CCNA Switching and Network Access Practice Question
Network Topology
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'.
⚠ Common exam trap
The exam trap is that candidates often focus only on speed/duplex mismatches and forget that VLAN allowed lists must also match. Additionally, they may assume that the Port-channel interface inherits settings from member ports, but in fact, the member ports must match the Port-channel configuration.
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).
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.
- ✗
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
Using speed 1000 and duplex full correctly aligns the physical parameters, but the allowed VLAN list of 10,20 is incomplete because Gi0/2 and the Port-channel interface are configured for trunking VLANs 10,20,30. In LACP EtherChannels, every member port must have an identical allowed VLAN list to the port-channel; if VLAN 30 is omitted from Gi0/1/Gi0/2, the switch will detect a VLAN membership mismatch and place the ports in a suspended/err-disabled state rather than bundling them. The missing VLAN 30 breaks the prerequisite that all physical ports inherit the exact same VLAN configuration as the logical port-channel.
- ✗
Configure both Gi0/1 and Gi0/2 with speed 1000, duplex full, and switchport mode access.
Why it's wrong here
Setting both interfaces to switchport mode access while the existing Port-channel interface is configured as a trunk (as evidenced by its allowed VLAN list 10,20,30) creates an operational mode mismatch. LACP requires each member port to have the same Layer 2 mode as the port-channel; an access port cannot carry multiple VLANs and would not be eligible to join a trunking EtherChannel. This configuration would prevent the channel from forming, and even if it did, only a single untagged VLAN would be supported, defeating the purpose of carrying VLANs 10, 20, and 30.
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?”
Visual reference
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Related to this question
Learn chapter
Configuring Switch Ports for Desktops, VoIP Phones, APs, IoT, and Virtualized Hosts
Key term
Switch
A switch is a networking device that connects devices on a local area network and uses MAC addresses to forward data only to the intended recipient.
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.