Static and Predefined Rules for Charging

Configuration of static/predefined rules is similar to the procedures on SMF and UPF. The layout of configured is as follows:

  1. Rulebase: A one-to-many rule base is configurable. For a single PDU session, a single rule base can be activated at a given time. The rule base can be activated at SMF by the PCF by sending the rule base name in the PCC rule.

  2. Ruledef: Each rule base can have one-to-many ruledef configurations. A ruledef can either be of static or predefined type. Each ruledef is assigned to a charging action.

  3. Charging Action: Contains QoS and charging information.

The SMF derives charging data for each charging action in the rule base. Charging action associated to static rules in the rule base is immediately derived and updated in the PDU context. Charging action associated to predefined rules is derived and updated when the said predefined rule is activated at SMF from PCF.

The charging action derived URR has the following behavior:

  • Online charging is identified by the "cca charging credit " configuration under charging action.

  • Offline charging is identified by the "billing action egcdr " configuration under charging action.

  • Armed triggers for volume-limit and time-limit are under the gtpp group configuration, under APN. The UPF automatically detects these values and sends the respective usage reports.

  • The SMF, unlike the dynamic case, does not send the Create URR immediately for charging data that is derived from configured rules.

  • Only when charging action is configured with "cca charging credit preemptively-request ", the SMF sends the Create URR message. In all other cases, the SMF does not send the Create URR.

    Note

    This CLI is not qualified in the current release.

  • For URR derived from configured rules, the SMF generates URR-ID from "urr-list ". This configuration has one URR-ID for each set of RG and service ID.

    Therefore, when the UPF sends the usage report for a URR ID, the SMF does not identify the corresponding URR, RG/service ID to be used for reporting toward the CHF.

  • Using the online charging method, the UPF sends usage report with trigger "Start". The SMF uses CHF to derive the quota for the RG and relays the same information to the UPF in the Update URR message.

  • The UPF threshold can be configured at a rule base level. It creates a rulebase-level URR that is linked to all ruledef-level URR within the rule base.