計算機專業(yè)英語（第3版）-練習及情境對話 課件 3 Reading Material（閱讀材料）

閱讀材料ReadingMaterial計算機專業(yè)英語chapterthree

FoundationofComputerNetworkMissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?1．ChinaIPv6NetworktoUseJuniperTechnology計算機專業(yè)英語TheChinaNextGenerationInternetproject,formedtopromoteIPv6throughoutChina,willbeusingJuniperNetworks’(JNPR)M-andT-seriesroutingplatforms.JuniperNetworksplatformswillbedeployedintheChinaNextGenerationInternet’s(CNGI)participatingnetworks,includingtheChinaEducationandResearchNetwork(CERNET2),ChinaMobile,ChinaNetcom,ChinaRailcom,ChinaTelecomandChinaUnicom.TheCNGIprojectwaslaunchedin2003byChina’sNationalDevelopmentandReformCommission(NDRC),anditscharteristocreateanext-generationnationalIPv6backbonecovering20citiesand39massivenetworkpointsofpresence(GigaPOPs)toprovidepervasiveadvancedIPservices.MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?1．ChinaIPv6NetworktoUseJuniperTechnology計算機專業(yè)英語IPv6isthenextgenerationInternetProtocol,andimprovesonthecurrentversionbygreatlymultiplyingthenumberofIPaddressestoaccommodatethegrowingnumberofnetworkeddevices,usersandapplicationswithbuilt-insecuritymechanisms.Oncedeployed,theJuniperNetworksplatformswillprovideatestbedforMultiprotocolLabelSwitching(MPLS)andenabletheserviceproviderstoofferawidevarietyofadvancedIPv6-basedservicesinthenearfuture.MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?1．ChinaIPv6NetworktoUseJuniperTechnology計算機專業(yè)英語TheseservicesincludeVirtualPrivateNetworking(VPN),high-qualityIPvoiceandvideostreaming,aswellasthird-generation(3G)mobileapplications.TheM-andT-seriesplatformswillalsoprovideinteroperabilitywithnetworksbasedonthecurrentversionInternetProtocol,IPv4,byusingadvancedIPv4-to-IPv6interworkingfeaturessupportedbytheindustry-leadingJUNOSoperatingsystem.Oncedeployed,theJuniperNetworksplatformswillprovideatestbedforMultiprotocolLabelSwitching(MPLS)andenabletheserviceproviderstoofferawidevarietyofadvancedIPv6-basedservicesinthenearfuture.MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?2．Intranet計算機專業(yè)英語Withtheadvancementmadeinbrowser-basedsoftwarefortheInternet,manyprivateorganizationsareimplementingintranets.AnintranetisaprivatenetworkutilizingInternet-typetools,butavailableonlywithinthatorganization.Forlargeorganizations,anintranetprovidesaneasyaccessmodetocorporateinformationforemployees.EthernetisthemostpopularphysicallayerLANtechnologyinusetoday.OtherLANtypesincludeTokenRing,FastEthernet,FiberDistributedDataInterface(FDDI),AsynchronousTransferMode(ATM)andLocalTalk.Ethernetispopularbecauseitstrikesagoodbalancebetweenspeed,cost,andeaseofinstallation.Thesebenefits,combinedwithwideacceptanceinthecomputermarketplaceandtheabilitytosupportvirtuallyallpopularnetworkprotocols,make3．EthernetMissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?3．Ethernet計算機專業(yè)英語Ethernetanidealnetworkingtechnologyformostcomputeruserstoday.TheInstituteforElectricalandElectronicEngineers(IEEE)definestheEthernetstandardasIEEEStandard802.3.ThisstandarddefinesrulesforconfiguringanEthernetnetworkaswellasspecifyinghowelementsinanEthernetnetworkinteractwithoneanother.ByadheringtotheIEEEstandard,networkequipmentandnetworkprotocolscancommunicateefficiently.ForEthernetnetworksthatneedhighertransmissionspeeds,theFastEthernetstandard(IEEE802.3u)hasbeenestablished.ThisstandardraisestheEthernetspeedlimitfrom10Megabitspersecond(Mbps)to100Mbpswithonlyminimalchangestotheexistingcablestructure.TherearethreetypesofFastEthernet:100BASE-TXforusewithlevel5UTPcable,100BASE-FXforusewithfiber-opticcable,and100BASE-T4whichutilizesanextratwowiresforusewithlevel3UTPcable.4．FastEthernetMissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?4．FastEthernet計算機專業(yè)英語The100BASE-TXstandardhasbecomethemostpopularoneduetoitsclosecompatibilitywiththe10BASE-TEthernetstandard.Forthenetworkmanager,theincorporationofFastEthernetintoanexistingconfigurationpresentsahostofdecisions.Managersmustdeterminethenumberofusersineachsiteonthenetworkthatneedthehigherthroughput,decidewhichsegmentsofthebackboneneedtobereconfiguredspecificallyfor100BASE-Tandthenchoosethenecessaryhardwaretoconnectthe100BASE-Tsegmentswithexisting10BASE-Tsegments.GigabitEthernetisafuturetechnologythatpromisesamigrationpathbeyondFastEthernetsothenextgenerationofnetworkswillsupportevenhigherdatatransferspeeds.MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?5．TokenRing計算機專業(yè)英語TokenRingisanotherformofnetworkconfigurationwhichdiffersfromEthernetinthatallmessagesaretransferredinaunidirectionalmanneralongtheringatalltimes.Dataistransmittedintokens,whicharepassedalongtheringandviewedbyeachdevice.Whenadeviceseesamessageaddressedtoit,thatdevicecopiesthemessageandthenmarksthatmessageasbeingread.Asthemessagemakesitswayalongthering,iteventuallygetsbacktothesenderwhonownotesthatthemessagewasreceivedbytheintendeddevice.Thesendercanthenremovethemessageandfreethattokenforusebyothers.VariousPCvendorshavebeenproponentsofTokenRingnetworksatdifferenttimesandthusthesetypesofnetworkshavebeenimplementedinmanyorganizations.MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?6．Protocols計算機專業(yè)英語Networkprotocolsarestandardsthatallowcomputerstocommunicate.Aprotocoldefineshowcomputersidentifyoneanotheronanetwork,theformthatthedatashouldtakeintransit,andhowthisinformationisprocessedonceitreachesitsfinaldestination.Protocolsalsodefineproceduresforhandlinglostordamagedtransmissionsor“packets.”TCP/IP(forUNIX,WindowsNT,Windows95andotherplatforms),IPX(forNovellNetWare),DECnet(fornetworkingDigitalEquipmentCorp.computers),AppleTalk(forMacintoshcomputers),andNetBIOS/NetBEUI(forLANManagerandWindowsNTnetworks)arethemaintypesofnetworkprotocolsinusetoday.MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacomputer,butIknowlittleaboutit.Li:Doyoulikeabrandmachineoracompatiblemachine?6．Protocols計算機專業(yè)英語Althougheachnetworkprotocolisdifferent,theyallsharethesamephysicalcabling.Thiscommonmethodofaccessingthephysicalnetworkallowsmultipleprotocolstopeacefullycoexistoverthenetworkmedia,andallowsthebuilderofanetworktousecommonhardwareforavarietyofprotocols.Thisconceptisknownas“protocolindependence,”whichmeansthatdevicesthatarecompatibleatthephysicalanddatalinklayersallowtheusertorunmanydifferentprotocolsoverthesamemedium.MissLi:AsalesgirlinComputerTownMr.Zhang:AcomputerconsumerwhoknowslittleaboutcomputerLi:CanIhelpyou,Sir?Zhang:Yes.I’dliketobuyacompu