A company has a headquarters site and a remote site. Cisco Unified Communications Manager acts as a DHCP server. Both sites use their local voice gateways for PSTN calls. At the headquarters site, the PSTN prefix is 9, and the emergency number is 911. At the remote site, the PSTN prefix is 0, and the emergency number is 112. Here are the deployment policies for roaming devices:
. Softphones can roam between two sites.
. A roaming softphone uses the local gateway for all PSTN calls.
. The user keeps home dial habits on a roaming softphone, with the exception of the emergency number.
When a headquarters user uses a softphone at the remote site, prefix 9 can be used to make PSTN calls via voice gateway in the remote site, but emergency number 112 does not work. Which setting on CUCM should be checked?
A. DHCP Subnet
B. Device Mobility Info
C. Physical Location
D. Device Mobility Group
You assign the device pool to the phone device in the Phone Configuration window; you assign device pools to subnets in the Device Mobility Info Configuration window.
Going with C.
https://community.cisco.com/t5/collaboration-voice-and-video/device-mobility/ta-p/3124062
•You can assign one or more device pools to a subnet address. Cisco Unified Communications Manager assigns device pools for the same subnet to roaming devices in round-robin fashion; for example, roaming device 1 gets assigned the first device pool in the list, and roaming device 2 gets assigned the second device pool in the list. This process allows you to load share when you expect a large number of phones to roam into an area, such as a meeting in the head office that employees from all branch locations will attend.
•Although physical location does not represent a required setting in the Device Pool Configuration window, you must define a physical location for a device pool to use the device mobility feature. Be sure to configure physical location for the home location device pool and for the roaming device pool.