Scheduling Video Streams in a Large-Scale Video-On-Demand Server

This paper addresses the design problems concerning a large scale parallel video on demand server that consists of multiple clusters of nodes connected by a high performance interconnection network In order to e ciently control the ow of video streams we propose two scheduling algorithms for data retrieval and communica tion First we present a disk scheduling algorithm called round scheduling which fully utilizes disk bandwidth minimizing the disk idle time while the server retrieves data blocks Second a communication scheduling algorithm is developed to guaran tee con ict free communication over the multistage interconnection network that is topologically equivalent to the Omega network We also show some simulation re sults on the server con guration Analysis of tradeo s between the server utilization and the startup latency helps to determine the proper number and size of server clusters for a set of given nodes