N10-009 Network Troubleshooting Practice Question

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 is a crossover cable.

  Why it's wrong here

  Modern networking equipment, including switches and IP cameras, incorporates Auto-MDIX (Automatic Medium-Dependent Interface Crossover) technology. This feature automatically detects the wiring configuration of the connected Ethernet cable, whether it's a straight-through or crossover cable, and adjusts the port's transmit and receive pairs accordingly. Consequently, using a crossover cable would not impede connectivity or power delivery to the camera, as the switch port would self-configure to establish a proper link.

  When this WOULD be correct

  A network administrator connects two switches without uplink ports and the link fails; the most likely cause is a crossover cable if auto-MDIX is disabled.

• ✓

  The camera requires 802.3bt (PoE++), but the switch only supports 802.3af (PoE).

  Why this is correct

  This is the most probable cause. An 802.3af (PoE) compliant switch can deliver up to 15.4 watts of power at the port, with 12.95 watts available at the powered device. However, a modern, feature-rich security camera, especially one with pan-tilt-zoom capabilities, heaters, or advanced analytics, often requires the significantly higher power provided by 802.3bt (PoE++), which can supply up to 60W or even 100W at the source. If the camera's power demand exceeds the switch's output capability, the camera will fail to power on or operate reliably.

• ✗

  The port is configured as an access port.

  Why it's wrong here

  The configuration of a switch port as an access port primarily defines its VLAN membership and how it handles untagged data traffic for end devices. This logical layer 2 configuration is entirely distinct and separate from the physical Power over Ethernet (PoE) power delivery mechanism. PoE power negotiation and supply occur at the physical layer (Layer 1) and are independent of the port's VLAN assignment or whether it's configured as an access or trunk port. Therefore, an access port configuration would not prevent a PoE camera from receiving power.

  When this WOULD be correct

  A switch port configured as an access port would be the correct answer if the question described a camera that requires a specific VLAN tag to function (e.g., a VoIP phone needing voice VLAN), and the port was set to trunk mode, causing the camera to not receive the correct VLAN traffic.

• ✗

  The camera is using a passive PoE injector.

  Why it's wrong here

  Passive PoE injectors continuously supply power without any negotiation with the powered device, unlike active IEEE 802.3af/at/bt compliant PoE. While using a mismatched passive injector could indeed cause issues or damage, the question implies the camera is connected directly to a switch, which typically provides active PoE. If a passive injector were incorrectly introduced into an active PoE system, it would bypass the necessary power negotiation, potentially leading to incorrect voltage delivery or non-functionality, but it's not the primary issue when a switch is involved.

  When this WOULD be correct

  A question where a non-PoE switch is used and a passive injector is incorrectly wired or provides insufficient power for the camera, causing it not to power on.

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.

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?”

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