome the hot spot problem of popular videos and keep the load balanced at the same time. Finally, we discuss how to generalize the proposed method for a large-scale VoD system with heterogeneous architecture.