Fast hierarchical FLP model for VoD server deployment

Video on demand (VoD) is an important service for the next generation networks. In the VoD servers. it is not efficient to preserve all copies of videos. The videos could be divided into the popular ones and less popular ones according to their playing ratios. Since the popular videos are accessed frequently, they should be placed on every server, the cache server. Oppositely, the unpopular one are placed on the central server. In this work, we propose a detailed mathematical model for the hierarchical facility location problem (FLP) encountered in the cache/central server deployment. A linear model for hierarchical FLP is presented and could obtain the feasible solution easily. The experimental results demonstrate the effectiveness.