N10-009 Network Implementation Practice Question
A network engineer needs to install 15 wireless access points that each require 25W of power. The available switch provides PoE+ (802.3at) with a total power budget of 740W. The engineer also needs to connect 10 IP cameras that each require 12W. Which of the following should the engineer verify before proceeding with the installation?
⚠ Common exam trap
The trap here is that candidates may overlook the simple power budget calculation and instead focus on irrelevant details like manufacturer compatibility or cable length limits, but the core requirement is ensuring the total wattage does not exceed the switch's PoE budget.
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
✓
The total power consumption of all devices does not exceed the switch's power budget.
The total power required is 15 APs × 25W + 10 cameras × 12W = 375W + 120W = 495W, which is well below the switch's 740W PoE+ budget. However, the engineer must verify that the cumulative power draw does not exceed the budget, as exceeding it would cause some ports to be denied power or shut down. This is the fundamental prerequisite for any PoE deployment.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The total power consumption of all devices does not exceed the switch's power budget.
Why this is correct
This is a critical consideration for any Power over Ethernet (PoE) deployment. Each PoE switch has a finite power budget, representing the maximum total wattage it can supply across all its PoE-enabled ports. If the combined power requirements of all connected Powered Devices (PDs), such as 15 wireless access points each needing 25W (totaling 375W), exceed this budget, the switch will be unable to provide sufficient power to all devices, leading to some devices failing to power on or operate reliably. Therefore, calculating the total power draw and ensuring it is less than or equal to the switch's advertised power budget is a fundamental design requirement.
- ✗
The switch supports LLDP-MED for power negotiation.
Why it's wrong here
While Link Layer Discovery Protocol - Media Endpoint Discovery (LLDP-MED) is an extension that allows for more granular power negotiation between a Power Sourcing Equipment (PSE) switch and a Powered Device (PD), it is not a mandatory requirement for basic PoE or PoE+ functionality. Standard PoE (IEEE 802.3af) and PoE+ (IEEE 802.3at) devices can operate without LLDP-MED, as they typically use hardware-based power classification or default to maximum power delivery if classification is not explicitly negotiated. Its absence does not prevent the access points from receiving power, although its presence could optimize power allocation and provide more detailed device information.
When this WOULD be correct
A question where the switch's power budget is sufficient but the engineer needs to ensure proper power allocation and prioritization among devices, such as when connecting IP phones and APs that support LLDP-MED for dynamic power negotiation.
- ✗
All PoE devices are from the same manufacturer.
Why it's wrong here
Power over Ethernet (PoE) is governed by IEEE 802.3 standards (e.g., 802.3af, 802.3at, 802.3bt), which ensure interoperability between compliant devices from different manufacturers. As long as both the Power Sourcing Equipment (PSE) switch and the Powered Device (PD) access points adhere to the same PoE standard, they will function together seamlessly, regardless of their brand. Requiring devices from the same manufacturer would contradict the fundamental purpose of standardization, which is to promote open ecosystems and prevent vendor lock-in, allowing for flexibility in network design.
When this WOULD be correct
In a scenario where the exam asks about ensuring compatibility for advanced features like PoE scheduling or per-port power prioritization that are vendor-specific, verifying all devices are from the same manufacturer would be necessary.
- ✗
The cable length does not exceed 150 meters.
Why it's wrong here
The IEEE 802.3 Ethernet standard, which includes Power over Ethernet (PoE), specifies a maximum cable segment length of 100 meters (approximately 328 feet) for reliable data transmission and power delivery over twisted-pair copper cabling. Exceeding this 100-meter limit, even to 150 meters, would result in significant signal degradation and increased resistance. This leads to substantial power loss and potential inability to power the devices adequately, in addition to compromising data integrity and network performance. Therefore, 100 meters is the critical maximum for reliable operation, not 150 meters.
When this WOULD be correct
This option would be correct if the question were: 'A network engineer needs to install PoE devices 180 meters from the switch. Which of the following should the engineer verify?' In that scenario, the maximum cable length (100m for standard Ethernet) would be a critical constraint.
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.
✓The total power consumption of all devices does not exceed the switch's power budget.Correct answer▾
Why this is correct
This is a critical consideration for any Power over Ethernet (PoE) deployment. Each PoE switch has a finite power budget, representing the maximum total wattage it can supply across all its PoE-enabled ports. If the combined power requirements of all connected Powered Devices (PDs), such as 15 wireless access points each needing 25W (totaling 375W), exceed this budget, the switch will be unable to provide sufficient power to all devices, leading to some devices failing to power on or operate reliably. Therefore, calculating the total power draw and ensuring it is less than or equal to the switch's advertised power budget is a fundamental design requirement.
✗The switch supports LLDP-MED for power negotiation.Wrong answer — click to see why▾
Why this is wrong here
The primary concern is whether the total power draw (15 APs × 25W + 10 cameras × 12W = 495W) exceeds the switch's 740W budget. LLDP-MED is used for power negotiation but is not a prerequisite for PoE+ operation; devices can draw power without it.
★ When this WOULD be the correct answer
A question where the switch's power budget is sufficient but the engineer needs to ensure proper power allocation and prioritization among devices, such as when connecting IP phones and APs that support LLDP-MED for dynamic power negotiation.
Why candidates choose this
Candidates may confuse power negotiation protocols (LLDP-MED) with basic power delivery requirements, thinking that without LLDP-MED the devices cannot draw power correctly, when in fact PoE+ works without it.
✗All PoE devices are from the same manufacturer.Wrong answer — click to see why▾
Why this is wrong here
The question is about verifying power budget compliance; manufacturer homogeneity is irrelevant to power delivery and does not affect whether the switch can supply the required wattage.
★ When this WOULD be the correct answer
In a scenario where the exam asks about ensuring compatibility for advanced features like PoE scheduling or per-port power prioritization that are vendor-specific, verifying all devices are from the same manufacturer would be necessary.
Why candidates choose this
Candidates may mistakenly think that mixing manufacturers causes power negotiation issues, or they confuse vendor lock-in with fundamental power budget calculations.
✗The cable length does not exceed 150 meters.Wrong answer — click to see why▾
Why this is wrong here
The question asks about verifying power consumption against the switch's power budget, not cable length. The total power required is 15×25W + 10×12W = 495W, which is under the 740W budget, so power is sufficient. Cable length limits (100m for Ethernet) are unrelated to this verification.
★ When this WOULD be the correct answer
This option would be correct if the question were: 'A network engineer needs to install PoE devices 180 meters from the switch. Which of the following should the engineer verify?' In that scenario, the maximum cable length (100m for standard Ethernet) would be a critical constraint.
Why candidates choose this
Candidates may confuse PoE power delivery with cable length limitations, thinking that longer cables reduce power delivery or that PoE has a 150m limit, but standard Ethernet is limited to 100m regardless of PoE.
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
Wireless Standards and Configuration
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
Switch
A switch is a networking device that connects devices on a local area network and uses MAC addresses to forward data only to the intended recipient.
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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.