Call Control and Mobility Services
Domain 2 - Call Control and Mobility Services
This domain (25%) covers the features that let a user keep the same experience on any phone and any device: Device Mobility, Extension Mobility, Unified Mobility, and the shared-line services (hunt groups, call park, pickup, forwarding).
Device Mobility
Device Mobility Info maps a subnet to a Physical Location and a Device Mobility Group. A phone whose Device Mobility Mode is On is roaming when the group of the subnet it registers from differs from its home group; CUCM then applies the visited location's device-pool settings - region, location bandwidth, SRST reference, MRGL, AAR group, date/time group - so calls and emergency dialing leave through the local gateway.
Extension Mobility and Unified Mobility
Extension Mobility (EM) lets a user log into any EM-subscribed phone and pull in a device profile holding lines, speed dials and CSS. It needs the Cisco Extension Mobility service activated, the phone subscribed to the EM service, a device profile per user, and the user's PIN. Unified Mobility (Mobile Connect) rings a desk phone and remote destinations together: the Remote Destination Profile plus Remote Destinations carry the delay-before-ringing and answer-too-soon timers, and calls are pulled back through the Reroute CSS. Mobile Voice Access lets a mobile user dial into CUCM and place calls using a PIN.
Hunt, park and pickup
A line group holds agents with a distribution algorithm (top-down, circular, longest idle, broadcast). Hunt lists order line groups; the hunt pilot is the dialed number and carries its own forwarding and no-answer handling. Call park uses a park number range in a partition plus a reversion timer; the parking phone monitors the parked call. Call pickup works through the phone's pickup group (group pickup) or a directed pickup of a ringing directory number.
Worked example
Maria normally works in Dallas; her subnet 10.1.5.0/24 maps to DMG-DFW. She travels to Denver and her phone registers from 10.2.7.0/24, mapped to DMG-DEN. Because the groups differ and Device Mobility Mode is On, CUCM marks the phone roaming and applies the Denver device pool: Denver region, Denver location bandwidth, SRST-DEN, MRGL-DEN. Her 911 call now exits the Denver gateway - the operational reason Device Mobility exists.
Traps that cost marks
- Device Mobility Mode left at Off, or the visited subnet missing from Device Mobility Info - the phone silently keeps its home settings.
- An EM device profile without the required line CSS: the user logs in but cannot dial long distance.
- Hunt pilot forwarding ignored because only line-level call forwarding was configured.
- Remote destinations that never ring because the delay-before-ringing or answer-too-soon timers are misconfigured.