Introduction to Data Communications and Computer Networks Surasak - - PDF document

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1/20 Applied Network Research Group Department of Computer Engineering, Kasetsart University

Introduction to Data Communications and Computer Networks

Surasak Sanguanpong nguan@ku.ac.th http://www.cpe.ku.ac.th/~nguan

Last updated: 2 November 2004 2/20 Applied Network Research Group Department of Computer Engineering, Kasetsart University

Outline

• Data Communications
• Communications Networks
• Standards
• Standards Organizations

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What is data communications?

• Telecommunications : literally means communication
• ver a distance. All type of communications such as

telephone, data (computers), cable television, and wireless communications have converged under the umbrella of the telecommunications field

• Data communications is the subset of

telecommunications that involves the transmission and reception of data to and from computers and components

• f computer systems

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Communication Tasks

Error detection Error correction Recovery Protection Interfacing Signal generation Message formatting Transmission system

utilization

Exchange management System management Addressing Flow control Routing

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A Communications Model

input information

Communications system

Source system Destination system

Source Device Source Device Transmitter Transmitter Transmission medium Transmission medium Receiver Receiver Destination device Destination device

input data transmitted signal received signal

• utput data
• utput information

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A Communications Example

Telephone Networks

Source system Destination system

A 110011 110011 A

computer modem modem computer

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Communications Networks

Local Area Network (LAN) Local Area Network (LAN) Metropolitan Area Network (MAN) Metropolitan Area Network (MAN) Wide Area Network (WAN) Wide Area Network (WAN) Categories of Networks Categories of Networks

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LAN

hub/switch hub/switch hub/switch hub/switch router

General Characteristics :

Confined geographical area Under single management High data rate

servers stations stations stations

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MAN

Public city network LAN LAN LAN LAN

• A network which cover an entire city
• A single network or a number of

connected LANs

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WAN

• A network that cover a relatively broad geographic area
• It often uses long-distance transmission facilities provided

by public carriers

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Internetwork

LAN LAN LAN LAN MAN WAN LAN

• Collection of networks interconnected by routers and other

devices

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Communications System

Frame Relay Network ATM Network ISDN Network

Internet

• New generation of switching technologies provide improved

services to home and workplace

E/T-carrier Leased Line Cable Modem ADSL CATV PSTN Network Modem

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Standards

• Standards without any

formal plan De facto De facto De jure De jure Standards Standards

• Formal, legal standards adopted by

some authorized standardization body

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Standards Organizations

IEEE ANSI EIA ITU-T ISO IETF

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ITU-T

• International standard
• rganization that

develops standard for telecommunications

• Some well known

standards

• V series
• X series
• H series
• G Series
• International Telecommunications Union-

Telecommunication Standard Sector

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ISO

• An International

standard organization that develops standard for variety of fields

• International Standards Organization

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IETF

• a large open international

community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture

Internet Engineering Task Force 18/20 Applied Network Research Group Department of Computer Engineering, Kasetsart University

IEEE

• The largest professional

group involved in standards for computing, communications, electrical and electronics

• Institute of Electrical and Electronics Engineers

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ANSI

• U.S. nonprofit
• rganization
• American National Standard Institute

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EIA

• A nonprofit organization

devoted to the promotion of electronics manufacturing

• Electronic Industries Alliance