1-105
Cisco ONS 15454 DWDM Troubleshooting Guide, R7.0.1
78-17742-02
Chapter 1 General Troubleshooting
1.13.3 Counter-Propagating Light Affecting Operation of 32DMX-C and 32DMX-L Cards
Warning
Invisible laser radiation may be emitted from the end of the unterminated fiber cable or connector. Do
not view directly with optical instruments. Viewing the laser output with certain optical instruments
(for example, eye loupes, magnifiers, and microscopes) within a distance of 100 mm may pose an eye
hazard.
Statement 1056
Note Before disconnecting any optical amplifier card fiber for troubleshooting, ensure that the
optical amplifier card is unplugged.
Note If no site practice exists for cleaning fibers, complete the procedure in the “Maintain the
Node” chapter in the Cisco ONS 15454 DWDM Procedure Guide.
f. If the alarm condition persists even after the cabling has been checked and fixed, the root cause
could be related to a network issue and a more accurate analysis of the signal flow is needed
according to the actual system topology. If necessary, call Cisco TAC (1 800 553-2447) in order to
report a service-affecting problem.
1.13.3 Counter-Propagating Light Affecting Operation of 32DMX-C and
32DMX-L Cards
Symptom The in-service operation of the 32DMX-C and 32DMX-L cards (with vendor ID 2049 and
2050) can be seriously affected by the counter-propagating light travelling from the drop ports of the
card towards the COM RX port. This counter-propagating light affects the internal VOA control loop of
the vendor-specific optical module of the 32DMX-C and 32DMX-L cards, leading to an increased
optical path attenuation. This is traffic affecting for all in-service channels.
Possible Cause The counter-propagating light can be inserted into the 32DMX-C or 32DMX-L card
as a result of incorrect cabling of transponder or line cards to the fiber patch-panel (in particular,
swapping RX with TX patchcords).
Recommended Action For software releases higher than or equal to 8.5.1, the vendor-specific optical
module on all the cards is automatically upgraded to a newer version. The vendor ID of the new
version of the card is 2051 and can be viewed at CTC > Card View > Inventory tab. This new
version of the optical module makes the VOA control robust to counter-propagating light, thus,
minimizing the effects of incorrect cabling during installation and/or maintenance.
For software releases lower than 8.5.1, for new 32DMX-C and 32DMX-L cards that are not already
installed, the vendor-specific optical module on all these new cards is automatically upgraded to a
newer version at the Cisco Spare depots. Once the new card is installed in field, a downgrade of the
optical module will be prevented and the latest optical module version is preserved on the software
package. If the 32DMX-C or 32DMX-L card is already installed, complete the “Corrective
Action—Software Releases Lower than 8.5.1” procedure on page 1-106 to manually fix the
problem.
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