A.46 Monitoring of round-trip GTP packet delay on N9

28.5523GPP5G performance measurementsManagement and orchestrationRelease 18TS

When I-UPF exists, the delay over N9 interface for DL/UL data packets is essential as part of the e2e packet delay, since for certain services packet delay along the way through the system may have a noticeable impact on the end user. RTT GTP data packet delay measurements for DL/UL data packets can be useful for evaluation, optimization, and performance assurance for the N9 interface between PSA UPF and I-UPF. It is also important for the performance measurement of end-to-end point of view from UE to PSA UPF. Performance degradation can happen any point, so the RTT N9 delay needs to be measured at PSA UPF and I-UPF respectively. The GTP packets are prioritized for transmitting using DSCPs, so it is necessary to measure the round-trip GTP packet delay per DSCP.