- A
8 collision domains, 1 broadcast domain
Correct. Each switch port creates its own collision domain (8 total). The hub does not add separate collision domains; it connects all its ports into the collision domain of the switch port it is attached to. All devices are on the same VLAN, so there is one broadcast domain.
- B
11 collision domains, 1 broadcast domain
Why wrong: Incorrect. This answer incorrectly counts each workstation on the hub as a separate collision domain. Hubs do not segment collision domains; they operate at Layer 1 and forward all signals, so all hub-attached devices belong to the same collision domain as the switch port.
- C
12 collision domains, 5 broadcast domains
Why wrong: Incorrect. There are not 12 collision domains; the total is 8 (one per switch port). Also, a broadcast domain is not determined by the number of devices. All devices share the same broadcast domain because they are on the same VLAN and no router is involved.
- D
8 collision domains, 5 broadcast domains
Why wrong: Incorrect. While 8 collision domains is correct, 5 broadcast domains is wrong. Broadcast domains are separated by Layer 3 devices (routers), or by VLANs if trunked. Since all devices are on the same VLAN and subnet without a router, there is only one broadcast domain.
N10-009 Networking Concepts Practice Question
This N10-009 practice question tests your understanding of networking concepts. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 analyzing a small office network topology. An 8-port switch has 7 workstations directly connected. The remaining switch port is connected to a 4-port hub, which has 4 workstations attached. All devices are configured on the same VLAN and IP subnet. How many collision domains and broadcast domains are present in this network?
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
8 collision domains, 1 broadcast domain
Switches create a separate collision domain per port, so the 8-port switch provides 8 collision domains. The hub connected to one switch port extends that single collision domain to all its attached devices, but does not create new ones. All devices are on the same VLAN and IP subnet, so there is only one broadcast domain. Therefore, the network has 8 collision domains and 1 broadcast domain.
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.
- ✓
8 collision domains, 1 broadcast domain
Why this is correct
Correct. Each switch port creates its own collision domain (8 total). The hub does not add separate collision domains; it connects all its ports into the collision domain of the switch port it is attached to. All devices are on the same VLAN, so there is one broadcast domain.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
11 collision domains, 1 broadcast domain
Why it's wrong here
Incorrect. This answer incorrectly counts each workstation on the hub as a separate collision domain. Hubs do not segment collision domains; they operate at Layer 1 and forward all signals, so all hub-attached devices belong to the same collision domain as the switch port.
When this WOULD be correct
If the question stated that each hub port was connected to a separate switch port (e.g., a 4-port hub connected to 4 different switch ports), then each hub port would be its own collision domain, giving 7 (switch workstations) + 4 (hub workstations) = 11 collision domains, all in one broadcast domain.
- ✗
12 collision domains, 5 broadcast domains
Why it's wrong here
Incorrect. There are not 12 collision domains; the total is 8 (one per switch port). Also, a broadcast domain is not determined by the number of devices. All devices share the same broadcast domain because they are on the same VLAN and no router is involved.
When this WOULD be correct
This option would be correct if the network had 5 separate VLANs (each with its own broadcast domain) and the switch ports were configured in access mode for different VLANs, with the hub connecting to a switch port in a trunk mode carrying multiple VLANs, and each hub port assigned to a different VLAN. Then collision domains would be 8 (switch ports) + 4 (hub ports) = 12, and broadcast domains would be 5 (one per VLAN).
- ✗
8 collision domains, 5 broadcast domains
Why it's wrong here
Incorrect. While 8 collision domains is correct, 5 broadcast domains is wrong. Broadcast domains are separated by Layer 3 devices (routers), or by VLANs if trunked. Since all devices are on the same VLAN and subnet without a router, there is only one broadcast domain.
When this WOULD be correct
This option would be correct if the question stated that the hub's 4 workstations are each directly connected to the switch (i.e., no hub), and the network had 5 VLANs (or 5 separate IP subnets). Then there would be 8 collision domains (one per switch port) and 5 broadcast domains (one per VLAN).
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.
✓8 collision domains, 1 broadcast domainCorrect answer▾
Why this is correct
Correct. Each switch port creates its own collision domain (8 total). The hub does not add separate collision domains; it connects all its ports into the collision domain of the switch port it is attached to. All devices are on the same VLAN, so there is one broadcast domain.
✗11 collision domains, 1 broadcast domainWrong answer — click to see why▾
Why this is wrong here
The hub creates a single collision domain for its 4 ports, not 4 separate ones. The switch has 8 collision domains (one per port), but the hub's segment adds only 1, totaling 9, not 11. The correct count is 8 collision domains (7 switch ports + 1 hub segment) and 1 broadcast domain.
★ When this WOULD be the correct answer
If the question stated that each hub port was connected to a separate switch port (e.g., a 4-port hub connected to 4 different switch ports), then each hub port would be its own collision domain, giving 7 (switch workstations) + 4 (hub workstations) = 11 collision domains, all in one broadcast domain.
Why candidates choose this
Candidates mistakenly count each hub port as a separate collision domain, forgetting that a hub operates as a single collision domain for all its ports. They also may incorrectly add the hub's 4 ports to the switch's 7 ports without considering the hub's shared nature.
✗12 collision domains, 5 broadcast domainsWrong answer — click to see why▾
Why this is wrong here
A hub creates a single collision domain for all its ports, and a switch creates a separate collision domain per port. Here, the switch has 8 ports (7 workstations + 1 to hub), giving 8 collision domains. The hub adds 1 collision domain for its 4 workstations, but since it's connected to a switch port, that hub's collision domain is already counted within the switch port's collision domain. So total collision domains = 8 (switch ports) = 8. Option C incorrectly counts 12 collision domains and 5 broadcast domains, but all devices are on the same VLAN and IP subnet, so there is only 1 broadcast domain.
★ When this WOULD be the correct answer
This option would be correct if the network had 5 separate VLANs (each with its own broadcast domain) and the switch ports were configured in access mode for different VLANs, with the hub connecting to a switch port in a trunk mode carrying multiple VLANs, and each hub port assigned to a different VLAN. Then collision domains would be 8 (switch ports) + 4 (hub ports) = 12, and broadcast domains would be 5 (one per VLAN).
Why candidates choose this
Candidates often mistakenly count each hub port as a separate collision domain (adding 4 instead of 1) and think that a hub creates multiple broadcast domains, confusing collision and broadcast domain concepts.
✗8 collision domains, 5 broadcast domainsWrong answer — click to see why▾
Why this is wrong here
A switch creates a separate collision domain per port, so the 8-port switch provides 8 collision domains. The hub creates a single collision domain for its 4 workstations, but that hub port on the switch is already counted as one collision domain. Thus total collision domains = 8 (switch ports) = 8, not 8 + 4 = 12. Broadcast domain is one because all devices are on the same VLAN and IP subnet.
★ When this WOULD be the correct answer
This option would be correct if the question stated that the hub's 4 workstations are each directly connected to the switch (i.e., no hub), and the network had 5 VLANs (or 5 separate IP subnets). Then there would be 8 collision domains (one per switch port) and 5 broadcast domains (one per VLAN).
Why candidates choose this
Candidates often mistakenly count each hub-attached workstation as a separate collision domain, adding 4 to the switch's 8, and may also think that a hub creates multiple broadcast domains or confuse collision and 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
The N10-009 exam often tests the distinction between hubs (Layer 1 repeaters that extend collision domains) and switches (Layer 2 devices that segment collision domains), and the trap here is assuming that each hub port creates its own collision domain, leading to overcounting collision domains, or confusing collision domains with broadcast domains by thinking hubs or switches create multiple broadcast domains.
Detailed technical explanation
How to think about this question
In Ethernet, a collision domain is a network segment where collisions can occur; switches isolate each port into its own collision domain using store-and-forward buffering, while hubs electrically repeat all signals, forcing all attached devices into one collision domain. Broadcast domains are Layer 2 boundaries defined by VLANs or routers; even with multiple switches, all ports in the same VLAN belong to one broadcast domain. In real-world scenarios, mixing hubs with switches can degrade performance due to increased collisions on the hub segment, which is why modern networks use switches exclusively.
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: 8 collision domains, 1 broadcast domain — Switches create a separate collision domain per port, so the 8-port switch provides 8 collision domains. The hub connected to one switch port extends that single collision domain to all its attached devices, but does not create new ones. All devices are on the same VLAN and IP subnet, so there is only one broadcast domain. Therefore, the network has 8 collision domains and 1 broadcast domain.
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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