| In the figure, the keyword no-summary
has been added to the area
stub command on R3. This
keyword causes summary routes (delivered by both Type 3 and Type 4
LSAs) to also be blocked from the stub. Each router in the stub
picks the closest ABR as a gateway to all other networks outside the
area.
The only routes that will appear in
R4's routing table are intra-area routes (designated with an O in the
routing table) and the default route. No interarea routes
(designated with an IA in the routing table) will be included.
Note that it is necessary to
configure the no-summary
keyword only on the totally stubby border routers, because the area
is already configured as stub.
|