Независими посетители
UV (Независим посетител): а именно Уникален посетител, компютърен клиент, който посещава уебсайта, е посетител. Същият клиент в рамките на 00:00-24:00 се брои само веднъж. acampusмрежа според мрежовия трафик.
The"80/20"rule
Intraditionalnetworks,userswhousethesameapplicationaregenerallyplacedinthesameworkgroup,andtheserverstheyfrequentlyusearealsoplacedtogether.TheworkinggroupislocatedinthesamephysicalnetworksegmentorVLAN(virtuallocalareanetwork).Thepurposeofthisistolimitthedatatrafficgeneratedbetweentheclientandtheserveronthenetworkwithinthesamenetworksegment.Inthesamenetworksegment,youcanusearelativelyhigh-bandwidthswitchtoconnecttheclientandserver,insteadofusingarelativelylow-bandwidthrouter.Thisnetworkdesignmodethatcontrolsmostofthenetworktrafficlocallyiscalledthe"80/20rule",thatis,80%ofthenetworktrafficislocaltraffic(usingswitchestoexchangedata)andistransmittedinthesamenetworksegment;only20%Ofthenetworktrafficneedstopassthroughthenetworkbackbone(routerorLayer3switch).
The"80"and"20"inthe"80/20"rulecannotbesimplyunderstoodasnumbers,butshouldbeunderstoodasthewaynetworktrafficisdistributed,thatis,mostnetworktrafficisconfinedtothelocalworkinggroup.Partofthetrafficpassesthroughthenetworkbackbone.Therefore,inactualnetworkdesign,aslongasmostofthenetworktrafficislocalandasmallpartofthenetworktrafficpassesthroughthebackbone,itisconsideredtocomplywiththe"80/20"rule,regardlessoftheactualnumberratio.
Application
Inthecampusnetwork,thesoftware-onlymultimediaelectronicclassroomisasmallnetworkthatconformstothe"80/20"rule.Multimedianetworkclassroomsaremainlyusedinthesameclassroomorteachingbuilding.Multicastandbroadcastmethodsareoftenusedtosendmultimediadatafromtheteachercomputertothestudentcomputer,soalotofdatastreamsaregenerated.Ifnotprocessed,thedatastreamwillforma"broadcaststorm"andspreadtootherpartsofthenetwork.Therefore,thenetworksegmentwherethemultimedianetworkclassroomislocatedneedstobedividedintoanindependentsubnettosuppressthebroadcaststorm.
Правилото „20/80“
С постепенното обогатяване на мрежовите приложения, правилото „80/20“ вече не може напълно да отговаря на нуждите от мрежов дизайн. Постепенно се популяризира модел, наречен „централизирано съхранение, разпределено изчисление“. b услуги, системи за електронна поща и все по-популярния VOD (видео по заявка), библиотека с мултимедийни ресурси, образователен център за данни (EDC), цифрова библиотека и т.н.; изчисляване на разпространението означава, че данните се изтеглят на всяка работна станция за обработка, като например използване на библиотеката с мултимедийни ресурси в мрежата за създаване на софтуер за мултимедийни курсове, сърфиране в цифровата библиотека и т.н. силно се отклониха от правилото "80/20" и се появи ново правило, което е правилото "20/80".
Inanetworkthatcomplieswiththe"20/80"rule,onlyabout20%ofthenetworktrafficisconfinedtothelocalworkinggroup,andabout80%ofthenetworktrafficistransmittedthroughthenetworkbackbone.Thischangeofnetworktrafficmodehasbroughtagreatloadtothebackboneswitchofthecampusnetwork.Therefore,inanidealstate,thebackboneswitchshouldbeabletoprovideperformancethatmatchesthatofthebackboneswitchesconnectedbelow,thatis,providewire-speedthree-layerswitching,thatistosay,howfastthebackboneswitchbelowcanrun,thebackboneswitchaboveshouldalsobeabletoHowfasttorun.Similarly,iftherearemanyVLANsdividedbyfunction(suchasteaching,scientificresearch,andadministrativemanagement)inthenetwork,theseVLANsarealsodifficulttomanage.Intheprevious"80/20"rule,serverswereoftendistributedinVLANs,soaccesswasfasterforeachworkgroup.However,inthe"20/80"rule,serversareoftenconcentratedinthecenterofthenetwork,soforeachworkinggroup,cross-VLANaccessmustbeimplemented.
Classificationconcept
Manynetworkapplicationshavetheirowncharacteristicsandhavedifferentrequirementsforthenetworkenvironment.Therefore,onlytimelyandaccurateidentificationandclassificationofnetworktrafficcanbeaccuratelyProvideasuitablenetworkenvironmentfordifferentapplications,effectivelyusenetworkresources,andprovideuserswithbetterservicequality.Theresearchonnetworktrafficclassificationisveryextensive,andtherearemanymethodsused,buttheyaremainlybasedonthefollowingthreelevels:(1)Packet-leveltrafficclassification:mainlyfocusesonthecharacteristicsofpacketsAnditsarrivalprocess,suchasthedistributionofdatapacketsize,thedistributionofdatapacketarrivaltimeinterval,etc.;
(2)Класификация на потока на ниво поток: Фокусирайте се главно върху характеристиките на потока и процеса на неговото пристигане, може да бъде TCP връзка или UDP поток. Сред тях потокът обикновено се отнася до пет кортежа, съставени от IP адрес на източника, порт на източника, IP адрес на местоназначение, порт на местоназначение и протокол на приложение;
(3)Stream-leveltrafficclassification:mainlyfocusesonhostpairsAndtheapplicationtrafficbetweenthem,usuallyreferstoatripletcomposedofsourceIPaddress,destinationIPaddress,andapplicationprotocol,whichissuitableforstudyingthelong-termtrafficstatisticscharacteristicsofthebackbonenetworkonamorecoarse-grainedbasis.
Intheabovethreelevelsoftrafficclassification,themostwidelyusedisFlow-leveltrafficclassification.Thismethodofanalyzingdatatransmittedinthenetworkbystreamisaninevitablerequirementforthedevelopmentofpacketswitchingnetworks.
EvaluationIndex
Akeymetricfortrafficclassificationistheaccuracyofacertainclassificationtechnologyorclassificationmodeltoclassifyunknowndataobjects.Theevaluationcriteriausuallyusedtomeasuretheaccuracyofclassificationmainlyincludethefollowingfouraspects:
True(truepositive,TP):indicatesthenumberofpositivesamplescorrectlypredictedbytheclassificationmodel,thatis,theybelongtocategoryAandareThenumberofsamplespredictedtobecategoryA.
Falsenegative(FN):indicatesthenumberofpositivesamplesthatareincorrectlypredictedbytheclassificationmodelasnegative,thatis,thenumberofsamplesthatbelongtocategoryAbutarepredictedtonotbelongtocategoryA.
Falsepositive(FP):indicatesthenumberofnegativesamplesthatareincorrectlypredictedbytheclassificationmodelaspositive,thatis,thenumberofsamplesthatdonotbelongtocategoryAbutarepredictedtobelongtocategoryA.
Truenegative(TN):indicatesthenumberofnegativesamplescorrectlypredictedbytheclassificationmodel,thatis,thenumberofsamplesthatdonotbelongtocategoryAandarepredictedtonotbelongtocategoryA.
Inaddition,classificationmethodsbasedonmachinelearningusuallyusetwoothermetricstoevaluatetheirclassificationresults,whicharedefinedasfollows:recall:recall=TP/(TP+FN),whichmeansTheproportionofsamplesincategoryAthatarecorrectlypredicted.
Precision(precision):precision=TP/(TP+FP),whichmeansthatamongallthesamplespredictedtobeclassA,theproportionofsamplesthatreallybelongtoclassA.Manytrafficclassificationstudiesuseflowaccuracyorbyteaccuracyasametricfortheirexperimentalresults.Flowaccuracyrepresentstheproportionofcorrectlyclassifiedflows,whilebyteaccuracypaysmoreattentiontothecorrectclassificationofflows.Thenumberofbytescarried.Amongthem,thedefinitionofaccuracyisasfollows:
Точност:точност=(TP+TN)/(TP+TN+FP+FN),което означава,чеброят на пробите е правилно предвиден от класификационния модел в общия процент впробата.
Switch
Withoutathree-layerswitch,VLANscannotcommunicate.VLANsaresimilartothelogicalpartitionsofharddisksandcanbesimplyunderstoodasdividingthesameharddiskintodifferentharddiskdriveletters.Butunlikelogicaldisks,communicationbetweenVLANsisnotassimpleascopyingfilesfromonelogicaldisktoanotherlogicaldisk.Instead,routersmustrelyonthemtocommunicatebetweenVLANs.
Функция
1.Гръбнакът на мрежата е незаменим за трислойния превключвател
Tosaythattheroleofthethree-layerswitchinmanynetworkequipment,itisnotdescribedas"mainstay".Fortoomuch.Inthecampusnetworkandmetropolitanareaeducationnetwork,thebackbonenetwork,metropolitanareanetworkbackbone,andconvergencelayerallhavethree-layerswitches.Especiallythecorebackbonenetworkmustusethree-layerswitches,otherwisetheentirenetworkhasthousandsofunits.Allofthecomputersareinthesamesubnet.Notonlyaretherenosecurityatall,butalsothebroadcaststormcannotbeisolatedbecausethebroadcastdomaincannotbedivided.Ifatraditionalrouterisused,althoughthebroadcastcanbeisolated,theperformancecannotbeguaranteed.Theperformanceofthethree-layerswitchisveryhigh,withboththefunctionofthethree-layerroutingandthenetworkspeedofthetwo-layerswitching.Layer2switchingisbasedonMACaddressing,andLayer3switchingistoforwardserviceflowsbasedonLayer3addresses;inadditiontothenecessaryroutingdecisionprocess,mostofthedataforwardingprocessishandledbyLayer2switching,whichimprovestheefficiencyofpacketforwarding..Thethree-layerswitchrealizestheroutingfunctionofIPthroughtheuseofahardwareswitchingmechanism,anditsoptimizedroutingsoftwareimprovestheefficiencyoftheroutingprocessandsolvesthespeedproblemoftraditionalroutersoftwarerouting.Therefore,itcanbesaidthatthethree-layerswitchhas"thefunctionofarouterandtheperformanceofaswitch."
2.Превключването на слой 3 е задължително за свързване на подмрежи.
Iftherearemorethanacertainnumberofcomputersonthesamenetwork(usuallyaround200,dependingonthecommunicationprotocol),itislikelytobeBecauseofthelargenumberofbroadcastsonthenetwork,thenetworktransmissionefficiencyislow.Inordertoavoidbroadcastingstormscausedbybroadcastingonlargeswitches,itcanbefurtherdividedintomultiplevirtualnetworks(VLANs).Butdoingsowillcauseaproblem:thecommunicationbetweenVLANsmustbeimplementedthroughrouters.However,traditionalroutersarealsodifficulttohandlethecommunicationtasksbetweenVLANs,becausetheroutingcapabilitiesoftraditionalordinaryroutersaretooweakcomparedtothenetworktrafficofthelocalareanetwork.Andthepriceofgigabitroutersisalsoveryunacceptable.IfyouuseGigabitportsor100MportsonaLayer3switchtoconnecttodifferentsubnetsorVLANs,youcaneconomicallysolvetheproblemofrelyingonroutersforcommunicationbetweensubnetsaftersubnettingwhilemaintainingperformance.Therefore,thethree-layerswitchisanidealdeviceforconnectingsubnets.
Advantages
Inadditiontoexcellentperformance,thethree-layerswitchalsohassomefeaturesthatthetraditionaltwo-layerswitchdoesnothave.Thesefeaturescanbeusedfortheconstructionofcampusnetworksandmetropolitaneducationnetworks.Itbringsmanybenefits,listedasfollows:
1, висока мащабируемост
Whenthethree-layerswitchisconnectedtomultiplesubnets,thesubnetonlyestablishesalogicalconnectionwiththethird-layerswitchmodule,Unliketraditionalexternalroutersthatneedtoincreaseports,therebyprotectingusers'investmentincampusnetworksandmetropolitaneducationnetworks.Andtomeettheneedsoftheschool'srapidgrowthinnetworkapplicationsin3to5years.
2.Висока производителност
Thethree-layerswitchhastheabilitytoconnecttolarge-scalenetworks,andthefunctioncanbasicallyreplacesometraditionalrouters,butthepriceisclosetothetwo-layerswitch.Thepriceofa100MLayer3switchisonlytensofthousands,whichissimilartothepriceofahigh-endLayer2switch.
3. Вграден механизъм за незащитеност
Thethree-layerswitchcanbethesameasanordinaryrouter,withthefunctionofaccesslist,whichcanrealizeone-wayortwo-waycommunicationbetweendifferentVLANs.Ifyousetitintheaccesslist,youcanrestrictusersfromaccessingspecificIPaddresses,sothattheschoolcanprohibitstudentsfromaccessingunhealthysites.Theaccesslistcanbeusednotonlytoprohibitinternalusersfromaccessingcertainsites,butalsotopreventillegalusersoutsidethecampusnetworkandmetropolitanareaeducationnetworkfromaccessingtheinternalnetworkresourcesofthecampusnetworkandmetropolitanareaeducationnetwork,therebyimprovingnetworksecurity.
4. Подходяща форма за мултимедийно предаване
Educationnetworkoftenneedstotransmitmultimediainformation,whichisafeatureofeducationnetwork.Thethree-layerswitchhasaQoS(QualityofService)controlfunction,whichcanallocatedifferentbandwidthstodifferentapplications.Forexample,whentransmittingvideostreamsoncampusnetworksandmetropolitaneducationnetworks,acertainamountofdedicatedbandwidthcanbereservedforvideotransmission,whichisequivalenttoopeningupdedicatedchannelsinthenetwork,andotherapplicationscannotoccupythesereservedbandwidths.Bandwidth,soitcanensurethestabilityofvideostreaming.TheordinaryLayer2switchdoesnothavethisfeature,sowhenthevideodataistransmitted,thevideojitterphenomenonwilloccursuddenlyandslowly.
Inaddition,video-on-demand(VOD)isalsoafrequentlyusedserviceineducationnetworks.However,becausesomeVODsystemsusebroadcasttotransmit,andbroadcastpacketscannotbeimplementedacrossnetworksegments,VODcannotbeimplementedacrossnetworksegments;ifVODisimplementedinunicastform,althoughitcanbeimplementedacrossnetworksegments,itsupportsAtthesametime,thenumberofconnectionsisverysmall,generallydozensofconnectionsoccupyallbandwidth.Thethree-layerswitchhasamulticastfunction,andVODdatapacketsaresenttoeachsubnetintheformofmulticast,whichnotonlyrealizescross-networksegmenttransmission,butalsoensurestheperformanceofVOD.5.BillingfunctionIncollegecampusnetworksandmetropolitaneducationnetworksinsomeareas,thereislikelytobebillingrequirements,becausethethree-layerswitchcanidentifytheIPaddressinformationinthedatapacket,soitcancountthedatatrafficofthecomputerinthenetwork,Youcanchargeaccordingtotheflow,youcanalsocountthetimethecomputerisconnectedtothenetwork,andchargeaccordingtothetime.ItisdifficultforordinaryLayer2switchestodobothatthesametime.
Whentheupsurgeofbuildingcampusnetworksandmetropolitanareaeducationnetworksissetoffacrossthecountry,Ibelievethatthethree-layerswitchwithitsexcellentperformanceandmoderatepricewillsurelymakeabigdifferenceinthisupsurge.
Controller
Reasons
NetworktrafficcontrollerbitSaver(alsoknownasapplicationtrafficmanager,bandwidthmanagerorQoSdevice)asearlyas2000Ithasappeared,andwasfirstdevelopedbyPackteerintheUnitedStates.However,sincetheproblemofnetworkbandwidthhasnotyetbeensignificant,enterpriseITdepartmentsarenotpayingenoughattentiontobandwidth.Withtheapplicationofvariousnewnetworktechnologiesandthedevelopmentofnetworkmultimediatechnology,theproblemofnetworkbandwidthshortageisbecomingmoreandmoreobvious.Especiallysince2005,P2Papplicationshavebroughtaseriousthreattobandwidthmanagement,sothebandwidthmanagermarkethasbeengreatlydeveloped.Accordingtoincompletestatistics,thismarkethasexceedednearly2.5billionUSdollars.China'sbandwidthmanagementmarkethasonlygraduallyreceivedattentionsince2004.In2007,China'sbandwidthmanagementmarketsharewasalso200millionyuan.ItisexpectedthatChina'sbandwidthmanagementmarketwillgrowatarateofmorethan20%.InadditiontoforeignPackteerandAllotcompanieswithbandwidthmanagementequipmentproviders,domesticmanufacturerssuchasBeijingYingzhixingda,ChanxunTechnology,etc.,bandwidthmanagementequipmentofforeignmanufacturershavenotyetrealizedthelocalizationoftheinterface,andtheyareallenteredintheformofauthorizedagents.China:Domesticmanufacturershavegonethroughthreetofouryearsofproductresearchanddevelopment,andtheirproductshavebecomeincreasinglystable.Themarket,technology,andproductcompetitionwillbeginin2008.
Basicfunctions
Thebasicfunctionofthebandwidthmanagerisverysimple,whichistoallocateandmonitorbandwidthaccordingtoapplicationsandusers.Becauseitisaseven-layernetworkmanagementdevice,networkmanagerscandirectlyallocatebandwidthtoapplicationsanduserswithouthavinghighnetworkknowledge,whichreducestheinvestmentofnetworkmanagerstoacertainextent.Althoughthefunctionisverysimple,therearemanyapplicationsthatcanbeimplemented,butmostusersdonothaveagoodunderstandingofbandwidthmanagementapplications.ForeignbandwidthmanagementequipmentisexpensiveanddoesnotsupportChinesedisplay.Therefore,theapplicationsofPackteerandAllotaremainlyconcentratedintelecommunicationsandfinance.AlthoughdomesticmanufacturerssuchasBeijingYingzhixingdahavemadegainsineducation,government,energyandmedicalindustries,theirproductseriesIthasonlybeenformedforoneyear,sovendorsdidnotinvesttoomuchinthepromotionofmarketapplications,resultinginusers'applicationofbandwidthmanagementinitsinfancy.
ApplicationScope
BandwidthapplicationsinthetelecommunicationsandfinancialfieldsaremainlymanifestedinSLA(ServiceLevelAgreement),throughbandwidthmanagementequipmenttoprovidedifferentlevelsofbandwidthservicestousersofdifferentlevels,Soastoguaranteethereturnoninvestmentofcorecustomers.
Ineducation,governmentandotherapplications,thebandwidthmanagermainlyfocusesonthemanagementofP2P,especiallythemanagementofBT.Atthesametime,bandwidthmanagementequipmenthasalsobeguntoappearasaQoSguaranteeequipmentforvideoconferencing.AstheclientsofP2Pandotherapplicationsarecontinuouslyupgraded,onlydomesticproductswithindependentresearchanddevelopmentcanrealizetherapidlaunchofmanagementstrategiesaccordingtothenewversion.Inthisapplication,internationalmanufacturershavenoadvantage.
Разбира се, като мениджър на честотна лента, той също има повече приложения. Като следните приложения:
First,thetransparencyofnetworkapplications,throughthebandwidthmanager,thestatusofpreviouslyunknownnetworkapplicationscanbeviewedindetail.
Second,preventsuddensurgeintrafficandattacksfromunknownapplications,suchasDoSattacks,toensurenetworksecurity.
3.Evaluatethevalueofcoreapplications,andunderstandtheutilizationandefficiencyofcoreapplicationsthroughmonitoringofcoreapplicationtraffic.
Четири. Уверете се, че честотната лента е необходима от приложенията за ключове (като CRM, VPN, безжична мрежа, видеоконференции, VoIP и др.), за да сте сигурни, че приложенията за ключове не са блокирани по всяко време
5.Accuratelyevaluatetheloadcapacityofthenetworkandtheimpactofnewapplicationsontheoverallnetworkapplicationstoensuretherationalityofthecustomer'sITinvestment.
Six.Realizetheprovisionofdifferentnetworkresourceallocationsaccordingtotheuser'sleveltoensurethenetworkvalueofthecoreusersofthecustomer.
Seven.Reducetherepetitiveoperationsofnetworkmanagersandprovidequantitativedataforapplications,sothatthemanagementcanmakedecisionsbasedontheapplicationstatus.
Theseapplicationsonlyappearinsomespecificcases,andmostusershavenoteffectivelyintegratedbandwidthmanagementwiththeirownnetworkmanagement.Theapplicationprospectsaregreat.
Flowcontrolinthenetwork
Methodstoincreasetheuser'savailableresources:choosethepathreasonably,makethepathlessoptimalwhentheloadislight,andmorediversionwhentheloadisheavy;Increasethenumberofhierarchicalconnectionsandshuntconnectionsunderheavyload;increasechannelloans;increaseinformationrate;appropriatelyincreasebuffers,etc.Waystoreduceusers'demandforresources:rejectcertainservicerequests;requireuserstoreducetheload;reasonablyallocateusers'useofresources,suchasusingreservations,polling,andpriority.Theessenceofreducingtheuser'sdemandforresourcesistoreducetheservicelevelandquality,ortoprovideservicesinareasonablemanner.
Inmanycomputernetworks,thewidelyusedflowcontrolmethodisbasedonreducinguserdemand.Thefollowingisacentralizedflowcontrolmethod:
1.Waitingfortransmissionmethod.Itisalsocalledsuppressedsendingmode.Whenthebufferofthereceivingnodehasbeenoccupiedalotandthenodeentersthedangerousstageofdeadlock,thesendingnodewillsendamessagetosuspendsending,andwhenthedangerousstageislifted,thesendingwillbenotifiedtosuspendsending.Thenode,resumedatatransmission.
2.Reservebuffermode.Beforestartingdatatransmission,thesourcehostmustfirstunderstandtheavailablebuffersofthedestinationhost,reservethebuffer,andthencontrolitsowndatatransmissionaccordingtothebufferallocatedbythedestinationhost.Whenthebufferisusedup,waitfortheotherpartytoallocatethebufferagainbeforecontinuingtosend.
3.Метод на лиценза.
4.Метод за изхвърляне на единица данни.