chapter 1 computer networks and the internet

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1、CSB051–ComputerNetworks電腦網路Chapter1ComputerNetworksandtheInternet吳俊興國立高雄大學資訊工程學系Spring2006Outline1.1WhatistheInternet?1.2Networkedge1.3Networkcore1.4Accessnetworksandphysicalmedia1.5ISPsandInternetbackbones1.6Delay&lossinpacket-switchednetworks1.7Protocollayersandtheirservicemodels1.

2、8HistoryIntroduction1-2What’stheInternet:“nutsandbolts”viewAworldwidenetworkthatrouterworkstationinterconnectsmillionsofcomputingdevicesservermobileßmillionsofconnectedlocalISPcomputingdevices:hosts=endsystemsßrunningnetworkappsregionalISPßcommunicationlinksmfiber,copper,radio,satell

3、itemtransmissionrate=bandwidthßrouters:forwardpackets(chunksofdata)companynetworkIntroduction1-3What’stheInternet:“nutsandbolts”viewßprotocolscontrolsending,routerworkstationreceivingofmsgsserverme.g.,TCP,IP,HTTP,FTP,PPPmobilemIP:InternetProtocollocalISPmTCP:TransmissionControlProtoc

4、olßInternet:“networkofregionalISPnetworks”mlooselyhierarchicalmpublicInternetversusprivateintranetßInternetstandardscompanymRFC:RequestforcommentsnetworkmIETF:InternetEngineeringTaskForceIntroduction1-4What’stheInternet:aserviceviewßcommunicationinfrastructureenablesdistributedapplic

5、ations:mWeb,email,games,e-commerce,filesharingßcommunicationservicesprovidedtoapps:mConnectionlessunreliablemconnection-orientedreliableIntroduction1-5What’saprotocol?humanprotocols:networkprotocols:ß“what’sthetime?”ßmachinesratherthanß“Ihaveaquestion”humansßintroductionsßallcommunic

6、ationactivityinInternetgovernedbyprotocols…specificmsgssent…specificactionstakenprotocolsdefineformat,whenmsgsreceived,orderofmsgssentandorothereventsreceivedamongnetworkentities,andactionstakenonmsgtransmission,receiptIntroduction1-6What’saprotocol?ahumanprotocolandacomputernetworkp

7、rotocol:HiTCPconnectionreqHiTCPconnectionGottheresponsetime?Gethttp://www.awl.com/kurose-ross2:00timeQ:Otherhumanprotocols?Introduction1-7RFC(RequestforComments)ßIETFmhttp://www.rfc-editor.org/rfc-index2.htmlmhttp://www.rfc-editor.org/rfcxx00.htmlßRFC791:IP(InternetProtocol)ßRF

8、C793:TCP(Tra