Scalable multimedia servers

In large-scale multimedia applications, such as video on demand (VoD), interactive television (ITV), and Web browsers, the sheer number of users and the data size of the systems exacerbate the difficulty of supporting continuous-time presentation. For example, a single video stream requires between 1.5 and 6 Mbps of bandwidth. At 6 Mbps, the typical rate required for ITV, even the 100-stream servers deployed in a number of small-scale ITV trials must support a throughput in excess of 70 Mbytes per second. Yet, most conventional network data servers are limited to a throughput of well under 10 Mbytes per second. For example, a 1,000-stream server, which is the minimum considered for production ITV systems, requires parallel-processing systems with 15 or more nodes. All nodes must be able to access the same video data simultaneously. The need for a scalable multimedia-server solution is obvious