Section: 4.23.5.3 PDU Session modification procedure
Content: For the non-roaming or LBO roaming case, the procedure defined in clause 4.3.3.3 (UE or network requested PDU Session Modification for Home-routed Roaming) is used to modify the PDU Session, with 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. If the QoS Monitoring as defined in clause 5.33.3 of TS 23.501[ System architecture for the 5G System (5GS) ]  [2] is triggered, the following enhancement to clause 4.3.3.3 applies: - In step 3, if the SMF determines the need for QoS Monitoring for a QoS flow according to the information received from the PCF in step 1b, or based on SMF local policy, SMF includes QoS Monitoring indication and how frequently QoS Monitoring reporting to be performed, in Nsmf_PDUSession_Update Request message. - In step 3, if, according to the information received from the PCF in step 1b, or based on SMF local policy, the SMF determines the need for GTP-U Path Monitoring as defined in clause 5.33.3.3 of TS 23.501[ System architecture for the 5G System (5GS) ]  [2], the SMF includes QoS monitoring policy in Nsmf_PDUSession_Update Request message. - In step 4b, if in step 3 the I-SMF received QoS Monitoring indication and may receive how frequently QoS Monitoring reporting to be performed in Nsmf_PDUSession_Update Request the I-SMF includes the QoS Monitoring indication and how frequently QoS Monitoring reporting to be performed in N2 SM message sent to the 5G AN. - In step 4b, if in step 3 the I-SMF received QoS monitoring policy indication and may receive how frequently QoS Monitoring reporting to be performed in Nsmf_PDUSession_Update Request, the I-SMF includes such QoS monitoring policy also to I-UPF for GTP-U path monitoring. - In step 15, the I-SMF sends Nsmf_PDUSession_Update Response to SMF. The SMF updates N4 session of the UPF PSA as defined for the case where is no I-SMF. - If later on the RAN provides over N2 the QoS Monitoring Result with UL packet delay information comprising the packet delays of RAN and N3 interface, the I-SMF forwards this information to the SMF in Nsmf_PDUSession_Update Request message. - I-SMF shall forward monitoring report (for QoS monitoring per GTP-U path) from I-UPF to SMF.