System and method for VoIP call transfer using instant message service in an IP multimedia subsystem

摘要

The Instant Messaging capability of an IP multimedia subsystem is utilized to support call transfer service for VoIP users. A call transfer request from a first VoIP user to a second VoIP user is sent to the IP multimedia subsystem in a predetermined non-standard SIP communication. The IP multimedia subsystem invokes Instant Messaging service in response to the predetermined non-standard SIP communication, and Instant Messaging service is then utilized to support the call transfer dialogue.