A redundant hierarchical structure for a distributed continuous media server

Abstract

The growing number of digital audio and video repositories has resulted in a desperate need for effective techniques to deliver data to users in a timely manner. Due to geographical distribution of users, it is not cost effective to have a centralized media server. In this paper, we investigate issues involved in the design of a distributed video server (DVS) to support movie-on-demand (MOD) application. We propose a redundant hierarchical (RedHi) architecture for DVS where the nodes are continuous media servers and the edges are dedicated network lines. With RedHi, each node has two or more parents. We show that the redundant links in RedHi yield a more reliable and efficient system. Our simulation results demonstrate that RedHi can tolerate a single link failure with no degradation in performance while with pure hierarchy almost 2.5% of requests are rejected due to the failure. In normal mode of operation, RedHi outperforms pure hierarchy significantly (160% improvement on the average when counting the number of rejections). In the context of RedHi, we also propose and evaluate alternative object management policies, and load balancing heuristics.

This research has been funded by the Integrated Media Systems Center, a National Science Foundation Engineering Research Center (NSF grant EEC-9529152) with additional support from the Annenberg Center for Communication at the University of Southern California and the California Trade and Commerce Agency.