Computer NetworksZhang Jinglei Based on the slides by Jim Kurose and Keith Ross1 IntroductionAbout InstructorqLecturer from 1999 qAnti professor from 2008 qMS from 1996-1999 Tianjin University qPhD CandidateqResearch Interests:mImage ProcessingmComputer VisionmPattern Recognition mIndustrial Networks (Fieldbus) qContact InformationmOffice 14-312mOffice Phone 60214105mEmail: zjlmailbox126.com2 IntroductionAbout this courseqTextbookmComputer Networking: A Top Down Approach Featuring the Internet, 3rd edition. Jim Kurose, Keith Ross Addison-Wesley, July 2004. qGrading:mHomework 20%mLab 10% mFinal exam 70%3 IntroductionWhat we should knowqList some cool ideas or killer applications for networksqList some influential companies in area of networksqList some influential technologies in networksqList some good journals in area of networksqList some good conferences in networks4 IntroductionOrganization of ClassqIntroduction: Computer Networks and InternetqApplications of Internet: http, ftp, P2P,qTransportation Layer: TCP, UDP,qThe Network Layer: IP, routingsqLink Layer: Errors, MAC, Ethernet,qWireless and Mobile Networks: cellular, ad hoc, sensor,qIndustrial NetworksInfranetqInterconnection between Industrial Networks and Internet,Intranet.5 IntroductionChapter 1 IntroductionComputer Networking: A Top Down Approach Featuring the Internet, 3rd edition. Jim Kurose, Keith Ross Addison-Wesley, July 2004. The majority of the slides are based on the draft byJ.F. Kurose and K.W. Ross.6 IntroductionChapter 1: IntroductionOur goal: qget “feel” and terminologyqmore depth, detail later in courseqapproach:muse Internet as exampleOverview:qwhats the Internetqwhats a protocol?qnetwork edgeqnetwork coreqaccess net, physical mediaqInternet/ISP structureqperformance: loss, delayqprotocol layers, service modelsqnetwork modeling7 IntroductionChapter 1: roadmap1.1 What is the Internet? 1.2 Network edge 1.3 Network core 1.4 Network access and physical media 1.5 Internet structure and ISPs 1.6 Delay email client/serverqpeer-peer model:m minimal (or no) use of dedicated serversme.g. Gnutella, KaZaA16 IntroductionNetwork edge: connection-oriented serviceGoal: data transfer between end systemsqhandshaking: setup (prepare for) data transfer ahead of timemHello, hello back human protocolmset up “state” in two communicating hostsqTCP - Transmission Control Protocol mInternets connection- oriented serviceTCP service RFC 793qreliable, in-order byte- stream data transfermloss: acknowledgements and retransmissionsqflow control: msender wont overwhelm receiverqcongestion control: msenders “slow down sending rate” when network congested17 IntroductionNetwork edge: connectionless serviceGoal: data transfer between end systemsmsame as before!qUDP - User Datagram Protocol RFC 768: mconnectionless munreliable data transfermno flow controlmno congestion controlApps using TCP: qHTTP (Web), FTP (file transfer), Telnet (remote login), SMTP (simple mail transfer protocol-email)Apps using UDP:qstreaming media, teleconferencing, DNS, Internet telephony18 IntroductionChapter 1: roadmap1.1 What is the Internet? 1.2 Network edge 1.3 Network core 1.4 Network access and physical media 1.5 Internet structure and ISPs 1.6 Delay No effective payment systems; Credit card?mPeople uncomfortable sending credit card numbers over InternetmIf information not encrypted it is easy to “listen in”mSeveral files of customers credit card numbers on merchants computers have been compromisedqPrivacy concernsm“data mining,” Collecting customer transaction information to improve targeting of marketing 104 IntroductionIntroduction: SummaryCovered a “ton” of material!qInternet overviewqwhats a protocol?qnetwork edge, core, access networkmpacket-switching versus circuit-switchingqInternet/ISP structureqperformance: loss, delayqlayering and service modelsqhistoryYou now have: qcontext, overview, “feel” of networkingqmore depth, detail to follow!105 Introduction