Cisco ONS 15454 - 2.5.4 Alarm Hierarchy

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Cisco ONS 15454 Troubleshooting Guide, R8.5
November 2009
Chapter 2 Alarm Troubleshooting
2.5.4 Alarm Hierarchy
2.5.4 Alarm Hierarchy
All alarm, condition, and unreported event severities listed in this manual are default profile settings.
However in situations when traffic is not lost, such as when the alarm occurs on protected ports or
circuits, alarms having Critical (CR) or Major (MJ) default severities can be demoted to lower severities
such as Minor (MN) or Non-Service-Affecting (NSA) as defined in Telcordia GR-474-CORE.
A path alarm can be demoted if a higher-ranking alarm is raised for the same object. For example, If a
path trace identifier mismatch (TIM-P) is raised on a circuit path and then a loss of pointer on the path
(LOP-P) is raised on the path, the LOP-P alarm stands and the TIM-P closes. The path alarm hierarchy
used in the ONS 15454 system is shown in Table 2-9.
Facility (port) alarms also follow a hierarchy, which means that lower-ranking alarms are closed by
higher-ranking alarms. The facility alarm hierarchy used in the ONS 15454 is shown in Table 2-10.
Near-end failures and far-end failures follow different hierarchies. Near-end failures stand according to
whether they are for the entire signal (LOS, LOF), facility (AIS-L), path (AIS-P, etc.) or VT (AIS-V,
etc.). The full hierarchy for near-end failures is shown in Table 2-11. This table is taken from
Telcordia GR-253-CORE.
Table 2-9 Path Alarm Hierarchy
Priority Condition Type
Highest AIS-P
—LOP-P
—UNEQ-P
Lowest TIM-P
Table 2-10 Facility Alarm Hierarchy
Priority Condition Type
Highest LOS
—LOF
—AIS-L
—SF-L
—SD-L
—RFI-L
—TIM-S
—AIS-P
—LOP-P
—SF-P
—SD-P
—UNEQ-P
—TIM-P
Lowest PLM-P