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  • 1.  EVPN-VxLan between 2 VSX

    Posted Mar 31, 2025 06:41 AM

    Greetings,

    simply questions: is it possible to configure EVPN-VxLan between 2 VSX Clusters? The online documentation refers always to an spine and leaf configuration.

    Background information:

    Customer has two DataCenter - in each DC is a CX8325 pair as VSX.

    At the moment we have a Layer 2 Multi Chassi LAG between the Clusters. An external Service Provider has also two Switches with Multi Chassi LAG in each DC (Nvidia SN2010).

    The 4x Nvidia devices are also connectected to each other - to avoid a loop (the external provider does not want to configure STP) the idea was to create an Overlay Network with EVPN.

    thanks in advance



  • 2.  RE: EVPN-VxLan between 2 VSX

    Posted Mar 31, 2025 06:57 AM

    Hi

     

    Yes, basically, that is possible. It simply does not follow the (standard) Leaf-Spine architecture but technically, this is absolutely no problem. It's a different use case.

    Keep in mind that running an overlay requires a larger MTU (e.g. 9198 to enable the transport of jumbo frames in your L2VNIs) to cover the additional bytes for VXLAN headers.

     

    Depending on your needs, you may configure L3 addresses to either the physical interfaces of your DCIs or to any VLAN(s) that are transported across the DCIs. Instead of
    having a rather hierarchical design with the Spines on top and the Leaf below, you would have some sort of full-mesh between the 4 switches (2 VSX pairs).

     

    I have a very similar use case already in production. Works perfectly.

     

    Let me know if you need anyone to discuss your idea in further details.

     

     

    Regards,

    Thomas

     

     






  • 3.  RE: EVPN-VxLan between 2 VSX

    Posted Mar 31, 2025 07:19 AM

    Okay thanks

    For my understanding:

    • Every 8325 needs an IP Adress (either as subnet or point to point) on vlan or physical link for the OPF
    • on each i create an loopback interface with different IP Adresses for the BGP and a second loopback with the same IP address per VSX (for the vxlan interface)
    • configure the bgp with all neighbors and than the evpn settings for the vlans

    is this rigth?


    Original Message


  • 4.  RE: EVPN-VxLan between 2 VSX

    Posted Mar 31, 2025 07:19 AM

    If the Nvidia switches are also connected with each other, you will still have a loop in the network. VXLAN will not solve that for you. I would suggest to remove the DCI connection between the Nvidia switches and let the traffic be handled by the 8325 switches. Or move to L3 connection between the 8325 and Nvidia switches



    ------------------------------
    Willem Bargeman
    Systems Engineer Aruba
    ACEX #125
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    Original Message


  • 5.  RE: EVPN-VxLan between 2 VSX

    Posted Apr 11, 2025 05:49 AM

    You may want to check my old post her post about the same topic, there are some examples and diagrams

    https://community.arubanetworks.com/discussion/routing-off-of-vxlan-to-expternal-router




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    -- tommyd
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