Updated: January 7, 2009
Applies To: Windows Server 2008 R2
Peer caching is a new feature of BITS 3.0 that allows peer computers (computers within the same subnet of a network that have the peer caching feature enabled) to share files. If peer caching is enabled on a computer, the Automatic Update agent instructs BITS to make downloaded files available to that computer's peers as well.
When the files have been downloaded, BITS caches them. When another peer caching-enabled computer tries to download the same update, BITS on that computer sends a multicast request to all of that computer's peers. If one or more of the peers responds to the request, BITS will download the file from the first computer to respond. If the download from the peer fails or takes too long, BITS continues the download from the server.
The following is a list of the managed entities that are included in this managed entity:
The peer caching cache maintains a copy of the files that the BITS client has downloaded as part of a job that allows peer caching. The peer caching server makes this data available to other computers for which peer caching is enabled.
The BITS peer caching server is the BITS component that responds to requests for content from BITS clients.
The BITS peer caching client listens on the network for peer caching servers that are in the same subnet and domain. When a BITS job allows peer caching, the peer caching client queries the peer servers to determine whether one of the servers holds some or all of the requested content. If so, the BITS client downloads as much of the data as possible from the peer servers and downloads the remainder from the origin server.