CCNA-12-网络的功能和网络拓扑结构课件

BuildingaSimpleNetworkExploringtheFunctionsofNetworkingBuildingaSimpleNetworkExploWhatIsaNetwork?WhatIsaNetwork?CommonPhysicalComponentsofaNetworkCommonPhysicalComponentsofInterpretingaNetworkDiagramInterpretingaNetworkDiagramResource-SharingFunctionsandBenefitsDataandapplicationsResourcesNetworkstorageBackupdevicesResource-SharingFunctionsandNetworkUserApplicationsE-mail(Outlook,POP3,Yahoo,andsoon)Webbrowser(IE,Firefox,andsoon)Instantmessaging(YahooIM,MicrosoftMessenger,andsoon)Collaboration(Whiteboard,Netmeeting,WebEx,andsoon)Databases(fileservers)NetworkUserApplicationsE-maiImpactofUserApplicationsontheNetworkBatchapplicationsFTP,TFTP,inventoryupdatesNodirecthumaninteractionBandwidthimportant,butnotcriticalInteractiveapplicationsInventoryinquiries,databaseupdates.Human-to-machineinteraction.Becauseahumaniswaitingforaresponse,responsetimeisimportantbutnotcritical,unlessthewaitbecomesexcessive.Real-timeapplicationsVoIP,videoHuman-to-humaninteractionEnd-to-endlatencycriticalImpactofUserApplicationsonCharacteristicsofaNetworkSpeedCostSecurityAvailabilityScalabilityReliabilityTopologyCharacteristicsofaNetworkSpPhysicalTopologyCategoriesPhysicalTopologyCategoriesLogicalTopologiesLogicalTopologiesBusTopologyAlldevicesreceivethesignal.BusTopologyAlldevicesreceivStarTopologyTransmissionthroughacentralpoint.Singlepointoffailure.StarTopologyTransmissionthroExtended-StarTopologyMoreresilientthanstartopology.Extended-StarTopologyMoreresRingTopologySignalstravelaroundring.Singlepointoffailure.RingTopologySignalstravelarDual-RingTopologySignalstravelinoppositedirections.Moreresilientthansinglering.Dual-RingTopologySignalstravFull-MeshTopologyHighlyfault-tolerantExpensivetoimplementFull-MeshTopologyHighlyfaultPartial-MeshTopologyTrade-offbetweenfaulttoleranceandcostPartial-MeshTopologyTrade-offConnectiontotheInternetConnectiontotheInternetSummaryAnetworkisaconnectedcollectionofdevicesthatcancommunicatewitheachother.Networkscarrydatainmanykindsofenvironments,includinghomes,smallbusinesses,andlargeenterprises.Therearefourmajorcategoriesofphysicalcomponentsinacomputernetwork:thecomputer,interconnections,switches,androuters.Networksaredepictedgraphicallyusingasetofstandardicons.Themajorresourcesthataresharedinacomputernetworkincludedataandapplications,peripherals,storagedevices,andbackupdevices.Themostcommonnetworkuserapplicationsincludee-mail,webbrowsers,instantmessaging,collaboration,anddatabases.Userapplicationsaffectthenetworkbyconsumingnetworkresources.SummaryAnetworkisaconnecteThewaysinwhichnetworkscanbedescribedincludecharacteristicsthataddressnetworkperformanceandstructure:

speed,

cost,

security,

availability,

scalability,

reliability,and

topology.

Aphysicaltopologydescribesthelayoutforwiringthephysicaldevices,whilealogicaltopologydescribeshowinformationflowsthroughanetwork.Inaphysicalbustopology,asinglecableeffectivelyconnectsallthedevices.Inaphysicalstartopology,eachdeviceinthenetworkisconnectedtothecentraldevicewithitsowncable.Whenastarnetworkisexpandedtoincludeadditionalnetworkingdevicesthatareconnectedtothemainnetworkingdevice,itiscalledanextended-startopology.Summary(Cont.)ThewaysinwhichnetworkscanSummary(Cont.)Inaringtopology,allthehostsareconnectedintheformofaringorcircle.Inadual-ringtopology,therearetworingstoprovideredundancyinthenetwork.Afull-meshtopologyconnectsalldevicestoeachother;inapartial-meshtopology,atleastonedevicehasmultipleconnectionstoallotherdevices.TherearethreecommonmethodsofconnectingthesmallofficetotheInternet:DSLusingtheexistingtelephonelines,cableusingtheCATVinfrastructure,andseriallinksusingtheclassicdigitallocalloops.Summary(Cont.)InaringtopolCCNA-12-网络的功能和网络拓扑结构课件BuildingaSimpleNetworkExploringtheFunctionsofNetworkingBuildingaSimpleNetworkExploWhatIsaNetwork?WhatIsaNetwork?CommonPhysicalComponentsofaNetworkCommonPhysicalComponentsofInterpretingaNetworkDiagramInterpretingaNetworkDiagramResource-SharingFunctionsandBenefitsDataandapplicationsResourcesNetworkstorageBackupdevicesResource-SharingFunctionsandNetworkUserApplicationsE-mail(Outlook,POP3,Yahoo,andsoon)Webbrowser(IE,Firefox,andsoon)Instantmessaging(YahooIM,MicrosoftMessenger,andsoon)Collaboration(Whiteboard,Netmeeting,WebEx,andsoon)Databases(fileservers)NetworkUserApplicationsE-maiImpactofUserApplicationsontheNetworkBatchapplicationsFTP,TFTP,inventoryupdatesNodirecthumaninteractionBandwidthimportant,butnotcriticalInteractiveapplicationsInventoryinquiries,databaseupdates.Human-to-machineinteraction.Becauseahumaniswaitingforaresponse,responsetimeisimportantbutnotcritical,unlessthewaitbecomesexcessive.Real-timeapplicationsVoIP,videoHuman-to-humaninteractionEnd-to-endlatencycriticalImpactofUserApplicationsonCharacteristicsofaNetworkSpeedCostSecurityAvailabilityScalabilityReliabilityTopologyCharacteristicsofaNetworkSpPhysicalTopologyCategoriesPhysicalTopologyCategoriesLogicalTopologiesLogicalTopologiesBusTopologyAlldevicesreceivethesignal.BusTopologyAlldevicesreceivStarTopologyTransmissionthroughacentralpoint.Singlepointoffailure.StarTopologyTransmissionthroExtended-StarTopologyMoreresilientthanstartopology.Extended-StarTopologyMoreresRingTopologySignalstravelaroundring.Singlepointoffailure.RingTopologySignalstravelarDual-RingTopologySignalstravelinoppositedirections.Moreresilientthansinglering.Dual-RingTopologySignalstravFull-MeshTopologyHighlyfault-tolerantExpensivetoimplementFull-MeshTopologyHighlyfaultPartial-MeshTopologyTrade-offbetweenfaulttoleranceandcostPartial-MeshTopologyTrade-offConnectiontotheInternetConnectiontotheInternetSummaryAnetworkisaconnectedcollectionofdevicesthatcancommunicatewitheachother.Networkscarrydatainmanykindsofenvironments,includinghomes,smallbusinesses,andlargeenterprises.Therearefourmajorcategoriesofphysicalcomponentsinacomputernetwork:thecomputer,interconnections,switches,androuters.Networksaredepictedgraphicallyusingasetofstandardicons.Themajorresourcesthataresharedinacomputernetworkincludedataandapplications,peripherals,storagedevices,andbackupdevices.Themostcommonnetworkuserapplicationsincludee-mail,webbrowsers,instantmessaging,collaboration,anddatabases.Userapplicationsaffectthenetworkbyconsumingnetworkresources.SummaryAnetworkisaconnecteThewaysinwhichnetworkscanbedescribedincludecharacteristicsthataddressnetworkperformanceandstructure:

speed,

cost,

security,

availability,

scalability,

reliability,and

topology.

Aphysicaltopologydescribesthelayoutforwiringthephysicaldevices,whilealogicaltopologydescribeshowinformationflowsthroughanetwork.Inaphysicalbustopology,asinglecableeffectivelyconnectsallthedevices.Inaphysicalstartopology,eachdeviceinthenetworkisconnected