Call Flow

This section describes the call flow for the User Plane Deactivation of a PDU session.

The following figure illustrates the User Plane Deactivation call flow.

Deactivation of the User Plane Connection Call Flow
Deactivation of the User Plane Connection Call Flow Description

Step

Description

1

NF Service Consumer requests the SMF to deactivate the user plane connection of the PDU session by sending a POST request with the following information:

  • upCnxState attribute set to DEACTIVATED.

  • User location and user location timestamp.

  • Cause of the user plane deactivation. The cause may indicate a cause received from the 5G-AN or due to an AMF internal event.

  • Other information (if required).

2

SMF deactivates and releases the N3 tunnel of the PDU session after receiving such a request. SMF initiates the PFCP Session Modification procedure towards UPF with downlink FAR updated with the following options:

  • Buffering Action is enabled without remote node "forwarding parameters" details, such as IP address and GTP-U F-TEID.

Note

NOCP (Notify the CP function) is not enabled. Support for notification is not supported on SMF.

3

SMF sets the upCnxState attribute to DEACTIVATED for the PDU session after receiving successful response from the UPF node.

4

SMF initiates a 200 OK response towards AMF including the upCnxState attribute set to DEACTIVATED.