2. Power over Ethernet (PoE) and its impact
on the CIO portfolio
PoE is the transfer of electrical power, along with
data, to remote devices over standard data cables
in an Ethernet network (Cat3/Cat5/Cat5e/Cat6 ).
3. IEEE802.3af-2003 Specifications
• The original IEEE 802.3af-2003 standard version
of PoE supplies up to 15.4 W of DC power
(minimum 44 VDC and 350 mA) to each device.
• Only 12.95 W is assured to be available at the
powered device (PD) as some power is
dissipated in the cable.
4. IEEE802.3at-2009 Specifications
• Cabling: CAT5E required
• Power Feeding: 2-pairs and 4-pairs possible
– Focus on 2-pairs Medium Power: PSE 30W output, PD
25.5W input
– 4-pairs High Power should be based on 2x2-pairs: PSE 60W
output, PD 51W input
• IEEE 802.3az Energy-Efficient Ethernet
– savings upwards of 3 watts per link