350-601 Storage Network Practice Question
An engineer notices that the LED of an FC interface is off on a Cisco MDS switch. The interface is up/up. What is the most likely cause?
⚠ Common exam trap
Cisco often tests the misconception that an LED off always indicates a hardware or link issue, when in fact the LED can be software-disabled independently of the interface operational state.
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
✓
The link is up but the LED is disabled in software configuration.
On Cisco MDS switches, the interface LED can be administratively disabled via the `no led` command in interface configuration mode, even when the interface is fully operational (up/up). This allows operators to selectively turn off LEDs for troubleshooting or to reduce visual noise in a data center, without affecting traffic. The LED being off while the interface shows up/up directly points to this software-based LED disablement.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The port LED firmware is corrupted.
Why it's wrong here
This is unlikely; LED behavior is simple.
- ✗
The interface is administratively down.
Why it's wrong here
The interface is up/up, so it is not admin down.
- ✓
The link is up but the LED is disabled in software configuration.
Why this is correct
On some MDS switches, the LED can be turned off via 'no led enable' interface command.
- ✗
The SFP is faulty.
Why it's wrong here
A faulty SFP would cause the interface to be down.
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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.