Extension Mobility
                              		in Cisco Unified CME 4.2 and later versions provides the benefit of phone
                              		mobility for end users. 
                              	 
                           
                           A user login service
                              		allows phone users to temporarily access a physical phone other than their own
                              		phone and utilize their personal settings, such as directory number, speed-dial
                              		lists, and services, as if the phone is their own desk phone. The phone user
                              		can make and receive calls on that phone using the same personal directory
                              		number as is on their own desk phone. 
                              	 
                           
                           Each
                              		Cisco Unified IP phone that is enabled for Extension Mobility is configured
                              		with a logout profile. This profile determines the default appearance of a
                              		phone that is enabled for Extension Mobility when there is no phone user logged
                              		into that phone. Minimally, the logout profile allows calls to emergency
                              		services such as 911. A single logout profile can be applied to multiple
                              		phones. 
                              	 
                           
                           After a
                              		Cisco Unified IP phone that is enabled for Extension Mobility boots up, the
                              		Services feature button on the phone is configured with a login service URL
                              		hosted by Cisco Unified CME that points to the Extension Mobility Login page.
                              		No feature-button-specifc configuration is required to add Extension Assigner
                              		to the Services feature button. The option for Extension Mobility appears last
                              		in the list of options displayed when the phone user presses the Services
                              		feature button 
                              	 
                           
                           A phone user logs in
                              		to a Cisco Unified IP phone that is enabled for Extension Mobility by pressing
                              		the Services button or a Unified CCX agent can log in using a Unified CCX Cisco
                              		Agent Desktop. User authentication and authorization is performed by Cisco
                              		Unified CME. If the login is successful, Cisco Unified CME retrieves the
                              		appropriate user profile, based on user name and password match, and replaces
                              		the phone’s logout profile with the user profile. 
                              	 
                           
                           After the phone user
                              		is logged in, the service URL points to a logout URL hosted by
                              		Cisco Unified CME to provide a logout prompt on the phone. Logging into a
                              		different device automatically closes the first session and start a new session
                              		on the new device. When a phone user is not logged in to any phone, incoming
                              		calls to the phone user’s directory number are sent to the phone user’s voice
                              		mailbox. 
                              	 
                           
                           For button
                              		appearance, Extension Mobility associates directory numbers then speed-dial
                              		numbers in the logout profile or user profile to phone buttons. The sequence in
                              		which directory numbers are associated is based on line type and ring behavior
                              		as follows: first normal, then silent ring, beep ring, feature ring, monitor
                              		ring, and overlay, followed by speed dials. If the profile contains more
                              		numbers than there are buttons on the physical phone to which the profile is
                              		downloaded, the remaining numbers in the profile are ignored. 
                              	 
                           
                           For configuration
                              		information, see 
                              		Enable Extension Mobility.