For Windows Server® 2008 R2, BranchCache was introduced to
help 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 Server
2012, you can deploy BranchCache in two modes – distributed cache mode and
hosted cache mode.
With distributed cache mode, client computers retrieve
content from the main office content servers and then cache the content to
share 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. After
retrieving content from the main office content server, client computers then
store the content on the hosted cache server, which in turn shares the content
with other client computers in the branch office.
For Windows Server 2012, BranchCache functions much the same
way, however deploying hosted cache mode is significantly easier, thanks to
improvements and new features provided by the BranchCache team for this
Previously, hosted cache servers were required to have a
server certificate that was issued by a certification authority (CA) that
client computers at the office location trusted. Deploying a public key
infrastructure with one or more CAs is complex and expensive, and this
requirement is now removed, because BranchCache security is improved with data
encryption and other technologies. So you don't need to deploy a CA just
because you want to deploy BranchCache in hosted cache mode.
A terrific new feature for BranchCache clients that are
running Windows® 8 Release Preview is the ability to self-configure for the
BranchCache mode that is appropriate for the branch office in which the client
computer is installed. Simply by configuring one Group Policy setting, you can
configure BranchCache clients to search for one or more hosted cache servers in
the branch office. If client computers find one or more hosted cache servers –
which in this context are called "service connection points" – they
self-configure BranchCache for hosted cache server mode. If they don't find a
hosted cache server, the client computers self-configure BranchCache for
distributed cache mode.
This BranchCache Group Policy setting, in case you're
setting 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 Group
Policy setting that you can also use when deploying BranchCache in hosted cache
mode. With this setting, you can enter the computer names of the hosted cache
servers that are available to client computers in the branch office. If you use
this setting, client computers don't need to search for hosted cache servers
because they already have the server names.
Another great new feature for BranchCache allows those of
you with large branch offices to deploy more than one hosted cache server in
each branch office. In the previous version of BranchCache, you were able to
deploy only one hosted cache server per office location. Windows Server 2012
provides the ability to scale hosted cache mode deployments for offices of any
size by allowing you to deploy as many hosted cache servers as are needed at a
So the simple overview of deploying BranchCache hosted cache
mode 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 BranchCache
feature 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. No
limitations on the number of hosted cache servers per branch, and no
requirement to design and deploy a public key infrastructure with certificates.
For more information about additional great new features in
BranchCache, you might want to take a look at the topic What's New in
BranchCache, at http://technet.microsoft.com/en-us/library/jj127252.