Cisco WS-C3560E-48PD-SF Command Reference - Page 343

Chapter 2 Catalyst 3560 Switch Cisco IOS Commands power inline If the switch denies power to a powered device (the powered device requests more power through CDP 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 user EXEC command output shows power-deny. Use the power inline static max max-wattage 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 CDP 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 CDP 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 interface configuration 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 on the port, placing it into an error-disabled state. Caution In releases earlier than Cisco IOS Release 12.2(20)SE1, power was sometimes still applied to a PoE port even after a powered device was removed. This could cause damage to a nonpowered device when it was later connected to that port. Make sure that your switch is running Cisco IOS Release 12.2(20)SE1 or later. Examples This example shows how to enable detection of a powered device and to automatically power a PoE port: Switch(config)# interface fastethernet0/2 Switch(config-if)# power inline auto This example shows how to configure a PoE port to allow a Class 1 or a Class 2 powered device: Switch(config)# interface fastethernet0/2 Switch(config-if)# power inline auto max 7000 This example shows how to disable powered-device detection and to not power a PoE port: Switch(config)# interface fastethernet0/2 Switch(config-if)# power inline never You can verify your settings by entering the show power inline user EXEC command. 78-16405-05 Catalyst 3560 Switch Command Reference 2-311