ZyXEL Communications ES-2024PWR Manual

POE
Ethernet Switch
ZyNOS 4.00
Support Notes
Version 4.00 October 2011

PoE Support Note
All contents copyright (c) 2011 ZyXEL Communications Corporation.
2
Overview of Power over Ethernet
Power over Ethernet or PoE technology describes a system to pass electrical power safely, along
with data, on Ethernet cabling. The IEEE standard for PoE requires category 5 cable or higher for high
power levels, but can operate with category 3 cable for low power levels. Power is supplied in common
mode over two or more of the differential pairs of wires found in the Ethernet cables and comes from a
power supply within a PoE-enabled networking device such as an Ethernet switch or can
be injected into a cable run with a midspan power supply.
The original IEEE 802.3af-2003 PoE standard provides up to 15.4 W of DC power (minimum 44 V
DC and 350 mA) to each device. Only 12.95 W is assured to be available at the powered device as
some power is dissipated in the cable.
The updated IEEE 802.3at-2009 PoE standard also known as PoE+ or PoE plus, provides up to 25.5
W of power. The 2009 standard prohibits a powered device from using all four pairs for power. Some
vendors have announced products that claim to be compatible with the 802.3at standard and offer up
to 51 W of power over a single cable by utilizing all four pairs in the Cat.5 cable.
The following table shows the IEEE 802.3af power classification of the Powered Devices.
This is a number from 0 to 4, where each value represents a range of power (W) that the PD
requires to function. The ranges are as follows.
Class 0 - Default, 0.44 to 12.94 W
Class 1 - Optional, 0.44 to 3.84 W
Class 2 - Optional, 3.84 to 6.49 W
Class 3 - Optional, 6.49 to 12.95 W
Class 4 - Reserved (PSEs classify as Class 0)
Benefits
•Lower Cost –External “wall wart”power supplies can be eliminated.
•Flexible access point location –Wireless access points no longer need to be located near
AC power source or need power lines and outlets.
•Remote management –IP phone, WLAN access points can be powered up or down
remotely.

PoE Support Note
All contents copyright (c) 2011 ZyXEL Communications Corporation.
3
EndSpan & MidSpan
There are two kinds of PoE solutions in the world, Endspan and Midspan. Usually a PoE
switch would be an endspan solution, while a PoE Injector would be a midspan solution. (ex.
PoE-12, PoE-80)
Alternative A is also called “Endspan”, which means that data and power are in the same
twisted pairs. Power is carried over the data pairs (1/2 & 3/6)
Alternative B is also called “MidSpan” which means that data and power are NOT in the
same twisted pairs. Power is carried over the spare pairs (4/5 & 7/8)

PoE Support Note
All contents copyright (c) 2011 ZyXEL Communications Corporation.
4
Our PoE
Our products (switch & injector) which support IEEE 802.3af-2003: ES-2024PWR,
ES-2108PWR, ES-3124PWR, GS1500-24P, GS2200-24P, PoE-10, PoE-12, PoE-80.
Our products (switch & injector) which support IEEE 802.3at-2009:
GS2200-8HP (only port 1~4 have HP), PoE12-HP.
Scenario
We connect PoE-enabled devices to our switch (GS2200-8HP), and then we proceed
to set up PoE on the switch.

PoE Support Note
All contents copyright (c) 2011 ZyXEL Communications Corporation.
5
How to configure PoE (GS-2200-8HP)
1. Click Basic Setting > PoE Setup in the navigation panel to display the
screen as shown below. Use this screen to configure PoE settings.
2. You can choose the PoE mode (GS2200-8HP only has consumption mode)
and enable PD & PD priority.

PoE Support Note
All contents copyright (c) 2011 ZyXEL Communications Corporation.
6
3. After configuring PoE settings we need to use CLI to enable PoE on the
port-interface.

PoE Support Note
All contents copyright (c) 2011 ZyXEL Communications Corporation.
7
Configuration using the CLI
Command Examples
1. Enable PoE on port interface and set usage threshold and MIB traps.
sysname# configure
sysname(config)# pwr interface 1-4
sysname(config)# pwr usagethreshold 25
sysname(config)# pwr mibtrap
sysname(config)# exit
2. Check the PoE status in CLI
GS2200# sh pwr