Severities; Alarm Procedures; Ais; Ais-L - Cisco ONS 15327 User Documentation

Chapter 14 Alarm Troubleshooting

14.3.2 Severities

The ONS 15327 uses Tecordia-standard severities: Critical (CR), Major (MJ), and Minor (MN). Critical
indicates a severe, service-affecting alarm that needs immediate correction. Major is still a serious alarm,
but the failure has less of an impact on the network. For example, with an XTC LOS, a Major alarm, 24
DS-0 circuits lose protection. But with a OC-192 LOS, a Critical alarm, over a hundred thousand DS-0
circuits lose protection.
Minor alarms, such as Fast Start Synchronization (FSTSYNC), do not have a serious effect on service.
FSTSYNC lets you know that the ONS 15327 is choosing a new timing reference because the old
reference failed. The loss of the prior timing source is something a user needs to look at, but it should
not immediately disrupt service.
Telcordia standard severities are the default settings for the ONS 15327. A user may customize ONS
15327 alarm severities with the alarm profiles feature. For a description of alarm profiles, see
Chapter 10, "Alarm Monitoring and
This chapter lists the default alarm severity for the active reporting card, if applicable. The default
severity for alarms reported by standby cards is always Minor, NSA.

14.4 Alarm Procedures

This section list alarms alphabetically and includes some conditions commonly encountered when
troubleshooting alarms. The severity, the description and the troubleshooting procedure accompany each
alarm and condition.

14.4.1 AIS

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The ONS 15327 detects an AIS in the SONET overhead. This alarm is secondary to another alarm
occurring simultaneously in an upstream node. An incomplete circuit path causes an AIS. For example,
this alarm occurs when the port on the reporting node is in service but the OC-N port on a node upstream
on the circuit is not in service. The upstream node often reports a loss of service or has an out-of-service
port. The AIS clears when you clear the primary alarm on the upstream node. However, the primary
alarm node may not report any alarms that indicate it is at fault.
Procedure: Clear the AIS Condition
Check upstream nodes and equipment for alarms, especially for LOS and out-of-service ports.
Step 1
Clear the upstream alarms.
Step 2

14.4.2 AIS-L

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June 2002
Not Reported (NR)
Not Reported (NR)
Management".
Cisco ONS 15327 User Documentation, R3.3
Alarm Procedures
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