Downlink Data Notification Failure Call Flow
This section describes the Downlink Data Notification Failure call flow.

Step |
Description |
---|---|
1 |
S11-GTP-EP pod receives DDN ACK Failure. |
2 |
The transaction started while sending the DDN Request ends. S11-GTP-EP forwards the DDN ACK Failure to the SGW-service pod. |
3 |
After receiving the DDN ACK Failure at the SGW-service pod:
Sends background IPC request for Sx Modification Request to PFCP-EP pod. Create a new transaction P-T2. |
4 |
After receiving background IPC request for Sx Modification request, PFCP-EP:
|
5 |
PFCP-EP receives the Sx Modification Response from the SGW-UP. |
6 |
The transaction P-T2 started at step three is complete. PFCP-EP pod sends background IPC response to the SGW-service pod. |
7 |
The transaction S-T1 started at step two is complete. SGW-service pod updated the CDL with buff_data_ind at bearer level flag. |
8 |
On DDN Failure timer expiry, a new transaction S-T3 is started. SGW-service pod sends background IPC request for the Sx Modification Request to the PFCP-EP pod with Apply Action as BUFFER. |
9 |
A new P-T4 transaction is created. PFCP-EP pod sends the Sx Modification Request to the SGW-UP. |
10 |
SGW-UP sends the Sx Modification Response to the PFCP-EP pod. |
11 |
The transaction P-T4 started at step eight is complete. PFCP-EP pod forwards the Sx Modification Response to the SGW-service pod. |
12 |
The transaction S-T3 started at step seven is complete. SGW-service pod updates the CDL. |