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OSN 500 550 580 V100R008C50 Alarms and Performance Events Reference 02

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ODUk TCMn signal being degraded. This alarm is generated if signal degradation occurs or the bit error count exceeds the threshold when the error detection is in burst mode.

  • k indicates the level of rate, its value is 0, 1, or 2.
  • n indicates the level of TCM, its value ranges from 1 to 6.


Alarm Severity Alarm Type


Communication alarm



Impact on the System

If the alarm is generated, the services at the optical interface generate bit errors, which make the service signals unavailable.

Possible Causes

  • The optical interface that reports the alarm is faulty.

  • The optical interface at the peer end is faulty.

  • The fiber of the transmission line is abnormal.


  1. On the NMS, browse alarms of the entire network to determine the slot ID, interface ID, and channel ID of the board that generates this alarm.
  2. Locate the point that first generates the ODUk_TCMn_DEG alarm according to the service route.
  3. Check whether the input optical power of the place where the alarm is first generated is within the permitted range on the NMS. If it is not, handle the alarm according to the handling procedures of the IN_PWR_HIGH and IN_PWR_LOW alarms.
  4. If the alarm persists, check whether the fiber meets the following requirements:

    • The bending radius is not less than 6 cm.
    • The optical interface connector is well inserted.
    • The fiber connector is clean.
    • The cable is intact.

    If the preceding requirements are not met, clean the fiber connector or replace the fiber. For details, see Cleaning the Optical Fiber Connector.

  5. If the alarm persists, the optical interface on the board at the local end may be faulty. Replace the pluggable optical module or the faulty board.
  6. If the alarm persists, the optical interface on the universal line board at the peer end may be faulty. Replace the pluggable optical module on the board or the faulty OTU board.
  7. Check whether the alarm is cleared. If the alarm persists, contact Huawei engineers to handle the alarm.

Related Information


Updated: 2019-01-21

Document ID: EDOC1100020975

Views: 76023

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