GnGp to LTE Handover with OI Indicator Unset Call Flow
This section describes the GnGp to LTE Handover with Operation Indication (OI) Indicator Unset call flow.

Step |
Description |
---|---|
1 |
The MME sends the Create Session Request to the GTP-EP(S11) with the following information:
|
2 |
The GTP-EP(S11) forwards the Create Session Request to the SGW-SVC. |
3 |
The SGW-SVC sends the Sx Session Establishment Request to the Protocol-Sxa. |
4 |
The Protocol-Sxa sends the Sx Establishment Response to the SGW-SVC. |
5 |
The SGW-SVC sends the Create Session Response to the GTP-EP(S11). |
6 |
The GTP-EP(S11) forwards the Create Session Response to the MME. |
7 |
The MME sends the Modify Bearer Request to the GTP-EP(S11). |
8 |
The GTP-EP(S11) forwards the Modify Bearer Request to the SGW-SVC. |
9 |
The SGW-SVC sends the Sx Modification Request to the Protocol-Sxa. |
10 |
The Protocol-Sxa sends the Sx Modification Response to the SGW-SVC. |
11 |
The SGW-SVC sends the Modify Bearer Request to the GTP-EP(S5). |
12 |
The GTP-EP(S5) forwards the Modify Bearer Request to the UDP-Proxy. |
13 |
The UDP-proxy forwards the Modify Bearer Request to the PGW. |
14 |
The PGW sends the Modify Bearer Response with the default EBI information to the UDP-Proxy. |
15 |
The UDP-Proxy forwards the Modify Bearer Response to the GTP-EP(S5). |
16 |
The GTP-EP(S5) forwards the Modify Bearer Response to the SGW-SVC. |
17 |
The SGW-SVC forwards the Modify Bearer Response to the GTP-EP(S11). |
18 |
The GTP-EP(S11) forwards the Modify Bearer Response to the MME. The S1 SGW FTEID is the same as the S1-U SGW FTEID sent in Create Session Response from the SGW-SVC to the MME. The SGW-SVC can now send the downlink packets to the eNodeB, and the switching of the data path from Wi-Fi to LTE occurs after the Modify Bearer Response. |
Note | cnSGW-C clears the call when the received default EBI in the Modify Bearer Response differs with the first EBI in the following scenarios:
|