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