Placement of Web-Server Proxies with Consideration of Read and Update Operations on the Internet

This paper investigates the optimal placement of proxies of a Web server on the Internet, with the consideration of both read and update operations to the data on the Web server. We first study the problem of optimal placement of k proxies in a system to minimize the total access cost to the Web server. Then, for an unknown number of proxies, we find the optimal number of proxies required in the system. The problems are formulated by using the dynamic programming method and the optimal solutions are obtained. Simulations have been conducted to evaluate the performance of the proposed algorithms and to demonstrate how the effectiveness of proxy placement is affected by various factors, such as network traffic load, number of proxies, read–write ratio and proxy hit ratio.