Question 1,265 of 1,819
Switching and Network AccesshardTroubleshootingObjective-mapped

CCNA Switching and Network Access Practice Question

This 200-301 practice question tests your understanding of switching and network access. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. 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.

Network Topology
Gi0/1Gi0/1LACP EtherChannelSW1SW2

You are connected to Multilayer Switch SW1. Configure LACP EtherChannel between SW1 and SW2 using ports GigabitEthernet0/1 and GigabitEthernet0/2. Ensure the channel is formed and active. The current configuration has mismatched VLAN assignments and speed/duplex settings preventing the channel from coming up. Verify the channel state using 'show etherchannel summary'.

Question 1hardTroubleshooting
Open the full VLAN trunking answer →
Network Topology
+SW1#show running-config | section interfaceinterface GigabitEthernet0/1switchport mode trunkswitchport trunk allowed vlan 10,20speed 1000duplex fullchannel-group 1 mode activeinterface GigabitEthernet0/2switchport trunk allowed vlan 30speed 100duplex halfinterface Port-channel1switchport trunk allowed vlan 10,20,30SW2#show running-config | section interfaceSW1#show etherchannel summaryH - Hot-standby (LACP only)u - unsuitable for bundlingd - default portNumber of aggregators: 1Group Port-channel Protocol Ports1 Po1(SD) LACP Gi0/1(D) Gi0/2(D)

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

Configure both Gi0/1 and Gi0/2 with speed 1000, duplex full, and switchport trunk allowed vlan 10,20,30.

The EtherChannel is down because the two member ports on SW1 have inconsistent configurations. GigabitEthernet0/1 is set to speed 1000 and duplex full with allowed VLANs 10,20, while GigabitEthernet0/2 is set to speed 100 and duplex half with allowed VLAN 30. LACP requires all member ports to have identical speed, duplex, and VLAN allowed lists. To fix, on SW1 configure both Gi0/1 and Gi0/2 with the same speed (1000), duplex (full), and trunk allowed VLANs (10,20,30). The Port-channel interface already has the correct allowed VLANs. After correction, 'show etherchannel summary' should show both ports as bundled (P).

Key principle: A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Configure both Gi0/1 and Gi0/2 with speed 1000, duplex full, and switchport trunk allowed vlan 10,20,30.

    Why this is correct

    This is correct because LACP requires all member ports to have identical speed, duplex, and allowed VLAN lists. The existing Port-channel interface already has the correct allowed VLANs, so fixing the physical port inconsistencies will allow the channel to form.

    Related concept

    Access ports place end devices into a single VLAN.

  • Configure both Gi0/1 and Gi0/2 with speed 100, duplex half, and switchport trunk allowed vlan 30.

    Why it's wrong here

    This is incorrect because it sets speed and duplex to lower values that do not match the intended high-speed link, and the allowed VLAN list is limited to VLAN 30 only, which would not match the Port-channel interface's allowed VLANs (10,20,30).

  • Configure both Gi0/1 and Gi0/2 with speed 1000, duplex full, and switchport trunk allowed vlan 10,20.

    Why it's wrong here

    This is incorrect because the allowed VLAN list (10,20) does not include VLAN 30, which is present on Gi0/2 and likely on the Port-channel interface. LACP requires identical allowed VLANs on all member ports.

  • Configure both Gi0/1 and Gi0/2 with speed 1000, duplex full, and switchport mode access.

    Why it's wrong here

    This is incorrect because the Port-channel interface is likely configured as a trunk (given the allowed VLANs), and setting the member ports to access mode would create a mismatch, preventing the EtherChannel from forming.

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.

Configure both Gi0/1 and Gi0/2 with speed 1000, duplex full, and switchport trunk allowed vlan 10,20,30.Correct answer

Why this is correct

This is correct because LACP requires all member ports to have identical speed, duplex, and allowed VLAN lists. The existing Port-channel interface already has the correct allowed VLANs, so fixing the physical port inconsistencies will allow the channel to form.

Configure both Gi0/1 and Gi0/2 with speed 100, duplex half, and switchport trunk allowed vlan 30.Wrong answer — click to see why

Why this is wrong here

The specific factual error is that LACP requires all member ports to have identical configurations, and this option does not align with the existing Port-channel configuration.

Why candidates choose this

Candidates might pick this if they think matching the slower port's settings is acceptable, but LACP requires all ports to be identical and consistent with the Port-channel interface.

Configure both Gi0/1 and Gi0/2 with speed 1000, duplex full, and switchport trunk allowed vlan 10,20.Wrong answer — click to see why

Why this is wrong here

The specific factual error is that the VLAN allowed list must match across all member ports and the Port-channel interface; omitting VLAN 30 will cause inconsistency.

Why candidates choose this

Candidates might pick this if they think only the common VLANs are needed, but LACP requires exact match of allowed VLANs.

Configure both Gi0/1 and Gi0/2 with speed 1000, duplex full, and switchport mode access.Wrong answer — click to see why

Why this is wrong here

The specific factual error is that LACP requires consistent switchport mode (access or trunk) across all member ports and the Port-channel interface.

Why candidates choose this

Candidates might pick this if they confuse access mode with trunk mode or think that speed/duplex are the only requirements, ignoring the VLAN mode.

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: an active trunk can still block the VLAN you need

A trunk being up does not prove every VLAN is crossing it. Check allowed VLAN lists, native VLAN mismatch, VLAN existence and access-port assignment.

Detailed technical explanation

How to think about this question

VLAN questions usually combine access-port and trunking clues. The key is to identify whether the issue is local to one switchport, caused by the trunk, or caused by the VLAN not existing where it needs to exist.

KKey Concepts to Remember

  • Access ports place end devices into a single VLAN.
  • Trunk ports carry multiple VLANs between switches.
  • Allowed VLAN lists decide which VLANs can cross a trunk.
  • Native VLAN mismatch can create confusing symptoms.

TExam Day Tips

  • Use show vlan brief to verify access VLANs.
  • Use show interfaces trunk to verify trunk state and allowed VLANs.
  • Do not treat every same-VLAN issue as a routing problem.

Key takeaway

A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches.

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.

What to study next

Got this wrong? Here's your next step.

Review VLAN allowed lists, native VLAN mismatch detection, and how to verify VLAN membership with show vlan brief and show interfaces trunk. Then practise related 200-301 questions on switching, trunking, and access-port configuration.

Related practice questions

Related 200-301 practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

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FAQ

Questions learners often ask

What does this 200-301 question test?

Switching and Network Access — This question tests Switching and Network Access — Access ports place end devices into a single VLAN..

What is the correct answer to this question?

The correct answer is: Configure both Gi0/1 and Gi0/2 with speed 1000, duplex full, and switchport trunk allowed vlan 10,20,30. — The EtherChannel is down because the two member ports on SW1 have inconsistent configurations. GigabitEthernet0/1 is set to speed 1000 and duplex full with allowed VLANs 10,20, while GigabitEthernet0/2 is set to speed 100 and duplex half with allowed VLAN 30. LACP requires all member ports to have identical speed, duplex, and VLAN allowed lists. To fix, on SW1 configure both Gi0/1 and Gi0/2 with the same speed (1000), duplex (full), and trunk allowed VLANs (10,20,30). The Port-channel interface already has the correct allowed VLANs. After correction, 'show etherchannel summary' should show both ports as bundled (P).

What should I do if I get this 200-301 question wrong?

Review VLAN allowed lists, native VLAN mismatch detection, and how to verify VLAN membership with show vlan brief and show interfaces trunk. Then practise related 200-301 questions on switching, trunking, and access-port configuration.

What is the key concept behind this question?

Access ports place end devices into a single VLAN.

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Last reviewed: Jun 6, 2026

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