Expand all | Collapse all

Network loop detection options with EVPN/VXLAN

  • 1.  Network loop detection options with EVPN/VXLAN

    Posted 10-21-2020 11:05



    We are currently in the progress of deploying a EVPN/VXLAN (Spine-Leaf) architecture in our datacenters. This used to  be a flat layer 2 network with seperation of networks by using VLANs. One off our internal "customers" (same company) has its office networks connected to our datacenters. One connection to DC-A using a dark fiber and one connection (backup) using EVPN (leased connection) to DC-B as a backup for when the fiber might fail. These connections are an extiontion  off the office network to equipment in the DC's.


    So for example: the customer network has VLAN 10 tagged on their dark fiber and VLAN 10 tagged on the EVPN. The switches in both datacenters are interconnected over their own dark fibers and have the VLAN 10 tagged on the trunk between them. So pretty much all flat layer 2. Currently we have STP configured with a lower priority on the EVPN to prevents loops. See image:


    In the new situation we would still have the dark fibre and the EVPN connected to a leaf switch each in a datacenter With their VLAN tags VLAN10. On the VXLAN we would define the VLAN 10 with a VNI off 1001. See simplified image below:


    What are the posibilities dealing with loops in this scenario? Since we can't use STP with EVPN/VXLAN is this even possible?


    Like to hear from you!



  • 2.  Re: Network loop detection options with EVPN/VXLAN

    Posted 10-21-2020 11:18

    I think I replied to similar question is some other thread, but 20.2R2 code (due out mid-to-late Nov) will include a loop protection mechanism for use in EVPN environments.  Not sure the exact implementation, but supposed to be there.

  • 3.  Re: Network loop detection options with EVPN/VXLAN

    Posted 10-22-2020 00:59

    Good to know they are working on this, but we like to run the stable recomanded versions.


    Are there any solutions possible in Junos 18.4R2?

  • 4.  Re: Network loop detection options with EVPN/VXLAN

    Posted 10-22-2020 05:24

    No for 18.4.  This is a new feature being introduced in 20.2R2.  20.2R2 will become a recommended release for EVPN.  TAC suggested releases do NOT cover specific 'feature use cases', just general perceived stability based upon Case/downloads/etc.

    For EVPm the releases have been 18.1R4-S[latest], then 18.4R2-S[latest] and soon 20.2R2 once this release is out.  Next will be 20.4, and then so forth (.2 and .4) going forward.  I would hope eventually every release will be EVPN ready, but right we are targeting very specific releases.  This is for all QFX and EX4300-MP today.  I am not sure about MX.  Much of this also has connection to CEM (Contrail Enterprise Multicloud) which uses Contrail Command as it user interface, and has an IP/EVPN Fabric Manager.

  • 5.  RE: Re: Network loop detection options with EVPN/VXLAN

    Posted 11-15-2020 05:23
    I've gone through the QFX and EX release for 20.2R2 and both note 'There are no new features or enhancements to existing features ... in Junos OS Release 20.2R2'

    Has this been delayed?