To configure the power management mode on PoE ports, use the power inline command in interface configuration mode. To return to the default settings, use the no form of this command.
power inline {auto [max max-wattage] | | consumption max-wattage | never | port {1-event | 2-event | priority value} | static [max max-wattage]}
no power inline {auto | consumption | never | port {1-event | 2-event | priority} | | static}
Syntax Description
auto
|
Enables powered-device detection. If enough power is available, automatically allocates power to the PoE port after device
detection. Allocation is on the first-come, first-serve basis.
|
max
max-wattage
|
(Optional) Limits the power allowed on a port. The range is 4000 to 30000 mW. If no value is specified, the maximum is allowed.
|
never
|
Disables device detection, and disables power to the port.
|
port
|
Configures the power priority of the port.
|
1-event
|
Enables 1-event classification. This is applicable only when the port is in Universal Power over Ethernet-plus (UPOE) mode.
|
2-event
|
Enables 2-event classification.
|
priority value
|
Sets the power priority of the port. In case of a power supply failure, ports configured as lowest priority (7) are turned
off first and ports configured as highest priority (0) are turned off last. The range is 0 to 7.
|
static
|
Enables powered-device detection. Pre-allocates (reserves) power for a port before the switch discovers the powered device.
This action guarantees that the device connected to the interface receives enough power.
|
Command Default
The default is auto (enabled).
The maximum wattage is 30,000 mW.
The default PoE port priority is 0 .
Command Default
Interface configuration (config-if)
Command History
Release
|
Modification
|
Cisco IOS XE Everest 16.6.1
|
This command was introduced.
|
Cisco IOS XE Amsterdam 17.3.1
|
The port priority value was introduced to configure power priority on PoE ports.
|
Usage Guidelines
This command is supported only on PoE-capable ports. If you enter this command on a port that does not support PoE, the following
error message appears:
Device(config)# interface gigabitethernet1/0/1
Device(config-if)# power inline auto
^
% Invalid input detected at '^' marker.
In a switch stack, this command is supported on all ports in the stack that support PoE.
Use the max
max-wattage option to disallow higher-power powered devices. With this configuration, when the powered device sends Cisco Discovery Protocol
messages requesting more power than the maximum wattage, the switch removes power from the port. If the powered-device IEEE
class maximum is greater than the maximum wattage, the switch does not power the device. The power is reclaimed into the global
power budget.
Note
|
The switch never powers any class 0 or class 3 device if the power inline max max-wattage command is configured for less than 30 W.
|
If the switch denies power to a powered device (the powered device requests more power through Cisco Discovery Protocol messages
or if the IEEE class maximum is greater than the maximum wattage), the PoE port is in a power-deny state. The switch generates
a system message, and the Oper column in the show power inline command output shows power-deny.
Use the power inline static max command to give a port high priority. The switch allocates PoE to a port configured in static mode before allocating power
to a port configured in auto mode. The switch reserves power for the static port when it is configured rather than upon device
discovery. The switch reserves the power on a static port even when there is no connected device and whether or not the port
is in a shutdown or in a no shutdown state. The switch allocates the configured maximum wattage to the port, and the amount
is never adjusted through the IEEE class or by Cisco Discovery Protocol messages from the powered device. Because power is
pre-allocated, any powered device that uses less than or equal to the maximum wattage is guaranteed power when it is connected
to a static port. However, if the powered device IEEE class is greater than the maximum wattage, the switch does not supply
power to it. If the switch learns through Cisco Discovery Protocol messages that the powered device needs more than the maximum
wattage, the powered device is shut down.
If the switch cannot pre-allocate power when a port is in static mode (for example, because the entire power budget is already
allocated to other auto or static ports), this message appears: Command rejected: power inline static: pwr not available.
The port configuration remains unchanged.
When you configure a port by using the power inline auto or the power inline static command, the port autonegotiates by using the configured speed and duplex settings. This is necessary to determine the power
requirements of the connected device (whether or not it is a powered device). After the power requirements have been determined,
the switch hardcodes the interface by using the configured speed and duplex settings without resetting the interface.
When you configure a port by using the power inline never command, the port reverts to the configured speed and duplex settings.
If a port has a Cisco-powered device connected to it, you should not use the power inline never command to configure the port. A false link-up can occur, placing the port in an error-disabled state.
Use the power inline port priority command to configure the power priority of a PoE port. Powered devices connected to ports with low port priority are shut
down first in case of a power shortage.
You can verify your settings by entering the show power inline command.
Examples
This example shows how to enable detection of a powered device and to automatically power a PoE port on a switch:
Device> enable
Device# configure terminal
Device(config)# interface gigabitethernet1/0/2
Device(config-if)# power inline auto
This example shows how to configure a PoE port on a switch to allow a class 1 or a class 2 powered device:
Device> enable
Device# configure terminal
Device(config)# interface gigabitethernet1/0/2
Device(config-if)# power inline auto max 7000
This example shows how to disable powered-device detection and to not power a PoE port on a switch:
Device> enable
Device# configure terminal
Device(config)# interface gigabitethernet1/0/2
Device(config-if)# power inline never
This example shows how to set the priority of a PoE port to the highest, so that it will be one of the last ports to be shut
down in case of power supply failure:
Device> enable
Device# configure terminal
Device(config)# interface gigabitethernet1/0/1
Device(config-if)# power inline port priority 0