Each PCC rule for which Usage-Monitoring is required, contains Monitoring-Key AVP.
Charging-Rule-Definition ::= < AVP Header: 1003 >
{ Charging-Rule-Name }
*[ Flow-Information ]
[ Flow-Status ]
[ QoS-Information ]
[ Precedence ]
[ Monitoring-Key]
*[ AVP ]
Usage-Monitoring for PCC rules is implemented through a dynamic policer. The policer is instantiated at the time when the PCC rule with Monitoring-Key AVP is installed.
The same monitoring-key can be used in multiple PCC rules assuming that these rules are for the same direction. In other words, the charging rule is rejected if the same monitoring-key is used for ingress and egress.