For Windows Server® 2008 R2, BranchCache was introduced tohelp you reduce WAN bandwidth usage by client computers that accessed content,such as Web pages and file shares, on content servers in remote main offices.
With that release, as with BranchCache in Windows Server2012, you can deploy BranchCache in two modes - distributed cache mode andhosted cache mode.
With distributed cache mode, client computers retrievecontent from the main office content servers and then cache the content toshare it with other clients in the same branch office.
With hosted cache mode, a server in the branch office -called a hosted cache server - is used as a central cache for the branch. Afterretrieving content from the main office content server, client computers thenstore the content on the hosted cache server, which in turn shares the contentwith other client computers in the branch office.
For Windows Server 2012, BranchCache functions much the sameway, however deploying hosted cache mode is significantly easier, thanks toimprovements and new features provided by the BranchCache team for thisrelease.
Previously, hosted cache servers were required to have aserver certificate that was issued by a certification authority (CA) thatclient computers at the office location trusted. Deploying a public keyinfrastructure with one or more CAs is complex and expensive, and thisrequirement is now removed, because BranchCache security is improved with dataencryption and other technologies. So you don't need to deploy a CA justbecause you want to deploy BranchCache in hosted cache mode.
A terrific new feature for BranchCache clients that arerunning Windows® 8 Release Preview is the ability to self-configure for theBranchCache mode that is appropriate for the branch office in which the clientcomputer is installed. Simply by configuring one Group Policy setting, you canconfigure BranchCache clients to search for one or more hosted cache servers inthe branch office. If client computers find one or more hosted cache servers -which in this context are called "service connection points" - theyself-configure BranchCache for hosted cache server mode. If they don't find ahosted cache server, the client computers self-configure BranchCache fordistributed cache mode.
This BranchCache Group Policy setting, in case you'resetting up a test lab for BranchCache in Windows Server 2012, is called"Enable Automatic Hosted Cache Discovery by Service Connection Point."
"Configure Hosted Cache Servers" is a new GroupPolicy setting that you can also use when deploying BranchCache in hosted cachemode. With this setting, you can enter the computer names of the hosted cacheservers that are available to client computers in the branch office. If you usethis setting, client computers don't need to search for hosted cache serversbecause they already have the server names.
Another great new feature for BranchCache allows those ofyou with large branch offices to deploy more than one hosted cache server ineach branch office. In the previous version of BranchCache, you were able todeploy only one hosted cache server per office location. Windows Server 2012provides the ability to scale hosted cache mode deployments for offices of anysize by allowing you to deploy as many hosted cache servers as are needed at alocation.
So the simple overview of deploying BranchCache hosted cachemode in Windows Server 2012 is this: install your content servers in your main office or cloud datacenter,automatically configure clients using Group Policy, and install the BranchCachefeature on the computers that you want to use as hosted cache servers, then run one Windows PowerShell command to configure the computers as hosted cache servers. Nolimitations on the number of hosted cache servers per branch, and norequirement to design and deploy a public key infrastructure with certificates.
For more information about additional great new features inBranchCache, you might want to take a look at the topic What's New inBranchCache, at http://technet.microsoft.com/en-us/library/jj127252.