TDC-ADJUSTENABLE function high Bit errors on NS3 card

Issue Description

8 OSN 6800 are configured for making 40G DWMD ring
NE version is 5.51.05.35 NMS version is U2000V100R001C00SPC003

Alarm Information

BEFFEC-EXC

Handling Process

Cheked the Tx and Rx power on far end and local side,but both are fine
check the powers of all pass throughs on MCA there was no such variation on pass through channels
Check the board performance ,all performances were fine
When check the dispersion parameters the TDC-ADJUSTENABLE function was disable ,when enable this function all errors were cleared

Root Cause

1. Optical power value issue: need check whether it is low or high onwhole span including all pass throughs on MCA
2. OSNR issue:  need check the link power
3. Dispersion issue: if all wavelength have the same poor FEC-BEF-BER, consider dispersion issue
4. hardware issue ,need to replace

Suggestions

Always suggested to enable TDC-ADJUSTENABLE function ,otherwise due to this the 40 G card will generate errors