SMC Networks SMC TigerStack III SMC6824MPE - Manual (Page 186)

C
ONFIGURING THE
S
WITCH
3-136
Power Over Ethernet Configuration
This switch can provide DC power to a wide range of connected devices,
eliminating the need for an additional power source and cutting down on
the amount of cables attached to each device. Once configured to supply
power, an automatic detection process is initialized by the switch that is
authenticated by a PoE signature from the connected device. Detection
and authentication prevent damage to non-802.3af compliant devices.
The switch’s power management enables total switch power and individual
port power to be controlled within a configured power budget. Port power
can be automatically turned on and off for connected devices, and a
per-port power priority can be set so that the switch never exceeds its
allocated power budget. When a device is connected to a switch port, its
power requirements are detected by the switch before power is supplied. If
the power required by a device exceeds the power budget of the port or the
whole switch, power is not supplied.
Ports can be set to one of three power priority levels, critical, high, or low.
To control the power supply within the switch’s budget, ports set at critical
or high priority have power enabled in preference to those ports set at low
priority. For example, when a device is connected to a port set to critical
priority, the switch supplies the required power, if necessary by dropping
power to ports set for a lower priority. If power is dropped to some
low-priority ports and later the power demands on the switch fall back
within its budget, the dropped power is automatically restored.