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Catalyst 2960 and 2960-S Switch Software Configuration Guide
OL-8603-09
Chapter 12 Configuring Interface Characteristics
Configuring Ethernet Interfaces
the actual amount of power needed. If the powered device reports a higher class than its actual
consumption or does not support power classification (defaults to Class 0), the switch can power fewer
devices because it uses the IEEE class information to track the global power budget.
By using the power inline consumption wattage configuration command, you can override the default
power requirement specified by the IEEE classification. The difference between what is mandated by the
IEEE classification and what is actually needed by the device is reclaimed into the global power budget
for use by additional devices. You can then extend the switch power budget and use it more effectively.
For example, if the switch budgets 15,400 milliwatts on each PoE port, you can connect only 24 Class 0
powered devices. If your Class 0 device power requirement is actually 5000 milliwatts, you can set the
consumption wattage to 5000 milliwatts and connect up to 48 devices. The total PoE output power
available on a 24-port or 48-port switch is 370,000 milliwatts.
Caution You should carefully plan your switch power budget and make certain not to oversubscribe the power
supply.
Note When you manually configure the power budget, you must also consider the power loss over the cable
between the switch and the powered device.
When you enter the power inline consumption default wattage or the no power inline consumption
default global configuration command, or the power inline consumption wattage or the no power
inline consumption interface configuration command this caution message appears:
%CAUTION: Interface
interface-id
: Misconfiguring the 'power inline consumption/allocation'
command may cause damage to the switch and void your warranty. Take precaution not to
oversubscribe the power supply.
It is recommended to enable power policing if the switch supports it.
Refer to documentation.
If the power supply is over-subscribed to by up to 20 percent, the switch continues to operate but its
reliability is reduced. If the power supply is subscribed to by more than 20 percent, the short-circuit
protection circuitry triggers and shuts the switch down.
For more information about the IEEE power classifications, see the “Power over Ethernet Ports” section
on page 12-5.
Beginning in privileged EXEC mode, follow these steps to configure the amount of power budgeted to a
powered device connected to each PoE port on a switch:
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
no cdp run (Optional) Disable CDP.
Step 3
power inline consumption default
wattage
Configure the power consumption of powered devices connected to each
the PoE port on the switch.
The range for each de vice is 4000 to 15400 milliwatts on a Catalyst 2960
switch, and 4000 to 30000 milliwatts on a Catalyst 2960-S switch. The
default is 15400 milliwatts on a Catalyst 2960 switch, and 30000
milliwatts on a Catalyst 2960-S switch.
Note When you use this command, we recommend you also enable
power policing.