Networking and Telecommunications 9

 2001 Prentice Hall9.2 Chapter Outline Linking Up: Network Basics Electronic Mail, Teleconferences, and Instant Messages: Interpersonal Computing Converging Communication Technologies : From Messages to Money “Any sufficiently advanced technology is indistinguishable from magic.” Arthur C. Clarke

 2001 Prentice Hall9.3 Linking Up: Network Basics Cost –allows people to share hardware Efficiency & Productivity –allows people to share data and software Opportunity –allows people to work together in ways that are otherwise difficult or impossible Why is networking important?

 2001 Prentice Hall9.4 Basic Network Anatomy A computer network is any computer system that links two or more computers There are three essential components in a network: –Hardware –Software –People

 2001 Prentice Hall9.5 The Network Interface A Network Interface Card (NIC): –Is needed to connect directly to a network –Adds an additional port to the computer –Controls the flow of data between the computer’s RAM and the network cable –Converts the computer’s digital signals into the type required for the particular network

 2001 Prentice Hall9.6 A modem is needed to connect a computer to a phone line Communication á la Modem The computer communicates with digital signals The telephone system was designed to transmit voice signals, which are analog

 2001 Prentice Hall9.7 The word modem comes from the terms modulation and demodulation How a Modem Works Modulation Demodulation

 2001 Prentice Hall9.8 A modem: –Converts the digital stream of information from a computer to an analog stream in order to send a message on the telephone network Communication á la Modem

 2001 Prentice Hall9.9 A modem: –Converts the analog stream of information received over the telephone network into the digital form that the computer understands Communication á la Modem

 2001 Prentice Hall9.10 WAN (Wide Area Network) LAN (Local Area Network) Networks Near and Far There are two general types of computer networks:

 2001 Prentice Hall9.11 LAN (Local Area Network) A LAN is a network in which the computers are physically close to each other –They typically share peripherals (printers and servers) –Each computer and shared peripheral is a node on the LAN

 2001 Prentice Hall9.12 A WAN is a network in which the computers are a great distance from one another WAN (Wide Area Network) –Connections are made via telephone lines, satellites, and/or microwave relay towers –Each network site is a node

 2001 Prentice Hall9.13 WAN (Wide Area Network) WANs are often made up of LANs

 2001 Prentice Hall9.14 Communication software includes: Communication Software –Software that allows the hardware to interact with various networks –A network operating system (NOS) which controls information shared between the dedicated server and client machines

 2001 Prentice Hall9.15 Client/Server Model Client software sends requests from the user to the server Server software responds to client requests by providing data

 2001 Prentice Hall9.16 The peer-to-peer model allows every computer on the network to be both client and server Peer-to-Peer Model Peer-to-peer networking is built into some operating systems Many networks use a hybrid of client/server and peer-to-peer

 2001 Prentice Hall9.17 The Network Advantage Networks allow people to: –Share computer resources (hardware and software) –Share data –Work together in new ways

 2001 Prentice Hall9.18 , Teleconferences, & IM: Interpersonal Computing Electronic mail, teleconferencing, and Instant messaging (IM) allow communication between two or more computer users People can communicate in real time or delayed time

 2001 Prentice Hall9.19 Real-Time vs. Delayed Communication Real-time communication (synchronous): –participants meet in real time –participants see each other’s typed messages as they are typed –examples: Talk and Chat

 2001 Prentice Hall9.20 Real-Time vs. Delayed Communication Delayed communication (asynchronous): –Participants type, post, and read messages at their convenience –Participants share an electronic mailbox related to the group’s purpose –Examples: and Newsgroups

 2001 Prentice Hall9.21 The Postal Alternative Speed Accessibility Facilitates group communication Allows messages to be edited and combined with other documents Less intrusive than the telephone

 2001 Prentice Hall9.22 Advantages of and Video/Teleconferencing Allows decisions to evolve over time Emphasizes the message, not the messenger Makes long-distance meetings possible through video and tele- conferencing

 2001 Prentice Hall9.23 Disadvantages of and Teleconferencing Vulnerable to machine errors, human errors, and security breaches Can pose a threat to privacy Can be faked

 2001 Prentice Hall9.24 Disadvantages of and Teleconferencing Works only if the recipient responds Can be overwhelming Both filter out many human components of communication

 2001 Prentice Hall9.25 Rules of Thumb: On-line Survival Tips Work offline unless you must be connected Avoid peak hours Let the system simplify and streamline your work Store names and addresses in an on-line address book Protect your privacy Cross-check on-line information sources Be aware of the amount of time you spend on-line Avoid information overload

 2001 Prentice Hall9.26 Converging Communication Technologies: From Messages to Money Alternative Technologies: On-line Information Services AOL, CompuServe, MSN, Prodigy Members pay a fee for these services Fax Machines and Modems “Never in history has distance meant less.” Alvin Toffler

 2001 Prentice Hall9.27 Alternative Technologies Voice Mail and Computer Telephony Global Positioning System Video Teleconferencing E-Money

 2001 Prentice Hall9.28 Building Bandwidth The quality of information transmitted through a communication medium depends upon bandwidth. –Increased bandwidth means faster transmission speed –Bandwidth is affected by the amount of network traffic, software protocols, and type of network connection

 2001 Prentice Hall9.29 Fiber Optic Cables Fiber optic cables are replacing aging copper lines They use light waves to carry information They provide data rates over one billion bits per second They offer extremely low error rates

 2001 Prentice Hall9.30 Digital Communication Comes Home Digital communication lines will soon be available in homes. They will provide us: Multi-person video phone conversations Universal Customized digital newspapers Automatic utility metering A variety of entertainment options