Clear The Los (Trunk) Alarm - Cisco NCS 2000 series Troubleshooting Manual

Alarm Troubleshooting
Note The MXP_2.5G_10E card has no LOS (TRUNK) option, because G.709 cannot be disabled on the card.
The alarm is raised when the card port is not receiving input. An AIS is sent upstream.
The purpose of the LOS (TRUNK) alarm is to alert the user that no optical power is being received from the
fiber. A typical fault condition signalled by the LOS (TRUNK) alarm is a fiber cut. In this case, neither the
payload nor the overhead signals are being received.
Note With G.709 off, the alarm coming from the trunk is LOS (TRUNK) in accordance with SONET standards.
Note
In R7.01, when an LOS (TRUNK) alarm occurs on TXP and MXP trunks, G709/SONET/SDH TCAs are
suppressed.

Clear the LOS (TRUNK) Alarm

Check the PMs of the TRUNK-RX port and verify that the received power is above the optics threshold.
SUMMARY STEPS
1. Check that a proper threshold has been provisioned. (For procedures, refer to the Provision Transponder
and Muxponder Cards chapter in the Configuration guide.) If an incorrect threshold has been set, adjust
it to a value within the allowed limits. If the alarm condition does not clear, move to next step.
2.
3. Using an optical test set, verify that a valid signal exists on the line and feeds the TRUNK-RX port.(For
specific procedures to use the test set equipment, consult the manufacturer.) Test the line as close to the
receiving card as possible. If the alarm condition does not clear, move to next step.
4. Verify whether a bulk attenuator is specified in the Cisco TransportPlanner design. If so, verify that the
proper fixed attenuation value has been used.
5.
6. Look for and troubleshoot any alarms reported by the DWDM cards belonging to the OCHNC circuit
whose destination is the faulty TXP/MXP. Possible alarms include: amplifier gain alarms (the
, on page 208
GAIN-LFAIL , on page 211
APC-OUT-OF-RANGE , on page 120
the OCHNC circuit.
DETAILED STEPS
Step 1 Check that a proper threshold has been provisioned. (For procedures, refer to the Provision Transponder and Muxponder
Cards chapter in the Configuration guide.) If an incorrect threshold has been set, adjust it to a value within the allowed
limits. If the alarm condition does not clear, move to next step.
Step 2
alarm, the GAIN-HFAIL , on page 210
alarm); APC alarms (the
alarm), OR LOS-P alarms on the Add or Drop ports belonging to
Cisco NCS 2000 series Troubleshooting Guide, Release 11.0
Clear the LOS (TRUNK) Alarm
alarm, the GAIN-LDEG , on page 211
APC-CORR-SKIPPED , on page 119
GAIN-HDEG
alarm or
alarm and
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