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PR 1499422 – FPC goes down whenever 100G transceivers are inserted on the network port of QFX5110-48S



Article ID: TSB17774 TECHNICAL_BULLETINS Last Updated: 06 May 2020Version: 4.0
Alert Type:
PSN - Product Support Notification
Product Affected:
Alert Description:

This Technical Support Bulletin (TSB) has been opened to inform Juniper network customers about PR1499422. On the QFX5110-48S device inserting any QSFP-100G-transceiver on one or more network ports will cause FPC state to flap. In the problem state FPC will go down as soon as the 100G link comes up and FPC flap will be seen every 90 seconds.

During the problem state running the cli command “show chassis fpc” will not yield any output for next 90 seconds until the FPC comes online again. Once FPC state transitions back to “online” state, the 100G transceivers gets detected and fpc flap is seen again. This behavior will continue as long as one of the 100G transceivers remains connected to the QFX device in question. If all the 100G interface gets disabled from CLI  or they are physically removed from the QFX switch, the FPC flap will no longer be seen.  


  • When QFX5110-48S Model is used. 

  • When QSFP-100G transceivers are inserted on the appropriate network ports. 


  • This issue is not applicable when 100G-QSFP is used as a Virtual Chassis Port (VCP)  on QFX5110-48S

Workaround:  ​


Affected JUNOS software releases: 





We are currently working on a software fix for resolving this issue on Junos 19.3R2-S3 and 18.2R3-S5 releases. 
Please check PR1499422 for the complete list of software releases which has the fix committed for this issue (login required.) 

Modification History:
2020-05-05: Fixed URL for PR1499422.
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