PoE Flashcards
What are the different PoE modes and wattage outputs?
PoE mode | Naming | Output
Cisco Inline Power | ILP | 7W
IEEE 802.3af | PoE | 15.4W
IEEE 802.3at | PoE+ | 25.5W
Cisco Universal PoE | UPoE | 60W
IEEE 802.3bt | PoE++ | 96W
What is a network device (switch) that provides the power
Power Sourcing Equipment (PSE)?
What is a network device (phone / access-point / etc.) that requires power
Powered Device (PD)
What are the 2 power over ethernet methods?
Cisco ILP and 802.3af
How many 802.3af power classes are there?
5 (0-4 with 4 being the highest)
What is the default 802.3af power class and its use?
if the switch or the powered device doesn’t suport power class discovery
How does 802.3af do power discovery?
sends a voltage across the receive pairs to detect a 25k ohm resistance
How does ILP do power discovery?
sends a test tone on the transmit pair. If a device is detected, CDP is used to narrow down the power class.
What ILP mode are all ports in by default?
auto mode
How many classes of PoE are there, what are they, and what is the default class?
There are 5 classes, 0-4, and 0 is default.
What command displays Power over Ethernet information about a switch?
(exec)show power inline
