- A
Subnetting
Why wrong: Subnetting creates broadcast domains but requires a router or Layer 3 switch, not just a switch.
- B
VLANs
VLANs allow a single switch to support multiple broadcast domains, each isolated at Layer 2.
- C
VPN
Why wrong: VPNs provide encrypted tunnels over public networks, not broadcast domain segmentation.
- D
NAT
Why wrong: NAT translates IP addresses but does not segment broadcast domains.
Question 273 of 520
How VLANs Segment a LAN into Multiple Broadcast Domains
This N10-009 practice question tests your understanding of networking concepts. 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.
A network engineer wants to segment a LAN into multiple broadcast domains without purchasing additional hardware. Which of the following technologies should be implemented?
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
✓
VLANs
VLANs (Virtual Local Area Networks) allow a network engineer to logically segment a single physical LAN switch into multiple isolated broadcast domains without purchasing additional hardware. By assigning switch ports to different VLAN IDs, broadcast traffic is confined to ports within the same VLAN, effectively creating separate Layer 2 networks on the same switch infrastructure.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Subnetting
Why it's wrong here
Subnetting creates broadcast domains but requires a router or Layer 3 switch, not just a switch.
When this WOULD be correct
A network engineer wants to logically divide a single IP network into smaller subnetworks to improve IP address utilization and reduce broadcast traffic, but the switch does not support VLANs. In this case, subnetting with a router would be the correct answer.
- ✓
VLANs
Why this is correct
VLANs allow a single switch to support multiple broadcast domains, each isolated at Layer 2.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
VPN
Why it's wrong here
VPNs provide encrypted tunnels over public networks, not broadcast domain segmentation.
When this WOULD be correct
A company needs to securely connect remote branch offices over the internet. Which technology should be implemented? VPN would be correct as it provides encrypted connectivity over public infrastructure.
- ✗
NAT
Why it's wrong here
NAT translates IP addresses but does not segment broadcast domains.
When this WOULD be correct
A question asking: 'A company has run out of public IP addresses and needs to allow multiple internal hosts to share a single public IP when accessing the internet. Which technology should be implemented?' would make NAT the correct answer.
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 N10-009 exam frequently reuses these exact scenarios with slightly different constraints.
✓VLANsCorrect answer▾
Why this is correct
VLANs allow a single switch to support multiple broadcast domains, each isolated at Layer 2.
✗SubnettingWrong answer — click to see why▾
Why this is wrong here
Subnetting segments a network into multiple IP subnets, but it requires a router to forward traffic between subnets, and it does not create separate broadcast domains without additional hardware (the router). VLANs achieve broadcast domain segmentation at Layer 2 without extra hardware.
★ When this WOULD be the correct answer
A network engineer wants to logically divide a single IP network into smaller subnetworks to improve IP address utilization and reduce broadcast traffic, but the switch does not support VLANs. In this case, subnetting with a router would be the correct answer.
Why candidates choose this
Candidates often confuse subnetting with VLANs because both can reduce broadcast domains, but they forget that subnetting requires a Layer 3 device to separate broadcast domains, whereas VLANs operate at Layer 2 without additional hardware.
✗VPNWrong answer — click to see why▾
Why this is wrong here
VPNs create encrypted tunnels over public networks for secure remote access, but they do not segment a LAN into multiple broadcast domains; they operate at Layer 3 and above, not at Layer 2 where broadcast domains are defined.
★ When this WOULD be the correct answer
A company needs to securely connect remote branch offices over the internet. Which technology should be implemented? VPN would be correct as it provides encrypted connectivity over public infrastructure.
Why candidates choose this
Candidates may confuse VPN with VLAN due to similar acronyms, or mistakenly think VPN can isolate traffic within a LAN, not realizing VPNs are for secure remote connections, not local segmentation.
✗NATWrong answer — click to see why▾
Why this is wrong here
NAT (Network Address Translation) translates private IP addresses to public ones for internet access, but it does not segment a LAN into multiple broadcast domains. Broadcast domains are separated by Layer 2 or Layer 3 boundaries, not by address translation.
★ When this WOULD be the correct answer
A question asking: 'A company has run out of public IP addresses and needs to allow multiple internal hosts to share a single public IP when accessing the internet. Which technology should be implemented?' would make NAT the correct answer.
Why candidates choose this
Candidates may confuse NAT with network segmentation because both involve IP address manipulation, or they might think NAT creates separate networks by hiding internal addresses, but it does not affect broadcast domains.
Analysis generated from the official N10-009blueprint 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
CompTIA often tests the misconception that subnetting alone can segment broadcast domains, but subnetting only divides IP address space; without VLANs, all devices on the same switch remain in one broadcast domain at Layer 2.
Detailed technical explanation
How to think about this question
VLANs use 802.1Q trunking to tag Ethernet frames with a 12-bit VLAN ID (0–4095), allowing multiple VLANs to traverse a single switch trunk link. When a switch receives a broadcast frame on a VLAN, it forwards the frame only to ports that are members of that same VLAN, effectively isolating broadcast traffic. In real-world scenarios, VLANs are essential for separating guest Wi-Fi traffic from corporate data traffic on the same physical switch without adding routers or additional switches.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
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
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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.
Visual reference
What to study next
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FAQ
Questions learners often ask
What does this N10-009 question test?
Networking Concepts — This question tests Networking Concepts — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: VLANs — VLANs (Virtual Local Area Networks) allow a network engineer to logically segment a single physical LAN switch into multiple isolated broadcast domains without purchasing additional hardware. By assigning switch ports to different VLAN IDs, broadcast traffic is confined to ports within the same VLAN, effectively creating separate Layer 2 networks on the same switch infrastructure.
What should I do if I get this N10-009 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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 →
Same concept, more angles
2 more ways this is tested on N10-009
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which of the following is a characteristic of a Layer 2 broadcast domain?
easy- A.Devices can communicate using MAC addresses alone.
- B.All devices must be on the same IP subnet.
- ✓ C.Broadcast frames are forwarded to all ports within the domain.
- D.Routers are required to communicate between devices in the same domain.
Why C: A Layer 2 broadcast domain consists of all devices that receive a broadcast frame sent by any device within that domain. Switches forward broadcast frames (destination MAC FF:FF:FF:FF:FF:FF) out all ports except the ingress port, ensuring every device in the same VLAN or collision-free segment sees the broadcast. This is why option C is correct.
Variation 2. A network engineer is designing a network and needs to ensure that broadcast traffic is contained within a single broadcast domain. Which of the following devices should be used to create these separate broadcast domains?
medium- A.Hub
- B.Bridge
- C.Switch
- ✓ D.Router
Why D: A router operates at Layer 3 of the OSI model and does not forward broadcast frames by default, making it the correct device to segment a network into separate broadcast domains. Each interface on a router creates a distinct broadcast domain, ensuring that broadcast traffic is contained within that interface's subnet.
Keep practising
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Last reviewed: Jun 30, 2026
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