About Client Roaming in Configuration Manager
Applies To: System Center Configuration Manager 2007, System Center Configuration Manager 2007 R2, System Center Configuration Manager 2007 R3, System Center Configuration Manager 2007 SP1, System Center Configuration Manager 2007 SP2
Roaming in Configuration Manager 2007 refers to the ability of clients to move between sites in the Configuration Manager hierarchy and continue to be managed while making the best use of network resources.
When the client is no longer within the designated boundaries of its assigned site, roaming behavior allows Configuration Manager 2007 clients to find the closest distribution points from which to download package source files required for software distribution, software updates, or operating system deployment. These package source files are collectively known as content.
Roaming behavior helps reduce the need for clients to download content over slow or unreliable network connections so that clients receive the content they need as efficiently as possible, and network bandwidth usage is minimized.
Roaming is ideally suited to laptop computers that move from one location on the network, to another. Some examples of client roaming are the following:
Moving a laptop computer from building to building.
Moving a laptop computer from one geographical location to another.
Moving a laptop computer from its wired network connection and connecting to the network using a wireless network card.
Removing a laptop computer from the office and connecting it to a virtual private network (VPN) from home.
Configuration Manager 2007 boundaries are used to identify a roaming client's position in the Configuration Manager 2007 hierarchy, which in turn facilitates locating the nearest distribution points that host the content requested by clients.
When a change in network location results in a client being outside its assigned site's boundaries, it relies on roaming behavior to locate content.
For more information about planning Configuration Manager 2007 site boundaries, see Planning Configuration Manager Boundaries, and for more information about content location, see Configuration Manager and Content Location (Package Source Files).
Roaming Capabilities: Global and Regional
When a client has global roaming capability, the Configuration Manager 2007 client can access site information from Active Directory Domain Services. This requires that the Active Directory schema is extended for Configuration Manager 2007, all sites are publishing to Active Directory Domain Services, and the client belongs to the same forest. This is not possible for clients from another forest, workgroup clients, or mobile devices.
For more information about extending the Active Directory schema to enable global roaming capability, see How to Extend the Active Directory Schema for Configuration Manager.
When a client does not have global roaming capability because it cannot access site information from Active Directory Domain Services, it has regional roaming capability. This offers more limited roaming support in that a client can download content locally from sites lower than its assigned site in the Configuration Manager 2007 hierarchy, but it cannot download content locally from sibling sites, or sites higher in the hierarchy.
Global Roaming Behavior
A client that has global roaming capability first identifies the site into which it has roamed by comparing its current IP address with the list of IP networks that define the boundaries in the Configuration Manager 2007 hierarchy.
When the client finds a match for the boundary, it can then identify which site is configured for that boundary, and then locate the management point for that site. This default management point for the site that the client has roamed into is referred to as the resident management point.
The resident management point informs the roaming client of distribution points in its site that contain package source files the client can access. However, if the package source files are not available in the site the client has roamed into, the client falls back to asking its default management point for distribution points.
Regional Roaming Behavior
When clients cannot access Configuration Manager 2007 site information published to Active Directory Domain Services, clients continue to contact the default management point in their assigned site. They are not aware of the site's identity that they have roamed into, or of management points in that site.
In this scenario, when clients roam into a site that is lower in the hierarchy than their assigned site (for example, a child site or a grandchild site), the client's default management point informs the roaming client of the closest distribution points the client can access.
How Roaming Clients Locate Content
When a roaming client needs to access content such as an advertised program's package source files, it sends a content location request to the resident management point if it has global roaming capability, or to its default management point if it has regional roaming capability.
The management point determines which distribution points contain the content requested and are available to the client. It makes this determination by checking whether the distribution points are in a fast or slow network boundary associated with the boundary the client computer is in, and if the client is located within the boundaries of a protected distribution point.
For more information about content location, see Configuration Manager and Content Location (Package Source Files).
When Content is Locally Available to Roaming Clients
If content is available from distribution points in the site the client has roamed into, the client downloads the content from these local distribution points.
If the client disconnects before the content has completed its download, and roams into another site or returns to its assigned site, a content download using BITS (download and then run) will continue where it left off even though it is from a different distribution point.
When Content is Not Locally Available to Roaming Clients
If the content isn't available locally in the site the client has roamed into, the advertisement or software update deployment configuration settings determine if the roaming client can access it from distribution points in its assigned site. In some situations, this is advantageous so that the client has the content it needs. In other cases, however, content downloads over slow and unreliable networks usually mean bandwidth saturation and delays if the source files are transferred over WAN links. It can also be an expensive solution for some organizations.
If the advertisement or software update deployment is configured to prevent installation when a client is connected using a slow or unreliable network connection, and the client is currently located on a slow or unreliable site boundary, the client cannot access the package source files.
To prevent clients from accessing package source files across slow or unreliable network links, configure the following settings:
For an advertisement: When a client is connected within a slow or unreliable network boundary: Do not run program on the Advertisement Name Properties: Distribution Points Tab.
For a software update deployment: When a client is connected within a slow or unreliable network boundary: Do not install software updates on the Deployment Name Properties: Download Settings Tab and When no distribution point is available locally: Do not run update installation on the Deployment Name Properties: SMS 2003 Settings Tab.
In this scenario, the client cannot download the content until it returns to its assigned site or it roams into another site that hosts the content on local distribution points. This configuration protects the network from network saturation associated with large packages such as operating system deployment packages and software updates that contain service packs. This is the default setting for both advertisements and software update deployments.
However, if the advertisement or software update deployment is not configured with this option, the client downloads the content from distribution points, even if the content is not local to them. This ensures that the client gets the content it needs, even if it takes a long time to transfer over a slow network and might consume a high proportion of the limited network bandwidth.
When the Configuration Manager 2007 hierarchy contains some sites in native mode, and some sites in mixed mode, this affects roaming behavior. For more information, see Roaming Between Sites in Different Modes.
For example scenarios of how roaming works in different circumstances, see the following:
Overview of Configuration Manager Client Deployment
About Client Site Assignment in Configuration Manager
Choose Configuration Manager Boundaries
Planning Configuration Manager Boundaries
About Configuration Manager Client Installation Properties
For additional information, see Configuration Manager 2007 Information and Support.
To contact the documentation team, email SMSdocs@microsoft.com.