Slide 1Slide 2Slide 3Slide 4Slide 6Slide 7Slide 9Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 26Slide 27Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 36Slide 39Slide 41Slide 43Slide 44Slide 45Slide 46Slide 47Slide 48Slide 49Slide 50Slide 51Slide 52Slide 56Slide 57Slide 58Slide 59Slide 63Slide 64Slide 65Slide 67Slide 68Slide 70Slide 71Slide 72Slide 73Slide 74Slide 80Slide 81Slide 82Slide 83Slide 84Slide 85Slide 86Introduction 1-1CS 118 Spring 2014Computer NetworksLecture 1Mario Gerla/ Songwu [email protected]@cs.ucla.eduIntroduction 1-2Chapter 1IntroductionA note on the use of these ppt slides:We’re making these slides freely available to all (faculty, students, readers). They’re in PowerPoint form so you 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) in substantially unaltered form, that you mention their source (after all, we’d like people to use our book!) If you post any slides in substantially unaltered form 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/KWRAll material copyright 1996-2007J.F Kurose and K.W. Ross, All Rights Reserved1: Introduction 3CS 118 Computer Network FundamentalsMario Gerla, 3732 F BH/Songwu Lu 4731 C BH[email protected] 310 825 4367 [email protected] 310 825 4033Gerla - Office hrs Monday 2-3, Thursday 10-11 or by appointmentCourse objectives: (a) qualitative study of the fundaments protocol layers in the Internet protocol suite; (b) exposure to very basic network programming through projects; (c ) basic knowledge required to move on to advanced (graduate) network/system coursesCourse grading: Class Participation 3%Homework 10%Midterm 22%Final 35%Projects 30% Total 100%More about Course AdminLecture MW 8:00 AM - 9:50 AM HAINES A18TA 1 Xiao Li ([email protected])TA2 Jihyoung Kim ([email protected])Discussion 1A F 2:00 PM - 3:50 PM BOELTER 5264Discussion 1B F 4:00 PM - 5:50 PM BOELTER 5273Discussion 1C F 2:00 PM - 3:50 PM LAKRETZ 120 Introduction 1-4Introduction 1-6Chapter 1: roadmap1.1 What is the Internet?1.2 Network edge end systems, access networks, links1.3 Network core circuit switching, packet switching, network structure1.4 Delay, loss and throughput in packet-switched networks1.5 Protocol layers, service models1.6 Networks under attack: security1.7 HistoryIntroduction 1-7What’s the Internet: “nuts and bolts” viewmillions of connected computing devices: hosts = end systems running network appsHome networkInstitutional networkMobile networkGlobal ISPRegional ISProuterPCserverwirelesslaptopcellular handheldwiredlinksaccess pointscommunication linksfiber, copper, radio, satellitetransmission rate = bandwidthrouters: forward packets (chunks of data)Introduction 1-9What’s the Internet: “nuts and bolts” viewprotocols control sending, receiving of msgse.g., TCP, IP, HTTP, Skype, EthernetInternet: “network of networks”loosely hierarchicalpublic Internet versus private intranetInternet standardsRFC: Request for commentsIETF: Internet Engineering Task ForceHome networkInstitutional networkMobile networkGlobal ISPRegional ISPIntroduction 1-11What’s a protocol?human protocols:“what’s the time?”“I have a question”introductions… specific msgs sent… specific actions taken when msgs received, or other eventsnetwork protocols:machines rather than humansall communication activity in Internet governed by protocolsprotocols define format, order of msgs sent and received among network entities, and actions taken on msg transmission, receiptIntroduction 1-12What’s a protocol?a human protocol and a computer network protocol:Q: Other human protocols? HiHiGot thetime?2:00TCP connection requestTCP connectionresponseGet http://www.awl.com/kurose-ross<file>timeIntroduction 1-13Chapter 1: roadmap1.1 What is the Internet?1.2 Network edge end systems, access networks, links1.3 Network core circuit switching, packet switching, network structure1.4 Delay, loss and throughput in packet-switched networks1.5 Protocol layers, service models1.6 Networks under attack: security1.7 HistoryIntroduction 1-14A closer look at network structure:network edge: applications and hostsaccess networks, physical media: wired, wireless communication links network core: interconnected routersnetwork of networksIntroduction 1-15The network edge:end systems (hosts):run application programse.g. Web, emailat “edge of network”client/serverpeer-peerclient/server modelclient host requests, receives service from always-on servere.g. Web browser/server; email client/serverpeer-peer model: minimal (or no) use of dedicated serverse.g. Skype, BitTorrentIntroduction 1-16Network edge: reliable data transfer serviceGoal: data transfer between end systemshandshaking: setup (prepare for) data transfer ahead of timeHello, hello back human protocolset up “state” in two communicating hostsTCP - Transmission Control Protocol Internet’s reliable data transfer serviceTCP service [RFC 793]reliable, in-order byte-stream data transferloss: acknowledgements and retransmissionsflow control: sender won’t overwhelm receivercongestion control: senders “slow down sending rate” when network congestedIntroduction 1-17Network edge: best effort (unreliable) data transfer serviceGoal: data transfer between end systemssame as before!UDP - User Datagram Protocol [RFC 768]: connectionless unreliable data transferno flow controlno congestion controlApp’s using TCP: HTTP (Web), FTP (file transfer), Telnet (remote login), SMTP (email)App’s using UDP:streaming media, teleconferencing, DNS, Internet telephonyIntroduction 1-18Access networks and physical mediaQ: How to connect end systems to edge router?residential access netsinstitutional access networks (school, company)mobile access networksKeep in mind: bandwidth (bits per second) of access network?shared or dedicated?Introduction 1-26Company access: local area networkscompany/univ local area network (LAN) connects end
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