Draytek Vigor2912 User Manual page 120

Active When
After finished the above settings, click OK to save the settings.
Vigor2912 Series User's Guide
When the data traffic is large, the WAN interface with the
function enabled will balance the data transmission
automatically among all of the WAN interfaces in
connection status.
If you choose Failover as the Active Mode, the option of
Active When will appear.

Any of the selected WAN disconnect – Such WAN
connection will be activated when any selected WAN
interface (checked below) disconnects.

All of the selected WAN disconnect – Such WAN
connection will be activated only when all of selected
WAN interfaces (checked below) disconnect.

Check boxes for WAN1 to WAN3 – Specify the
WAN interface by checking the WAN box.
110