300-420 Question #41: Real Exam Question with Answer & Explanation

Question

A router running ISIS is showing high CPU and bandwidth utilization. An engineer discovers that the router is configured as L1/L2 and has L1 and L2 neighbors. Which step optimizes the design to address the issue?

Options

• AMake this router a DIS for each of the interfaces
• BDisable the default behavior of advertising the default route on the L1/L2 router
• CConfigure the router to be either L1 or L2
• DConfigure each interface as either L1 or L2 circuit type

Explanation

{"question_number": 2, "question": "A router running ISIS is showing high CPU and bandwidth utilization.", "correct_answer": "D", "explanation": "An IS-IS router configured as L1/L2 maintains both Level 1 and Level 2 LSP databases and participates in SPF calculations at both levels on all interfaces. Configuring each interface as either an L1 or L2 circuit type (not both) limits which adjacency types form on each link. This prevents the router from processing unnecessary dual-level LSP flooding on every interface, reducing both CPU overhead (fewer SPF runs and database entries) and bandwidth (less LSP flooding). Option A (DIS) would increase the router's workload. Option B does not address the core processing issue. Option C (forcing the router to be L1 or L2 only) is more disruptive to the topology and may not be feasible; D is the targeted optimization.", "generated_by": "claude-sonnet", "llm_judge_score": 4}

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