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Power classes for PDs TABLE 40
Class Usage
Power (watts) from Power-Sourcing Device
Standard PoE PoE+ High PoE Power over
HDBaseT (PoH)
0 default 15.4 15.4 15.4 15.4
1 optional 4 4 4 4
2 optional 7 7 7 7
3 optional 15.4 15.4 15.4 15.4
4 optional N/A 30
1
60
1 2
95
Power specifications
The 802.3af (PoE) standard limits power to 15.4 watts (44 to 50 volts) from the power-sourcing device,
in compliance with safety standards and existing wiring limitations. Though limited by the 802.3af
standard, 15.4 watts of power was ample for most PDs, which consumed an average of 5 to 12 watts of
power (IP phones, wireless LAN access points, and network surveillance cameras each consume an
average of 3.5 to 9 watts of power). The 802.3at 2008 (PoE+) standard nearly doubles the power,
providing 30 watts (52 to 55 volts) from the power-sourcing device. The 802.3at 2009 (High PoE)
standard increases available power again, to 60 watts for High PoE and 95 watts for Power over
HDBase-T (PoH).
NOTE
PoH ports on Brocade devices allocate 95 watts for PoE+, High PoE, and PoH PDs.
The PoE power supply provides power to the PoE circuitry block and ultimately to PoE power-
consuming devices. The number of PoE power-consuming devices that one PoE power supply can
support depends on the number of watts required by each power-consuming device and the capacity of
the power supply or power supplies. Each PoE or PoE+ port supports a maximum of 15.4 or 30 watts of
power per power-consuming device. Each PoH port supports a maximum of 95 watts of power (lower
wattage can be negotiated through LLDP messages).
As an example, if each PoE power-consuming device attached to a FastIron PoE device is budgeted to
consume 30 watts of power, one 720- or 748-watt power supply can power up to 24 PoE ports. With the
exception of the ICX6430-C12 and the ICX6450-C12-PD, FastIron platforms support either a second
power supply or an external power supply (EPS) to augment PoE power budget, depending on the
product. Refer to the power supply specifications in the Brocade FastIron hardware installation guide for
the appropriate FastIron device.
By default, a FastIron device pre-allocates power of 15.4 for a physically operational PoE configured
port, 30 watts for a PoE+ configured port, and 95 watts for a PoH port. However, in an ICX 6450-C12
device that is operational without a direct power supply and has pass-through power, there is no pre-
allocation. Instead, power is allocated only when a powered device is connected to the port. By default,
the amount of power allocated depends on the power class of the powered device.
1
First eight ports of Brocade ICX 7450-24P or ICX 7450-48P supply 95w unless PD negotiates lower power requirement through LLDP
protocol messages.
2
Maximum power required for High PoE is 60 watts.
Power over Ethernet
FastIron Ethernet Switch Administration Guide 343
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