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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
Note X is number (1 to 4) of the proper multifiber MPO connector that manages the alarmed
channel (wavelength).
• The Power field value must be the same as that in the VOA Power Ref field. If it is not, take the
appropriate corrective action for the alarm according to Chapter 2, “Alarm Troubleshooting.”
c. Check (the number [1 to 8] must correspond with the wavelength managed) and clean the LC fan-out
according to site practice.
d. Repeat Step c for the MPO-LC multifiber cable coming out of the DROP_TX port of the coupled
32DMX-O card.
e. Check and, if necessary, clean the LC-LC adapter used.
f. If necessary, replace any bad devices (maximum tolerance is 1 dB).
Note If no site practice exists for cleaning fibers, complete the procedure in the “Maintain the
Node.” chapter of the Cisco ONS 15454 DWDM Procedure Guide.
Note If the alarm condition persists even after the cable check and repair procedures, the root cause
could be related to a network issue and a more accurate analysis of the signal flow is needed
according with the actual system topology. If necessary, call Cisco TAC (1 800 553-2447) for
help.
1.13.2.3 Scenario C: Optical Drop Power Level Lower Than Expected
This scenario describes the condition in which the optical power at the 32DMX-O drop channels is lower
than expected. The 32DMX-O card is equipped with a VOA for each wavelength, and each VOA
manages the power for one dropped wavelength.
The failing scenarios during the OCHNC turn-up and consequent VOA startup are the same as those
described in the “1.13.2.2 Scenario B: Optical Power Level of the Incoming Signal Lower Than
Expected” section on page 1-91. The only difference is the type of alarm that is raised when the
condition exists in which Delta Power is greater than 6 dB.
1.13.2.3.1 Condition C1—Delta Power > 6 dB Lower than Expected
When the optical power on the dropped channel is more than 6 dB lower that the value expected, the final
VOA Power Reference setpoint value is definitively not reachable. As a consequence, the final
conditions reported in CTC are as follows:
• An OPWR-LFAIL (OCH layer) alarm is present on the port associated with the VOA (see
Figure 1-36).
• A valid optical power value (different from the end of scale value of –50 dBm) can be read in the
CTC Power field, but the Power value is less than –33 dBm. (To view this value in card view, click
the Provisioning > Parameters tabs.)
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