- A
Enhanced security through network segmentation
VLANs isolate traffic between groups.
- B
Eliminates the need for routing
Why wrong: Inter-VLAN communication still requires routing.
- C
Increased collision domains
Why wrong: Switches already eliminate collisions; VLANs do not increase them.
- D
Reduction of broadcast traffic
Broadcasts are confined to each VLAN.
- E
Simplified network administration when users move
Users can be reassigned to different VLANs without rewiring.
Question 147 of 1,000
ISC2 CC Network Security Practice Question
This CC practice question tests your understanding of network security. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
Which three of the following are benefits of using VLANs in a network? (Choose three.)
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
✓
Enhanced security through network segmentation
VLANs improve security through segmentation, reduce broadcast traffic, and simplify network changes. They do not increase collision domains (switches eliminate collisions) and do not replace routing.
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.
- ✓
Enhanced security through network segmentation
Why this is correct
VLANs isolate traffic between groups.
Related concept
Access ports place end devices into a single VLAN.
- ✗
Eliminates the need for routing
Why it's wrong here
Inter-VLAN communication still requires routing.
- ✗
Increased collision domains
Why it's wrong here
Switches already eliminate collisions; VLANs do not increase them.
- ✓
Reduction of broadcast traffic
- ✓
Simplified network administration when users move
Why this is correct
Users can be reassigned to different VLANs without rewiring.
Related concept
Access ports place end devices into a single VLAN.
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 security analyst at a medium-sized enterprise encounters this scenario during an investigation or architecture review. The correct answer reflects best practice for the specific threat or control described. 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. Security exam questions test whether you can match controls to threats in context — not just recall definitions.
Visual reference
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 CC questions on switching, trunking, and access-port configuration.
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FAQ
Questions learners often ask
What does this CC question test?
Network Security — This question tests Network Security — Access ports place end devices into a single VLAN..
What is the correct answer to this question?
The correct answer is: Enhanced security through network segmentation — VLANs improve security through segmentation, reduce broadcast traffic, and simplify network changes. They do not increase collision domains (switches eliminate collisions) and do not replace routing.
What should I do if I get this CC 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 CC 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: Jul 4, 2026
This CC practice question is part of Courseiva's free ISC2 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 CC exam.
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