A Viability Analysis of Cooperative Proxy Caching

A cooperating proxy cache is a group of Web proxy caches that share their cached objects. This paper models the response time speedup for several cooperative organizations and evaluates the viability of proxy cooperation based upon empirically determined hit rates and measured Web response times. The models account for overhead of different discovery mechanisms (e.g. ICP or metadata directory) and examine how the trade-off between discovery overhead and discovery success affects performance. We find proxy cooperation to be only marginally viable if the sole criteria is average response time. However, proxy cooperation can reduce the variability in response time and the number of pathologically long delays. Moreover, cooperation offers a means of avoiding network congestion, thereby improving overall throughput. Keywords—Web, proxy, cache, hierarchy, mesh, cooperative proxy caching