Nice input @JimmyPhelan  Here is the document explaining the connection monitoring mechanisms. https://documentation.meraki.com/MX/Firewall_and_Traffic_Shaping/Connection_Monitoring_for_WAN_Failover   ... View more

Load Balancing occurs on the active MX in a HA Pair. The other MX would be a Warm Spare (not active).   ... View more

Please note if a Virtual IP Address (VIP) is to be used then each uplink of the two MXs must share the same broadcast domain on the WAN side. ... View more