Wi-Fi to 5G Handover with Alternate RAT Tunnel Creation Call Flow

This section describes the call flow of Wi-Fi to 5G handover with an alternate RAT tunnel creation.

Wi-Fi to 5G Handover with Alternate RAT Tunnel Creation Call Flow
Wi-Fi to 5G Handover with Alternate RAT Tunnel Creation Call Flow Description
Step Description
1

UE sends the PDU Session Establishment Request to AMF.

2

AMF Nsmf PDU Session Create SMContext Request to SMF+PGW-C. This request is for the existing PDU session.

The SMF+PGW-C sends the 200 OK message.

3

SMF+PGW-C sends the Policy Update Request to PCF.

4

PCF sends the Policy Update Response to SMF+PGW-C.

5

SMF+PGW-C sends the Charging Update Request to CHF.

6

CHF sends the Charging Update Response to SMF+PGW-C.

7

SMF+PGW-C sends the EBI assignment request to AMF.

8

AMF sends the EBI assignment Response to SMF+PGW-C.

9

SMF+PGW-C sends the N1N2Message Transfer (PDU Establishment Accept) message to AMF.

10

AMF sends the 200 OK response to SMF+PGW-C.

11

AMF sends the SMContext Update Request (N2 message) to SMF+PGW-C.

12

SMF+PGW-C sends the N4 Modification Request to UPF. This request includes details on DL FAR update and Query URR of the Wi-Fi tunnel.

13

UPF sends the N4 Modification Response to SMF+PGW-C.

14

SMF+PGW-C sends the SMContext Update Response, which is 204 OK to AMF. SMF+PGW-C

SMF+PGW-C includes details on policy, charging updates, and the released EBI list or failed QFI handling information.