What happens when an active Ethernet switch fails to sense a PoE device on a port?

What happens when an active Ethernet switch fails to sense a PoE device on a port?

• A. It disables the port to which the line is attached.
• B. It powers the port at maximum PoE.
• C. It switches traffic to another port.
• D. It negotiates PoE with all connected devices.

Answer: (A)

PoE is only supplied after the switch detects a compatible device on that port. If the switch fails to sense a PoE device, it won’t apply power to that port and effectively disables the PoE portion of that link. This protects the network from powering non-PoE devices and stays within the switch’s power budget.

The other options don’t fit because there’s no reason to power the port at all without a detected PD, there’s no automatic traffic shifting to other ports just because PoE isn’t detected, and there’s no negotiation with all devices when no PoE device has been identified.