Enterasys SecureStack A2 A2H124-24P - Stack Connections; Redundant Power Supply Capability; Poe (Power over Ethernet) Support

PoE (Power over Ethernet) Support
1-4 Introduction
Stack Connections
Theswitcheshavefront‐panelRJ45connectorsforconnectionsinastackconfiguration.
ThestackingcablesusedfortheconnectionsarestandardCategory5orbetterUTPcable.
Redundant Power Supply Capability
TheSecureStackA2haspowersupplyredundancycapabilitywhenconnectedtoan
optionalexternalredundantpowersupply(RPS).Iftheinternalpowersupplyfails,the
RPSassumestheentireloadoftheSecureStackA2withoutinterruptingnetworktraffic.
TheinternalpowersupplyandRPSeachhavetheirownACpowerconnection,
which
enablestheconnectionofeachpowersupplytoadifferentACpowercircuitfor
additionalACpowersourceredundancy.
PoE (Power over Ethernet) Support
Theswitchis802.3afcompliant,whichmeansitcanprovidepoweroverEthernetcable
connectionsfromitsRJ45frontpanelconnectorstoPDs(powereddevices)inthenetwork.
PoweroverEthernet(PoE)referstotheabilitytoprovide48Vdcpowertoapowered
deviceusingthesame Ethernetcablingtha t
providesdata.Modern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.Onepaircarriesthepowersupplycurrentandtheotherpairprovidesapathfor
thereturncurrent.WhileseveralproprietarylegacyimplementationsofPoEhavebeen
deployedbyLANequipmentvendors,in2003theIEEEpublishedthe
IEEE802.3af‐2003
specification,whichispartofthe802.3suiteofstandards.
TheswitchisfullycompliantwiththeIEEE802.3afstandard.Itsupports thestandard
resistor‐baseddetectionmethod,aswellasACdisconnectcapability.Theswitchcan
provideupto360wattsofPoEpowerandiscapable
ofsupplyingamaximumof15.4
wattstoany10/100port.Inadditionitiscapableofproviding7.5wattsofpowertoall
portssimultaneously.
EachPDhasaPDC(PoweredDeviceClassification)thatistransmittedtotheswitchfor
powermanagementpurposes.Table1‐1liststheclassificationsand
theassociatedpower
ranges.