5.5 Procedures at the MGCF

5.6 Procedures at the BGCF

5.4.5 Call release

5.4.4 Call initiation

5.4.7 Void

5.4.6 Call-related requests

5.4.3 General treatment for all dialogs and standalone transactions excluding requests terminated by the S-CSCF

5.4.2 Subscription and notification

5.4.1 Registration and authentication

5.2 Procedures at the P-CSCF