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.
| 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. |