After the OptiX OSN6800 is upgraded from version 5.51.04.13 to version 5.51.05.35, the TN11OAU101 board in slot 2 reports the VOA_ADJUST_FAIL alarm, though no other operation is performed on the OptiX OSN6800.
1. OAU boards must be configured with nominal gains before being used. You can run the cfg-set-stdgain command to set the nominal gain for an OAU board. The total gain of the PA and BA boards is fixed. You can adjust the board gain by modifying the intermediate insertion loss. The intermediate insertion loss involves the attenuation of the VOA integrated to the OAU board and the DCM insertion loss between the TDC and RDC optical interfaces. If the insertion loss between the TDC and RDC optical interfaces exceeds the maximum value, the nominal gain cannot be a large value and the gain spectrum of the board deteriorates.
Maximum allowable gain = Maximum gain � VOA attenuation - Intermediate insertion loss between the TDC and RDC optical interfaces
Software computes and automatically adjusts VOA attenuation. Therefore, users do not need to manually adjust it. The minimum value of the VOA attenuation is 0 dB.
Note: The VOA attenuation queried through the GUI or CLI is the total attenuation. Total attenuation = Fixed insertion loss + VOA attenuation
2. Run the following commands to obtain the maximum allowable gain after the OAU board is connected to the DCM.
Run the following command to obtain the range of the actual allowable gain after the OAU board is connected to the DCM:
Run the following command to obtain the range of the nominal gain of the OAU board (only when the TDC and RDC optical interfaces are short-circuited):
Run the following command to obtain the current nominal gain of the OAU board:
If the nominal gain of the board exceeds the maximum allowable gain after the OAU board is connected to the DCM, the OAU board reports the VOA_ADJUST_FAIL alarm.
1. The VOA_ADJUST_FAIL alarm is reported only after the OptiX OSN6800 is upgraded to V100R004C04SPC800. This is why the VOA_ADJUST_FAIL alarm is not reported previously.
2. Perform the following operation to clear the VOA_ADJUST_FAIL alarm.
To ensure consistent output power, increase the input optical power and set the gain to a value within the allowable gain range.
For details about troubleshooting, see the following attachment.
The VOA_ADJUST_FAIL alarm indicates that the attenuation of the variable optical attenuator (VOA) fails to be adjusted. There are two reasons for the failure.
Reason 1: The gain of the OAU board exceeds the maximum allowable value.
Reason 2: The VOA of the OAU board is faulty and cannot be adjusted.
Note changes of alarms before and after the upgrade. Contact Huawei technical support engineers in time when abnormal alarms occur.