Cisco Certified Network Associate (CCNA) Practice Exam

Which type of routes does a totally stubby area use to receive default routing?

1. Type 1 LSA

2. Type 3 LSA

3. Type 2 LSA

4. Type 7 LSA

The correct answer is: Type 3 LSA

A totally stubby area is a specific type of OSPF (Open Shortest Path First) area that allows for certain limitations on the types of routes that can be advertised into it. In a totally stubby area, the only external route Type that is permitted is a default route. The correct choice concerning how a totally stubby area receives default routing is indeed Type 3 LSA (Link-State Advertisement). Type 3 LSAs are used to advertise inter-area routes, essentially allowing the area to receive summarized routes from other OSPF areas. However, in a totally stubby area, Type 3 LSAs are restricted to a default route only, which is represented as a 0.0.0.0 route, usually injected by a designated router (DR) within the backbone area for that purpose. Type 1 LSAs describe internal OSPF routes within the area and would not pertain to route summarization for areas. Type 2 LSAs represent OSPF networks advertised by a DR and are not relevant for external route advertisement in this context. Type 7 LSAs are specific to NSSA (Not So Stubby Area) environments and are used for external route advertisements, which again would not apply to totally