Question 244 of 1,389
CCNA Switching and Network Access Practice Question
An EtherChannel between SW1 and SW2 is not forming. The technician runs the show etherchannel summary command on both switches and sees that all configured interfaces are in the 'I' (stand-alone) state. Both switches have their interfaces configured with channel-group 1 mode active. What should the technician check next?
⚠ Common exam trap
Cisco often tests the misconception that the 'I' (stand-alone) state always indicates a physical or protocol mismatch, when in fact it frequently points to Layer 2 configuration inconsistencies like VLAN mismatches that prevent LACP from completing 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
✓
Check for a VLAN mismatch on the member interfaces (e.g., mismatched native VLAN or allowed VLAN list).
When both switches are configured with channel-group 1 mode active, they are using LACP (active/active). The 'I' (stand-alone) state indicates the ports are not forming an EtherChannel despite LACP being enabled. A VLAN mismatch—such as differing native VLANs or allowed VLAN lists—can prevent LACP from successfully negotiating the bundle, as the control plane sees a Layer 2 inconsistency and keeps the ports in stand-alone mode.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Verify that both switches are using the same EtherChannel protocol (LACP or PAgP).
Why it's wrong here
Because both switches were configured with `channel-group 1 mode active`, they are already using LACP unambiguously — `active` is an LACP-specific mode, not a PAgP mode. If the neighboring switch had been set to PAgP, LACPDUs would fail and the ports would remain in the stand-alone 'I' state, but inspecting the protocol now would only confirm what the configuration already proves. A protocol mismatch is not the issue here, since both sides explicitly negotiated LACP; the correct diagnostic path is to check VLAN consistency, which directly affects whether LACP considers the member links eligible for bundling.
- ✗
Check that the speed and duplex settings match on all member interfaces.
Why it's wrong here
While speed/duplex mismatch is a valid cause of the 'I' state, it is not the most targeted next step after confirming LACP mode. The technician should first rule out VLAN configuration mismatches, which are equally likely and require immediate inspection when trunk ports are involved.
- ✓
Check for a VLAN mismatch on the member interfaces (e.g., mismatched native VLAN or allowed VLAN list).
Why this is correct
LACP requires that all member ports have identical VLAN configurations (switchport mode, allowed VLANs, native VLAN). A mismatch in any of these parameters keeps the ports in stand-alone state. Since the protocol is already confirmed as LACP, verifying VLAN consistency is the most appropriate next step.
- ✗
Determine whether Spanning Tree Protocol is blocking one of the ports.
Why it's wrong here
STP blocking state does not affect EtherChannel negotiation. A port that is part of a bundle will be shown in the 'P' (bundled) state regardless of STP status. The 'I' state indicates the port is not even joining the bundle, so STP is not the cause.
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.
✓Check for a VLAN mismatch on the member interfaces (e.g., mismatched native VLAN or allowed VLAN list).Correct answer▾
Why this is correct
LACP requires that all member ports have identical VLAN configurations (switchport mode, allowed VLANs, native VLAN). A mismatch in any of these parameters keeps the ports in stand-alone state. Since the protocol is already confirmed as LACP, verifying VLAN consistency is the most appropriate next step.
✗Verify that both switches are using the same EtherChannel protocol (LACP or PAgP).Wrong answer — click to see why▾
Why this is wrong here
Assuming that a protocol mismatch might exist without checking the existing configuration first.
✗Check that the speed and duplex settings match on all member interfaces.Wrong answer — click to see why▾
Why this is wrong here
Prioritizing a Layer 1 check over a Layer 2 parameter that must be identical for EtherChannel to bundle.
✗Determine whether Spanning Tree Protocol is blocking one of the ports.Wrong answer — click to see why▾
Why this is wrong here
Confusing STP port states with EtherChannel negotiation states.
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
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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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