R.3 Session Establishment/Modification at Mobile Origination – Location Info in Response

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

Figure R.3-1: Mobile origination (user location and/or UE Time Zone information included within Response Confirmation)

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

2a. Optionally, the P-CSCF may start procedures to obtain the user location and/or UE Time Zone information from the access network at reception of SDP Offer in parallel with steps 2b to 7.

2b. The P-CSCF sends the INVITE towards the next hop.

3. If an AS is to be invoked for this session the S-CSCF (or I-CSCF) sends the INVITE towards the AS.

4. The AS sends the INVITE towards the S-CSCF.

5. The S-CSCF routes the INVITE towards the terminating side.

6a. The P-CSCF receives an SDP answer sent by the terminating side.

6b. If the P-CSCF did not initiate procedures to obtain the user location and/or UE Time Zone information from the access network at step 2a, it will initiate them. This step will be executed together with Authorization of QoS resources.

6c. The P-CSCF forwards the SDP answer to the UE.

7. The UE provides a response confirmation towards the P-CSCF.

8. The P-CSCF inserts the user location and/or UE Time Zone information provided by the access network in the response confirmation, and this is routed towards the terminating side in steps 9 – 11. 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.