Feature Description

The SMF triggers Packet Forwarding Control Protocol (PFCP) Node Report procedure as per the 3GPP TS 29.244, section 6.2.9. The UPF sends this report to indicate a user plane path failure affecting all the PFCP sessions towards a remote GTP-U peer. The UPF notifies this failure to the SMF through User Plane Path Failure Report (UPFR). When the UPF detects a GTP-U path failure, the SMF clears the PDU sessions belonging to the GTP-U peer and UPF node ID.

In addition to the existing UPF session report, the SMF supports the following new proprietary report types:

  • Graceful Termination Report (GTER) – This type of report is sent when the UPF is unable to recover a PDU session during Session Recovery (SR) or Inter-Chassis Session Recovery (ICSR).

  • Session Replacement Report (SRIR) – This type of report is sent to replace a session due to identical GTP-U tunnel endpoint identifier (TEID) allocated by gNB. This is possible with the restart of gNB. In this case, the old session with the same TEID is deleted.

  • Self-protection Termination Report (SPTER) – This type of report is sent to terminate a PFCP session during overload scenarios.