Site-Based Approach to Web Cache Design

W eb caching is widely viewed as an effective way to improve Internet performance. Web cache servers temporarily store Web documents. Because cache servers are typically located near the clients, using them reduces retrieval latencies and the number of requests reaching Web servers, thus reducing overall network activity. Most Web cache servers make cache decisions based on document names or URLs. Although it seems natural to keep statistics on individual documents, it is not the only option. We propose a new basis for caching decisions: a site-based approach. With this approach, cache servers consider the Web site a document belongs to, rather than the document itself. Depending on the application, a site-based approach can offer many benefits, including proxy load reduction, higher prediction and hit ratios, and fewer memory requirements. When we first proposed this idea in 1999,1 we were unaware of any previous related work. However, we have since found that some researchers implicitly applied a site-based approach, though they did not focus on it. Here, we describe the site-based approach and consolidate previous efforts, discussing both the approach’s benefits and its successful applications.