- A
The LACP system priority on the active side must be lower than the auto side.
Why wrong: LACP system priority does not need to be manually set or match for EtherChannel to form; it only determines which ports become active when the bundle has more members than allowed, not basic negotiation.
- B
The mode 'auto' is a PAgP negotiation mode that is incompatible with the LACP active mode.
Mode auto is part of Cisco's PAgP, not LACP. It cannot negotiate with an interface using LACP active mode, so the bundle fails.
- C
LACP requires one side to be active and the other passive; two active interfaces will not bundle.
Why wrong: LACP works with active/active, active/passive; only passive/passive fails to negotiate. The statement is inaccurate.
- D
The physical interfaces must be shut down and then re-enabled after configuring LACP for the bundle to form.
Why wrong: EtherChannel negotiation begins immediately upon configuration; a manual reset is unnecessary.
CCNA Switching and Network Access Practice Question
This 200-301 practice question tests your understanding of switching and network access. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. 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.
A network engineer configures an EtherChannel between two switches. Switch A's interface is set with channel-group 1 mode active, while Switch B's identical interface is set with channel-group 1 mode auto. When verifying with show etherchannel summary, the engineer observes that the port-channel interface is down and the physical interfaces are not bundled. What is the most likely cause of the problem?
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 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 mode 'auto' is a PAgP negotiation mode that is incompatible with the LACP active mode.
Option B is correct because 'active' is an LACP mode that initiates negotiations, while 'auto' is a PAgP mode that passively waits for PAgP packets. Since LACP and PAgP are incompatible protocols, the interfaces will never negotiate a bundle, leaving the port-channel down. The engineer must use matching protocol modes (e.g., both LACP active/passive or both PAgP desirable/auto) for EtherChannel to form.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 LACP system priority on the active side must be lower than the auto side.
Why it's wrong here
LACP system priority does not need to be manually set or match for EtherChannel to form; it only determines which ports become active when the bundle has more members than allowed, not basic negotiation.
- ✓
The mode 'auto' is a PAgP negotiation mode that is incompatible with the LACP active mode.
Why this is correct
Mode auto is part of Cisco's PAgP, not LACP. It cannot negotiate with an interface using LACP active mode, so the bundle fails.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
LACP requires one side to be active and the other passive; two active interfaces will not bundle.
Why it's wrong here
LACP works with active/active, active/passive; only passive/passive fails to negotiate. The statement is inaccurate.
- ✗
The physical interfaces must be shut down and then re-enabled after configuring LACP for the bundle to form.
Why it's wrong here
EtherChannel negotiation begins immediately upon configuration; a manual reset is unnecessary.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓The mode 'auto' is a PAgP negotiation mode that is incompatible with the LACP active mode.Correct answer▾
Why this is correct
Mode auto is part of Cisco's PAgP, not LACP. It cannot negotiate with an interface using LACP active mode, so the bundle fails.
✗The LACP system priority on the active side must be lower than the auto side.Wrong answer — click to see why▾
Why this is wrong here
LACP priority is not required for basic negotiation and does not cause a failure to bundle.
✗LACP requires one side to be active and the other passive; two active interfaces will not bundle.Wrong answer — click to see why▾
Why this is wrong here
Active/active LACP successfully negotiates, so this is not the cause.
✗The physical interfaces must be shut down and then re-enabled after configuring LACP for the bundle to form.Wrong answer — click to see why▾
Why this is wrong here
Bouncing interfaces is not required to trigger LACP negotiation.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the confusion between LACP and PAgP mode keywords, especially the similarity between 'active' (LACP) and 'auto' (PAgP), leading candidates to assume they are compatible or to focus on priority or interface state rather than protocol mismatch.
Detailed technical explanation
How to think about this question
LACP (IEEE 802.3ad) uses active and passive modes, while PAgP (Cisco proprietary) uses desirable and auto modes. The 'channel-group 1 mode active' command sends LACP packets, but 'channel-group 1 mode auto' sends PAgP packets; since the two protocols use different frame formats and negotiation logic, they cannot form a bundle. In real-world scenarios, this mismatch often occurs when engineers mix commands from different switch platforms or misremember the mode keywords, leading to a non-functional EtherChannel that requires reconfiguration to a consistent protocol.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Questions learners often ask
What does this 200-301 question test?
Switching and Network Access — This question tests Switching and Network Access — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The mode 'auto' is a PAgP negotiation mode that is incompatible with the LACP active mode. — Option B is correct because 'active' is an LACP mode that initiates negotiations, while 'auto' is a PAgP mode that passively waits for PAgP packets. Since LACP and PAgP are incompatible protocols, the interfaces will never negotiate a bundle, leaving the port-channel down. The engineer must use matching protocol modes (e.g., both LACP active/passive or both PAgP desirable/auto) for EtherChannel to form.
What should I do if I get this 200-301 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jun 25, 2026
This 200-301 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 200-301 exam.
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