A PoE-capable switch port automatically supplies power to one of these connected devices if the switch senses that there is no power on the circuit:
- a Cisco pre-standard powered device (such as a Cisco IP Phone or a Cisco Aironet Access Point)
- an IEEE 802.3af-compliant powered device
A powered device can receive redundant power when it is connected to a PoE switch port and to an AC power source. The device does not receive redundant power when it is only connected to the PoE port.
Configuring a Power Management Mode on a PoE Port
//Enables privileged EXEC mode. Enter your password if prompted.
Switch# configure terminal
//Enters global configuration mode
Switch(config)# interface gigabitethernet2/0/1
//Specifies the physical port to be configured, and enters interface configuration mode.
Switch(config-if)# power inline auto
//Configures the PoE mode on the port. The keywords have these meanings:
auto—Enables powered-device detection. If enough power is available, automatically allocates power to the PoE port after device detection. This is the default setting.
max max-wattage—Limits the power allowed on the port. If no value is specified, the maximum is allowed.
max max-wattage—Limits the power allowed on the port. The range is 4000 to 30000 mW. If no value is specified, the maximum is allowed.
never —Disables device detection, and disable power to the port.
static—Enables powered-device detection. Pre-allocate (reserve) power for a port before the switch discovers the powered device. The switch reserves power for this port even when no device is connected and guarantees that power will be provided upon device detection.
//Returns to privileged EXEC mode.
Switch# show power inline
//Displays PoE status for a switch or a switch stack, for the specified interface, or for a specified stack member.
Switch# copy running-config startup-config
//Saves your entries in the configuration file.