Beekman5 std ppt_09


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Beekman5 std ppt_09

  1. 1. Chapter 9 Networking and Telecommunication
  2. 2. Topics <ul><li>Linking Up: Network Basics </li></ul><ul><li>Electronic Mail, Teleconferences, and Instant Messages: Interpersonal Computing </li></ul><ul><li>Converging Communication Technologies: From Messages to Money </li></ul>
  3. 3. Linking Up: Network Basics <ul><li>A computer network is any system of two or more computers that are linked together. </li></ul><ul><li>How do networks impact systems? </li></ul><ul><ul><li>People share computer hardware, thus reducing costs </li></ul></ul><ul><ul><li>People share data and software programs, thus increasing efficiency and production </li></ul></ul><ul><ul><li>People work together in ways that are otherwise difficult or impossible </li></ul></ul>
  4. 4. Basic Network Anatomy <ul><li>The three basic components of a network: </li></ul><ul><ul><li>Hardware </li></ul></ul><ul><ul><li>Software </li></ul></ul><ul><ul><li>People </li></ul></ul><ul><li>Direct Connection--one of many computers linked in an office </li></ul><ul><li>Remote Access--computer linked to a network through a phone line, television cable system or satellite link </li></ul>
  5. 5. The Network Interface <ul><li>A network interface card (NIC) permits direct network connection </li></ul><ul><li>It adds an additional serial port to the computer </li></ul><ul><li>The network interface card controls the flow of data between the computer’s RAM and the network cable. </li></ul>
  6. 6. Communication á la Modem <ul><li>A modem is a hardware device that connects a computer’s serial port to a telephone line (for remote access). </li></ul><ul><li>May be internal on the system board or external modem sitting in a box linked to a serial port. </li></ul><ul><li>Modem transmission speed is measured in bits per second (bps) and generally transmit at 28,000 bps to 56.6K bps </li></ul>
  7. 7. Conversion of Signals Computers send digital signals. The modem (modulator/ demodulator) converts the digital signals to analog so that the message can be transmitted through telephone lines.
  8. 8. Conversion of Signals The modem (modulator/demodulator) converts the analog signals back to digital signals that are understood by the computer
  9. 9. Networks Near and Far <ul><li>Local-area network (LAN) </li></ul><ul><ul><li>Computers are linked within a building or cluster of buildings. </li></ul></ul><ul><ul><li>Each computer and peripheral is an individual node on the network. </li></ul></ul><ul><ul><li>Nodes are connected by cables which may be either twisted pair (copper wires) or coaxial cable. </li></ul></ul>
  10. 10. Networks Near and Far <ul><li>Wide-area network (WAN) </li></ul><ul><ul><li>A network that extends over a long distance. </li></ul></ul><ul><ul><li>Each network site is a node on the network. </li></ul></ul><ul><ul><li>Data transmitted over common pathways called a backbone . </li></ul></ul>
  11. 11. Wide-Area Networks <ul><li>Made up of LANs linked by phone lines, microwave towers, and communication satellites. </li></ul><ul><li>Bridges, routers, and gateways are hardware devices that pass messages between networks. </li></ul>
  12. 12. Communication Software <ul><li>Protocol - set of rules for the exchange of data between a terminal and a computer or between two computers </li></ul><ul><li>Communication software establishes a protocol that is followed by the computer’s hardware </li></ul>
  13. 13. Communication Software <ul><li>Many forms: </li></ul><ul><ul><li>Network operating system (NOS) - handles communications between many workstations </li></ul></ul><ul><ul><li>Client/server model - one or more computers act as dedicated serves and all the remaining computers act as clients </li></ul></ul><ul><ul><li>Peer-to-peer model - every computer on the network is both client and server </li></ul></ul><ul><ul><li>Many networks are hybrids , using features of the client/server and peer-to-peer models </li></ul></ul>
  14. 14. Client/Server Model Client software sends requests from the user to the server Server software responds to client requests by providing data
  15. 15. The Network Advantage <ul><li>Why do people use networks? </li></ul><ul><ul><li>To share computer resources (hardware and software) </li></ul></ul><ul><ul><li>To support working together in new and different ways </li></ul></ul>Lotus Notes is a groupware application that facilitates information sharing and workgroup collaboration.
  16. 16. E-mail Mail, Teleconferences, and IM: Interpersonal Computing <ul><li>Electronic mail, teleconferencing and instant messaging allow communications between two or more people. </li></ul><ul><li>Meetings can be held in real-time (synchronous) or delayed (asynchronous) </li></ul><ul><li>Chat rooms are examples of synchronous communications; bulletin boards are examples of asynchronous communications. </li></ul>
  17. 17. The Postal Alternative <ul><li>E-mail is fast. </li></ul><ul><li>E-mail doesn’t depend on location. </li></ul><ul><li>E-mail facilitates group communication. </li></ul><ul><li>E-mail messages are digital data that can be edited and combined with other computer-generated documents. </li></ul>
  18. 18. Advantages of E-mail and Teleconferencing <ul><li>On-line communication is less intrusive. </li></ul><ul><li>On-line communication allows time shifting. </li></ul><ul><li>Teleconferences and e-mail promotes teleworking. </li></ul><ul><li>Teleconferences and e-mail emphasize the message over the messenger. </li></ul>
  19. 19. On-line Issues for E-mail and Teleconferencing <ul><li>Vulnerable to machine failures, network glitches, human errors and security </li></ul><ul><li>Threat to privacy </li></ul><ul><li>E-mail forgery </li></ul><ul><li>Information overload </li></ul><ul><li>Missing “human” elements of communication </li></ul>
  20. 20. Rules of Thumb: On-line Survival Tips <ul><li>If you don’t have to be on line, go off line. </li></ul><ul><li>Avoid peak hours </li></ul><ul><li>Let your system do as much of the work as possible. </li></ul><ul><li>Store names and addresses in an on-line address book </li></ul><ul><li>Protect your privacy </li></ul><ul><li>Cross-check on-line information sources </li></ul><ul><li>Be aware and awake </li></ul><ul><li>Avoid information overload. </li></ul>
  21. 21. Converging Communication Technologies: From Messages to Money <ul><li>On-line Information Services </li></ul><ul><li>Fax Machines and Fax Modem </li></ul><ul><li>Voice Mail and Computer Telephony </li></ul><ul><li>Global Positioning System </li></ul><ul><li>Video Teleconferencing </li></ul><ul><li>E-Money </li></ul>
  22. 22. Physical Media for Networks <ul><li>Networks are built on physical media. </li></ul><ul><ul><li>Twisted pair (Category 5) </li></ul></ul><ul><ul><li>Twisted pair (Traditional) </li></ul></ul><ul><ul><li>Coaxial Cable </li></ul></ul><ul><ul><li>Fiber optic </li></ul></ul><ul><ul><li>Wireless/infrared </li></ul></ul><ul><ul><li>Wireless/radio </li></ul></ul><ul><li>What affects network performance? </li></ul><ul><ul><li>Bandwidth and maximum operating distance </li></ul></ul>“ Never in history has distance meant less.” Alvin Toffler
  23. 23. Bandwidth <ul><li>The amount of information that can be transmitted in a given amount of time </li></ul><ul><li>Impacted by: </li></ul><ul><ul><li>Physical media that make up the network </li></ul></ul><ul><ul><li>Amount of network traffic </li></ul></ul><ul><ul><li>Software protocols of the network </li></ul></ul><ul><ul><li>Type of network connection </li></ul></ul>
  24. 24. Fiber Optic Cables <ul><li>Fiber optic cables are replacing aging cooper lines with high-capacity fiber optic cables. </li></ul><ul><li>They use light waves to carry information at blinding speeds. </li></ul><ul><li>A single fiber optic cable can transmit half a gigabit (500 million bits) per second, replacing 10,000 standard telephone cables. </li></ul><ul><li>Data is transmitted more accurately and reliably. </li></ul>
  25. 25. Digital Communication Comes Home <ul><li>Digital communication lines will radically change services to our homes. </li></ul><ul><li>Multi-person video phone conversations, universal e-mail, customized digital newspapers, automatic utility metering and unlimited entertainment options </li></ul>