EE 122: Introduction to Computer Networks – Fall 2002TAsOverviewAdministrative Trivia’sGoals of this CourseWhat Do You Need To Do?GradingSlide 8What is a Communication Network? (from end-system point of view)What is a Communication Network? Infrastructure Centric ViewTypes of NetworksSlide 12The InternetHistory of the InternetGrowth of the InternetRecent Growth (1991-2002)Services Provided by the InternetCommercial Internet after 1994Internet Physical InfrastructurePowerPoint PresentationSlide 21Slide 22Slide 23A Taxonomy of Communication NetworksBroadcast vs. Switched Communication NetworksSlide 26Circuit SwitchingTiming in Circuit SwitchingSlide 29Circuit Switching: Multiplexing/DemultiplexingSlide 31Packet SwitchingSlide 33Packet Switching: Multiplexing/DemultiplexingSlide 35Datagram Packet SwitchingTiming of Datagram Packet SwitchingSlide 38Slide 39Virtual-Circuit Packet SwitchingSlide 41Slide 42Slide 43Packet-Switching vs. Circuit-SwitchingSummaryIon Stoica, Fall 20021EE 122: Introduction to Computer Networks – Fall 2002Instructors-Ion Stoica ([email protected], 645 Soda Hall)-Kevin Lai ([email protected], 445 Soda Hall)Lecture time-Monday/Wednesday, 4:00 – 5:30pmOffice hour:-Monday, 2-3pm Class Web page-http://inst.eecs.berkeley.edu/~ee122/Textbook-L. L. Peterson and B. Davie, Computer Networks – A System Approach, 2nd Edition, Morgan Kaufman, 2000Ion Stoica, Fall 20022TAsWeidong Cui, [email protected]Xuanming Dong, [email protected]Karthik Lakshminarayanan, [email protected]Anantha Rajagopala-Rao (AP), [email protected]Office hours and recitations to be announced by Wednesday!Ion Stoica, Fall 20023OverviewAdministrative triviaOverview and history of the InternetA Taxonomy of Communication NetworksIon Stoica, Fall 20024Administrative Trivia’sCourse Web page: -http://inst.eecs.berkeley.edu/~ee122/-Check it periodically to get the latest informationDeadline means deadline-Homeworks: unless otherwise specified, it means 3:50 pm on the date (10 minutes before lecture)Exams are closed-bookBest way to communicate: e-mail-But contact your TA first !Please let us know any suggestions/complaints about class as early as possibleIon Stoica, Fall 20025Goals of this CourseLearn the main concepts of communication networks in general, and Internet in particular-Understand how the Internet works-Try to understand why the Internet is the way it isApply what you learned in small scale class projectsIon Stoica, Fall 20026What Do You Need To Do?Four homeworks-Strict deadlinesTwo projects-Four slip days. Any additional day –20%One midterm examOne final examIon Stoica, Fall 20027GradingHomeworks 20%Two projects 30%Midterm exam 20%Final exam 30%Ion Stoica, Fall 20028OverviewAdministrative triviaOverview and history of the InternetA Taxonomy of Communication NetworksIon Stoica, Fall 20029What is a Communication Network?(from end-system point of view)Network offers a service: move information-Bird, fire, messenger, truck, telegraph, telephone, Internet …-Another example, transportation service: move objects•Horse, train, truck, airplane ...What distinguish different types of networks?-The services they provideWhat distinguish the services?-Latency-Bandwidth-Loss rate-Number of end systems-Service interface (how to invoke the service?)-Other details•Reliability, unicast vs. multicast, real-time, message vs. byte ...Ion Stoica, Fall 200210What is a Communication Network?Infrastructure Centric ViewElectrons and photons as communication mediumLinks: fiber, copper, satellite, …Switches: electronic/optic, crossbar/BanyanProtocols: TCP/IP, ATM, MPLS, SONET, Ethernet, X.25, FrameRelay, AppleTalk, IPX, SNAFunctionalities: routing, error control, flow control, congestion control, Quality of Service (QoS)Applications: FTP, WEB, X windows, ...Ion Stoica, Fall 200211Types of NetworksGeographical distance-Local Area Networks (LAN): Ethernet, Token ring, FDDI-Metropolitan Area Networks (MAN): DQDB, SMDS-Wide Area Networks (WAN): X.25, ATM, frame relay-Caveat: LAN, MAN, WAN may mean different things•Service, network technology, networksInformation type-Data networks vs. telecommunication networksApplication type-Special purpose networks: airline reservation network, banking network, credit card network, telephony -General purpose network: InternetIon Stoica, Fall 200212Types of NetworksRight to use-Private: enterprise networks-Public: telephony network, InternetOwnership of protocols-Proprietary: SNA-Open: IPTechnologies-Terrestrial vs. satellite-Wired vs. wirelessProtocols-IP, AppleTalk, SNAIon Stoica, Fall 200213The InternetGlobal scale, general purpose, heterogeneous-technologies, public, computer networkInternet Protocol-Open standard: Internet Engineering Task Force (IETF) as standard body ( http://www.ietf.org )-Technical basis for other types of networks•Intranet: enterprise IP networkDeveloped by the research communityIon Stoica, Fall 200214History of the Internet70’s: started as a research project, 56 kbps, < 100 computers80-83: ARPANET and MILNET split 85-86: NSF builds NSFNET as backbone, links 6 Supercomputer centers, 1.5 Mbps, 10,000 computers87-90: link regional networks, NSI (NASA), ESNet(DOE), DARTnet, TWBNet (DARPA), 100,000 computers90-92: NSFNET moves to 45 Mbps, 16 mid-level networks94: NSF backbone dismantled, multiple private backbonesToday: backbones run at 2.4 Gbps, 200 millions computers in 150 countriesIon Stoica, Fall 200215Growth of the InternetNumber of Hosts on the Internet:Aug. 1981 213Oct. 1984 1,024Dec. 1987 28,174 Oct. 1990 313,000 Oct. 1993 2,056,000Apr. 1995 5,706,000Jul. 1997 19,540,000Jul. 1999 59,249,900Jun. 2002 200,071,00011010010001000010000010000001000000010000000010000000001981 1984 1987 1990 1993 1996 1999 2002Data available at: http://www.netsizer.com/Ion Stoica, Fall 200216Recent Growth (1991-2002)Ion Stoica, Fall 200217Services Provided by the InternetShared access to computing resources-telnet (1970’s)Shared access to data/files-FTP, NFS, AFS (1980’s)Communication medium over which people interact-email (1980’s), on-line chat rooms, instant messaging (1990’s)-audio, video (1990’s) •replacing telephone network?A medium for information dissemination-USENET
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