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: a VLAN must be explicitly created and active on a switch for that switch to forward traffic within that VLAN.. 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.
Exhibit
SW1# show vlan brief
60 Users-60 active
SW2# show vlan brief
10 Users-10 active
20 Users-20 active
SW2# show interfaces trunk
Port Mode Encapsulation Status Native vlan
Gi0/1 on 802.1q trunking 1
Port Vlans allowed on trunk
Gi0/1 10,20,60
Users in VLAN 60 on switch SW2 cannot reach the default gateway located on switch SW1. The trunk between SW1 and SW2 is operational and allows VLAN 60. What is the most likely reason for this issue?
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.
SW1# show vlan brief
60 Users-60 active
SW2# show vlan brief
10 Users-10 active
20 Users-20 active
SW2# show interfaces trunk
Port Mode Encapsulation Status Native vlan
Gi0/1 on 802.1q trunking 1
Port Vlans allowed on trunk
Gi0/1 10,20,60
A
VLAN 60 does not exist locally on SW2.
This is correct because trunk allowance alone is not enough if the VLAN is missing from the local switch.
B
The native VLAN must be changed to 60 on both switches.
Why wrong: This is wrong because the issue is local VLAN existence, not native VLAN choice.
C
VLAN 60 is not allowed on the trunk link.
Why wrong: This is wrong because PPP is unrelated to 802.1Q VLAN forwarding.
D
The default gateway must be configured as a loopback on SW2.
Why wrong: This is wrong because the problem is VLAN handling, not loopback gateway design.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
VLAN 60 does not exist locally on SW2.
VLAN 60 has not been created locally on SW2, even though the trunk can carry its traffic. A switch never processes VLAN traffic for a VLAN it doesn't know about; it discards tagged frames from the trunk destined for that VLAN and prevents access ports from assigning frames to it. (A) is correct. (B) is incorrect because native VLAN configuration only affects untagged frames—changing it to 60 is unnecessary for tagged VLAN 60 traffic. (C) is incorrect because the trunk is already configured to allow VLAN 60, so trunk filtering isn't the problem. (D) is incorrect because a default gateway is simply an IP address on a router or Layer 3 switch interface (like SVIs) and does not require a loopback on SW2.
Key principle: A VLAN must be explicitly created and active on a switch for that switch to forward traffic within that VLAN.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
VLAN 60 does not exist locally on SW2.
Why this is correct
This is correct because trunk allowance alone is not enough if the VLAN is missing from the local switch.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
A VLAN must be explicitly created and active on a switch for that switch to forward traffic within that VLAN.
✗
The native VLAN must be changed to 60 on both switches.
Why it's wrong here
This is wrong because the issue is local VLAN existence, not native VLAN choice.
When this WOULD be correct
In a different scenario where the question asks about VLAN configuration issues related to untagged traffic, changing the native VLAN to 60 could be necessary to ensure that devices on VLAN 60 can communicate properly with devices on other VLANs that are also configured to use the same native VLAN.
✗
VLAN 60 is not allowed on the trunk link.
Why it's wrong here
This is wrong because PPP is unrelated to 802.1Q VLAN forwarding.
When this WOULD be correct
In a different scenario, if the question specified that only PPP encapsulation is allowed for VLANs on a trunk link, then this option could be correct. For example, if the question stated that VLANs are only operational when PPP is configured on the trunk, then this option would apply.
✗
The default gateway must be configured as a loopback on SW2.
Why it's wrong here
This is wrong because the problem is VLAN handling, not loopback gateway design.
When this WOULD be correct
In a different scenario where the question specifies that the network design requires the default gateway to be a loopback interface for redundancy or routing purposes, this option could be correct. For instance, if the exam question states that SW2 must use a loopback interface for routing protocols, then this option would be valid.
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.
✓VLAN 60 does not exist locally on SW2.Correct answer▾
Why this is correct
This is correct because trunk allowance alone is not enough if the VLAN is missing from the local switch.
✗The native VLAN must be changed to 60 on both switches.Wrong answer — click to see why▾
Why this is wrong here
The native VLAN is used for untagged traffic on a trunk and is typically VLAN 1 by default. Changing the native VLAN to 60 would not resolve the issue because the problem is that VLAN 60 does not exist on SW2, not that the native VLAN is mismatched. Native VLAN mismatch can cause connectivity issues but is unrelated to the absence of the VLAN.
★ When this WOULD be the correct answer
In a different scenario where the question asks about VLAN configuration issues related to untagged traffic, changing the native VLAN to 60 could be necessary to ensure that devices on VLAN 60 can communicate properly with devices on other VLANs that are also configured to use the same native VLAN.
Why candidates choose this
Students often confuse the native VLAN with the VLAN that carries user traffic. They might think that setting the native VLAN to 60 would allow VLAN 60 traffic to pass, but native VLAN is only for untagged frames and does not affect tagged VLAN forwarding.
✗VLAN 60 is not allowed on the trunk link.Wrong answer — click to see why▾
Why this is wrong here
The trunk is specifically configured to allow VLAN 60, so this cannot be the cause.
★ When this WOULD be the correct answer
In a different scenario, if the question specified that only PPP encapsulation is allowed for VLANs on a trunk link, then this option could be correct. For example, if the question stated that VLANs are only operational when PPP is configured on the trunk, then this option would apply.
Why candidates choose this
Test-takers might confuse PPP with a protocol that can carry multiple VLANs, but PPP is a layer 2 protocol for point-to-point links and does not support VLANs. The mention of 'PPP' might be mistaken for 'P' in '802.1Q' or a similar acronym.
✗The default gateway must be configured as a loopback on SW2.Wrong answer — click to see why▾
Why this is wrong here
The default gateway is typically configured on a router or Layer 3 switch, not as a loopback interface on the access switch. A loopback interface is a virtual interface used for management or routing protocol stability, not for providing a default gateway to hosts. The issue is VLAN existence, not gateway design.
★ When this WOULD be the correct answer
In a different scenario where the question specifies that the network design requires the default gateway to be a loopback interface for redundancy or routing purposes, this option could be correct. For instance, if the exam question states that SW2 must use a loopback interface for routing protocols, then this option would be valid.
Why candidates choose this
Students might think that a loopback interface can serve as a default gateway because it is always up. However, the default gateway must be on the same subnet as the hosts and reachable via the VLAN. Configuring a loopback on SW2 would not provide connectivity to SW1's gateway.
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
Don't assume trunk configuration alone resolves VLAN issues; ensure VLANs exist on all relevant switches.
Detailed technical explanation
How to think about this question
VLANs (Virtual Local Area Networks) segment a physical network into multiple logical broadcast domains, allowing devices to communicate as if they were on separate physical networks. Each VLAN must be explicitly created on a switch to define its broadcast domain and associated Layer 2 forwarding behavior. When a switch receives traffic tagged with a VLAN ID, it forwards the frame only if that VLAN exists locally; otherwise, the traffic is dropped or ignored.
In Cisco switching environments, trunk links carry multiple VLANs between switches using 802.1Q tagging. However, simply allowing a VLAN on a trunk does not guarantee connectivity. The VLAN must be configured and active on both ends of the trunk. If a VLAN is missing on a switch, access ports assigned to that VLAN cannot forward traffic properly, and devices in that VLAN cannot reach their default gateway or other network resources.
The exam trap here is focusing solely on trunk configuration and native VLAN settings while overlooking the necessity of local VLAN creation. Even if the trunk allows VLAN 60, if SW2 does not have VLAN 60 defined, devices assigned to VLAN 60 on SW2 cannot communicate beyond their local switch. This practical issue often arises in campus networks where VLAN databases are not synchronized, causing connectivity failures despite correct trunk configurations.
KKey Concepts to Remember
A VLAN must be explicitly created and active on a switch for that switch to forward traffic within that VLAN.
Trunk links carry multiple VLANs using 802.1Q tagging but do not create VLANs on switches automatically.
Access ports assign devices to VLANs that must exist locally on the switch to forward traffic correctly.
If a VLAN is missing on a switch, traffic tagged for that VLAN is dropped or ignored on that switch.
Native VLAN mismatches affect untagged traffic but do not replace the need for VLAN creation on each switch.
PPP is unrelated to VLAN forwarding and does not affect 802.1Q trunk VLAN traffic.
Default gateways for VLANs are typically configured on Layer 3 devices or SVIs, not as loopbacks on access switches.
Network engineers must synchronize VLAN databases across switches to ensure consistent VLAN forwarding and connectivity.
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
A VLAN must be explicitly created and active on a switch for that switch to forward traffic within that VLAN.
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 a VLAN must be explicitly created and active on a switch for that switch to forward traffic within that VLAN., 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 — A VLAN must be explicitly created and active on a switch for that switch to forward traffic within that VLAN..
What is the correct answer to this question?
The correct answer is: VLAN 60 does not exist locally on SW2. — VLAN 60 has not been created locally on SW2, even though the trunk can carry its traffic. A switch never processes VLAN traffic for a VLAN it doesn't know about; it discards tagged frames from the trunk destined for that VLAN and prevents access ports from assigning frames to it. (A) is correct. (B) is incorrect because native VLAN configuration only affects untagged frames—changing it to 60 is unnecessary for tagged VLAN 60 traffic. (C) is incorrect because the trunk is already configured to allow VLAN 60, so trunk filtering isn't the problem. (D) is incorrect because a default gateway is simply an IP address on a router or Layer 3 switch interface (like SVIs) and does not require a loopback on SW2.
What should I do if I get this 200-301 question wrong?
Review a VLAN must be explicitly created and active on a switch for that switch to forward traffic within that VLAN., 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?
A VLAN must be explicitly created and active on a switch for that switch to forward traffic within that VLAN.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.