C.2.1.1 Online Charging Call Flow – Normal Scenario

29.2443GPPInterface between the Control Plane and the User Plane nodesRelease 17TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

Figure C.2.1.1-1 illustrates the exchanges taking place over the Sxb or Sxc reference points when applying online charging. In this example, the OCS grants quotas by chunks of 100 Mbytes and requests the CP function to request new credits when the remaining credit falls below 10 Mbytes.

Figure C.2.1.1-1: Online charging with intermediate and final quotas

1. Upon the request from the CP function, the OCS grants an intermediate quota of 100 Mbytes and requests the CP function to request a new credit when the remaining credit falls below 10 Mbytes.

2. The CP function sends a PFCP Session Modification Request to the UP function with an Update URR IE including the Volume Threshold IE set to 90 Mbytes and the Volume Quota IE set to 100 Mbytes.

3. Upon reaching the Volume Threshold (i.e. 90 Mbytes), the UP function sends a PFCP Session Report Request to the CP function with a Usage Report IE including the Usage Report Trigger set to "Volume Threshold" and the Volume Measurement set to 90 Mbytes. The UP function continues to pass on traffic until reaching the Volume Quota (i.e. an extra 10 Mbytes of traffic can be passed on).

4. Upon the request from the CP function, the OCS grants a new intermediate quota of 100 Mbytes and requests the CP function to request a new credit when the remaining credit falls below 10 Mbytes.

5. The CP function sends a PFCP Session Modification Request to the UP function with an Update URR IE including the Volume Threshold IE set to 90 Mbytes and the Volume Quota IE set to 100 Mbytes. If the UP function had forwarded e.g. 5 Mbytes of traffic since the last usage report, the UP function knows that it shall send the next usage report upon passing on an extra 85 Mbytes of traffic.

6. Upon reaching the Volume Threshold (i.e. 90 Mbytes), the UP function sends a PFCP Session Report Request to the CP function with a Usage Report IE including the Usage Report Trigger set to "Volume Threshold" and the Volume Measurement set to 90 Mbytes. The UP function continues to pass on traffic until reaching the Volume Quota (i.e. an extra 10 Mbytes of traffic can be passed on).

7. Upon the request from the CP function, the OCS grants a new final quota of 50 Mbytes and requests the CP function to terminate the service or to redirect the traffic towards a redirect destination when the quota is consumed.

8. The CP function sends a PFCP Session Modification Request to the UP function with an Update URR IE including the Volume Quota IE set to 50 Mbytes. If the UP function had forwarded e.g. 5 Mbytes of traffic since the last usage report, the UP function knows that it shall send the next usage report upon passing on an extra 45 Mbytes of traffic.

9. Upon reaching the Volume Quota (i.e. 50 Mbytes), the UP function sends a PFCP Session Report Request to the CP function with a Usage Report IE including the Usage Report Trigger set to "Volume Quota" and the Volume Measurement set to 50 Mbytes. The UP function stops passing on traffic.

10. Upon being notified that the final quota has been reached, the CP function terminates the service (e.g. by preventing the traffic of the corresponding SDF to further pass on in the UP function) or redirects the traffic towards a redirect destination by provisioning a Redirect Information IE within the FAR associated to the traffic.

Figure C.2.1.1-2 illustrates the exchanges taking place over the Sxb or Sxc reference points when applying online charging and the UP function supports being provisioned with the Quota Action to apply when reaching quotas. This example is similar to the previous one, but the CP function provisions the UP function with the action to apply when reaching the final quota.

Figure C.2.1.1-2: Online charging with Quota Action provisioned in the UP function

1 to 7′. Same as for figure C.2.1.1-1.

8. The CP function sends a PFCP Session Modification Request to the UP function with a Create FAR IE provisioning the action the UP function shall apply when reaching the quota, and with an Update URR IE including the Volume Quota IE set to 50 Mbytes and the FAR ID for Quota Action IE set to the new FAR ID). If the UP function had forwarded e.g. 5 Mbytes of traffic since the last usage report, the UP function knows that it shall send the next usage report upon passing on an extra 45 Mbytes of traffic.

10. The UP function applies the quota action provisioned at step 8, i.e. it stops forwarding packets or it redirects the traffic towards a redirect destination, according to the FAR identified in the FAR ID for Quota Action.