The Web proxy cache placement problem is often formulated as a classical optimization problem: place N proxies within an internetwork so as to minimize the average user response time for retrieving Web objects. Approaches to this problem in the literature include graph theoretic approaches, combinatorial approaches, dynamic programming approaches, and vector quantization approaches. In this paper, we tackle the cache placement problem using packet-level ns2 network simulations. There are three main conclusions from our study. First, network-level effects (e.g., TCP dynamics, network congestion) can have a significant impact on user-level Web performance, and must not be overlooked when optimizing Web proxy cache placement. Second, cache filter effects can have a pronounced impact on the overall structure of an optimal caching solution. Third, small perturbations to the Web workload can produce quite different solutions for the optimal cache placement problem. This implies that robust ...
Gwen Houtzager, Carey L. Williamson