Introduction to Introduction to Communications Communications

Part One: Overview Part One: Overview

Kuang Chiu HuangKuang Chiu HuangTCM NCKUTCM NCKU

Spring/2008Spring/2008

Information Forerunner 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

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News, Report, and Data 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

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Goals of This ClassGoals 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.

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

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Warm Up Warm Up • Any question?

• What are differences between communications & telecommunications

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1-1 DATA COMMUNICATIONS1-1 DATA COMMUNICATIONSTelecommunication 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

ComponentsData RepresentationData Flow

Topics discussed in this section:Topics discussed in this section:

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Figure 1.1 Five components of data communication

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

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1-2 NETWORKS1-2 NETWORKS

A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) connected by communication ) connected by communication linkslinks. A . A node can be a computer, printer, or any other node can be a computer, printer, or any other device capable of sending and/or receiving data device capable of sending and/or receiving data generated by other nodes on the networkgenerated by other nodes on the network ..

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1-2 Topics of Networks1-2 Topics of Networks

Distributed processing:Network Criteria: Physical Structures: Network Models: Categories of Networks: Interconnection of Networks:

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1-2 Network Criteria1-2 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

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1-2 Network Physical Structure & Categories1-2 Network Physical Structure & Categories

Physical Structures: P2PP2MP

Network Models: ISO’s OSI Categories of Networks:

LAN: local area network WAN: wide area network MAN: metropolitan area network

Interconnection of Networks: Internetwork

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

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Figure 1.4 Categories of topology

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Figure 1.5 A fully connected mesh topology (five devices)

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Figure 1.6 A star topology connecting four stations

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Figure 1.7 A bus topology connecting three stations

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Figure 1.8 A ring topology connecting six stations

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

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

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

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

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1-3 THE INTERNET1-3 THE INTERNET

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

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1-3 THE INTERNET BACKGROUND 1-3 THE INTERNET BACKGROUND

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

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Figure 1.13 Hierarchical organization of the Internet

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1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section, we define two widely used terms: In this section, we define two widely used terms: protocolsprotocols and and standardsstandards. First, we define protocol, which is . First, we define protocol, which is synonymous with rule. Then we discuss standards, which synonymous with rule. Then we discuss standards, which are agreed-upon rules.are agreed-upon rules.

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Homework 2Homework 2

Type your answers in A4 size papers with your name

• Page 24: #4, #8, #9, #12, #13, #16 #17

• Page 25: #21, #24

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Thank you!Thank you!

Q & A Q & A 29