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Cisco ONS 15454 DWDM Troubleshooting Guide, R7.0.1
78-17742-02
Chapter 1 General Troubleshooting
1.13.2 VOA Failure Scenarios
• Click Apply. If the LOS-P alarm persists, continue with this procedure. Otherwise, the problem
has been corrected.
e. Click Circuits.
f. Recreate the OCHNC circuit and verify that Circuit Status field reports DISCOVERED and the state
is IS (Unlocked).
g. If the LOS-P alarm has not cleared, replace the 32MUX-O card (refer to the “Add and Remove Cards
and Nodes” chapter of the Cisco ONS 15454 DWDM Procedure Guide). Before you replace the card,
log into the Technical Support Website at http://www.cisco.com/techsupport for more information
or call Cisco TAC (1 800 553-2447) in order to report a service-affecting problem).
Warning
High-performance devices on this card can get hot during operation. To remove the card, hold it by
the faceplate and bottom edge. Allow the card to cool before touching any other part of it or before
placing it in an antistatic bag.
Statement 201
1.13.2.2 Scenario B: Optical Power Level of the Incoming Signal Lower Than Expected
In some cases, the pass-through channels on the 32WSS card or the optical bypass channels on the
32MUX-O card are at a power level that is lower than expected. The incoming power level can be lower
than expected for several reasons. A few examples are:
• Dirty connections
• Excessive span loss
• Wrong amplifier gain setting
When the power is lower than expected, the start-up procedure can stop at Phase 1, Phase 2, or Phase 3
(see Figure 1-32). The point at which the start-up procedure stops depends on the amount of power
missing.
Given that Delta Power is the amount of optical power missing compared to the expected value, two final
conditions for Scenario B can be identified, Conditions B1 and B2.
1.13.2.2.1 Condition B1—Delta Power > 6 dB (LOS-P Alarm)
When the optical power is more than 6 dB lower than the expected value, the final VOA Power Reference
setpoint value is definitively not reachable and even Phase 1 of the start-up procedure cannot be properly
completed. As a consequence, the final condition reported in CTC is the same as that of Scenario A:
• A LOS-P (OCH layer) alarm is present on the port associated with the VOA.
• A valid optical power value (different from the end of scale value of – 50 dBm) can be read in the
Power field, but the value for Power is less than –33 dBm (see Figure 1-34). (To access this value,
in card view, click the Provisioning > Parameters tabs.)
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