Forward Error Correction
In DWDM spans, FEC reduces the quantities of retiming, reshaping, and regeneration (3R) needed to maintain
signal quality. The following two PM parameters are associated with FEC:
• BIT-EC: Bit errors corrected (BIT-EC ) indicates the number of bit errors corrected in the DWDM trunk
line during the PM time interval.
• UNC-WORDSThe number of uncorrectable words detected in the DWDM trunk line during the PM
time interval.
Complete the following procedure to provision BIT-EC and UNC-WORDS PM parameters for FEC.
Provision Card FEC Thresholds
SUMMARY STEPS
1.
In node view (single-shelf mode) or shelf view (multishelf mode), double-click a transponder, muxponder,
or xponder card to open the card view.
2.
Click the
Provisioning > OTN > FEC Thresholds
tabs.
3.
In the Bit Errors Corrected field, enter a threshold number, for example 225837.
4.
In the Uncorrectable Words field, enter a threshold number, for example, 2.
5.
In the Intervals area, click
15 Min
.
DETAILED STEPS
Step 1
In node view (single-shelf mode) or shelf view (multishelf mode), double-click a transponder, muxponder, or xponder
card to open the card view.
Step 2
Click the
Provisioning > OTN > FEC Thresholds
tabs.
Step 3
In the Bit Errors Corrected field, enter a threshold number, for example 225837.
Step 4
In the Uncorrectable Words field, enter a threshold number, for example, 2.
Step 5
In the Intervals area, click
15 Min
.
Sample Trouble Resolutions
The following sample trouble resolutions use PM and TCAs to isolate degrade points.
Problem
There is a BBE TCA on a single transponder pair.
Possible Cause
The transponder input power is out of range.
Solution
Check the input power on the transponder. It should be within the specified/supported range.
Possible Cause
There are dirty trunk connectors on the transponder.
Solution
Check the connector on the trunk port.
Possible Cause
There is a degraded trunk patchcord between the transponder and the DWDM port.
Solution
Check the patchcord on the transponder DWDM port.
Cisco NCS 2000 series Troubleshooting Guide, Release 11.0
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General Troubleshooting
Forward Error Correction