Fragmental Proxy Caching for Streaming Multimedia Objects

In this paper, a fragmental proxy-caching scheme that efficiently manages the streaming multimedia data in proxy cache is proposed to improve the quality of streaming multimedia services. The novel data-fragmentation method in this scheme not only provides finer granularity caching units to allow more effective cache replacement, but also offers a unique and natural way of handling the interactive VCR functions in the proxy-caching environment. Furthermore, a cache-replacement scheme, based on user request arrival rates for different multimedia objects and the playback rates of these objects, is proposed to address the drawbacks in existing cache-replacement schemes, most of which consider only the user access frequencies in their cache-replacement decisions. In this cache-replacement scheme, a sliding history window is employed to monitor the dynamic user request arrivals, and a tunable-victimization procedure is used to provide an excellent method of managing the cached multimedia data in accordance with different quality-of-service requirements of the streaming multimedia applications. Performance studies demonstrate that the fragmental proxy-caching scheme significantly outperforms other caching schemes, in terms of byte-hit ratio and the number of delayed starts and can be tuned to either maximize the byte-hit ratio or minimize the number of delayed starts