Posted on August 18, 2020 1:50 pm
 |  Asked by Amit Chudasama
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What happens if all CVP node goes down ? will my fabric still be running ?

what happend if all CVX node goes down ? will my VXLAN still functioning ?

Answered on August 18, 2020 2:00 pm

Hi Amit,

Thank you for contacting Arista.

If CVP node goes down and if you don't have node redundancy then devices would stop streaming the data to telemetry and your switches wouldn't get affected with forwarding data plane traffic unless you are making changes to the devices via CVP at the same time.

In case if CVX fails, VTEP's that have already learnt mac addresses via CVX will exist in the mac address table ,however  new macs will be flooded and no learning is possible on remote VTEP's.
However if we have static HER floodlist configured as a fall back incase if CVP fails, in that scenario traditional flood and learn approach happens and the remote VTEP's would learn the mac addresses.




Posted by Alexis Dacquay
Answered on August 18, 2020 2:22 pm

Yes and Yes: always working.

CloudVision is not part of the data plane.
CloudVision Portal is part of the management-plane (visibility, pushing new configurations)
CloudVision exChange is part of the control-plane (exchange reachability).

a) CVX failure

With CVX VXLAN service (VCS) then all new addresses would be flooded as BUM.
The reachability part of VXLAN include BUM traffic (Bcast, Unkown Unicast, Multicast), so it always works. It might not be optimal but it works.

CVX was made available as a VXLAN control-plane when there was nothing else than flood and learn.
Nowadays there is also EVPN and I would recommend EVPN as standalone VXLAN control-plane.

Consider CVX for SDN integration with other 3rd party controllers.

As Bhavana mentioned, you can configure CVX's VXLAN service (CVS) to use flood and learn by default. It can be preferred, for better support of Disaster recovery sites.

To enable flood-and-learn as control-plane mechanism, go in CVX, vxlan, and configure flood-and-learn for MAC learning.

VXLAN is still used to build and distribute flood-list.
If CVX isn't reachable then it mean you can have a new VTEP added in every switches' flood list.
It meant you cannot add a new switch during the CVX failure.

If that is critical to you, then either build a cluster of CVX, or choose a decentralised control-plane (EVPN).

1) CVP outage.
CVP does not participate in the forwarding decision or distribution of control-plane information, it is for the management plane: automating upgrades, change/addition/removal of configs, Operations automation. But it's not part of the Ethernet/IP network.

Does this answer the questions?


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