[Conditional] SMF to AMF: Nsmf_PDUSession_UpdateSMContext Response (N2 SM information (PDU Session ID, QFI(s), QoS profile(s), CN N3 Tunnel Info, S‑NSSAI), Cause) to the AMF.
For a PDU Session that the SMF has determined to accept the activation of UP connection in step 5, the SMF generates only N2 SM information and sends Nsmf_PDUSession_UpdateSMContext Response to the AMF to establish the User Plane(s). The N2 SM information contains information that the AMF shall provide to the RAN. If the SMF decided to perform PSA UPF relocation for the SSC mode 3 PDU Session, the SMF triggers Relocation of SSC mode 3 PDU Session anchor as described in subclause 188.8.131.52 or subclause 184.108.40.206 after accepting the activation of UP of the PDU Session.
In the following cases, the SMF can reject the activation of UP of the PDU Session by including a cause in the Nsmf_PDUSession_UpdateSMContext Response:
If the PDU Session corresponds to a LADN and the UE is outside the area of availability of the LADN as described in step 5;
If the AMF notified the SMF that the UE is reachable only for regulatory prioritized service, and the PDU Session to be activated is not for a regulatory prioritized service; or
If the SMF decided to change the PSA UPF for the requested PDU Session as described in step 5. In this case, after sending Nsmf_PDUSession_UpdateSMContext Response, the SMF triggers another procedure to instruct UE to re-establish the PDU Session as described in clause 220.127.116.11 for SSC mode 2.