A BGP EVPN network is a full mesh of unicast vxLan tunnels between all leaf switches that
are part of the same vLAN.
In a BGP EVPN network:
IP network in the fabric is used as underlay to deliver L2 or L3 traffic between the
hosts. VxLAN tunnels are used as overlay for delivering traffic from leaf to leaf
with each leaf serving as a VTEP.
A BGP session is established between each pair of directly connected routers.
At each node the user configures the VLANs to exchange traffic with the Hosts. Each
VLAN is associated with a VNI, the identifier for the vxLAN tunnel in the fabric
between leaf switches
BGP distributes an IMR (Inclusive Multicast Route) which associates the VNI and
participating VTEPs. This route information eventually reaches all leaf switches,
where the vxLan tunnel to the remote peer is created.
