Въведение
Itissuitableforthecommunicationbetweencomputersandcomputers,computersandterminals,andterminalsandterminalsofdifferenttypesandspeeds,soastorealizethesharingofinformationresourcesstoredinthecomputer.Atthesametime,variousvalue-addedservicescanbedevelopedonthepacket-switcheddatanetwork[1].
Предимства
1.Множествената комуникация може да се реализира, значително подобрявайки използването на линията;
2.Hightransmissionrate,safeandreliableinformationtransmission;
3.Thechargehasnothingtodowiththedistance,anditischargedaccordingtotheamountofinformationandtimeofuse,whichshowsincomparablesuperiorityforremotecommunication;
4. Силни възможности за откриване и коригиране на грешки; кандидатстване за акаунт, парола (NUI), може да реализира национален роуминг.
Предоставяне на услуги
3.1 Основен бизнес
1.Switchedvirtualcircuit(SVC):Itcancommunicatewithdifferentusersatthesametime,whichisconvenientandflexible.TwodataWhentheterminalwantstocommunicate,usethecallingprogramtoestablishthevirtualcircuitfirst,andusethereleaseprogramtoreleasethevirtualcircuitafterthecommunicationends.Avirtualcircuitisalogicalconnectionbetweentwodataterminalsincommunication.Itisonthetrunklinebetweenitssubscriberlineandtheswitch.Accordingtotheneedsofthemessage,itoccupiesmultipletimeslotsintheunitofpacketlengthandthecorrespondingswitchintheswitch.storage.Thevirtualcallserviceprovidesreliabledeliveryofpacketsanddeliversthemtotheuserinthesameorderasthepacketsreceivedbythenetwork.
2.Permanentvirtualcircuit(PVC):Itcanestablishafixedconnectionwithoneormoreusers.Permanentvirtualcircuit(PVC)providesapermanentlogicalconnectionfortwodataterminalsinthepacketnetworkduringtheappliedcontractperiod,withouttheneedforcallestablishmentandreleaseprocedures,andisthesameasVCinthedatatransmissionstage.
3.2 Допълнителни бизнес функции
1.Closedusergroup(CUG):Communicationislimitedtospecificuserstoavoidinterferencefromoutsiders.
2.NetworkUserIdentity (NUI): Осигурява строги гаранции за сигурност и може да реализира широкообхватен роуминг.
3. Услуга за излъчване: еднопосочно предаване на информация от точка към много точки.
4. Обратно таксуване: извиканата страна плаща.
5.Quickselection:Thiskindofbusinessissuitableforbankwithdrawalbusiness,butbothpartiesmustbeuserswhocanacceptthequickselectionbusiness.
6. Блокиране на входящи/изходящи повиквания: Потребителят не получава повиквания/изходящи повиквания в рамките на определен период от време, но може да извършва изходящи повиквания/получава входящи повиквания.
7.Callforwarding:Whentheuserisbusyorfails,theswitchautomaticallytransferstheuser'scalltothenumberreservedbytheuser.
8.Searchgroup(HG):Whenauserhasmultiplelinesconnectedtothenetwork,balancetheloadoneachlineinordertoincreasethecall-throughratewhenthecustomeriscalled.
3.3 Нови бизнес функции
1.FrameRelay(FrameRelay): Осигурява по-висока скорост на комуникация за реализиране на глас, данни и данни за изображения.
2.Comprehensivetransmission;informationcardverificationservice(POS):simultaneoustransmissionofdataonatelephonelinewithoutmutualinterference,2-3timesfasterthantraditionalPOSservices;
3.Виртуална частна мрежа;
4.SNAмрежова среда;
5.функция Token-ringLANsmartbridge;
6.Асинхронен интерфейс за запитване (APT).
Допълнителни услуги по избор от потребителите
Therearetwotypesofsupplementaryservicesoptionalbyusers.Supplementaryservicesonacallbasis.Theformerhasextendedpacketsequencenumbers(modulo128),non-standarddefaultwindowsize,non-standarddefaultpacketlength,closedusergroupacceptanceofreversebillingandacceptanceofquickselectionitems;thelatterhasclosedusergroupselection,reverseQuickselectionofbillingandabbreviatedcalls.
Обхват на приложение
Банкиране, застраховане, ценни книжа; митници; данъци; търговия на дребно; други компании, предприятия и институции, които трябва да реализират компютърна мрежа;
Тонгда Местоположение
1. Повечето от държавата, градове над ниво град и някои общини и градове на ниво окръг.
2. Международен включва Хонконг, Макао, Тайван, Европа, Америка, Япония и други страни и региони.
Състав на оборудването
Thepacket-switcheddatanetworkiscomposedofpacketswitches,networkmanagementcenters,remoteconcentrators,sub-assemblyanddisassemblyequipment,andtransmissionequipment.
Packetswitch:Themainfunctionistorealizetheinterfaceprotocol(X.25)betweenthedataterminalandtheswitch,thesignalingprotocolbetweentheswitches(suchasX.75),andprovidestorageandforwardinginpacketmodeSupportspacketnetworkservices,andcooperateswiththenetworkmanagementcentertocompleteroutingmonitoring,billing,control,etc.Accordingtothestatusofthepacketswitchinthenetwork,itcanbedividedintotwotypes:transitswitchandlocalswitch.Theformerismainlyusedtocompletethestorageandforwardingofpacketsbetweenswitchesinthepacketbackbonenetwork,andthelattermainlycompletestheuserinterfaceandlocalswitchingfunctions.Accordingtothecapacityofpacketprocessingcapacityandthenumberofports,therearelarge,mediumandsmallcapacityswitches.Thelarge-capacitypacketswitchcanprocesstensofthousandsofpacketspersecondandhasthousandsofports;thesmall-capacitypacketswitchcanprocesshundredsofpacketspersecondandhasdozensofports.
NetworkManagementCenter:cooperatewiththepacketswitchtoensurethenormaloperationofthenetwork.Thenetworkmanagementcentercanbedividedbyareaandfunction,withoneormore.Itsmainfunctionsincludenetworkmanagement,usermanagement,measurementmanagement,billingmanagement,operationandmaintenancemanagement,routingmanagement,collectingpartialorentirenetworkstatisticalinformation,andnecessarycontrolfunctions.
Padassemblyanddisassemblyequipment(PAD):Themainfunctionistoconvertthenon-packetformatofordinarycharacterterminalsintoagroupformat,andgroupthecharacterdatastreamsofeachterminalintogroups,whichareinterleavedandmultiplexedontheaggregatechannel.,Theotherpartythenconvertsthereceivedpacketformatintheoppositedirection.TheuserportsofsomePADsalsohaveinterfacessuchasX.20,SDLC,etc.,therebyallowingcorrespondingsynchronousterminalstoaccessthePAD.Itsfunctioncanberealizedintheswitch,andcanalsoberealizedbyaseparatedevice.
RemoteConcentrator:Itsfunctionissimilartothatofapacketswitch.ItusuallycontainsthefunctionofPAD,butitcanonlybeconnectedtoapacketswitch,sonoroutingfunctionisneeded.Someconcentratorscanalsobeconnectedtotwopacketswitches,sotheyhavesimpleroutingfunctionsandlocalswitchingfunctions.Itismainlyusedforsynchronousandasynchronousdataterminalsfarawayfromthepacketswitchtoaccessthepacketdatanetworktoreducethelinecostandoccupymorepacketswitchports.