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  • 1.  Connected device on switch indicates false positive link state

    Posted 09-14-2023 06:08

    Hello,

    we are facing unexpected behaviour of a SFP+ module (3th party) on a Juniper QFX5120. When disabling a port on the switch the connected device that is connected to the device indicates an active linkstate resulting in a false positive state.

    We suspect this is related to the optical transmitter in the  SFP+ module that is not being disabled  when the switch port is in disabled state.

    questions we have:

    • For trouble shooting purposes, can this be confirmed by a command on the command line on the Juniper switch, to analyze the SFP+ module?
    • What SFP+ module specifications should be looked for, to avoid this issue.

    thanks!



    ------------------------------
    Joep Leurs
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  • 2.  RE: Connected device on switch indicates false positive link state

    Posted 09-14-2023 06:10

    You can confirm the status of the optics levels using

    show interface diagnostics optics



    ------------------------------
    Steve Puluka BSEET - Juniper Ambassador
    IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP - Retired)
    http://puluka.com/home
    ------------------------------



  • 3.  RE: Connected device on switch indicates false positive link state

    Posted 09-14-2023 10:47

    Hi Steve,

    Does this command also apply to copper SFP+ transceivers ?

    Curious what output of this command can relate to the false positive behaviour we are seeing now.



    ------------------------------
    Joep Leurs
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  • 4.  RE: Connected device on switch indicates false positive link state

    Posted 09-14-2023 11:28

    Hi,

    If u have juniper SFP+ then please replace it to make sure it not related to switch. If after replace all good then it related that non-juniper SFP is not compatible with juniper switch. Please take note based on my previous exprience the non-juniper sfp can make the juniper switch behaviour unexpected,

    Thanks




  • 5.  RE: Connected device on switch indicates false positive link state

    Posted 09-16-2023 06:51

    The command would not help with copper sfp.  I was looking to see if the transmit and receive power settings on an normal optic were correctly stopped when a port was disabled.

    The test kronicklez mentioned with a Juniper sfp will test the communications between the switch and the optics firmware.  Juniper does not actively prevent 3rd party optics like some vendors.  But the optic manufacturer has to have communications setup to work with multiple vendors and this communication may not be working for this vender optic.



    ------------------------------
    Steve Puluka BSEET - Juniper Ambassador
    IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP - Retired)
    http://puluka.com/home
    ------------------------------