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1、BuildingaSimpleNetworkExploringtheFunctionsofNetworkingWhatIsaNetwork?CommonPhysicalComponentsofaNetworkInterpretingaNetworkDiagramResource-SharingFunctionsandBenefitsDataandapplicationsResourcesNetworkstorageBackupdevicesNetworkUserApplicationsE-mail(O
2、utlook,POP3,Yahoo,andsoon)Webbrowser(IE,Firefox,andsoon)Instantmessaging(YahooIM,MicrosoftMessenger,andsoon)Collaboration(Whiteboard,Netmeeting,WebEx,andsoon)Databases(fileservers)ImpactofUserApplicationsontheNetworkBatchapplicationsFTP,TFTP,inventoryup
3、datesNodirecthumaninteractionBandwidthimportant,butnotcriticalInteractiveapplicationsInventoryinquiries,databaseupdates.Human-to-machineinteraction.Becauseahumaniswaitingforaresponse,responsetimeisimportantbutnotcritical,unlessthewaitbecomesexcessive.Re
4、al-timeapplicationsVoIP,videoHuman-to-humaninteractionEnd-to-endlatencycriticalCharacteristicsofaNetworkSpeedCostSecurityAvailabilityScalabilityReliabilityTopologyPhysicalTopologyCategoriesLogicalTopologiesBusTopologyAlldevicesreceivethesignal.StarTopol
5、ogyTransmissionthroughacentralpoint.Singlepointoffailure.Extended-StarTopologyMoreresilientthanstartopology.RingTopologySignalstravelaroundring.Singlepointoffailure.Dual-RingTopologySignalstravelinoppositedirections.Moreresilientthansinglering.Full-Mesh
6、TopologyHighlyfault-tolerantExpensivetoimplementPartial-MeshTopologyTrade-offbetweenfaulttoleranceandcostConnectiontotheInternetSummaryAnetworkisaconnectedcollectionofdevicesthatcancommunicatewitheachother.Networkscarrydatainmanykindsofenvironments,incl
7、udinghomes,smallbusinesses,andlargeenterprises.Therearefourmajorcategoriesofphysicalcomponentsinacomputernetwork:thecomputer,interconnections,switches,androuters.Networksaredepictedgraphicallyusingasetofstandardicons.Themajorresourcesthataresharedinacom
8、puternetworkincludedataandapplications,peripherals,storagedevices,andbackupdevices.Themostcommonnetworkuserapplicationsincludee-mail,webbrowsers,instantmessaging,collaboration,anddatabases.Userapplicationsaffectthenetworkbyconsum
