By default, a PPPoE / DHCP connection is assigned a priority of 5. For static routes by default, a priority of 10 is assigned.
The route with the lowest priority is the preferred route.
If the PPPoE connection is to be a backup connection, for example using a xDSL in case the main fibre goes down. The default settings will mean that the xDSL link will become the preferred route and no traffic will go over the main fibre.
In 5.4, there is no option to change the priority in the GUI, this needs to be done by CLI
To changed, in CLI go to the interface and “set priority xx”
configure system interface
edit XXX XXX = interface name
set priority YY YY = priority value
To see the result in the routing table in CLI type Get router info routing-table all