Microsoft QLF-00195 manual Transparent Caching

Windows 7 for IT Pros: Make People Productive Anywhere

Access Information from Anywhere

BranchCache supports the same network protocols that are commonly used in enterprises—HTTP(S) and SMB—so that any applications based on these network protocols will automatically benefit from the technology. Examples of these applications include Microsoft Office SharePoint 2007, Internet Explorer, CopyFile, and others. For example, Windows Media Player uses the HTTP protocol so internal training videos can be cached and viewed more efficiently by branch office users. BranchCache also supports network security protocols (such as SSL and IPSec), helping ensure that only authorized PCs can access requested data.

To implement BranchCache, you need to install Windows Server 2008 R2 on the remote file servers, Web servers, and optionally the branch office server on which the cache is hosted.

Transparent Caching

Before Windows 7, client PCs always retrieved the file from the server computer to open a file across a slow network—even if the client PC had recently read the file. With transparent caching in Windows 7, client PCs cache remote files more frequently, which helps reduce the number of times a client PC has to retrieve the same data from a server computer.

The first time a user opens a file in a shared folder, Windows 7 reads the file from the server computer and then stores it in a cache on the PC’s hard disk. For any subsequent times a user reads the same file, Windows 7 retrieves the cached file from the hard disk instead of the server computer. Windows 7 always contacts the server computer to make sure the cached copy is up-to-date. The cache is never accessed if the server computer is unavailable, and updates to the file are always written directly to the server computer.

By default, transparent caching is not enabled on fast networks. You can use Group Policy to enable transparent caching to improve the efficiency of the cache and to save disk space on the client. You can also configure the amount of disk space the cache uses and prevent specific file types from being synchronized.

As the feature name implies, transparent caching is invisible to users, which makes it seem more like they are on the same LAN as the server computer. In addition, transparent caching helps reduce bandwidth utilization across WAN links.

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