Quick Answer
The answer is a switch, because it is the device used to connect switches and extend a single LAN across multiple floors. A switch operates at Layer 2 of the OSI model, forwarding frames based on MAC addresses, which allows it to interconnect other switches and keep all connected devices within the same broadcast domain. This means no routing or IP subnet changes are needed—just a simple Ethernet or fiber uplink between the switches creates one unified local area network. On the CompTIA ITF+ FC0-U61 exam, this question tests your understanding of basic networking hardware and the difference between Layer 2 switching and Layer 3 routing; a common trap is choosing a router, which would split the network into separate subnets. Remember the memory tip: “Switches stay local, routers roam global”—if the goal is to extend a single LAN without breaking it into separate networks, a switch is always the right tool.
This FC0-U61 practice question tests your understanding of infrastructure. 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.
A company has two departments on separate floors and wants to connect them into a single local area network (LAN). Which device should be used to interconnect the switches on each floor?
Router
Why wrong: Routers are used to connect different networks, not to extend a single LAN.
Modem
Why wrong: Modems connect to an internet service provider, not for local network interconnection.
Switch
Switches connect devices within the same network, allowing multiple switches to extend a LAN.
Hub
Why wrong: Hubs are legacy devices that broadcast all traffic and are not suitable for modern networks.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Switch
A switch is the correct device because it operates at Layer 2 (Data Link layer) and can forward frames based on MAC addresses, allowing multiple switches to be interconnected to extend a single broadcast domain and form a larger LAN. Connecting switches on different floors via Ethernet cables or fiber uplinks creates a unified local area network without requiring routing or network-layer addressing.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Router
Why it's wrong here
Routers are used to connect different networks, not to extend a single LAN.
Modem
Why it's wrong here
Modems connect to an internet service provider, not for local network interconnection.
Switch
Why this is correct
Switches connect devices within the same network, allowing multiple switches to extend a LAN.
Related concept
Read the scenario before looking for a memorised answer.
Hub
Why it's wrong here
Hubs are legacy devices that broadcast all traffic and are not suitable for modern networks.
Common exam traps
The trap here is that candidates often confuse a router as necessary for connecting any two network segments, but when the goal is to extend the same LAN (same subnet and broadcast domain), a Layer 2 switch is the appropriate device, not a router.
Detailed technical explanation
When interconnecting switches, the uplink ports typically use auto-MDIX to handle crossover vs. straight-through cables, and spanning tree protocol (STP, IEEE 802.1D) runs automatically to prevent loops if multiple links exist between the switches. In a real-world scenario, using fiber optic cabling between floors can extend the LAN beyond the 100-meter copper limit while maintaining full-duplex communication.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A network engineer segments a warehouse floor into three subnets: 20 scanners, 5 printers, and 2 management hosts. Picking the wrong mask wastes addresses or leaves too few usable hosts. Exam questions test whether you can apply CIDR notation, calculate block size, and identify the correct usable-host range for a given prefix.
What to study next
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FAQ
Infrastructure — This question tests Infrastructure — Read the scenario before looking for a memorised answer..
The correct answer is: Switch — A switch is the correct device because it operates at Layer 2 (Data Link layer) and can forward frames based on MAC addresses, allowing multiple switches to be interconnected to extend a single broadcast domain and form a larger LAN. Connecting switches on different floors via Ethernet cables or fiber uplinks creates a unified local area network without requiring routing or network-layer addressing.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 25, 2026
This FC0-U61 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 FC0-U61 exam.
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