Installation guide

Initial Configuration
2-10
2
Configuring Power over Ethernet
This switch supports the IEEE 802.3af Power-over-Ethernet (PoE) standard that
enables DC power to be supplied to attached devices over the wire pairs in the
connecting Ethernet cable. Any 802.3af compliant device attached to a port can
directly draw power from the switch over the Ethernet cable without requiring its own
separate power source. This capability gives network administrators centralized
power control for devices such as IP phones and wireless access points, which
translates into greater network availability.
A maximum PoE power budget for the switch (power available to all switch ports)
can be defined so that power can be centrally managed, preventing overload
conditions at the power source. If the power demand from devices connected to the
switch exceeds the power budget setting, the switch uses port power priority
settings to limit the supplied power.
In the example below, the power mainpower maximum allocation CLI command
is used to set the PoE power budget for the switch. (Range: 37 - 180 watts). If
devices connected to the switch require more power than the switch budget, the port
power priority settings are used to control the supplied power. See “Setting a Switch
Power Budget” on page 3-156 for details.
PoE is enabled for all ports by default. Power can be disabled for a port by using the
no form of the power inline CLI command, as shown in the example below.
Console(config)#power mainpower maximum allocation 180 4-206
Console(config)#
Console(config)#interface ethernet 1/2 4-182
Console(config-if)#no power inline 4-207
Console(config-if)#