Chapter 1: Overview
PoE Powered Device Classes
PoE Power
Budget
Powered devices are grouped into the five classes listed in Table 6. The classes are based on the amount of power the devices require. The switches support all five classes.
Table 6. IEEE Powered Device Classes
| Maximum Power |
|
Class | Output from a Switch | PD Power Range |
| Port |
|
|
|
|
|
|
|
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 |
|
|
|
The
The sum of the power requirements of each of the PoE devices connected to the switch determines the maximum number of devices that 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 the documentation for the power requirement of each device 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 PoE ports on the switch.
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