MME-initiated Deletion Call Flow

This section explains the processing of MME-initiated dedicated bearer deletion call flow when the procedure SLA timer expires. Upon the expiry of procedure SLA timer for Delete Bearer Command (DBC), the SMF sends Delete Bearer Failure Indication.

Note

The SMF uses procedure SLA configuration for S5 or S2b interface based on the RAT type.

The following figure depicts the dedicated bearer deletion call flow initiated by MME upon receipt of Delete Bearer Command.

MME-initiated Deletion Call Flow

The following table describes the processing performed at each stage when the SLA timer expires:

Processing of MME-initiated Deletion During SLA Timer Expiry

Timeline or Slice availability

Request or Event

Stage - Failure

Timeout due to Transaction SLA

Procedure SLA as configured

Delete Bearer Command

Idle

Send Delete Bearer Failure Indication

Procedure SLA as configured

PCF update request

Send Delete Bearer Failure Indication

Procedure SLA as configured

First N4 Modification Request

Async DBR

Sync N4 to remove tunnels for the deleted rules. Perform sync procedure to avoid loss of usage reports which the UPF sends N4 modification response for the deleted flows.

Procedure SLA as configured

Delete Bearer Request

Sync N4 to remove tunnels for the deleted rules. Perform sync procedure to avoid loss of usage reports which the UPF sends N4 modification response for the deleted flows.

Procedure SLA as configured

Second N4 Modify Request

Treat as procedure success. Then, update PDU context.

Procedure SLA as configured

Charging Update Request

Treat as procedure success. Then, update PDU context.