No relevant resource is found in the selected language.

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies. Read our privacy policy>Search


To have a better experience, please upgrade your IE browser.


OSN 500 550 580 V100R008C50 Alarms and Performance Events Reference 02

Rate and give feedback :
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 TU_LOP alarm indicates TU pointer loss. This alarm occurs if a board detects that the TU-PTR value is an invalid pointer or NDF reversion in eight consecutive frames.


Alarm Severity Alarm Type


Communication alarm



Impact on the System

The TU_LOP alarm causes service interruptions in the TU path of the relevant board. If the service is configured with protection, the protection switching is also triggered.

Possible Causes

Possible causes of the TU_LOP alarm are as follows:

  • Service cross-connections are incorrectly configured.
  • The system control, cross-connect, and timing board is faulty.
  • The board is faulty.


  1. Check whether the cross-connect service configuration is consistent with the plan. If the configuration is inconsistent with the plan, re-configure the cross-connect service as planned. If the configuration is consistent with the plan, go to 2.
  2. Check whether the system control and cross-connect board is faulty. If the board is faulty, replace it. If the board is working properly, go to 3.
  3. Check whether any board on the local or peer NE is faulty by performing loopbacks. If any board is found faulty, replace it. If the TU_LOP alarm persists, contact Huawei technical support engineers to handle the alarm.

Related Information


Updated: 2019-01-21

Document ID: EDOC1100020975

Views: 75145

Downloads: 138

Average rating:
This Document Applies to these Products
Related Documents
Related Version
Previous Next