Modeling the Caching Effect in Continuous Media Servers

Caching is one of the most important schemes for improving the performance of continuous media servers. Continuous object caching enables a server to support more clients simultaneously since it reduces the disk load imposed at each round. However, without a quantative analysis of the disk load reduction induced by caching, the caching effect can not be reflected in the admission control scheme, which limits the number of simultaneous clients serviced. In this paper, we define a performance metric for caching scheme in the continuous media server, define an optimal caching, formalize three heuristic block replacement model and propose a novel near optimal caching scheme. For quantative analysis of the proposed scheme we also propose a probabilistic model of the caching effect in a continuous media server. The proposed model enables the development of efficient statistical admission control algorithms that can increase the number of clients serviced simultaneously. To show the potential of the model, we present a simple example of a statistical admission control algorithm and demonstrate the performance enhancement resulting from the use of the proposed model.