Synopses & Reviews
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.
Web Caching hands you all the technical information you need 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 book 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 cooperate with web caches
- Benchmarking cache products
The book also covers the important political aspects of web caching, including privacy, intellectual property, and security issues.
Internet service providers, large corporations, or educational institutions--in short, any network that provides connectivity to a wide variety of users--can reap enormous benefit from running a well-tuned web caching service. Web Caching shows you how to do it right.
Synopsis
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.Web Caching hands you all the technical information you need 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 book 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 cooperate with web caches
- Benchmarking cache products
The book also covers the important political aspects of web caching, including privacy, intellectual property, and security issues.Internet service providers, large corporations, or educational institutions--in short, any network that provides connectivity to a wide variety of users--can reap enormous benefit from running a well-tuned web caching service.
Web Caching shows you how to do it right.
About the Author
Duane Wessels became interested in web caching in 1994 as a topic for his master's thesis in telecommunications at the University of Colorado, Boulder. He worked with members of the Harvest research project to develop web caching software. After the departure of other members to industry jobs, he continued the software development under the name Squid. Another significant part of Duane's research with the National Laboratory for Applied Network Research has been the operation of 6 to 8 large caches throughout the U.S. These caches receive requests from hundreds of other caches, all connected in a "global cache mesh."
Table of Contents
Preface; Audience; What You Will and Won't Find Here; Caching Resources; Conventions Used in This Book; How To Contact Us; Acknowledgments; Chapter 1: Introduction; 1.1 Web Architecture; 1.2 Web Transport Protocols; 1.3 Why Cache the Web?; 1.4 Why Not Cache the Web?; 1.5 Types of Web Caches; 1.6 Caching Proxy Features; 1.7 Meshes, Clusters, and Hierarchies; 1.8 Products; Chapter 2: How Web Caching Works; 2.1 HTTP Requests; 2.2 Is It Cachable?; 2.3 Hits, Misses, and Freshness; 2.4 Hit Ratios; 2.5 Validation; 2.6 Forcing a Cache to Refresh; 2.7 Cache Replacement; Chapter 3: Politics of Web Caching; 3.1 Privacy; 3.2 Request Blocking; 3.3 Copyright; 3.4 Offensive Content; 3.5 Dynamic Web Pages; 3.6 Content Integrity; 3.7 Cache Busting and Server Busting; 3.8 Advertising; 3.9 Trust; 3.10 Effects of Proxies; Chapter 4: Configuring Cache Clients; 4.1 Proxy Addresses; 4.2 Manual Proxy Configuration; 4.3 Proxy Auto-Configuration Script; 4.4 Web Proxy Auto-Discovery; 4.5 Other Configuration Options; 4.6 The Bottom Line; Chapter 5: Interception Proxying and Caching; 5.1 Overview; 5.2 The IP Layer: Routing; 5.3 The TCP Layer: Ports and Delivery; 5.4 The Application Layer: HTTP; 5.5 Debugging Interception; 5.6 Issues; 5.7 To Intercept or Not To Intercept; Chapter 6: Configuring Servers to Work with Caches; 6.1 Important HTTP Headers; 6.2 Being Cache-Friendly; 6.3 Being Cache-Unfriendly; 6.4 Other Issues for Content Providers; Chapter 7: Cache Hierarchies; 7.1 How Hierarchies Work; 7.2 Why Join a Hierarchy?; 7.3 Why Not Join a Hierarchy?; 7.4 Optimizing Hierarchies; Chapter 8: Intercache Protocols; 8.1 ICP; 8.2 CARP; 8.3 HTCP; 8.4 Cache Digests; 8.5 Which Protocol to Use; Chapter 9: Cache Clusters; 9.1 The Hot Spare; 9.2 Throughput and Load Sharing; 9.3 Bandwidth; Chapter 10: Design Considerations for Caching Services; 10.1 Appliance or Software Solution; 10.2 Disk Space; 10.3 Memory; 10.4 Network Interfaces; 10.5 Operating Systems; 10.6 High Availability; 10.7 Intercepting Traffic; 10.8 Load Sharing; 10.9 Location; 10.10 Using a Hierarchy; Chapter 11: Monitoring the Health of Your Caches; 11.1 What to Monitor?; 11.2 Monitoring Tools; Chapter 12: Benchmarking Proxy Caches; 12.1 Metrics; 12.2 Performance Bottlenecks; 12.3 Benchmarking Tools; 12.4 Benchmarking Gotchas; 12.5 How to Benchmark a Proxy Cache; 12.6 Sample Benchmark Results; Analysis of Production Cache Trace Data; Reply and Object Sizes; Content Types; HTTP Headers; Protocols; Port Numbers; Popularity; Cachability; Service Times; Hit Ratios; Object Life Cycle; Request Methods; Reply Status Code; Internet Cache Protocol; ICPv2 Message Format; Opcodes; Option Flags; Experimental Features; Cache Array Routing Protocol; Membership Table; Routing Function; Examples; Hypertext Caching Protocol; Message Format and Magic Constants; HTCP Data Types; HTCP Opcodes; Cache Digests; The Cache Digest Implementation; Message Format; An Example; HTTP Status Codes; 1xx Intermediate Status; 2xx Successful Response; 3xx Redirects; 4xx Request Errors; 5xx Server Errors; U.S.C. 17 Sec. 512. Limitations on Liability Relating to Material Online; List of Acronyms; Bibliography; Books and Articles; Request For Comments; Colophon;