Improving the Effectiveness of Web Caching

Abstract

The bandwidth demands on the (World-Wide) Web continue to grow at an exponential rate. It is thus becoming crucial to provide solutions improving the Web latency. In that framework, the most promising low cost solution lies in the use of caches at the level of the clients, network and servers. Caching effectiveness then relies upon adequate cache management so as to keep in the cache the Web objects that are the most likely to be re-accessed. However, the effectiveness of a single cache remains poor as it is in general no higher than 40%. One way to further improve caching effectiveness is thus to make caches cooperate so as to increase the probability of retrieving an object at the caching level. The cache cooperation protocol must then be such that it induces a negligible load for the network and cooperating caches.

This paper presents our solutions to improving the effectiveness of Web caching concerning both cache management and cache cooperation. Regarding cache management, we propose two novel algorithms that exploit the latest results about Web usage, enabling us to undertake replacement decisions that are more accurate than the one taken by existing algorithms. From the standpoint of cooperating caches, we propose a cooperation protocol, which minimizes the associated network bandwidth, processing load, and storage consumption among caches.