Link Flap

Description

This violation is triggered when more than 10 Link-Up/Link-Downs occur within a minute or when a 30 Link-Up/Link-Downs occur within 5 minutes. The Link-Flap alarm is raised when both the Port Profile "Link Flap Violation" is enabled and the NAC Profile "Access Violation Auto  Disable" is enabled and, when alarmed, the port is disabled for the duration of the NAC Profile "Auto Enable Delay."

Trouble Clearing

• Cable connector poorly seated: Remove and re-insert the cable at both ends ensuring it is properly seated and clicks.
• Bad Ethernet Port at ONT UNI port or attached equipment
  • Test ONT UNI: Moving the cable to a different ONT UNI port with the same configuration, if the Link flap issue goes away, it was likely the ONT port. Move to a different port or replace the ONT.
  • Test Attached Device: If possible, swap the attached device with a known good device that does not exhibit link flap issues.  If that clears up the issue, replace the ONT. 
• Bad Ethernet Cabling: A very common cause for this alarm is poorly terminated connectors, or bad cabling.
   

  Laser Safety

  Warning! Personnel handling fiber optic cables must be trained for laser safety.

  Warning! Optical Fibers emit invisible laser radiation. Avoid direct exposure to the beam. Never look into the end of a Fiber or into a Fiber connector on a cable or a device. Permanent eye damage or blindness can occur quickly from laser radiation.

   
  • Perform Cable Test: Attach a cable tester to both ends of the cable and ensure the cable tests as good and passes all performance metrics.
    • Re-terminate Cable: If the cable fails the cable test, re-terminate the cable as many issues are poorly terminated cables, cables that have over time begun to have issues with their connectors.
    • Wrong Cable for 10G: 10G cables have higher requirement for bandpass and should be a Cat6a or above.
      • CAT6a or above cable was terminated with a Cat5 connector.
      • CAT6a or above cable length exceeds 100m
    •  Replace Cable: If re-terminating the cable does not resolve the problem, replace the cable.
       

      Note: It is not uncommon to see poorly terminated cables on new installs, ensuring that all cables are tested during the installation process and a test report provided for all install cables can help minimize issues needing to be resolved during installation.