PCRF-Initiated RAR / CCAU

The following figure shows the call flow for E-UTRAN Network Credit Control Answer Update (CCAU) or Re-Authorization Request (RAR) initiated Update Bearer Request (UBR).

Call Flow for E-UTRAN Network (PCRF) CCAU/RAR Initiated UBR
Call Flow Description for PCRF-initiated CCAU or RAR
Step Description
1

PCRF sends RAR to SMF or CCAU to SMF with modified Default Bearer Qos and/or APN AMBR change.
Note
UBR is triggered for the default bearer as there’s change in either Default Bearer Qos and/or APN AMBR.

2

SMF sends Update Bearer Request to S-GW with updated Default Bearer Qos and/or updated APN AMBR.

3

SGW sends the Update Bearer Request to MME.

4

MME sends the Update Bearer Response to S-GW.

5

SGW sends the Update Bearer Response to SMF.

6

SMF sends N4 PFCP Session Modification Request to the UPF to update the Bearer level information (if default bearer Qos is changed) and/or APN AMBR QER (if APN AMBR is changed).

7

UPF sends N4 PFCP Session Modification response to SMF.