Design and analysis of a variable bit rate caching algorithm for continuous media data

Abstract

In this paper, the problem of caching continuous media data in a (main) memory and disk caching system is addressed. Caching schemes can significantly reduce the load on the network as well as on the servers, also the retrieval of documents from the cache requires short response time. In interval-level caching algorithms, an interval of data between two adjacent streams is the basic caching entity. In this paper, we design a novel algorithm, referred to as variable bit rate caching (VBRC) algorithm, which belongs to the interval-level caching algorithms. The proposed VBRC algorithm can be used in the system for memory caching or disk caching. VBRC can handle variable retrieval bandwidth as well as constant retrieval bandwidth . In designing the VBRC algorithm, we propose the strategies of reducing the number of switching operation, which will probably cause discontinuity of retrieving data. Also, we propose a just-in-time scheme for resource allocation in our VBRC algorithm and show that the caching performance in comparison with the reservation scheme adopted in the resource-based caching (RBC) algorithm is significantly improved. Our simulation study compares the recent and most popular generalized interval caching, RBC, and VBRC, on several influencing factors such as cache space size, cache I/O bandwidth, request arrival rate, and percentage of requests for large documents, with respect to the byte hit ratio and the number of switching operations. The simulation result confirms our analysis. © 2007 Springer Science+Business Media, LLC.