Cisco ONS 15310-MA Troubleshooting Manual page 98

Alarm Procedures
If there is a valid signal, clean the fiber according to site practice. If no site practice exists, complete the
Step 3
procedure in the "Maintain the Node" chapter in the Cisco ONS15310-MA SDH Procedure Guide.
Step 4 If the alarm does not clear, verify that the UDC is provisioned by completing the following steps:
a.
b.
c.
Step 5 If the alarm does not clear, look for and troubleshoot any other alarm that could identify the source of
the problem.
If the alarm does not clear, log into the Technical Support Website at
Step 6
http://www.cisco.com/cisco/web/support/index.html for more information or call Cisco TAC
(1-800-553-2447).
2.7.138 LOS (STM)
An LOS alarm on an STM1 or STM4 port occurs when a SDH receiver detects an all-zero pattern for
10 microseconds or longer. An LOS alarm means the upstream transmitter has failed. If an STM1 or
STM4 LOS alarm is not accompanied by additional alarms, a fiber break is usually the cause of the
alarm. It clears when two consecutive valid frames are received.
Invisible laser radiation could be emitted from the end of the unterminated fiber cable or connector.
Warning
Do not stare into the beam directly with optical instruments. Viewing the laser output with certain
optical instruments (for example, eye loupes, magnifiers, and microscopes) within a distance of
100 mm could pose an eye hazard. Statement 1056
Use of controls, adjustments, or performing procedures other than those specified could result in
Warning
hazardous radiation exposure. Statement 1057
If a circuit shows a partial status when this alarm is raised, the logical circuit is in place. The circuit is
Note
able to carry traffic when the connection issue is resolved. You do not need to delete the circuit when
troubleshooting this alarm.
Clear the LOS (STM) Alarm
Using site practices, verify fiber continuity to the port.
Step 1
Cisco ONS 15310-MA SDH Troubleshooting Guide, Release 9.0
2-98
At the network view, click the Provisioning > Overhead Circuits tabs.
If no UDC circuit exists, create one. Refer to the "Create Circuits" chapter in the
Cisco ONS15310-MA SDH Procedure Guide for procedures.
If a user data circuit exists (shown as User Data F1 under the Type column), check the source and
destination ports.
Default Severity: Critical (CR), Service-Affecting (SA)
SDH Logical Object: STM
Chapter 2 Alarm Troubleshooting
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