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Introduction to Networks and Telecommunications: Sharing Data, Teamwork, and Communication

This chapter provides an introduction to networks and telecommunications, focusing on sharing data, collaboration through teamwork, and effective communication. It covers various components of a network, network structure, internet, and technical and cultural challenges. The chapter also includes case studies and an appendix on creating web pages.

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Introduction to Networks and Telecommunications: Sharing Data, Teamwork, and Communication

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  1. Introduction to MIS Chapter 3 Networks and Telecommunications

  2. Networks Internal Teamwork Communication Scheduling Sharing Internet External Suppliers Customers Banks

  3. Introduction Sharing Data Sharing Hardware Sharing Software Components of a Network Computers Media Connection Devices Software Network Structure Shared Media Switched Standards The Internet How the Internet Works Internet 2 Mobile Commerce Global Telecommunications Technical Problems Political Complications Cultural Issues Comment Cases: Specialty Retail Appendix: Creating Web Pages Outline

  4. Sharing Data: Transactions Internet Database Management System and Web Server

  5. Decisions & searches Teamwork & joint authorship Team Document Sharing Data: Decisions & Searches File Server and Database Data and Tools Report and Comments

  6. Sharing Data: E-mail Internet 2. Message transferred to account on server. 3. Transferred via the Internet to the destination account. 4. Message received when user checks e-mail. 1. User creates e-mail message.

  7. Sharing Data: Calendars 8:00 Mgt meeting 8:30 (open) 9:00 Staff meeting 9:30 Staff meeting 10:00 new meeting

  8. Printers Storage Processors Files are transferred from workstations to the server. Software automatically copies files to tapes. LAN administrator can restore files if needed. Hardware Sharing tape drive (backup) Corporate or external computer access Workstations Shared Printer Server

  9. Packet-Switched Networks • Data, Voice, Video • All converted to packets • Packet has data, destination, and source address • Switched services • Packets routed as needed • Reassembled at destination Sent as packets: 1 2 3 4 5 Voice B 2 Chicago New York C A 4 1 E Atlanta Dallas 3 D 5 Sent as packets: A B C D E Computer

  10. Computers Servers Work stations Media Cables Fiber optic Radio Infrared Connection devices Network Components Personal Computer Personal Computer LAN card LAN card Internet LAN card LAN card Router or Switch Firewall Shared Printer Server

  11. Server Scalability Server farms distribute the workload. Add more computers for more power. Sun 10000 Increasing performance within a product family. Sun 3800 Rack mount server farm. Compaq Sun Ultra 5

  12. Electricity Fiber optics Radio waves Network Transmission Media Fiber Optic Cable Example: Long distance phone lines reflective cladding Twisted Pair Example: Local phone lines glass or plastic Radio or Micro Waves Example: Cellular phones Coaxial Example: Cable TV antenna Shield

  13. Faster More data Less magnetic interference Long stretches without repeaters Fiber Optics 900 copper wires can be replaced by one fiber optic line (for telephone connections).

  14. All waves behave similarly Sound Radio Micro Light Frequency differences Amount of data Distance Interference / Noise Frequency Spectrum http://www.jsc.mil/images/speccht.jpg AM: 550K - 1650 KHz TV: 54M - 216 MHz TV: 220M - 500 MHz FM: 88M - 108 MHz Navy/submarines ELF VLF LF MF HF VHF UHF Microwave Optical Hertz 100 1K 100K 1M 10M 100M 1G 10G Public Safety: 150M - 160 MHz Public Safety: 460M - 500 MHz Cordless phones (some): 900 MHz Cellular phones: 800 MHz PCS ET: 2 GHz Pers. Com. Sys (PCS): 1.85 G - 2.2 GHz http://www.ntia.doc.gov/osmhome/allochrt.pdf

  15. Transmission Capacity A thin fiber optic cable can carry as much data as 900 single copper wires, with minimal interference, and superior tensile strength.

  16. The Importance of Bandwidth

  17. Shared Connections With shared connections, machines have to take turns, and congestion can slow down all connections. With switched connections, each computer has the full bandwidth of the connection at all times. Performance depends on how fast the switch can handle connections.

  18. Time Division A B A C A C A time C D Computers A and B split their messages into packets and share the transmission medium by taking turns sending the data.

  19. Frequency Division A B frequency A 3500 Hz C C D Computers A and B split the frequency: A uses a higher spectrum. By listening only to the assigned frequency, multiple transmissions can occur at the same time.

  20. Spread Spectrum frequency A B C D time Sharing a medium by both frequency and time is one method of spread spectrum transmission. It is efficient for many computers because the full bandwidth can be utilized over time and frequency.

  21. WirelessCommunication Microwave transmissions are used to provide communications for cellular phones and laptop computers. As prices of phones, portable computers, and communication costs decrease, increasing numbers of workers are choosing wireless technologies.

  22. The need for standards A changing environment Connecting Networks Internet Backbone fiber optic Routers or Switches Switch Hub Hub Radio-based network

  23. Shared-Media Network Shared Media Tap

  24. Switched Network Switch Servers Workstations/PCs

  25. Switch Servers Workstations/PCs Enterprise Network Building 1 Building 2 Fiber optic Firewall Internet – ISP Subsidiary

  26. TCP/IP Reference Model 4. Application 3. Transport (TCP) 2. Internet (IP) 1. Physical Message Header 3 Message Trailer 3 Header 2 Header 3 Header 3 Message Message Trailer 3 Trailer 3 Trailer 2 Header 1 Header 2 Header 3 Header 3 Message Message Trailer 3 Trailer 3 Trailer 2 Trailer 1

  27. TCP/IP Reference • Application • Mail, Web, FTP • Authentication, compression, user services • Transport • Packetize data and handle lost packets • Establish connections through numbered ports • Internet Protocol (IP) • Route packets to destination • Requires unique host addresses: IPv4=32-bit; IPv6=128-bit • Requires standards and cooperation • Subnet • Physical connections • Transfers bits with some form of error correction

  28. Introduction to the Internet • No control • Services • Mail • Telnet • FTP • WWW • WEB searching • AltaVista • HotBot • Lycos • WebCrawler • Yahoo The Internet

  29. How the Internet Works Network service provider (NSP) OC3: 155.52 Mbps OC12: 622 Mbps T1: 1.544 Mbps T3: 44.736 Mbps Backbone network Internet service provider (ISP) Phone company Phone company Cable company Dial-up: 33.3 - 56 Kbps ISDN: 128 Kbps DSL: 256 Kbps - 6 Mbps Cable: 1 to 10 Mbps Company Web site Individual

  30. Backbone providers AT&T GTE Worldcom/MCI Sprint Qwest Network service providers 1998: 39 AGIS AT&T Cable & Wireless IBM MCI/Worldcom Qwest Sprint UUNet Phone companies Regional Bell operating companies (RBOCs) (6) Competitive local exchange carriers (CLECs) (new) Cable companies AT&T Cablevision Regional. Satellite Direct Satellite Starband Internet service providers America Online Microsoft Network Earthlink Internet Connections

  31. M-Commerce Internet access everywhere Cell phones PDAs Laptops Great potential Limited usability Better than voice?

  32. Cell Phones and Wireless Communication Wireless cells work by handing off the wireless connection to the next tower as the caller moves. Connections to multiple towers at one time enables the system to triangulate to get a fairly precise location of the cellular device--even when it is not in a call. Location knowledge will make it possible (although perhaps not desirable) to offer new business opportunities as people move into range.

  33. Technical problems Multiple standards Language Developing nations Time zones Limits to space & waves Political complications Transborder data flows Taxes Privacy Accessibility Cultural issues What is an object? Management & control Global Telecommunications

  34. Cases: Specialty Retail

  35. Cases: Ben & Jerry’s

  36. Determine the content. Define a style. Create each page. Text Graphics Link the pages. Test your work. Transfer pages to a Web site. Appendix: Creating Web Pages

  37. Appendix: Style Sheets BODY { margin-left: 5px; font: 10pt "Times New Roman", Times, serif; color: black; text-align: left; background-color: #e0ffff; } P { margin-left: 0px; font: 10pt "Times New Roman", Times, serif; color: black; background: transparent; } H1 { margin-left: 0px; font: 16pt "Times New Roman", Times, serif; color: black; font-weight: bold; background: transparent; } Style Sheet Body { … } P {…} Page 3 Page 2 Page1

  38. Appendix: Sample HTML <HTML> <HEAD> <TITLE>Sample HTML Page</TITLE> </HEAD> <BODY> <H1>Section One</H1> <P>This is a sample paragraph on a sample page.</P> </BODY> </HTML>

  39. Appendix: Publishing Files Accessible Web pages Internet or intranet Initial pages Web server Transfer methods: Microsoft Front Page extensions FTP: file transfer protocol Your computer

  40. Start with a tool like Microsoft Word (or Front Page, etc.). Get a good graphics package Keep page size small 30,000 - 50,000 bytes typically takes 8 - 15 seconds First develop the pages on your own computer. Test all links. Transfer later. Use style sheets. Consistency. Ease of change. Study design elements and art. Formal training/art classes. Study other sites. Watch for and create trends. Web Development Hints

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