| In the figure, Area 2 is configured as
a stub area. No 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.
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 interarea routes (both
designated with an IA in the routing table; the default route will
also be denoted with an asterisk).
Note that each router in the stub
must be configured with the
area stub
command. The area
stub
command determines whether the
routers in the stub become neighbors. This command must be included
on all routers in the stub area if they are to exchange routing
information.
|