Use the Configure > PoE page to view information about the PoE ports and to configure the power settings. Note: PoE and PoE+ commands are supported when power is connected to a switch with either a built-in PoE power connector or a PoE expansion module. The PoE and PoE+ features are applicable to Cisco IOS Release 15.0(2)EY and later. Ensure that the PoE power supply is connected at the time of IOS boot as it is a prerequisite for power-on-self-test (POST) to pass before enabling the power inline function. Procedures Back to the top At the top of the configuration window, an interactive image provides information about the front panel of the device. When you position your mouse pointer over a PoE port on this image, the following information appears: interface number, status, and PoE status. If there is a link on the PoE port, the description also includes the speed and the duplex mode. Back to the top Select a connected module to see the following information: Total Power Supported, Total Power Used, and Total Power Available. The values are in watts. Total Power Supported: If you want to limit the total PoE power budget, enter an appropriate value, based on the power source. The valid range is from 4 watts to 130 watts. When you save this setting, it changes the total PoE power budget and resets the powered devices to meet the new budget. Caution: A mismatch between the Total Power Supported and the power supply may cause damage to the switch. Take care not to oversubscribe the power supply. - If you intend to connect the switch to a power supply that allows more wattage than configured, first change the power supply and then enter the Total Power Supported.
- If you intend to connect the switch to a power supply that allows less wattage than configured, first change the Total Power Supported to an appropriate value and then change the power supply.
Back to the top This table displays the following information for each PoE port: the administrative mode (auto, static, or disabled), the operational status (on or off), the allocated power, the maximum power, the override power, the connected device if any, and the power classification of the device. All values are in watts. IEEE classifications are described below. - Class 0: Up to 15.4 W (0.44-12.95 W at the PD; default classification)
- Class 1: Up to 4 W (0.44-3.84 W at the PD)
- Class 2: Up to 7 W (3.84-6.49 W at the PD)
- Class 3: Up to 15.4 W (6.49-12.95 W at the PD)
"Yes" in the Override column indicates that the port is configured with a default power setting that overrides the IEEE classification. This setting can be changed by using the CLI to enter the power inline consumption default wattage command. To reset the port to use power specified by the IEEE classification of a powered device, enter the no power inline consumption default command. To configure the power settings for an interface, click the Edit button. Back to the top After clicking the Edit button in the Interface table, you can configure the duplex mode and the power settings for the selected PoE port. Note: When you make PoE configuration changes, the selected port drops power. Depending on the new configuration, the state of the other PoE ports, and the state of the power budget, the port might not be powered up again. For example, if port 1 is in the auto and on state, and you configure it for static mode, the switch removes power from port 1, detects the powered device, and repowers the port. If port 1 is in the auto and on state and you configure it with a maximum wattage of 10 watts, the switch removes power from the port and then redetects the powered device. The switch repowers the port only if the powered device is a Class 1, Class 2, or a Cisco-only powered device. For most situations, the default configuration (auto mode) works well, providing plug-and-play operation. No further configuration is required. However, you can customize the settings to meet your needs. For example, to give a PoE port higher power priority, set the administrative mode to static and allocate the power to be used. To disallow high-power devices on a port, set the administrative mode to auto and specify a power limit. - Auto mode enables the detection of powered-devices and automatically allocates power to the PoE port if a device is connected. This setting is selected by default. To limit the power used by this port, adjust the Max Power setting. The valid ranges are 4 to 15.4 watts for a PoE port and 4 to 30 watts for a PoE+ port. The Power Allocated field displays the number of watts currently allocated to this port.
- Static mode reserves power for this port even when no device is connected, to guarantee that power will be provided upon device detection. You might also choose static mode to prioritize a port, since the switch allocates power to a static mode ports before it allocates power to auto mode ports. To set the Power Allocated to this port, enter a value in watts. The Max Power field displays the maximum power in watts.
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