One of the major benefits of using an Access Gateway to protect Web resources is that it can cache the requested information and send it directly to the client browser rather than contacting the origin Web resource and waiting for the requested information to be sent. This can significantly accelerate access to the information.
The object cache on an Access Gateway is quite different from a browser’s cache, which all users access when they click the button and which can serve stale content that doesn’t accurately reflect the fresh content on the origin Web server.
The Access Gateway caching system uses a number of methods to ensure cache freshness. Most time-sensitive Web content is flagged by Webmasters in such a way that it cannot become stale unless a caching system ignores the Webmaster’s settings. The Access Gateway honors all flags that affect cache freshness, including Time to Expire, Don’t Cache, and Must Revalidate directives.
In addition, the Access Gateway can be fine-tuned for cache freshness in the following ways:
Accelerated checking of objects that have longer than desirable Time to Expire headers
Delayed checking of objects that have shorter than desirable Time to Expire headers
Checking for freshness of objects that do not include Time to Expire headers
The following sections describe the features available to fine-tune this process for your network: