PoE Configuration Guide

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Power monitoring and power policing

Updated: September 15, 2025

Overview

Explains how power monitoring and power policing works and how to configure it.

Power monitoring, also known as power sensing, is the process in which a PoE-capable switch monitors the real-time power consumption of a powered device.

Power monitoring works with Cisco intelligent power management and CDP-based power consumption features to ensure that the PoE port can supply power to a powered device.

Power policing is the process that enables the switch to restrict power usage based on power monitoring. By default, power policing is disabled on all PoE ports.

How power monitoring and power policing works

Workflow

Power monitoring and power policing allow the switch to control the power consumption of a powered device. This is how power monitoring works:

  1. The switch monitors the real-time power consumption of its individual ports.
  2. The switch records the power consumption, including peak power usage. It reports this information through CISCO-POWER-ETHERNET-EXT-MIB.
  3. If power policing is enabled, the switch polices power usage by comparing the real-time power consumption with the maximum power allocated to the powered device. This maximum power value is also known as the cutoff power.
    • If the powered device uses more than the cutoff power, the switch can either turn off the power to the port, or can generate a syslog message and update the LEDs . In this case, the port LED blinks amber, and the switch continues providing power to the powered device based on the device configuration.
    • If error recovery from the PoE error-disabled state is enabled, the switch automatically takes the PoE port out of the error-disabled state after the specified amount of time.
    • If error recovery is disabled, you can manually re-enable the PoE port by using the shutdown and no shutdown interface configuration commands.
  4. If power policing is disabled, no action occurs when the powered device consumes more than the maximum power allocation on the PoE port, which could adversely affect the switch.

Power consumption values for power monitoring and power policing

You can configure the initial power allocation and the maximum power allocation on a port. However, these configured values determine when the switch turns power on or off on the PoE port. The maximum power allocation is not the same as the actual power consumption of the powered device. The cutoff power value that the switch uses for power policing is not equal to the configured power value.

When you manually set the maximum power allocation, you must consider the power loss over the cable from the switch port to the powered device. The cutoff power is the sum of the rated power consumption of the powered device and the worst-case power loss over the cable.

We recommend that you enable power policing when PoE is enabled on your switch.

For example, with a Class 1 switch, if policing is disabled and you set the cutoff-power value by using the power inline auto max 6300 command, in interface configuration mode, the configured maximum power allocation on the PoE port is 6.3 W (6300 mW). The switch provides power to the powered devices on the port if the powered device needs up to 6.3 W. If the CDP power-negotiated value or the IEEE classification value exceeds the configured cutoff value, the switch does not provide power to the powered device. After the switch turns on power on the PoE port, it does not police the real-time power consumption of the powered device. As a result, the powered device can consume more power than the maximum allocated amount, which could adversely affect the switch and other powered devices connected to other PoE ports.

Configure power policing

You can perform this task to police the power usage.

By default, the device monitors the real-time power consumption of powered devices and policing is disabled.

Procedure

1.

enable

Example:

Device> enable

Enables privileged EXEC mode.

Enter your password, if prompted.
2.

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.
3.

interface interface-id

Example:

Device(config)# interface gigabitethernet1/0/4

Specifies the physical port to be configured and enters interface configuration mode.
4.

power inline police [action {log | errdisable}]

Example:

Device(config-if)# power inline police

Configures the device to take one of these actions if the real-time power consumption exceeds the maximum power allocation on the port:

  • power inline police : Shuts down the PoE port, turns off power to it, and puts it in the error-disabled state.

    Note

    You can enable error detection for the PoE error-disabled state by using the errdisable detect cause inline-power global configuration command. You can also enable the timer to recover from the PoE error-disabled state by using the errdisable recovery cause inline-power interval interval global configuration command.

  • power inline police action errdisable : Turns off power to the port if the real-time power consumption exceeds the maximum power allocation on the port.

  • power inline police action log : Generates a syslog message while still providing power to the port.

If you do not enter the action log keywords, the default action shuts down the port and puts the port in the error-disabled state.

5.

exit

Example:

Device(config-if)# exit

Exits interface configuration mode, and returns to global configuration mode.

6.

Choose any one of the following commands:

  • errdisable detect cause inline-power

  • errdisable recovery cause inline-power

  • errdisable recovery interval interval

Example:


Device(config)# errdisable detect cause inline-power
OR
Device(config)# errdisable recovery cause inline-power
OR
Device(config)# errdisable recovery interval 100

(Optional) Enables error recovery from the PoE error-disabled state, and configures the PoE recovery mechanism variables.

  • errdisable detect cause inline-power : Enables the switch to detect errors related to PoE that would cause a port to enter an error-disabled state. When enabled, if a PoE-related issue occurs on a port such as a connected device attempts to draw more power than allocated or supported by the port, the switch will place that port into an err-disabled state.

  • errdisable recovery cause inline-power : Enables the automatic recovery mechanism for ports that have been placed in an err-disabled state specifically due to an inline-power error. Without this command, an administrator would need to manually re-enable the port by issuing shutdown followed by no shutdown commands on the interface.

  • errdisable recovery interval interval : Sets the time, in seconds, that the switch will wait before attempting to automatically re-enable a port that is in an err-disabled state.

    The interval range is 30 to 86400.

    By default, the recovery interval is 300 seconds.

7.

exit

Example:

Device(config)# exit

Returns to privileged EXEC mode.
8.

Choose any one of the following:

  • show power inline police

  • show errdisable recovery

Example:


Device# show power inline police
OR
Device# show errdisable recovery

Displays the power-monitoring status, and verifies the error recovery settings.

9.

copy running-config startup-config

Example:

Device# copy running-config start-up config

(Optional) Saves your entries in the configuration file.