A Hierarchical Network Storage Architecture for Video-on-Demand Services

Recent advances in Cable TV networks and multimedia technologies open the possibilities for network/service/content providers to offer residential customers with video-on-demand services. However, the mass storage system in supporting such services demands proper organization and management. In this paper we present a three-level hierarchical network storage architecture for the video-on-demand storage system. At the first-level (Local Service Center, LSC) a limited number of programs with high viewing probabilities are stored; while at the second-level (Local Central Service Center, LCSC) a few programs with second high viewing probabilities are stored. The third-level (Central Service Center, CSC) contains all programs provided in the system. Based on this architecture and the program viewing probability distribution function, we use a minimum-cost function to find out the numbers of programs stored in the two service centers (LSC and LCSC) and numbers of links among these three service centers. We also describe two program reallocation algorithms which swap programs between service centers according to the change in user request patterns.