A flag indicating whether RIP should perform
border filtering on subnet routes when crossing
a network boundary. Interfaces that are configured
for RIPv1 or RIPv1-compatible mode must always
filter subnets at network boundaries. Interfaces
configured for RIPv2 mode will only filter subnets
if this flag is set to 'true'. Setting this to
'true' will result in all subnets within a
class-based network to be summarized using a single
route for the subnet number, which can decrease the
size of the routing tables. However, if any networks
are discontiguous, this flag should be set to 'false'
for proper routing.