| In the main figure, area 2 is defined as
the stub area. No external routes from the external autonomous
system will be forwarded into the stub.
The last line in each configuration,
area 2 stub, defines
the stub area. The
area stub default-cost
has not been
configured on R3, so this router will advertise 0.0.0.0 (the default
route) with a default cost metric of 1 plus any internal costs.
Note Each router in the stub must be configured with the
area stub
command.
The only routes that will appear in R4's routing table are
intra-area routes (designated with an O in the routing table), the
default route, and inter-area routes (both designated with an IA in
the routing table; the default route will also be denoted with an
asterisk).
Note The
area stub
command determines whether the
routers in the stub become neighbors. This command must be included
on all routers in the stub if they are to exchange routing
information.
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