Rockwell ArmorStratix 5700 series, Инструкция по эксплуатации

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Rockwell Automation Publication 1783-UM007F-EN-P - September 2016 317
Configure Switch Features Chapter 7
If enough power is available for all powered devices that are connected
to the switch, power is turned on to all devices. If there is not enough
power to accommodate all connected devices and if a device is
reconnected while other devices are waiting for power, it cannot be
determined which devices are granted or are denied power.
If granting power exceeds the system power budget, the switch denies
power, verifies that power to the port is turned off, generates a syslog
message, and updates the status indicators. After power has been denied,
the switch periodically rechecks the power budget and continues to
attempt to grant the request for power.
If a device being powered by the switch is then connected to wall power,
the switch can continue to power the device. The switch can continue to
report that it is still powering the device whether the device is being
powered by the switch or receiving power from an AC power source.
If a powered device is removed, the switch automatically detects the
disconnect and removes power from the port. You can connect a
nonpowered device without damaging it.
You can specify the maximum wattage that is allowed on the port. If the
IEEE-class maximum wattage of the powered device is greater than the
configured maximum value, the switch does not provide power to the
port. If the switch powers a Cisco end device, but the device later
requests through CDP messages more than the configured maximum
value, the switch removes power to the port. The power that was
allocated to the powered device is reclaimed into the global power
budget. If you do not specify a wattage, the switch delivers the maximum
value.
• Static—The switch pre-allocates power to the port even when no
powered device is connected and makes sure that power is available for
the port. The switch allocates the port-configured maximum wattage,
and the amount is never adjusted through the IEEE class or by CDP
messages from a powered Cisco end device. Because power is pre-
allocated, any powered device that uses less than or equal to the
maximum wattage is guaranteed to be powered when it is connected to
the static port. The port no longer participates in the first-come, first-
served model.
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 a powered Cisco end device needs more
than the maximum wattage, the powered device is shut down.
If you do not specify a wattage, the switch pre-allocates the maximum
value. The switch powers the port only if it discovers a powered device.
Use the static setting on a high-priority interface.
• Off—The switch disables powered-device detection and never powers
the PoE port, even if an unpowered device is connected. Use this mode
only when you want to make sure that power is never applied to a PoE
port, making the port a data-only port.