Web Caching and Replication

Chapter 11. Replacement Policy

Any proxy faces several policy decisions. One of them is to decide which objects, if any, to evict from the cache when no space is available to store additional objects. This chapter discusses various options for this policy decision.

The strategy used for eviction decisions is often referred to as a replacement policy. Traditionally, research in the area of caching has been almost synonymous with studying cache replacement policies (the decision on what to store was usually simple: store everything, assuming it is cacheable). Much work on proxy Web caching has also been devoted to clever replacement policies and their effects on hit rates. However, we argue that replacement policies are not the limiting factor ...