Composition – H3C Technologies H3C S7500E Series Switches User Manual
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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
, a PoE system consists of 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 is a device supplying power for PDs. A PSE can be built-in (Endpoint) or
external (Midspan). A built-in PSE is integrated in a switch, and an external PSE is
independent from a switch or router. The PSEs of H3C are built in, and can be classified
into two types:
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Device with a single PSE: Only one PSE is available on the device; so the whole device is
considered as a PSE.
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Device with multiple PSEs: For a device with multiple PSEs, an interface board with the
PoE power supply capability is a PSE. The system uses PSE IDs to identify different PSEs.
You can use the display poe device command to display the mapping between a PSE ID
and the slot number of an interface board.
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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.
For an S7500E series Ethernet switch, the formula for calculating PSE IDs is as follows:
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For a distributed device: The slot number of LPU x 3 + 1. For example, if the slot number is
3, the PSE ID is 3 x 3 + 1.
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For a distributed IRF device: The slot number of ((Chassis-1) x 14 + LPU) x 3 + 1. For
example, if the chassis is 3 slot number is 4, the PSE ID is ((3-1) x 14 + 4) x 3 + 1.
3) PI: An Ethernet interface with the PoE capability is called PoE interface. Currently, a PoE
interface can be an FE or GE interface.
4) PD: A PD is a device accepting power from the PSE, including IP phones, wireless APs,
chargers of portable devices, POS, and web cameras. The PD that is being powered by the
PSE can be connected to another power supply unit for redundancy power backup.