N10-009 Networking Concepts Practice Question
Which of the following best describes a broadcast domain?
⚠ Common exam trap
Many candidates confuse a broadcast domain with a collision domain or assume all devices on the same switch are in the same broadcast domain, ignoring VLAN segmentation.
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
✓
All devices that can receive a broadcast frame from any other device in the network segment
A broadcast domain is defined as the set of all devices that can receive a broadcast frame (destination MAC FF:FF:FF:FF:FF:FF) sent by any other device within the same network segment. This boundary is typically enforced by Layer 3 devices like routers, which do not forward broadcast frames, whereas Layer 2 switches forward broadcasts out all ports except the receiving port within the same VLAN.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
All devices connected to the same switch
Why it's wrong here
While a basic unmanaged switch or a switch configured without Virtual Local Area Networks (VLANs) would indeed place all connected devices into a single broadcast domain, this statement is generally inaccurate for modern, managed network environments. VLANs logically segment a single physical switch into multiple distinct broadcast domains, preventing broadcast frames from traversing between different VLANs. Therefore, devices connected to the same physical switch but assigned to different VLANs cannot receive each other's broadcast frames.
When this WOULD be correct
In a question asking 'Which of the following best describes a collision domain?' or 'Which device extends a collision domain?', option A would be correct because all devices connected to the same switch (without VLANs) share the same collision domain only if hubs are used; but more precisely, a switch separates collision domains per port, so this option is rarely correct. Alternatively, if the question specifies 'a single VLAN on a switch', then all devices in that VLAN are in the same broadcast domain, but the option as stated is too broad.
- ✗
All devices that share the same IP subnet
Why it's wrong here
An IP subnet defines a logical grouping of IP addresses at Layer 3, facilitating efficient routing and address management. While devices within the same IP subnet are typically configured to reside within the same broadcast domain, the two concepts are not synonymous. A single IP subnet can span multiple Layer 2 broadcast domains (e.g., across routed VLANs), or conversely, multiple IP subnets can exist within a single, large Layer 2 broadcast domain, demonstrating their distinct nature.
When this WOULD be correct
For a question asking 'Which of the following best describes a subnet?' or 'What is a characteristic of devices in the same IP subnet?', option B would be correct because devices in the same subnet can communicate directly without a router.
- ✓
All devices that can receive a broadcast frame from any other device in the network segment
Why this is correct
A broadcast domain is fundamentally a Layer 2 concept, encompassing all devices that receive a broadcast frame originating from any other device within that same logical segment. Routers typically act as boundaries, preventing broadcasts from traversing into other domains, while switches, within a single VLAN, propagate these frames to all connected ports. This definition precisely captures the scope of network communication where a single broadcast will reach every participant.
- ✗
All devices that have the same MAC address prefix
Why it's wrong here
A MAC address prefix, also known as the Organizationally Unique Identifier (OUI), serves to identify the manufacturer of a network interface card or hardware device. This identifier is purely for hardware identification and has no functional bearing on network segmentation, broadcast domain boundaries, or how broadcast frames are propagated. Devices from various manufacturers can freely coexist within the same broadcast domain, and conversely, devices from the same manufacturer can be in entirely separate domains.
When this WOULD be correct
In a question asking 'Which of the following best describes a group of devices with the same OUI (Organizationally Unique Identifier)?' or 'What is a characteristic of devices from the same vendor based on MAC addressing?', 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.
✓All devices that can receive a broadcast frame from any other device in the network segmentCorrect answer▾
Why this is correct
A broadcast domain is fundamentally a Layer 2 concept, encompassing all devices that receive a broadcast frame originating from any other device within that same logical segment. Routers typically act as boundaries, preventing broadcasts from traversing into other domains, while switches, within a single VLAN, propagate these frames to all connected ports. This definition precisely captures the scope of network communication where a single broadcast will reach every participant.
✗All devices connected to the same switchWrong answer — click to see why▾
Why this is wrong here
A broadcast domain is defined by the ability to receive broadcast frames, not by physical connectivity to the same switch. A single switch can be divided into multiple VLANs, each forming a separate broadcast domain, so all devices on the same switch may belong to different broadcast domains.
★ When this WOULD be the correct answer
In a question asking 'Which of the following best describes a collision domain?' or 'Which device extends a collision domain?', option A would be correct because all devices connected to the same switch (without VLANs) share the same collision domain only if hubs are used; but more precisely, a switch separates collision domains per port, so this option is rarely correct. Alternatively, if the question specifies 'a single VLAN on a switch', then all devices in that VLAN are in the same broadcast domain, but the option as stated is too broad.
Why candidates choose this
Candidates often confuse broadcast domains with physical connectivity, assuming that being on the same switch implies receiving all broadcasts, ignoring VLAN segmentation.
✗All devices that share the same IP subnetWrong answer — click to see why▾
Why this is wrong here
A broadcast domain is defined by the ability to receive broadcast frames, not by IP subnet membership. Devices in different subnets can be in the same broadcast domain if connected via a bridge or switch without a router.
★ When this WOULD be the correct answer
For a question asking 'Which of the following best describes a subnet?' or 'What is a characteristic of devices in the same IP subnet?', option B would be correct because devices in the same subnet can communicate directly without a router.
Why candidates choose this
Candidates often confuse broadcast domains with subnets because routers typically separate both, leading them to assume that sharing an IP subnet implies being in the same broadcast domain.
✗All devices that have the same MAC address prefixWrong answer — click to see why▾
Why this is wrong here
A broadcast domain is defined by the ability to receive broadcast frames, not by MAC address prefix. MAC address prefixes identify the manufacturer, not broadcast boundaries.
★ When this WOULD be the correct answer
In a question asking 'Which of the following best describes a group of devices with the same OUI (Organizationally Unique Identifier)?' or 'What is a characteristic of devices from the same vendor based on MAC addressing?', this option would be correct.
Why candidates choose this
Candidates may confuse MAC address prefixes with network segmentation concepts, thinking that similar MAC prefixes imply a common broadcast domain, especially when studying layer 2 addressing.
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?”
Visual reference
Quick reference
Access Control Model Comparison
| Model | Acronym | Who Controls Access? | Best For |
|---|---|---|---|
| Discretionary Access Control | DAC | Resource owner | Small teams, file shares |
| Mandatory Access Control | MAC | System / security labels | Classified govt / military |
| Role-Based Access Control | RBAC | Administrator (via roles) | Enterprise environments |
| Attribute-Based Access Control | ABAC | Policy engine (user + resource attributes) | Fine-grained, dynamic policies |
| Rule-Based Access Control | RuBAC | System rules / ACLs | Firewall rules, network ACLs |
Go deeper
Related to this question
Learn chapter
Network Virtualization and VXLAN
Key term
Frame
A frame is a unit of data at the Data Link layer of networking, containing header, payload, and trailer information for local network delivery.
Key term
VLAN
A VLAN (Virtual Local Area Network) is a logical grouping of network devices that behave as if they are on the same physical network segment, regardless of their actual physical location.
About these practice questions
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.