Proxy caching that estimates page load delays

Do users wait less if proxy caches incorporate estimates of the current network conditions into document replacement algorithms? To answer this, we explore two new caching algorithms: (1) keep in the cache documents that take the longest to retrieve; and (2) use a hybrid of several factors, trying to keep in the cache documents from servers that take a long time to connect to, that must be loaded over the slowest Internet links, that have been referenced the most frequently, and that are small. The algorithms work by estimating the Web page download delays or proxy-to-Web server bandwidth using recent page fetches. The new algorithms are compared to the best three existing policies—LRU, LFU, and SIZE—using three measures-user response time and ability to minimize Web server loads and network bandwidth consumed—on workloads from Virginia Tech and Boston University.