3GPP Cx  Application ( 16777216 )

The Cx reference point is located between the Call Session Control Function (CSCF) and the Home Subscriber Server ( HSS). The Cx interface provides user registration status query, authentication, CSCF registration/de-registration notification, network-initiated de-registration, user location query, and updates of user profiles.

Reference:  3GPP TS29.228/TS29.229   View