Chapter 13
| Basic Administration Protocols
Power over Ethernet
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Ports can be set to one of three power priority levels, critical, high, or low. To control
the power supply within the switch’s budget, ports set at critical to high priority
have power enabled in preference to those ports set at low priority. For example,
when a device connected to a port is set to critical priority, the switch supplies the
required power, if necessary by denying power to ports set for a lower priority
during bootup.
Note:
For more information on using the PoE provided by this switch refer to the
Installation Guide.
Setting the Port
PoE Power Budget
Use the Administration > PoE > PSE page to set the maximum power provided to a
port.
Command Usage
â—† This switch supports both the IEEE 802.3af PoE and IEEE 802.3at-2009 PoE Plus
standards. To ensure that the correct power is supplied to powered devices
(PD) compliant with these standards, the first detection pulse from the switch is
based on 802.3af to which the 802.3af PDs will respond normally. It then sends
a second PoE Plus pulse that causes an 802.3at PD to respond as a Class 4
device and draw Class 4 current. Afterwards, the switch exchanges information
with the PD such as duty-cycle, peak and average power needs.
â—† All the RJ-45 ports support both the IEEE 802.3af and IEEE 802.3at standards.
â–
For the ECS4620-28P, the total PoE power delivered by all ports cannot
exceed the maximum power budget of 410W. This means that up to 13
ports can supply a maximum 30W of power simultaneously to connected
devices (802.3at), or up to 24 ports can supply up to 15.4W (802.3af).
â–
For the ECS4620-52P, the total PoE power delivered by all ports cannot
exceed the maximum power budget of 730W when power is provided from
the RPS. This means that up to 23 ports can supply a maximum 30W of
power simultaneously to connected devices (802.3at), or up to 48 ports can
supply up to 15.4W (802.3af).
â—† If a device is connected to a switch port and the switch detects that it requires
more than the power budget set for the port or to the overall switch, no power
is supplied to the device (i.e., port power remains off).
â—† If the power demand from devices connected to all switch ports exceeds the
power budget set for the switch, the port power priority settings are used to
control the supplied power. For example:
â–
If a device is connected to a low-priority port and causes the switch to
exceed its budget, power to this port is not turned on.
â–
If a device is connected to a critical or high-priority port and would cause
the switch to exceed its power budget as determined during bootup,
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