<p>IP Multimedia Subsystem Applications A method and apparatus for identifying an IP Multimedia Subsystem (IMS) application in a communications network. A sending device includes an application category identifier identifying a category of the IMS application in a Contact and an Accept- Contact header of a Session Initiation Protocol (SIP) message. An application identifier identifying the IMS application is included in a Session Description Protocol attribute of the Session Initiation Protocol message. The sending device then sends the SIP message towards a receiving device. This reduces the number of identifiers for specific applications that must be handled by the IMS Core.</p>
