Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
A switch port connected to a user PC is configured as a trunk. The PC cannot communicate normally. What is the best explanation?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
The port role is wrong because a normal PC-facing switchport should usually be an access port, not a trunk
This is correct because a standard PC is normally connected to an access port in one VLAN.
B
Distractor review
A user PC requires EtherChannel to function
This is wrong because a normal user PC does not require EtherChannel for ordinary connectivity.
C
Distractor review
Trunk mode disables MAC address learning automatically
This is wrong because trunking does not disable MAC learning by itself.
D
Distractor review
Trunk mode forces the switch to stop using IP addressing
This is wrong because trunk mode does not disable IP functions on the switch.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is assuming that configuring a switch port as a trunk is always correct or beneficial, even for user PCs. Candidates may think trunking provides better segmentation or security, but user devices do not process VLAN tags. This mismatch causes the PC to drop or ignore tagged frames, leading to communication failure. The trap is confusing trunk ports with access ports and not recognizing that trunk ports are intended for switch-to-switch or switch-to-router links carrying multiple VLANs, not end-user devices.
Technical deep dive
How to think about this question
A switch port configured as a trunk is designed to carry traffic for multiple VLANs by tagging frames with VLAN identifiers using the IEEE 802.1Q standard. This allows switches to segregate traffic logically across the same physical link. However, end-user devices like PCs typically do not understand VLAN tagging and expect to send and receive untagged Ethernet frames. Therefore, the standard practice is to configure switch ports connected to user PCs as access ports, which carry traffic for a single VLAN without tagging frames. The decision to configure a port as access or trunk depends on the connected device type and network design. Access ports are assigned to a single VLAN and forward untagged frames, making them suitable for user devices. Trunk ports, on the other hand, carry multiple VLANs and tag frames accordingly. When a PC-facing port is mistakenly set as a trunk, the PC receives tagged frames it cannot interpret, causing communication failures. The switch still learns MAC addresses on trunk ports, but the VLAN tagging mismatch prevents normal PC communication. This scenario is a common exam trap where candidates confuse trunk and access port roles. The trap lies in assuming trunk mode is always beneficial or required, but it is inappropriate for user endpoints. Practically, a trunk port connected to a PC will cause connectivity issues because the PC does not process VLAN tags. Correct network design mandates that edge ports connected to end devices be access ports to ensure proper VLAN membership and seamless communication.
KKey Concepts to Remember
- A switch port connected to a user PC is typically configured as an access port to carry traffic for a single VLAN without tagging frames.
- Trunk ports are designed to carry traffic for multiple VLANs simultaneously by tagging Ethernet frames with VLAN identifiers using IEEE 802.1Q.
- A user PC normally sends and receives untagged Ethernet frames and does not understand VLAN tagging, so it requires an access port configuration.
- Configuring a PC-facing port as a trunk causes a mismatch because the PC cannot process tagged frames, leading to communication failures.
- Switch ports in trunk mode still learn MAC addresses and forward frames normally but expect VLAN tags, which user PCs do not generate.
- EtherChannel is a link aggregation technology that combines multiple physical links into one logical link and is not required for basic PC connectivity.
- Trunk mode does not disable IP addressing or MAC address learning on the switch; it only changes how VLAN tags are handled on the port.
- Proper VLAN design requires edge ports connected to end devices to be access ports to ensure correct VLAN membership and frame handling.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
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Question 2
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Question 3
What is the OSPF metric called?
Question 4
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Question 5
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Question 6
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FAQ
Questions learners often ask
What does this 200-301 question test?
A switch port connected to a user PC is typically configured as an access port to carry traffic for a single VLAN without tagging frames.
What is the correct answer to this question?
The correct answer is: The port role is wrong because a normal PC-facing switchport should usually be an access port, not a trunk — A user-facing PC port is normally expected to be an access port, not a trunk. In plain language, the PC usually sends ordinary untagged Ethernet frames and does not expect to participate in multi-VLAN trunk behavior. If the switch port is configured as a trunk, the logical design no longer matches the endpoint’s normal behavior, which can lead to failed or inconsistent communication. This is a classic edge-port design error. The physical link may come up, but the role of the port is wrong for the device type attached. The correct answer is the one that recognizes the mismatch between trunk behavior and a normal user host connection.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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