Microsoft introduced a new terminology in Windows7 and Windows Server 2008 R2 called BranchCache to reduce traffic load on wide area network called BranchCache. Network enabled with BranchCache cache data in branch and subsequent request to same data is served by cached stored in WAN branch. BranchCache optimizes traffic flow between Windows Server 2008 R2 servers and BranchCache-enabled clients; Windows Server 2008 R2 servers and computers running Windows 7 can be configured as BranchCache clients.
BranchCache operates in one of two modes:
1. Distributed Cache: In Distributed Cache mode, BranchCache-enabled clients cache copies of files downloaded from content servers across the WAN and send them directly to other clients when requested. Distributed Cache mode is especially beneficial for branch offices that do not have a local server.
2. Hosted Cache: In Hosted Cache mode, a Windows Server 2008 R2 server, known as the Hosted Cache, acts as the host for the cached content. BranchCache-enabled clients cache data that they have requested and downloaded from content servers locally and use the Hosted Cache to retrieve data that is not available from their own local cache. Clients know the identity of the Hosted Cache and retrieve data from the Hosted Cache. For data not available from the Hosted Cache, the client downloads the data from the content server and offers it for caching to the Hosted Cache. Hosted Cache mode is beneficial in organizations that want to audit access to content in the local cache, or larger branch offices that have local servers.
BranchCache Hosted and Distributed cache modes
BranchCache improves the performance of applications that use one of the following protocols:
a.Hypertext Transfer Protocol (HTTP) and Hypertext Transfer Protocol Secure (HTTPS). The protocols that Web browsers and many other applications (such as Microsoft Internet Explorer®, Microsoft Windows Media Player®, and more) use.
b.Server Message Block (SMB), including signed SMB traffic. SMB is the protocol used for shared folders on Windows networks.
c.Background Intelligent Transfer Service (BITS). BITS is used to transfer files asynchronously between a client and a server. BITS is the protocol that System Center Configuration manager (SCCM) and Windows Server Update Services (WSUS) use.