Static and Predefined Rules for Charging
Configuration of static or predefined rules is similar to the procedures on SMF and UPF. The layout of configuration is as follows:
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Rulebase: A one-to-many rulebase is configurable. For a single PDU session, you can activate a single rulebase any time. PCF can activate the rulebase at SMF by sending the rulebase name in the PCC rule.
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Ruledef: Each rulebase 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.
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Charging Action: Contains QoS and charging information.
The SMF derives charging data for each charging action in the rulebase. Charging action associated to static rules in the rulebase is immediately derived and updated in the PDU context. Charging action that is associated to predefined rules is derived and updated when PCF activates the specific predefined rule at SMF.
The charging action derived URR has the following behavior:
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Online charging is identified by the "cca charging credit " configuration under charging action.
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Offline charging is identified by the "billing action egcdr " configuration under charging action.
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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.
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The SMF, unlike the dynamic case, does not send the Create URR immediately for charging data that is derived from the configured rules.
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Using the online charging method, the UPF sends usage report with the "Start" trigger. The SMF uses CHF to derive the quota for the RG and relays the same information to the UPF in the Update URR message.
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You can configure the UPF threshold at a rulebase level. It creates a rulebase-level URR that is linked to all ruledef-level URR within the rulebase.