ABSTRACT
The IMS Control Plane1 is where the necessary message exchange takes place for the registration of a user onto the IMS network and for the establishment of a session. In a pre-IMS network, the establishment of a session would be synonymous with the establishment of a call (or call connection). With IMS, as all services involve Internet Protocol (IP)-based data (including traditional voice calls, e.g., VoIP), a user establishes a data session (or more simply a session) in order to invoke any kind of IMS service.
