- A
Devices can communicate using MAC addresses alone.
Why wrong: Devices within the same broadcast domain can communicate using MAC addresses, but this is not a defining characteristic of a broadcast domain; it is true for any Layer 2 network segment.
- B
All devices must be on the same IP subnet.
Why wrong: While devices in the same broadcast domain are often on the same subnet, it is not a Layer 2 requirement. VLANs logically separate broadcast domains, and IP subnetting is typically aligned.
- C
Broadcast frames are forwarded to all ports within the domain.
The key characteristic of a broadcast domain is that a broadcast frame sent by any device is received by all other devices in that domain. Switches forward broadcasts to all ports in the same VLAN.
- D
Routers are required to communicate between devices in the same domain.
Why wrong: Routers are not needed for communication within the same broadcast domain; switches handle Layer 2 forwarding. Routers are only required to communicate between different broadcast domains (subnets).
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.
Which of the following is a characteristic of a Layer 2 broadcast domain?
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
Broadcast frames are forwarded to all ports within the domain.
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.
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.
- ✗
Devices can communicate using MAC addresses alone.
Why it's wrong here
Devices within the same broadcast domain can communicate using MAC addresses, but this is not a defining characteristic of a broadcast domain; it is true for any Layer 2 network segment.
- ✗
All devices must be on the same IP subnet.
Why it's wrong here
While devices in the same broadcast domain are often on the same subnet, it is not a Layer 2 requirement. VLANs logically separate broadcast domains, and IP subnetting is typically aligned.
- ✓
Broadcast frames are forwarded to all ports within the domain.
Why this is correct
The key characteristic of a broadcast domain is that a broadcast frame sent by any device is received by all other devices in that domain. Switches forward broadcasts to all ports in the same VLAN.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Routers are required to communicate between devices in the same domain.
Why it's wrong here
Routers are not needed for communication within the same broadcast domain; switches handle Layer 2 forwarding. Routers are only required to communicate between different broadcast domains (subnets).
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse a broadcast domain with a collision domain, or incorrectly assume that being on the same IP subnet is a requirement for receiving broadcasts, when in fact Layer 2 broadcasts are forwarded regardless of IP addressing.
Detailed technical explanation
How to think about this question
Under the hood, a broadcast domain is typically bounded by a router or Layer 3 interface, as routers do not forward broadcast frames by default. In a VLAN environment, each VLAN is a separate broadcast domain, and switches use the VLAN ID to isolate broadcast traffic. A real-world scenario: if a misconfigured device sends a broadcast storm, it can saturate the entire broadcast domain, causing network degradation for all devices in that VLAN.
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.
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: Broadcast frames are forwarded to all ports within the domain. — 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.
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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