Metropolitan Area Network

Definition

Thetypicalapplicationofmetropolitanareanetworkisbroadbandmetropolitanareanetwork,whichisbasedonIPandATMtelecommunicationstechnologywithinacity,andopticalfiberisusedasthetransmissionmediumtocollectdata.Ahigh-bandwidth,multi-functional,multi-servicemultimediacommunicationnetworkthatintegratesvoiceandvideoservices.

Broadbandmetropolitanareanetworkscanmeetthegrowingdemandforhigh-speedandhigh-qualitydatacommunicationservicesfromgovernmentagencies,financeandinsurance,universities,schools,companiesandenterprises,especiallytherapidlydevelopingInternetusergroupThedemandforbroadbandhigh-speedInternetaccess.

Thedevelopmentofbroadbandmetropolitanareanetworkshasgonethroughalongperiodoftime,fromtraditionalvoiceservicestoimageandvideoservices,frombasicaudio-visualservicestovariousvalue-addedservices,from64kb/sThebasicservicesto2.5Gb/s,10Gb/sandotherleasedlineservices.Withthedevelopmentoftechnologyandthecontinuousincreaseindemand,thetypesofservicesarealsoconstantlyevolvingandchanging.

mycountry’sgraduallyimprovedurbanbroadbandmetropolitanareanetworkhasbroughtalotofconveniencetoourlives,suchashigh-speedInternetaccess,videoondemand,videocalls,InternetTV,distanceeducation,teleconference,etc.WeareusingBehindallkindsofInternetapplications,itisthemetropolitanareanetworkthatplaysahugerole.

Thelocalareanetworkorthewideareanetworkisusuallyforaunitorsystemservice,andthemetropolitanareanetworkisfortheentirecityratherthanforaspecificdepartment.

Theconstructionoflocalareanetworkorwideareanetworkincludestwoaspects:resourcesubnetandcommunicationsubnet,whiletheconstructionofmetropolitanareanetworkmainlyfocusesoncommunicationsubnet,whichalsocontainstwoaspects:

  1. Oneistheurbanbackbonenetwork,whichisconnectedtoChina'sbackbonenetwork.

  2. Thesecondistheurbanaccessnetwork,whichconnectsalllocalnetworkuserswiththeurbanbackbonenetwork.

Composition

Themetropolitanareanetworkisdividedinto3levels:corelayer,convergencelayerandaccesslayer:

  1. Thecorelayermainlyprovideshigh-bandwidthservicebearerandtransmission,completestheinterconnectionwithexistingnetworks(suchasATM,FR,DDN,IPnetwork),andischaracterizedbybroadbandtransmissionandhigh-speeddispatch.

  2. Themainfunctionoftheaggregationlayeristoprovidetheserviceaccessnodewiththeaggregationanddistributionofuserservicedata,andatthesametimetorealizetheservicelevelclassificationoftheservice.

  3. Theaccesslayerusesavarietyofaccesstechnologiestoallocatebandwidthandservicestoachieveuseraccess.Theaccessnodeequipmentcompletesthemultiplexingandtransmissionofmultipleservices.

Features

Transmissionrate

Broadbandmetropolitanareanetworkadoptslarge-capacityPacketOverSDHTransmissiontechnologyprovidestransmissionguaranteeforhigh-speedroutingandswitching.ThewidespreadapplicationofGigabitEthernettechnologyinthebroadbandmetropolitanareanetworkenablestheportsofthebackboneroutertobeefficientlyextendedtothedistributionlayerswitchesatahighspeed.Opticalfiber,networkcabletotheuserdesktop,sothatthedatatransmissionspeedcanreach100M,1000M.

Lowinvestmentandsimple

Broadbandmetropolitanareanetworkclientequipmentischeapandpopular,androuters,HUBsandevenordinarynetworkcardscanbeused.Theuseronlyneedstoproperlyconnecttheopticalfiberandnetworkcable,andsimplyconfiguretherelevantparametersoftheuser'snetworkcardorroutertoaccessthebroadbandmetropolitanareanetwork.IndividualusersonlyneedtoinstallanEthernetcardontheircomputer,andinserttheinterfaceofthebroadbandmetropolitanareanetworkintothenetworkcardtoconnecttothenetwork.Theinstallationprocessisthesameastheprevioustelephone,exceptthatthenetworkcablereplacesthetelephoneline,andthecomputerreplacesthetelephone.

Advancedtechnology

Technically,itprovidesuserswithahighlysecureserviceguarantee.ThebroadbandmetropolitanareanetworkprovidesthesecondlayerofVLANisolationinthenetworktoensuresecurity.DuetothesecurityofVLAN,onlycomputersintheuser'slocalareanetworkcanaccesseachother,andnocomputerinthenon-user'slocalareanetworkcanaccesstheuser'scomputerthroughabnormalchannels.Ifyouwanttoaccessfromoutsidethenetwork,youmustpassthroughthenormalroutingandsecuritysystem.Therefore,itisimpossibleforhackerstousetheunderlyingvulnerabilitiestodamage.Ordinaryusersofvirtualdial-upaccesstheInternetthroughthebroadbandaccessserver,andcanaccesstheInternetonlyaftertheverificationoftheaccountandpassword.TheusercanconvenientlycontrolthetimeandplaceoftheInternetbyhimself.

Directconnectiontechnology

OpticalfiberdirectconnectiontechnologyreferstothedirectconnectionofIPmetropolitanareanetworkequipmentsuchasEthernetswitches,routers,andATMswitchesthroughopticalfibers.Strictlyspeaking,thisisnotametropolitanareatransmissionsolution,butbecausemanyopticalfiberdirectconnectionschemeshavebeenadoptedintheIPmetropolitanareanetwork,wewillintroduceopticalfiberdirectconnectionasatransmissiontechnologyhere.

TheopticalinterfaceoftheIPmetropolitanareanetworkequipmentisdirectlyconnectedinapoint-to-pointmanner,andtheserviceaccessequipmentisalsodirectlyconnectedtothebackboneequipmentthroughanopticalfiber.Theopticalfiberdirectconnectiontechnologyabandonsthetransmissionequipment,thesolutionissimple,andthecostislow,butithasobviousshortcomings:First,becausethereisnotransmissionlayer,theopticalfiberquality,performancemonitoringandprotectioncannotberealized.

Secondly,theutilizationrateofopticalfiberislow,andthewasteisserious.Everytwoserviceaccesspointsneedapairofopticalfibers.Ifaservicecontacthasbusinessintercommunicationwithotherservicecontacts,thenumberofopticalfiberswillincreasefactorially.Finally,theserviceportisunderpressure.Everytimeanewnodeisadded,anIPmetropolitanareanetworkdevicesuchasaswitchorrouterneedstoaddanaccessport.Therefore,thismethodisonlysuitableforoccasionssuchaslocalareanetworkswherethenumberofnodesisnotmanyorthedistancebetweennodesisrelativelyclose.

TransportPlatform

Metropolitan Area Network

SinceSDH/SONEThasalreadyaccountedforaverylargeshareofthetransmissionnetwork,itwillinevitablybeintheIPmetropolitanareanetworkrepresentedbydatacommunicationPlayanimportantrole.Basedonthecomprehensiveconsiderationoftechnologymaturity,reliabilityandoverallcost,SDH/SONET-basedmulti-servicesolutionswillstillplayanimportantroleintheforeseeablefuture,whichisparticularlyprominentinthemetropolitanareanetworkapplicationfield..

SDH/SONETloophasuniqueadvantagesinnetworkperformancemonitoring,failurerecoveryandreliability.Itisverysuitablefortheneedsoftime-sensitivevoiceservicesandmeetsthehigh-performancerequirementsoftelecommunicationlevel.However,SDH/SONETisanarchitecturecharacterizedbycomplexcentralizedsupplyandlimitedscalability,anditisdifficulttohandleIPservicescharacterizedbysuddennessandimbalance.

SDH/SONETtechnologyitselfisalsoconstantlydeveloping,theuniqueadvantagesofSDH/SONETtechnologywillcontinuetobemaintained,anditwillcontinuetobeAndEthernettransparenttransmission.

ThemodifiedSDH/SONETfunctionalmodulesfirstlymapmultiplebusinessadaptationstodifferentVCsbyeachbusinessinterfacemodule,andthendeploythemthroughhigh-andlow-levelcrossmatricestoachievebranchtobranch.Road,branch-to-line,line-to-linefullcrossconnection.Infact,themodifiedSDH/SONETequipmenthasalreadybrokenthroughthepreviousADMmodel.Thereisnodifferenceinspeedbetweenbranchesandlines,butonlydefinedaccordingtotheflowofbusiness.Onthenew-generationSDH/SONETplatform,multiplexers,splitters,wavelengthconverters,etc.canalsobeaddedtosupportDWDMapplications.

ThetransformedSDH/SONETisalsocalledtheMulti-ServiceTransportPlatform(MSTP),asshowninFigure3.Onthisplatform,TDMservices,ATMservices,andIPservicescanallbeaccessedandcanbetransmittedefficiently;furthermore,thethreetypesofservicescanalsobecrossedandexchanged.Therefore,theadvantagesofthemulti-servicetransportplatform(MSTP)areveryobvious.ItcannotonlybecompatiblewithalargenumberofapplicationsofTDMservices,butalsomeettheincreasingrequirementsofdataservices(IP,ATM).Atthesametime,itadoptsthemostmatureSDHnetworkingandProtectiontechnology.

MSTPtechnologyisacompromisesolution,itbettersolvesthecontradictionwhenoperatorsneedtotransmitTDMservices,butalsoneedtodealwithdataservices.ItisalsoalargenumberofSDHequipmentinstalledbyoperators.Underoperatingconditions,evolveitsownnetworktoprovideuserswithabetterchoiceforemergingservices.However,whendealingwithalargenumberoforpureIPservices,MSTPalsohasdefectssuchasinabilitytodynamicallyandfairlyallocatebandwidth.

Purpose

High-speedInternetaccess

High-speedInternet-usingbroadbandIPnetworkfrequencybandwidthandhighspeedcharacteristics,userscanquicklyAccesstheInternetandenjoyallrelatedInternetservices(includingWWW,e-mail,newsgroups,BBS,Internetnavigation,informationsearch,remotefiletransfer,etc.),andtheportspeedcanreachmorethan10M.Interactivegames-"InteractiveGameNetwork"allowsyoutoenjoyanewgameexperiencecombiningInternetonlinegamesandLANgames.Throughthebroadbandnetwork,evennetizensinthesamecitywhoareseparatedby100kilometerscanmeetandplay3Donlinegamesregardlessoftraffic.

VideoonDemand

VODvideoondemand-allowsyoutositathomeandusetheWEBbrowsertobroadcastyourfavoriteprogramsatwill,includingmovieboutiques,PopularTVseries,aswellasvideonews,sportsprograms,Chineseoperasongsanddances,MTV,karaoke,etc.

NetworkTV

NetworkTV(NETTV)—breaksthroughthetraditionalTVmodel,crossestheconstraintsoftimeandspace,andrealizesTVwithunlimitedchannelsontheInternetRatings.WatchingTVprogramsdirectlyfromtheInternetthroughaWEBbrowserovercomesthedisadvantagesofexistingTVchannelsthatareconstrainedbyvariousfactorssuchasregionsandclimates,andisconducivetotheproductionandbroadcastingofanewtypeofinteractiveTVseries"InternetTVseries".

Telemedicine

Telemedicine-usingadvanceddigitalprocessingtechnologyandbroadbandcommunicationtechnology,medicalpersonnelarefarawayfromhundredsofkilometersorthousandsofkilometersDiagnosisandtreatmentofpatientsoutside,telemedicineisanewmedicalmethoddevelopedwiththeriseofbroadbandmultimediacommunications.

Remoteconferences-thereisnoneedtotravelorgooutformeetingsindifferentplaces.Inthevideoconferencesystemonthehigh-speedinformationnetwork,thefeelingof"theworldisclosetoeachother"hasbeenthemostperfectinterpretation.

Distanceeducation

Distanceeducation-fundamentallyovercomestheone-waybroadcastbasedonTVtechnology,thetextquerybasedonWEBpagesandThedisadvantagesofthethreemethods,suchastheconferenceTV,whichistooexpensivetoenterthehome,usethelatestbroadbandnetworkproductsandtechnologiestointeractivelyenterthemultimediainformationsuchaspictures,texts,andsoundintoordinaryhomes,schools,enterprisesandinstitutions.StudentscanpassBroadbandnetworktowatchteachingprogramsathomeandinteractwiththeteacherinrealtime;youcancheckinformationontheInternet,assignhomework,handinhomework,answerquestions,etc.byEmail,etc.;youcansearchthecoursedatabaseandplaytheteacher'slecturevideoinVODmode..

Remotemonitoring

Remotemonitoring(WEBCAM)-monitorremotesystemsorotherthings,andauthorizeduserstofreelyrotatethelensthroughWEB,Focusingandotheroperationstoachievereal-timemonitoringandmanagementfunctions.Themonitoringsystemadoptsdigitalmonitoringmethod.Thedigitalmonitoringmethodiswellintegratedwiththecomputernetworktogivefullplaytothebandwidthadvantageofthebroadbandmetropolitanareanetwork.Thisisapopulartrendinthedevelopmentofsurveillancesystemsinthefuture.

TradingSystem

FamilySecuritiesTradingSystem-youcaninteractivelyconductonlinestocktradingintheformoflargesecuritiesaccountsathome,notonlycanyouchecktheShenzhen,Shanghaistockmarketquotations,comprehensiveandtimelyfinancialinformationcanbeobtained,real-timeanalysiscanalsobecarriedoutthroughavarietyofanalysistools,andreal-timeonlineorderscanbeplacedonline,refertoexpertstockreviews.

Broadbandbusiness

Audioondemandandmanyotherservices.

Prospects

Withthedevelopmentoftechnologyandthecontinuousincreaseindemand,thetypesofservicesarealsoconstantlyevolvingandchanging.Fromtraditionalvoiceservicestoimageandvideoservices,frombasicFromaudio-visualservicestovariousvalue-addedservices,from64kb/sbasicservicesto2.5Gb/s/10Gb/sleasedlineservices,variousservicesemergeinendlessly.Differentserviceshavedifferentbandwidthrequirementsanddifferentservicerequirements.

Fromtheperspectiveofservicequality(QoS),servicescanberoughlydividedintothefollowingtypes:high-qualityvoiceservicesandvideoservices;VIPcustomerdedicatedlines;datacommunicationnetwork(DCN)dataBusiness;variousdatavalue-addedservices;Internetservices.

Eachtypeofbusinessrequiresdifferentservicelevelsanddifferentsecurityprotectionlevels.WiththecontinuousdevelopmentofInternetservicesandvariousvalue-addedservices,thebandwidthrequiredbythemetropolitanareanetworkhasbecomewiderandwider,andthecurrentmetropolitanareanetworkhasbecomea"bottleneck"forbusinessdevelopment.Inaddition,multipletypesofserviceshaveputforwardhigherrequirementsfortheintegratedaccessandprocessingofthemetropolitanareanetwork.Ingeneral,packetizationandbroadbandizationarebusinessdevelopmenttrends.

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