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MC-Lag vs EVPN

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  • 1.  MC-Lag vs EVPN

    Posted 09-22-2019 11:42

    Hi All, 


    We are replacing our decade old TOR switch with a QFX 5120. 


    In your opinon, should I run with MC-LAG into our hosts or use EVPN? 


    Of the two, which one is more resillient? Easier to config? 


    I ran across the MC-Lag configuration and it looks rather easy, so I'm somewhat leading that way, but doing basic research it seems MC-LAG will soon be retired, etc. 

  • 2.  RE: MC-Lag vs EVPN

    Posted 09-22-2019 18:24

    Hi RoutingFrames,

    If you have a relatively small setup with a few servers and mostly expect north-south traffic (servers with the rest of the routed network) rather than east-west (across servers), then MC-LAG will be simply and easy. However if you are looking for multi-homing, need scaling for east-west traffic and resilience, then EVPN-VXLAN topology with QFX5120 as leaf (VXLAN gateway) is the way to go.

    I've tried to share some useful links you might want to skim through to make a more informed decision :).

    QFX5120 Features:

    MC-LAG Caveat:

    EVPN vs MC-LAG discussion:

    Hope this helps.

    If this solves your problem, please mark this post as "Accepted Solution."
    Kudos are always appreciated :).

  • 3.  RE: MC-Lag vs EVPN

    Posted 09-23-2019 07:53

    Awesome Thanks.


    Most of our traffic is north-south, and the only east-west traffic is handled by the ESXi envrioment. 


    So, I'n the configuration I see I make a connection to the server as a simple lag, ae1 for instance. 


    Do I add a new lag for each host or do I make each host part of the same lag? 

  • 4.  RE: MC-Lag vs EVPN
    Best Answer

    Posted 09-23-2019 08:08

    Welcome RoutingFrames!


    It depends if you're forming the MC-LAG between two QFXs and the server - in that case, multiple physical servers will need multiple LAGs.  Else if you're making a LAG between the QFXs and an access switch where servers connect, then it needs a single LAG from the switch to the QFXs.


    Found a sample of each example here, please review and take a call based on your use-case:




    Hope this helps.




    If this solves your problem, please mark this post as "Accepted Solution."
    Kudos are always appreciated :).

  • 5.  RE: MC-Lag vs EVPN

    Posted 09-23-2019 08:28

    It would be option 1, just like I was thinking. 


    Thank you!! 

  • 6.  RE: MC-Lag vs EVPN

    Posted 09-25-2019 14:32

    @RoutingFrames you should really be having this discussion with your Partner-Juniper sales team, as to best approach, and long term goals.  The are various reason to use either 'design', and both will provide the capabilities you are looking for.  Your local people should be able to best direct you.


    BTW, an even potentially easier solution would be to VC 2 x QFX5120 together; this support if forth coming.