Cisco Certified Network Associate (CCNA) Practice Exam

To configure a totally stubby area in OSPF, which command is used?

1. (config-router)#area AREA NUMBER stub no-summary

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

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

4. (config-router)#area AREA NUMBER no-summary

The correct answer is: (config-router)#area AREA NUMBER stub no-summary

The command to configure a totally stubby area in OSPF is indeed accurately described with the configuration of "area AREA NUMBER stub no-summary." This command does two things: it sets up an OSPF area as a stub area and prevents the advertisement of summary routes from the Area Border Router (ABR) into that area. In OSPF terminology, a totally stubby area is a special area type that restricts the types of route advertisements that can be sent to routers within the area. By marking the area as a stub first, routers within that area will ignore external routes advertised from other areas. The subsequent addition of the "no-summary" command ensures that not only external routes from other areas but also summary routes from the ABR are suppressed. As a result, routers within the totally stubby area will only receive default routes from the ABR, which helps reduce the routing table size and improve the efficiency of routing. The other options either do not fully configure a totally stubby area or misrepresent the configuration necessary for this specific area type. The choice that only includes "stub" will create a regular stub area instead of a totally stubby area. The command that uses "nssa" is meant for Not-So-