N5 Interface
With the N7 interface being 3GPP December 2018 specification compliant, PCF supports the notification of rule status of the dedicated bearer rules. You can configure this support with the new "ruleReports" parameter, which is sent in the SmPolicyUpdateRequest message. This parameter consists of the report of rule status as successful or failed.
When IMS initiates multimedia calls, PCF installs the dedicated bearer rules on the SMF nodes. SMF enforces these rules and provides the status of these rules to PCF in the ruleReports parameter.
Following are some of the subparameters of the ruleReports parameter that the feature supports:
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Array of pccRuleIds
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Rule Status
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Failure Code
The N5 (Rx) interface works in the following way:
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If the AAR message on the N5 interface receives the “INDICATION_OF_SUCCESSFUL_RESOURCES_ALLOCATION (8)” action, PCF sends the “SUCC_RES_ALLO” event trigger to SMF in the SmPolicyUpdateNotify message.
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SMF sends the status report in the SmPolicyUpdateRequest message. When PCF sends the “SUCC_RES_ALLO” event trigger, ruleReports parameter consists of the rules with the Rule Status as Active. Rule Status value can either be “Active” or “Inactive”. PCF sends these rule reports through Rx_RAR toward AF.
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The ruleReports parameter also consists of “Inactive” rules along with their Failure Status. If some rules are Inactive, PCF sends the failure report of these in Rx_RAR to AF. If all the rules are Inactive, PCF sends the failure report of these rules in Rx_ASR to AF.
NotePCF sends the failure report to AF if the Rx session has already requested the "INDICATION_OF_FAILED_RESOURCES_ALLOCATION(9)" specific action in AAR.
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PCF handles reporting of both Active and Inactive rule status in the same ruleReports along with the “SUCC_RES_ALLO” event trigger.
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If multiple Inactive rules exist under ruleReports with multiple failureCode, then all the rules are mapped to only single Specific-Action. Then, PCF sends these rules in the Rx_RAR (or abort-cause for Rx_ASR).