Cisco ASR 5000 Administration Manual page 67

Gx Interface Support
In 12.0 and later releases, monitoring of usage based on input/output octet threshold levels is supported. Usage
is reported based on the enabled threshold level. If multiple levels are enabled, usage will be reported on all the
enabled levels even if only one of the levels is breached. Monitoring will be stopped on the missing threshold
levels in the response for the usage report from PCRF (expected to provide the complete set again if PCRF
wants to continue monitoring on the multiple levels enabled earlier).
Total threshold level along with UL/DL threshold level in the GSU AVP is treated as an error and only total
threshold level is accepted.
 Usage Monitoring at Flow Level: PCRF subscribes to the flow-level volume reporting over Gx by sending the
Usage-Monitoring-Information AVP with the usage threshold level set in Granted-Service-Unit AVP and
Usage-Monitoring-Level AVP set to PCC_RULE_LEVEL(1). Monitoring Key is mandatory in case of a flow-
level monitoring since the rules are associated with the monitoring key and enabling/disabling of usage
monitoring at flow level can be controlled by PCRF using it. After the AVPs are parsed by DPCA, IMSA
updates the information to ECS. Once ECS is updated usage monitoring is started and constantly checked with
the usage threshold whenever the data traffic is present.
Usage monitoring is supported for static, predefined rules, and dynamic rule definitions.
 Usage Monitoring for Static Rules: In the case of static rules, the usage reporting on last rule removal
 Usage Monitoring for Predefined Rules: If the usage monitoring needs to be enabled for the predefined
 Usage Monitoring for Dynamic Rules: If the usage monitoring needs to be enabled for dynamic
Usage Reporting
Usage at subscriber/flow level is reported to PCRF under the following conditions:
 Usage Threshold Reached: PCEF records the subscriber data usage and checks if the usage threshold provided
by PCRF is reached. This is done for both session and rule level reporting.
For session-level reporting, the actual usage volume is compared with the usage volume threshold.
For rule-level reporting the rule that hits the data traffic is used to find out if the monitoring key is associated
with it, and based on the monitoring key the data usage is checked. Once the condition is met, it reports the
usage information to IMSA and continues monitoring. IMSA then triggers the CCR-U if "USAGE_REPORT"
trigger is enabled by the PCRF. The Usage-Monitoring-Information AVP is sent in this CCR with the "Used-
Service-Unit" set to the amount of data usage by subscriber.
OL-27210-02
associated with the monitoring key is not applicable. In this case only the usage monitoring
information is received from the PCRF.
rules, PCRF sends the rule and the usage monitoring information containing the monitoring key and
the usage threshold. The Monitoring key should be same as the one pre-configured in PCEF for that
predefined rule. There can be multiple rules associated with the same monitoring key. Hence enabling
a particular monitoring key would result in the data being tracked for multiple rules having the same
monitoring key. After DPCA parses the AVPs IMSA updates the information to ECS. Once ECS is
updated usage monitoring is started and constantly checked with the usage threshold whenever the
data traffic is present.
ruledefs, PCRF provides the monitoring key along with a charging rule definition and the usage
monitoring information containing the monitoring key and the usage threshold. This would result in
the usage monitoring being done for all the rules associated with that monitoring key. After DPCA
parses the AVPs, IMSA updates the information to ECS. Once ECS is updated, the usage monitoring
is started and constantly checked with the usage threshold whenever the data traffic is present.
Monitoring key for dynamic ruledef is dynamically assigned by PCRF which is the only difference
with predefined rules in case of usage monitoring.
Cisco ASR 5000 IP Services Gateway Administration Guide ▄
Rel. 7 Gx Interface ▀
67