EE 122 Introduction to Computer Networks Fall 2002 Instructors Ion Stoica istoica cs berkeley edu 645 Soda Hall Kevin Lai laik cs berkeley edu 445 Soda Hall Lecture time Monday Wednesday 4 00 5 30pm Office 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 2000 Ion Stoica Fall 2002 1 TAs Weidong Cui wdc eecs berkeley edu Xuanming Dong xuanming eecs berkeley edu Karthik Lakshminarayanan karthik eecs berkeley edu Anantha Rajagopala Rao AP ananthar eecs berkeley edu Office hours and recitations to be announced by Wednesday Ion Stoica Fall 2002 2 Overview Administrative trivia Overview and history of the Internet A Taxonomy of Communication Networks Ion Stoica Fall 2002 3 Administrative Trivia s Course Web page http inst eecs berkeley edu ee122 Check it periodically to get the latest information Deadline means deadline Homeworks unless otherwise specified it means 3 50 pm on the date 10 minutes before lecture Exams are closed book Best way to communicate e mail But contact your TA first Please let us know any suggestions complaints about class as early as possible Ion Stoica Fall 2002 4 Goals of this Course Learn 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 is Apply what you learned in small scale class projects Ion Stoica Fall 2002 5 What Do You Need To Do Four homeworks Strict deadlines Two projects Four slip days Any additional day 20 One midterm exam One final exam Ion Stoica Fall 2002 6 Grading Ion Stoica Fall 2002 Homeworks 20 Two projects 30 Midterm exam 20 Final exam 30 7 Overview Administrative trivia Overview and history of the Internet A Taxonomy of Communication Networks Ion Stoica Fall 2002 8 What 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 provide What 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 2002 9 What is a Communication Network Infrastructure Centric View Electrons and photons as communication medium Links fiber copper satellite Switches electronic optic crossbar Banyan Protocols TCP IP ATM MPLS SONET Ethernet X 25 FrameRelay AppleTalk IPX SNA Functionalities routing error control flow control congestion control Quality of Service QoS Applications FTP WEB X windows Ion Stoica Fall 2002 10 Types of Networks Geographical 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 networks Information type Data networks vs telecommunication networks Application type Special purpose networks airline reservation network banking network credit card network telephony General purpose network Internet Ion Stoica Fall 2002 11 Types of Networks Right to use Private enterprise networks Public telephony network Internet Ownership of protocols Proprietary SNA Open IP Technologies Terrestrial vs satellite Wired vs wireless Protocols IP AppleTalk SNA Ion Stoica Fall 2002 12 The Internet Global scale general purpose heterogeneoustechnologies public computer network Internet 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 network Developed by the research community Ion Stoica Fall 2002 13 History of the Internet 70 s started as a research project 56 kbps 100 computers 80 83 ARPANET and MILNET split 85 86 NSF builds NSFNET as backbone links 6 Supercomputer centers 1 5 Mbps 10 000 computers 87 90 link regional networks NSI NASA ESNet DOE DARTnet TWBNet DARPA 100 000 computers 90 92 NSFNET moves to 45 Mbps 16 mid level networks 94 NSF backbone dismantled multiple private backbones Today backbones run at 2 4 Gbps 200 millions computers in 150 countries Ion Stoica Fall 2002 14 Growth of the Internet Number of Hosts on the Internet Aug 1981 213 Oct 1984 1 024 Dec 1987 28 174 Oct 1990 313 000 Oct 1993 2 056 000 Apr 1995 5 706 000 Jul 1997 19 540 000 Jul 1999 59 249 900 Jun 2002 200 071 000 Ion Stoica Fall 2002 1000000000 100000000 10000000 1000000 100000 10000 1000 100 10 1 1981 1984 1987 1990 1993 1996 1999 2002 Data available at http www netsizer com 15 Recent Growth 1991 2002 Ion Stoica Fall 2002 16 Services Provided by the Internet Shared 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 1980 s WWW 1990 s replacing newspaper magazine audio video 1990 s replacing radio CD TV Ion Stoica Fall 2002 17 Commercial Internet after 1994 Joe s Company Campus Network Berkeley Stanford Regional ISP Bartnet Xerox Parc SprintNet America On Line UUnet NSF Network IBM NSF Network Modem AT T IBM Ion Stoica Fall 2002 18 Internet Physical Infrastructure ISP Residential Access Modem DSL Cable modem Satellite Ion Stoica Fall 2002 Backbone ISP Enterprise ISP access Backbone transmission T1 T3 DS 1 DS 3 OC 3 OC 12 ATM vs SONET vs WDM Campus network Ethernet ATM Internet Service Providers access regional backbone Point of Presence POP Network Access Point NAP 19 Ion Stoica Fall 2002 20 Ion Stoica Fall 2002 21 Ion Stoica Fall 2002 22 Overview Administrative trivia Overview and history of the Internet A Taxonomy of Communication Networks Ion Stoica Fall 2002 23 A Taxonomy of Communication Networks Communication networks can be classified based on the way in which the nodes exchange information Communication Network Switched Communication Network CircuitSwitched Communication Network PacketSwitched Communication Network Datagram Network Ion Stoica Fall 2002 Broadcast Communication Network Virtual Circuit Network 24 Broadcast vs Switched Communication Networks Broadcast communication networks Information transmitted by any node is received by every other node in the network
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