Cisco NCS 2000 series Troubleshooting Manual page 115

General Troubleshooting
Figure 15: Network View for Span Loss Change > 5 dBm and OSC Power Value at Receiver > –42 dBm
In node view (single-shelf mode) or shelf view (multishelf mode), the EOC condition is cleared, but the alarm
panels of the two nodes (ROADM and OLA in the example) continue to show LOS (OTS or AOTS) on the
LINE-RX port of the OPT-BST, OPT-AMP-C, OPT-AMP-17-C, or OSC-CSM.
The network ALS protocol keeps the OCHNC traffic down along the span because the new losses of the
restored span can potentially affect the optical validation of the network design done by Cisco TransportPlanner.
Corrective Action for Scenario 2
SUMMARY STEPS
1.
2.
3.
4.
5.
6.
7.
8.
Verify the validity of the alarm.
For both DWDM nodes connected to the repaired span:
Measure the new Span Loss value after fixing the fiber.
Compare the span measurements of Step 3 with the span losses values used during the network design
with Cisco TransportPlanner.
For the two fibers belonging to the repaired span, identify the fiber for the W–E line direction and
calculate the insertion loss variation. If the span loss change is greater than 3 dBm, continue with Step
6. If not, go to Step 9.
Clean the LINE-RX and LINE-TX connectors on the DWDM cards managing the fiber of the repaired
span. If the problem persists, continue with Step 7.
If the alarm condition is still reported, it is recommended that the fiber be repaired again to reestablish
the expected span loss value. If this is not possible and the new value of span loss cannot be modified,
go to Step 8 to fix the system faulty condition.
Follow the signal flow into the network starting from the repaired fiber:
Cisco NCS 2000 series Troubleshooting Guide, Release 11.0
Corrective Action for Scenario 2
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