The answer is that only one VLAN will pass traffic correctly across the link, while all other VLAN traffic fails. This happens because an access port, by definition, belongs to a single VLAN and strips any 802.1Q tags from frames, so when a switchport connected to another switch is mistakenly configured as an access port instead of a trunk, it cannot carry the multiple VLANs required for inter-switch communication. On the CCNA 200-301 v2 exam, this scenario tests your understanding of the fundamental difference between access and trunk ports, often appearing as a troubleshooting question where the physical link remains up but traffic from only one VLAN succeeds—a common trap is assuming a working link means all VLANs are passing. To remember this, think of an access port as a single-lane road: it only lets one VLAN’s traffic through, while a trunk is a multi-lane highway for many VLANs.
CCNA Switching and Network Access Practice Question
This 200-301 practice question tests your understanding of switching and network access. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. A key principle to apply: an access port on a Cisco switch forwards traffic for only one VLAN and does not tag frames with VLAN identifiers.. 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.
A switchport connected to another switch is configured as an access port by mistake. Which symptom is most likely in a multi-VLAN design?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Only one VLAN is likely to pass correctly, while other VLAN traffic across the link fails
The most likely symptom is that only one VLAN’s traffic works correctly across the link while traffic for other VLANs fails. In plain language, an access port belongs to one VLAN in normal switching behavior. If an inter-switch link that should carry multiple VLANs is accidentally configured as an access port, the network loses the ability to transport the other VLANs.
The physical link may stay up, which can make the problem seem subtle, but the logical role of the port is wrong.
Key principle: An access port on a Cisco switch forwards traffic for only one VLAN and does not tag frames with VLAN identifiers.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Only one VLAN is likely to pass correctly, while other VLAN traffic across the link fails
Why this is correct
This is correct because an access port normally carries one VLAN rather than multiple VLANs.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
An access port on a Cisco switch forwards traffic for only one VLAN and does not tag frames with VLAN identifiers.
✗
The link negotiates as a trunk but drops all VLAN traffic
Why it's wrong here
This is wrong because an access-port mistake does not convert the link into a routed port.
When this WOULD be correct
In a scenario where a question asks about a switchport configured as a trunk port but experiencing issues, option B could be correct if the switch is misconfigured and the link is intended to route traffic for multiple VLANs. The question would need to imply that the port should have been a routed port but was incorrectly set up.
✗
The switch generates excessive broadcasts on all VLANs
Why it's wrong here
This is wrong because OSPF metrics are unrelated to this switchport mistake.
When this WOULD be correct
In a question about OSPF behavior during a network topology change, such as adding or removing interfaces, where the reset of OSPF metrics is a direct consequence of those changes, this option would be correct.
✗
The switch stops learning MAC addresses entirely
Why it's wrong here
This is wrong because the switch can still learn MAC addresses on an access port.
When this WOULD be correct
In a scenario where a switch is misconfigured to not allow any VLAN traffic due to a faulty configuration or hardware failure, a question could ask what happens to MAC address learning. In that case, if the switch is unable to process any traffic, it might stop learning MAC addresses altogether.
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.
✓Only one VLAN is likely to pass correctly, while other VLAN traffic across the link failsCorrect answer▾
Why this is correct
This is correct because an access port normally carries one VLAN rather than multiple VLANs.
✗The link negotiates as a trunk but drops all VLAN trafficWrong answer — click to see why▾
Why this is wrong here
An access port cannot negotiate trunking; it will never become a trunk, so it does not drop all VLAN traffic—it simply forwards only one VLAN's traffic.
★ When this WOULD be the correct answer
In a scenario where a question asks about a switchport configured as a trunk port but experiencing issues, option B could be correct if the switch is misconfigured and the link is intended to route traffic for multiple VLANs. The question would need to imply that the port should have been a routed port but was incorrectly set up.
Why candidates choose this
Candidates may find this option tempting because they might confuse access ports with routed ports, believing that misconfigurations could lead to automatic adjustments in port types, especially in complex multi-VLAN environments.
✗The switch generates excessive broadcasts on all VLANsWrong answer — click to see why▾
Why this is wrong here
An access port does not generate excessive broadcasts; broadcast storms are unrelated to an access/trunk misconfiguration.
★ When this WOULD be the correct answer
In a question about OSPF behavior during a network topology change, such as adding or removing interfaces, where the reset of OSPF metrics is a direct consequence of those changes, this option would be correct.
Why candidates choose this
Candidates may choose this option due to a misunderstanding of how Layer 2 configurations impact Layer 3 protocols, mistakenly believing that access port misconfigurations would affect OSPF metrics.
✗The switch stops learning MAC addresses entirelyWrong answer — click to see why▾
Why this is wrong here
This option is wrong because an access port will still learn MAC addresses for devices within the configured VLAN, but it will not learn MAC addresses for devices in other VLANs. Thus, the switch does not stop learning MAC addresses entirely.
★ When this WOULD be the correct answer
In a scenario where a switch is misconfigured to not allow any VLAN traffic due to a faulty configuration or hardware failure, a question could ask what happens to MAC address learning. In that case, if the switch is unable to process any traffic, it might stop learning MAC addresses altogether.
Why candidates choose this
Candidates might choose this option because they associate access ports with VLAN limitations and mistakenly believe that this would lead to a complete halt in MAC address learning, overlooking the fact that learning is still possible within the configured VLAN.
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: answer the scenario, not the keyword
Be cautious not to confuse physical link status with logical configuration issues. An access port will not drop the link but will restrict traffic to a single VLAN.
Detailed technical explanation
How to think about this question
In Cisco networking, a switchport configured as an access port carries traffic for only a single VLAN. This means that all frames entering or leaving that port are tagged or untagged as belonging to one VLAN only. In contrast, trunk ports are designed to carry traffic for multiple VLANs simultaneously by tagging frames with VLAN identifiers using protocols like IEEE 802.1Q. This fundamental difference is critical in multi-VLAN environments where inter-switch links must transport traffic for several VLANs to maintain network segmentation and communication.
When a link between two switches is mistakenly configured as an access port instead of a trunk port, only the VLAN assigned to that access port will pass traffic correctly. Traffic from other VLANs will not be forwarded across the link, causing communication failures for devices in those VLANs. The physical link remains operational, which can mislead network engineers into thinking the connection is healthy. However, logically, the port restricts traffic to a single VLAN, breaking the multi-VLAN design and causing partial network outages.
This misconfiguration is a common exam trap because the link appears up and active, but VLAN traffic is limited. Candidates might incorrectly assume that the link converts to a routed port or that routing protocols like OSPF are affected, which is not the case. Understanding the difference between access and trunk ports and their roles in VLAN traffic forwarding is essential for troubleshooting and designing Cisco networks that support multiple VLANs effectively.
KKey Concepts to Remember
An access port on a Cisco switch forwards traffic for only one VLAN and does not tag frames with VLAN identifiers.
A trunk port carries traffic for multiple VLANs by tagging frames with VLAN IDs using protocols like IEEE 802.1Q.
Inter-switch links in multi-VLAN environments must be configured as trunk ports to transport all VLAN traffic correctly.
Configuring an inter-switch link as an access port restricts traffic to a single VLAN, causing other VLANs' traffic to fail across the link.
The physical link status remains up on an access port misconfiguration, which can obscure the VLAN traffic failure.
Routing protocols such as OSPF are unaffected by switchport mode misconfigurations because they operate at Layer 3, not Layer 2.
Switches continue to learn MAC addresses on access ports, so MAC address learning does not stop due to this misconfiguration.
Exam candidates must distinguish between access and trunk port roles to avoid misinterpreting symptoms of VLAN traffic failures.
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.
Key takeaway
An access port on a Cisco switch forwards traffic for only one VLAN and does not tag frames with VLAN identifiers.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 200-301 question in full detail.
Review an access port on a Cisco switch forwards traffic for only one VLAN and does not tag frames with VLAN identifiers., then practise related 200-301 questions on the same topic to reinforce the concept.
Switching and Network Access — This question tests Switching and Network Access — An access port on a Cisco switch forwards traffic for only one VLAN and does not tag frames with VLAN identifiers..
What is the correct answer to this question?
The correct answer is: Only one VLAN is likely to pass correctly, while other VLAN traffic across the link fails — The most likely symptom is that only one VLAN’s traffic works correctly across the link while traffic for other VLANs fails. In plain language, an access port belongs to one VLAN in normal switching behavior. If an inter-switch link that should carry multiple VLANs is accidentally configured as an access port, the network loses the ability to transport the other VLANs.
The physical link may stay up, which can make the problem seem subtle, but the logical role of the port is wrong.
What should I do if I get this 200-301 question wrong?
Review an access port on a Cisco switch forwards traffic for only one VLAN and does not tag frames with VLAN identifiers., then practise related 200-301 questions on the same topic to reinforce the concept.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
An access port on a Cisco switch forwards traffic for only one VLAN and does not tag frames with VLAN identifiers.
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