User manual

Chapter 3: Qube 3 Services
60 Cobalt Qube 3 User Manual
Web Caching
Web Caching is available on the Qube 3 Business Edition and Professional
Edition only.
The Qube 3 offers a caching feature. When the caching feature is enabled, the
Qube 3 acts as a caching proxy server for Web clients.
Web cache servers are network servers that store frequently used content, such as
Web pages and graphics, closer to the requesting clients so that subsequent
accesses are served from the local server. It works as follows: when the browser
requests a Web page from the network, the Web cache server intercepts the
request. If the cache server has an up-to-date copy, it returns the copy to the client
immediately. If the cache does not have a copy, it fetches one from the source of
the content, saves a copy for future requests and returns the result to the client.
The key benefits of caching are:
• Faster response times from the Web. Once an object is cached, subsequent
requests by a client for that object do not have to access the public Internet.
Cached objects are held much closer to the client making the request and are
retrieved much more quickly.
• Cost savings. In some locations (for example, in Europe, Asia and
Australia), a client is charged a fee for each megabyte (MB) of data
transferred. By having the object cached locally and not having to transfer it
over the Internet again, a client avoids extra charges.
• Reduced network bandwidth requirements. Having an object cached
locally means that content does not have to travel over congested wide area
networks (WANs), thus conserving bandwidth.
For more information on Caching, see “Web Caching” on page 144.
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Note: The Web Caching feature on your Qube 3 relies on the Basic
Firewall feature to operate. If you enable the Web Caching feature,
the Basic Firewall feature is enabled automatically.
If you disable the Basic Firewall feature, the Web Caching feature
is still enabled but will not function. To ensure that the Web
Caching feature is functioning, re-enable the Basic Firewall feature.
For more information, see “Basic Firewall” on page 57.