A hash-based collaborative transcoding proxy system

Abstract

With the ever increasing wireless client population, the Internet client devices have become highly heterogeneous. Transcoding is used to adapt web objects to suit diverse devices. In this paper, a hash-based collaborative transcoding proxy system is proposed, which aims to improve the system performance in two aspects, caching efficiency and workload balancing. This system employs a hashed-based object caching strategy, which optimizes the cache storage utilization by removing redundant objects scattering in different locations of the overall system cache. In addition, a cache replacement algorithm deployed at the transcoding proxy is examined. A simple hash-based workload distribution strategy is also proposed to share the expensive transcoding load among the various proxies. This strategy performs well with balanced hash function. With unbalanced hash function, satisfactory load sharing is achieved by an optimized strategy, which allows the overloaded proxy to alleviate its load by outsourcing some excessive transcoding tasks to its less overloaded neighbors. An event-driven simulation is conducted to evaluate the system performance, and our results show that the proposed system outperforms existing methods in terms of throughput and response time. © 2004 Elsevier B.V. All rights reserved.