220-1101 Networking Practice Question
A network technician is installing a new IP security camera that requires Power over Ethernet (PoE) IEEE 802.3af. The technician runs a new Cat6 Ethernet cable between a PoE switch port and the camera. The switch is PoE-enabled and configured to supply power. When the camera is connected, it does not power on. The technician tests the cable with a continuity tester, and all eight wires pass. Which of the following is the most likely cause of the issue?
⚠ Common exam trap
Watch out — candidates often assume a cable or power mismatch is the issue, but they overlook the simple administrative state of the switch port, which is a common Cisco exam trick where a port passes all physical tests but is logically disabled.
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 switch port is administratively disabled in the switch configuration.
The most likely cause is that the switch port is administratively disabled. Even though the switch is PoE-enabled and the cable passes continuity, if the port is in a shutdown state (e.g., via the 'shutdown' command in Cisco IOS), it will not provide power or data to the camera. The technician should verify the port status with 'show interfaces' or 'show running-config' and enable it with 'no shutdown'.
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 cable run exceeds the maximum length for PoE (100 meters).
Why it's wrong here
While Ethernet links have a maximum channel length of 100 meters, a continuity tester verifies wire mapping and shorts, not distance or attenuation. If the cable were over 100 m, the camera's link would likely fail entirely, and PoE voltage drop would be symptomatic but not the only cause. The scenario states a continuity test passed, which does not rule out length, but because the camera requires 802.3af and the switch provides it, a disabled port is a more specific and verifiable cause. Moreover, exceeding length is a physical-layer issue that would affect data and power, but the question points to a configuration error rather than an installation-measurement error.
When this WOULD be correct
A technician installs a PoE device 120 meters from the switch, and the device does not power on. The cable tests good, but PoE standards limit cable runs to 100 meters. In this scenario, the excessive cable length would be the cause.
- ✓
The switch port is administratively disabled in the switch configuration.
Why this is correct
A switch port that is administratively shut down does not forward frames and, crucially, does not apply PoE power. The camera's continuity test only verifies physical wiring; the port's operational state is a logical condition that must be checked via 'show interfaces status'. Even with a perfect cable, the camera will not boot if the port remains in shutdown, because the PSE circuitry is inactive. This is the most common and easily overlooked cause during initial camera installation, as the port appears connected but is configured off by default or by prior administrative action.
- ✗
The camera requires PoE+ (802.3at) and will not work with standard PoE.
Why it's wrong here
The camera is specified to require 802.3af (standard PoE), which the switch explicitly provides. A device that demands 802.3at (PoE+) draws up to 30 watts, while 802.3af provides only 15.4 watts; if that were the case, the camera would not power on with standard PoE. Since the scenario states the camera's requirement is 802.3af, the PoE power budget is sufficient, and the issue is not a mismatch between PoE classes. This eliminates the power specification as the root cause, unlike an administratively disabled port that directly cuts all power and data.
When this WOULD be correct
This option would be correct if the question stated that the camera requires PoE+ (802.3at) and the switch only supports standard PoE (802.3af). For example: 'A technician installs a new IP camera that requires PoE+ (802.3at) on a switch that only supports PoE (802.3af). The camera does not power on. What is the most likely cause?'
- ✗
The cable is terminated with T568A on one end and T568B on the other.
Why it's wrong here
Terminating one end with T568A and the other with T568B creates a crossover cable, which still passes continuity and provides PoE on the same physical pins. Modern network equipment, including most switches and cameras, incorporates auto-MDIX to automatically detect and compensate for crossover wiring, so data connectivity remains functional. PoE is pin-agnostic with respect to wiring standards—power is delivered on the unused pairs in 10/100BASE-T or on the data pairs in Gigabit, and both T568A/B preserve those pairs. Therefore, this wiring variation would not prevent the camera from receiving power or establishing a link, making it an incorrect explanation for the failure.
When this WOULD be correct
This would be correct in a scenario where two switches are connected directly without auto-MDIX, and the link fails due to a straight-through cable. The question would specify that the cable is used for data-only communication between two similar devices.
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 220-1101 exam frequently reuses these exact scenarios with slightly different constraints.
✓The switch port is administratively disabled in the switch configuration.Correct answer▾
Why this is correct
A switch port that is administratively shut down does not forward frames and, crucially, does not apply PoE power. The camera's continuity test only verifies physical wiring; the port's operational state is a logical condition that must be checked via 'show interfaces status'. Even with a perfect cable, the camera will not boot if the port remains in shutdown, because the PSE circuitry is inactive. This is the most common and easily overlooked cause during initial camera installation, as the port appears connected but is configured off by default or by prior administrative action.
✗The cable run exceeds the maximum length for PoE (100 meters).Wrong answer — click to see why▾
Why this is wrong here
The cable run is not the issue because the continuity test passed and the distance is not specified as exceeding 100 meters. The problem is that the switch port is administratively disabled, which prevents power delivery regardless of cable length.
★ When this WOULD be the correct answer
A technician installs a PoE device 120 meters from the switch, and the device does not power on. The cable tests good, but PoE standards limit cable runs to 100 meters. In this scenario, the excessive cable length would be the cause.
Why candidates choose this
Candidates know that PoE has a 100-meter distance limit and may assume that any connectivity issue is due to cable length, overlooking the possibility of a disabled switch port.
✗The camera requires PoE+ (802.3at) and will not work with standard PoE.Wrong answer — click to see why▾
Why this is wrong here
The camera requires PoE (IEEE 802.3af), not PoE+, so power compatibility is not an issue. The switch is PoE-enabled and configured to supply power, so the camera should receive adequate power if the port is active.
★ When this WOULD be the correct answer
This option would be correct if the question stated that the camera requires PoE+ (802.3at) and the switch only supports standard PoE (802.3af). For example: 'A technician installs a new IP camera that requires PoE+ (802.3at) on a switch that only supports PoE (802.3af). The camera does not power on. What is the most likely cause?'
Why candidates choose this
Candidates may confuse PoE standards and assume that any PoE device will work with any PoE switch, or they may misread the question and think the camera requires PoE+ when it actually requires standard PoE.
✗The cable is terminated with T568A on one end and T568B on the other.Wrong answer — click to see why▾
Why this is wrong here
A T568A/T568B mismatch (crossover cable) would not prevent PoE power delivery because PoE uses pairs 1-2 and 3-6 for power, and a crossover cable still connects these pairs correctly. The continuity test passed, indicating proper connectivity.
★ When this WOULD be the correct answer
This would be correct in a scenario where two switches are connected directly without auto-MDIX, and the link fails due to a straight-through cable. The question would specify that the cable is used for data-only communication between two similar devices.
Why candidates choose this
Candidates may confuse wiring standards with PoE requirements, thinking that any mismatch disrupts power delivery, or they may recall that crossover cables can cause issues in some network connections.
Analysis generated from the official 220-1101blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1101 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 220-1101 exam.