2. Computer Networking

3. Department of Computer Networking Application CHAPTER 1 Introduction overview 1 The first section 2 Exercises 3 Online lecture

4. Chapter 1 Introduction overview 1 Andrew S.Tanenbaum, Computer Networks, 4 rd ed, Prentice Hall, 2003 ( 4 ),, 2 3 William Stallings 4 Douglas E.Comer

5. www.gxmu.edu.cn Computer Networking A Top-Down Approach Featuring the Internet James F. Kurose and Keith W. Ross Chapter 1 Introduction overview

6. www.gxmu.edu.cn Computer networking Author Rowe, Stanford H Rowe, Schuh, Marsha L Schuh Chinese http://books.google.cn/books?id=oqgDJmdBECMC English http://books.google.cn/books?id=S_Ft-9l1RGcC Chapter 1 Introduction overview

7. www.gxmu.edu.cn Master Basic network theory 1 Get certified 2 Join and participate in professional associations 3 Experience 4 Chapter 1 Introduction overview

8. www.gxmu.edu.cn Certificate Chapter 1 Introduction overview

9. www.gxmu.edu.cn INTRODUCTION AND OVERVIEW Chapter 1 Introduction overview Introduction Overview 1 Network Classification 2 Network Architectures 3 Introduction Protocols 4

10. www.gxmu.edu.cn OBJECTIVES Chapter 1 Introduction overview 1 Explain what a network is ; 2 Explain the terms communications,t elecommunication s,and network; 3 Describe the history of networks;

11. www.gxmu.edu.cn 1.2 WHY STUDY NETWORKS? A. Hope to work in a communications. Good salary B. Have more of an academic interest want to understand more networks about how to work. C.Expand your computer network vocabulary. Chapter 1 Introduction overview

12. www.gxmu.edu.cn It industry professionals on the needs of the situation Source Chapter 1 Introduction overview

13. www.gxmu.edu.cn 1.3 THE SCOPE OF THIS BOOK Learn about networking Focus :industry,education, government No complicated Mathematics Provides a solid foundation Chapter 1 Introduction overview

14. www.gxmu.edu.cn 1.4 TERMINOLOGY 1.4.1 Communication A) A process that allows information to pass between a sender and one or more receivers. B) The art of expressing ideas especially in speech and writing. And the science of transmitting meaningful information,especially in symbols. Chapter 1 Introduction overview

15. www.gxmu.edu.cn 1.4.2 Telecommunication Telecommunication is the assisted transmission of signals over a distance for the purpose of communication. Telecommunication=communication Chapter 1 Introduction overview

16. www.gxmu.edu.cn 1.4.3 Network A network can be thought of as an interrelated group of objects connected together in some way Chapter 1 Introduction overview

17. www.gxmu.edu.cn Computer network A communication network is an interconnected system of computers, terminals, and other hardware established for the purpose of exchanging information or service between individuals, groups, or institutions. Chapter 1 Introduction overview

18. www.gxmu.edu.cn Computer networks consist of 1 Physical connections: Cable, optical fiber, radio channel. 2 Communication protocols: Defining the format, timing of signals/packets at different layers. Different protocols make different network systems. 3 Applications: Client/server programs for different services. Chapter 1 Introduction overview

19. www.gxmu.edu.cn 1.4.4 Acronyms Chapter 1 Introduction overview

20. www.gxmu.edu.cn 1.5 BASIC ELEMENTS OF A NETWORK A network contains three basic elements: Source: The transmitter or sender of a message is also called the source. Sink : receiver Chapter 1 Introduction overview

21. www.gxmu.edu.cn Medium: The vehicle through which a message travels from sender to receiver A copper wire fiber microwave infrared The medium as the communication line, the line,or the circuit. Chapter 1 Introduction overview

22. www.gxmu.edu.cn Figure 1-1 Basic elements of a communication network. A copper wire in a telephone network is an example of a medium. Chapter 1 Introduction overview

23. www.gxmu.edu.cn Protocols The rules of communication that guide the progress of messages through a network. To ensure that messages sent on a network will be successfully received, rules must guide their progress. Chapter 1 Introduction overview

24. www.gxmu.edu.cn Figure 1-2 Unwritten rules of telephone communication: the initiation of the conversation. Stanford Rowe and Marsha Schuh Computer Networking, 1e Copyright ©2005 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Protocols are used in voice communication. Chapter 1 Introduction overview

25. www.gxmu.edu.cn Figure 1-3 Shortcutting the unwritten rules of telephone call initiation. Chapter 1 Introduction overview

26. www.gxmu.edu.cn NOTE Protocols are used in voice communication too. Equipment communication must have protocols, All of rules must be defined precisely and must cover all situation. Unlike voice communication examples. Chapter 1 Introduction overview

27. www.gxmu.edu.cn 1.6.1 The Telegraph Network 1.6.2 Early Telephone Networks 1.6 A BRIEF HISTORY OF TELECOMMUNCATIO NETWORKS Early Electrical Telegraph Chapter 1 Introduction overview

28. www.gxmu.edu.cn 1.6.1 The Telegraph The first true telecommunication network was established in the United States in 1844. over 150 years ago Electromagnetic telegraph machine Established the foundation for network developments Telegraph vs. SMS Samuel Morse Chapter 1 Introduction overview

29. www.gxmu.edu.cn Morse Code Chapter 1 Introduction overview

30. www.gxmu.edu.cn 1.6.2 Early Telephone Network Jumped to the problem of sending voice signals. Western Union passed up the opportunity to own the basic patents on the telephone Bell was not instantly successful with telephone technology after he received the patent for his device Bell company –AT&T Two pioneers of the telephone industry were Bell and Gray In 1876. Chapter 1 Introduction overview

31. www.gxmu.edu.cn 1.6.3 Early Teleprinting Service 1846.royal house invented a Printing telegraph machine It was faster than MORS, But it did not eliminate the need for operators. Chapter 1 Introduction overview

32. www.gxmu.edu.cn baudot: Character ------five pulses Emile baudot The first printing telegraph system used the Baudot code. Baudot machines Could do the encoding and decoding. Chapter 1 Introduction overview

33. www.gxmu.edu.cn Baudot rate Baud: A unit of speed in data transmission usually equal to one bit per second. 1 B = 1bit= 1bps Chapter 1 Introduction overview

34. www.gxmu.edu.cn TWX: teletypewriter exchange service AT&T TELEX: teletypewriter Western union. The telex and TWX networks were both developed in the U.S. Telex service is still in limited use today. It is replaced by e-mail. Chapter 1 Introduction overview

35. www.gxmu.edu.cn 1.6.4 Radio Teleprinting 1930s radio teletype, RTTY Al Gross launched a wireless pager in 1949, followed in 1951 invented a wireless phone. Martin Cooper is considered the father of the mobile phone Teleprinter signals could be transmitted by radio Chapter 1 Introduction overview

36. www.gxmu.edu.cn 1.6.5 The Telephone Network Telephone network don't eliminated the need for teleprinting networks and services. CO Central : provides the switching of telephone calls and provides a gathering point for circuits in its area. Chapter 1 Introduction overview

37. www.gxmu.edu.cn Computerized switches Call swithing Early manual telephone switches Telephone operators-mechanical switches-computerized switches telephone switches classification Chapter 1 Introduction overview

38. www.gxmu.edu.cn Computers are not the only devices that can handle switching in networks. Chapter 1 Introduction overview

39. www.gxmu.edu.cn Computerized switches The switching of data, voice, and other signals through a network is done by specialized computers. The average time to connect a telephone call is under three seconds Chapter 1 Introduction overview

40. www.gxmu.edu.cn 1.6.6 Analog and Digital Telephone Service Originally, the telephone and telephone network were entirely analog. Since 1950, has become largely digital in operation. only handset remains analog. Chapter 1 Introduction overview

41. www.gxmu.edu.cn Analog and Digital Signals Signals that are continuous are called analog signals. Signals that have discrete values are called digital signals *Analog communications devices handle signals that vary discretely with time. F *Digital signals have just two states Chapter 1 Introduction overview

42. www.gxmu.edu.cn Figure 1-6 Analog and digital signals in the telephone network. Most telephone handsets are analog devices. Chapter 1 Introduction overview

43. www.gxmu.edu.cn Periodic Signals Aperiodic Signals Chapter 1 Introduction overview

44. www.gxmu.edu.cn Transformation of Information to Signals When an analog signal is converted to digital form it is said to be digitized Chapter 1 Introduction overview

45. www.gxmu.edu.cn Telephone network become digital If tapped into a digital communications circuit, you would not be able to tell whether the signals you saw were computer data, digitized voice signals, or digitized video. There aren't fundamental differences among data, voice, and image transmissions. Chapter 1 Introduction overview

46. www.gxmu.edu.cn Digital telephone DSL- digital subscriber line ADSL: Asymmetric Digital Subscriber Line HDSL: High-data-rate Digital Subscriber Line Most telephone handsets are analog devices. Chapter 1 Introduction overview

47. www.gxmu.edu.cn Networks you may have used include the public switched telephone network (PSTN) the Internet a bank network a supermarket network a credit card network 1.7 Contemporary examples of networks When you make a call on your cell phone, you are using a wireless network. Chapter 1 Introduction overview

48. www.gxmu.edu.cn A computer network may be as simple as two computers in an office connected by a wire or cable. Private companies are allowed to build their own communications networks. Chapter 1 Introduction overview

49. www.gxmu.edu.cn Development of computer network In 1946 The world's first digital computer available. In1954 transceiver Terminal. The basic prototype computer network was born this way Chapter 1 Introduction overview

50. www.gxmu.edu.cn The first generation: Host +terminal The first generation: Host +terminal 1950s Chapter 1 Introduction overview

51. www.gxmu.edu.cn 2G: Host+Host+...... 1960s Pre-Processor Host Pre-Processor Chapter 1 Introduction overview

52. www.gxmu.edu.cn computer network from the 1970s began. 3G computer network from the 1970s began. 1970s Chapter 1 Introduction overview

53. www.gxmu.edu.cn 4G:High-speed computer network technology development 4G:High-speed computer network technology development 1980s Chapter 1 Introduction overview

54. www.gxmu.edu.cn Evolution of network Simple connection Network connectivity Network Interconnection 1960s1970s 1970s1980s 1980S Chapter 1 Introduction overview

55. www.gxmu.edu.cn Ethernet development DIX IEEE 802.3 IEEE 802.3U IEEE 802.3Z/AB IEEE 802.3AE/AK 198019831995199819992002.6 10M 10M 802.3 100M 802.3u 1G 802.3z 1G 802.3ab 10G 802.3ae 2004.2 10G 802.3ak 1973 3M Chapter 1 Introduction overview

56. www.gxmu.edu.cn 2001:05c0:8d16::/48 2001:05c0:8d16:1500::/56 18 21 25 Eagle Tiger Lion Frog Dolphin 159.226.10.198/30 159.226.10.201 / 29 159.226.10.209/ 29 IPv6 2001:05c0:8d16:1205::/64 IPv4 159.226.10.210~214/ 29 IPv6 2001:05c0:8d16:1519::/64 Whale 2001:05c0:8d16:1200::/56 5 Router IPv4 159.226.10.202~206/ 29 IPv6 2001:05c0:8d16:1206::/64 IPv6 IPv6 over IPv4 159.226.10.193 2001:05c0:8fff:fffe::408b/128 159.226.10.197/30 IPv6 2001:05c0:8d16:1520::/64 6 26 IPV6 Test-bed structure IPv4 IPv4/IPv6 IPv6 Chapter 1 Introduction overview

57. www.gxmu.edu.cn NETWORK Research directions in last 10 years The communications regulatory environment changes constantly. Chapter 1 Introduction overview

58. www.gxmu.edu.cn SUMMARY We use network every day Internet and telephone network are most common network. Networks can be classified. Chapter 1 Introduction overview

59. D protocols 1 Rules that guide the progress of messages through a network are called. D A media B circuits C switches Answer Redo Next × × × Exercises Chapter 1 Introduction overview

60. D All of the above. 2 Telephone signals are. D A normally converted to digital form at some point during their transmission B switched by computers C transmitted through a communication companys CO Answer Redo Next × × × Exercises Chapter 1 Introduction overview

61. A Bell and Gray 3.Two pioneers of the telephone industry were. A B control character D Rowe and Schuh C Baudot and Murray Answer Redo Next × × × Exercises Chapter 1 Introduction overview

62. C both developed in the U.S 4.The telex and TWX networks were. C A different names for the same service B early telephone services D None of the above. Answer Redo Next × × × Exercises Chapter 1 Introduction overview

63. D None of the above. 5. To use a network you must always. D A be a registered user B have a password C have basic PC skills Answer Redo Next × × × Exercises Chapter 1 Introduction overview

64. 6. The transmitter or sender of a message is also called the ________ source Answer Exercises 7. The vehicle through which a message travels from sender to receiver is called the ______________. medium Answer 8.A set of rules that guide the progress of a message from sender to receiver is called a__________________. protocol Answer Chapter 1 Introduction overview

65. 9. The company that passed up the opportunity to own the basic patents on the telephone was___________. Western Union Answer Exercises 10.Signals that are continuous are called ________________. canalog signals Answer Chapter 1 Introduction overview