Networking

and

Telecommunicati

ons

9

 2001 Prentice Hall

9.2

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 Hall

9.3

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 Hall

9.4

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 Hall

9.5

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 Hall

9.6

• 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 Hall

9.7

a

a

Terminal

Modem

Modem

Analog

signals

Phone line

Digital

signals

Digital

signals

Computer

The word modem comes from
the
terms modulation and
demodulation

How a Modem Works

Modulation

Demodulation

 2001 Prentice Hall

9.8

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 Hall

9.9

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 Hall

9.10

WAN

(Wide Area Network)

LAN

(Local Area

Network)

Networks Near and Far

There are two general types of
computer networks:

 2001 Prentice Hall

9.11

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 Hall

9.12

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 Hall

9.13

WAN (Wide Area Network)

WANs are often made up of LANs

 2001 Prentice Hall

9.14

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 Hall

9.15

Client/Server Model

Client

Server

Client

software sends

requests from the user to the
server

Server

software responds to

client requests by providing
data

 2001 Prentice Hall

9.16

• 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 Hall

9.17

The Network Advantage

Networks allow

people to:

Lotus Notes is a client/server
application that facilitates
information sharing and
workgroup collaboration

–

Share computer
resources
(hardware
and software)

–

Share data

–

Work together
in new ways

 2001 Prentice Hall

9.18

E-Mail, 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 Hall

9.19

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 Hall

9.20

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: email and Newsgroups

 2001 Prentice Hall

9.21

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 Hall

9.22

Advantages of E-mail 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 Hall

9.23

Disadvantages of E-mail

and Teleconferencing

• Vulnerable to

machine errors,
human errors, and
security breaches

• Can pose a threat

to privacy

• Can be faked

 2001 Prentice Hall

9.24

Disadvantages of E-mail

and Teleconferencing

• Works only if the recipient

responds

• Can be overwhelming
• Both filter out many human

components of
communication

 2001 Prentice Hall

9.25

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 Hall

9.26

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 Hall

9.27

Alternative Technologies

 Voice Mail and

Computer Telephony

 Global Positioning

System

 Video

Teleconferencing

 E-Money

 2001 Prentice Hall

9.28

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 Hall

9.29

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 Hall

9.30

Digital Communication

Comes Home

Digital communication lines will soon be
available in homes. They will provide us:

• Multi-person video phone

conversations

• Universal e-mail
• Customized digital newspapers
• Automatic utility metering
• A variety of entertainment options