A unified algorithm for cache replacement and consistency in web proxy servers

Caching of Web documents improves the response time perceived by the clients. Cache replacement algorithms play a central role in the response time reduction by selecting a subset of documents for caching so that an appropriate performance metric is maximized. At the same time, the cache must take extra steps to guarantee some form of consistency of the cached data. Cache consistency algorithms enforce appropriate guarantees about the staleness of documents it stores. Most of the published work on Web cache design either considers cache consistency algorithms separately from cache replacement algorithms or concentrates only on studying one of the two. We argue that cache performance can be improved by integrating cache replacement and consistency algorithms. We present an unified algorithm LNC-R-W3-U. Using trace-based experiments, we demonstrate that LNC-R-W3-U achieves performance comparable (and often superior) to most of the published cache replacement algorithms and at the same time significantly reduces the staleness of the cached documents.