《计算机网络 Computer Networking》课程PPT教学课件（A Top Down Approach，7th edition）Chapter 1 Computer Networks and the Internet

Computer Chapter l Networking A TOP-DOWN APPROACH REVENTH EDITION Introduction KUROSE·ROSS A note on the use of these Powerpoint slides: We're making these slides freely available to all (faculty,students,readers). Theyre in PowerPoint form so you see the animations:and can add,modify, and delete slides (including this one)and slide content to suit your needs. They obviously represent a /ot of work on our part In return for use,we only ask the following: Computer If you use these slides (e.g in a class)that you mention their source (after all,we'd like people to use our book!) Networking:A Top If you post any slides on a www site,that you note that they are adapted from(or perhaps identical to)our slides,and note our copyright of this Down Approach material Thanks and enjoy!JFK/KWR 7th edition Jim Kurose,Keith Ross CAll material copyright 1996-2016 J.F Kurose and K.W.Ross,All Rights Reserved Pearson/Addison Wesley April 2016 Introduction1-1

Introduction1-1 Chapter 1 Introduction Computer Networking: A Top Down Approach A note on the use of these Powerpoint slides: We’re making these slides freely available to all (faculty, students, readers). They’re in PowerPoint form so you see the animations; and can add, modify, and delete slides (including this one) and slide content to suit your needs. They obviously represent a lot of work on our part. In return for use, we only ask the following: ▪ If you use these slides (e.g., in a class) that you mention their source (after all, we’d like people to use our book!) ▪ If you post any slides on a www site, that you note that they are adapted from (or perhaps identical to) our slides, and note our copyright of this material. Thanks and enjoy! JFK/KWR All material copyright 1996-2016 J.F Kurose and K.W. Ross, All Rights Reserved 7 th edition Jim Kurose, Keith Ross Pearson/Addison Wesley April 2016

Chapter introduction our goal: overview: ■get“feel”and ■what's the Internet? terminology what's a protocol? ■more depth,detail network edge;hosts,access net, physical media later in course network core:packet/circuit ■approach: switching,Internet structure ·use Internet as performance:loss,delay, example throughput security protocol layers,service models ■history Introduction1-2

Introduction Chapter 1: introduction our goal: ▪ get “feel” and terminology ▪ more depth, detail later in course ▪ approach: • use Internet as example overview: ▪ what’s the Internet? ▪ what’s a protocol? ▪ network edge; hosts, access net, physical media ▪ network core: packet/circuit switching, Internet structure ▪ performance: loss, delay, throughput ▪ security ▪ protocol layers, service models ▪ history 1-2

Chapter I:roadmap 1.I what is the Internet? 1.2 network edge end systems,access networks,links 1.3 network core packet switching,circuit switching,network structure 1.4 delay,loss,throughput in networks 1.5 protocol layers,service models 1.6 networks under attack:security 1.7 history Introduction1-3

Introduction Chapter 1: roadmap 1.1 what is the Internet? 1.2 network edge ▪ end systems, access networks, links 1.3 network core ▪ packet switching, circuit switching, network structure 1.4 delay, loss, throughput in networks 1.5 protocol layers, service models 1.6 networks under attack: security 1.7 history 1-3

What's the Internet:“nuts and bolts'”view PC ■billions of connected mobile network 目 server computing devices: wireless ·hosts=end systems global ISP aptop smartphone ·running network apps home communication links network regional ISP wreless fiber,copper,radio, links satellite wred links ·transmission rate: bandwidth packet switches:forward router packets(chunks of data) institutional 。routers and switches network Introduction1-4

Introduction What’s the Internet: “nuts and bolts” view ▪ billions of connected computing devices: • hosts = end systems • running network apps ▪ communication links • fiber, copper, radio, satellite • transmission rate: bandwidth ▪ packet switches: forward packets (chunks of data) • routers and switches wired links wireless links router smartphone PC server wireless laptop 1-4 mobile network global ISP regional ISP home network institutional network

“Fun”Internet-.connected devices Web-enabled toaster weather forecaster IP picture frame http://www.ceiva.com/ Tweet-a-watt: Slingbox:watch, monitor energy use control cable TV remotely sensorized, bed mattress Internet refrigerator Internet phones Introduction1-5

Introduction “Fun” Internet-connected devices IP picture frame http://www.ceiva.com/ Web-enabled toaster + weather forecaster Internet phones Internet refrigerator Slingbox: watch, control cable TV remotely 1-5 Tweet-a-watt: monitor energy use sensorized, bed mattress

What's the Internet:"nuts and bolts"view ■Internet:“network of networks” mobile network ·Interconnected ISPs global ISP protocols control sending,receiving of messages e.g.,TCP,IP,HTTP,Skype,802.1I home network ■Internet standards regional ISP RFC:Request for comments IETF:Internet Engineering Task Force institutional network Introduction 1-6

Introduction ▪ Internet: “network of networks” • Interconnected ISPs ▪ protocols control sending, receiving of messages • e.g., TCP, IP, HTTP, Skype, 802.11 ▪ Internet standards • RFC: Request for comments • IETF: Internet Engineering Task Force What’s the Internet: “nuts and bolts” view 1-6 mobile network global ISP regional ISP home network institutional network

What's the Internet:a service view mobile network infrastructure that provides services to applications: global ISP Web,VolP,email,games,e- commerce,social nets,... home provides programming etwork regional ISP interface to apps hooks that allow sending and receiving app programs to"connect"to Internet provides service options, analogous to postal service institutional network Introduction 1-7

What’s the Internet: a service view ▪ infrastructure that provides services to applications: • Web, VoIP, email, games, e￾commerce, social nets, … ▪ provides programming interface to apps • hooks that allow sending and receiving app programs to “ connect ” to Internet • provides service options, analogous to postal service Introduction 1-7 mobile network global ISP regional ISP home network institutional network

What's a protocol? human protocols: network protocols: “what's the time?” machines rather than ·“I have a question” humans ■introductions all communication activity in Internet governed by ..specific messages sent protocols ..specific actions taken when messages protocols define format,order of received,or other events messages sent and received among network entities,and actions taken on message transmission,receipt Introduction1-8

Introduction What’s a protocol? human protocols: ▪ “what’s the time?” ▪ “I have a question” ▪ introductions … specific messages sent … specific actions taken when messages received, or other events network protocols: ▪ machines rather than humans ▪ all communication activity in Internet governed by protocols protocols define format, order of messages sent and received among network entities, and actions taken on message transmission, receipt 1-8

What's a protocol? a human protocol and a computer network protocol: Hi TCP connection request Hi TCP connection response Got the time? Get http://www.awicom/kurose-ross +—2:00 time Q:other human protocols? Introduction1-9

Introduction a human protocol and a computer network protocol: Q: other human protocols? Hi Hi Got the time? 2:00 TCP connection response Get http://www.awl.com/kurose-ross time TCP connection request What’s a protocol? 1-9

Chapter I:roadmap 1.I what is the Internet? 1.2 network edge end systems,access networks,links 1.3 network core packet switching,circuit switching,network structure 1.4 delay,loss,throughput in networks 1.5 protocol layers,service models 1.6 networks under attack:security 1.7 history Introduction1-10

Introduction Chapter 1: roadmap 1.1 what is the Internet? 1.2 network edge ▪ end systems, access networks, links 1.3 network core ▪ packet switching, circuit switching, network structure 1.4 delay, loss, throughput in networks 1.5 protocol layers, service models 1.6 networks under attack: security 1.7 history 1-10