1. Computers
© 2005 Prentice-Hall, Inc.
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2. Chapter 6 Networks and Networking
Computers
Chapter 6
Networks and Networking
© 2005 Prentice-Hall, Inc.
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3. Computers Chapter 6 – Networks and Networking
Objectives
Apply the concept of connectivity to your life
Understand data communications hardware
Identify data transmissions services
Understand the various network topologies
Recognize the potential of home networking
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4. Computers Networks and Networking
Our Wired World
Connectivity – the degree to which software, hardware, and databases are functionally linked
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5. Computers Networks and Networking
Our Wired World
Cooperative processing
Intracompany networking – cooperation within the company
Intercompany networking – cooperation with other companies and customers
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6. Computers Networks and Networking
Our Wired World
Intranet –internal network based on Internet technology
Extranet – an extension of an intranet, partially available to customers and suppliers
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7. Computers Networks and Networking
Our Wired World
Virtual Private Network (VPN) – network transmissions are tunneled through the Internet
Tunneling – one network uses another to send data
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8. Computers Networks and Networking
Data Communications Hardware
Data communications or telecommunications – distribution of data
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9. Computers Networks and Networking
Data Communications Hardware
Server computers – central computers that control the network
Client computers – computers, linked to a server, that create the network
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10. Computers Networks and Networking
Data Communications Hardware
Proxy server computers – handle some requests, hand others to the actual server computers
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11. Computers Networks and Networking
Data Communications Hardware
Telephone-link modem – converts analog signals to digital and digital signals to analog
Analog – voice communication, such as over a telephone line
Digital – 1’s and 0’s used to represent data in a computer
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12. Computers Networks and Networking
Data Communications Hardware
Modem
Internal
External
Voice/data/fax modem
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13. Computers Networks and Networking
Data Communications Hardware
Cable modem – provides Internet access via cable television lines
DSL (Digital Subscriber Line) – Internet access via special line provided by a telephone company
Satellite modem – Internet access via communications satellite
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14. Computers Networks and Networking
Data Communications Hardware
Network interface card (NIC) – also called network card and network adapter
Needed to connect a personal computer to a network
Ethernet – de facto standard
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15. Computers Networks and Networking
Data Communications Hardware
Gateway – allows for communication between networks using different protocols
Router – routes messages to the appropriate destination
Gateway router – both functions in one device
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16. Computers Networks and Networking
Data Communications Hardware
Message
Source – device that sends the message
Destination – device that receives the message
Handshaking – router establishes the connection between the source and the destination
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17. Computers Networks and Networking
Data Communications Hardware
Network address – assigned to each computer on a network; used to send messages to the appropriate destination
Backbone – the routers, gateways, and other equipment that link the computers of the network
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18. Computers Networks and Networking
Data Communications Hardware
Hub – expands the number of nodes on a network
Half-duplex – data can only be sent in one direction at a time
Switch – acts like a hub for a local area network (LAN)
Full-duplex – data can be sent in both directions at once
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19. Computers Networks and Networking
Data Communications Hardware
Terminals
Video Display Terminal – input/output device
Thin client – smart terminal, capable of some processing
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20. Computers Networks and Networking
Data Communications Hardware
Telephony – integration of telephones and computers
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21. Computers Networks and Networking
Data Communications Hardware
Automatic Teller Machine (ATM) – used in banking
Point-of-Sale (POS) terminals – used in retail
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22. Computers Networks and Networking
The Data Communications Channel
Communications channel – media a message must pass through on a network
Line
Link
Pipe
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23. Computers Networks and Networking
The Data Communications Channel
Transmission media
Measured in bits per second (bps)
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24. Computers Networks and Networking
The Data Communications Channel
Twisted-pair wire
POTS (plain old telephone services)
Digital Subscriber Line (DSL)
Cat5 cabling – uses four twisted pairs of wire; speeds of up to 100 M bps
Cat5e cabling – speeds of up to 1 G bps
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25. Computers Networks and Networking
The Data Communications Channel
Coaxial cable – high capacity channel, capable of speeds up to 10 M bps
Fiber optic cable – carries data as electrical signals
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26. Computers Networks and Networking
The Data Communications Channel
Wireless communication
Microwave signal – sent from one transmitter to another
Radio frequency (RF) signal – line-of-sight
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27. Computers Networks and Networking
The Data Communications Channel
Communications satellite – repeater for microwave transmissions in geosynchronous orbit
Geosynchronous orbit – 22,300 miles above the earth
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28. Computers Networks and Networking
The Data Communications Channel
Wireless networks
Access points – college campuses, coffee shops, local area networks
Wi-Fi – approximately 300 foot range
Bluetooth – approximately 30 foot range
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29. Computers Networks and Networking
The Data Communications Channel
Wireless Application Protocol (WAP)
Internet access standard for wireless devices such as cell phones
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30. Computers Networks and Networking
The Data Communications Channel
Future of wireless
Multichannel Multipoint Distribution Service (MMDS)
Local Multipoint Distribution Service (LMDS)
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31. Computers Networks and Networking
The Data Communications Channel
Common carriers
Examples: AT&T, Sprint, MCI
Private line (leased line) – charge based on channel capacity and distance
Switched line (dialup line) – time and distance charge
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32. Computers Networks and Networking
The Data Communications Channel
Communications protocols – rules established to govern the way data are transmitted in a computer network
Asynchronous transmission – data sent on an as-needed basis
Synchronous transmission – source and destination operate in timed synchronization
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33. Computers Networks and Networking
Node – terminal, PC, or any device connected to a network
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34. Computers Networks and Networking
Types of Networks
Personal Area Network (PAN) – connects cell phones or other electronics to the network
Local Area Network (LAN) – nodes are in close proximity
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35. Computers Networks and Networking
Types of Networks
Metropolitan Area Network (MAN) – network that encompasses a city
Wide Area Network (WAN) – nodes of the network are geographically distant
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36. Computers Networks and Networking
LAN resources that can be shared
Applications software
Links to other LANs
Communications capabilities
I/O devices
Storage devices
Add-on boards
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37. Computers Networks and Networking
LAN access methods
Network Access Method – rule that a network uses to determine priorities
Logical topology
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38. Computers Networks and Networking
Ethernet – widely used network access method; uses Carrier Sense Multiple Access/Collision Detection (CSMA/CD protocol)
Token Access Method
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39. Computers Networks and Networking
Servers
File server – stores programs and data to be shared via the network
Print server – handles print jobs
Communication server – provides access to other networks
LAN server – PC designed to be server
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40. Computers Networks and Networking
LAN software
Network operating system (NOS)
Peer-to-peer (P2P)
Dedicated server
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41. Computers Networks and Networking
LAN software
Peer-to-peer LAN – all PCs are equal in the network
Client/server LAN – NOS resides on the server computer
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42. Computers Networks and Networking
Application software for LANs
Client/server LAN applications software
Front-end application software – user interface and applications software processed locally
Back-end application software – handles tasks associated with storage and maintenance of databases
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43. Computers Networks and Networking
Application software for LANs
Download (server-to-client)
Upload (client-to-server)
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44. Computers Networks and Networking
Shared applications software
Groupware – allows a group of people to work on a project
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45. Computers Networks and Networking
Shared applications software
Electronic mail ( )
Instant messaging
Calendar and scheduling
Brainstorming
Shared whiteboarding
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46. Computers Networks and Networking
Shared applications software
Setting priorities
Electronic conferencing
Electronic forms
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47. Computers Networks and Networking
Home network – small LAN in the home
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48. Computers Networks and Networking
Home network technologies
Wired
Wireless
Home phoneline networking (HomePNA or HPNA) – uses existing telephone lines to create the network
HomePlug – uses electrical lines to connect computers in the network
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49. Computers Networks and Networking
Home network decisions
How many computers? Where will they be placed?
How much do you want to spend?
What is your networking expertise?
Do you expect the network to grow?
What applications do you want to run?
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50. Computers Networks and Networking
Steps to installing a home network
Install network interface cards
Set up communication hardware
Link PCs to router/hub/switch
Set up network software
Identify files/printers to be shared
Set up Internet connection sharing
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51. Computers Chapter 6 – Networks and Networking
Lesson Summary
Apply the concept of connectivity to your life
Understand data communications hardware
Identify data transmission services
Understand the various network topologies
Recognize the potential of home networking
© 2005 Prentice-Hall, Inc.
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