Specifications

June 3, 2011 Page 1 of 14
Configuring Power over Ethernet Management
ThisdocumentprovidesinformationaboutconfiguringandmonitoringPoweroverEthernet
(PoE)
onthePoE‐compliantmodelsoftheEnterasys
®
N‐Series,S‐Series,andK‐Seriesmodular
switches,A‐Series,B‐Series,C‐Seriesstackablefixedswitches,andD‐SeriesandG‐Series
standaloneswitches.
What is PoE?
PoE,definedinIEEEstandards802.3afand802.3at, referstotheabilitytoprovide48Vdc(for
802.3af)or54Vdc(for802.3at)operationalpowerthroughanEthernetcablefromaswitchor
otherdevicethatcanprovideaPoE‐compliantportconnectiontoapowereddevice(PD).
ExamplesofPDs
arethefollowing:
•VoiceoverIPdevicessuchasPoE‐compliantdigitaltelephones
• Pan/Tilt/Zoom(PTZ)IPsurveillancecameras
• DevicesthatsupportWirelessApplicationProtocol(WAP)suchaswirelessaccesspoints
Ethernetimplementationsemploydifferentialsignalsovertwistedpaircables.Thisrequiresa
minimumoftwotwistedpairsforasinglephysicallink.
Bothendsofthecableareisolatedwith
transformersblockinganyDCorcommonmodevoltageonthesignalpair.PoEexploitsthisfact
byusingtwotwistedpairsasthetwoconductorstosupplyadirectcurrenttoaPD.Onepair
carriesthepowersupplycurrentandtheother
pairprovidesapathforthereturncurrent.
Why Would I Use PoE in My Network?
UsingPoEallowsyoutooperatePDsinlocationswithoutlocalpower(thatis,withoutAC
outlets).Havingsuchanetworksetupcanreducethecostsassociatedwithinstallingelectrical
wiringandACoutletstopowerthevariousdevices.
Notes: PoE is not supported on Enterasys
®
I-Series or X-Series devices.
For information about... Refer to page...
What is PoE? 1
Why Would I Use PoE in My Network? 1
How Do I Implement PoE? 2
Configuring PoE 4