Chapter 1: Overview
36
Power Budget The AT-8100S/24POE Switch has a power budget of 370 watts. This is
the maximum amount of power the switches can provide at one time to the
powered devices.
The PoE switch has two power supplies. Each power supply is
responsible for providing 185 watts, or half, of the power budget. Both
power supplies must be connected to AC power sources for the switch to
provide the full 370 watts. The power budget is reduced to 185 watts if
only one power supply is connected to a power source.
The power requirements of the PoE devices determine the maximum
number of devices the switch can support at one time. So long as the total
power requirements of the powered devices is less than the power budget
of the switch, the switch can supply power to all of the devices. But if the
total power requirements exceed the power budget, the switch denies
power to one or more ports using a mechanism referred to as port
prioritization.
To determine whether the power requirements of the PoE devices you
plan to connect to the switch exceed its power budget, refer to their
documentation for their power requirements and add the requirements
together. The switch should be able to power all of the devices
simultaneously as long as the total is below its power budget. If the total
exceeds the available power budget, you should consider reducing the
number of PoE devices so that all of the devices receive power.
Otherwise, the switch will power a subset of the devices, based on port
prioritization.
The switch can handle different power requirements on different ports,
enabling you to connect different classes of PoE equipment to the ports.
Table 9. IEEE Powered Device Classes
Class
Maximum Power
Output from a Switch
Port
Power Ranges of the
PDs
0 15.4W 0.44W to 12.95W
1 4.0W 0.44W to 3.84W
2 7.0W 3.84W to 6.49W
3 15.4W 6.49W to 12.95W
4 30.0W 12.95W to 25.5W