Wi-Fi to LTE Handover Call Flow

This section describes the Wi-Fi to LTE Handover call flow.

Wi-Fi to LTE Handover Call Flow
Wi-Fi to LTE Handover Call Flow Description

Step

Description

1

MME sends create Session Request to SGW.

2

SGW sends Sx Establishment Request to UPF1.

3

SGW receives Sx Establishment Response from SMF.

4

SGW sends Create Session Request to SMF. SMF selects same UPF.

5

SMF sends Sx Establishment Request to UPF1.

6

SMF receives Sx Establishment Response from UPF1.

7

SMF sends Create Session Response to SGW.

8

SGW sends Sx Mod Request to UPF1.

9, 10

SGW receives Sx Mod Response from UPF1 and forwards to MME.

11

Modify Bearer procedure takes place and off-loaded call to Wi-Fi.

ePDG sends Create Session Request to SGW.

12

SMF sends Sx Mod Request to UPF1.

13

SMF receives Sx Mod Response from UPF1.

14

ePDG receives Create Session Response from SGW.

15

Call moved to Wi-Fi to clear at SGW.

MME sends Delete Session Request to SGW.

16

MME receives Delete Session Response from SGW after performing call clear procedure.

17

MME sends Create Session Request to SGW.

18

SGW sends fetch UPF (UPF1) info request to SMF after checking SMF as same cluster as cnSGW-C.

19

SGW receives UPF (UPF1) Info Response from SMF.

20

SGW sends Sx Establishment Request to UPF1.

21

SGW receives Sx Establishment Response from UPF1.

22

SGW sends Create Session Request with SGWU=UPF1 to UPF1 and performs call setup procedure.