Call Flow

Activation of the User Plane Connection of a PDU Session Call Flow
Activation of the User Plane Connection of a PDU Session Call Flow Description

Step

Description

1

AMF requests the SMF to activate the user plane connection of the PDU session by sending a POST request with the following information:

  • upCnxState attribute set to ACTIVATING.

  • User location, user location timestamp, and access type associated to the PDU session (if modified)

  • Other information (if required).

2

SMF starts activating the N3 tunnel of the PDU session after receiving the request. SMF returns a 200 OK response including the following information:

  • upCnxState attribute set to ACTIVATING.

  • N2 SM information to request the 5G-AN to assign resources to the PDU session including the transport layer address and tunnel endpoint of the uplink termination point for the user plane data for this PDU session that is UPF's GTP-U F-TEID for uplink traffic.

3

AMF requests the SMF by sending POST request, with the following information:

  • SM information received from the 5G-AN, including the transport layer address and tunnel endpoint of the downlink termination point for the user data for this PDU session, 5G-AN's GTP-U F-TEID for downlink traffic if the 5G-AN succeeded in establishing resources for the PDU sessions.

4

SMF initiates PFCP session modification procedure towards UPF with down link FAR updated with following options:

  • Forwarding Action is enabled with remote node “forwarding parameters” details like IP address and GTP-U F-TEID.

5

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

6

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