Installation guide

Power Supply Installation Considerations
Enterasys G-Series Hardware Installation Guide 2-7
Allocation of PoE Power to Modules
TheG‐Series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IOMsandmotherboard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.
ThepoweravailableforPoEisdistributedtoeachPoE‐capablebaseboardand IOMbasedonthe
configuredallocationmode:
• Automaticmode(default),inwhichavailablepowerisdistributed
evenlytoPoE‐capable
modulesbasedonPoEportcount.Anychangeinavailablepower,duetoachangeinpower
supplystatusorredundancymodeortotheadditionorremovalofmodules,willtriggeran
automaticredistributionofpowertothePoEcontrolleroneachPoE‐capablemodule.
•
Manualmode,inwhichthepowerbudgetforeachPoE‐capablemoduleismanually
configured,usingeitherCLIcommandsortheMIBs.Thesumofthewattageconfiguredfor
eachmodulecannotexceedthetotalpoweravailableontheswitchforPoE.
Theconfiguredwattageassignmentsareusedtocalculateeach
slot’spercentageoftotal
availablepower.IfthetotalavailablePoEpowerchanges,aredistributionofavailablepower
willoccur,applyingthecalculatedpercentages.
Whenmanualdistributionmodeisconfigured,ifaPoEmoduleisaddedtotheG‐Seriesswitch,
thePoEpowerbudgetforexistingmoduleswillnotbe
recalculated.Thenewmodulewillhavea
powerbudgetofzerountilitismanuallyprovisioned.Sincethesumofthemanuallyprovisioned
wattagescannotexceedthetotalsy stempoweravailable,itmaybenecessarytoadjustexisting
budgetstofreeuppowerforthenewmodule.
WhenaPoEmodule
isremovedfromaG‐Seriesswitchconfiguredwithmanualpower
distributionmode,thePoEbudgetforeachmodulewillnotberecalculated,basedonthe
assumptionthatthemoduleremovedwillbereplacedwithanewmodulethatshouldreceivethe
sameamountofPoEpower.
Ifthepowerneeded
orrequestedexceedsthepoweravailable,thesystemwillgenerateatrapto
notifythesystemmanager.
FormoreinformationonconfiguringManualmode,seetheEnterasysG‐SeriesCLIReference.
Power Distribution Upon Power Supply Removal or Addition
Power Supply Removal
Whenapowersupplyisremoved,theG3respondstothedecreaseinavailablepowerby:
1. Detectingthepowersupplyremovalandrecalculatingavailablepower.
2. Subtractingthepowercapacityforitsbasesystemandallinstalledmodulesfromavailable
power.
3. DistributingremainingpowerequallyacrossinstalledPoEcontrollersbyreprogramming
maximumpower
ineachcontroller.
4. DroppingsupporttoPoEdevicesasnecessarytostaywithintheprogrammedmaximum
power.