N10-009 Network Operations Practice Question
A network technician notices a high volume of broadcast traffic on a flat network. Which device will best reduce the size of the broadcast domain?
⚠ Common exam trap
Many exam-takers confuse broadcast domains with collision domains, incorrectly assuming that a switch reduces broadcast domains because it reduces collision domains, but a switch only segments collision domains while leaving broadcast domains intact.
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 is the correct choice because it operates at Layer 3 and uses IP subnetting to segment a network into separate broadcast domains. By default, routers do not forward broadcast traffic (e.g., ARP requests sent to 255.255.255.255 or subnet-directed broadcasts) between interfaces, thus reducing the scope of broadcast propagation.
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
Hubs are Layer 1 (Physical Layer) devices that lack any intelligence regarding network traffic. They simply receive an electrical signal on one port and regenerate it, sending it out to all other connected ports without any filtering or forwarding decisions. This fundamental operation means that all devices connected to a hub share a single collision domain and, critically, a single large broadcast domain, exacerbating broadcast traffic issues rather than mitigating them.
When this WOULD be correct
A hub would be the correct answer if the question asked which device extends a collision domain or connects multiple devices in a single collision domain without any segmentation.
- ✗
Switch
Why it's wrong here
A network switch operates at Layer 2 (the Data Link Layer) and creates a separate collision domain for each connected port, significantly reducing collisions. However, by default, a switch forwards all broadcast frames received on one port to every other port within the same VLAN. Without the implementation of Virtual Local Area Networks (VLANs) to create multiple logical broadcast domains, a single switch effectively constitutes one large broadcast domain, thus failing to reduce overall broadcast traffic.
When this WOULD be correct
A switch would be the correct answer if the question asked which device reduces collision domains (by providing dedicated bandwidth per port) or segments a network at Layer 2 without affecting broadcast domains.
- ✓
Router
Why this is correct
Routers operate at Layer 3 (the Network Layer) of the OSI model, making forwarding decisions based on IP addresses. A key function of a router is to segment a network into multiple broadcast domains, as they do not forward broadcast traffic from one interface to another by default. By connecting different subnets, a router effectively contains broadcast storms within their respective segments, significantly reducing overall broadcast traffic on the larger network. This isolation improves network efficiency and security.
- ✗
Bridge
Why it's wrong here
Bridges operate at Layer 2 (the Data Link Layer) and learn MAC addresses to segment a single collision domain into multiple, smaller collision domains. While they improve performance by forwarding frames only to the segment where the destination MAC address resides, bridges inherently forward all broadcast frames to every connected segment. Consequently, a bridge does not reduce the size of the broadcast domain, allowing broadcast storms to propagate across the entire bridged network.
When this WOULD be correct
A bridge would be correct in a question asking which device reduces collision domains without requiring IP routing, such as 'Which device can segment a network into separate collision domains while remaining transparent to broadcast traffic?'
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
Routers operate at Layer 3 (the Network Layer) of the OSI model, making forwarding decisions based on IP addresses. A key function of a router is to segment a network into multiple broadcast domains, as they do not forward broadcast traffic from one interface to another by default. By connecting different subnets, a router effectively contains broadcast storms within their respective segments, significantly reducing overall broadcast traffic on the larger network. This isolation improves network efficiency and security.
✗HubWrong answer — click to see why▾
Why this is wrong here
Hubs operate at Layer 1 and simply repeat all signals out all ports, so they do not segment broadcast domains; all devices connected to a hub remain in the same broadcast domain.
★ When this WOULD be the correct answer
A hub would be the correct answer if the question asked which device 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, thinking that a hub, like a switch, can reduce broadcast traffic by separating devices, but hubs actually increase collisions and do not filter broadcasts.
✗SwitchWrong answer — click to see why▾
Why this is wrong here
A switch forwards broadcast traffic to all ports within the same VLAN, so it does not reduce the size of the broadcast domain; it actually extends it.
★ When this WOULD be the correct answer
A switch would be the correct answer if the question asked which device reduces collision domains (by providing dedicated bandwidth per port) or segments a network at Layer 2 without affecting broadcast domains.
Why candidates choose this
Candidates often confuse broadcast domains with collision domains, mistakenly thinking that switches reduce broadcast traffic because they reduce collisions.
✗BridgeWrong answer — click to see why▾
Why this is wrong here
A bridge reduces collision domains but does not reduce broadcast domains; it forwards broadcasts to all segments, so it would not reduce broadcast traffic in a flat network.
★ When this WOULD be the correct answer
A bridge would be correct in a question asking which device reduces collision domains without requiring IP routing, such as 'Which device can segment a network into separate collision domains while remaining transparent to broadcast traffic?'
Why candidates choose this
Candidates may confuse bridges with routers, thinking that because bridges segment networks, they also reduce broadcast domains, or they may recall that bridges filter traffic based on MAC addresses and assume that includes broadcasts.
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
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Related to this question
Learn chapter
Network Documentation and Diagrams
Key term
Variable Length Subnet Mask
A Variable Length Subnet Mask (VLSM) allows network engineers to divide an IP address space into subnets of different sizes, using different subnet masks for each subnet to match the exact number of hosts needed.
Key term
ARP
Address Resolution Protocol (ARP) is a network protocol used to map a device's IP address to its physical MAC address so data can be delivered correctly on a local 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.