Which standard governs power delivery over Ethernet but is not a signaling protocol?

Which standard governs power delivery over Ethernet but is not a signaling protocol?

• A. Quality of Service
• B. Power over Ethernet
• C. Link Aggregation Control Protocol
• D. VLAN tagging

Answer: (B)

Power over Ethernet is the standard that governs how DC power is delivered over Ethernet cables. It enables devices like IP phones or cameras to be powered directly from the network switch or an PoE injector, eliminating the need for separate power adapters. It isn’t a signaling protocol because its primary role is delivering power, not exchanging control messages or managing network behavior. The power negotiation steps in PoE—detection and classification—are about ensuring safe and compatible power delivery, not signaling data paths. By comparison, QoS handles traffic prioritization, LACP is used to negotiate and maintain link aggregation, and VLAN tagging is a method to separate traffic into VLANs. Thus PoE is the standard that fits the description.

Power over Ethernet is the standard that governs how DC power is delivered over Ethernet cables. It enables devices like IP phones or cameras to be powered directly from the network switch or an PoE injector, eliminating the need for separate power adapters. It isn’t a signaling protocol because its primary role is delivering power, not exchanging control messages or managing network behavior. The power negotiation steps in PoE—detection and classification—are about ensuring safe and compatible power delivery, not signaling data paths. By comparison, QoS handles traffic prioritization, LACP is used to negotiate and maintain link aggregation, and VLAN tagging is a method to separate traffic into VLANs. Thus PoE is the standard that fits the description.