Sebastopol, CA--There are many arguments for the practice of web
caching, and it seems, almost as many against. In his just-released
book, Web
Caching (O'Reilly, US $39.95), Duane Wessels explains the
theory and benefits of web caching. He also explores the politics that
surround web caching, touching on the fears of security, privacy, and
copyright infringement that accompany the topic. Rather than dismissing
these fears outright, Wessels examines the thinking behind them, and
provides insightful solutions in a way that administrators will
thoroughly understand the issues and the choices they have for dealing
with them. As Wessels shows, web caching, when properly done, can be a
boon to network administrators and users alike.
The practice of web caching has exploded within recent years. It is
estimated that between 40,000 and 60,000 organizations are operating
web caches; among these two-thirds are using open source caching
software. Types of web caches range from familiar browser caches to
caching proxies that serve many different users at once, all the way to
clusters of caches that talk to each other.
"Web caching is important for a number of reasons," Wessels explains.
"First of all, it saves organizations time and money. People that use
web caches spend less time waiting for pages to download. Web caching
improves the utilization of network connections so organizations that
pay for bandwidth get more for their money. Many caching proxies also
have features that protect users privacy and improve network security."
Web Caching
provides network administrators with all the information
they will need to design, implement, and tune a web cache system. The
book lays out the basics of cache design, including protocols and
operation, and describes implementation issues and performance
monitoring. Also discussed in full detail is Squid, one of the most
popular open source caching programs.
Topics covered in Web Caching 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
"Web caching is as important now as it ever has been," Wessels says.
"There has been a lot of buzz recently about Content Distribution
Networks. These CDNs, however, only improve the performance of content
providers who can afford the high subscription fees. A web cache
located on an organization's network improves the performance of all
sites visited by users. Furthermore, CDNs do not offer any of the
privacy and security features that caching proxies do."
According to Wessels,
Web Caching is
relevant to administrators who are responsible for the day-to-day operation of
one or more web caches, such as administrators for ISPs, corporations, or
educational institutions. Content providers and developers should also be
knowledgeable about the workings of web caches. For example, anyone
developing an application that uses HTTP will need to understand how
web caching works, as many of their users are behind firewalls and web
caches. As Wessels explains, "A significant amount of HTTP traffic is
automatically intercepted and sent to web caches. Failure to take
caching issues into consideration may adversely affect the operation of
your application."
Online Resources:
Web
Caching
By Duane Wessels
July 2001
ISBN 1-59692-536-X, 300 pages, $39.95 (US)
order@oreilly.com
