CCIE Data Center (legacy) — Question 114

Traffic drop for FCoE is experienced across a Nexus 5548 switch. What is a possible cause?

Answer options

• A. Server's CNA does not support DCBX and PFC TLV was not negotiated.
• B. A "no-drop" class has not been configured for FCoE.
• C. The system is running with the default QOS policies.
• D. The link is oversubscribed.

Correct answer: A

Explanation

The correct answer, A, indicates that if the server's CNA does not support DCBX, it cannot negotiate the necessary PFC TLV, leading to traffic drops. Option B is incorrect because a 'no-drop' class, while beneficial, is not the primary cause in this scenario. Option C is also wrong as default QOS policies may not specifically lead to traffic drops. Lastly, option D suggests oversubscription, which may cause congestion but is not directly linked to the FCoE traffic drop in this context.