Определение
Alinkisaphysicallinefromanodetoanadjacentnodewithoutanyotherswitchingnodesinthemiddle.
Indatacommunication,thepathbetweentwocomputersisoftenformedbyaseriesofmanylinks.
Състав
Alinkiscomposedofnodesatbothendsandcommunicationlinesbetweenthenodes.
Разлика
Theconceptoflink(physicallink)isdifferentfromthatofdatalink.Inadditiontophysicallines,datalinksmustalsohaveacommunicationprotocoltocontrolthetransmissionofthesedata.Itisthedatalinkthataddsthehardwareandsoftwarethatimplementtheseprotocolstothelink.Datalinkisalsocalledlogicallink.
Класификация
Accordingtotheconnectionmethodofthecommunicationlink,thecommunicationlinkcanbedividedintothefollowingtwocategories:
Връзка за връзка от точка до точка, връзката към този момент свързва само два възела.
Multipointconnectionlinkreferstohowmany(n>2)nodesareconnectedbyonelink.
Accordingtodifferentcommunicationmethods,linkscanbedividedintothefollowingtwocategories:
Еднопосочна комуникационна връзка
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Двупосочна комуникационна връзка
Accordingtothedifferentcapacity,thelinkisdividedintothefollowingtwocategories:
Комуникационна връзка без капацитет
Комуникационна връзка с капацитет
EthernetlinkAggregation
LinkaggregationistheaggregationofmultiplephysicalEthernetportstogethertoformalogicalaggregationgroup.Theupperlayerentitythatusesthelinkaggregationservicecombinesmultiplephysicallinksinthesameaggregationgroup.Thinkofitasalogicallink.
Linkaggregationcanrealizetheloadsharingofinbound/outboundloadamongthememberportsintheaggregationgrouptoincreasebandwidth.Atthesametime,eachmemberportofthesameaggregationgroupdynamicallybacksupeachother,whichimprovesconnectionreliability.
Device AandDevice BareconnectedthroughthreephysicalEthernetlinks,andthesethreelinksarebundledtogethertobecomealogicallinkLink aggregation 1,thebandwidthofthislogicallinkItisequaltothesumofthebandwidthoftheoriginalthreeEthernetphysicallinks,thusachievingthepurposeofincreasingthelinkbandwidth;atthesametime,thesethreeEthernetphysicallinksbackupeachother,whicheffectivelyimprovesthereliabilityofthelink.