L2 Forwarding in VXLAN

VXLAN learns unicast source MAC addresses similar to hosts off physical ports. When a packet is de-encapsulated from a VXLAN tunnel, the source MAC is checked against the MAC table and bound to the tunnel interface index or if it is not present, it is learned. If the unicast source is in the MAC table but on a different port or tunnel to it, it is considered a move. The MAC table is used as the destination match to send traffic to a remote tunnel partner. Any unknown destination addresses are forwarded to all VTEP partners, configured with a common Virtual Network Identifier (VNI).

Broadcast addresses are handled similar to unknown destination addresses and flooded to all tunnels with mapped and configured VNI. Floods are copied to each unicast VTEP tunnel. Multicast addresses are not filtered, they are treated like a flood when going to multiple tunnel destinations.