CCNA Routing and Switching (legacy) — Question 108

Which symptom most commonly indicates that two connecting interfaces are configured with a duplex mismatch?

Answer options

• A. an interface with a down/down status
• B. the spanning-tree process shutting down
• C. collisions on the interface
• D. an interface with an up/down status

Correct answer: C

Explanation

Collisions on the interface are a primary indicator of a duplex mismatch because they occur when one side of the connection is set to full duplex and the other to half duplex. The other options do not specifically indicate a duplex mismatch; for instance, an up/down status can occur for various reasons unrelated to duplex settings.