AMF-initiated PDU Session Release
The AMF-initiated PDU session release procedure allows the AMF to initiate the release of a PDU session.
The following figure depicts the AMF-initiated PDU session release call flow.

Step | Description |
---|---|
1 |
The AMF sends SmContextReleaseRequest. |
2, 3 |
The SMF sends N4SessionReleaseRequest to the UPF. The UPF sends response for the same. |
4 |
The SMF sends SmContextReleaseResponse to the AMF. |
5, 6 |
The SMF sends delete charging request to the CHF. The CHF responds back to the SMF with delete response. |
7, 8 |
The SMF sends delete request to the PCF. The PCF responds back to the SMF with delete response. |
9, 10 |
The SMF sends UDM deregistration request. The UDM responds back to the SMF with deregistration response. |