Cisco Systems 4500 Power Management Modes

11-3
Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 11 Configuring Power over Ethernet Power Management Modes
Power Management Modes
If your switch has a module capable of providing PoE to end stations, you can set each interface on the
module to automatically detect and apply PoE if the end station requires power.
The Catalyst 4500 series switch has three PoE modes:
• auto—PoE interface. The supervisor engine directs the switching module to power up the interface
only if the switching module discovers the phone and the switch has enough power. You can specify
the maximum wattage that is allowed on the interface. If you do not specify a wattage, then the
switch delivers no more than the hardware-supported maximum value. This mode has no effect if
the interface is not capable of providing PoE.
• static—High priority PoE interface. The supervisor engine preallocates power to the interface, even
when nothing is connected, guaranteeing that power exists for the interface. You can specify the
maximum wattage that is allowed on the interface. If you do not specify a wattage, then the switch
preallocates the hardware-supported maximum value. If the switch does not have enough power for
the allocation, the command fails. The supervisor engine directs the switching module to power up
the interface only if the switching module discovers the powered device.
• never—Data interface only The supervisor engine never powers up the interface, even if an
unpowered phone is connected. This mode is only needed when you want to make sure power is
never applied to a PoE-capable interface.
The switch can measure the actual PoE consumption for an 802.3af-compliant PoE module, and displays
this in the show power module command.
PoE consumption cannot be measured on the WS-X4148-RJ45V PoE module. For all PoE calculations,
the PoE consumption on this module is presumed to be equal to its administrative PoE.
For more information, see the “Displaying the PoE Consumed by a Module” section on page 11-8.
For most users, the default configuration of “auto” works well, providing plug-and-play capability. No
further configuration is required. However, to make an interface higher priority or data only , or to specify
a maximum wattage, perform this task:
Command Purpose
Step 1 Switch(config)# interface {fastethernet |
gigabitethernet} slot/port Selects the interface to configure.
Step 2 Switch(config-if)# power inline {auto [max
milli-watts] | never | static [max
milli-watts]}
The auto keyword sets the interface to automatically detect
and supply power to the powered device. it is the default
configuration.
The static keyword sets the interface to higher priority than
auto.
If necessary, use the max keyword to specify the maximum
wattage allowed on the interface (4000 to 15400 milliwatts
for most switching modules. As of Cisco IOS Release
12.2(44)SG, the WS-X4648-RJ45V+E can support up to 30
W available per-port and the WS-X4648-RJ45V-E supports
up to 20 W. For more information, see “Enhanced Power PoE
Support on the E-Series Chassis” on page 15).
Use the never keyword to disable detection and power for
the PoE capable interface.