Cisco Certified Network Associate (CCNA) Practice Exam

What command is utilized to flag an OSPF area as a stub?

1. (config-router)#area AREA NUMBER nssa

2. (config-router)#area AREA NUMBER stub

3. (config-router)#area AREA NUMBER totally-stubby

4. (config-router)#area AREA NUMBER default

The correct answer is: (config-router)#area AREA NUMBER stub

Flagging an OSPF area as a stub is essential for optimizing routing in an OSPF network by reducing the amount of routing information exchanged with that area. The command that achieves this is the one that includes the term "stub." When this command is applied, the routers in that area will not receive external route information (type 5 LSAs) and will instead use a default route to reach destinations outside the stub area. The ability to configure an area as stub is particularly beneficial in scenarios where an area does not require full routing information—such as when connecting branch offices to a headquarters—thus reducing processing overhead and memory utilization on routers within that area. While other options reference different configurations related to OSPF areas, they do not effectively convey the concept of a stub area. For instance, specifying "nssa" refers to a Not-So-Stubby Area, which is a variation of the stub concept but allows for the importing of external routes. The option that mentions "totally-stubby" seems to reference a similar notion but requires a different command and context. Finally, the default option does not pertain to the area designation, making it irrelevant in this context. Thus, choosing the correct command that uses "stub"