This section describes Enhanced HA.
The Enhanced HA eliminates the need for L2 Switches on WAN side of the Edges. The Enhanced HA option is chosen when the Active Edge detects different WAN link(s) connected to the Standby Edge when compared to the link(s) connected to itself.
The following figure shows a conceptual overview of Enhanced HA.
The Edges, one Active and one Standby, are connected by L1 ports to establish a failover link. The Standby SD-WAN Edge blocks all ports except the L1 port for the failover link. As shown in the figure, the Active Edge establishes overlay tunnels on both WAN links (connected to itself and the Standby Edge).
In order to leverage the WAN link connected to the Standby Edge, the Active Edge establishes the overlay tunnel through the HA link. Traffic from the LAN is forwarded to the Active Edge. The business policy for the branch defines the traffic distribution across the overlay tunnels.