- A
Spanning Tree Protocol (STP)
Why wrong: STP prevents loops in redundant topologies but does not create broadcast domains.
- B
Virtual LAN (VLAN)
VLANs segment a physical switch into multiple broadcast domains at Layer 2, requiring a router for inter-VLAN communication.
- C
Subnetting
Why wrong: Subnetting is a Layer 3 concept that divides IP address space; it does not create broadcast domains on a switch without VLANs.
- D
Quality of Service (QoS)
Why wrong: QoS prioritizes traffic but does not affect broadcast domain segmentation.
Question 419 of 520
N10-009 Networking Concepts Practice Question
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 administrator wants to logically segment a single physical switch into multiple separate broadcast domains without purchasing additional hardware. Which concept should be used?
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
✓
Virtual LAN (VLAN)
A VLAN logically segments a physical switch into multiple isolated broadcast domains by assigning switch ports to specific VLAN IDs (802.1Q). This prevents broadcast traffic from crossing VLAN boundaries without requiring additional hardware, as each VLAN functions as its own Layer 2 network.
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.
- ✗
Spanning Tree Protocol (STP)
Why it's wrong here
STP prevents loops in redundant topologies but does not create broadcast domains.
When this WOULD be correct
A question asking: 'Which protocol prevents bridging loops in a redundant switched network?' would make STP the correct answer, as it ensures loop-free topology by blocking redundant links.
- ✓
Virtual LAN (VLAN)
Why this is correct
VLANs segment a physical switch into multiple broadcast domains at Layer 2, requiring a router for inter-VLAN communication.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Subnetting
Why it's wrong here
Subnetting is a Layer 3 concept that divides IP address space; it does not create broadcast domains on a switch without VLANs.
When this WOULD be correct
A network administrator needs to divide a single IP network into smaller, more manageable subnetworks to improve routing efficiency and reduce broadcast traffic at Layer 3, without changing the physical network topology.
- ✗
Quality of Service (QoS)
Why it's wrong here
QoS prioritizes traffic but does not affect broadcast domain segmentation.
When this WOULD be correct
A network administrator needs to prioritize voice traffic over data traffic on a congested link to ensure call quality. QoS policies would be the correct solution.
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.
✓Virtual LAN (VLAN)Correct answer▾
Why this is correct
VLANs segment a physical switch into multiple broadcast domains at Layer 2, requiring a router for inter-VLAN communication.
✗Spanning Tree Protocol (STP)Wrong answer — click to see why▾
Why this is wrong here
STP prevents loops in a network topology but does not segment a switch into multiple broadcast domains; it operates at Layer 2 to manage redundant paths, not to create separate logical networks.
★ When this WOULD be the correct answer
A question asking: 'Which protocol prevents bridging loops in a redundant switched network?' would make STP the correct answer, as it ensures loop-free topology by blocking redundant links.
Why candidates choose this
Candidates may confuse STP with VLANs because both are Layer 2 concepts, or they might think STP can segment traffic by blocking certain paths, but STP's purpose is loop prevention, not segmentation.
✗SubnettingWrong answer — click to see why▾
Why this is wrong here
Subnetting is a logical division of an IP network at Layer 3, not a method to segment a single physical switch into multiple broadcast domains at Layer 2. VLANs operate at Layer 2 to create separate broadcast domains on the same switch.
★ When this WOULD be the correct answer
A network administrator needs to divide a single IP network into smaller, more manageable subnetworks to improve routing efficiency and reduce broadcast traffic at Layer 3, without changing the physical network topology.
Why candidates choose this
Candidates may confuse subnetting with VLANs because both involve segmentation, but subnetting is IP-based and works across routers, while VLANs are switch-based and create separate broadcast domains at Layer 2.
✗Quality of Service (QoS)Wrong answer — click to see why▾
Why this is wrong here
QoS prioritizes network traffic but does not segment a switch into separate broadcast domains; it manages bandwidth allocation, not logical separation.
★ When this WOULD be the correct answer
A network administrator needs to prioritize voice traffic over data traffic on a congested link to ensure call quality. QoS policies would be the correct solution.
Why candidates choose this
Candidates may confuse traffic management with segmentation, thinking QoS can isolate traffic types similarly to VLANs.
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
The N10-009 exam often tests the misconception that subnetting alone can segment a switch, but subnetting is a Layer 3 concept and does not create separate broadcast domains on a single physical switch without VLANs.
Detailed technical explanation
How to think about this question
VLANs use 802.1Q tagging to insert a 4-byte tag into Ethernet frames, allowing multiple VLANs to traverse a single trunk link while keeping traffic separate. Without a Layer 3 device (router or Layer 3 switch), VLANs cannot communicate with each other, reinforcing their role as isolated broadcast domains. In real-world scenarios, VLANs are often paired with VTP (VLAN Trunking Protocol) or manual configuration to scale across multiple 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: Virtual LAN (VLAN) — A VLAN logically segments a physical switch into multiple isolated broadcast domains by assigning switch ports to specific VLAN IDs (802.1Q). This prevents broadcast traffic from crossing VLAN boundaries without requiring additional hardware, as each VLAN functions as its own Layer 2 network.
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
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Last reviewed: Jun 11, 2026
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