In case the Edges switch to the enhanced HA option, the Active SD-WAN Edge will exchange BGP routes over the HA link. BGP on the Active Edge can now establish neighborship with a peer connected only to the standby Edge’s WAN link.
This will enable the Active Edge to learn routes from the WAN link(s) connected to the Standby Edge. The routing daemon on standby will not involve in any of the functionality. The standby Edge itself will just do a pass-through.