Quick Answer
The answer is cut-through switching, separate collision domains, and hardware-based MAC address forwarding. Layer 2 switches improve network performance by creating a dedicated collision domain on each port, which eliminates collisions between devices on different ports and allows full-duplex communication. They also forward frames based solely on the destination MAC address, enabling fast, hardware-driven switching that avoids the latency of software-based lookups. On the CCNA 200-301 v2 exam, this topic tests your understanding of how switches reduce congestion at Layer 2, often appearing in a “choose three” format where common traps include confusing collision domains with broadcast domains or assuming switches use IP addresses. A frequent distractor is the claim that switches reduce broadcast domains—remember, only routers or VLANs break up broadcasts. Memory tip: think “MAC, no collisions, cut through” to recall the three key performance boosters.
CCNA Network Infrastructure and Connectivity Practice Question
This 200-301 practice question tests your understanding of network infrastructure and connectivity. 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 three of the following are characteristics of Layer 2 Ethernet switches that improve network performance? (Choose three.)
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
They create separate collision domains per port.
Layer 2 Ethernet switches improve network performance by creating separate collision domains per port, eliminating collisions between devices on different ports. They forward frames based on the destination MAC address, enabling efficient hardware-based switching. Cut-through switching reduces latency by starting to forward as soon as the destination MAC address is read. The other options are incorrect: switches do not reduce broadcast domains (broadcasts are forwarded to all ports in the same VLAN unless a router or VLAN segmentation is used); switches operate at Layer 2 using MAC addresses, not IP addresses; and unknown unicast frames are flooded out all ports except the incoming port, not automatically blocked, to ensure connectivity if the destination is unknown.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distinction between collision domains and broadcast domains, where candidates mistakenly think switches reduce broadcast domains, but switches only segment collision domains while broadcast domains are controlled by VLANs or routers.
Detailed technical explanation
How to think about this question
Cut-through switching can be implemented as fast-forward (immediate forwarding after destination MAC) or fragment-free (forwarding after checking the first 64 bytes to avoid collision fragments). In real-world scenarios, cut-through is preferred in low-latency environments like data centers, but store-and-forward is used when error checking is critical, such as on uplinks with high error rates. The switch builds its MAC address table by learning source MAC addresses from incoming frames, and only floods unknown unicast frames until the destination is learned.
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 200-301 question test?
Network Infrastructure and Connectivity — This question tests Network Infrastructure and Connectivity — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: They create separate collision domains per port. — Layer 2 Ethernet switches improve network performance by creating separate collision domains per port, eliminating collisions between devices on different ports. They forward frames based on the destination MAC address, enabling efficient hardware-based switching. Cut-through switching reduces latency by starting to forward as soon as the destination MAC address is read. The other options are incorrect: switches do not reduce broadcast domains (broadcasts are forwarded to all ports in the same VLAN unless a router or VLAN segmentation is used); switches operate at Layer 2 using MAC addresses, not IP addresses; and unknown unicast frames are flooded out all ports except the incoming port, not automatically blocked, to ensure connectivity if the destination is unknown.
What should I do if I get this 200-301 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
This 200-301 practice question is part of Courseiva's free Cisco 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 200-301 exam.
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