ch09 networks n comm

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Chapter 9Communications

and Networks


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Chapter 9 Objectives

Discuss the components required forsuccessful communications

Discuss the components required forsuccessful communications

Identify various sending

and receiving devices

Identify various sending

and receiving devices

Describe uses of computer communications

Describe uses of computer communications

List advantages of using a network

List advantages of using a network

Differentiate among client/server,peer-to-peer, and P2P networks

Differentiate among client/server,peer-to-peer, and P2P networks

Describe the various network

communications standards

Describe the various network

communications standards

Explain the purpose of

communications software

Explain the purpose of

communications software

Describe various types of lines for

communications over the telephone network

Describe various types of lines for

communications over the telephone network

Describe commonly used

communications devices

Describe commonly used

communications devices

Discuss different ways to set up

a home network

Discuss different ways to set up

a home network

Identify various physical and wireless

transmission media

Identify various physical and wireless

transmission media

Next


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Communications

What are computer communications?

Nextp. 460 Fig. 9-1

Process in which two or more computers or devices transfer data,

instructions, and information


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Uses of Computer Communications

What are some uses of communications technology?

Nextp. 462

WebWeb

WebWebInternetInternet

InternetInternet EE--MailMail

EE--MailMailInstantInstant

MessagingMessaging

InstantInstantMessagingMessaging

InternetInternet

TelephonyTelephony

InternetInternet

TelephonyTelephonyNewsgroupsNewsgroups

NewsgroupsNewsgroupsChat RoomsChat Rooms

Chat RoomsChat Rooms

WebWeb

FoldersFolders

WebWeb

FoldersFolders

Fax MachineFax Machine

orComputerorComputerFax/ModemFax/Modem

Fax MachineFax Machine

orComputerorComputerFax/ModemFax/Modem

VideoVideo

ConferencingConferencing

VideoVideo

ConferencingConferencingFTPFTP

FTPFTP


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What are wireless Internetaccess points and

cybercafs?

Nextp. 464 Fig. 9-5

Wireless Internet access

point allows wirelessconnection to Internetin public location

3G network

Cybercaf is coffee

house that providescomputers with Internetaccess

Click to view WebLink, clickChapter 9, ClickWeb Link from leftnavigation, then clickHot Spots belowChapter 9


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What is a global positioning system (GPS)?

Nextp. 466 Fig. 9-6

Step 1.GPS satellites orbit

Earth. Every

thousandth of a

second, each satellitesends a signal that

indicates its current

position to the GPS

receiver.

Step 2.A GPS receiver

(such as in a car,,

a watch, a smartphone, a

handheld device,

or a collar)

determines its

location on Earth

by analyzing at

least 3 separate

satellite signalsfrom the 24

satellites in orbit.

Click to view WebLink, clickChapter 9, ClickWeb Link from leftnavigation, then clickGPS belowChapter 9


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What are collaboration andgroupware?

Nextp. 467 - 468 Fig. 9-7

A document management

system provides for storage

and management of a

companys documents

Groupware is software

that allows people

to share

information

Collaboration is working

with other users connected

to a server


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What are voice mail and web services?

Nextp. 468 Fig. 9-8

Voice mail is voice message

converted to digital form

Web services describe

standardized software thatenables programmers to

create applications that

communicate with other

remote computers over theInternet or on an internal

business network


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Networks

What is a network?

Nextp. 469 Fig. 9-9

Collection ofcomputers anddevices connectedvia communications

devices andtransmissionmedia


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Networks

What is a local areanetwork (LAN)?

Nextp. 471 472 Fig. 9-10

Network in limited geographical area such ashome or office building

Wireless LAN (WLAN)

Metropolitan area network (MAN) connects LANs incity or town

Click to view WebLink, clickChapter 9, ClickWeb Link from leftnavigation, then clickWireless LocalArea NetworksbelowChapter 9


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Networks

What is a wide areanetwork (WAN)?

Nextp. 472 Fig. 9-12

Network that covers

large geographic

area using manytypes of media

Internet is worlds

largestWAN


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Networks

What is a client/servernetwork?


One or more computersact as server and othercomputers, or clients,access server


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Networks

What is a peer-to-peernetwork?


Simple network

that connects

fewer than 10computers

Each computer,

or peer, has equal

capabilities


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Networks

What is Internet peer-to-peer(P2P)?

Nextp. 473 - 474 Fig. 9-15

Enables users to

connect to each others

hard disks andexchange files directly

Click to view WebLink, clickChapter 9, ClickWeb Link from leftnavigation, then clickP2P belowChapter 9


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Networks

What is a bus network?


All computers and devices connect to central

cable,

or bus Example ofnetwork topology (layout of devices in

network)

Popular topologies are bus, ring, and star


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Networks

What is a ring network?


Cable forms closed

ring, or loop, with all

computers and devices

arranged along ring Data travels from

device to device

around entire ring, in

one direction


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Networks

What is a star network?


All devices connect to

a central device, called

hub

All data transferredfrom one computer to

another passes

through hub


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Networks

What is an intranet?

Nextp. 475

Extranet allows customers or suppliers to access

part of companys intranet

Typically includes connection to Internet

Makes information accessible to employees

Internal network that uses Internet technologies


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Network Communications Standards

What are Ethernet and token ring?

Nextp. 476

Ethernet technology allows computers to contend

for access to network

If two computers send data at same time,a collision occurs and computers must send again

Token ring technology controls access to networkby requiring devices to pass a special signal,

called tokenClick to view WebLink, clickChapter 9, ClickWeb Link from leftnavigation, then clickEthernet belowChapter 9


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What are TCP/IP and 802.11 (Wi-Fi)?

Nextp. 477 - 478 Fig. 9-20

TCP/IP (Transmission Control Protocol/Internet

Protocol) technology transmits data by breaking it up

into small pieces, or packets

Commonly used for Internet transmissions

802.11 (Wi-Fi) is family of standards for wireless LANs


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What is Bluetooth?

Nextp. 478

Short-range radio waves transmit

data between Bluetooth devices


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What are IrDA, RFID, WiMAX, and WirelessApplications Protocol (WAP)?

Nextp. 478 - 480

Click to view WebLink, clickChapter 9,Click Web Link from leftnavigation, then clickWiMAX belowChapter 9

IrDAIrDAspecification allows

data to be transferredwirelessly via infrared

light waves

IrDAIrDAspecification allows

data to be transferredwirelessly via infrared

light waves

Wireless ApplicationsWireless Applications

Protocol (WAP)Protocol (WAP)allow wireless mobile devices

to access Internet

Wireless ApplicationsWireless Applications

Protocol (WAP)Protocol (WAP)allow wireless mobile devices

to access Internet

Radio FrequencyRadio Frequency

Identification (RFID)Identification (RFID)uses radio signals to communicate

with a tag placed in an object

Worldwide InteroperabilityWorldwide Interoperability

for Microwave Access (WiMAXfor Microwave Access (WiMAX

or 802.16)or 802.16)

standard that specifies how wirelessdevices communicate over the air

in a wide area


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Video: Keep Tabs on Your Pets

Discover how to improve the odds of recovering a lost orstolen pet

low quality

(click to start)

high quality(click to start)

Next


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Communications Software

What is communications software?

Nextp. 480

Programs that help users

establish connection to

Internet, other network,

or another computer Programs that help usersmanage transmission of

data, instructions,

and information

Programs that provide an

interface for users to

communicate with oneanother


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Communications Over the Telephone Network

What is the public switchedtelephone network (PSTN)?


Worldwide telephone

system that handles

voice-orientedtelephone calls


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Communications Over the Telephone Network

What is a dial-up line?

Nextp. 481

Temporary connection using telephone line for

communications

Costs no more than making regular call

Computers at any two locations can establish aconnection using modems and telephone network


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Communications Devices

What are examples ofcommunications devices?

Nextp. 484

Common types are dial-up modems, ISDN and

DSL modems, cable modems, network cards,

wireless access points, routers, and hubs

ISDN and DSL modems send

and receive data from ISDN

and DSL lines


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What is a dial-up modem?

Nextp. 485 Figs. 9-27

Converts digital signals to analog signals and vice versa

Notebook computers often use PCCard modem


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What are ISDN and DSL modems?

Nextp. 485

Communications devices that send and

receive digital ISDN and DSL signals

Communications devices that send and

receive digital ISDN and DSL signals

Usually external devices in which one

end connects to a telephone line and the other

end connects to a port on the system unit

Usually external devices in which one

end connects to a telephone line and the other

end connects to a port on the system unit


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What is a cable modem?

Nextp. 485 - 486 Fig. 9-28

Sends and receives

data over cable

television network

Much faster than

dial-up modem orISDN

Sometimes called a

broadband modem

Click to view WebLink, clickChapter 9, ClickWeb Link from leftnavigation, then clickCable ModemsbelowChapter 9


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What is a wireless modem?


Allows access to the

Web wirelessly from

a notebook

computer, a PDA, asmart phone, or

other mobile device

Typically use the

same waves used bycellular telephones


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What is a network card?


Adapter card, PC

Card, or flash card

that enables

computer or deviceto access network

Sometimes called

network interface

card (NIC)


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What is a wireless access point?


Central

communications

device that allows

computers and

devices to transfer

data wirelessly among

themselves or

wirelessly to a wired

network


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What is a router?


Connects computers and

transmits data to correct

destination on network

Routers forward data onInternet using fastest available

path

Click to view WebLink, clickChapter 9, ClickWeb Link from leftnavigation, then clickHardware Firewalls belowChapter 9

Some routers have a built-in

hardware firewall


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What is a hub?

Nextp. 488 - 489 Fig. 9-33

Device that provides central

point for cables in network


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Home Networks

What is a home network?

Nextp. 489 - 490 Fig. 9-34

Multiple computers

connected in home

Several types of home

networks

Ethernet connect

computers via cable

Powerline cable use electrical lines in house

Phoneline

usetelephone lines

HomeRF (radio frequency)wirelessClick to view WebLink, clickChapter 9, ClickWeb Link from leftnavigation, then clickHome NetworksbelowChapter 9


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Communications Channel

What is a communications channel?

Nextp. 491

Transmission media on which data travels in

communications system

Bandwidth is amount of

data that can travel

over a communicationschannel

Transmission mediaare materials capable of

carrying one or more

signals


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Communications Channel

How is a request sent over theInternet using a communications

channel?



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Physical Transmission Media

What is physical transmission media?


Wire, cable,and other tangiblematerials usedto send

communicationssignals


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Physical Transmission Media

What are twisted-pair cable and coaxial cable?

Nextp. 493 Fig. 9-379-38

Twisted-pair cable is used for telephone systems and network cabling

Coaxial cable is often used for cable television wiring


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Wireless Transmission Media

What is wireless transmission media?


Used when inconvenient, impractical, or impossible to

install cables

Includes Bluetooth and IrDA


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What are broadcast radio and cellular radio?


Broadcast radio

distributes radio

signals over long

and short distances Cellular radio

is form of

broadcast radio

used for mobile

communicationsClick to view WebLink, clickChapter 9, ClickWeb Link from leftnavigation, then clickCellularCommunications belowChapter 9


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What is a microwave station?


Earth-based

reflective

dish used for

microwave

communications

Must transmit in

straight line with

no obstructions


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What is a communications satellite?


Space station

that receives

microwave signals

from earth-based

station, amplifiessignals, and

broadcasts signals

back to any

number of earth-

based stations


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Summary of Communications and Networks

Chapter 9 Complete

Communications terminologyand applications

Communications terminologyand applications

How to join computers into a networkHow to join computers into a network

Various communicationsdevices, media, and procedures

Various communicationsdevices, media, and procedures

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