Change Notification Request Call Flow
This section describes the change notification request and the response call flow.

Step |
Description |
---|---|
1 |
The MME sends a Create Session Request towards GTP-EP(S11). |
2 |
The GTP-EP(S11) forwards the Create Session Request to the SGW-SVC. |
3 |
The SGW-SVC sends the Sx Establishment Request to the UPF. |
4 |
The UPF responds to the request with the SX Establishment Response directed towards the SGW-SVC. |
5 |
The MME and the PGW establish the sessions and start exchanging data. |
6 |
The MME and the PGW create the dedicated bearer and start exchanging data. |
7 |
The MME sends the Change Notification Request to the GTP-EP. |
8 |
The GTP-EP forwards the Change Notification Request to the SGW-SVC. If ULI or UCI changes are valid in the connection request (CNREQ), the PDN is updated. The GTP-EP sends the Sx Modification Request with the URR query after checking the secondary RAT usage. |
9 |
The SGW-SVC sends the Sx Modification Request with the URR query to the Proto-SXA. |
10 |
The Proto-SXA forwards the Sx Modification Request with the URR query to the UPF. |
11 |
The UPF responds to the request with the Sx Modification Response, with the usage report to the Proto-SXA. |
12 |
The Proto-SXA forwards the Sx Modification Response with the usage report to the SGW-SVC. |
13 |
The SGW-SVC sends the Change Notification Request to the GTPC-S5. |
14 |
The GTPC-S5 forwards the Change Notification Request to the PGW. |
15 |
The PGW responds with the Change Notification Response to the GTPC-S5. |
16 |
The GTPC-S5 forwards the Change Notification Response to the SGW-SVC. |
17 |
The SGW-SVC sends the Change Notification Response to the GTP-EP(S11). |
18 |
The GTP-EP(S11) forwards the Change Notification Response to the MME. |