CCNA Switching and Network Access Practice Question
Exhibit
SW1: interface range g1/0/1-2 channel-group 1 mode active SW2: interface range g1/0/1-2 channel-group 1 mode on
Exhibit: SW1 is configured for EtherChannel with LACP, but the bundle does not form. What is the most likely cause?
⚠ Common exam trap
Ensure both sides of the EtherChannel are set to negotiate with LACP; avoid static channel settings.
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
✓
One side is using LACP and the other side is using a static EtherChannel mode
For an LACP EtherChannel to form, both sides must negotiate with LACP using active or passive mode. One side here is set to channel-group mode on, which creates a static channel and does not speak LACP. That mismatch prevents the bundle from forming.
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 interfaces should use PAgP instead of LACP on both ends
Why it's wrong here
PAgP is a Cisco proprietary Port Aggregation Protocol, but using it is not a remedy here because LACP is an IEEE standard capable of forming the channel perfectly if both sides are configured for it. The actual problem is that one side is not speaking LACP at all, so switching to PAgP would still leave the same fundamental mismatch: one side would need to be in desirable or auto mode, and if the other remains static, the negotiation still fails. Thus, PAgP is neither required nor sufficient to resolve this failure.
When this WOULD be correct
In a different scenario where a question asks about a misconfiguration in an EtherChannel setup using PAgP, if both ends of the connection were configured for PAgP instead of LACP, then this option would be correct. For example, if a question stated that both ends were set to PAgP and the bundle failed to form, this would be a valid reason.
- ✓
One side is using LACP and the other side is using a static EtherChannel mode
Why this is correct
The correct explanation is that EtherChannel will not form because the interface configurations are incompatible: one side is running LACP in active mode, which sends LACP PDUs to negotiate a channel, while the other side is configured with a static mode (mode on), which does not send or process LACP PDUs. Without LACP negotiation from both peers, the switch sees no valid LACP partner and refuses to bundle the links. To fix this, both ends must use LACP (active/passive) or both must use static mode.
- ✗
The links must be routed ports before EtherChannel can form
Why it's wrong here
EtherChannel does not require routed ports; it can be formed on Layer 2 switchports configured as access or trunk ports, which is the typical scenario in a LAN switching environment. The exhibited configuration is presumably on Layer 2 interfaces, and the failure to bundle is unrelated to IP routing or L3 port characteristics. Therefore, converting the links to routed ports would not solve the issue.
When this WOULD be correct
If the question specified that the interfaces were configured as routed ports and required to form an EtherChannel, then this option would be correct. In that scenario, the exam would be testing knowledge on the prerequisites for EtherChannel formation specifically related to port types.
- ✗
EtherChannel requires three or more member links
Why it's wrong here
EtherChannel does not require three or more member links; two physical links are sufficient to form a single logical EtherChannel bundle, and the standard supports up to eight active links. The problem in the exhibit is a protocol negotiation mismatch, not a deficiency in link count. Adding more links would not overcome the fact that the interfaces cannot agree on an aggregation protocol.
When this WOULD be correct
In a different question context where the exam specifies that an EtherChannel configuration must include at least three links for proper operation, option D would be correct. For example, a question could state that a network engineer is attempting to configure an EtherChannel with only two links and is encountering issues.
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.
✓One side is using LACP and the other side is using a static EtherChannel modeCorrect answer▾
Why this is correct
The correct explanation is that EtherChannel will not form because the interface configurations are incompatible: one side is running LACP in active mode, which sends LACP PDUs to negotiate a channel, while the other side is configured with a static mode (mode on), which does not send or process LACP PDUs. Without LACP negotiation from both peers, the switch sees no valid LACP partner and refuses to bundle the links. To fix this, both ends must use LACP (active/passive) or both must use static mode.
✗The interfaces should use PAgP instead of LACP on both endsWrong answer — click to see why▾
Why this is wrong here
This option is incorrect because the question specifies that LACP is being used, which is incompatible with PAgP. EtherChannel can operate with either LACP or PAgP, but not both simultaneously.
★ When this WOULD be the correct answer
In a different scenario where a question asks about a misconfiguration in an EtherChannel setup using PAgP, if both ends of the connection were configured for PAgP instead of LACP, then this option would be correct. For example, if a question stated that both ends were set to PAgP and the bundle failed to form, this would be a valid reason.
Why candidates choose this
Candidates may be tempted by this option because they might confuse EtherChannel protocols and assume that if one protocol fails, another must be the solution, leading them to overlook the specific protocol in use.
✗The links must be routed ports before EtherChannel can formWrong answer — click to see why▾
Why this is wrong here
This option is wrong because EtherChannel can form with access ports or trunk ports, and there is no requirement for the interfaces to be routed ports for EtherChannel to function.
★ When this WOULD be the correct answer
If the question specified that the interfaces were configured as routed ports and required to form an EtherChannel, then this option would be correct. In that scenario, the exam would be testing knowledge on the prerequisites for EtherChannel formation specifically related to port types.
Why candidates choose this
Candidates may choose this option due to a common misconception that EtherChannel only works with Layer 2 interfaces, leading them to incorrectly believe that routed ports are incompatible with EtherChannel configurations.
✗EtherChannel requires three or more member linksWrong answer — click to see why▾
Why this is wrong here
EtherChannel can function with as few as two member links; therefore, requiring three or more member links is not a valid reason for the bundle not forming in this scenario.
★ When this WOULD be the correct answer
In a different question context where the exam specifies that an EtherChannel configuration must include at least three links for proper operation, option D would be correct. For example, a question could state that a network engineer is attempting to configure an EtherChannel with only two links and is encountering issues.
Why candidates choose this
Candidates may be misled by the common belief that more links enhance redundancy and performance, leading them to think that a minimum number of links is required for EtherChannel to work.
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?”
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Key term
EtherChannel
EtherChannel is a technology that bundles multiple physical Ethernet links into a single logical link to increase bandwidth and provide redundancy.
Key term
Link Aggregation Control Protocol
Link Aggregation Control Protocol (LACP) is a standard protocol that automatically bundles multiple physical network links into a single logical link to increase bandwidth and provide redundancy.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.