Introduction to Communications Part One: Overview Kuang Chiu Huang TCM NCKU Spring/2008

Information Forerunner Keep in touch with telecom related news, reports and data Analyze those information and try to figure out the trend of telecom development and rationale of carriers ’ investment strategies 2

News, Report, and Data Source: Information from Taiwan and foreign countries News: Yahoo Technology News, CommunicationDirect News, BBC Technology news Report: NCC, FCC, NTIA Data: Carrier ’ s website Blog: Cybertelecom blog, GigaOm, TeleFriden 3

Goals of This Class A clear picture in your mind to know about communications networks and basic components. After this course, you are enabled to identify different topologies of communication networks and explain their five components. 4

Outline of the Class Warm up Chapter 1 Introduction Q & A 5

Warm Up Any question? What are differences between communications & telecommunications 6

1-1 DATA COMMUNICATIONS Telecommunication is the assisted transmission of signals over a distance for the purpose of communications through electronic devices 電信法 : 指利用有線、無線，以光、電磁系統或其 他科技產品發送、傳 輸或接收符號、信號、文字、 影像、聲音或其他性質之訊息。 簡而言之 : 指利用電子技術在不同的地點之間傳遞 信息 Components Data Representation Data Flow Topics discussed in this section: 7

Figure 1.1 Five components of data communication 8

Figure 1.2 Data flow (simplex, half-duplex, and full-duplex) 9

1-2 NETWORKS A network is a set of devices (often referred to as nodes) connected by communication links. A node can be a computer, printer, or any other device capable of sending and/or receiving data generated by other nodes on the network. 10

1-2 Topics of Networks Distributed processing: Network Criteria: Physical Structures: Network Models: Categories of Networks: Interconnection of Networks: 11

1-2 Network Criteria Distributed processing: a task is divided among multiple computers. Instead of a large machine Network Criteria:  Performance: how good it is (throughput and delay)  Reliability:frequency of failure  Security: protecting data from unauthorized access, damage and change 12

1-2 Network Physical Structure & Categories Physical Structures:  P2P  P2MP Network Models: ISO’s OSI Categories of Networks:  LAN: local area network  WAN: wide area network  MAN: metropolitan area network Interconnection of Networks: Internetwork 13

Figure 1.3 Types of connections: point-to-point and multipoint 14

Figure 1.4 Categories of topology 15

Figure 1.5 A fully connected mesh topology (five devices) 16

Figure 1.6 A star topology connecting four stations 17

Figure 1.7 A bus topology connecting three stations 18

Figure 1.8 A ring topology connecting six stations 19

Figure 1.9 A hybrid topology: a star backbone with three bus networks 20

Figure 1.10 An isolated LAN connecting 12 computers to a hub in a closet 21

Figure 1.11 WANs: a switched WAN and a point-to-point WAN 22

Figure 1.12 A heterogeneous network made of four WANs and two LANs 23

1-3 THE INTERNET The Internet has revolutionized many aspects of our daily lives. It has affected the way we do business as well as the way we spend our leisure time. The Internet is a communication system that has brought a wealth of information to our fingertips and organized it for our use. 24

1-3 THE INTERNET BACKGROUND Why: Connect computers together to exploit valuable resources Where: from the US Who: DoD ARPA (ARPANET) When: mid-1960s What: IMP (interface message process) as communication device to connect four nodes together How: NCP (network control protocol) to Internetting Project to TCP/IP 25

Figure 1.13 Hierarchical organization of the Internet 26

1-4 PROTOCOLS AND STANDARDS In this section, we define two widely used terms: protocols and standards. First, we define protocol, which is synonymous with rule. Then we discuss standards, which are agreed-upon rules. 27

Homework 2 Type your answers in A4 size papers with your name Page 24: #4, #8, #9, #12, #13, #16 #17 Page 25: #21, #24 28

Thank you! Q & A 29