CCNA Switching and Network Access Practice Question
Network Topology
You are connected to SW1. Configure an LACP EtherChannel between SW1 and SW2 using ports GigabitEthernet0/1 and GigabitEthernet0/2. Set the channel-group mode to active on both sides. The port-channel interface should be configured as a trunk allowing VLANs 10, 20, and 30. Initially, the EtherChannel fails to form due to mismatched speed/duplex on one link. Identify and correct the issue, then verify the channel is up and operational.
⚠ Common exam trap
Do not confuse Layer 1 issues (speed/duplex) with Layer 2 configuration (VLANs, trunking) or LACP mode settings. Always check physical parameters first when an EtherChannel fails to form.
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
✓
Change speed and duplex on Gi0/2 to 1000 and full, then verify with 'show etherchannel summary'.
The EtherChannel fails because GigabitEthernet0/2 has speed 100 and duplex half, while GigabitEthernet0/1 has speed 1000 and duplex full. LACP requires all member ports to have identical speed and duplex settings. To resolve, change the speed and duplex on Gi0/2 to match Gi0/1: 'speed 1000' and 'duplex full'. After correction, the channel will bundle. Verify with 'show etherchannel summary' to see both ports in the 'P' (bundled) state.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Change speed and duplex on Gi0/2 to 1000 and full, then verify with 'show etherchannel summary'.
Why this is correct
This is correct because LACP requires all member ports to have identical speed and duplex settings. Gi0/2 had speed 100 and duplex half, while Gi0/1 had speed 1000 and duplex full. Changing Gi0/2 to match resolves the mismatch, allowing the EtherChannel to bundle. Verification with 'show etherchannel summary' shows both ports in the 'P' (bundled) state.
- ✗
Change the channel-group mode on Gi0/2 to passive, then verify with 'show etherchannel summary'.
Why it's wrong here
This is incorrect because the mode mismatch (active vs passive) is not the issue here; both sides are already set to active. Changing Gi0/2 to passive would create a mode mismatch, preventing the channel from forming. The actual problem is speed/duplex mismatch.
- ✗
Change the allowed VLANs on the port-channel to include only VLAN 1, then verify with 'show etherchannel summary'.
Why it's wrong here
In this scenario, Gi0/2's Layer 1 parameters—speed 100 and duplex half—are inconsistent with Gi0/1's 1000/full settings, which is the actual cause of the EtherChannel failing to bundle. LACP's negotiation process relies on those physical characteristics; VLAN configuration, such as the allowed VLAN list, is not part of the bundle decision and only affects how traffic is forwarded after the channel is up. Restricting the allowed VLANs to only VLAN 1 would leave the speed/duplex mismatch unresolved, so 'show etherchannel summary' would still show Gi0/2 in the 'I' (individual) state rather than 'P' (bundled). Therefore, the physical mismatch must be corrected first to satisfy LACP's compatibility checks.
- ✗
Change the port-channel interface to access mode, then verify with 'show etherchannel summary'.
Why it's wrong here
Changing the port-channel interface to access mode applies a logical switchport configuration and does not modify the physical properties of the member ports, so it cannot resolve the speed/duplex mismatch on Gi0/2 (100/half vs. Gi0/1's 1000/full). Although switchport mode is a compatibility parameter EthernetChannel checks alongside speed and duplex, the root cause here is a Layer 1 inconsistency—the link is physically incapable of running at the higher speed. LACP will continue to hold Gi0/2 in an individual state because the underlying physical parameters remain mismatched, even if the logical interface is switched to access mode. The 'show etherchannel summary' output would still not show both ports bundled, confirming that the access-mode change fails to address the real issue.
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.
✓Change speed and duplex on Gi0/2 to 1000 and full, then verify with 'show etherchannel summary'.Correct answer▾
Why this is correct
This is correct because LACP requires all member ports to have identical speed and duplex settings. Gi0/2 had speed 100 and duplex half, while Gi0/1 had speed 1000 and duplex full. Changing Gi0/2 to match resolves the mismatch, allowing the EtherChannel to bundle. Verification with 'show etherchannel summary' shows both ports in the 'P' (bundled) state.
✗Change the channel-group mode on Gi0/2 to passive, then verify with 'show etherchannel summary'.Wrong answer — click to see why▾
Why this is wrong here
The specific factual error is that LACP modes must be compatible (active-active or active-passive), but the question states both sides are active, so mode is not the issue.
Why candidates choose this
Candidates might think that LACP mode mismatch is the cause, especially if they recall that one side must be active and the other passive in some configurations.
✗Change the allowed VLANs on the port-channel to include only VLAN 1, then verify with 'show etherchannel summary'.Wrong answer — click to see why▾
Why this is wrong here
The specific factual error is that VLAN settings are irrelevant to the physical bundling of ports in an EtherChannel.
Why candidates choose this
Candidates might confuse trunk configuration requirements with EtherChannel prerequisites, thinking that VLAN mismatches can prevent channel formation.
✗Change the port-channel interface to access mode, then verify with 'show etherchannel summary'.Wrong answer — click to see why▾
Why this is wrong here
The specific factual error is that interface mode is a Layer 2 property unrelated to the physical bundling process.
Why candidates choose this
Candidates might think that trunk mode requires additional configuration that could cause issues, or they might confuse the port-channel interface configuration with the physical port settings.
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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Related to this question
Learn chapter
Configuring Switch Ports for Desktops, VoIP Phones, APs, IoT, and Virtualized Hosts
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.
Key term
EtherChannel
EtherChannel is a technology that bundles multiple physical Ethernet 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.