N10-009 Networking Concepts Practice Question
A network engineer is designing a network and needs to ensure that broadcast traffic is contained within a single broadcast domain. Which of the following devices should be used to create these separate broadcast domains?
⚠ Common exam trap
The N10-009 exam often tests the misconception that a switch creates separate broadcast domains, but a switch only separates collision domains; without VLANs, all ports on a switch belong to the same 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
✓
Router
A router operates at Layer 3 of the OSI model and does not forward broadcast frames by default, making it the correct device to segment a network into separate broadcast domains. Each interface on a router creates a distinct broadcast domain, ensuring that broadcast traffic is contained within that interface's subnet.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Hub
Why it's wrong here
A hub is a rudimentary Layer 1 device that functions as a multi-port repeater, simply regenerating and transmitting any incoming electrical signal out to all other connected ports. It lacks any intelligence to interpret MAC or IP addresses, meaning all devices connected to a hub share a single collision domain and a single broadcast domain. Consequently, broadcast traffic received on one port is indiscriminately flooded to every other port, making it ineffective for broadcast segmentation.
When this WOULD be correct
A hub would be the correct answer if the question asked for a device that extends a collision domain or connects multiple devices in a single collision domain without any segmentation.
- ✗
Bridge
Why it's wrong here
Operating at Layer 2, a bridge learns MAC addresses of devices on connected segments and forwards frames selectively based on destination MACs. While a bridge can segment collision domains by intelligently forwarding unicast traffic, it does not filter or contain broadcast frames. Any broadcast frame received on one port is always flooded out to all other ports, meaning a bridge does not separate broadcast domains.
When this WOULD be correct
A bridge would be correct in a question asking for a device that connects two separate network segments while filtering traffic based on MAC addresses to reduce collisions, but does not need to separate broadcast domains.
- ✗
Switch
Why it's wrong here
A standard Ethernet switch, also a Layer 2 device, builds a MAC address table to intelligently forward unicast frames only to the destination port. However, in the absence of Virtual Local Area Networks (VLANs), a switch treats all connected ports as part of a single broadcast domain. Therefore, any broadcast frame received on one port will be flooded out to all other ports within that same broadcast domain, failing to contain broadcast traffic.
When this WOULD be correct
A switch would be correct if the question asked for a device that creates separate collision domains or segments a LAN into multiple collision domains, as each port on a switch is a separate collision domain.
- ✓
Router
Why this is correct
A router operates at Layer 3 of the OSI model, making forwarding decisions based on IP addresses. By default, a router does not forward Layer 2 broadcast frames from one interface to another, effectively creating a distinct broadcast domain on each of its connected network segments. This fundamental function is crucial for segmenting large networks, preventing broadcast traffic from overwhelming interconnected subnets and improving overall network efficiency.
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.
✓RouterCorrect answer▾
Why this is correct
A router operates at Layer 3 of the OSI model, making forwarding decisions based on IP addresses. By default, a router does not forward Layer 2 broadcast frames from one interface to another, effectively creating a distinct broadcast domain on each of its connected network segments. This fundamental function is crucial for segmenting large networks, preventing broadcast traffic from overwhelming interconnected subnets and improving overall network efficiency.
✗HubWrong answer — click to see why▾
Why this is wrong here
Hubs operate at Layer 1 and simply repeat electrical signals out all ports, so they do not segment broadcast domains; all devices connected to a hub share the same broadcast domain.
★ When this WOULD be the correct answer
A hub would be the correct answer if the question asked for a device that extends a collision domain or connects multiple devices in a single collision domain without any segmentation.
Why candidates choose this
Candidates may confuse broadcast domains with collision domains, or think that any network device can isolate traffic, not realizing that only routers (or VLANs with a router) can separate broadcast domains.
✗BridgeWrong answer — click to see why▾
Why this is wrong here
Bridges operate at Layer 2 and forward frames based on MAC addresses, but they do not filter broadcast traffic; broadcasts are flooded to all ports within the same broadcast domain.
★ When this WOULD be the correct answer
A bridge would be correct in a question asking for a device that connects two separate network segments while filtering traffic based on MAC addresses to reduce collisions, but does not need to separate broadcast domains.
Why candidates choose this
Candidates may confuse bridges with routers, thinking that bridges can segment broadcast domains because they can filter traffic, but bridges actually forward broadcasts, not block them.
✗SwitchWrong answer — click to see why▾
Why this is wrong here
A switch operates at Layer 2 and forwards frames based on MAC addresses, but it does not filter broadcast traffic; all ports in the same VLAN belong to the same broadcast domain. Therefore, a switch alone cannot separate broadcast domains.
★ When this WOULD be the correct answer
A switch would be correct if the question asked for a device that creates separate collision domains or segments a LAN into multiple collision domains, as each port on a switch is a separate collision domain.
Why candidates choose this
Candidates often confuse broadcast domains with collision domains, or they assume that switches can filter broadcasts because they segment traffic based on MAC addresses, not realizing that broadcasts are flooded to all ports in the same VLAN.
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
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 |
Go deeper
Related to this question
Learn chapter
Network Virtualization and VXLAN
Key term
Segment
A segment is a division of a larger network, such as a collision domain, broadcast domain, or a portion of a TCP data stream, used to organize traffic and improve performance.
Key term
Open Systems Interconnection
The Open Systems Interconnection (OSI) model is a conceptual framework used to understand how data travels from one computer to another across a network.
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.