The DR Election Priority option is used when people
want to have control over which router is elected as
the DR, irrespective of the address of routers on the
same LAN. This is needed on LANs where new routers
can be added and configured by different operators.
The numerically larger priority is always preferred.
The DR election priority is used only when all routers
on the LAN include this option in their Hellos.
A value of zero will disable this feature on the LAN.