B.1 Subscription to Notification of Signalling Path Status at IMS Registration

29.2133GPPPolicy and charging control signalling flows and Quality of Service (QoS) parameter mappingRelease 17TS

This clause covers the optional Subscription to Notifications of IMS Signalling Path Status upon an initial successful IMS Registration procedure.

Figure B.1.1: Subscription to Notification of IMS Signaling Path Status at initial IMS Registration

1-4. The user initiates an initial SIP Registration procedure. The SIP Registration procedure is completed successfully (user has been authenticated and registered within the IMS Core NW).

5. The P-CSCF requests the establishment of a new Diameter Rx session with the intention to subscribe to the status of the IMS Signaling path. The P-CSCF sends a Diameter AAR command to the PCRF.

6. The PCRF performs session binding and identifies corresponding PCC Rules related to IMS Signalling.

7. The PCRF confirms the subscription to IMS Signaling path status and replies with a Diameter AAR command back to the P-CSCF.

8. If the PCRF had not previously subscribed to the required bearer level events from the IP-CAN for the affected PCC/QoS Rules, then the PCRF shall do so now. The PCRF initiates procedures according to figure 4.3.1.1.1.