Contents

1   Introduction

This instruction concerns alarm handling.

1.1   Alarm Description

This threshold alarm CSCF SIP Request Timed Out indicates that there is a communication failure to a SIP server.

The alarm is associated to the Performance Management counter sipStatsReqTimeout. The counter sipStatsReqTimeout is stepped every time a SIP request times out without having received a response.

The alarm is raised when the number of sipStatsReqTimeouts 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=151, and thresholdLow=3. This means that when the counter value is 151 or higher, the alarm is raised when the granularity period is ended. The alarm is ceased when the counter sipStatsReqTimeout has reached a value of 3 at the end of a granularity period.

Note:  

The thresholds for raising and ceasing this alarm are configurable. The default distinguished name for the thresholds is ManagedElement=<node_name>, SystemFunctions=1, Pm=1, PmJob=CscfSipClientThreshold,MeasurementReader=sipStatsReqTimeoutMeasReader, PmThresholdMonitoring=sipStatsReqTimeout.

It is not possible to change threshold values 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.

The possible alarm causes and the corresponding fault reasons, fault locations, and impacts are described in Table 1.

Table 1    Alarm Causes

Alarm Cause	Description	Fault Reason	Fault Location	Impact
The PM counter sipStatsReqTimeout has reached or exceeded its configured upper threshold value.	The number of received SIP communication failure errors has reached or exceeded the configured threshold.	Peer entity communication problems (SIP Request time out) to manage SIP messages.	Peer protocol communication problems between SIP servers.	Connection problems on CSCF SIP traffic interfaces causing communication issues with destination SIP servers.

Note:  

An alarm can appear as a result of maintenance activity.

The alarm attributes are listed and explained in Table 2.

Table 2    Alarm Attributes

Attribute Name	Attribute Value
Major Type	193
Minor Type	6684689
Managed Object Class	MeasurementReader
Managed Object Instance	ManagedElement=<node_name>,SystemFunctions=1, Pm=1, PmJob=CscfSipClientThreshold,MeasurementReader=sipStatsReqTimeoutMeasReader
Specific Problem	CSCF SIP Request Timed Out
Event Type	communication (2)
Probable Cause	x733CommunicationsProtocolError (305)
Additional Text	-
Perceived Severity	minor (5)

1.2   Prerequisites

This section provides information on the documents, tools, and conditions that apply to the procedure.

1.2.1   Documents

This instruction references the following document:

• Performance Management
• Managed Object Model (MOM)

1.2.2   Tools

No tools are required.

1.2.3   Conditions

No conditions.

2   Procedure

Note:  

If the reason for the alarm has disappeared after the granularity period, the alarm automatically ceases.

Do the following:

1. Check the details of the issued alarm to get the affected subsystems and the detailed specific cause.

   It is possible to get the sipStatsReqTimeout counter keyed on specific IP addresses. To achieve this, configure the suspected IP addresses into the configuration parameter cscfSipPMKey. This tells the amount of transaction time-out per configured IP address.

   It is also possible to get additional information by enabling the function "monitoring" by setting cscfMonitorEnabled = true. Because of transaction time-out for the blacklisted destinations, the alarm CSCF, SIP Monitored Interface Unreachable is raised. Information about source and destination transport addresses is then provided.

2. Detect and eliminate any connection problems on the CSCF SIP traffic interfaces, if possible.
3. The alarm is ceased when the communication with the destination is working.
4. The alarm depends on the neighboring SIP nodes and transport network, so both the thresholds for raising and ceasing the alarm may have to be adjusted to suit the specific IMS network.
5. Confirm that the alarm has ceased. If the alarm remains, consult the next level of maintenance support. Further actions are outside the scope of this instruction.
6. Job is completed.