EE 122 Introduction to Computer Networks Fall 2001 Instructor Ion Stoica istoica cs berkeley edu 645 Soda Hall Lecture time Tu Th 9 30 11 00 Office hour Thursday 11 15 12 15 pm Class Web page http www cs berkeley edu istoica ee122 Ion Stoica Fall 2001 1 TAs Eiman Zolfaghari eiman uclink berkeley edu Monday 11 00 12 00 Anshuman Sharma vulcan eecs berkeley edu Monday 3 00 4 00 Abhishek Ghose aghose eecs berkeley edu Monday 4 00 5 00 Sridhar Machiraju machi eecs berkeley edu Wednesday 10 00 11 00 Barath Raghavan barath uclink4 berkeley edu Wednesday 3 00 4 00 Chunlong Guo along eecs berkeley edu Friday 11 0012 00 Dragan Petrovic dragan eecs berkeley edu Friday 2 00 3 00 Ion Stoica Fall 2001 2 Overview Administrative trivia Overview and history of the Internet A Taxonomy of Communication Networks Router Architecture in Packet Switching Networks Ion Stoica Fall 2001 3 Administrative Trivia s Course Web page http www cs berkeley edu istoica ee122 check it periodically to get the latest information Deadline means deadline unless otherwise specified it means 9 20 pm on the date 10 minutes before lecture special circumstances should be brought to my or TAs attention way ahead of deadlines Exams are closed book Best way to communicate e mail but contact your TA first Ion Stoica Fall 2001 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 2001 5 What Do You Need To Do Five homeworks Two projects Two midterm exams Final exam Ion Stoica Fall 2001 6 Grading Ion Stoica Fall 2001 Homeworks 20 Two projects 30 Midterm exams 20 Final exam 30 7 Overview Administrative trivia Overview and history of the Internet A Taxonomy of Communication Networks Router Architecture in Packet Switching Networks Ion Stoica Fall 2001 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 2001 9 What is a Communication Network Infrastructure Centric View Electrons and photons as communication medium Links fiber copper satellite Switches mechanical electronic optical crossbar Banyan Protocols TCP IP ATM MPLS SONET Ethernet PPP X 25 FrameRelay AppleTalk IPX SNA Functionalities routing error control congestion control Quality of Service QoS Applications FTP WEB X windows Ion Stoica Fall 2001 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 2001 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 2001 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 2001 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 10s millions computers in 150 countries Ion Stoica Fall 2001 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 Jul 2001 117 288 000 Ion Stoica Fall 2001 1000000000 100000000 10000000 1000000 100000 10000 1000 100 10 1 1981 1984 1987 1990 1993 1996 1999 Data available at http www netsizer com 15 Recent Growth 1991 2000 Ion Stoica Fall 2001 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 2001 17 Today s Vision Everything is digital voice video music pictures live events Everything is on line bank statement medical record books airline schedule weather highway traffic toaster refrigerator Everyone is connected doctor teacher broker mother son friends enemies Ion Stoica Fall 2001 18 What is Next Electronic commerce virtual enterprise Internet entertainment interactive sitcom World as a small village community organized according to interests enhanced understanding among diverse groups Electronic democracy little people can voice their opinions to the whole world little people can coordinate their actions bridge the gap between information haves and have no s Electronic terrorism hacker can bring the whole world to its knee Ion Stoica Fall 2001 19 Industrial Players Telephone companies own long haul and access communication links customers Cable companies own access links Wireless Satellite companies alternative communication links Utility companies power water railway own right of way to lay down more wires Medium companies own content Internet Service Providers Equipment companies switches routers chips optics computers Software companies Ion Stoica Fall 2001 20
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