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8. TELECOMMUNICATIONS AND NETWORKS

8. TELECOMMUNICATIONS AND NETWORKS. LEARNING OBJECTIVES. Components of Telecommunications System Calculate Capacity of Telecommunications Channels & Evaluate Transmission Media Types of Networks & Network Services *. 8.2. LEARNING OBJECTIVES. Describe connectivity network standards

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8. TELECOMMUNICATIONS AND NETWORKS

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  1. 8. TELECOMMUNICATIONS AND NETWORKS

  2. LEARNING OBJECTIVES • Components of Telecommunications System • Calculate Capacity of Telecommunications Channels & Evaluate Transmission Media • Types of Networks & Network Services * 8.2

  3. LEARNING OBJECTIVES • Describe connectivity network standards • Identify applications for supporting electronic commerce, business • Analyze management problems of networking * 8.3

  4. Communication Theories Sender -> medium -> receiver Coding -> transmit -> decoding * 8.4

  5. INFORMATION SUPERHIGHWAY • Is this a good analogy? • Look for analogies of business development after railroad, interstate highways, and telephone. *

  6. SYSTEM COMPONENTS • Computers • Terminals (Input/Output Devices) • Communication channels (medium) • Processors (Modems; Multiplexers; Front-end Processors) • Network software *

  7. Dictionaries and Protocols • Dictionary: code conversion • Protocol: rules and procedures used for transmission *

  8. ANALOG SIGNAL • Continuous waveform • Voice Communications *

  9. DIGITAL SIGNAL • Discrete waveform • Two discrete states: • 1-bit & 0-bit • ON / OFF pulse • The meaning of 32-bit, 64-bit, etc. • Data Communications *

  10. Sampling • Converting analog signals to digital signals • Increased flexibility for editing • Smaller codes (.wav vs. .mid files)

  11. COMMUNICATION CHANNELS Means by which data are transmitted: • Twisted pair(Copper Wires) • Coaxial cable:(Insulated Copper Wires) • Fiber-optic cable • Microwave *

  12. SIGNAL LASER CABLE PHOTO DETECTOR SIGNAL FIBER OPTICS • Super clear glass strands • High bandwidth (up to ten billion bits per second transmission) • Full duplex (two-way communication) *

  13. LOW-ORBIT SATELLITE MICROWAVE TRANSMISSION UPLINK DOWNLINK

  14. WIRELESS TRANSMISSION TECHNOLOGIES • PAGING SYSTEM:Small Page Beeps when Receives Short Message • CELLULAR TELEPHONE:Device uses Radio Waves to Reach Antennas Within Areas Called Cells • MOBILE DATA NETWORKS:Radio - based Data Network using Hand-held Computers. Cheap, Efficient *

  15. WIRELESS TRANSMISSION TECHNOLOGIES • Personal Communication Service:Cellular; Lower Power; Higher Frequency. Smaller Phones not Shielded by Buildings, Tunnels • Personal Digital Assistant:Pen Sized, Hand-held, Digital Communicator *

  16. Communication Channels are evaluated by: • Transmission Speed:Bits per Second (BPS) or Baud • Bandwidth:Capacity of Channel; Difference between Highest & Lowest Frequencies *

  17. SPEEDS & COST OF MEDIA MEDIUM SPEED COST TWISTED PAIR 300 BPS - 10 MBPS LOW MICROWAVE 256 KBPS - 100 MBPS SATELLITE 256 KBPS - 100 MBPS COAXIAL CABLE 56 KBPS - 200 MBPS FIBER OPTICS 56 KBPS - 10 GBPS HIGH BPS: BITS PER SECOND KBPS: KILOBITS PER SECOND MBPS: MEGABITS PER SECOND GBPS: GIGABITS PER SECOND 8.18

  18. COMMUNICATIONS PROCESSORS • FRONT- END PROCESSOR:minicomputer manages communication for host computer (secretary) • CONCENTRATOR:computer collects messages for batch transmission to host computer • CONTROLLER:computer controls interface between CPU and peripheral devices (traffic cop) • MULTIPLEXER:allows channel to carry multiple sources simultaneously *

  19. USER USER HOST USER USER Network Topologieshow computers are tied together STAR

  20. USER USER USER USER USER USER Network Topologieshow computers are tied together BUS (“Broadcast”)

  21. USER USER USER USER Network Topologieshow computers are tied together RING

  22. Types of Local Networks • Private Branch Exchange (PBX):firm’s central switching system • Local Area Network (LAN):dedicated channels; limited distance; higher capacity than PBX. Can share expensive hardware & software *

  23. Local Area Network • Server:stores programs, data; determines access to network • Gateway:connection to other networks • Network Operating System (NOS):manages file server; routes communications on network • Peer-to-peer vs. Client/Server *

  24. Wide Area Network (WAN) • Spans large geographic distances • Can include cable, satellite, microwave *

  25. Dedicated Line vs. Shared Line • Cost and benefit of a dedicated line • Additional arrangements (overhead) needed for people to share the same medium

  26. NETWORK SERVICES • Packet Switching (delivered bits and pieces) • Frame Relay (delivered in chunks) • Asynchronous Transfer Mode (ATM) • Integrated Services Digital Network (ISDN) • Digital Subscriber Line (DSL) • Cable modem • T1 Line (high capacity phone line) *

  27. PACKET SWITCHING (X.25): • Breaks data blocks into small packets (e.g.: 128 Bytes) • Packets routed via the most economical means • Reassembled at destination *

  28. TCP/IP Model Components Developed by Dept of Defense in 1972 • Application Layer • Transmission Control Protocol (TCP): Breaks Data into Datagrams • Internet Protocol (IP): Breaks, Sends Datagrams as Smaller IP Packets; Can Repeat Transmission to Increase Reliability * 8.35

  29. TCP/IP Model Components • NETWORK INTERFACE: Handles Addressing and Interface Between Computer & Network • PHYSICAL NET: Defines Electrical Transmission Characteristics for Sending Signal Along Networks to Destination * 8.36

  30. OPEN SYSTEM INTERCONNECT (OSI) INTERNATIONAL REFERENCE MODEL FOR LINKING DIFFERENT TYPES OF COMPUTERS & NETWORKS. LAYERS: 1. PHYSICAL: Transmission of Data over Medium 2. DATA LINK: Packaging, Transfer of Packets; Error Checking 3. NETWORK: Routing Packets Over WAN *

  31. OPEN SYSTEM INTERCONNECT (OSI) 4. TRANSPORT: Ensures Reliable Data Delivery 5. SESSION: Establishes Communication Links on Network 6. PRESENTATION: Code Conversion for Data Presentation 7. APPLICATION: Specialized User Functions (e.g.: Operating System; File Transfer; e-mail) *

  32. FACILITATING APPLICATIONS • E-mail • Voice mail • Fax • Teleconferencing • Dataconferencing • Videoconferencing • Groupware *

  33. Groupware:for collaborative works • Group writing and commenting • Email distribution • Scheduling • File/Database sharing • E-meetings *

  34. DIGITAL INFORMATIONSERVICES PROVIDER TYPE OF SERVICE AMERICA ONLINE GENERAL INTEREST / BUSINESS INFORMATION COMPUSERVE GENERAL INTEREST / BUSINESS INFORMATION PRODIGY GENERAL INTEREST / BUSINESS INFORMATION DOW JONES NEWS RETRIEVAL BUSINESS / FINANCIAL INFORMATION QUOTRON FINANCIAL INFORMATION DIALOG BUSINESS / SCIENTIFIC / TECHNICAL INFORMATION LEXIS LEGAL RESEARCH NEXIS NEWS / BUSINESS INFORMATION

  35. SELLER CUSTOMER ORDERS, PAYMENTS COMPUTER COMPUTER SHIPPING NOTICES, PRICE UPDATES, INVOICES Electronic Data Interchange (EDI) Computer-to-computer Exchange between two organizations of standard business transaction documents *

  36. MANAGEMENT ISSUES & DECISIONSPROBLEMS: • CONNECTIVITY • LOSS OF MANAGEMENT CONTROL • ORGANIZATIONAL CHANGE REQUIREMENTS • HIDDEN COSTS OF CLIENT/SERVER COMPUTING • RELIABILITY & SECURITY *

  37. MANAGEMENT ISSUES & DECISIONS TELECOMMUNICATIONS PLAN: • KNOW LONG-RANGE PLANS • AUDIT EXISTING CAPABILITIES • IDENTIFY, PRIORITIZE CRITICAL IMPROVEMENTS • ENHANCE FIRM’S STRATEGIC POSITION IMPLEMENT PLAN *

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