Configuring BranchCache in Windows 7

BranchCache is a feature of Windows 7 that is most useful for companies with more than one branch. It provides a file caching service for professional network administrators. It works by enabling Windows servers to automatically retrieve and distribute local copies of files being accessed remotely by Windows 7 clients.
BranchCache can help increase the reponsiveness (fairly sure I've made that word up) of the network when using centralized applications in remote offices, and users can use the applications as if they were working on their local area network.
BranchCache also helps when using WAN bandwidth. When BranchCache is enabled, a copy of all files and data accessed from the company intranet and file servers is stored locally in the branch office. When another client using the same network requests the file, it can be downloaded from the local cache, without having to be downloaded over the WAN link.
In order to use BranchCache your computer must meet the following requirements:

• Client computers must be using Windows 7, with the BranchCache feature enabled. 
• Web and file servers must be using Windows Server 2008 with the BranchCache feature enabled. 

You can operate BranchCache in one of two modes:

• Distributed Cache - This mode uses peer-to-peer architecture, which is beneficial for branch offices that do not have a local server, distributed cache mode uses these processes to cache and retrieve data:
• The Windows 7 client connects to the server to request the file in the same way it would without BranchCache
•  The server authorizes and authenticates the client, and sends an identifier that is used by the client to search for the file. When a client attempts to retrieve a file for the first time, it is not stored locally on the network, so the client retrieves it directly from the content server and caches it. 
• When another client on the network requests the same data from the content server, it authenticates and authorizes the user in the same way it would without BranchCache. If this is successful metadata is sent over the same channel used for normal data. 
• The other client sends a request over the local network for the file by using the Web Services Discovery (WS-Discovery) multicast protocol. 
• The client that has cached the file sends it to the client requesting the file. The data is encrypted with a key made by the hashes sent by the content server with the file metadata. 
• The client then decrypts the data by computing the hashes on the blocks sent from the first client, and comparing them to the hashes on the the metadata sent by the content server. 
• Hosted Cache - uses a client/server architecture, client computers cache contents to another computer on the local network running Windows Server 2008. This is known as the hosted cache. Other clients on the network who need to access the same data can then get it straight from the hosted cache. The hosted cache computer can run Windows Server 2008 and other applications. Hosted cache mode uses these processes to cache and retrieve data:
• The Windows 7 client connects to the server and requests a file in the same way it would if BranchCache was not being used.
• The server authenticates and authorizes the user. If this is successful the metadata of the file is sent over the same channels that would be used for normal data. 
• The client uses the hashes in the metadata to search the file. .As this is the first time the file has been requested the file is not cached, and the client retrieves it directly from the content server. 
• The client establishes an SSL connection with the Hosted Cache server, and offers the content identifiers over this channel, which is encrypted
• The Hosted Cache server connects to the client and retrieves the blocks of data that it does not have cached
• When another client on the network requests the file, the content server again authenticates and authorizes the user, and sends content indentifiers. 
• The client uses the identifiers for requesting the data from the Hosted Cache server. The Hosted Cache server then encrypts the data and sends it to the client. The encryption comes from the hashes in the metadata sent by the content server.
•  The client decrypts the data and ensures that the block hashes sent by the content server in the metadata are identical, ensuring that the data has not changed. 

BranchCache is a passive cache, which means it only retrieves data when requested. This means that it does not increase utilization of the WAN. BranchCache improves the performance of applications that use HTTP and HTTPS (protocols used by web browsers) and SMB (the protocol used for sharing folders).

 To configure BranchCache, on the Windows 7 client you need to edit the group policy. You do this using the Microsoft Management Console (MMC).
Click start and type "group policy" in the search box, and click on "edit group policy"

In the sidebar of the management console, you need to select Computer Configuration, Administrative Templates, Network and then BranchCache.

 To turn on BranchCache, double click on the BranchCache option in the main window.

 You then need to select Enable at the top of the screen and click apply.


You can also configure whether you would like to turn on BranchCache in Hosted Cache mode or Distributed Cache mode by double clicking on the one you would like to enable. I am enabling Distributed Cache mode.

You can also configure BranchCache for network file. Enabling this allows you to configure the round trip network latency above which network files should be cached by client computers in the branch.

You can also configure the percentage of hard drive space from your computer you would like to use for caching.


 

And that's it. You now have BranchCache configured.