Internet基本概念What’stheInternet:“nutsandbolts”viewmillionsofconnectedcomputingdevices:hosts=endsystemsrunning

network

appscommunicationlinksfiber,copper,radio,satellitetransmissionrate=bandwidthPacket

switches:

forwardpackets(chunksofdata)routersandswitcheswiredlinkswirelesslinksroutersmartphonePCserverwirelesslaptop“Fun”internetappliancesIPpictureframe/Web-enabledtoaster+weatherforecasterInternetphonesInternetrefrigeratorSlingbox:watch,controlcableTVremotelyTweet-a-watt:monitorenergyuseWhat’stheInternet:“nutsandbolts”viewprotocolscontrolsending,receivingofmsgse.g.,TCP,IP,HTTP,Skype,802.11InternetstandardsRFC:RequestforcommentsIETF:InternetEngineeringTaskForceWhat’stheInternet:“nutsandbolts”viewmobilenetworkglobalISPregionalISPhomenetworkinstitutionalnetworkInternet:“networkofnetworks”InterconnectedISPsWhat’stheInternet:aserviceviewInfrastructurethatprovidesservicestoapplications:Web,VoIP,email,games,e-commerce,socialnets,…providesprogramminginterfacetoapps:hooksthatallowsendingandreceivingappprogramsto“connect”toInternetprovidesserviceoptions,analogoustopostalservicemobilenetworkglobalISPregionalISPhomenetworkinstitutionalnetworkThetopologystructureStarTreeBusMeshRingNetworkNode+communicationlines,reflectingthenetworkstructureoftheinter-entityrelationsWhat’saprotocol?networkprotocolshuman

protocols“what’sthetime?”“Ihaveaquestion”introductionsmachinesratherthanhumansallcommunicationactivityinInternetgovernedbyprotocolsprotocolsdefineformat,orderofmsgssentandreceivedamongnetworkentities,andactionstakenonmsgtransmission,receipt…specificmsgssent…specificactionstakenwhenmsgsreceived,orothereventsHiHiGotthetime?2:00TCPconnectionrequestTCPconnectionresponseGet/kurose-ross<file>timeahumanprotocolandacomputernetworkprotocol:Q:Otherhumanprotocols?What’saprotocol?關于網絡協議的說明這些規則明確規定了所交換的數據的格式以及有關的同步問題（同步含有時序的意思）。網絡協議(networkprotocol)，簡稱為協議，是為進行網絡中的數據交換而建立的規則、標準或約定。計算機網絡中的數據交換必須遵守事先約定好的規則。網絡協議的組成要素語義需要發出何種控制信息，完成何種動作

以及做出何種響應。同步

事件實現順序的詳細說明。語法數據與控制信息的結構或格式。

Acloserlookatnetworkstructurenetworkedge:hosts:clientsandserversserversoftenindatacentersaccessnetworks,physicalmedia:wired,wirelesscommunication