PoE configuration (available only on the A3100
v2 EI)
PoE overview
Introduction to PoE
Power over Ethernet (PoE) enables a power sourcing equipment (PSE) to supply power to powered
devices (PDs) from Ethernet interfaces through twisted pair cables.
Advantages
• Reliable—Power is supplied in a centralized way so that it is convenient to provide a backup power
supply.
• Easy to connect—A network terminal requires no external power supply but only an Ethernet cable.
• Standard—It is in compliance with IEEE 802.3af, and adopts a globally uniform power interface.
• Promising—It can be applied to IP telephones, wireless LAN access points (APs), portable chargers,
card readers, web cameras, and data collectors.
Composition
As shown in Figure 29, a PoE system comprises PoE power, PSE, power interface (PI), and PD.
1. PoE power—The whole PoE system is powered by the PoE power.
2. PSE—A PSE supplies power for PDs. A PSE can be built-in (Endpoint) or external (Midspan). A
built-in PSE is integrated in a switch or router, and an external PSE is independent from a switch or
router. HP PSEs are built in and can be classified into two types:
• Device with a single PSE—Only one PSE is available on the device, so the whole device is
considered a PSE.
• Device with multiple PSEs—For a device with multiple PSEs, an interface card with the PoE power
supply capability is a PSE. The system uses PSE IDs to identify different PSEs. To display the mapping
between a PSE ID and the slot number of an interface card, execute the display poe device
command.
A PSE can examine the Ethernet cables connected to PoE interfaces, search for PDs, classify them, and
supply power to them. When detecting that a PD is unplugged, the PSE stops supplying power to the PD.
3. PI—An Ethernet interface with the PoE capability is a PoE interface. A PoE interface can be an FE
or GE interface.
4. PD—A PD accepts power from the PSE, including IP phones, wireless APs, chargers of portable
devices, POS, and web cameras.
5. The PD that is being powered by the PSE can be connected to another power supply unit for
redundancy power backup.
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