Section: 4.23.5.1 PDU Session establishment procedure
Content: For non roaming or LBO roaming, it includes the following cases: - If the service area of the selected SMF includes the current UE location, the UE requested PDU Session Establishment procedure is same as described in clause 4.3.2.2.1. - If the service area of the selected SMF does not include the current UE location and the UE does not request for a MA PDU Session, the AMF selects an I-SMF that serves the area where UE camps. The UE requested PDU Session Establishment procedure for Home-routed Roaming defined in clause 4.3.2.2.2 is used to establish the PDU Session. Compared to the procedure defined in clause 4.3.2.2.2, the V-SMF and V-UPF are replaced by I-SMF and I-UPF and H-SMF and H-UPF are replaced by SMF and UPF(PSA) respectively. Also, only the S-NSSAI with the value defined by the serving PLMN is sent to the SMF. The I-SMF provides the DNAI list it supports to SMF and the SMF provides the DNAI(s) of interest for this PDU Session to I-SMF based on the DNAI list information received from I-SMF as defined in Figure 4.23.9.1-1 step 1. This may happen e.g. at PDU Session mobility from non-3GPP access to 3GPP access as defined in clause 4.23.15. - If the service area of the selected SMF does not include the current UE location and the UE requests a MA PDU Session, then the AMF rejects the MA PDU Session Establishment procedure. - When the delegated discovery is used, the SCP selects the SMF as described in Annex E. - If an I-SMF is selected and the PDU Session supports mechanisms for redundant transmission defined in clause 5.33.2.2 of TS 23.501[ System architecture for the 5G System (5GS) ]  [2], the SMF rejects the PDU Session Establishment Request. - If an I-SMF is selected and the PDU Session supports Time Sensitive Communications (as defined in clauses 5.27 and 5.28 of TS 23.501[ System architecture for the 5G System (5GS) ]  [2]), or if the PDU session supports redundant transmission defined in clauses 5.33.2.1 or 5.33.2.3 of TS 23.501[ System architecture for the 5G System (5GS) ]  [2], the SMF may, based on local policy, reject the PDU Session Establishment Request. - If the selected SMF cannot serve the target DNAI requested by the PCC rule, the SMF issues Nsmf_PDUSession_SMContextStatusNotify to provide the target DNAI information to the AMF. The procedure of Home-routed Roaming defined in clause 4.3.2.2.2 is used to establish the PDU Session. Compared to this procedure, the V-SMF and V-UPF are replaced by I-SMF and I-UPF respectively and H-SMF and H-UPF are replaced by SMF and UPF(PSA) respectively. The AMF selects an I-SMF that serves this target DNAI in step 2. Then AMF sends a Nsmf_PDUSession_CreateSMContext Request to the I-SMF as defined in step 3a and the target DNAI received from SMF is included in the message. - The S-NSSAI registered to UDM by SMF is always the S-NSSAI of HPLMN. For the Home-Routed roaming case, the UE requested PDU Session Establishment procedure for Home-routed Roaming in clause 4.3.2.2.2 can be reused with the following change. - If the service area of the selected V-SMF does not include the current UE location and the UE requests a MA PDU Session, then the AMF rejects the MA PDU Session Establishment procedure.