Offline SDF Usage Report in N4 Session Report

The Offline SDF or Bearer URRs are present on UPF with values like Thresholds and so on. SDF Volume/Time threshold is hit at the UPF for SDF level URRs. UPF relays usage to the SMF along with usage reporting trigger information. The following call flow and procedure describes the Asynchronous Usage report for offline Bearer recalculation.

Call Flow Description for Async Usage Report Offline Bearer Recalculation
Step Description
1

UPF initiates N4 Session report Exchange with SMF.

2

UPF sends N4 Session Deletion Response with offline Usage report.

3

SMF sends GTPP Data Transfer Request with SDF Containers.

  • If the Offline usage report is received in the N4 Session Deletion Response, then the SMF sends a GTPP Data Record Transfer Request for default with SDFs container with volume usage and serviceConditionChange—one for each RG+service ID only if the maximum charging condition is reached.

  • If the Offline usage report that is received is without measurement for SDF level time threshold in the N4 Session Report Request, then a GTPP Data Record Transfer message does not get exchanged with OFCS.

4

SMF receives GTPP Data Record Transfer Response from OFCS.

5

After receiving the Offline SDF usage, if the SMF sends GTPP Data Record Transfer Request due to maximum charging condition, then N4 Modification Request with Update Bearer level URR (Bearer Recalculate) is sent to the UPF.

6

UPF sends N4 Modification Response.