99 CHAPTER COMMUNICATIONS AND NETWORKS. © 2005 The McGraw-Hill Companies, Inc. All Rights Reserved....

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COMMUNICATIONS AND NETWORKS

9-2

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved.

Competencies

Discuss connectivity, the wireless revolution, and communication systems

Describe physical and wireless communications channels

Discuss connection devices

Describe data transmission factors

9-3


Competencies cont.

Discuss networks and key network terminology

Describe the different types of networks

Describe network architectures

Describe organizational uses of Internet technologies

9-4


What is Communication?

The process of sharing data, programs, and information between two or more computers

9-5


Communications Today

9-6


Communication Systems

9-7


Communication Channels

Channels carry data from one computer to

another

Two categories of communication channels

Physical connection

Wireless connection

9-8


Physical Connections

Telephone lines

Coaxial cable

Fiber-optic cable

9-9


Wireless Connections

Infrared

Broadcast radio

MicrowaveStations

Bluetooth

SatelliteUplink/Downlink

Global Positioning System

9-10


More on Satellites

Global positioning Network of 24 satellites

Owned by the Defense Department

Global positioning system (GPS)Devices used to determine location

Provides navigational support

9-11


Connection Devices

Types of signalsAnalog

Digital

Types of modemsInternal

External

PC Card

Wireless

9-12


Types of Connections

Digital subscriber line (DSL)Uses existing phone lines

ADSL (Asymmetric digital subscriber line)

Cable modemsUses existing TV cable

Provides speeds as fast as DSL at a lower cost

Satellite/air connection services Seven times faster than dial-up

Slower than DSL & cable modem

9-13


User Connection Costs & Speeds

Type Fee Speed Seconds to Get Images

Dial-up $16 56 kbps 45.0

DSL 50 1.5 mbps 1.7

Cable Modem 40 1.5 mbps 1.7

Satellite 70 900 kbps 2.8

9-14


Bandwidth

Measurement of the capacity of the channel

Categories Low bandwidths or Voiceband

Medium band

BroadbandUsed for high capacity transmission

Used by DSL, cable & satellite

9-15


Protocols

Set of communication rules

Standard for Internet: TCP/IPTransmission control protocol/Internet protocol

Identifies devices

Reformats information

9-16


Networks

A computer network is a communication system

Connects two or more computers

Allows information exchange

9-17


Network Terms

Node

Client

Server

Hub

Network interface cards (NIC)

Network operating system (NOS)

Distributed processing

Host computer

Network manager

9-18


Network Types

Local area networks

Home networks

Metropolitan area networks

Wide area networks

9-19


Network Architecture

Architecture describes how a network is arranged

Arrangement is called topology

Types of network topologyStar

Bus

Ring

Hierarchical

9-20


Star Network

Smaller computers linked to a central unit

Central unit is called the network hub

Control is maintained by polling

9-21


Bus Network

Each device handles its own communication control

There is no host computer

Has a common connecting cable called a backbone

9-22


Ring Network

Each device is connected to two other devices

No central file server or computer

Useful in a decentralized environment

9-23


Hierarchical Network

Several computers linked to a central host

Computers are hosts to other computers

Useful in centralized organizations

9-24


Strategies

Strategy is a way of coordinating the sharing of information and resources

Common network strategiesTerminal

Client/server

Peer-to-peer

Peer-to-Peer Network System

9-25


Organizational Internets

9-26


Internets and Extranets

IntranetsPrivate network within an organization

Provides information to employees

ExtranetsPrivate network that connects organizations

Used to allow suppliers and others access

FirewallsSecurity system

Protects against external threats

9-27


A Look to the FutureWireless Robotic Car

Pod car (Personalization on Demand)

Predicts and responds

Designed to learn and adapt to an individual's driving needs and habits

9-28


Key Terms

802.11 (239)analog signal (240)application server (243)asymmetric digital subscriber line (ADSL) (241)backbone (249)bandwidth (241)base station (245)bits per second (bps) (240)

Bluetooth (239)

broadcast radio (238)

broadband (242)

bus (249)

bus network (249)

cable modem (241)

cellular phone system (245)

client (243)

9-29


Key Terms

client/server network system (251)

coaxial cable (238)

communications (246)

communication channel (237)

communication device (237)

communication server (243)

communication system (237)

computer network (243)

connection device (237)

connectivity (236)

database server (243)

data transmission specification (237)

dedicated server (243)

9-30


Key Terms

demodulation (240)

dial-up service (240)

digital signal (240)

digital subscriber line (DSL) (241)

dish (239)

Distributed data processing system (249)

distributed processing (243)

Domain name server (DNS) (242)

downlink (239)

external modem (240)

extranet (243)

fiber-optic cable (238)

file server (243)

firewall (253)

Gnutella (252)

9-31


Key Terms

global positioning (239)

global positioning system (GPS) (239)

hierarchical network (249)

home network (245)

host computer (243)

hub (243)

hybrid network (249)

infrared (238)

internal modem (240)

intranet (253)

IP address (Internet Protocol address) (242)

LAN adapter (243)

line of sight communication (238)

Local area network (LAN) (244)

9-32


Key Terms

low bandwidth (241)

medium band (242)

metropolitan area network (MAN) (245)

microwave (239)

microwave station (239)

modem (240)

modulation (240)

Napster (251)

network administrator (243)

network architecture (248)

network gateway (244)

network hub (248)

network interface card (NIC) (243)

network manager (243)

9-33


Key Terms

network operating system (NOS) (243)

node (243)

packet (242)

PC card modem (240)

peer-to-peer network system (252)

polling (248)

printer server (243)

protocol (242)

proxy server (254)

receiving device (237)

regional network (245)

ring network (249)

satellite (239)

Satellite/air connection service (241)

sending device (237)

9-34


Key Terms

server (243)

star network (248)

strategy (250)

TCP/IP (transmission control protocol/Internet protocol) (242)

telephone line (238)

terminal network system (250)

time-sharing system (249)

T1, T2, T3, T4 lines (240)

topology (248)

transceiver (238)

transfer speed (240)

transfer rate (240)

transmission medium (237)

9-35


Key Terms

twisted pair (238)

uplink (239)

voiceband (241)

voice grade (241)

Web server (243)

wide area network (WAN) (245)

Wi-FI (wireless fidelity) (239)

wireless LAN (WLAN) (245)

wireless modem (240)

wireless receiver (245)

9-36


FAQs

What is fiber-optic cable?

My Palm Pilot uses Bluetooth. What is it?

What is a modem?

What is DSL? How does it work?

How fast is broadband bandwidth?

What is a local area network?

What is meant by peer-to-peer?

9-37


Discussion Questions

Discuss what is meant by the wireless revolution.

Discuss the four types of service connections.

Discuss the advantages and disadvantages of the four network topologies.

Explain the connections in a home network.

Describe the different network topologies.

Describe a GPS system.

99 CHAPTER COMMUNICATIONS AND NETWORKS. © 2005 The McGraw-Hill Companies, Inc. All Rights Reserved....

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Transcript of 99 CHAPTER COMMUNICATIONS AND NETWORKS. © 2005 The McGraw-Hill Companies, Inc. All Rights Reserved....