Cisco ONS 15454 DWDM - Page 100

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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
Figure 1-36 Optical Drop Power More than 6 dB Lower than Expected
1.13.2.3.2 Condition C2—Delta Power < 6 dB Lower than Expected
If the delta power is less than 6 dB lower than expected, the final conditions reported in CTC are the
same as those reported for Condition B2 (see the “1.13.2.2.2 Condition B2—Delta Power < 6 dB
(OPWR-LowDEGrade Alarm)” section on page 1-92):
• Αn OPWR-LowDEGrade (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
CTC Power field, but the value is (VOA Power Ref – 6 dBm) < Power < VOA Power Ref
(Figure 1-35). To view this value in card view, click the Provisioning > Parameters tabs.
A dirty connection or excessive loss of the incoming span are among the possible reasons that can lead
to a fault condition. They are the most common and affect all wavelengths, whereas an excessive
amplifier gain tilt or a wavelength misconfiguration on the far-end TXP or MXP card can lead to
condition where only a single wavelength fails, such as the one (Channel 25) shown in Figure 1-37.