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2.6.124 LOS (STMN)
2.6.124 LOS (STMN)
A Loss of Signal Line alarm for either an STM-16 or STM-64 port occurs when the port on the card is
in service but no signal is being received. The cabling might not be correctly connected to the ports, or
no signal exists on the line. Possible causes for a loss of signal include upstream equipment failure or a
fiber cut. It clears when two consecutive valid frames are received.
Clear the LOS (STMN) Alarm
Verify fiber continuity to the port. To verify cable continuity, follow site practices.
Step 1
Always use the supplied electrostatic discharge wristband when working with a powered
Caution
ONS 15600 SDH. Plug the wristband cable into the ESD jack located on the lower-right edge of the shelf
assembly.
If the cabling is good, verify that the correct port is in service by completing the following steps:
Step 2
a.
b.
c.
d.
e.
f.
Step 3
If the correct port is in service, 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 15600 SDH Procedure
Guide.
If the alarm does not clear, verify that the power level of the optical signal is within the STM-N card
Step 4
receiver specifications. The
page 1-74
If the optical power level is within specifications, use an optical test set to verify that a valid signal exists
Step 5
on the line. For specific procedures to use the test set equipment, consult the manufacturer. Test the line
as close to the receiving card as possible.
Step 6
If a valid signal exists, replace the connector on the backplane.
Repeat Steps
Step 7
Cisco ONS 15600 SDH Troubleshooting Guide, R8.0
2-86
Default Severity: Critical (CR), Service-Affecting (SA)
Logical Object: STMN
Confirm that the LED is correctly illuminated on the physical card.
A green SRV LED indicates an active card.
To determine whether the STM-N port is in service, double-click the card in CTC to display the card
view by completing the following steps:
Click the Provisioning > Line tabs.
Verify that the Admin State column lists the port as Locked.
If the Admin State column lists the port as Locked,maintenance or Locked,disabled, click the
column and choose Locked.
Click Apply.
If ports managed into Unlocked administrative state are not receiving signals, the LOS alarm
Note
is either raised or remains, and the port service state transitions to Unlocked-disabled,failed.
"1.9.3 Optical Traffic Card Transmit and Receive Levels" section on
lists these specifications for each STM-N card.
1
to
6
for any other port on the card reporting the LOS (STM-N).
Chapter 2 Alarm Troubleshooting
July 2010
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