Question 1easymultiple choice
Full question →easymultiple choiceObjective-mapped
What is the purpose of Power over Ethernet (PoE)?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
To encrypt Ethernet frames
PoE has nothing to do with frame encryption.
B
Best answer
To deliver electrical power over Ethernet cabling
Correct. PoE supplies power over Ethernet cabling.
C
Distractor review
To compress voice traffic on a LAN
PoE does not compress traffic.
D
Distractor review
To increase the maximum IPv4 MTU
PoE does not change the MTU.
Common exam trap
Common exam trap: answer the scenario, not the keyword
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.
Technical deep dive
How to think about this question
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.
KKey Concepts to Remember
- Power over Ethernet (PoE) delivers electrical power and data simultaneously over a single Ethernet cable to network devices.
- PoE uses standards like IEEE 802.3af and 802.3at to negotiate and safely supply power from switches or midspan devices to powered devices.
- A Cisco switch acting as Power Sourcing Equipment (PSE) detects if a connected device supports PoE before supplying power to prevent damage.
- PoE simplifies network deployment by eliminating the need for separate power outlets for devices such as IP phones and wireless access points.
- PoE does not modify Ethernet frame encryption, voice traffic compression, or the maximum transmission unit (MTU) size on the network.
- The negotiation process in PoE ensures only compatible devices receive power, maintaining network stability and device safety.
- PoE enables flexible placement of network devices in locations without nearby electrical power sources, enhancing network design options.
- Understanding PoE helps avoid confusion with unrelated network functions like encryption or traffic optimization in Cisco exams.
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.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
Power over Ethernet (PoE) delivers electrical power and data simultaneously over a single Ethernet cable to network devices.
What is the correct answer to this question?
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.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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