N10-009 Network Implementation Practice Question
A network administrator needs to power IP phones and wireless access points through the Ethernet cable. Which standard should be supported?
⚠ Common exam trap
A common mix-up: candidates confuse the 802.3 family of wired Ethernet standards (which includes PoE) with the 802.11 family of wireless standards (like 802.11ac), leading candidates to mistakenly select a Wi-Fi standard for a power-over-cable requirement.
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
✓
802.3af
The 802.3af standard, also known as Power over Ethernet (PoE), delivers up to 15.4 watts of DC power over twisted-pair Ethernet cabling. This allows devices like IP phones and wireless access points to receive both data and power through a single Ethernet cable, eliminating the need for separate power supplies.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
802.3af
Why this is correct
802.3af is the IEEE standard specifically designed for Power over Ethernet (PoE), enabling network devices like IP phones and wireless access points to receive electrical power and data over a single Ethernet cable. This standard provides up to 15.4 watts of DC power to powered devices (PDs) at the port, significantly simplifying infrastructure by eliminating the need for separate power outlets and cabling near the endpoint devices.
- ✗
802.11ac
Why it's wrong here
802.11ac is an IEEE wireless networking standard that defines very high throughput (VHT) wireless local area networks (WLANs) operating exclusively in the 5 GHz frequency band. It focuses on increasing data rates and efficiency for Wi-Fi communications, utilizing technologies like wider channels and multi-user MIMO. This standard is entirely unrelated to the delivery of electrical power over wired Ethernet cables.
When this WOULD be correct
A question asking which Wi-Fi standard supports high-throughput wireless connections in the 5 GHz band with channel bonding up to 160 MHz would have 802.11ac as the correct answer.
- ✗
802.1X
Why it's wrong here
802.1X is an IEEE standard for port-based network access control, providing an authentication mechanism to devices attempting to connect to a wired or wireless network. It ensures that only authorized users and devices can access network resources by requiring credentials before granting network access. This security protocol is entirely distinct from any mechanism for delivering electrical power to network devices.
When this WOULD be correct
802.1X would be correct in a question about securing network access, such as 'Which standard is used for port-based authentication to control access to a wired or wireless network?'
- ✗
802.3ab
Why it's wrong here
802.3ab is the IEEE standard that defines 1000BASE-T, which specifies Gigabit Ethernet over unshielded twisted-pair (UTP) copper cabling, typically Category 5e or Category 6. Its primary function is to enable data transmission at 1 gigabit per second over distances up to 100 meters. This standard exclusively addresses data signaling and physical layer specifications for high-speed wired networking, not the provision of electrical power.
When this WOULD be correct
A network administrator needs to upgrade a network from Fast Ethernet to Gigabit Ethernet over existing Cat5e cabling. Which standard should be supported?
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.
✓802.3afCorrect answer▾
Why this is correct
802.3af is the IEEE standard specifically designed for Power over Ethernet (PoE), enabling network devices like IP phones and wireless access points to receive electrical power and data over a single Ethernet cable. This standard provides up to 15.4 watts of DC power to powered devices (PDs) at the port, significantly simplifying infrastructure by eliminating the need for separate power outlets and cabling near the endpoint devices.
✗802.11acWrong answer — click to see why▾
Why this is wrong here
802.11ac is a wireless networking standard for Wi-Fi, not a Power over Ethernet (PoE) standard. It does not define power delivery over Ethernet cables.
★ When this WOULD be the correct answer
A question asking which Wi-Fi standard supports high-throughput wireless connections in the 5 GHz band with channel bonding up to 160 MHz would have 802.11ac as the correct answer.
Why candidates choose this
Candidates may confuse 802.11ac (a wireless standard) with 802.3af (a PoE standard) due to similar numbering, or mistakenly think that powering devices over Ethernet is related to Wi-Fi standards.
✗802.1XWrong answer — click to see why▾
Why this is wrong here
802.1X is an authentication protocol for network access control, not a standard for powering devices over Ethernet. The question asks for a standard that provides power over Ethernet, which is addressed by IEEE 802.3af (PoE).
★ When this WOULD be the correct answer
802.1X would be correct in a question about securing network access, such as 'Which standard is used for port-based authentication to control access to a wired or wireless network?'
Why candidates choose this
Candidates may confuse 802.1X with 802.3af because both are IEEE standards related to networking, and the 'X' might be misremembered as a power-related designation.
✗802.3abWrong answer — click to see why▾
Why this is wrong here
802.3ab defines Gigabit Ethernet over copper (1000BASE-T), not Power over Ethernet (PoE). It does not provide power delivery.
★ When this WOULD be the correct answer
A network administrator needs to upgrade a network from Fast Ethernet to Gigabit Ethernet over existing Cat5e cabling. Which standard should be supported?
Why candidates choose this
Candidates may confuse 802.3ab with PoE standards because both involve Ethernet cabling, or mistakenly think 'ab' implies power capabilities.
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?”
Go deeper
Related to this question
Learn chapter
Ethernet Switching and VLANs
Key term
PoE
Power over Ethernet (PoE) is a technology that lets network cables carry electrical power to devices like cameras and phones, so they don't need a separate power outlet.
Key term
RX
RX (Receive / Receiver) is the signal path or hardware component that accepts incoming data from a network medium.
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.