When a phone registers with Cisco Unified Communications Manager, some Device Mobility-related configuration settings are checked to determine if and how Device Mobility should be applied to the phone.
Step 1: A device attempts to register with Cisco Unified Communications Manager.
Step 2: Cisco Unified Communications Manager checks if Device Mobility is enabled for the device.
If Device Mobility is not enabled for the device, the default behavior applies (go to Step 10); otherwise continue.
Step 3: Cisco Unified Communications Manager checks if the IP address of the IP phone matches one of the device mobility info’s (IP subnets).
If the IP address does not match any device mobility info, the phone is considered to be in its home location and the default behavior applies (go to Step 10). Otherwise, continue with the next step.
Step 4: The device pool to be used is chosen.
If the home device pool is associated with the device mobility info in which the IP address of the phone was found, the home device pool is chosen.
If the home device pool is not associated with the device mobility info in which the IP address of the phone was found, the device pool is chosen. If more than one device pool is associated with the device mobility info, then the device pool is chosen based on a load-sharing algorithm.
Step 5: If the chosen device pool is the home device pool, the phone is considered to be in its home location and the default behavior applies (go to Step 10). Otherwise, continue with the next step.
Step 6: If the physical locations of the chosen device pool and the home device pool are the same, the phone is considered to be at the same physical location as its home location. The default behavior applies (go to Step 10). Otherwise, the phone is considered to be roaming (continue with the next step).
Step 7: The roaming-sensitive settings of the chosen device pool (the roaming device pool in this case) are used to update the configuration of the phone.
Step 8: Only if the device mobility groups of the chosen device pool and the home device pool are the same, the phone configuration is also updated by applying the Device Mobility-related settings.
Step 9: After the phone configuration has been updated (either with the roaming-sensitive settings only or with the roaming-sensitive settings and the Device Mobility-related settings), the phone is reset so that the updated configuration is applied to the phone.
Step 10: Here is a description of the default behavior. First, the settings of the home device pool (that is, the device pool that is configured at the phone) are applied. Some of the device pool configuration parameters can also be set individually at the phone. These overlapping phone-configuration parameters include the MRGL, Location, Network Locale, Device Mobility CSS (which is simply called the CSS at the phone), AAR CSS, and AAR Group. If these parameters are configured at the phone (that is, are not set to [None]), the phone-configuration settings have priority over the corresponding setting at the device pool.
In summary, the roaming-sensitive parameters are applied when the physical location of the current device pool is different from the physical location of the home device pool (that is, when roaming between physical locations). The Device Mobility-related settings are applied in addition to the roaming-sensitive parameters when the physical locations are different and the device mobility groups are the same (that is, when roaming between physical locations within the same device mobility group).
