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首页 局域网连接设备(LAN connection device)

局域网连接设备(LAN connection device).doc

局域网连接设备(LAN connection device)

孙人俊
2018-09-16 0人阅读 举报 0 0 0 暂无简介

简介:本文档为《局域网连接设备(LAN connection device)doc》,可适用于社会民生领域

局域网连接设备(LANconnectiondevice)局域网连接设备(LANconnectiondevice)Ahub(HUB)isthesmallestunitofcentralizedmanagementofanetwork,likethetrunkofatree,whichisacollectionpointforeachbranchHUBisashareddevice,inessence,isarepeater,andthemainfunctionoftherelayistoreceivethesignalreproduction,amplification,inordertoexpandthetransmissiondistanceofthenetworkBecauseHUBisjustasignalamplifyingandtransferringdevice,itdoesnothavetheabilityofautomaticaddressing,thatis,thereisnoswitchingfunctionAlldatatransmittedtoHUBisbroadcasttotheportsthatareconnectedtoeachotherandarepronetodatacongestionTherefore,somepeoplecallhubs"sillyHUB""WhereHUBislocatedinthenetworkHUBisusedprimarilyforsharingnetworks,andisthebestandmosteconomicalsolutionforaccessingthedesktopdirectlyfromtheserverInaswitchednetwork,theHUBisdirectlyconnectedtotheswitchandsendsdatafromtheportoftheswitchtothedesktopTheuseofHUBflexiblenetworking,itisinastarnetwork,centralizedmanagementofnodesconnectedtotheworkstation,notthenormaloperationforproblemsthataffectthenetworkworkstation,andtheentryandexitofusersisfreeClassificationofHUBAccordingtothedifferentbusbandwidth,HUBisdividedintoM,MandMthreekindsofadaptiveiftheconfigurationcanbedividedintodifferentindependenttypeHUB,modularHUBandstackedHUBthreeaccordingtothemanagementmodecanbedividedintointelligentandnonintelligentHUBHUBtwoHUBcurrentlyusedisbasicallyacombinationoftheabovethreecategories,forexample,weoftentalkaboutM,adaptive,intelligent,stackableHUBandsoonHUBaccordingtothenumberofports,therearemainports,portsandportsApplicationofHUBinnetworkingBecausetheMnonintelligentHUBpricehasbeenclosetothecardprice,andMnetworkrequirementsforthetransmissionmediumandthewiringisnothigh,somanyloveDIYfriendscandoityourself,setuptheirownfamilyorofficeLANlanSetupinthepastfewyearsinthenetwork,theMnetworkalmostbecomethestandardconfigurationofthenetwork,thereareanumberofMHUBastherelayprovideslongdistancetransmissionofinformationtousersindistributedrouting,orasasmallofficenetworkcoreButthisapplicationisnolongerthemainstreamtoday,especiallywiththegrowingpopularityofMnetworks,MnetworksandtheirdeviceswillbelessandlessAlthoughthepureMHUBprovidesthetransmissionspeedofMtothedesktop,butwhenthenetworkupgradetoM,manyoftheoriginalMdevicewillnotbeabletouse,soitstartedonlyinrecentnetwork,withoutanyhesitationwillconsiderMHUBManynetworkdevicemakersareaimingatthetimingofthetransitionbetweenMandM,andhaveintroducedMcompatibleHUB,whichiscompatiblewithMTheportspeedadaptiveMHUBatworkcanbeadjustedaccordingtotheactualspeedoftheworkstationNIC:whentheworkstationcardspeedisM,whichisconnectedwiththeportspeedwillbeautomaticallyadjustedtoMwhentheworkstationcardspeedisM,thecorrespondingportspeedisautomaticallyadjustedtoMTheMadaptiveHUBisalsocalled"dualspeedHUB""Fromatechnicalpointofview,thedualspeedHUBhastwotypesofbuiltinswitchingmoduleandnoswitchingmodule,theformerisgenerallyusedasthebackboneofsmallLAN,whichisgenerallylocatedintheedgeofLVmediumnetworkapplicationsInpracticalapplication,someusersswitchtoreduceload,increasethespeedofthenetwork,connectedintheselectionandswitchHUB,alsohasadoublespeedHUBswitchmodule,sothebuiltinswitchingmoduleofdoublespeedHUBwillbethebestchoicetoupgradefromMtoMWhenselectingHUB,butalsopayattentiontotheinterfacetypesignalinputport,withRJinterfaceandtwistedpairconnectionneedsandifcabletconnected,needtohavetheBNCinterfaceisconnectedwiththethickcableneedtohaveAUIinterfacewhenlongdistanceLANconnection,butalsoneedtohavewiththeopticalfiberconnectedwiththeopticalfiberinterfaceEarlyMHUBgenerallyhasthreeinterfaces,RJ,BNC,andAUIM,HUB,andMHUBgenerallyonlyhaveRJinterfaces,Somealsohavefiberinterfaces,thecommonlyusedHUBbrandLikenetworkcards,thecurrentmarketHUBbasicallybytheUnitedStatesbrandsandTaiwanbrandoccupiedAmongthem,thehighendHUBmainlyoccupiedbyAmericanbrands,suchasCOM,INTEL,etcTaiwan'sDLINKandACCTONoccupythemainshareoflowendHUBHereisanexampleofthehub:SwitchboardSwitchworkingprincipleIoverviewIn,thelocalareanetworkswitchingequipmentappeared,andin,theupsurgeofswitchingnetworktechnologycameintobeinginchinaInfact,switchingtechnologyisakindofswitchingproductwithsimplified,lowcost,highperformanceandhighportdensityItembodiesthecomplexswitchingtechnologyofBridgeTechnologyinthesecondlayeroperationofOSIreferencemodelLikethebridge,theswitchforwardsthemessagesimplyrelativetotheMACaddressineachpacketThisforwardingdecisiongenerallydoesnottakeintoaccountthedeeperinformationhiddeninthepackageUnlikethebridge,theforwardingdelayisverysmall,andtheoperationisclosetotheperformanceofasingleLAN,farexceedingtheforwardingperformanceofthecommonbridgedinterconnectnetworkSwitchingtechnologyallowssharedanddedicatedLANsegmentstobebandwidthadjustedtomitigatebottlenecksintheflowofinformationbetweenlansNowthereareEthernet,fastEthernet,FDDIandATMtechnologyswitchingproductsSimilartotraditionalbridges,switchesprovidemanynetworkingcapabilitiesAswitchcaneconomicallydivideanetworkintosmallerconflictdomains,providinghigherbandwidthforeachworkstationThetransparencyoftheprotocolallowstheswitchinstalledinthemultiprotocolnetworkdirectlyinthesoftwareconfigurationsimplecasesswitchesuseexistingcables,repeaters,hubsandworkstationcard,doesnotneedhighlevelhardwareupgradestheswitchistransparenttotheworkstation,sothemanagementoverheadislow,simplifiestheincrease,mobileandInternetNetworknodeoperationByusingspeciallydesignedintegratedcircuits,theswitchescanforwardtheinformationinparallelatallportsonthelinespeed,providingmuchhigherperformancethanthetraditionalbridgeIntheory,asingleEthernetportcanprovideabpstransmissionrateforpacketscontainingoctalnumbersThismeansthatalinespeedEthernetswitchwithportsandparalleldatastreamsmustprovideanoverallthroughputrateofbps(channelsofinformation,Xbpschannels,informationflows)Applicationspecificintegratedcircuittechnologymakestheswitchrunatmoreports,anditsportcostislowerthanthetraditionalbridgeTwoorthreeswitchingtechnologiesportswitchingPortswitchingtechnologyfirstappearedintheslotinthehub,thehubofthebackplanearegenerallydividedintoapluralityofEthernetsegments(eachsegmentasabroadcastdomain),withoutbridgeorconnectionbetweenrouting,networkisnotcommunicatingwitheachotherAfterthemainmoduleisinserted,itisusuallyassignedtoanetworksegmentofthebackplane,whereportswitchingisusedtodistributeandbalancetheportsoftheEthernetmoduleacrossmultiplesegmentsofthebackplaneDependingonthedegreeofsupport,portswitchingcanbesubdividedinto:Moduleswitching:migratingtheentiremoduletonetworksegmentsPortgroupswitching:usuallytheportsonthemodulearedividedintogroups,eachofwhichallowsnetworkmigrationPortlevelswitching:supportforeachporttomigratebetweensegmentsThisswitchingtechnologyisbasedonthefirstlayerofOSI,andhastheadvantagesofflexibilityandloadbalancingabilityIfconfiguredproperly,itcanalsoperformacertaindegreeofcustomererror,butdoesnotchangethecharacteristicsofthesharedtransportmedium,sinceitcannotbecalledrealexchangeframeswitchingFrameswitchingisthemostwidelyusedlocalareanetworkswitchingtechnologyItprovidesaparalleltransmissionmechanismthroughdifferentialsegmentsoftraditionaltransmissionmediatoreducetheconflictdomainandobtainhighbandwidthIngeneral,eachcompany'sproductimplementationtechnologywillvary,butthenetworkframeprocessingmethodsaregenerallythefollowing:Throughswitching:providinglinespeedprocessingcapability,theswitchreadsonlythefirstbytesofthenetworkframeandtransmitsthenetworkframetothecorrespondingportStoreandforward:checkandcontrolbyreadingthenetworkframeTheexchangerateoftheformermethodisveryfast,butthelackofmoreadvancedcontrolofnetworkframes,lackofintelligenceandsecurity,andtheexchangeofportswithdifferentspeedsarealsonotpossibleAsaresult,manufacturersfocusonthelattertechnologySomemanufacturersevenonthenetworkframedecomposition,theframeisdecomposedintofixedsizecells,thecellprocessingeasilyinhardware,fastprocessingspeed,andcanaccomplishtheadvancedcontrolfunctions(suchastheUnitedStatesMADGEcompanyLEThub)suchasprioritycontrolcellswitchingATMtechnologyrepresentsthefuturedirectionofnetworkandcommunicationtechnologydevelopment,andisalsoa"goodmedicine"tosolvemanyproblemsinnetworkcommunicationATMusesbytesofcellexchangewithfixedlengthBecauseofitsfixedlength,itiseasytoimplementwithhardwareATMusesdedicatednondifferentialconnectionstoruninparallel,allowingmultiplenodestobeestablishedsimultaneouslythroughaswitchwithoutaffectingthecommunicationcapabilitiesofeachnodeATMalsoallowsmultiplevirtuallinkstobebuiltbetweensourcenodesandtargetnodestoensureadequatebandwidthandfaulttoleranceATMusesstatisticaltimedivisioncircuittoreuse,soitcangreatlyimprovetheutilizationofthechannelThebandwidthofATMcanreachM,M,MandevenGbtransmissioncapabilityThree、typesandselectionofLANswitchesLANswitchescanbedividedaccordingtothenetworktechnologyused:LargenetworkswitchTokenringswitchFDDIswitchesATMswitchesFastEthernetswitches,etcIfdividedbytheswitchapplicationfield,canbedividedinto:DesktopswitchWorkgroupswitchesBackboneswitchEnterpriseswitchesSubsectionswitchPortswitchNetworkswitches,etcLocalareanetworkswitchisthecoreequipmentofthenetworksystemForusers,themainindicatorsofLANswitchesareportconfiguration,dataexchangecapability,packetswitchingspeedandotherfactorsTherefore,whenchoosingswitches,payattentiontothefollowing:()thenumberofswitchingports()thetypeofexchangeport()theabilityofexpansionofthesystem()trunkconnectionmeans()totalswitchingcapacityoftheswitch()whetherroutingcapabilityisrequired()whetherthermalswitchingcapabilityisrequired()doesitrequirefaulttolerance()whetheritcanbecompatiblewithexistingequipmentandsmoothlylinkup()networkmanagementabilityFour,severalnoteworthyproblemsintheapplicationofswitchesBottleneckprobleminswitchnetworkTheprocessingspeedoftheswitchitselfcanreachveryhigh,anduserstendtobesuperstitiousabouttheGbpshighspeedbackplanethatisadvertisedbythemanufacturerInfact,thisisamisconceptionthatthenetworkorserverthatconnectstothenetworkusesalargenetwork,whichfollowstheCSMACDmediumaccessruleInthecurrentclientservernetwork,multipleworkstationswillaccesstheserveratthesametime,soitisveryeasytoformaserverbottleneckSomemanufacturershavetoconsiderthispoint,intheswitchdesignoneormorehighspeedports(suchasCOMLinkswitchcanbeconfiguredwithoneortwoMbpsports),convenientforuserstoconnecttotheserverorahighspeedbackbonenetworkUserscanalsoeliminatebottlenecksbydesigningmultipleservers(forBusinessDivision)orbyaddingmultiplenetworkcardsSwitchescanalsosupportspanningtreealgorithmstofacilitateuserarchitectureforfaulttolerantredundantconnectionsbroadcastframesinanetworkAtpresent,thewidelyusednetworkoperatingsystemsareNetware,Windows,NTandsoon,whileLanServerserversprovideservicestoclientsbysendingnetworkbroadcastframesThepresenceofbroadcastpacketsinsuchLANswillgreatlyreducetheefficiencyoftheswitches,whichcanbelimitedtoacertainextentbyusingthevirtualnetworkfunctionalityoftheswitch(noteveryswitchsupportsvirtualnetworks)EachoftheswitchportssupportacertainnumberofMACaddress,thisswitchcan"memory"oftheportgroupisconnectedwiththesite,locationvendorsprovidedifferentswitchportssupportMACnumberisnotthesame,theusermustpayattentiontotheconnectionendpointswitchportIfthenumberofMACmanufacturersmorethanagiven,switchreceivesanetworkframe,onlythedestinationMACaddressdoesnotexistintheswitchportMACaddresstable,thentheframewillbetobroadcasttoeachportoftheswitch,thedivisionofvirtualnetworksThevirtualnetworkisanimportantfunctionoftheswitch,andusuallytherearethreeformsofthevirtualnetwork:()staticportallocationThedivisionofastaticvirtualnetworkisusuallyanetworkadministratorwhousesnetworkmanagementsoftwareordirectlysetstheportoftheswitchtodirectittoavirtualnetworkTheseportsalwaysmaintainthesepropertiesunlessthenetworkadministratorresetsthemAlthoughthismethodistroublesome,itisrelativelysafe,easytoconfigureandmaintain()dynamicvirtualnetworkPortssupportingdynamicvirtualnetworkscanautomaticallydeterminetheirdependencybymeansofintelligentmanagementsoftwareTheportdeterminesthedependencyofthevirtualnetworkbymeansoftheMACaddress,logicaladdress,orprotocoltypeofthepacketWhenanetworknodeisjustconnectedtothenetwork,theswitchportisnotallocated,sotheswitchdynamicallydividestheportintoavirtualnetworkbyreadingtheMACaddressofthenetworknodeOncetheadministratorisconfigured,theuser'scomputercanflexiblychangetheswitchport,withoutchangingtheuser'svirtualnetworkfromtheproperty,butifthereisnotdefinedtheMACaddressofthenetwork,itcangiveanalarmtotheadministrator()multivirtualnetworkportconfigurationTheconfigurationsupportsoneuseroroneporttoaccessmultiplevirtualnetworkssimultaneouslyThiscanbeanetworkservertomultiplebusinessunits(eachbusinesssetintoavirtualnetwork)canvisitatthesametime,youcanalsoaccessapluralityofvirtualnetworkresourcesatthesametime,alsocanmakemultipleconnectionsbetweenthevirtualnetworkonlyoneportcanbecompletedButitcancausesecurityproblemsTheindustrystandardsforvirtualnetworksarebeingdeveloped,sotheproductsofeachcompanyarenotinteroperableCiscohasdevelopedtheInterSwitchLink(ISL)virtualnetworkprotocol,whichsupportscrosscorenetworks(ATM,FDDI,Fast,Ethernet)virtualnetworksButthedealhasbeencriticizedforlackofsecurityconcernsIntraditionalcomputernetworks,alargenumberofsharedHubareused,andgoodresultscanbeachievedbyflexibleaccesstocomputerportsapplicationofhighspeedLANtechnologyAlthoughFastEthernettechnologymaintainsgoodcompatibilitywithtraditionalnetworkinsomeways,BASETX,BASAETandBASEFXhavegreatrestrictionsontransmissiondistanceandconnectionTheselimitationscanbebrokenthroughMbpsswitchesAtthesametime,onlyswitchportscansupportduplexhighspeedtransmissionAtpresenttherehavebeenCDDIFDDIswitchingtechnology,inadditiontotheCDDIFDDIportpricesalsoshowedadownwardtrend,butalsohasacomparativeadvantageinthetransmissiondistanceandsafety,soitisagoodchoiceforlargebackbonenetworkInadditiontothedesignneedstoconsiderthespecificneedsofthenetworkenvironment(emphasisonportcollocationreasonable),butalsoneedtoconsiderfromtheoverall,suchasnetworkmanagement,networkapplicationsWiththedevelopmentandmaturityofATMtechnologyandtheintensificationofmarketcompetition,thepriceofframeswitcheswillgodownfurther,anditwillbecomeanimportantsolutiontotheworknetworkingThefollowingfigureshowsthebackboneswitchofGigabitEthernetontopofwhichisanordinaryswitchRouterArouterisanetworkdevice,(shownbelowisaCOMrouter)thatenablesyoutoconnectlocalorremoteindependentnetworksusingoneormorenetworkprotocols,eachwithitsownlogicalidentityRoutersuselogicalidentifierstoroutepacketsofaspecifiedtype,suchasIP,fromonenodeinalogicalnetwork,toanothernodeonanothernetwork"Seehere"

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