300-420 Question #352: Real Exam Question with Answer & Explanation

Question

Refer to the exhibit. An architect is designing an ISIS solution with these requirements: - The backbone area will grow to 50 routers in the next 12 months. - Routers A1 and A2 must avoid suboptimal routing. - Summarization and route-leaking should be allowed in areas 49.002 and 49.003. Which solution must the architect select?

Options

• Aarea 49.000 L2, area 49.001 L1, area 49.002 L1, and area 49.003 L1
• Barea 49.000 L1, area 49.001 L2, area 49.002 L2, and area 49.003 L2
• Carea 49.000 L1, area 49.001 L1, area 49.002 L2, and area 49.003 L2
• Darea 49.000 L2, area 49.001 L2, area 49.002 L1, and area 49.003 L1

Explanation

To meet the ISIS design requirements for scalability, optimal routing, summarization, and route-leaking, the architect must configure areas 49.000 and 49.001 as L1, and areas 49.002 and 49.003 as L2.

Common mistakes.

• A. Configuring 49.000 as L2 and others as L1 would not create a scalable or optimally routed L2 backbone that spans across the central points (A1, A2) and allows summarization in the other specified areas.
• B. Configuring 49.000 as L1 and 49.001, 49.002, 49.003 as L2 would make 49.001 a backbone area, which might not align with the logical diagram or the need for A1 to handle both L1 for 49.000 and L2 for 49.002.
• D. Configuring 49.000 and 49.001 as L2 makes them part of the backbone, while 49.002 and 49.003 are L1; this structure might lead to less flexible summarization options in the specified areas compared to making 49.002/49.003 part of the L2 backbone.

Concept tested. ISIS area design and level configuration

Reference. https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_isis/configuration/xe-3s/irs-xe-3s-book/irs-isis-cfg.html

No community discussion yet for this question.