5.12 Change the chargeable party at session set-up or during the session procedure

23.6823GPPArchitecture enhancements to facilitate communications with packet data networks and applicationsRelease 17TS

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

5.12.1 Set the chargeable party at session set-up

This clause describes the signalling flow for setting the chargeable party at AS session set-up. The SCS/AS may either request to sponsor the traffic from the beginning or may request to become the chargeable party at a later point in time.

Figure 5.12.1-1: Set the chargeable party at AS session set-up

1. When setting up the connection between the AS and UE, the SCS/AS may request to become the chargeable party for the session to be set up by sending a Set chargeable party request message (SCS/AS Identifier, Description of the application flows or External Application Identifier, sponsor information, Sponsoring Status, Reference ID) to the SCEF, including optionally a usage threshold. The Sponsoring Status indicates whether sponsoring is started or stopped, i.e. whether the 3rd party service provider is the chargeable party or not. The Reference ID parameter identifies a previously negotiated transfer policy for background data transfer as defined in clause 4.5.9. The SCEF assigns a TLTRI to the Set chargeable party request.

2. The SCEF authorizes the SCS/AS request to sponsor the application traffic and stores the sponsor information together with the SCS/AS Identifier and the TLTRI. If the authorisation is not granted, step 3 is skipped and the SCEF replies to the SCS/AS with a Result value indicating that the authorisation failed.

NOTE 1: Based on operator configuration, the SCEF may skip this step. In this case the authorization is performed by the PCRF in step 3.

3. The SCEF interacts with the PCRF by triggering a PCRF initiated IP-CAN Session Modification as described in clause 7.4.2 of TS 23.203 [27] and provides IP filter information, sponsored data connectivity information (as defined in TS 23.203 [27]), Reference ID (if received from the SCS/AS) and Sponsoring Status (if received from the SCS/AS) to the PCRF.

NOTE 2: The SCEF maps the Sponsoring Status to existing Rx parameters.

The PCRF determines whether the request is allowed and notifies the SCEF if the request is not authorized. If the request is not authorized, SCEF responds to the SCS/AS in step 4 with a Result value indicating that the authorization failed.

As specified in TS 23.203 [27], the PCRF determines the PCC rule(s) for the specified session including charging control information. Charging control information shall be set according to the Sponsoring Status (if received over Rx), i.e. either indicating that the 3rd party service provider is the chargeable party or not. The PCC rule(s) for the specified session shall then be provided to the PCEF. In the case of online charging and depending on operator configuration, the PCEF may request credit when the first packet corresponding to the service is detected or at the time the PCC Rule was activated.

The PCRF notifies the SCEF that the request is accepted.

4. The SCEF sends a Set chargeable party response message (TLTRI, Result) to the SCS/AS. Result indicates whether the request is granted or not.

5.12.2 Change the chargeable party during the session

This clause describes the signalling flow for changing the chargeable party during an ongoing AS session, i.e. the SCS/AS starting or stopping to sponsor the application traffic.

Figure 5.12.2-1: Change chargeable party during an AS session

1. For the ongoing AS session, the SCS/AS may send a Change chargeable party request message (SCS/AS Identifier, TLTRI, Sponsoring Status, Reference ID) to the SCEF, including optionally a usage threshold. The Sponsoring Status indicates whether sponsoring is enabled or disabled, i.e. whether the 3rd party service provider is the chargeable party or not. The Reference ID parameter identifies a previously negotiated transfer policy for background data transfer as defined in clause 4.5.9. The TLTRI provided in the Change chargeable party request message is set to the TLTRI that was assigned, by the SCEF, to the Set chargeable party request.

2. The SCEF authorizes the SCS/AS request of changing the chargeable party. If the authorisation is not granted, step 3 is skipped and the SCEF replies to the SCS/AS with a Result value indicating that the authorisation failed.

NOTE 1: Based on operator configuration, the SCEF may skip this step. In this case the authorization is performed by the PCRF in step 3.

3. Based on the SCS/AS Identifier and the TLTRI the SCEF determines the relevant Rx session and interact with the PCRF by triggering a PCRF initiated IP-CAN Session Modification as described in clause 7.4.2 of TS 23.203 [27]. The SCEF provides sponsored data connectivity information (as defined in TS 23.203 [27]), Reference ID (if received from the SCS/AS), and the Sponsoring Status to the PCRF.

NOTE 2: The SCEF maps the Sponsoring Status to existing Rx parameters.

The PCRF identifies the affected PCC rule(s) and reacts based on their current status. If the traffic is subject to subscriber charging in the PCEF and the PCRF receives a Sponsoring Status indicating that sponsoring is started, the PCC rule(s) for the specified session shall be modified so that the charging control information indicates that the 3rd party service provider is charged for the traffic. If the traffic is subject to 3rd party charging in the PCEF and the PCRF receives a Sponsoring Status indicating that sponsoring is stopped, the PCC rule(s) for the specified session shall be modified so that the charging control information indicates that the 3rd party service provider is no longer charged for the traffic. As specified in TS 23.203 [27], PCRF modifies the PCC rule(s) of the service data flow accordingly and provides them to the PCEF. In the case of online charging and depending on operator configuration, the PCEF may request credit when the first packet corresponding to the service is detected or at the time the PCC Rule was activated.

The PCRF notifies the SCEF that the request is accepted.

4. The SCEF sends a Change chargeable party response message (Result) to the SCS/AS. Result indicates whether the request is granted or not.