Users Guide

Switch Feature Overview 83
Dynamic Power Management
In this mode, power is allocated based upon the detected PD class signature.
Available Power = Power Limit of the Sources – Total Allocated Power
The total allocated power is calculated as the sum of the power consumed by
each port. Dynamic mode does not reserve power for the port (the port power
limit is 0). Dynamic power management ignores LLDP-MED packets sent by
the powered device. Do not configure the powered device to send LLDPMED
packets in this mode. The powered device may draw up to the detected class
limit plus 5%.
Class-Based Power Management
Class-based power management allocates power based on the class selected by
the detected powered device signature and LLDP-MED. The detection
method must be configured as dot3at+legacy for pre-AF signature devices to
be detected.
Available Power = Power Limit of the Sources – Total Class Configured Power
The total class configured power is calculated as the sum of the class-based
power allocation for each port. Note that class-based power management
mode allocates the class limit for the port. The powered device may draw up
to the class maximum based upon the detected powered device signature.
The powered device need not draw all of the requested power. The
Consumed Power display from the show power inline command takes into
account the class reserved power. Configure the powered device to send
LLDP-MED packets in this mode. It may take up to 60 seconds to fully power
up a device in class-based management mode because LLDP-MED packets
need to be exchanged in order to configure the desired power.
Power is supplied to the device in class mode per Table 2-6.