Contents

1   Alarm Description

The CSCF, Throttling of Diameter Traffic on Cx/Dx Interface Initiated alarm is raised to indicate the initiation of throttling of diameter traffic on the Cx/Dx interface. The diameter traffic is throttled if Home Subscriber Server (HSS) overload is detected, which means that the CSCF acts as if HSS would have responded with overload even though the CSCF does not send the request to HSS.

Overload is detected when the percentage of busy responses received from the node/realm over a configurable time period (cscfThrottlingWindowLength) exceeds a configurable threshold (cscfUpperThrottlingThreshold).

The alarm is associated to the Performance Management counter cscfThrottledHssRequests.

The alarm is raised when the number of cscfThrottledHssRequests has reached or exceeded its configured thresholdHigh within the time period configured by thresholdRateOfVariation and granularityPeriod.

The alarm is automatically ceased when it reaches or goes below the configured thresholdLow value.

The default values related to this alarm are thresholdRateOfVariation=PER_GP, granularityPeriod=FIVE_MIN, thresholdHigh=1, and thresholdLow=0. This means that when the counter value is 1 or higher, the alarm is raised when the Granularity Period is ended. The alarm ceases when the counter cscfThrottledHssRequests has reached a value of 0 at the end of a Granularity Period.

Note:  

The thresholds for raising and ceasing this alarm are configurable where it can be turned on and off. The default Distinguished Name for the thresholds is ManagedElement=<node_name>, SystemFunctions=1, Pm=1, PmJob=CscfCxIfStatisticsThreshold, MeasurementReader=cscfThrottledHssRequestsMeasReader, PmThresholdMonitoring=cscfThrottledHssRequests.

Threshold values cannot be changed once they have been set. To change a threshold, first the PmThresholdMonitoring instance must be deleted and recreated with required thresholdHigh and thresholdLow.

For more information, refer to Performance Management.

Note:  

This alarm can appear as a result of maintenance activity.

2   Procedure

2.1   Handle Alarm CSCF, Throttling of Diameter Traffic on Cx/Dx Interface Initiated

Prerequisites

• This instruction references the following documents:
  • CSCF Configuration Management
  • Managed Object Model (MOM)
• No tools are required.
• The following condition must apply:
  • The alarm is raised.

Steps

Note:  

If the reason for the alarm has disappeared after the Granularity Period, the alarm automatically ceases.

1. Log on to the System Controller (SC).
2. Make sure that the SC is the primary processor:

   cat/proc/drdb

   The following is the expected output when the SC is the primary processor:

   0:cs:Connected st:Primary/Secondary id:Consistent

   The following is the expected output when the SC is the secondary processor:

   0:cs:Connected st:Secondary/Primary id:Consistent

3. Check the log file for error 3xxx (protocols errors):

   grep “Result-Code= [30” /storage/no-backup/cdclsv/log/lpmsv/*

4. Log off from the SC.
5. Make sure that the alarm is matching with the errors in the log.
6. Find the cause why the HSS is busy.
7. Is the alarm threshold is set too low?

   Yes: Adjust the alarm threshold and then continue with the next step.

   No: Continue with the next step.

8. Has the alarm ceased?

   Yes: Proceed with Step 10.

   No: Continue with the next step.

9. If the alarm is not ceased, consult the next level of maintenance support.

   Further actions are outside the scope of this instruction.

10. Job is completed.