This 200-301 practice question tests your understanding of switching and network access. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. A key principle to apply: power over Ethernet (PoE) delivers electrical power and data simultaneously over a single Ethernet cable to network devices.. 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.
What is the purpose of Power over Ethernet (PoE)?
To encrypt Ethernet frames
Why wrong: PoE has nothing to do with frame encryption.
To deliver electrical power over Ethernet cabling
Correct. PoE supplies power over Ethernet cabling.
To compress voice traffic on a LAN
Why wrong: PoE does not compress traffic.
To increase the maximum IPv4 MTU
Why wrong: PoE does not change the MTU.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
To deliver electrical power over Ethernet cabling
PoE allows network devices such as IP phones, wireless access points, and cameras to receive power through the same Ethernet cable used for data.
Key principle: Power over Ethernet (PoE) delivers electrical power and data simultaneously over a single Ethernet cable to network devices.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
To encrypt Ethernet frames
Why it's wrong here
PoE has nothing to do with frame encryption.
To deliver electrical power over Ethernet cabling
Why this is correct
Correct. PoE supplies power over Ethernet cabling.
Related concept
Power over Ethernet (PoE) delivers electrical power and data simultaneously over a single Ethernet cable to network devices.
To compress voice traffic on a LAN
Why it's wrong here
PoE does not compress traffic.
When this WOULD be correct
If the exam question asked about technologies specifically designed for optimizing voice over IP (VoIP) traffic on a local area network, and included options related to traffic management, then compressing voice traffic could be a correct answer.
To increase the maximum IPv4 MTU
Why it's wrong here
PoE does not change the MTU.
When this WOULD be correct
In a different context, a question asking about methods to optimize network performance might present option D as correct if it were framed around increasing MTU size to improve throughput for large data transfers in a specific network configuration.
Option-by-option analysis
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
Why this is correct
Correct. PoE supplies power over Ethernet cabling.
Why this is wrong here
This option is wrong because Power over Ethernet (PoE) does not involve encryption of Ethernet frames; its primary function is to deliver power alongside data over the same cabling.
★ When this WOULD be the correct answer
This option would be correct in a question asking about methods of securing data transmission over networks, where the focus is on encryption technologies such as IPsec or SSL/TLS, and the context is specifically about securing Ethernet frames.
Why candidates choose this
Candidates may choose this option due to a misunderstanding of network protocols, confusing PoE's electrical capabilities with security features, or because they recognize the importance of encryption in network communications.
Why this is wrong here
Option C is incorrect because Power over Ethernet (PoE) is not related to voice traffic compression; it is designed to deliver electrical power alongside data over Ethernet cables.
★ When this WOULD be the correct answer
If the exam question asked about technologies specifically designed for optimizing voice over IP (VoIP) traffic on a local area network, and included options related to traffic management, then compressing voice traffic could be a correct answer.
Why candidates choose this
Candidates may choose this option due to a misunderstanding of PoE's role in network infrastructure, confusing it with technologies that enhance voice communication quality, such as compression methods.
Why this is wrong here
Option D is incorrect because Power over Ethernet (PoE) does not pertain to modifying the maximum transmission unit (MTU) size for IPv4 packets; it focuses on delivering power alongside data over Ethernet cables.
★ When this WOULD be the correct answer
In a different context, a question asking about methods to optimize network performance might present option D as correct if it were framed around increasing MTU size to improve throughput for large data transfers in a specific network configuration.
Why candidates choose this
Candidates may find this option tempting because they might associate MTU adjustments with network performance improvements, leading them to mistakenly believe that PoE could also enhance data transmission capabilities in this way.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Common exam traps
A common exam trap is selecting answers that confuse PoE with data-related functions such as encrypting Ethernet frames, compressing voice traffic, or increasing the MTU size. These options may seem plausible because they mention network improvements, but PoE strictly concerns delivering electrical power over Ethernet cables. Misunderstanding this can lead to incorrect answers, as PoE does not alter data frame encryption, voice compression, or packet size limits. Recognizing that PoE’s sole purpose is power delivery helps avoid this trap.
Detailed technical explanation
Power over Ethernet (PoE) is a technology that enables electrical power to be transmitted along with data over standard Ethernet cabling. This eliminates the need for separate power supplies or outlets for devices such as IP phones, wireless access points, and security cameras, simplifying network deployment and reducing cabling complexity. PoE uses specific standards, such as IEEE 802.3af and 802.3at, to safely deliver power while maintaining data integrity. In Cisco networking and the CCNA context, PoE is critical for powering network devices in locations where providing a separate power source is impractical or costly. The switch or midspan device acts as a power sourcing equipment (PSE), detecting if a connected device is PoE-capable before supplying power. This detection prevents damage to non-PoE devices. The decision to supply power is based on negotiation protocols defined in the PoE standards, ensuring compatibility and safe operation. A common exam trap is confusing PoE with features related to data handling, such as encryption, traffic compression, or MTU adjustments. PoE strictly concerns power delivery over Ethernet cables and does not affect data frame encryption, voice compression, or maximum transmission unit sizes. Practically, understanding PoE helps network engineers design efficient infrastructure by reducing the need for additional electrical wiring and enabling flexible device placement.
Key takeaway
Power over Ethernet (PoE) delivers electrical power and data simultaneously over a single Ethernet cable to network devices.
Real-world example
A practitioner preparing for the 200-301 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Power over Ethernet (PoE) delivers electrical power and data simultaneously over a single Ethernet cable to network devices. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Review power over Ethernet (PoE) delivers electrical power and data simultaneously over a single Ethernet cable to network devices., then practise related 200-301 questions on the same topic to reinforce the concept.
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FAQ
Switching and Network Access — This question tests Switching and Network Access — Power over Ethernet (PoE) delivers electrical power and data simultaneously over a single Ethernet cable to network devices..
The correct answer is: To deliver electrical power over Ethernet cabling — PoE allows network devices such as IP phones, wireless access points, and cameras to receive power through the same Ethernet cable used for data.
Review power over Ethernet (PoE) delivers electrical power and data simultaneously over a single Ethernet cable to network devices., then practise related 200-301 questions on the same topic to reinforce the concept.
Power over Ethernet (PoE) delivers electrical power and data simultaneously over a single Ethernet cable to network devices.
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Last reviewed: May 17, 2026
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