DDN Throttling Call Flow
This section describes DDN Throttling call flow.

Step |
Description |
---|---|
1 |
Received DDN with throttling parameters when UE is in IDLE state. MME sends the DDN ACK to the S11-GTP-EP. |
2 |
SGW-UP sends the Sx Report Request with report type as DLDR with corresponding PDR ID to PFCP-EP. |
3 |
PFCP-EP triggers a new P-T1 transaction and routes the Sx Report Request to available service pod. PFCP-EP sends the Sx Session Report Request to the SGW-service pod. |
4 |
Started a new S-T2 transaction. Get peer information to check if DDN Throttle is active for this peer. Check if priority of this bearer is more than the configured ARP watermark SGW-service pod sends the Sx session Report Response to the PFCP-EP. |
5 |
S-T2 transaction started in step four is completed. P-T1 transaction started in step threee is completed. When a bearer found at CP for this PDR ID, the PFCP-EP sends success response to the SGW-UP. |
6 |
A new S-T3 transaction is started for the UE for which DDN is not triggered. Apply DDN algorithm to check if the DDN must be throttled. If DDN throttled, SGW-service pod sends the Sx Modification Request with Apply Action as BUFFER towards PFCP-EP. |
7, 8 |
P-T4 transaction is completed. PFCP-EP sends the Sx Session Modification Request to the SGW-UP and receives the Sx Session Modification Response from the SGW-UP. |
9 |
P-T1 transaction started in step five is completed. PFCP-EP sends Sx Modification Response to the SGW-service pod. |
10 |
S-T3 transaction started in step six is completed. SGW-service pod updates the session to CDL. |