5.4 Using Stub and Totally Stub Areas
5.4.5 OSPF totally stubby configuration example
In the main figure, the keyword no-summary has been added to the area stub command on R3. This keyword causes summary routes (inter-area) to also be blocked from the stub. Each router in the stub picks the closest ABR as a gateway to everything 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 inter-area routes (designated with an IA in the routing table) will be included.

Note It is necessary to configure the no-summary keyword only on the totally stubby border routers, because the area is already configured as stub.

Lab Activity
  In this lab, you will learn how to configure OSPF Area 1 as Stub and Totally Stubby.