A Brief History of the Internet

1. A Brief History of the Internet

2. Internet: The early years … The Proliferation of LANs • Engineers have devised many LAN technologies • LAN performance determines cost; high performance LANs are more expensive • A particular LAN technology may only work with specific computers

3. Internet: The early years … The Proliferation of LANs Star topology

4. Internet: The early years … The Proliferation of LANs Ring topology

5. Internet: The early years … The Proliferation of LANs Bus topology

6. Internet: The early years … The Proliferation of LANs Ethernet sharing

7. Internet: The early years … The Proliferation of LANs • A LAN technology is chosen for its speed, ease of use, and the availability of interfaces for specific computers. Most large organization use many LAN technologies

8. Internet: The early years … LANs are incompatible • Various LAN technologies are completely incompatible. Accounting Dept. Shipping Dept.

9. Internet: The early years … LANs are incompatible • Various LAN technologies are completely incompatible. Simply connecting the cables cannot make them work together Accounting Dept. Shipping Dept.

10. Internet: The early years … Wide Area Technologies Exist A wide area network technology (WAN) differs from a set of disjoint transmission lines because the WAN includes an additional special purpose computer at each side that connects to the transmission lines and keeps communication independent of the computers that use the WAN

11. Internet: The early years … Wide Area Technologies Exist

12. Internet: The early years … • Few WANs, Many LANs • WANs and LANs are Incompatible • Many LAN and WAN technologies exist, and most are incompatible with each other. One cannot produce a usable, large network merely by interconnecting the wires from two different networks.

13. Internet: The early years … • The Desirability of A Single Network …

14. Internet: The early years … • The Internet Emerges … • ARPANET … • Advanced Research Project Agency (ARPA) funded research projects to research new approaches to connecting LANs and WANs. • A prototype system that researchers built became known as an internetwork – Internet.

15. Internet: The early years … • The Internet Emerges … Diagrams of two nodes on the ARPANET IMP - Interface Message Processors

16. Internet: The early years … • The Internet Emerges …

17. Internet: The early years … • The Internet Emerges …

18. Internet: The early years … • Internet Software • Computer software forms an important part of the technology that makes it possible to interconnect networks

19. Internet: The early years … • The Name is TCP/IP • Two pieces of Internet software stand out as particularly important and innovative • Internet Protocol – software provide basic communication • Transmission Control Protocol – Provide reliable communication

20. Internet: The early years … • An Open System • The Internet project aspired to produce an open system that permitted computers from all vendors to communicate.

21. Internet: The early years … • Summary … • The Internet began as a research project funded by ARPA. Researchers studied ways to connect computers that used various kinds of networks. The name Internet refers to both the project and the prototype network system that researchers built. • TCP/IP is the software necessary to make the Internet works. The software hides the detail of the underlying hardware and provides the illusion of a seamless system. • The Internet is an open system.

22. Internet: Incredible Growth • 1981 – The Internet connects about 100 computers at research sites and universities • 20 years later – 60,000,000 Year #computers Year #computers 1983 562 1991 500,000 1984 1,024 1992 727,000 1985 1,961 1993 1,200,000 1986 2,308 1994 2,217,000 1987 5,089 1995 4,852,000 1988 28,174 1996 9,472,000 1989 80,000 1990 290,000

23. Internet: Incredible Growth

24. Internet: Incredible Growth By 1999; a computer was added to the Internet every second.

25. Internet: Incredible Growth By 2006; more than 10 computers were added to the Internet every second.

26. Internet: Incredible Growth • Factors contribute to its growth … • Advances in computer science research – the introduction of UNIX operating system • UNIX meets TCP/IP – enables connection of LANs to the Internet • US Military Chose the Internet – The military funded and adopted the Internet, technologies were developed at civilian sites

27. Internet: Incredible Growth • Factors contribute to its growth … • National Science Foundation (NSF) Takes a Leading Role – connect universities to the Internet • NSF decided that to keep the US competitive, it needed to extend network access to every science and engineering researcher. • The NSFNET

28. Internet: Incredible Growth • Factors contribute to its growth … • The NSFNET Backbone

29. Internet: Incredible Growth • Factors contribute to its growth … • The ANS Backbone – IBM, MERIT, and MCI formed a nonprofit company, Advanced Networks and Services (ANS) • ANS owned the transmission lines and computers that comprised the network – ARPANET and NSFNET were funded by government • First step toward commercialization and privatization of the Internet

30. The Global Internet • Internet starts from the USA …expanded to the globe • Electronic mail connection – use existing voice telephone network – require a modem and a piece of communication software

31. The Global Internet • Internet starts from the USA …expanded to the globe • In the UK … JANET

32. The Global Internet • Internet starts from the USA …expanded to the globe • In Europe … Ebone

33. The Global Internet • Internet starts from the USA …expanded to the globe • In Hong Kong … HARNET

34. The Global Internet 1998, every populated country in the world is connected

35. Internet: A Global Information Infrastructure • Infrastructure – basic foundations on which society depends on – electricity power stations and supply facilities, railways, roads … • New infrastructure makes new industries possible

36. Internet: A Global Information Infrastructure • Communication Infrastructure • Postal mail services adopted the nation of universal access and delivery; and individual and send a letter to any other individual. • The telegraph changed the basic communication infrastructure because it introduced high speed delivery • Telephone changed the communication infrastructure by extending communication services to individual homes and offices, and by providing the instantaneous communication needed for interactive conversation

37. Internet: A Global Information Infrastructure • The Internet Infrastructure • The basic Internet communication facilities are both general and efficient, almost any network applications can use the Internet • The Internet offers a wide variety of services. Most of the services currently available had not been invented when the Internet was first designed. • The Internet is a global infrastructure. Although it offers many services, the Internet’s chief advantage lies in the design of TCP/IP software that has accommodated changes in computers, networks, and services

38. Summary • Many different LAN technologies that are completely incompatible. • WANs exist • Few WANs, Many LANs • WAN and LAN are incompatible • Desirable to have a single seamless network

39. Summary • ARPANET • ICP/IP • Open Systems • Computer science research, UNIX, NSFNET, TCP/IP … contributed to the rapid growth of the Internet. • Internet is a global information infrastructure.

40. Sharing transmission path Communication Path

41. Sharing transmission path Sharing saves cost Communication Path

42. Sharing transmission path Sharing introduces delay Communication Path

43. Sharing transmission path Sharing introduces delay Communication Path

44. Sharing using Selectable Channels Carrier 1 Communication Path Carrier 2

45. Sharing using Selectable Channels Each channel is assigned a unique carrier which encodes the information of that communication channel Carrier 1 Communication Path Carrier 2

46. Sharing by Taking Turns C A Divide data to be transmitted into small trunks, call a packet; and transmit one packet at a time D B Data to be transmitted

47. Sharing by Taking Turns C 1st packet from B to D A B|C A|C B|D A|C D B 1st packet from A to C 1st packet from B to C 2nd packet from A to C

48. Packet Switching Sharing by Taking Turns C 1st packet from B to D A B|C A|C B|D A|C D B 1st packet from A to C 1st packet from B to C 2nd packet from A to C

49. Packet Switching Avoids Delay

50. Packet Switching Avoids Delay A customer ordered a single item Another ordered 50 items