Users Guide

Table Of Contents
84 Switch Feature Overview
Table 2-6. Class-based Power Management
In four-pair mode, for classes 0-4, twice the power listed in Table 2-6 above is
delivered. Classes 5 and 6 may be two, three, or four-pair power. For
information about the available system power, see the Hardware Overview
chapter.
Power Management in Guard Band
All Dell EMC Networking PoE-capable switches support a dynamic guard
band, which means that the guard band used varies depending upon the
following factors:
Power management mode
Class of the device being powered up.
Prior to a device being powered up, the switch calculates the following:
threshold power
guard band
(current power consumption + computed
power draw of the new device)
If this value is less than zero (which means powering up the new PD device
will put the total power draw into the guard band or above the switch power
capacity), then the switch does not power up the new device. A device being
powered up in class or dynamic mode is always supplied with 15.4 watts at
startup. Once the device class or power draw is determined, power to the
device may be reduced or increased.
Class Usage AF/AT Device (Watts) BT Device (Watts) PD Type
0 Default 15.4 4 1 802.3af
1 Optional 4 4 1 802.3af
2 Optional 7 7 1 802.3af
3 Optional 15.4 15.4 1 802.3af
4 802.3at
or
802.3bt
30 30 2 802.3at
5 802.3bt NA 45 3 802.3bt
6 802.3bt NA 60 3 802.3bt