Configuration Guide User guide

672 FastIron Configuration Guide
53-1002494-02
Setting the power class for a PoE power- consuming device
Setting the power class for a PoE power-
consuming device
A power class specifies the maximum amount of power that a Brocade PoE or PoE+ device will
supply to a power consuming device. Table 124 shows the different power classes and their
respective maximum power allocations.
Setting the power class configuration notes
Consider the following points when setting the power class for a PoE power-consuming device.
• The power class sets the maximum power level for a power consuming device. Alternatively,
you can set the maximum power level as instructed in the section “Setting the maximum power
level for a PoE power- consuming device” on page 670. For each PoE port, you can configure
either a power class or a maximum power level. You cannot configure both. You can, however,
configure a power level on one port and a power class on another port.
• The power class includes any power loss through the cables. For example, a PoE port with a
power class of 3 (15.4 watts) will receive a maximum of 12.95 watts of power after 2.45 watts
of power loss through the cable. This is compliant with the IEEE 802.3af and 802.3at
specifications for delivering inline power. Devices that are configured to receive less PoE
power, for example, class 1 devices (4.0 watts), will experience a lower rate of power loss
through the cable.
• The Brocade PoE or PoE+ device will adjust the power on a port only if there are available
power resources. If power resources are not available, the following message will display on
the console and in the Syslog:
PoE: Failed power allocation of 30000 mwatts on port 1/1/21. Will retry when
more power budget.
Setting the power class command syntax
To configure the power class for a PoE power consuming device, enter commands such as the
following.
Brocade# configure terminal
Brocade(config)# interface ethernet 1/1
Brocade(config-if-e1000-1/1)# inline power power-by-class 2
TABLE 124 Power classes for PDs
Class Usage Power (watts) from Power Sourcing Device
Standard PoE PoE+
0default15.430
1optional4 4
2optional7 7
3 optional 15.4 15.4
4optional15.430