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OSN 500 550 580 V100R008C50 Alarms and Performance Events Reference 02

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Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).



The ALM_ALS alarm indicates that the laser on a line board is in the auto laser shutdown (ALS) state.

If the ALM_ALS alarm is generated, the R_LOS alarm has been generated at the optical port of the line board. To prevent damage to the laser, the laser enters the ALS state. After the R_LOS alarm is cleared, the laser automatically exits the ALS state.


Alarm Severity Alarm Type


Equipment alarm



Impact on the System

The ALM_ALS alarm does not have any impact on the system.

Possible Causes

The possible cause of this alarm is as follows:

The ALS function is enabled for the optical port, and the R_LOS alarm is generated at the optical port. As a result, the laser enters the ALS state and reports the ALM_ALS alarm.


  1. Check whether the line board reports the R_LOS alarm. If the line board reports the R_LOS alarm, clear the alarm. Then, check whether the ALM_ALS alarm is cleared.

    If... Then...
    The alarm is cleared No further action is required.
    The alarm persists Go to the next step.

  2. Disable the ALS function for the optical port on the line board. Then, check whether the ALM_AIS alarm is cleared.

    If... Then...
    The alarm is cleared No further action is required.
    The alarm persists Contact Huawei technical support engineers to handle the alarm.

Related Information

Updated: 2019-01-21

Document ID: EDOC1100020975

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