The answer is LACP active on one side is incompatible with mode on on the other side. This is because LACP active and LACP passive are the only two modes that can negotiate a dynamic EtherChannel together, while the static mode on forces a manual bundle without any negotiation protocol. When one switch uses LACP active, it actively sends LACP packets, but the other switch using mode on does not participate in any protocol negotiation, so the ports remain isolated. On the CCNA 200-301 v2 exam, this scenario tests your understanding of EtherChannel mode incompatibility across LACP, PAgP, and static configurations—a common trap is assuming any two active modes will work, but static mode on is protocol-agnostic and only pairs with another static on. Remember the memory tip: “Active and passive are LACP’s pair; static on is a lone wolf that needs another static on.”
CCNA Network Services and Security Practice Question
This 200-301 practice question tests your understanding of network services and security. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. A key principle to apply: etherChannel bundles multiple physical switch ports into a single logical link to increase bandwidth and provide redundancy.. 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.
Exhibit
SW1:
interface range g1/0/1-2
channel-group 5 mode active
SW2:
interface range g1/0/1-2
channel-group 5 mode on
Two switches are configured to form an EtherChannel, but the bundle never comes up. Which explanation best describes this scenario?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "best"
Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Clue: "never"
Why it matters: Absolute qualifier. True only if the statement has zero exceptions — be cautious of options that seem obvious but break down in edge cases.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
LACP active on one side is incompatible with mode on on the other side.
One side is using LACP active mode and the other side is forcing a static channel-group with mode on. Those modes are not compatible. LACP needs active or passive on both sides, while PAgP uses desirable or auto, and static mode on expects a manual bundle on the other side.
Key principle: EtherChannel bundles multiple physical switch ports into a single logical link to increase bandwidth and provide redundancy.
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 switches are using different native VLANs.
Why it's wrong here
That may cause trunk issues, but it does not explain this specific EtherChannel mode mismatch.
When this WOULD be correct
In a different question, if the context involved troubleshooting a trunk link where the native VLANs on both switches were indeed mismatched, this option would be correct. For example, if the question specified that the EtherChannel was configured for trunking and the native VLANs were different, it could lead to a failure in establishing the trunk.
✓
LACP active on one side is incompatible with mode on on the other side.
Why this is correct
That is exactly why the channel does not negotiate properly.
Clue confirmation
The clue words "best", "never" in the question point toward this answer.
Related concept
EtherChannel bundles multiple physical switch ports into a single logical link to increase bandwidth and provide redundancy.
In a different scenario where the question specifies that both switches are configured to use PAgP, and one switch is set to 'desirable' mode while the other is set to 'auto', this option would be correct. The question would need to focus on PAgP specifically, rather than LACP.
✗
The interfaces must be configured as routed ports first.
Why it's wrong here
EtherChannel commonly bundles switch ports or trunks.
When this WOULD be correct
In a different scenario where the question specifies that the switches are intended to connect as routed ports for Layer 3 communication, and the exam asks about the prerequisites for establishing an EtherChannel in that context, this option would be correct.
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.
✓LACP active on one side is incompatible with mode on on the other side.Correct answer▾
Why this is correct
That is exactly why the channel does not negotiate properly.
✗The switches are using different native VLANs.Wrong answer — click to see why▾
Why this is wrong here
This option is wrong because different native VLANs do not prevent an EtherChannel from forming; they can still establish a link if other configurations are compatible. The primary issue in this scenario is related to LACP mode mismatches.
★ When this WOULD be the correct answer
In a different question, if the context involved troubleshooting a trunk link where the native VLANs on both switches were indeed mismatched, this option would be correct. For example, if the question specified that the EtherChannel was configured for trunking and the native VLANs were different, it could lead to a failure in establishing the trunk.
Why candidates choose this
Candidates may choose this option because they recall that native VLAN mismatches can cause issues in VLAN communication, leading them to mistakenly believe it would also affect EtherChannel formation.
✗Both sides must use PAgP desirable mode.Wrong answer — click to see why▾
Why this is wrong here
This option is incorrect because EtherChannel can use either PAgP or LACP for negotiation, and both protocols can operate independently of each other. The requirement for both sides to use PAgP in desirable mode is not a necessity for EtherChannel to function.
★ When this WOULD be the correct answer
In a different scenario where the question specifies that both switches are configured to use PAgP, and one switch is set to 'desirable' mode while the other is set to 'auto', this option would be correct. The question would need to focus on PAgP specifically, rather than LACP.
Why candidates choose this
Candidates may choose this option due to a common misconception that both ends of an EtherChannel must use the same protocol, leading them to believe that PAgP modes are strictly required for successful configuration.
✗The interfaces must be configured as routed ports first.Wrong answer — click to see why▾
Why this is wrong here
This option is wrong because EtherChannel can be configured on switch ports without needing to convert them to routed ports. Routed ports are not necessary for EtherChannel to function, as it operates at Layer 2.
★ When this WOULD be the correct answer
In a different scenario where the question specifies that the switches are intended to connect as routed ports for Layer 3 communication, and the exam asks about the prerequisites for establishing an EtherChannel in that context, this option would be correct.
Why candidates choose this
Candidates may find this option tempting because they might confuse EtherChannel configurations with routed port requirements, leading them to believe that all interfaces must be Layer 3 before forming a channel.
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
Ensure you match the correct protocol and mode on both sides of the link; mixing protocols or incompatible modes will prevent channel formation.
Detailed technical explanation
How to think about this question
EtherChannel technology allows multiple physical Ethernet links to be combined into one logical link, increasing bandwidth and providing redundancy between switches. Cisco supports three modes for EtherChannel formation: static mode 'on', LACP (Link Aggregation Control Protocol), and PAgP (Port Aggregation Protocol). LACP and PAgP are negotiation protocols that dynamically form the channel, while static mode 'on' forces the channel without negotiation. LACP is an IEEE standard and supports active and passive modes, where active mode actively initiates negotiation and passive mode responds to negotiation requests.
For EtherChannel to form successfully, both ends must use compatible protocols and modes. If one side is configured with LACP active mode, it expects the other side to be either LACP active or passive to negotiate the channel. If the other side uses static mode 'on', it does not participate in negotiation, causing the channel formation to fail. Similarly, PAgP modes must match on both sides for negotiation. Native VLAN mismatches or routed port configurations do not directly prevent EtherChannel formation but can cause other connectivity issues.
The exam trap here is confusing negotiation protocols and modes. Candidates often assume that any mode combination will form an EtherChannel, but mismatched protocols or static versus dynamic modes cause failure. Practically, network engineers must ensure both sides use the same EtherChannel protocol and compatible modes to avoid link bundling issues. This understanding is crucial for troubleshooting EtherChannel problems in Cisco networks and for passing the CCNA exam.
KKey Concepts to Remember
EtherChannel bundles multiple physical switch ports into a single logical link to increase bandwidth and provide redundancy.
LACP (Link Aggregation Control Protocol) requires both ends to be configured in compatible modes: either active or passive for negotiation.
Static EtherChannel mode 'on' forces the channel without negotiation and requires the other side to also use static mode 'on'.
PAgP (Port Aggregation Protocol) uses modes 'desirable' and 'auto' and is Cisco-proprietary, but is not mandatory for EtherChannel formation.
Native VLAN mismatches can cause trunking issues but do not prevent EtherChannel negotiation or formation directly.
EtherChannel does not support bundling routed ports; it only bundles switchports configured as access or trunk interfaces.
A mismatch between LACP active mode and static mode 'on' causes the EtherChannel bundle to fail to form due to incompatible negotiation methods.
Correct EtherChannel formation depends on matching protocols and modes on both sides to ensure proper negotiation and link bundling.
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
EtherChannel bundles multiple physical switch ports into a single logical link to increase bandwidth and provide redundancy.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 200-301 question in full detail.
Review etherChannel bundles multiple physical switch ports into a single logical link to increase bandwidth and provide redundancy., then practise related 200-301 questions on the same topic to reinforce the concept.
Network Services and Security — This question tests Network Services and Security — EtherChannel bundles multiple physical switch ports into a single logical link to increase bandwidth and provide redundancy..
What is the correct answer to this question?
The correct answer is: LACP active on one side is incompatible with mode on on the other side. — One side is using LACP active mode and the other side is forcing a static channel-group with mode on. Those modes are not compatible. LACP needs active or passive on both sides, while PAgP uses desirable or auto, and static mode on expects a manual bundle on the other side.
What should I do if I get this 200-301 question wrong?
Review etherChannel bundles multiple physical switch ports into a single logical link to increase bandwidth and provide redundancy., then practise related 200-301 questions on the same topic to reinforce the concept.
Are there clue words in this question I should notice?
Yes — watch for: "best", "never". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
EtherChannel bundles multiple physical switch ports into a single logical link to increase bandwidth and provide redundancy.
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