Cisco ONS 15454 - 2.7.224 LOS (ISC); 2.7.225 LOS (MSUDC); 2.7.226 LOS (OCN)

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Cisco ONS 15454 Troubleshooting Guide, R8.5
November 2009
Chapter 2 Alarm Troubleshooting
2.7.224 LOS (ISC)
Step 2 Verify that there is a valid input signal using a test set. For specific procedures to use the test set
equipment, consult the manufacturer.
Step 3 If there is a valid signal, clean the fiber according to site practice. If no site practice exists, complete the
procedure in the “Maintain the Node” chapter in the Cisco ONS 15454 Procedure Guide.
Step 4 If the alarm does not clear, verify that the UDC is provisioned:
a. At the network view, click the Provisioning > Overhead Circuits tabs.
b. If no UDC circuit exists, create one. Refer to the “Create Circuits and VT Tunnels” chapter in the
Cisco ONS 15454 Procedure Guide.
c. If a user data circuit exists (shown as User Data F1 under the Type column), check the source and
destination ports. These must be located on AIC-I cards to function.
Step 5 If the alarm does not clear, look for and troubleshoot any other alarm that could identify the source of
the problem.
Step 6 If no other alarms exist that could be the source of the LOS (FUDC), or if clearing another alarm did not
clear the LOS, complete the “Physically Replace a Traffic Card” procedure on page 2-273 for the
reporting card.
Step 7 If the alarm does not clear, log into the Technical Support Website at http://www.cisco.com/techsupport
for more information or call Cisco TAC 1 800 553-2447.
2.7.224 LOS (ISC)
For information about this alarm or condition, refer to the “Alarm Troubleshooting” chapter in the
Cisco ONS 15454 DWDM Troubleshooting Guide. This guide discusses all DWDM alarms.
2.7.225 LOS (MSUDC)
The LOS (MSUDC) alarm is not used in this platform in this release. It is reserved for future
development.
2.7.226 LOS (OCN)
Default Severity: Critical (CR), Service-Affecting (SA)
SONET Logical Object: OCN
An LOS alarm on an OC-N port occurs when a SONET receiver detects an all-zero pattern for
10 microseconds or longer. An LOS alarm means the upstream transmitter has failed. If an OC-N 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.
Warning On the OC-192 card, the laser is on when the card is booted and the safety key is in the on position
(labeled 1). The port does not have to be in service for the laser to be on. The laser is off when the
safety key is off (labeled 0). Statement 293