ch1_computer network and the internet(2)new

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1、Chapter1ComputerNetworksandtheInternetComputerNetworking:ATopDownApproach,4thedition.JimKurose,KeithRossAddison-Wesley,July2007.Introduction1-1Chapter1:IntroductionOurgoal:Overview:get“feel”andwhat’stheInternet?terminology(术语)what’saprotocol（协议）?moredepth,detailnetworkedge;hosts,accesslat

2、erincoursenet（访问网络）,physicalmedia（approach:物理介质）useInternetasnetworkcore:packet（分组）example/circuit（电路）switching,Internetstructureperformance:loss,delay,throughput（吞吐量）securityprotocollayers,servicemodelshistoryIntroduction1-2What’stheInternetPCmillionsofconnectedMobilenetworkservercomp

3、utingdevices:hostsGlobalISP=endsystems（端系统）wirelesslaptoprunningnetworkappscellularhandheld（网络应用）HomenetworkRegionalISPcommunicationlinksaccessfiber,copper,pointsradio,satelliteInstitutionalnetworkwiredlinkstransmissionrate=bandwidth（带宽）routers:forwardrouterpackets(分组，chunksofdata)Introdu

4、ction1-4What’stheInternet:Mobilenetworkprotocolscontrolsending,receivingofmsgsGlobalISPe.g.,TCP,IP,HTTP,Skype,EthernetHomenetworkInternet:“networkofnetworks”RegionalISPlooselyhierarchicalpublicInternetversusInstitutionalnetworkprivateintranetInternetstandardsRFC:RequestforcommentsIETF:

5、InternetEngineeringTaskForceIntroduction1-5Internetservice：communicationinfrastructure（基础设施）enablesdistributedapplications:Web,VoIP,email,games,e-commerce（电子商务）,filesharingcommunicationservicesprovidedtoapps:reliabledatadeliveryfromsourcetodestination“besteffort”(unreliable)datadeliveryIn

6、troduction1-6What’saprotocol（协议）?humanprotocols:networkprotocols:“what’sthetime?”machinesratherthan“Ihaveaquestion”humansintroductionsallcommunicationactivityinInternetgovernedbyprotocols…specificmsgssent…specificactionstakenprotocolsdefineformat,whenmsgsreceived,orderofmsgssentandorother

7、eventsreceivedamongnetworkentities,andactionstakenonmsgtransmission,receiptIntroduction1-7What’saprotocol?ahumanprotocolandacomputernetworkprotocol:HiTCPconnectionrequestHiTCPconnectionGottheresponsetime?Gethttp://www.awl.com/kurose-ros