Video staging: A proxy-server-based approach to end-to-end video delivery over wide-area networks

Real-time distribution of stored video over wide-area networks (WANs) is a crucial component of many emerging distributed multimedia applications. The heterogeneity in the underlying network environments Is an important facto r that must be taken into consideration when designing an end-to-end video delivery system. In this paper, wt? present a novel approach to the problem of end-to-end vi deo delivery over WANs using proxy servers situated between local-area netw orks (LANs) and a backbone WAN. A major objective of our approach is to red uce the backbone WAN bandwidth requirement. Toward this end, we develop an effective video delivery technique called video staging via intelligent uti lization of the disk bandwidth and storage space available at proxy servers . Using this video staging technique, only part of a video stream is retrie ved directly from the central video server across the backbone WAN whereas the rest of the video stream is delivered to users locally from proxy serve rs attached to the LANs. In this manner, the WAN bandwidth requirement can be significantly reduced, particularly when a large number of users from th e same I,AN access the video data. We design several video staging methods and evaluate their effectiveness in trading the disk bandwidth of a proxy s erver for the backbone WAN bandwidth. We also develop two heuristic algorit hms to solve the problem of designing a multiple video staging scheme for a proxy server with a given video access profile of a LAN. Our results demon strate that the proposed proxy-server-based approach provides an effective and scalable solution to the problem of the end-to-end,video delivery over WANs.