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Change MTU size on EX2300-C involve power cycle ?

  • 1.  Change MTU size on EX2300-C involve power cycle ?

    Posted 01-12-2021 09:01
    bonjour all, 
       when doing a test in lab yesterday, I was surprised that a change in mtu size on EX-2300C forced me to do a power cycle on the switch. 
    I was connected in console and simply issued a set interface ge-0/0/11 mtu  nnnn   command. I was at that moment pinging my switch successfully through that interface. 
    I issued a commit confirmed 3, then  promptly lost the pings. 
    no problem, I said to myself, everything will be back in 3 mns. 
    But the pings never came back even after the console informed me that the rollback had occured !,  the only way I found of getting back my ping was to do a power cycle on the switch. 
    the switch is running 18.2R3-S3.11
    I don't mind having to reboot after a change in mtu, but losing access to the switch even if I do  a commit confirmed is kind of scary. 
    Also, If I ever end up having to do this on a remote switch,  is there such a thing as a "commit and reboot "  command ? 

    as always, thanks for your help. 
    merci,
    Michel
     


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    Michel Lapointe
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  • 2.  RE: Change MTU size on EX2300-C involve power cycle ?

     
    Posted 01-16-2021 12:44
    Did the mtu change on the other side of the link at the same time?

    I've not had a lot of ex but changing mtu on mx and acx has been consistently immediate and with only a link bounce when done on both sides of the link roughly the same time.

    ------------------------------
    Steve Puluka BSEET - Juniper Ambassador
    IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP)
    http://puluka.com/home
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  • 3.  RE: Change MTU size on EX2300-C involve power cycle ?

    Posted 01-16-2021 16:42

    Bonjour Spuluka,

                   Thanks for inquiring.

                   No – no change at all on the other side.

                  

                   I tried it 2 times, and the same thing happened. Last year, my colleague did the same thing hoping to pinpoint a problem remotely , and he ended up losing all contact and basically calling the janitor to reset the switch J

                   I guess next step is now to open a case with Juniper and hope they can duplicate.

                   I'll keep you posted.

     

    __________________________________________

    Michel Lapointe

    Projet GIRAT 2.0

    Michel.lapointe@girat.org

    Cell : (819) 279-0844

     

    GIRAT     http://www.girat.org

    (Gestion de l'inforoute régionale de l'Abitibi-Témiscamingue)

    Girat_Image30x116

     

     






  • 4.  RE: Change MTU size on EX2300-C involve power cycle ?

     
    Posted 01-16-2021 20:25
    The reason I asked about the other side is mtu does need to match on the connected ports.  So I suspect the issue you are seeing is related to the mismatch in mtu on the link.

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



  • 5.  RE: Change MTU size on EX2300-C involve power cycle ?

    Posted 01-17-2021 12:24
    good point, Steve - I'll give it a try on my EX. 
    What is your call , though, on the rollback not restablishing the communication ?
    Thanks,
    Michel

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    Michel Lapointe
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  • 6.  RE: Change MTU size on EX2300-C involve power cycle ?

     
    Posted 01-17-2021 18:23
    I'd guess that the link did not flap.  I've generally had to see the link flap during mtu change events.  
    If it happens again try disable and enable the port.

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