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
MESSAGES

Name

Code

User-Authorization-Request 300
User-Authorization-Answer 300
Server-Assignment-Request 301
Server-Assignment-Answer 301
Location-Info-Request 302
Location-Info-Answer 302
Multimedia-Auth-Request 303
Multimedia-Auth-Answer 303
Registration-Termination-Request_Cx 304
Registration-Termination-Answer 304
Push-Profile-Request_Cx 305
Push-Profile-Answer_Cx 305