VTEPs need to know which remote VTEP hosts which MAC address.
Flood-and-learn: Broadcasts replicate to all VTEPs. VTEPs learn MACs from traffic. Simple but creates storms at scale.
Multicast underlay: Broadcast maps to multicast groups. Reduces replication. Requires multicast support.
BGP EVPN: The preferred approach. BGP advertises MACs and their VTEPs. No flooding needed.
EVPN benefits:
- No flooding for unknown unicast
- ARP suppression
- Multi-homing support
- Integrated routing
BGP EVPN is the standard for modern VXLAN.