Understanding the performance of cooperative Web caching systems

Web caching has been recognized as an effective scheme to alleviate the service bottleneck and reduce the network traffic, thereby minimizing the user access latency on the Internet. To maximize the performance of caching, cache cooperation systems such as hierarchical, distributed and hybrid are employed. In this work, we first derive an analytical model to calculate the performance parameters for the aforementioned three caching systems. We then test these systems on a Web cache simulator. Results show that the hybrid system is very competitive in terms of the hit ratio and the bandwidth usage compared to the distributed system and hierarchical system, respectively. On the other hand, the hybrid system gives the optimal results in terms of latency and the number of hops.