A hierarchical network storage architecture for video-on-demand services

The advances in cable TV networks and multimedia technologies have open the possibilities for network/service/content providers to offer residential customers with video-on-demand services. However, the mass storage system used in supporting such services demands proper organization and management. 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 the second highest 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 number of programs stored in the two service centers (LSC and LCSC) and the number 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.