Specifications
1-3
Cisco ONS 15454 Troubleshooting and Maintenance Guide
November 2001
Chapter 1 Alarm Troubleshooting
1.2 Trouble Notifications
The ONS 15454 uses standard Telcordia categories to characterize levels of trouble. The ONS 15454
reports both alarmed trouble notifications, under the Alarms tab, and non-alarmed (NA) trouble
notifications, under the Conditions tab in CTC. Alarms signify a problem that the user needs to fix, such
as a loss of signal (LOS). Conditions notify the user of an event which does not require action, such as
a switch to a secondary timing reference (SWTOSEC) or a user-initiated manual reset (MANRESET).
Telcordia further divides alarms into Service-Affecting (SA) and Non-Service-Affecting (NSA) status.
An
SA failure affects a provided service or the network’s ability to provide service. For example, a
missing transmitter (TRM-MISS) alarm is characterized as an SA failure. TRM-MISS occurs when the
cable connector leading to a port on an active DS1-14 card is removed. This affects a provided service,
because traffic switches to the protect card. The high temperature (HITEMP) alarm, which means the
ONS 15454 is hotter than 122 degrees Fahrenheit (50 degrees Celsius), is also an SA failure. Although
for example a particular DS-1 port may not be affected, a high temperature affects the network’s ability
to provide service.
1.2.1 Conditions
When an SA failure is detected, the ONS 15454 also sends an alarm indication signal (AIS) downstream.
When it receives the AIS, the receiving node sends a remote failure indication (RFI) upstream. AIS and
RFI belong in the conditions category and show up on the Conditions screen of the ONS 15454.
However, unlike most conditions which are non-alarmed, Telcordia classifies these conditions as not
reported (NR).
Both CTC and TL1 report NRs and NAs as conditions when conditions are retrieved. NAs are also
reported as autonomous events under TL1 and under the History tab of the CTC. For a comprehensive
list of all conditions, see the Cisco ONS 15454 TL1 Command Guide.
1.2.2 Severities
The ONS 15454 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 a DS-1 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 affect on service.
FSTSYNC lets you know that the ONS 15454 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 disrupt service.
Telcordia standard severities are the default settings for the ONS 15454. A user may customize ONS
15454 alarm severities with the alarm profiles feature. For a description of alarm profiles, see the Cisco
ONS 15454 Installation and Operations Guide.
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, Non-Service-Affecting.