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.

GnGp to LTE Handover with OI Indicator Unset Call Flow
GnGp to LTE HO with OI Indicator Unset Call Flow Description

Step

Description

1

The MME sends the Create Session Request to the GTP-EP(S11) with the following information:

  • EBI List (No LBI Information)

  • PGW control and data TEID

  • OI Indicator flag unset

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:

  • GnGp to LTE HO with OI Indicator Set

  • GnGp to LTE HO with OI Indicator Unset