Designing Cisco Network Service Architectures (ARCH, legacy) — Question 60

An engineer is designing an OSPF network with multiple nonbackbone areas connected to the backbone area via a hub-and-spoke topology. Each hub-and-spoke topology has a large number of spoke routers connected to the hub that is functioning as an ABR to provide better segmentation. Which two actions improve the stability of this design? (Choose two.)

Answer options

• A. Configure hub-and-spoke areas as stub.
• B. Implement summarization on the ASBR routers in the backbone area.
• C. Use External Type 2 metric across the OSPF domain.
• D. Configure hub-and-spoke areas as totally stubby.
• E. Implement summarization on the ABR routers of hub-and-spoke areas.

Correct answer: B, E

Explanation

Implementing summarization on the ASBR routers in the backbone area (option B) reduces the number of routes that need to be processed, enhancing stability. Similarly, summarization on the ABR routers of the hub-and-spoke areas (option E) simplifies routing within those areas. The other options, while useful in certain contexts, do not specifically address stability improvements for this design.