350-601 Storage Network Practice Question
A storage administrator is troubleshooting FCoE performance issues between a Cisco UCS FI and a storage array. The fabric is configured with FIP snooping and DCB. The administrator checks the FCoE interface counters and sees many dropped frames due to 'no buffer space'. What is the most likely root cause?
⚠ Common exam trap
Cisco often tests the distinction between 'no buffer space' drops (caused by PFC/flow control mismatches) and other drop types like 'output drops' or 'CRC errors', leading candidates to incorrectly blame jumbo frames or VLAN issues.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Priority flow control settings are mismatched between the upstream switch and the storage array
The 'no buffer space' drops on FCoE interfaces indicate that the receive buffers are being exhausted, which is a classic symptom of Priority Flow Control (PFC) being misconfigured or mismatched between the upstream switch and the storage array. PFC (IEEE 802.1Qbb) is essential for lossless FCoE transport; if one side sends pause frames that the other does not honor, or if the PFC priorities are not aligned, buffers overflow and frames are dropped. This directly explains the observed counter behavior.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Jumbo frames are disabled on the switch ports
Why it's wrong here
Jumbo frames are required for FCoE, but disabling them would cause different errors.
- ✗
The FCoE VLAN is not trunked to the storage array
Why it's wrong here
Missing VLAN trunking would cause no connectivity, not buffer drops.
- ✗
FIP snooping is not enabled on the FCoE VLAN
Why it's wrong here
FIP snooping prevents unauthorized FCoE devices, doesn't cause buffer drops.
- ✓
Priority flow control settings are mismatched between the upstream switch and the storage array
Why this is correct
PFC mismatch can cause buffer exhaustion and drops.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-601 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 350-601 exam.