TOPIC about_BITS_CmdletsSHORT DESCRIPTION Provides background information about the Background Intelligent Transfer Service (BITS). LONG DESCRIPTION This topic provides information about BITS, BITS transfer types, BITS transfer persistence, BITS transfer priority, the Windows PowerShell and BITS cmdlets, and BITS server configuration. This topic also provides links to more information about BITS. About BITS BITS is a file transfer service that provides a scriptable interface through Windows PowerShell. BITS transfers files asynchronously in the foreground or in the background. And, it automatically resumes file transfers after network disconnections and after a computer is restarted. Background transfers use only idle network bandwidth in an effort to preserve the users interactive experience with other network applications such as Internet Explorer. BITS does this by examining the network traffic and then using only the idle portion of the network bandwidth. BITS continuously throttles its use of the bandwidth as the user increases or decreases their use of the bandwidth. BITS performs the transfers asynchronously, which means that your program or script does not have to be running for BITS to perform the transfer. Both uploads and downloads are supported. BITS is particularly suitable for copying files from an HTTP location in an Internet Information Services virtual directory to the logical drive of a client. Standard server message block (SMB) copy operations are also supported. In addition to the scripting interface provided by Windows PowerShell, BITS provides a set of COM APIs to allow programming access. BITS Transfer Types There are three types of BITS transfer jobs: - A download job downloads files to the client computer. - An upload job uploads a file to the server. - An upload-reply job uploads a file to the server and receives a reply file from the server application. BITS Transfer Persistence BITS continues to transfer files after an application exits if the user who initiated the transfer remains logged on and if a network connection is maintained. BITS suspends the transfer if a connection is lost or if the user logs off. BITS also persists the transfer information when a user logs off, when network disconnections occur, and when a computer is restarted. When the user logs on again, when the network is reconnected, and when the computer is restarted, BITS resumes the user's transfer job. BITS Transfer Priority BITS provides one foreground and three background priority levels that you can use to prioritize transfer jobs. Higher priority jobs preempt lower priority jobs. Jobs at the same priority level share transfer time, which prevents a large job from blocking small jobs in the transfer queue. Lower priority jobs do not receive transfer time until all the higher priority jobs are complete or in an error state. Background transfers are optimal because BITS uses idle network bandwidth to transfer the files. BITS increases or decreases the rate at which files are transferred based on the amount of idle network bandwidth that is available. If a network application begins to consume more bandwidth, BITS decreases its transfer rate to preserve the user's interactive experience. BITS supports multiple foreground jobs and one background transfer job at the same time. Windows PowerShell and the BITS Cmdlets Windows PowerShell implements BITS functionality through the BITS module for Windows PowerShell. The BITS module loads a set of BITS-specific cmdlets. You can use these cmdlets to complete the end-to-end tasks that are necessary to manage the transfer of files between computers. When the BITS module for Windows PowerShell is loaded, the following BITS cmdlets are available. Cmdlet Descriptions --------- -------------------------------- Add-BitsFile Adds one or more files to a BITS transfer. Complete-BitsTransfer Completes a BITS transfer. Get-BitsTransfer Gets a single or multiple BITS transfer. Remove-BitsTransfer Deletes a BITS transfer. Resume-BitsTransfer Resumes a suspended BITS transfer. Set-BitsTransfer Configures BITS transfer jobs. Start-BitsTransfer Creates and starts a BITS transfer job. Suspend-BitsTransfer Suspends a BITS transfer job. To copy a file using BITS: 1. Create a BITS transfer job by using the Start-BitsTranfer cmdlet, optionally with the Suspend parameter. 2. Add files to the BITS transfer job by using the Add-BitsFile cmdlet. 3. Start the BITS transfer by using the Resume-BitsTransfer cmdlet. 4. Check the status of the BITS transfer job by using the Get-BitsTransfer cmdlet. Sample Commands A simple Windows PowerShell BITS file transfer command might resemble the following command: C:\PS> Start-BitsTransfer http://server01/servertestdir/testfile1.txt c:\clienttestdir\testfile1.txt A slightly more complex Windows PowerShell BITS file transfer set of commands might resemble the following command: C:\PS> Import-CSV filelist.txt | Start-BitsTransfer -TransferType Upload BITS Server Configuration Background Intelligent Transfer Services (BITS) server extends Internet Information Services (IIS) to support throttled uploads that can be restarted. To upload files to a server by using BITS, the server must be running IIS 7.0 and Windows Server 2008. Additionally, the BITS server extension for the Internet Server Application Programming Interface (ISAPI) must be installed. The BITS server extension is a subcomponent of IIS. To use the upload feature, create an IIS virtual directory on the server where clients can upload files. Create a virtual directory for each type of client. BITS adds properties to the IIS metabase for the virtual directory that you create, and it uses these properties to determine how to upload the files. For more information, see "Setting Up the Server for Uploads" in the MSDN library at http://go.microsoft.com/fwlink/?LinkId=142215. More Information about BITS For more information about BITS, see the following topics in the MSDN (Microsoft Developer Network) library: - "Background Intelligent Transfer Service" http://go.microsoft.com/fwlink/?LinkId=142216 - "About BITS" http://go.microsoft.com/fwlink/?LinkId=142217 SEE ALSO Online version: http://go.microsoft.com/fwlink/?LinkId=142218 Add-BitsFile Complete-BitsTransfer Get-BitsTransfer Remove-BitsTransfer Resume-BitsTransfer Set-BitsTransfer Start-BitsTransfer Suspend-BitsTransfer