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Chapter 1 . Introduction to Telecommunications. Communication. 1. Process that allows information to pass between a sender and receiver - or - 2. Transfer of meaningful information between two locations Meaningful implies perception. Telecommunications. Tele means far off or distant
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Chapter 1 Introduction to Telecommunications
Communication 1. Process that allows information to pass between a sender and receiver - or - 2. Transfer of meaningful information between two locations • Meaningful implies perception
Telecommunications • Tele means far off or distant • Telecommunications today means communication by electrical or electromagnetic means, usually over a distance
Data Communications • Subset of telecommunications excluding analog signals • Non much analog these days
Data vs. Information • Data - representation of facts, concepts, etc. suitable for communication • Information - meaning associated with data
Telecommunications Elements • May have multiple transmitters in a system • Form networks • Rules or protocols • Example: establishing communications requires • Initiation • Identification of sender and receiver • Order of communication
Telecom and Business • Business must move data and voice information within locations and between locations • Timing • Information must be available when needed • Telecom advances are revolutionizing information transfer • Competitive business must maximize use of information for marketing and productivity enhancement • Transactions • Airline reservations, banking, marketing • Used for availability, location, shipping accounting • Online business: E-commerce
Telecom and Business • Reduces effect of geography • Link remote branches with voice/data/video • Mobile communications • Telecommuting
Telecom System Requirements (Data System) • Availability • System ready and operating when needed • Reliability • System trouble free and error free • Real time or real-enough time • Response time • System does not hinder user by introducing too much delay • Ease of use • Ergonomics • Flexibility and scalability • System easy to change to meet future needs
Availability • Variable requirements • Some applications need round-the-clock availability • Some businesses operate 8am to 5pm • Time zone effects • Must take into account working hours in other locations you must communicate with, nationally and internationally
Reliability • MTBF - mean time between failure • MTTR - Mean time to repair • How long does it take to repair system? • Reduce effects of failure with redundant (backup) components
Reliability Example 1 • Overall reliability in a cascaded system is always lower than the least reliable component
Key Telecom Events • 1847 - Telegraph • 1877 - Telephone • 1885 - American Telephone and Telegraph Company (AT&T) formed • 1895 - Radio • 1934 - Communications Act of 1934 (FCC) • 1939 - Television • 1947 - Microwave communications • 1956 - First transatlantic telephone cable TAT-1 • 1957 - Satellite • 1960s Computer/Terminal communications
Key Telecom Events • 1969 - ARPANET • An experimental data network • 1970 - Fiber optics • 1970s - Dial-up computer communications • 1978 - Cellular phone • 1981 - IBM PC • 1984 - AT&T Divestiture • 1980s - LAN • 1990 - World Wide Web (WWW) • 1996 - Telecommunications Act of 1996 • 1990s - Intranet, Extranet, E-Commerce, growth of wireless • Late 1990s - media convergence
Key Internet Events • 1961 - Leonard Kleinrock publishes paper on packet switching • 1969 - ARPANET test • 1970 - Network Control Protocol (NCP) implemented on ARPANET • 1971 - E-mail • 1974 - Kahn and Cerf publish paper on TCP/IP • 1974 - 62 hosts on ARPANET • 1979 - USENET newsgroup network
Key Internet Events • 1983 - Internet Activity Board (IAB) created to oversee protocol development • 1983 - TCP/IP version 4 adopted for ARPANET • 1983 - 500 hosts • 1984 - Domain Name System (DNS) • 1986 - National Science Foundation Network (NSFNET) • 1988 - Worm virus • 1988 - Computer Emergency Response Team (CERT) • 1990 - ARPANET retired
Key Internet Events • 1991 - Gopher menu-driven Intenet interface • 1991 - Tim Berners-Lee develops World Wide Web • 1992 - 1,000,000 hosts • 1993 - Mosaic graphical WWW interface • 1993 - Internet Network Information Center (InterNIC) • 1993 - 2,000,000 hosts • 1995 - NSF stops supporting NSFNET • Internet goes commercial • Internet Service Providers (ISPs)
Key Internet Events • 1995 - NSF starts supporting Very-High-Speed Backbone Network Service (vBNS) • 1996 - Telecommunications Act of 1996 • 1996 - 10,000,000 hosts • 1997 to present - E-commerce, distance learning, Voice-Over-IP, Virtual Private Networks, etc.
Major Internet Components • Backbone • Main infrastructure of Internet • Main nodes connected by T1, T3, OC3, OC12 links • Backbone routers • Packet switches route data • A DSU/CSU (Data Service Unit / Channel Service Unit) interfaces router to backbone • Internet Service Provider (ISP) • Company that links many users to backbone
Major Internet Components • Concentrator • Interfaces several network technologies in a single chassis • Similar to a router • Site Router • Also known as an Access Router or Premise Router • Connects a customer-s computers to the ISP
Major Internet Components • T. Fallon, The Internet Today, Upper Saddle River, NJ, Prentice Hall, 2000
Case Study - Dow Corning • Headquarters in Midland Michigan • Business • Develop, manufacture, and market silicones and related products • Business structure requires close coordination between marketing, manufacturing, etc. • Telecom at Dow Corning • Responsibility lies within corporate Information Technology (IT) department • Data and voice responsibilities brought under same group in 1982
Case Study - Dow Corning • Data and voice responsibilities brought under same group in 1982 • 1991 - emphasis on interaction between CIS department and telecom people in manufacturing areas • Network (in 1999) • 11,000 personal computers and terminals • 5,800 in U.S. • Goal to provide rapid response time for most transactions