business data communications, fourth edition chapter 1: introduction to communications
TRANSCRIPT
Business Data Communications, Fourth Edition
Chapter 1: Introduction to Communications
Learning Objectives
• Define data communications• Describe the difference between data
communications and telecommunications• Define local area networks, wide area
networks, metropolitan area networks, wireless networks, and personal area networks
• Understand the components of a communications system
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Learning Objectives
• Describe the role of, and list, regulatory agencies in data communications
• List the standards-setting organizations involved in the communications industry
• Explain how the government uses communications networks
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Introduction
• Communications began from primitive methods
• More efficient communications were needed with the advance of the industrial age
• The telegraph began the age of electronic communications
• Voice, video, and data transmitted in modern communications systems
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What is Data Communications?
• Transmission of data over a network• Subset of telecommunications• Networks
– Telephone system– May connect computers and related devices– PC prices have dropped – Data communications network
• Computers and related devices• Devices and lines used to connect the devices
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What is Data Communications?
• Networks– Types of networks
• Wide area network (WAN)• Local area network (LAN)• Metropolitan area network (MAN)• Internet• Wireless networks• Personal Area Network (PAN)
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Basic Components of a Communications System
– Three physical components• Source (or sender)• Medium• Receiver
– One Software component• Protocol
– Circuit– Example – Drive-up bank window
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The Telephone System
• Telegraph – 1840
• Telephone – 1876
• AT&T was a monopoly– Positive aspects of standardization
• Divestiture in 1984
• Data communications and the telephone system
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The Telephone System
• Common Carriers– Profit-oriented companies– Over 1200 in the United States– Cellular service providers– Local and long distance service
• IntraLATA Calls– Local Access Transport Areas (LATAs)– Local and “local long distance”
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The Telephone System
• InterLATA Calls– Long distance calls– May or may not use a carrier different from
the one offering local telephone service– Divestiture has allowed all companies to
compete in both local and long distance markets
– Slamming – unauthorized switch to a different phone company
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Governmental and Regulatory Agencies
• Federal Communications Commission (FCC)– Created in 1934– Prior to that time, the Interstate Commerce
Commission controlled communications– Regulates interstate and international
telecommunications– Tariff schedules
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Governmental and Regulatory Agencies
• Public Utility Commissions– Regulate intrastate communications– Regulate common carriers within a state– Rates charged can differ by state– Negotiates when conflicts arise, if the problem
is completely within a single state
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Governmental and Regulatory Agencies
• National Telecommunications and Information Administration (NTIA)– Branch of the U.S. Department of Commerce– Catalyst for innovation in communications
industry– Helps create jobs in that sector– Establishes grants to create a
communications infrastructure for all citizens
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Standards Organizations
• American National Standards Institute (ANSI) – Creates voluntary national standards– Has over 1,000 members– Works to create consensus on standards
among all the groups– Publishes standards created by other
organizations– Creating a standard for FDDI
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Standards Organizations
• International Organization for Standardization (ISO)– Non-electronic telecommunication standards– Created the Open Systems Interconnection
(OSI) 7-layer model
• Corporation for Open Systems– Promotes the use of equipment that meets
ISO standards
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Standards Organizations
• International Telecommunication Union (ITU)– Equipment standards in other countries– Provides technical assistance in setting up
communications systems in third world countries• International Telecommunication Union-
Telecommunication Standardization Sector (ITU-T)– Fosters cooperative standards for
telecommunications equipment and systems– Took over functions of the CCITT
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Standards Organizations
• Institute of Electrical and Electronics Engineers (IEEE)– An ANSI member organization– Standards developed for the lowest two levels
of the OSI model– Developed standards for local area networks
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Standards Organizations
• Electronics Industries Association (EIA)– Sets electrical standards– Members are manufacturers of electrical equipment– Developed standards for the lowest level of the OSI
model• Telecommunications Industry Assn. (TIA)
– Members are companies that provide communications and other IT products and services
– Acts as a voice on public policy and international matters that affect its members
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Standards Organizations
• Committee T1– Provides standards for interfaces– Accredited by ANSI– Addresses issues related to interconnection of
customers to public communications carriers
• Personal Communications Industry Association (PCIA)– Trade association for the personal communications
services industry– Regulations and standards related to wireless
communications
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Standards Organizations
• Cellular Telecommunications Industry Association (CTIA)– Conducts surveys on use of cellular technology
• Communications Satellite Corporation (COMSAT)– Coordinates use of satellites among countries, and
represents the USA
• International Telecommunications Satellite Organization (INTELSAT)– Coordinates use of satellites internationally
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Applications of Data Communications
• Computer system processing– Early systems
• Batch• No networks
– Modern systems • On-line• Networks
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Applications of Data Communications
• Government Applications– Original use – Census data collection in 1950– Internal Revenue Service (IRS)– National Aeronautical and Space
Administration (NASA)– Military uses
• The Internet– E-Commerce
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Chapter Summary
• Rapid increase in communications
• Data transmission
• Three components of communications
• Common carriers
• FCC and PUCs
• Regulatory agencies
• Common uses for communications networks
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Chapter 1 Complete