• UCC cnSGW-C - Release Change Reference
  • About cnSGW
    • 5G Architecture
    • cnSGW-C Overview
    • Deploying and Configuring cnSGW-C through Operations Center
    • Smart Licensing Support
    • cnSGW-C Rolling Software Update
    • Pods and Services Reference
    • 3GPP RAN/NAS Cause Codes Support
    • Access Bearer Release Support
    • APN Profile Support
    • Change Notification Request Handling
    • Clear Subscriber Request
    • Context Replacement Support
    • Dedicated Bearer Support
    • Delete Bearer and Delete Session Request
    • Downlink Data Notification
      • Feature Summary and Revision History
      • Feature Description
      • DDN Message Handling
        • Feature Description
        • How it Works
          • Call Flows
            • Downlink Data Notification Success Call Flow
            • Downlink Data Notification Failure Call Flow
            • No User Connect Retry Timer Call Flow
        • Feature Configuration
      • Control Messages Triggered DDN Support
      • DDN Advance Features
    • DSCP Marking Support
    • Dynamic Routing by Using BGP
    • Emergency Call Support
    • Extended and Non-Standard QCI Values Support and Validation
    • eMPS/WPS Support
    • Failure and Error Handling Support
    • GTPC and Sx Path Management
    • GTPU Error Indication
    • GTPU Path Failure
    • GTPv2 and Sx Messages Retransmission and Timeout Handling
    • GTPv2 Load/Overload Support
    • GTPv2 Message Validation
    • IDFT Support
    • Idle Session Timeout Settings
    • Initial Attach Support
    • Inter System RAT Handover
    • Intra-MME and Inter-MME Handover Procedures
    • MCC/MNC Configuration in the SGW Service
    • Message Interactions Support
    • Modify and Delete Bearer Command Support
    • Modify Bearer Request Support
    • Monitor Subscriber and Protocol Support
    • Multiple PDN Attach or Detach Procedures
    • Performance Optimization Support
    • Presence Reporting Area
    • Redundancy Support
    • Service Configuration Enhancements
    • SGW Charging Support
    • SGW Relocation Support
    • Sx Load/Overload Control Handling
    • Stale Session Handling and Clearing
    • Update Bearer Request and Response
    • UPF Selection Support
    • VoLTE Call Prioritization
    • cnSGW-C Troubleshooting
  • Sample cnSGW Configuration
  • Statistics and KPI Reference

Downlink Data Notification Failure Call Flow

This section describes the Downlink Data Notification Failure call flow.

Downlink Data Notification Failure Call Flow
Downlink Data Notification Failure Procedure Call Flow Description

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:

  • Decides the paging state based on the cause received:

    • EGTP_CAUSE_CONTEXT_NOT_FOUND: Submit internal transaction for call deletion.

    • EGTP_CAUSE_UNABLE_TO_PAGE_UE

    • EGTP_CAUSE_UNABLE_TO_PAGE_UE_DUE_TO_SUSPENSION

    • EGTP_CAUSE_UE_ALREADY_REATTACHED

    • EGTP_CAUSE_TEMP_REJECTED_DUE_TO_HANDOVER_IN_PROGRESS

  • Checks if the PDNs are in connected state to initiate the Sx Modify Request. Minimum one one PDN should be in the CONNECTED state.

  • Submits internal transactions to handle these paging failure causes.

  • Ends the current procedure and transaction.

  • In the new transaction of handling paging failures, derives all the PDNs for which you want to send Sx Modify request.

  • Based on the paging state, derives paging action and send Sx Modify Request based on the action required.

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:

  • Starts a new P-12 transaction.

  • Sends the o the SGW-UP.

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.

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