On the Optimal Placement of Web Proxies in the Internet: The Linear Topology Bo Li, Xin Deng and Mordecai J. Golin Department of Computer Science, Hong Kong University of Science and Technology Clear Water Bay, Kowloon, Hong Kong. Tel: +852 2358 6976, Fax: +852 2358 1411 E-Mail: {bli, dengxin, golin }@cs.ust.hk Kazem Sohraby Bell Laboratories, Lucent Technologies 101 Crawfords Corner Road, Holmdel, NJ 07733, USA. E-Mail: sohraby@lucent.com Abstract Web caching or web proxy has been considered as the prime vehicle to cope with the ever-increasing demand for information retrieval over the Internet, WWW being a typical example. The existing work on web proxy has pri- marily focused on content based caching; relatively less attention has been given to the development of proper placement strategies for the potential web proxies in the Internet. This paper investigates the optimal placement policy of web proxies for a target web server in the Internet. The objective is to minimize the overall latency of searching the target web server subject to the network resources and traffic pattern. Specifically, we are interested in find- ing the optimal placement of multiple web proxies (m) among the potential sites (n) under a given traffic pattern. We model the problem as a Dynamic Programming problem, and we obtain an optimal solution for a linear array topology using O(n 2 m) time. Keywords Web caching, Proxy server, Dynamic Programming 1 INTRODUCTION We have witnessed an explosive growth in the use of World Wide Web (or web) in the past few years; there are many reasons behind this success, in particular, ease of use, the availability of standard tools for creating web documents and H. R. van As (ed.), High Performance Networking © Springer Science+Business Media New York 1998