China Public Computer Internet

Structure

ChinaNetisChina’slargestInternetserviceprovider.ChinaNetisapartoftheInternetinChina.ItadoptstheTCP/IPprotocolstructureandisconnectedtotheinternationalInternetthroughahigh-speeddigitaldedicatedline.

ChinaNetisaveritablebackbonenetworkofthedomesticcomputerInternet.ThetopologicalstructureofChinaNetbackbonenetworkisdividedintocorelayerandregionallayer.Thecorelayeriscomposedofcorenodesin8cities:Beijing,Shanghai,Guangzhou,Shenyang,Nanjing,Wuhan,ChengduandXi'an,andprovidesinterconnectionwiththeinternationalInternetandinformationexchangechannelsbetweenregions.EachofthethreecorenodesinBeijing,ShanghaiandGuangzhouhastwointernationalexportroutersconnectedtotheInternet.

ChinaNethasnowopenedinternationalexportcircuitstotheUnitedStates,Europeancountries,andAsiancountries.ChinaNetprovidesallservicesontheInternet.Amongthem,E-MailandWWWbrowsingarewidelyusedbyusers.ChinaNetprovidesTelnet,FTP,FINGER,USENET,TALK,CHATandotherservices.

ChinaNetisbasedonthemodernChinaTelecom.Allcitieswithaccesstotelecommunicationnetworks(ChinaPublicDigitalDataNetwork,ChinaPublicSwitchedDataNetwork,ChinaPublicFrameRelayBroadbandServiceNetworkandTelephoneNetwork)canpassChinaNetconnectstotheInternetandenjoysInternetservices.ChinaNet'sservicesinclude:Internetaccessservices,applyforIPaddressesanddomainnamesonbehalfofusers,rentroutersandsupportingtransmissionequipment,providedomainnamebackupservices,technicalservicesandapplicationtraining.

Networkstructure

ChinaNet'snetworkstructureisdividedintobackbonelayerandaccesslayer.

1.Backbonelayer

ThebackbonelayerofChinaNetiscomposedofbackbonelayernodesandcommunicationlines.Thebasicrequirementsforthebackbonelayerare:provideconnectionwithinternationalanddomesticInternet;provideChinaNet'shigh-speedbonethousanddatachannel;provideconnectionsbetweenChinaNet'svariousaccessnetworks;ensurehighreliability,highspeed,andlowlatencyrequirements;Dependingonbusinessneeds,itcandirectlyprovideconnectionstolargeusernetworks.

Thebasicprincipleofconnectionbetweenbackbonelayernodesis:thereareatleast3reachableroutesbetweenanypairofbackbonelayernodes;dependingonbusinessneeds,thedensityofconnectionsbetweenbackbonelayernodescanbereasonablyadjusteduntilFullmeshconnection;theconnectionbetweenthebackbonelayernodesuseshigh-speed,high-qualitycommunicationlinesasfaraspossible,andthetransmissionrateisdeterminedbybusinessneeds;multiplebackupcommunicationlinescanbesetbetweenanypairofbackbonelayernodes.

2.Accesslayer

Thebasicrequirementsfortheconnectionbetweenthenodesinthehumannetworkandtheconnectionwiththebackbonelayerare:inprinciple,anynodeinanaccessnetworkatleastConnecttoatleasttwoothernodesinthenetworkthroughtwodirectroutes;atleasttwonodesinanaccessnetworkareconnectedtoatleasttwonodesintheunderlyinglayerthroughdirectroutes;'connectionswithhighertransmissionqualityshouldbeusedasmuchaspossibleForcommunicationlines,thetransmissionratedependsonbusinessneeds;anyconnectioncanbeappropriatelyconfiguredwithabackupcommunicationlinedependingonbusinessneeds.

Networkfeatures

1.Thenetworkissafeandreliable.AnynodeoftheChinaNetnetworkhasmorethantworelaylines,andthemainnodeequipmentadoptsdualbackupequipment,soastoensurethatanynetworkbusinesswillnotbeinterruptedwhensomeequipmentorlinesinthenetworkfail.Atthesametime,inordertoensurethesecurityofthenetwork,ChinaNetadoptsadvancedsecuritytechniquestopreventvariousonlineattacks.

2.Thenetworkprovideshigh-speedcircuitstoensuretheopeningofvariousservicesontheInternet.Forexample,servicessuchasmultimediaandvideoconferencing.

3.ChinaNethasachievednationwideuserroamingandhasbecomealeaderinthistechnicalfield.InordertofullyreflectthecharacteristicsofChinaNetasanationalpublicservicedatanetwork,andtoadapttotherequirementsofdial-upuserstoaccessthenetworkindifferentplaces,ChinaNetadoptsthetransparentroamingtechnologyofnationalnetworkusers,sothatChinaNetuserscanusenetworkresourcesthroughChinaNet'slocalnodesinanyprovince.

4.ChinaNetwillprovideuserswithafriendlyChineseinterface,whichisconvenientforuserstousevariousnetworkresources,especiallyforuserswhoarenewtotheInternet.

5.Richonlineinformation.SincetheopeningofChinaNet,variousinformationsourceshavebeenonline,andtherearemoreandmoreChineseinformation,suchasnews,tourism,economy,education,sports,etc.,userscancheckallkindsofinformationonlineatanytime.NowmanyusershaveinquiredaboutstockinformationthroughChinaNetandconductedonlinetransactions.

6.High-qualityservice.TheoperationandmaintenanceofChinaNetnetworkadoptsa24-hourworksystemtosolvenetworkproblemsatanytime.Atthesametime,ChinaNetalsoprovidesvarioustechnicalsupporttosolvevariousproblemsencounteredbyusersontheInternet.

Provideservices

1.E-mail

ChinaNetprovidesuserswithSMTP-compliante-mailservicesthroughMAILSERVER.Throughe-mail,youcancommunicatewithallusersontheInternet.UserscarryoutE-MAILcommunication;carryoutE-MALcommunicationwithusersonpublice-mailsystemsofvariouscountriesthathavebeenconnectedtotheInternet;querytheE-MAILinformationqueryserverequippedontheInternet;jointhroughthemailinglist(MAILINGLIST)Gotorelevantannouncements,discussions,debates,andgetinterestedinformation.

2.USENETNews

USENETisaworldwideelectronicbulletinboardforpublishingannouncements,newsandvariousarticlesforeveryonetouse.EachforumofUSENETiscalledanewsgroup.Justlikeanewspaper,everymanuscriptisregardedasanarticle.Everyonecanreadit,ornotreadarticlesthatarenotofinteresttoeveryone.Everyonewhohasreadthearticlecan.Commentoransweroraddnewcontentbasedonyourownopinions.

3.TelnetloginTELNET

Teleloginreferstotheprocessinwhichtheuser'scomputerbecomesaremotecomputerterminalthroughtheInternetwiththesupportofthenetworkcommunicationprotocol.Tologinonaremotecomputer,youmustfirstbecomealegaluserofthesystemandhaveacorrespondingaccountandpassword.Oncetheloginissuccessful,theusercanusealltheresourcesopenedtotheoutsideworldbytheremotecomputerinrealtime.

ManyforeignuniversitylibrariesprovideTELNETexternalonlinesearchservices.Somegovernmentsandresearchinstitutionsalsoopentheirdatabasestotheoutsideworld,providingvariousmenu-drivenuserinterfacesandevenfull-textsearchinterfacesforusersQuerythroughremotelogin.Whenperformingremotelogin,theusershouldfirstgivethecommunicationdomainnameorIPaddressoftheremotecomputerintheTELNETcommand,andthenaccepttheinquiryfromtheotherparty'ssystem,andtypeintheirusernameandpasswordcorrectly.Sometimes,youhavetoanswerthetypeofemulationterminalyouareusing.SomedatabasesontheINTERNETprovideopenremoteloginservices.Toquerythistypeofdatabase,youdonotneedtoobtainanaccountandpasswordfirst,butusepublicusersdisclosedbythesystem.

4.Filetransfer-FTP

ThefiletransferserviceallowsusersontheInternettotransferfilesfromonecomputertoanother.Filetransferissimilartoremotelogin,botharereal-timeonlineservices.Logintotheotherparty’scomputerwhenworking.Unlikeremotelogin,userscanonlyperformfilesearch-relatedoperationsafterloggingin,suchascoupworkingdirectory,listingfiledirectories,settingtransmissionparameters,andtransferringfiles.UsingFTPcantransferalmostalltypesoffiles:textfiles,Binaryexecutablefiles,imagefiles,soundfiles,datacompressionfiles,etc.INTERNETalsoprovidesan"anonymousfiletransferservice"(AnonymousFTP).Whenuserslogin,theycanuseAnonymousastheusernameandtheirownemailaddressasthepassword,andthentheycanlogintothesystemforfiletransfer.

5,GOPHER

GOPHERisamenu-driveninformationquerysoftware,whichorganizesonlineinformationintoanon-linemenusystemtofacilitateusers'browsingandinterestItcanautomaticallyconverttheuser’sinstructionsintoFTPorTELNETcommands.Undertheguidanceofthemenu,theusercanaccesstheremoteonlineinformationsystemontheINTERNETinrealtimewithoutknowingtheaddressofthemachineitisvisiting.

6,WWW(WorldWideWeb)

WWWis-ahypertext-basedinformationdetectiontool,whichprovidesafriendlyinformationqueryinterface,WWWItseamlesslyintegratesexistinginformationresources(suchasimages,text,soundandvideo)ontheInternet,andprovidesquicksearchinagraphicalinterfacemode.ThesamegraphicalinterfacecanalsobeusedtoconnectwithotherserversontheInternet.

7,Archie

ArchiecanautomaticallyandregularlyquerytheINTERNETFTPserver,andstorethefilesinitinasingle,searchabledatabase,whichisArchieTheindexofthefiledirectorydatainalltheserversthatcanbefound.Aslongastheusergivesthefiletypeandfilenamethathewantstofind,theArchieserverwillpointoutwhichFTPserverstoressuchfileson.ManyArcbieserversalsoacceptqueriesfromusers’e-mails.

8.WAIS(WideAreaInformationServer)

WAISiscalledthedatabaseofthedatabase,ageneralinterfacesoftwareforuserstoqueryvariousdatabasesdistributedontheInternet.AslongastheuserselectsthedesireddatabasewiththecursorinthedatabaselistandkeyinthequeryGuanJianyu,thesystemcanautomaticallyperformaremotequerytohelpreadoutalltherecordscontainingthequeryterminthecorrespondingdatabase,andaccordingtothequerykeywordinThefrequencyofoccurrenceineachrecordisscored,andthehighestscoreis1000points.Theusercanfurtherchoosewhethertoreadtherecordedcontentofinterest.

Networkaccessmethod

1.Dial-upaccess

(1)AccesstothenetworkthroughtheUNIXhostonChinaNet(TELNET)

Dial-upaccessfeeLess,suitableforsmallbusinessunitsorindividuals.Dial-upusersneedtomeetthefollowingconditions:aPC,communicationsoftware,aMODEMandatelephoneline,andapplyforanetworkaccountatthelocaltelecommunicationsbureautouseit.Foreachcommunication,firstlogintothehostonChinaNetviatelephonedial-up,runtheIPsoftware,andthenentertheInternetthroughthesoftwareprovidedbytheUNIXhost.E-mail,TELNET,GOPHERandFTPservicescanbeusedtoaccessthenetworkinthisway.

(2)AccesstothenetworkthroughSLIP/PPPprotocol

ThroughSLIP/PPP,thetelephonedial-upmethodachievesexactlythesamefunctionasthededicatedlineaccesstothenetwork(onlythecommunicationrateissubjecttocertainrestrictions).Thismethodissuitableforuserswhohaveasmallbusinessbutwanttoaccessthenetworkasahost.ThehardwarerequiredbyuserswhoaccessthenetworkthroughSLIP/PPPisexactlythesameasthatofordinarydial-upaccess,butthedifferenceisthattheyneedtobeequippedwithSLIP/PPPsoftware.ThroughSLIP/PPPaccesstothenetwork,userscanenjoyallservicesontheInternet.

2.Accessthenetworkthroughthepacketnetwork

(1)AccessthenetworkthroughtheUNIXhostonChinaNet

Thismethodissuitableforallusersonthepacketnetwork.TheuseronlyneedstoapplyforanINTERNETaccountandgothroughtherelevantprocedurestochangefromagroupusertoanINTERNETuser.TheINTERNETservicethatuserswhoaccessthenetworkinthiswaycanuseisexactlythesameasthatofordinarydial-inusers,butthecommunicationcosthasnothingtodowiththecommunicationdistance.

(2)AccesstothenetworkviaTCP/IPprotocolthroughthepacketnetwork

Thismethodissimilartothededicatedlineaccesstothenetwork,exceptthatthetransmissionmediumisthevirtualcircuit(SVCorPVC)ofthepacketnetwork,Notaphysicalcircuit.Inadditiontotheauthorizedusersofthepacketnetwork,theuseralsoneedstobeequippedwitharoutersupportingtheTCP/IPprotocolandahostornetworkrunningIPsoftware.Atthesametime,usersalsoneedtoapplyforIPaddressesanddomainnamesfortheironlinedevices.Inthisway,allterminalsontheusernetworkcanbeINTERNETusersandcanenjoyallINTERNETservices.

Throughthepacketnetworkandrouteraccesstothenetwork,userscanuseonemachineformultiplepurposes,thatis,userscancommunicatewithusersonthepacketnetworkatthesametimeinadditiontotheauthorizedusersoftheInternet.Accesstothenetworkthroughthepacketnetwork,thenetworkaccessratecanbe1200~64000bpsoptional.Thismethodissuitableforuserswhousee-mailsandotheruserswhodonothavetoomuchcommunication.

3.Accesstothenetworkthroughframerelay

ThecharacteristicsofframerelayarehighcommunicationefficiencyandtheabilitytoestablishPVCswithmultiplepointsatthesametime,andtherentalfeeislowerthanthatofdedicatedlines(fordedicatedlines).20%),suitableforinterconnectionbetweenLANs.Toaccessthenetworkthroughframerelay,usersneedtoapplyfortheframerelaycircuitusedwhenaccessingthenetwork,beequippedwitharouterthatsupportstheTCP/IPprotocol,andapplyforIPaddressesanddomainnamesforonlinedevices.Byaccessingthenetworkthroughframerelay,theterminalsontheusernetworkcanenjoyalltheservicesoftheInternet.Theframerelaynetworkaccessrateisoptionalfrom9600bps-2048kbps,whichissuitableforalluserswhorequirehostornetworkaccess.

4.Accesstothenetworkthroughadedicatedline

Thededicatedlineaccesstothenetworkhasahighcommunicationrate,whichissuitablefornetworkuserswithlargebusinessvolume,butthenetworkaccesscostishigh,andtheuserneedstohaveadedicatedlineandarouter.Afterenteringthenetwork,allterminalsandworkstationsontheInternetcanenjoyallINTERNETservices.Thecommunicationrateofthededicatedlinenetworkis1200bps~2048kbpsoptional.

Accessmethods

InordertousetheresourcesontheInternet,usershavethreebasicaccessmethods,namelydial-up,dedicatedlineandquasi-dedicatedline.

1.Dialingmethod

ThetelephonedialingmethodisasimpleInternetaccessmethod.Itconnectstheuser'scomputerandmodemtotheINTERNEThostthroughatelephonelinedial-up.Theuser'scomputercanbeaPC,Macintosh,orAmiga.Oncetheconnectioniscompleted,theremotecommunicationsoftwarewillemulatethiscomputerintoaterminal,sothattheusercancommunicatewiththehostcomputerontheInternet.Thedial-upmethodismoreeconomicalandcanmeettheneedsofmostusers.Theuser'shardwareequipmentconfigurationissimple,justregisteranaccountinthe"host"attheendofthelNTERNETserviceprovider,andtheuser'scomputercaneasilyenterthehosttoobtainvariousnetworkprogramsontheInternet.Dial-upconnectioncanusuallyprovideEmail,Telnet,GophetandFTPservices.ButwhendoingFTP,youneedtodosomething.Thedownloadworkfromthehost"tothepersonalcomputer.

2.Dedicatedline

Theuser’slocalareanetworkorhostisdirectlyconnectedtothelocalInternetserviceprovider’snetworkwithacable,andtheuserhashisownHostnameandaddress.Thiskindofconnectionisgenerallysuitableforsomelargecompanies,scientificresearchinstitutionsandotherunits.Itisacomplicatedandexpensivesolution.Whenconnecting,theuserandtheInternetserviceproviderneedtoassembleandruntheIPSoftwarerouter.Theuser’slocalareanetworkprovidesacompleteInternetconnectionforallpersonalcomputersandworkstationsonthelocalareanetworkthroughthisrouter.Theconnectionrateofthededicatedlinemethodishigher,andtheusercanusethecomputerorworkstationtodirectlyconnecttotheInternettoobtainvariousnetworkprogramsForexample,theusercanruntheuser-friendlyguidancesoftwareandthegraphicalwwwsearch,etc.

3,thequasi-dedicatedlinemethod

Thequasi-dedicatedlinemethodstillusesthetelephonelineandmodemtoconnecttoitthroughdial-upOntheInternet.Thedifferenceisthattheuser’scomputerisnotusedasaterminal.BothitandthehostuseaspecialcomputerprogramSLIP(ConnectingInternetProtocol)orPPP(Point-to-PointProtocol).Theuser’smachinecanbeconsideredasphysicalInternetPartofit,andhasitsownhostnameandaddress.ThismethodisalsocalledSLIP/PPP.ThismethodismoresuitableforuserswhodonothaveadedicatedlineandwanttoobtainallthenetworkfunctionsandadvantagesoftheInternet.Thisisamoreeconomicalsolution.Thismethodissuitableforsmallcompaniesandfamilies.Itshardwareconfigurationisthesameasthedialingmethod,butitneedstouseSLIP/PPPsoftwaretomakethestandardtelephonelinepresentthecharacteristicsofadedicatedline.Thismethodallowsuserstoobtainvariousnetworkfunctions,suchaswwwGraphicalretrieval.Inaddition,whendoingFTP,thefilecanbedownloadeddirectlytotheuser’spersonalcomputer.