Courseiva
← 200-301
Full test
Switching and Network Access →mediumMultiple ChoiceObjective-mapped

CCNA Switching and Network Access Practice Question

Exhibit

SW1# show etherchannel summary
Group  Port-channel  Protocol    Ports
1      Po1(SD)         LACP      Gi1/0/1(I) Gi1/0/2(I)

SW1 interface range gi1/0/1-2
 channel-group 1 mode active

SW2 interface range gi1/0/1-2
 channel-group 1 mode on

An administrator configures an EtherChannel between SW1 and SW2. The port-channel interfaces are physically up, but the EtherChannel bundle fails to come up. On SW1, the channel-group is set to mode active; on SW2, it is set to mode on. What is the most likely cause?

⚠ Common exam trap

Ensure both sides of an EtherChannel are set to compatible modes; 'on' mode does not participate in LACP negotiation.

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 active while the other side is set to on

EtherChannel requires compatible modes: LACP active mode sends negotiation packets, while 'on' mode disables all negotiation, so the two sides cannot agree and the bundle stays down. Option A is wrong because switch priority values are used in STP root election, not EtherChannel formation. Option C is wrong because the native VLAN does not need to be VLAN 1; it only needs to match on both ends. Option D is wrong because all member interfaces in an EtherChannel must be in the same VLAN, not different ones.

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 switch priority values are mismatched

    Why it's wrong here

    Switch priority values influence Spanning Tree Protocol root bridge election and have no effect on whether an EtherChannel can negotiate. LACP uses system ID and port priority for determining the active side of the bundle, but mismatched system priorities do not stop LACP from establishing the channel—both switches can use different LACP priorities and still form a working port channel. Therefore, a priority mismatch is not the reason the bundle failed in this scenario.

    When this WOULD be correct

    In a question about why a specific switch becomes the root bridge in a spanning tree topology, mismatched switch priority values would be the correct answer. For example, if two switches have different bridge priorities, the lower priority switch becomes the root bridge.

  • ✓

    One side is using LACP active while the other side is set to on

    Why this is correct

    The EtherChannel fails because LACP active mode actively sends LACPDUs to negotiate a bundle, but the opposite side configured with mode on is a static EtherChannel that performs no dynamic negotiation. Since mode on ignores LACP advertisements, the negotiation handshake never completes, leaving both links in their default non-bundled state. To form the bundle, both sides must use either LACP active/passive or both be set to the same static on mode.

  • ✗

    The native VLAN must be VLAN 1 for EtherChannel to form

    Why it's wrong here

    EtherChannel does not mandate that the native VLAN be VLAN 1; it only requires that the native VLAN configuration be consistent on all bundled trunk interfaces. If both switches set the same non-VLAN 1 native VLAN, the EtherChannel can form and pass traffic correctly. Even access ports with no native VLAN concept can be bundled as long as their VLAN assignments match, so claiming VLAN 1 is a prerequisite is incorrect.

    When this WOULD be correct

    In a question where an EtherChannel fails to form and both sides are configured with mismatched native VLANs (e.g., one side native VLAN 1, the other native VLAN 10), the correct answer would be that the native VLAN must match for the bundle to come up.

  • ✗

    Gi1/0/2 cannot be bundled because interfaces must be in different VLANs

    Why it's wrong here

    EtherChannel requires all member interfaces to have identical Layer 2 attributes, including the same access VLAN or, for trunks, the same allowed VLAN list and native VLAN. Placing Gi1/0/2 in a different VLAN from the other bundled interface would violate the consistency check and prevent the port channel from forming. The correct requirement is that interfaces must be in the same VLAN, not different VLANs, so this statement is factually inverted.

    When this WOULD be correct

    This option would be correct in a question where an administrator tries to bundle interfaces that are in different VLANs (e.g., one access port in VLAN 10 and another in VLAN 20) without using trunking, and the EtherChannel fails to form because all member interfaces must share the same VLAN configuration.

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 active while the other side is set to onCorrect answer▾

Why this is correct

The EtherChannel fails because LACP active mode actively sends LACPDUs to negotiate a bundle, but the opposite side configured with mode on is a static EtherChannel that performs no dynamic negotiation. Since mode on ignores LACP advertisements, the negotiation handshake never completes, leaving both links in their default non-bundled state. To form the bundle, both sides must use either LACP active/passive or both be set to the same static on mode.

✗The switch priority values are mismatchedWrong answer — click to see why▾

Why this is wrong here

Switch priority values affect STP root bridge election, not EtherChannel formation. EtherChannel negotiation depends on the channel-group mode (LACP, PAgP, or on), not on switch priority.

★ When this WOULD be the correct answer

In a question about why a specific switch becomes the root bridge in a spanning tree topology, mismatched switch priority values would be the correct answer. For example, if two switches have different bridge priorities, the lower priority switch becomes the root bridge.

Why candidates choose this

Candidates may confuse the role of priority in STP with its role in EtherChannel, assuming that mismatched priorities could prevent link aggregation, similar to how they affect root bridge selection.

✗The native VLAN must be VLAN 1 for EtherChannel to formWrong answer — click to see why▾

Why this is wrong here

EtherChannel does not require native VLAN to be VLAN 1; it can form with any native VLAN as long as both sides match. The issue here is the LACP mode mismatch (active vs. on), not the native VLAN.

★ When this WOULD be the correct answer

In a question where an EtherChannel fails to form and both sides are configured with mismatched native VLANs (e.g., one side native VLAN 1, the other native VLAN 10), the correct answer would be that the native VLAN must match for the bundle to come up.

Why candidates choose this

Candidates may confuse EtherChannel requirements with trunking requirements, where native VLAN mismatch can cause issues, or they may recall that some older Cisco implementations required native VLAN 1 for certain features.

✗Gi1/0/2 cannot be bundled because interfaces must be in different VLANsWrong answer — click to see why▾

Why this is wrong here

EtherChannel does not require interfaces to be in different VLANs; in fact, all interfaces in a bundle must belong to the same VLAN or be configured as trunk ports with the same allowed VLAN list. Option D is incorrect because bundling interfaces in different VLANs would cause a mismatch.

★ When this WOULD be the correct answer

This option would be correct in a question where an administrator tries to bundle interfaces that are in different VLANs (e.g., one access port in VLAN 10 and another in VLAN 20) without using trunking, and the EtherChannel fails to form because all member interfaces must share the same VLAN configuration.

Why candidates choose this

Candidates may confuse EtherChannel requirements with other technologies like VLAN load balancing or assume that different VLANs are needed to avoid loops, not realizing that EtherChannel requires consistent VLAN membership across all bundled interfaces.

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?”

Visual reference

SW1 Root Bridge SW2 SW3 BLK DP DP RP RP STP blocks one link to prevent loops DP = Designated Port RP = Root Port BLK = Blocked

About these practice questions

This 200-301 question is part of Courseiva's 1,389-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →

How Courseiva writes practice questions · Editorial policy

JA

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.