• When inserting 10G SFP to EX4600 device, the interface or protocols might flap, resulting in outages.
• This issue arises due to the utilization of the CMQFX software thread, which is responsible for both protocol handling and traffic processing. When an uplink module is connected, a port probing mechanism for MACsec is triggered. This action leads to the CMQFX thread being hogged, resulting in CMQFX aborted messages and protocol instability.

• Protocol flaps lasting approximately 17-20 seconds
• CMQFX aborted messages in system logs
• Temporary disruption in traffic handling

• On EX4600 during optics/pic insertion we may notice hogging of software thread which may lead to CMQFX aborted messages printed in logs. This behaviour is expected considering the port probe mechanism for macsec getting triggered during such insertion. As a result of software thread spike we may notice some protocol flaps. 

• To minimize risk and impact:

  • Perform addition/removal of PICs or SFPs only during a Maintenance Window (MW).

  • Avoid making hardware changes during peak traffic periods.

PR raised for the issue: 1790097 ; https://prsearch.juniper.net/problemreport/PR1790097