Specifications

How Do I Implement PoE?
June 3, 2011 Page 2 of 14
How Do I Implement PoE?
YoucanconfigurePoEonyourPoE‐compliantEnterasysdevicethroughtheCLI‐based
procedurespresentedinthesection“ConfiguringPoE”onpage4.Aspartofyourplanto
implementPoEinyournetwork,youshouldensurethefollowing:
•ThepowerrequirementsofyourPDsarewithinthelimits
ofthePoEstandards.
•YourPoE‐compliantEnterasysdevicecansupplyenoughpowertorunyourPDs.SeeTable 1
forpowerrangesbasedoneachdeviceclass.
IfSNMPtrapsareenabled,theEnterasysdevicegeneratesatraptonotifythenetwork
administratorifanyofthefollowingoccur:
•Ifthepower
neededorrequestedexceedsthepoweravailable
•IfapowerstateoccursonaPD(forexample,whenaPDispowereduporunplugged)
IfinsufficientpowerisavailableforanattachedPD,thecorrespondingportLEDontheEnterasys
deviceturnsamber.TheLEDalsoturnsamberifa
PoEfaultoccurs(forexample,ashortinthe
Ethernetcable).
Allocation of PoE Power to Modules
TheswitchfirmwaredeterminesthepoweravailableforPoEbasedonhardwareconfiguration,
powersupplystatus,andpowersupplyredundancymode.Thesystemcalculatesandreservesthe
correctamountofpowerrequiredbytheinstalledhardwarecomponentsandthenmakesthe
balanceofpoweravailableforPoE.Whenanychangeis
madetothehardwareconfiguration,
powersupplystatus,orredundancymode,the firmwarerecalculatesthepoweravailableforPoE.
OntheS‐Series,N‐Series,andK‐Seriesswitches,youcanalsomanuallyconfigurethemaximum
percentageofPoEpoweravailabletothechassisasapercentageofthe totalinstalled
PoEpower
withthesetinlinepoweravailablecommand.(ThisfeatureisnotconfigurableontheG‐Series.)If
thepowerneededorrequestedexceedsthepoweravailable,thesystemwillgenerateatrapto
notifythesystemmanager,iftrapsareenabled.
ThepoweravailableforPoEisdistributedbased
ontheconfiguredallocationmode,setwiththe
setinlinepowermodecommand:
Table 1 PoE Powered Device Classes
Class Power Output at Port Power Range Used by Device
0 15.4 watts 0.44 to 12.95 watts
1 4.0 watts 0.44 to 3.84 watts
2 7.0 watts 3.84 to 6.49 watts
3 15.4 watts 6.49 to 12.95 watts
4 34 watts (802.3at)
Reserved (802.3af)
12.95 to 25.5 watts (802.3at)
Treat as class 0 (802.3af)
Notes: This feature is available only on the G-Series, N-Series, S-Series, and K-Series products.