Feature Description
This section describes how the SMF handles GPRS tunneling protocol, user plane (GTP-U) error indication for the 4G sessions.
Serving Gateway (S-GW) sends GTP-U error indication message including the tunnel IDs to UPF when it receives a GTP-U message with an unknown Tunnel Endpoint Identifier (TEID). The UPF on receiving GTP-U error indication sends N4SessionReportRequest towards SMF including error indication (ERIR). The SMF retrieves EBI based on Fteid included in the N4SessionReportRequest, and initiates deletion of the session or bearer. The SMF sends Delete Bearer Request towards S-GW. On receiving the response from S-GW, the SMF sends either an N4 session modification request or N4 session release request to the UPF based on the bearer type, that is, dedicated or default bearer. CHF and PCF are also notified based on the bearer type.
Note | When the SMF receives PFCPSessionReportRequest, the IntSelfTxnN4SessRptReq message is displayed as part of the debug message. |