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Chapter 1: Overview
Class
3
4
Power Budget
The AT-IE200-6GP and AT-IE200-6FP switches have a PoE power budget of 120 watts. This is the maximum
amount of power the switches can provide at one time to the powered devices.
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. 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 powers a subset of the devices,
based on port prioritization.
The switch can handle different power requirements on different ports. This enables you to connect different
classes of PoE equipment to the ports on the switch.
Port Prioritization
If the power requirements of the powered devices exceed the switch's power budget, the switch denies
power to some ports based on a system called port prioritization. You may use this mechanism to ensure
that powered devices critical to the operations of your network are given preferential treatment by the
switch in the distribution of power should the demands of the devices exceed the available capacity.
There are three priority levels:
Critical
High
Low
Ports set to the Critical level, the highest priority level, are guaranteed power before any of the ports
assigned to the other two priority levels. Ports assigned to the other priority levels receive power only if all
the Critical ports are receiving power. Ports that are connected to your most critical powered devices
should be assigned to this level. If there is not enough power to support all the ports set to the Critical
priority level, power is provided to the ports based on port number, in ascending order.
The High level is the second highest level. Ports set to this level receive power only if all the ports set to the
AT-IE200 Series Installation Guide
Table 3: IEEE Powered Device Classes
Maximum Power Output
from a Switch Port
15.4W
30.0W
PD Power Range
6.49W to 12.95W
12.95W to 25.5W
27
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