How PCEF enforce the Charging Control?

Question

Lets say we have counter 1, for a subscriber1, configured in SPR. Lets say this counter1 indicates that the QOS is throttled from 520kbps to 220kbps, when the usage exceeds the lets say 50MB in one month. This is what i understood..Now my query, is does this apply to only GBR bearers in the Subscriber ? And does it apply to all the dedicated GBR bearers ?
How is it applicable for the non GBR bearers ?

Also the PCEF, needs to send the CCR to OCS, i am not able to see how the PCEF is configured to trigger these reports back to OCS. (Is it by the CCA sent by the PCRF, that triggers this reporting from PCEF to PCRF ?)

Answer 1

The PCEF is enforcing the charging control in the following way:

• For a service data flow (defined by an active PCC rule) that is subject to charging control, the PCEF shall allow the service data flow to pass through the PCEF if and only if there is a corresponding active PCC rule with and, for online charging, the OCS has authorized credit for the charging key. The PCEF may let a service data flow pass through the PCEF during the course of the credit re-authorization procedure.
• For a service data flow (defined by an active PCC rule) that is subject to both Policy Control and Charging Control, the PCEF shall allow the service data flow to pass through the PCEF if and only if the right conditions from both policy control and charging control happen. I.e. the corresponding gate is open and in case of online charging the OCS has authorized credit for its charging key.
• For a service data flow (defined by an active PCC rule) that is subject to policy control only and not charging control, the PCEF shall allow the service data flow to pass through the PCEF if and only if the conditions for policy control are met.
• A PCEF may be served by one or more PCRF nodes. The PCEF shall contact the appropriate PCRF based on the packet data network (PDN) connected to, together with, a UE identity information (if available, and which may be IP-CAN specific). It shall be possible to ensure that the same PCRF is contacted for a specific UE irrespective of the IP-CAN used.
• The PCEF shall, on request from the PCRF, modify a PCC rule, using the equivalent PCEF behaviour as the removal of the old and the activation of the new (modified) PCC rule. The PCEF shall modify a PCC rule as an atomic operation. The PCEF shall not modify a predefined PCC rule on request from the PCRF.
• The PCEF should support predefined PCC rules.
• For online charging, the PCEF shall manage credit as defined in clause 6.1.3. The operator may apply different PCC rules depending on different PLMN. The PCEF shall be able to provide identifier of serving network to the PCRF, which may be used by the PCRF in order to select the PCC rule to be applied.
• The operator may configure whether Policy and Charging Control is to be applied based on different access point.
• The PCEF shall gather and report IP-CAN bearer usage information according to clause 6.1.2. The PCEF may have a pre-configured Default charging method. Upon the initial interaction with the PCRF, the PCEF shall provide preconfigured Default charging method if available.
• At IP-CAN session establishment the PCEF shall initiate the IP-CAN Session Establishment procedure, as defined in clause 7.2. In case the SDF is tunnelled at the BBERF, the PCEF shall inform the PCRF about the mobility protocol tunnelling header of the service data flows. In case 2a, defined in clause 7.1, the PCEF may provide charging ID information to the PCRF. If no PCC rule was activated for the IP-CAN session the PCEF shall reject the IP CAN session establishment.
• If there is no PCC rule active for a successfully established IP-CAN session at any later point in time, e.g., through a PCRF initiated IP-CAN session modification, the PCEF shall initiate an IP-CAN session termination procedure, as defined in clause 7.3.2. If the PCRF terminates the Gx session, the PCEF shall initiate an IP-CAN session termination procedure, as defined in clause 7.3.2.

For complete flow please see the specification:

3GPP TS 23.203 V8.9.0 Section 6.2.2 Policy and Charging Enforcement Function (PCEF)