[Conditional] AMF to SMF: Nsmf_PDUSession_UpdateSMContext Request (PDU Session ID(s), Cause(s), UE location information, Access Type).
The Nsmf_PDUSession_UpdateSMContext Request is invoked:
If the UE identifies PDU Session(s) to be activated in the NAS Service Request message;
This procedure is triggered by the SMF but the PDU Session(s) identified by the UE correlates to other PDU Session ID(s) than the one triggering the procedure; or
This procedure is triggered by the SMF but the current UE location is outside the "Area of validity for the N2 information" provided by the SMF in step 3a of clause 126.96.36.199. In this case the AMF shall not send the N2 information provided by the SMF in step 3a of clause 188.8.131.52.
The AMF determines the PDU Session(s) to be activated and sends an Nsmf_PDUSession_UpdateSMContext Request to SMF(s) associated with the PDU Session(s) with Cause set to indicate "establishment of user plane resources" for the PDU Session(s).
If the procedure was triggered in response to paging indicating non-3GPP access, and the PDU Session for which the UE was paged is not in the List Of Allowed PDU Sessions provided by the UE, the AMF notifies the SMF that the User Plane for the PDU Session cannot be re-activated. For other PDU Sessions in the List Of Allowed PDU Sessions the Service Request Procedure succeeds without re-activating the User Plane of any PDU Sessions, and the AMF notifies the UE.
The AMF may receive a Service Request to establish another NAS signalling connection via a NG-RAN while it has maintained an old NAS signalling connection for UE still via NG-RAN. In this case, AMF shall trigger the AN release procedure toward the old NG-RAN to release the old NAS signalling connection as defined in clause 4.2.6 with following logic:
For the PDU Sessions indicated in the "PDU Sessions to be activated", the AMF requests the SMF to activate the PDU Session(s) immediately by performing this step 4.
For the PDU Sessions indicated in the "List of PDU Session ID(s) with active N3 user plane" but not in the "PDU Sessions to be activated", the AMF requests the SMF to deactivate the PDU Session(s).