Web Caching: Reducing Network Traffic

On the World Wide Web, speed and efficiency are vital. Users have little patience for slow Web pages, while network administrators want to make the most of their available bandwidth. A properly designed Web cache reduces network traffic and improves access times to popular Web sites - a boon to network administrators and web users alike. This text provides the technical information needed to design, deploy, and operate an effective Web caching service. It starts with the basics of how Web caching works, from the HTTP headers that govern cachability to cache validation and replacement algorithms. Topics covered in this guide include: designing an effective cache solution; configuring Web browsers to use a cache; setting up a collection of caches that can talk to each other; configuring an interception cache or proxy; monitoring and fine-tuning the performance of a cache; configuring Web servers to co-operate with Web caches; and benchmarking cache products. The book also covers the important political aspects of Web caching, including privacy, intellectual property, and security issues.

Table of Contents:
Preface. Chapter 1. Introduction Web Architecture Web Transport Protocols Why Cache the Web? Why Not Cache the Web? Types of Web Caches Caching Proxy Features Meshes, Clusters, and Hierarchies Products. Chapter 2. How Web Caching Works HTTP Requests Is It Cachable? Hits, Misses, and Freshness Hit Ratios Validation Forcing a Cache to Refresh Cache Replacement. Chapter 3. Politics of Web Caching Privacy Request Blocking Copyright Offensive Content Dynamic Web Pages Content Integrity Cache Busting and Server Busting Advertising Trust Effects of Proxies. Chapter 4. Configuring Cache Clients Proxy Addresses Manual Proxy Configuration Proxy Auto-Configuration Script Web Proxy Auto-Discovery Other Configuration Options The Bottom Line. Chapter 5. Interception Proxying and Caching Overview The IP Layer: Routing The TCP Layer: Ports and Delivery The Application Layer: HTTP Debugging Interception Issues To Intercept or Not To Intercept. Chapter 6. Configuring Servers to Work with Caches Important HTTP Headers Being Cache-Friendly Being Cache-Unfriendly Other Issues for Content Providers. Chapter 7. Cache Hierarchies How Hierarchies Work Why Join a Hierarchy? Why Not Join a Hierarchy? Optimizing Hierarchies. Chapter 8. Intercache Protocols ICP CARP HTCP Cache Digests Which Protocol to Use. Chapter 9. Cache Clusters The Hot Spare Throughput and Load Sharing Bandwidth. Chapter 10. Design Considerations for Caching Services Appliance or Software Solution Disk Space Memory Network Interfaces Operating Systems High Availability Intercepting Traffic Load Sharing Location Using a Hierarchy. Chapter 11. Monitoring the Health of Your Caches What to Monitor? Monitoring Tools. Chapter 12. Benchmarking Proxy Caches Metrics Performance Bottlenecks Benchmarking Tools Benchmarking Gotchas How to Benchmark a Proxy Cache Sample Benchmark Results Appendix A. Analysis of Production Cache Trace Data Appendix B. Internet Cache Protocol Appendix C. Cache Array Routing Protocol Appendix D. Hypertext Caching Protocol Appendix E. Cache Digests Appendix F. HTTP Status Codes Appendix G. U.S.C. 17 Sec. 512. Limitations on Liability Relating to Material Online Appendix H. List of Acronyms Glossary Index

About the Author :
Duane Wessels discovered Unix and the Internet as an undergraduate student studying physics at Washington State University. After playing system administrator for a few years, he moved to Boulder, Colorado, to attend graduate school. In late 1994, he joined the Harvest project, where he worked on searching, indexing and caching. From 1996 until 2000, he was co-principal investigator of the NLANR Information Resource Caching project (IRCache), which operated several large caches throughout the U.S. During this time, he and others developed and supported the Squid caching proxy. In 1999, his team organized the first "Cache-Off," a performance benchmarking event for caching proxies. Currently, he is co-owner and president of The Measurement Factory, Inc., a company that specializes in evaluating the performance and behavior of HTTP-aware devices. Like many other Colorado residents, he enjoys hiking, bicycling, and snowboarding.

Review :
'It provides a good general introduction to caching solution. If all web sites follwed the suggestions on cache-friendliness then the web could be a much faster and more efficient place.' - Andrew Cormack, new@UK, December 2001