The answer is Virtual LAN (VLAN). A VLAN logically segments a single physical switch into multiple isolated broadcast domains by assigning switch ports to specific VLAN IDs per the 802.1Q standard, which prevents broadcast traffic from crossing VLAN boundaries without requiring additional hardware. On the CompTIA Network+ N10-009 exam, this concept tests your understanding of how to improve network performance and security through logical segmentation, often appearing in scenario-based questions where a technician must reduce broadcast overhead or isolate sensitive traffic without buying new switches. A common trap is confusing VLANs with subnetting—remember that VLANs operate at Layer 2 to separate broadcast domains, while subnets separate at Layer 3. For a quick memory tip: think of a VLAN as a virtual wall inside the same switch, keeping broadcast chatter contained to its own room.
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 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.
✓
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.
Common exam trap: answer the scenario, not the keyword
Cisco 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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this N10-009 question in full detail.
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
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 N10-009 practice question is part of Courseiva's free CompTIA 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 N10-009 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.