A scalable architecture for cooperative Web caching

Cooperative Web caching is the most common solution for augmenting the low cache hit rates due to single proxies. However, both purely hierarchical and flat architectures suffer from scalability problems due to cooperation protocol overheads. We present a new cooperative architecture that organizes cache servers in well connected clusters and implements a novel cooperation model based on a two-tier lookup process. The experimental results carried out on a working prototype show that the proposed architecture is really effective in supporting cooperative Web caching because it guarantees cache hit rates comparable to those of the most performing architectures and it reduces cooperation overhead at a small fraction of that of other protocols.