Exam 300-420 topic 1 question 271 discussion

Refer to the exhibit.



An engineer is designing a hierarchical ISIS solution for an enterprise customer with these requirements:
• Users in areas 25 and 55 send and receive traffic from both backbone areas.
• Link flaps in areas 35 and 45 must not impact other areas.
• Routers will double within the next 12 months in areas 35 and 45.

Which design must the engineer select?