R.2 Session Establishment/Modification at Mobile Origination – Location Info in Request

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

This information flow shows the procedure when operator policy requires the the user location and/or UE Time Zone information to be included within IMS session establishment/modification signalling before sending the INVITE towards the terminating side.

Figure R.2 -1: Mobile origination (user location and/or UE Time Zone information included within INVITE)

1. The UE sends a SIP INVITE request. It can contain user location information provided by the UE.

2. The P-CSCF obtains the user location and/or UE Time Zone information from the access network.

3. The P-CSCF includes the user location and/or UE Time Zone information obtained from the access network and sends the INVITE towards the next hop together with the user location information provided by the UE.

4. If an AS is to be invoked for this session, the S-CSCF (or I-CSCF) sends the INVITE towards the AS, including the user location and/or UE Time Zone information (assuming the AS is in the same trust domain).

5. The AS sends the INVITE towards the S-CSCF, still containing the user location and/or UE Time Zone information.

6. The S-CSCF routes the INVITE towards the terminating side. 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) before routing outside the trust domain.