Cisco CCNA (200-301)Network FundamentalsEasy
A network administrator needs to provide power to a new wireless access point (AP) located in a ceiling, where running a separate electrical outlet is impractical. The AP supports IEEE 802.3at. Which technology would be most suitable to power this AP over the existing Ethernet cabling?
- APower over Ethernet (PoE)
- BUniversal Serial Bus (USB) Power
- CPowerline Communication (PLC)
- DFiber Optic Powering
Show answer & explanationAnswer & explanation
Correct answer: A. Power over Ethernet (PoE)
Power over Ethernet (PoE) is specifically designed to deliver electrical power along with data over standard Ethernet cable. Since the AP supports IEEE 802.3at (PoE+), it can be powered directly from a PoE-enabled switch or injector, eliminating the need for a separate power outlet.
Why the other options are wrong
- B. USB power is for small devices and short distances, not typically for APs over Ethernet infrastructure.
- C. PLC transmits data over electrical power lines, not power over Ethernet cables.
- D. Fiber optic cables transmit light for data, they do not carry electrical power.
Power over Ethernet (PoE)
A technology that allows network cables to carry electrical power along with data, eliminating the need for separate power outlets for networked devices.
- Defined by IEEE 802.3af (PoE), 802.3at (PoE+), and 802.3bt (PoE++).
- Simplifies installation of devices like IP phones, access points, and security cameras.
- Requires a Power Sourcing Equipment (PSE) like a PoE switch or injector.
Memory trick: PoE is Power over Ethernet, PLC is Powerline, USB is Small, Fiber is Light.