Loading ...
Loading ...
Loading ...
8-Port and 16-Port Gigabit Ethernet Plus Click Switch
Manage Power over Ethernet User Manual63
PoE Overview
The GSS108EPP switch includes four Power over Ethernet plus (PoE+) ports. The switch
can supply up to 30W PoE+ (IEEE 802.3at) to an individual PoE+ port, with a total maximum
PoE power budget of 47W across all active PoE+ ports.
By default, supplied power is prioritized in ascending port order, up to the total power budget
of the device. If the power requirements for the attached devices exceed the total power
budget of the switch, the power to the device on the highest-numbered PoE+ port is disabled
to make sure that the devices connected to the higher-priority, lower-numbered PoE+ ports
are supported first.
It is important to note that although a device is listed as an 802.3at (PoE+) powered or
802.3af (PoE) powered device, it might not require the maximum power limit that is specified.
Many devices require less power, allowing all four PoE ports to be active simultaneously,
when the devices correctly report their PoE class to the switch.
Device Class Power Requirements
PoE and PoE+ use Ethernet cables to supply power to PoE-capable devices on the network,
such as WiFi access points, IP cameras, VoIP phones, and switches. The GSS108EPP
switch is compliant with the IEEE 802.3at standard (PoE+) and backward compatible with the
IEEE 802.3af standard (PoE). The switch can pass power through to any powered device
(PD) that supports these standards. PoE and PoE+ let you power such devices without the
need for a separate power supply.
The switch supports a Plug-and-Play process by which it detects the type of device that is
connected to one of its PoE+ ports and whether that device needs power and how much so
that the switch can provide the correct power to the device.
During the Plug-and-Play process, the connected device can provide its Class response to
the switch in many ways, depending on how the vendor programmed the device.
The following table shows the device classes for PoE+ devices adhering to the IEEE 802.3at
standard. The device classes for PoE devices adhering to the IEEE 802.3af standard are
identical with the exception that Device Class 4 is not supported.
Table 1. PoE and PoE+ device class power allocation
Device
Class
Standard Range of Power
Delivered to the
Powered Device
Minimum Output at
PoE Switch Port
(Minimum Allocated)
Maximum Output at
PoE Switch Port
(Maximum Allocated)
0 PoE and PoE+ 0.44W–12.95W 15.4W 16.2W
1 PoE and PoE+ 0.44W–3.84W 4.0W 4.2W
2 PoE and PoE+ 3.84W–6.49W 7.0W 7.4W
Loading ...
Loading ...
Loading ...