CCIE Routing and Switching (legacy) — Question 4

Which command enables L2 QoS support in all VLANs (including the native VLAN)?

Answer options

• A. switchport priority extend cos
• B. mls qos trust dscp
• C. mls qos rewrite ip dscp
• D. switchport trunk native vlan tag

Correct answer: D

Explanation

The correct answer, D, enables the tagging of the native VLAN, allowing L2 QoS to be supported across all VLANs. Options A, B, and C do not provide the necessary configuration to extend QoS support to the native VLAN and therefore do not meet the requirement of the question.