VA4 Board Reports R_LOS When the Receiver Power Is Below -23 dBm Even If the Attenuation Is Decreased

The VA4 board reports the R_LOS alarm when the receiver power is below -23 dBm even if the attenuation of this VA4 board is decreased.

Product

OptiX OSN6800,OSN8800

Fault Type

Abnormal Optical Power

Variable Optical Attenuator Unit

R_LOS

Symptom

The VA4 board (SSE1VA401) reports the R_LOS when the receiver power is below -23 dBm. But this VA4 board still decreases its attenuation at this time.

Cause Analysis

The R_LOS threshold of the VA4 board is -23 dBm. Thus, the board reports the R_LOS alarm when the receiver power is lower than or equal to -23 dBm. But the board is still able to decrease its attenuation according to its working principle after the alarm is generated.

When such a problem occurs, the customer often worries that the VA4 board may fail to function normally. To check whether the VA4 board can function normally when such a problem occurs, do as follows.

Procedure

1. Query the optical power performance value (IOPCUR(dBm)) of the faulty optical interface on the VA4. Note that the value should be -60. The steps for querying the performance value is as follows:
   1. Choose Performance > Browse WDM Performance from the Main Menu. Click the Current Performance Data tab.
   2. In the Object Tree, select the VA4 board, and then click the double right arrow button.
   3. Configure Monitored Object Filter Condition, Monitor Period and Performance Event Type.
   4. Click Query to query the data on the NE.
2. Perform the following operations to query the receiver power of the board interconnected with the VA4 board:
   1. In the NE Explorer, select the target board and then choose Configuration > Optical Power Management from the Function Tree.
   2. In the Object Tree, select the VA4 board, and then click the double right arrow button.
   3. Click Query to read the current optical power value from the NE. The Operation Result dialog box is displayed, indicating that the operation is successful.
3. Adjust the attenuation of the VA4 board by 1 to 2 dB on the T2000 to check whether the VA4 board works normally. The steps are as follows:
   1. In the NE Explorer, select the desired board and then choose Configuration > WDM Interface from the Function Tree.
   2. Select By Board/Port(Channel).
   3. Select Channel from the drop-down list.
   4. Adjust the value of Attenuation Ratio (dB) on the Basic Attributes tab.

Result

The problem is solved after the examination is finished.

Reference Information

None.

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