Applies to: System Center Configuration Manager (Current Branch)
You use boundary groups in System Center Configuration Manager to logically group related network locations (boundaries) to make it easier to manage your infrastructure. Boundaries must be assigned to boundary groups before you can use the boundary group.
By default, Configuration Manager creates a default site boundary group at each site.
The information in this Boundary groups section and its child sections applies to version 1610 or later. This content has been revised to be specific to the design changes introduced for boundary groups with this update version.
If you use versions prior to 1610, see Boundary groups for System Center Configuration Manager versions 1511, 1602, and 1606 for information on how to use and configure boundary groups with those product versions.
To configure boundary groups, you associate boundaries (network locations) and site system roles, like distribution points, to the boundary group. This helps associate clients to site system servers like distribution points that are located near the clients on the network.
When you assign the same boundary to multiple boundary groups, and assign the same site system servers, like distribution points, to multiple boundary groups you increase the availability of site systems to a wider range of network locations.
Clients use a boundary group for:
- Automatic site assignment
- To find a site system server that can provide a service, including:
- Distribution points for content location
- Software update points (beginning with version 1702)
- State migration points
- Preferred management points (If you use preferred management points, you must enable this option for the hierarchy and not from within the boundary group configuration. See To enable use of preferred management points in this topic.)
Boundary groups and relationships
For each boundary group in your hierarchy, you can assign:
- One or more boundaries. When a client is on a network location that is defined as a boundary assigned to a specific boundary group, that is called the current boundary group. A client can have more than one current boundary group.
- One or more site system roles. Clients can always use site system roles associated with their current boundary group. Depending on additional configurations, they might be able to use site system roles in additional boundary groups.
For each boundary group you create, you can configure a one-way link to another boundary group. The link is called a relationship. The boundary groups you link to are called neighbor boundary groups. A boundary group can have multiple relationships, each with a specific neighbor boundary group.
The configuration of each relationship determines when a client that fails to find an available site system server in its current boundary group can begin to search a neighbor boundary group to find an available site system. This search of additional groups is called fallback.
To prevent problems for clients when they cannot find an available site system in their current boundary group, you define relationship between boundary groups that defines fallback behavior. Fallback lets a client expand its search to additional boundary groups to find an available site system.
Relationships are configured on a boundary group properties Relationships tab. When you configure a relationship, you define a link to a neighbor boundary group. For each type of site system role that is supported, you can configure independent settings for fallback to that neighbor boundary group. As an example, when you configure a relationship to a specific boundary group you can set fallback for distribution points to occur after 20 minutes instead of the default of 120. See Example of using boundary groups for a more extensive example.
If a client fails to find an available site system role in its current boundary group, the client uses the fallback time in minutes to determine after how long it can begin to search for an available site system that is associated with that neighbor boundary group.
When a client can’t find an available site system and begins to search locations from neighbor boundary groups, it increases the pool of available site systems that it can use in a manner that is defined by your configuration of boundary groups and their relationships.
- A boundary group can have more than one relationship. With mulitple relationships you can configure fallback for each type of site system to different neighbors to occur after different periods of time.
- Clients only fallback to a boundary group that is a direct neighbor of their current boundary group.
- When a client is a member of multiple boundary groups, the current boundary group is defined as a union of all that client’s boundary groups. That client can then fallback to neighbors of any of those original boundary groups.
The default site boundary group
In addition to the boundary groups you create, each site has a default site boundary group that is created by Configuration Manager. This group is named Default-Site-Boundary-Group<sitecode>. For example, the group for site ABC would be named Default-Site-Boundary-Group<ABC>.
For each boundary group you create, Configuration Manager automatically creates an implied link to each default site boundary group in the hierarchy.
- The implied link is a default fallback option from a current boundary group to the sites default boundary group that has a default fallback time of 120 minutes.
- Clients that are not on a boundary associated with any boundary group in your hierarchy use the default site boundary group from their assigned site to identify valid site system roles they can use.
To manage fallback to the default site boundary group:
- You can go to the site default boundary group’s properties and change the values on the Default Behavior tab. Changes you make here apply to all implied links to this boundary group. These settings can be overridden when you configure the explicit link to this default site boundary group from another boundary group.
- You can go to the properties of a boundary group you created, and change the values for the explicit link that goes to a default site boundary group. When you set a new time in minutes for fallback or block fallback, that change affects only the link you are configuring. Configurations of the explicit link override those on the Default Behavior tab of a default site boundary group.
You can configure each boundary group with an assigned site for clients.
- A newly installed client that uses automatic site assignment joins the assigned site of a boundary group that contains the client's current network location.
- After assigning to a site, a client does not change its site assignment when it changes its network location. For example, if the client roams to a new network location that is represented by a boundary in a boundary group with a different site assignment, the client's assigned site remains unchanged.
- When Active Directory System Discovery discovers a new resource, network information for the discovered resource is evaluated against the boundaries in boundary groups. This process associates the new resource with an assigned site for use by the client push installation method.
- When a boundary is a member of multiple boundary groups that have different assigned sites, clients randomly select one of the sites.
- Changes to a boundary groups assigned site only apply to new site assignment actions. Clients that previously assigned to a site, do not reevaluate their site assignment based on changes to the configuration of a boundary group (or to their own network location).
For more information about client site assignment, see Using Automatic Site Assignment for Computers in How to assign clients to a site in System Center Configuration Manager.
When a client requests the location of a distribution point, Configuration Manager sends the client a list that includes the site systems of the appropriate type that are associated with each boundary group that includes the clients current network location:
During software distribution, clients request a location for deployment content that is available from a distribution point, or other valid content source (like a client configured for Peer Cache).
During operating system deployment, clients request a location to send or receive their state migration information.
During content deployment, if a client requests content that is not available from a source in its current boundary group, the client continues to request that content trying different content sources in its current boundary group until the fallback period for a neighbor boundary group or the default site boundary group is reached. If the client has not yet found content, it then expands its search for content sources to include the neighbor boundary groups.
However, If the content is distributed on-demand and not available on a distribution point when requested by a client, the process to transfer the content to that distribution point begins, and it is possible the client will find that server as a content source before falling back to use a neighbor boundary group.
Software update points
Beginning with version 1702, clients use boundary groups to find a new software update point. You can add individual software update points to different boundary groups to control which servers a client can find.
If you update from a version prior to 1702, all existing software update points are added to the default site boundary group at each site. This maintains the pre-update behavior where clients select a software update point from the pool of available software update points that you have configured for your hierarchy. This behavior is maintained until you choose to add individual software update points to different boundary groups for controlled selection and fallback behavior.
If you install a new site that runs version 1702 or later, software update points are not added to the default site boundary group. Assign software update points to a boundary group so that clients can find and use them.
Fallback for software update points
Fallback for software update points is configured like other site system roles, but has the following caveats:
New clients use boundary groups to select software update points. After you install version 1702, new clients that you install select a software update point from those associated with the boundary groups you have configured. This replaces the previous behavior where clients select a software update point randomly from a list of those that share the client’s forest.
Clients continue to use a last-known good software update point until they fallback to find a new one. Clients that already have a software update point continue to use that software update point until that server cannot be reached. This includes continued use of a software update point that is not associated with the client’s current boundary group.
The continued use of an existing software update point even when that server is not in the client’s current boundary group is intentional. This is because a change of software update point can result in a large use of network bandwidth as the client synchronizes data with the new software update point. The delay in transition can help to avoid saturating your network if all your clients switch to a new software update point at the same time.
A client always attempts to reach its last known-good software update point for 120 minutes before starting fallback. After 120 minutes, if the client has not established contact, it then begins fallback. When fallback starts, the client receives a list of all software update points from its current boundary group. Additional software update points from neighbor boundary groups and site default boundary group are available based on fallback configurations.
Fallback configurations for software update points
Beginning with version 1706
You can configure Fallback times (in minutes) for software update points to be less than 120 minutes. However, the client must still attempt to reach its original software update point for 120 minutes before it expands it search to additional servers. Because boundary group fallback times start when the client first fails to reach its original server, any boundary groups that are configured for less than 120 minutes are provided to the client when it expands its search after failing to reach its original server for 120 minutes.
You can configure Never fallback to block fallback for a software update point to a neighbor boundary group.
After failing to reach its original server for two hours, the client then uses a shorter cycle to establish a connection to a new software update point. This enables the client to rapidly search through the expanding list of potential software update points.
- Example of fallback:
A client’s current boundary group has fallback for software update points that is configured as 10 minutes for boundary group A, and 130 minutes for boundary group B. When the client fails to reach its last known-good software update point:
- The client attempts to reach only its original server for the next 120 minutes. After 10 minutes, the software update points from boundary group A are added to the pool of available servers. However, the client cannot attempt to contact them or any other server until the initial 120-minute period to reconnect with the original server has elapsed.
- After trying to locate that original software update point for 120 minutes, the client can then expand its search. At that time, servers in the client’s current boundary group and any neighbor boundary groups that are configured for 120 minutes or less, are added to the available pool of software update points. This includes the servers in boundary group A which were previously added to the pool of available servers.
- After 10 more minutes (130-minutes total time after the client first failed to reach its last known-good software update point), the client expands the search to include software update points from boundary group B.
Prior to version 1706
Prior to version 1706, fallback configurations for software update points do not support a configurable time in minutes. Instead, fallback behavior is limited to:
- Fallback times (in minutes): This option is grayed out for software update points and cannot be configured. It is set to 120 minutes.
- Never fallback: You can block fallback for a software update point to a neighbor boundary group when you use this configuration.
When a client that already has a software update point fails to reach it, the client can then fallback to find another. When using fallback, the client receives a list of all software update points from its current boundary group. If it fails to find an available server for 120 minutes, it will then fallback to its neighbor boundary groups and the default site boundary group. Fallback to both boundary groups happens at the same time because the software update points fallback time to neighbor groups is set to 120 minutes and cannot be changed. 120 minutes is also the default period used for fallback to the default site boundary group. When a client falls back to both a neighbor and default site boundary group, the client attempts to contact software update points from the neighbor boundary group before trying to use one from the default site boundary group.
Manually switch to a new software update point
In addition to using fallback, you can use Client Notification to manually force a device to switch to a new software update point.
When you switch to a new server, the devices use fallback to find that new server. Therefore, review your boundary group configurations, and ensure that your software update points are in the correct boundary groups before you start this change.
For more information, see Manually switch clients to a new software update point.
Preferred management points
Preferred management points enable a client to identify a management point that is associated with its current network location (boundary).
- A client attempts to use a preferred management point from its assigned site before using a management point from its assigned site that is not configured as preferred.
- To use this option, you must enable it for the hierarchy and then configure boundary groups at individual primary sites to include the management points that should be associated with that boundary group's associated boundaries.
- When preferred management points are configured and a client organizes its list of management points, the client places the preferred management points at the top of its list of assigned management points (which includes all management points from the client's assigned site).
When a client roams (which means to change its network locations such as when a laptop travels to a remote office location) it might use a management point (or proxy management point) from the local site at its new location before attempting to use a management point from its assigned site (which includes the preferred management points). See Understand how clients find site resources and services for System Center Configuration Manager for more information.
Configuration Manager supports overlapping boundary configurations for content location:
- When a client requests content, and the client network location belongs to multiple boundary groups, Configuration Manager sends the client a list of all distribution points that have the content.
- When a client requests a server to send or receive its state migration information, and the client network location belongs to multiple boundary groups, Configuration Manager sends the client a list of all state migration points that are associated with a boundary group that includes the current network location of the client.
This behavior enables the client to select the nearest server from which to transfer the content or state migration information.
Example of using boundary groups
The following example uses a client searching for content from a distribution point. This example can be applied to other site system roles that use boundary groups. However, as applies to software update points, keep in mind that software update points do not support configuration of a time in minutes for fallback to a neighbor group, and always use a period of 120 minutes.
You create three boundary groups that do not share boundaries or site system servers:
- Group BG_A with distribution points DP_A1 and DP_A2 associated to the group
- Group BG_B with distribution points DP_B1 and DP_B2 associated to the group
- Group BG_C with distribution points DP_C1 and DP_C2 associated to the group
You add the network locations of your clients as boundaries to only the BG_A boundary group, and you then configure relationships from that boundary group to the other two boundary groups:
- You configure distribution points for the first neighbor group (BG_B) to be used after 10 minutes. This group contains distribution points DP_B1 and DP_B2. Both are well connected to the first groups boundary locations.
- You configure the second neighbor group (BG_C) to be used after 20 minutes. This group contains distribution points DP_C1 and DP_C2. Both are across a WAN from the other two boundary groups.
You also add an additional distribution point that is located on the site server to the sites default site boundary group. This is your least preferred content source location, but it is centrally located to all your boundary groups.
Example of boundary groups and fallback times:
With this configuration:
- The client begins searching for content from distribution points in its current boundary group (BG_A), searching each distribution point for two minutes before switching to the next distribution point in the boundary group. The clients pool of valid content source locations includes DP_A1 and DP_A2.
- If the client fails to find content from its current boundary group after searching for 10 minutes, it then adds the distribution points from the BG_B boundary group to its search. It then continues to search for content from a distribution point in its combined pool of distribution points that now includes those from both the BG_A and BG_B boundary groups. The client continues to contact each distribution point for two minutes before switching to the next distribution point from its pool. The clients pool of valid content source locations includes DP_A1, DP_A2, DP_B1, and DP_B2.
- After an additional 10 minutes (20 minutes total) if the client still has not found a distribution point with content, it expands its pool of available distribution points to include those from the second neighbor group, boundary group BG_C. The client now has 6 distribution points to search (DP_A1, DP_A2, DP_B2, DP_B2, DP_C1, and DP_C2) and continues changing to a new distribution point every two minutes until content is found.
- If the client has not found content after a total of 120 minutes, it falls back to include the default site boundary group as part of its continued search. Now the pool of distribution points includes all the distribution points from the three configured boundary groups, and the final distribution point located on the site server computer. The client then continues its search for content, changing distribution points every two minutes until content is found.
By configuring the different neighbor groups to be available at different times you control when specific distribution points are added as a content source location, and when, or if, the client uses fallback to the default site boundary group as a safety net for content that is not available from any other location.
Update existing boundary groups to the new model
When you update to version prior to 1610, the following configurations are automatically made. These are intended to ensure your current fallback behavior remains available until you configure new boundary groups and relationships.
- A default site boundary group is created for each primary site, the name is Default-Site-Boundary-Group<sitecode>.
- Distribution points with Allow fallback source location for content checked and state migration points at primary sites are added to the Default-Site-Boundary-Group<sitecode> boundary group of that site.
- Beginning with version 1702, software update points are added to each sites Default-Site-Boundary-Group<sitecode>.
A copy is made of each existing boundary group that includes a site server configured with a slow connection. The name of the new group is <original boundary group name>-<original boundary group ID>:
- Site systems that have a fast connection are left in the original boundary group.
- A copy of site systems (distribution points, management points) that have a slow connection are added to the copy of the boundary group. The original site systems configured as slow remain in their original boundary groups for backward compatibility, but are not used from those boundary groups.
- This boundary group copy does not have boundaries associated with it. However, A fallback link is created between the original group and the new boundary group copy that has the fallback time set to zero.
Specific to secondary sites:
- A boundary group is created if a secondary site has at least one distribution point with Allow fallback source location for content checked or state migration point. The name of the boundary group is Secondary-Site-Neighbor--Tmp<Sitecode>.
- All distribution points with Allow fallback source location for content checked and state migration points are added to this newly created secondary site boundary group.
- A fallback link is created between the original boundary group and the newly created neighbor boundary group and the fallback time is set to zero.
The following table identifies the new fallback behavior you can expect from the combination the original deployment settings and distribution point configurations:
|Original deployment configuration for “Do not run program” in slow network||Original distribution point configuration for “Allow client to use a fallback source location for content”||New fallback behavior|
|Selected||Selected||No fallback - Only use the distribution points in current boundary group|
|Selected||Not selected||No fallback - Only use the distribution points in current boundary group|
|Not selected||Not selected||Fallback to neighbor - Use the distribution points in current boundary group, and then add the distribution points from the neighbor boundary group. Unless an explicit link to the default site boundary group is configured, clients will not fallback to that group.|
|Not selected||Selected||Normal fallback - Use distribution points in current boundary group, then those from the neighbor and site default boundary groups|
All other deployment configurations result in Normal fallback.
Changes from prior versions for UI and behavior for content locations
The following are the key changes to boundary groups and how clients find content. These changes are introduced with version 1610. Many of these changes and concepts work together.
- Configurations for Fast or Slow are removed: You no longer configure individual distribution points to be fast or slow. Instead, each site system associated with a boundary group is treated the same. Because of this change, the References tab of the boundary group properties no longer supports the configuration of Fast or Slow.
New default boundary group at each site: Each primary site has a new default boundary group named Default-Site-Boundary-Group<sitecode>. When a client is not on a network location that is assigned to a boundary group, that client will use the site systems associated with the default group from its assigned site. Plan to use this boundary group as a replacement to the concept of fallback content location.
- ‘Allow fallback source locations for content’ is removed: You no longer explicitly configure a distribution point to be used for fallback, and the options to set this are removed from the UI.
Additionally, the result of setting Allow clients to use a fallback source location for content on a deployment type for applications has changed. This setting on a deployment type now enables a client to use the default site boundary group as a content source location.
- Boundary groups relationships: Each boundary group can be linked to one or more additional boundary groups. These links form relationships that are configured on the new boundary group properties tab named Relationships:
- Each boundary group that a client is directly associated with is called a current boundary group.
- Any boundary group a client can use due to an association between that client’s current boundary group and another group is called a neighbor boundary group.
It is on the Relationships tab that you add boundary groups that can be used as a neighbor boundary group. You can also configure a time in minutes that determines when a client that fails to find content from a distribution point in the current group will begin to search content locations from those neighbor boundary groups.
When you add or change a boundary group configuration, you will have the option to block fallback to that specific boundary group from the current group you are configuring.
To use the new configuration, you define explicit associations (links) from one boundary group to another, and configure all distribution points in that associated group with the same time in minutes. The time you configure determines when a client that fails to find a content source from its current boundary group can begin to search for content sources from that neighbor boundary group.
In addition to boundary groups you explicitly configure, each boundary group has an implied link to the default site boundary group. This link becomes active after 120 minutes at which time the default site boundary group becomes a neighbor boundary group which allows the clients to use the distribution points associated with that boundary group as content source locations.
This behavior replaces what was previously referred to as fallback for content. You can override this default behavior of 120 minutes by explicitly associating the default site boundary group to a current group, and setting a specific time in minutes, or blocking fallback entirely to prevent its use.
Clients attempt to get content from each distribution point for up to 2 minutes: When a client searches for a content source location, it attempts to access each distribution point for 2 minutes before then trying another distribution point. This is a change from previous versions where clients attempted to connect to a distribution point for up to 2 hours.
The first distribution point that a client attempts to use is randomly selected from the pool of available distribution points in the client’s current boundary group (or groups).
After two minutes, if the client has not found the content, it switches to a new distribution point and attempts to get content from that server. This process repeats every two minutes until the client finds the content or reaches the last server in its pool.
If a client cannot find a valid content source location from its current pool before the period for fallback to a neighbor boundary group is reached, the client then adds the distribution points from that neighbor group to the end of its current list and will then search the expanded group of source locations that includes the distribution points from both boundary groups.
When you create an explicit link from the current boundary group to the default site boundary group and define a fallback time that is less than the fallback time for a link to a neighbor boundary group, clients will begin searching source locations from the default site boundary group before including the neighbor group.
When the client fails to get content from the last server in the pool, it begins the process again.
Procedures for boundary groups
The following procedures apply to version 1610 or later. If you use version prior to 1610, see the procedures in Boundary groups for System Center Configuration Manager versions 1511, 1602, and 1606.
To create a boundary group
In the Configuration Manager console, click Administration > Hierarchy Configuration > Boundary Groups.
On the Home tab, in the Create group, click Create Boundary Group.
In the Create Boundary Group dialog box, select the General tab and specify a Name for this boundary group.
Click OK to save the new boundary group.
To configure a boundary group
In the Configuration Manager console, click Administration > Hierarchy Configuration > Boundary Groups.
Select the boundary group you want to modify.
On the Home tab, in the Properties group, click Properties.
In the Properties dialog box for the boundary group, select the General tab to modify the boundaries that are members of this boundary group:
To add boundaries, click Add, select the check box for one or more boundaries, and click OK.
To remove boundaries, select the boundary and click Remove.
Select the References tab to modify the site assignment and associated site system server configuration:
To enable this boundary group for use by clients for site assignment, select the check box for Use this boundary group for site assignment, and then select a site from the Assigned site dropdown box.
To configure which available site system servers are associated with this boundary group:
Click Add, and then select the check box for one or more servers. The servers are added as associated site system servers for this boundary group. Only servers that have supported site system role installed on them are available.
You can select any combination of available site systems from any site in the hierarchy. Selected site systems are listed on the Site Systems tab in the properties of each boundary that is a member of this boundary group.
To remove a server from this boundary group, select the server and then click Remove.
To stop use of this boundary group for associating site systems you must remove all servers listed as associated site system servers.
Select the Relationships tab to configure fallback behavior:
Click Add, and then select the boundary group you want to configure.
Set a fallback time for distribution points. After this period of time, clients in the boundary group you are configuring relationships for, will be able to begin searching for content from the distribution points of the boundary group you are adding.
To prevent fallback to a specific boundary group, including the default site boundary group which is configured by default, select the boundary group and then check the box for Never fallback.
Click OK to close the boundary group properties and save the configuration.
To associate a site systme server with a boundary group
In the Configuration Manager console, click Administration > Hierarchy Configuration > Boundary Groups.
Select the boundary group you want to modify.
On the Home tab, in the Properties group, click Properties.
In the Properties dialog box for the boundary group, select the References tab.
Under Select site system servers, click Add, select the check box for the site system servers you want to associate with this boundary group, and then click OK.
Click OK to close the dialog box and save the boundary group configuration.
To configure a fallback site for automatic site assignment
In the Configuration Manager console, click Administration > Site Configuration > Sites.
On the Home tab, in the Sites group, click Hierarchy Settings.
On the General tab, select the checkbox for Use a fallback site, and then select a site from the Fallback site drop-down list.
Click OK to save the configuration.
To enable use of preferred management points
In the Configuration Manager console, click Administration > Site Configuration > Sites, and then on the Home tab select Hierarchy Settings.
On the General tab of the Hierarchy Settings, select Clients prefer to use management points specified in boundary groups.
Click OK to close the dialog box and save the configuration.