R.6 Session Release

23.2283GPPIP Multimedia Subsystem (IMS)Release 18Stage 2TS

The call flows in this clause present the mobile or network initiated IMS session release for both the Mobile Originating (MO) side and the Mobile Terminating (MT) side valid when either P-CSCF or an IMS AS retrieve user location and/or UE Time Zone information from the access network.

Figure R.6-1: IMS Session Release

Terminating Side:

1. A session release message which terminates the dialog, e.g., BYE, is received by the P-CSCF/IMS AS.

2. The P-CSCF/IMS AS invokes procedures to obtain the user location and/or UE Time Zone information from the access network. In the P-CSCF, this step will be executed together with the procedure to release corresponding QoS resources in the IP-CAN.

3. The P-CSCF/IMS AS forwards the BYE message to the UE or the S-CSCF respectively.

4. The UE/S-CSCF provides a response to the P-CSCF/IMS AS.

5. The P-CSCF/IMS AS inserts the user location and/or UE Time Zone information in the response confirmation, and this is routed towards IMS Core.

Originating Side:

6. A session release message which terminates the dialog, e.g. BYE, is received by the P-CSCF/IMS AS.

7. The P-CSCF/IMS AS invokes procedures to obtain the user location and/or UE Time Zone information from the access network. In the P-CSCF, this step will be executed together with the procedure to release corresponding QoS resources in the IP-CAN.

8. The P-CSCF/IMS AS forwards the BYE message within IMS Core containing the user location and/or UE Time Zone information together with the user location information provided by the UE. The user location and/or UE Time Zone information may be removed or modified (e.g. to change location granularity to just indicate the serving PLMN) if routing outside the trust domain is needed.

9-10. The Session Release procedure is completed.

Annex S (normative):
Business Trunking