The answer is the port-channel has been configured with the 'port-channel max-links 1' command. This command explicitly limits the number of active member links in the EtherChannel to one, forcing all other physical ports into a suspended state even though they are identically configured and operational. The show etherchannel summary output confirms the port-channel is up, but only one link is active, which directly matches this restriction rather than a spanning-tree or VLAN mismatch issue that would affect all ports or prevent the channel from forming entirely. On the ENCOR 350-401 exam, this scenario tests your understanding of how the max-links parameter overrides the default load-balancing behavior, often appearing as a trick where students assume a physical-layer or configuration mismatch. A common memory tip is to think of max-links as a "capacity limiter" — if you see one active link and three suspended, remember that the command literally caps the number of active ports, not the total configured.
CCNP EtherChannel Practice Question
This 350-401 practice question tests your understanding of etherchannel. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
An engineer is troubleshooting an EtherChannel between two switches. The show etherchannel summary output shows that the port-channel is up, but only one physical link is active. The other three links are in a suspended state. The physical ports are all configured identically with the same VLAN allowed. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The port-channel has been configured with the 'port-channel max-links 1' command.
The correct answer is that the maximum number of active ports in the port-channel has been configured to 1. The wrong answers involve misconfigurations that would affect all ports or prevent the channel from forming.
Key principle: A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches.
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-channel has been configured with the 'channel-group 1 mode on' command, but the physical ports are using different speeds.
Why it's wrong here
Incorrect because speed mismatch would cause all ports to be down, not just three.
✗
The port-channel has been configured with the 'port-channel min-links 1' command.
Why it's wrong here
Incorrect because min-links specifies the minimum number of links to bring up the channel, not the maximum.
✓
The port-channel has been configured with the 'port-channel max-links 1' command.
Why this is correct
Correct because max-links limits the number of active ports in the EtherChannel.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Access ports place end devices into a single VLAN.
✗
The physical ports are in different VLANs.
Why it's wrong here
Incorrect because the scenario states they are all in the same VLAN.
Common exam traps
Common exam trap: an active trunk can still block the VLAN you need
A trunk being up does not prove every VLAN is crossing it. Check allowed VLAN lists, native VLAN mismatch, VLAN existence and access-port assignment.
Trap categories for this question
Scenario analysis trap
Incorrect because the scenario states they are all in the same VLAN.
Detailed technical explanation
How to think about this question
VLAN questions usually combine access-port and trunking clues. The key is to identify whether the issue is local to one switchport, caused by the trunk, or caused by the VLAN not existing where it needs to exist.
KKey Concepts to Remember
Access ports place end devices into a single VLAN.
Trunk ports carry multiple VLANs between switches.
Allowed VLAN lists decide which VLANs can cross a trunk.
Native VLAN mismatch can create confusing symptoms.
TExam Day Tips
→Use show vlan brief to verify access VLANs.
→Use show interfaces trunk to verify trunk state and allowed VLANs.
→Do not treat every same-VLAN issue as a routing problem.
Key takeaway
A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches.
Real-world example
How this comes up in practice
A help-desk technician troubleshoots why a newly connected PC cannot reach shared printers on the same floor. The cable is good, the switch port is active, but the PC is in VLAN 20 and the printers are in VLAN 10. The uplink trunk only allows VLAN 10. A trunk being up does not mean every VLAN crosses it.
What to study next
Got this wrong? Here's your next step.
Review VLAN allowed lists, native VLAN mismatch detection, and how to verify VLAN membership with show vlan brief and show interfaces trunk. Then practise related 350-401 questions on switching, trunking, and access-port configuration.
EtherChannel — This question tests EtherChannel — Access ports place end devices into a single VLAN..
What is the correct answer to this question?
The correct answer is: The port-channel has been configured with the 'port-channel max-links 1' command. — The correct answer is that the maximum number of active ports in the port-channel has been configured to 1. The wrong answers involve misconfigurations that would affect all ports or prevent the channel from forming.
What should I do if I get this 350-401 question wrong?
Review VLAN allowed lists, native VLAN mismatch detection, and how to verify VLAN membership with show vlan brief and show interfaces trunk. Then practise related 350-401 questions on switching, trunking, and access-port configuration.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Access ports place end devices into a single VLAN.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This 350-401 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 350-401 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.