Specifications

clear ciscodp Link Layer Discovery Protocol and LLDP-MED
Enterasys Matrix N Standalone (NSA) Series Configuration Guide 3-15
Link Layer Discovery Protocol and LLDP-MED
TheIEEE802.1ABstandard,commonlyreferredtoastheLinkLayerDiscoveryProtocol(LLDP),
isdescribedin“IEEE802.1AB‐2005Edition,IEEEStandardforLocalandMetropolitanNetworks:
StationandMediaAccessControlConnectivityDiscovery,May2005.”
LLDP‐MEDisdescribedintheANSITIAStandardsdocument“TIA‐1057‐2006,Link
Layer
DiscoveryProtocolforMediaEndpointDevices.”
LLDPissimilartotheEnterasysDiscoveryProtocolandtheCiscoDiscoveryProtocolinthatit
providesanindustrystandard,vendor‐neutralwaytoallownetworkdevicestoadvertisetheir
identitiesandcapabilitiesonalocalareanetwork,andtodiscoverthatinforma tionabout
their
neighbors.
LLDPoperatesonphysicalports.LLDPisnotsupportedonLAGports.
LLDP‐MEDisanenhancementtoLLDPthatprovidesthefollowingbenefits:
•Auto‐discoveryofLANpolicies,suchasVLANid,802.1ppriority,andDiffServcodepoint
settings,leadingto“plug‐and‐play”networking
•Devicelocationandtopologydiscovery,
allowingcreationoflocationdatabasesand,inthe
caseofVoIP ,provisionofE911services
•Extendedanda utoma tedpowermanagementofPoweroverEthernetendpoints
•Inventorymanagement,allowingnetworkadministratorstotracktheirnetworkdevicesand
todeterminetheircharacteristics,suchasmanufacturer,softwareandhardwareversions,and
serialorassetnumbers
TheinformationsentbyanLLDP‐enableddeviceisextractedandtabulatedbyitspeers.The
communicationcanbedonewheninformationchangesoronaperiodicbasis.Theinformation
tabulatedisagedtoensurethatitiskeptuptodate.Portscanbeconfiguredtosendthis
information,receive
thisinformation,orbothsendandreceive.
EitherLLDPorLLDP‐MED,butnotboth,canbeusedonaninterfacebetweentwodevices.A
switchportusesLLDP‐MEDwhenitdetectsthatanLLDP‐MED‐capabledeviceisconnectedtoit.
LLDP Frames
LLDPinformationiscontainedwithinaLinkLayerDiscoveryProtocolDataUnit(LLDPDU)sent
inasingle8 02.3Ethernetframe.TheinformationfieldsinLLDPDUareasequenceofshort,
variable‐length,informationelementsknownasTLVs—type,length,andvaluefieldswhere:
•Typeidentifieswhatkindofinformationis
beingsent
•Lengthindicates thelengthoftheinformation stringinoctets
•Valueistheactualinformationthatneedstobesent
ThestandardspecifiesthatcertainTLVsaremandatoryintransmittedLLDPDUs,whileothersare
optional.Youcanconfigureonaport‐specificbasiswhichoptionalLLDPandLLDP‐MEDTLVs
shouldbesentinLLDPDUs.
Configuration Tasks
Thecommandsincludedinthisimplementationallowyoutoperformthefollowingconfiguration
tasks: