Cache Overview

The Forefront TMG Web proxy implements a cache of frequently requested objects to improve network performance. You can configure the cache to ensure that it contains the data that is most frequently used by users in your organization or accessed by your Internet clients.

Forefront TMG caching features include:

• Forward caching. When Forefront TMG allows internal clients to send outgoing Web requests to external Web servers, Forefront TMG can be configured to maintain a centralized cache of frequently requested Web objects that are retrieved from the external Web servers. These cached objects can be accessed by any client Web browser. Objects served from a disk cache require significantly less processing than objects served from the Internet. This improves client browser performance, decreases user response time, and reduces bandwidth consumption on your Internet connection.
• Reverse caching. Forefront TMG can be deployed in front of Web servers that it publishes, and can cache the content from the published Web servers, thereby improving their performance and accessibility. When incoming Web requests arrive, Forefront TMG can impersonate a Web server to the outside world, fulfilling client requests for Web content from its cache. Forefront TMG forwards requests to the Web server only when the requests cannot be served from its cache. All Forefront TMG caching features are applicable for the content on published servers.
• Content download jobs. You can configure Forefront TMG to download frequently requested content from the Internet to its cache according to predefined schedules using the Microsoft® Forefront TMG Job Scheduler service.
• Distributed caching. When you set up an array of multiple Forefront TMG computers (not supported in Forefront TMG Medium Business Edition), you benefit from distributed caching. Forefront TMG uses the Cache Array Routing Protocol (CARP) to enable multiple Forefront TMG computers to be arrayed as a single logical cache.
• Hierarchical caching. Forefront TMG further extends distributed caching by allowing you to set up a hierarchy of caches, chaining together arrays of Forefront TMG computers, so that clients can access objects from the cache geographically nearest them.

For more information about the Forefront TMG cache, see About the Forefront TMG Cache.

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Build date: 11/30/2009