Allied Telesis AT-S105 - Manual (Page 193)

AT-S105 Management Software Web Browser User’s Guide
193
Power Budgeting The AT-FS750/24POE switch is capable of providing a maximum of
15.4 W of power per port on up to six of the twelve ports. The switch is
capable of providing a total power consumption of 100 watts, while at the
same time furnishing standard 10/100 Mbps Ethernet functionality.
The switch power management functionality supports any combination of
Ethernet ports (1-12) that supply power for a combination of IEEE 802.3af
Class 0, 1, 2, or 3 powered devices up to a maximum of 100 watts as
described in Table 8.
Note
Power is supplied to the powered devices in the order that the ports
are connected or on a first-come-first-served basis until the 100 watt
limit is reached. If the switch is power cycled after the PoE devices
are connected to the switch ports, the power is supplied to ports 1
through 12 in ascending order.
Port Power Priority
When the power budget for the switch is reached, each port is allotted
power according to its priority level. You can set the power priority of each
PoE port. There are three levels: Low, High, and Critical. By default, all of
the PoE ports are set to Low. Naturally, you want to assign a Critical level
to ports that are connected to the most important powered devices.
If you set all of the priority levels to the same value (or maintain the default
value of Low on all ports), then the port whose port number is the lowest
has the highest port power priority. For instance, if you assign PoE ports 1
through 6 with a priority level of High and the power budget is reached,
then port 1 has the highest power priority level followed by port 2, etc.
Table 8. IEEE 802.3af Class vs. Power Levels
Class Usage
Minimum Power
Levels Output at
the PSE
Maximum Power
Levels Output at
the Powered
Device
0 Default 15.4W 0.44W to 12.95W
1 Optional 4.0W 0.44W to 3.84W
2 Optional 7.0W 3.84W to 6.49W
3 Optional 15.4W 6.49W to 12.95W