IMS S1-2e. SIP 183 Session Progress response: from S-CSCF1 to P-CSCF1

Tech-invite 3GPPspace IETFspace

SIP ↠ Examples Grammars Presence ⇾ Main Services Transaction Dialog IMS

TS 24.228 – §7.2.2 – §7.3.2 – §7.4.2

IMS S1 signalling flow - Session Initiation: Mobile origination and termination roaming, with different network operators - IMS S1-2e. SIP 183 Session Progress response: from S-CSCF1 to P-CSCF1

P-CSCF1 authorizes the resources necessary for this session. The approval of QoS commitment either happens at this stage or after 200 OK of INVITE based on operator local policy.