Configuring Fabric Guard

Currently, NetVisor OS detects a Layer 2 loop using STP, LLDP, or loop detect code. However if a third party device connected to a Arista Networks switch consumes LLDP such as a hypervisor vSwitch, and you configure the port as an edge port, NetVisor OS cannot detect loops in the network.

If you configure a port as fabric-guard port, NetVisor OS triggers sending global discovery multicast packets on this port after the port is physically up and in an adjacency wait state. If a port with fabric-guard configuration receives a global discovery packet, NetVisor OS disables the port in the same way LLDP disables the port when receiving messages from the same switch. 

To enable fabric guard, use the following syntax:

CLI (network-admin@Leaf1) > port-config-modify port port-number fabric-guard

To disable fabric guard, use the following syntax:

CLI (network-admin@Leaf1) > port-config-modify port port-number no-fabric-guard

In order to re-enable the port once you fix the loop, you must  manually enable the port using the command, port-config-modify port port-number enable.