- A
A hub operates at Layer 2, while a switch operates at Layer 1.
Why wrong: This is incorrect; hubs are Layer 1 devices and switches are Layer 2 devices.
- B
A hub sends frames out all ports except the incoming port; a switch sends frames only to the port with the matching MAC address.
This accurately describes the behavior: hubs flood all ports, switches forward based on MAC address table.
- C
A hub uses MAC addresses to make forwarding decisions, while a switch uses IP addresses.
Why wrong: Hubs do not use MAC addresses for forwarding; switches use MAC addresses, not IP addresses.
- D
A hub creates a separate collision domain for each port, while a switch creates a single collision domain.
Why wrong: The opposite is true: hubs create one collision domain for all ports; switches create separate collision domains per port.
Hub vs Switch: How They Differ at OSI Layers 1 and 2
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 technician is explaining the difference between a hub and a switch to a junior technician. Which statement correctly describes a key difference between these devices?
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
A hub sends frames out all ports except the incoming port; a switch sends frames only to the port with the matching MAC address.
B is correct because a hub operates at Layer 1 (physical layer) and blindly repeats electrical signals out all ports except the incoming port, creating a single collision domain. In contrast, a switch operates at Layer 2 (data link layer) and uses the MAC address table to forward frames only to the specific port associated with the destination MAC address, reducing unnecessary traffic and creating separate collision domains per port.
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.
- ✗
A hub operates at Layer 2, while a switch operates at Layer 1.
Why it's wrong here
This is incorrect; hubs are Layer 1 devices and switches are Layer 2 devices.
When this WOULD be correct
This option would be correct if the question asked: 'Which statement incorrectly describes the difference between a hub and a switch?' or if the question was about a device that operates at Layer 2 (like a switch) versus a device that operates at Layer 1 (like a hub), but with the layers swapped.
- ✓
A hub sends frames out all ports except the incoming port; a switch sends frames only to the port with the matching MAC address.
Why this is correct
This accurately describes the behavior: hubs flood all ports, switches forward based on MAC address table.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
A hub uses MAC addresses to make forwarding decisions, while a switch uses IP addresses.
Why it's wrong here
Hubs do not use MAC addresses for forwarding; switches use MAC addresses, not IP addresses.
When this WOULD be correct
This option would be correct in a question comparing a router and a switch, where the router uses IP addresses (Layer 3) and the switch uses MAC addresses (Layer 2).
- ✗
A hub creates a separate collision domain for each port, while a switch creates a single collision domain.
Why it's wrong here
The opposite is true: hubs create one collision domain for all ports; switches create separate collision domains per port.
When this WOULD be correct
If the question asked 'Which statement correctly describes a key difference between a hub and a switch regarding collision domains?' and the options were reversed (e.g., 'A hub creates a single collision domain, a switch creates separate collision domains'), then this option would be correct.
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.
✓A hub sends frames out all ports except the incoming port; a switch sends frames only to the port with the matching MAC address.Correct answer▾
Why this is correct
This accurately describes the behavior: hubs flood all ports, switches forward based on MAC address table.
✗A hub operates at Layer 2, while a switch operates at Layer 1.Wrong answer — click to see why▾
Why this is wrong here
Hubs operate at Layer 1 (physical layer) and do not process MAC addresses, while switches operate at Layer 2 (data link layer) and use MAC addresses for forwarding. This option reverses the OSI layers for hubs and switches.
★ When this WOULD be the correct answer
This option would be correct if the question asked: 'Which statement incorrectly describes the difference between a hub and a switch?' or if the question was about a device that operates at Layer 2 (like a switch) versus a device that operates at Layer 1 (like a hub), but with the layers swapped.
Why candidates choose this
Candidates may confuse the OSI layers, thinking hubs are more intelligent than they are, or they may misremember that switches operate at Layer 2 and hubs at Layer 1, leading to a reversal of the correct layer assignments.
✗A hub uses MAC addresses to make forwarding decisions, while a switch uses IP addresses.Wrong answer — click to see why▾
Why this is wrong here
Hubs operate at Layer 1 and do not use MAC addresses; switches use MAC addresses at Layer 2. This option reverses the roles: hubs do not use MAC addresses, and switches do not use IP addresses for forwarding.
★ When this WOULD be the correct answer
This option would be correct in a question comparing a router and a switch, where the router uses IP addresses (Layer 3) and the switch uses MAC addresses (Layer 2).
Why candidates choose this
Candidates may confuse the layers of operation, thinking hubs use MAC addresses because they deal with frames, or they may mix up the functions of hubs and switches with those of routers.
✗A hub creates a separate collision domain for each port, while a switch creates a single collision domain.Wrong answer — click to see why▾
Why this is wrong here
A hub creates a single collision domain for all ports, while a switch creates a separate collision domain per port. The statement reverses these facts.
★ When this WOULD be the correct answer
If the question asked 'Which statement correctly describes a key difference between a hub and a switch regarding collision domains?' and the options were reversed (e.g., 'A hub creates a single collision domain, a switch creates separate collision domains'), then this option would be correct.
Why candidates choose this
Candidates may confuse the concepts of collision and broadcast domains, or mistakenly think that hubs segment collision domains because they are older devices, while switches are more advanced.
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 confusion between Layer 1 and Layer 2 operations, where candidates mistakenly think a hub operates at Layer 2 or that a switch uses IP addresses, but the key trap is reversing the collision domain behavior—hub creates one collision domain, switch creates many.
Detailed technical explanation
How to think about this question
Under the hood, a switch builds its MAC address table by learning the source MAC addresses of incoming frames and associating them with the ingress port; it then uses this table to make forwarding decisions. A hub, being a simple repeater, has no intelligence and regenerates the signal on all other ports, which can lead to excessive collisions and reduced throughput in half-duplex environments. In real-world scenarios, replacing a hub with a switch in a congested network can dramatically improve performance by isolating collision domains and allowing full-duplex communication.
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 practitioner preparing for the N10-009 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
Quick reference
OSI Model Reference
| Layer | Name | PDU | Key Protocols / Devices |
|---|---|---|---|
| 7 | Application | Data | HTTP, HTTPS, DNS, SMTP, FTP, SSH |
| 6 | Presentation | Data | TLS / SSL, JPEG, ASCII encoding |
| 5 | Session | Data | NetBIOS, RPC, SIP |
| 4 | Transport | Segment / Datagram | TCP, UDP |
| 3 | Network | Packet | IP, ICMP, OSPF — Routers |
| 2 | Data Link | Frame | Ethernet, Wi-Fi, PPP — Switches, Bridges |
| 1 | Physical | Bits | Cables, NICs, Hubs, Repeaters |
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: A hub sends frames out all ports except the incoming port; a switch sends frames only to the port with the matching MAC address. — B is correct because a hub operates at Layer 1 (physical layer) and blindly repeats electrical signals out all ports except the incoming port, creating a single collision domain. In contrast, a switch operates at Layer 2 (data link layer) and uses the MAC address table to forward frames only to the specific port associated with the destination MAC address, reducing unnecessary traffic and creating separate collision domains per port.
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.
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Last reviewed: Jun 11, 2026
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