Cisco Certified Network Associate (CCNA) Practice Exam

What command would you use to specify a not so totally stubby area with no summary in OSPF?

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

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

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

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

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

The correct command for configuring a not-so-totally stubby area without summary routes in OSPF is indeed the one that specifies both 'nssa' and 'no-summary.' This configuration applies to an area that allows external routes while preventing summary routes from being sent into the area. In OSPF terminology, a 'not so totally stubby area' permits external routes, including Type 7 LSAs, while restricting summary routes from other areas. By using 'nssa no-summary,' you're enabling this specific area type and ensuring that summary routes from other areas are not propagated into it. This command effectively meets the requirement of controlling route propagation by combining the characteristics of an NSSA with the restriction of summarization. When considering the other options, the command that simply invokes 'nssa' does not prevent summary routes from entering the area. Meanwhile, the command with 'stub' does not accurately apply to NSSA configurations. The inclusion of 'no-summary' is crucial for achieving the desired routing behavior in scenarios requiring OSPF area control.