Performance comparison of alternative Web caching techniques

Web caching is a popular technique to improve the performance and scalability of the Web by increasing document availability and enabling download sharing. Distributed cache cooperation, a mechanism for sharing documents between caches, can further improve performance by providing a shared cache to a large user population. Layer 5 switching-based transparent Web caching schemes intercept HTTP requests and redirect requests according to their contents. This technique not only makes the deployment and configuration of the caching system easier, but also improves its performance by redirecting non-cacheable HTTP requests to bypass cache servers. In this paper, we compare the performance of a number of cooperative (ICP and Cache Digest) and transparent (L5 transparent Web caching and LB-L5) Web caching techniques. We conduct a number of simulation experiments under different HTTP request intensities, network link delays and populations of cooperating cache servers. The relative merits of the different schemes are reported.