PFCP Session Reporting Procedure

The UPF uses PFCP Session Reporting procedure to report information that is related to the PFCP session to the SMF (usage report IE). Once the threshold hits the volume, time or event measurement and sets the corresponding trigger for reporting, the message is sent to the SMF by the UPF.

The following call flow depicts the PFCP Session Reporting procedure.

StepDescription
1
  • Once the provisioned threshold is met (for time, volume or event, and trigger is set for reporting), the UPF sends PFCP Session Report Request with usage report IE and usage details for volume, time, or threshold.

  • The custom Information Element (IE) called Recalculate Measurement is added to the Update-URR IE (for URR-ID: Gz-Bearer) to support the PGWCDR generation due to the Max-LOSDV condition with the N4 Session Modify Request. After receiving the IE, UPF reconciles the Volume and Duration of the URR according to the URR-ID present inside the IE.

2The SMF responds with PFCP Session Modification Response with success or failure message. No failure handling is needed on the UPF.
3The SMF interacts with the network function, which triggered this procedure. For instance, AMF or PCF.