What is BranchCache? BranchCache™ is a new feature in the Windows® 7 and Windows Server® 2008 R2 operating systems that caches content from file and Web servers on a wide area network (WAN) locally at a branch office.

BranchCache reduces WAN utilization and improves the performance of network connected applications for users in branch offices.

How Does It Work? When BranchCache is enabled, a copy of data from intranet web and file servers is stored locally. When another client at the branch office attempts to access the same content, the data is served from the branch office cache instead of from servers across the WAN.

BranchCache is a passive caching technology, and does not increase WAN utilization. BranchCache only retrieves data from a server when the client requests it and only caches read requests.

BranchCache is designed to prevent unauthorized access to content, and works seamlessly with encryption technologies such as IPsec, SSL, and SMB signing.

BranchCache can operate in two different modes:

Distributed Cache Mode - Windows 7 computers cache data and send it directly to other clients on demand. In this mode, improving performance is as easy as enabling BranchCache on your Windows 7 client and Windows Server 2008 R2 computers. This mode uses a peer-to-peer architecture, and does not require the use of any additional servers at the branch office. It is ideal when cost or physical security is a concern.

Hosted Cache Mode - Windows 7 client computers cache content to a Hosted Cache server, which is a computer on the local network running Windows Server 2008 R2. Any branch office clients who need the same content can then retrieve it directly from the Hosted Cache server. The Hosted Cache computer can run the Server Core installation option of Windows Server 2008 R2 and can also host other applications.

Key Solution Benefits Improved Performance

BranchCache improves the network responsiveness of applications that use either

HTTP/HTTPS or SMB protocols, such as web-based applications or those that utilize shared folders.

Seamless Security Integration

BranchCache works seamlessly with encryption technologies such as IPsec, SSL, and SMB signing to make securing BranchCache communications simple and efficient.

Reduced WAN Utilization

BranchCache stores and forwards data on the branch office local area network, which reduces the number of file transfers that occur across low bandwidth WAN links. Since BranchCache is a passive cache, it only transfers files across the WAN when a read request is made that doesn’t correspond to a file already stored in the branch.

Does Not Serve Stale Data

Every time a client issues a read request, BranchCache uses hashes to verify that the data cached at the branch office location is current with the data stored at the originating content server. If the data changes, new hashes are sent to the requester to ensure that no stale data is retrieved from the cache.

Simple Cost-Effective Solution

Implementing BranchCache can be as simple as enabling the BranchCache feature on Windows 7 clients and on Windows Server 2008 R2 servers. In Distributed Cache mode, there is no need for additional hardware or configuration. BranchCache is included as part of the Windows 7 and Windows Server 2008 R2 operating systems, so no additional software investments are necessary.

System Requirements Features List Resources

Distributed Mode

o Windows 7 Ultimate or Enterprise clients with BranchCache enabled

o Content servers running Windows Server 2008 R2 with BranchCache enabled

Hosted Mode

o Windows 7 Ultimate or Enterprise clients with BranchCache enabled

o Content servers running Windows Server 2008 R2 with BranchCache enabled

o Windows Server 2008 R2 Enterprise located at the branch office configured as a Hosted Cache

Flexible implementation in either Distributed Cache Mode or Hosted Cache Mode

Can be deployed without any additional hardware or software at the branch office

Improves the performance of applications that use either HTTP/HTTPS or SMB protocols

Passive cache that only retrieves data over the WAN when a read request is made

Easy to implement. Just enable via Group Policy for all Windows 7 clients and install the BranchCache feature on any Windows Server 2008 R2 content servers and the Hosted Cache server, if used

Works seamlessly with encryption technologies such as IPsec, SSL, and SMB signing

Does not interfere with file saves since BranchCache only operates on read requests

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