Our Digital WorldSecond Edition

Chapter 6

Communications and Network Technologies: Connecting Through Computers

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This chapter will help you be able to:

• Define computer networking and its uses.• Describe a communications system and how data is

exchanged.• Distinguish various types of transmission media.• Recognize the role of network standards and

protocols.• Describe various networking devices and software.• Explain the importance of network security.

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Main Topics

• 6.1 How Does the World Use Networking?• 6.2 Exploring Communications Systems• 6.3 Transmission Systems• 6.4 Communications Standards and Protocols• 6.5 Network Classifications• 6.6 Networking Devices and Software• 6.7 Securing a Network• 6.8 Interesting Trends in Networking

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Why Should You Care?

• Communications systems allow computing devices to send and receive data.

• Networks allow sharing of files, Internet connections, and devices.

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6.1 How Does the World Use Networking?

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The Many Uses of Networks

• A way to share files and resources.• Communicate with others.• Intranets and extranets.• Home networks.• The Internet.

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Terms to Know

• computer network• intranet• extranet

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Ask Yourself…

The Internet is a global network ofa. microwave towers.

b. social networks.

c. several networks linked together.

d. intranets.

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6.2 Exploring Communications Systems

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Communications Systems Illustrated

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Types of Signals

• Analog and digital.• Voice transmitted as

analog on phone lines.• Computers require a

digital signal.• Newer technologies

don’t require the conversion.

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Analog and Digital Signals

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Transmission Speed

• Data moves at different speeds.• Frequency and bandwidth.• Network traffic.• Broadband allows the transmission of a large

amount of data at fast speed.

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Frequency Speeds

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• communications system

• network protocol• analog signal• digital signal• modem• frequency• bandwidth

Terms to Know

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• broadband• kilobit per second (Kbps)• megabit per second (Mpbs)• gigabit per second (Gbps)• terabit per second (Tbps)• petabit per second (Pbps)

Terms to Know

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Ask Yourself…

The number of pieces of data that can be transmitted over a communications medium is called

a. frequency.

b. bandwidth.

c. broadband.

d. wavelength.

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6.3 Transmission Systems

Wired Transmissions

• Wired networks still in use.• Various types of cables:– Coaxial– Twisted-pair– Fiber-optic

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Wired Transmissions

• Coaxial• Twisted-pair• Fiber-optic

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Wireless Transmissions

• Cellular, microwave, and satellite.• Radio waves.• Signal strength and frequency.

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Cellular Technology

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Microwave Technology

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Satellite Communications

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• twisted-pair cable• coaxial cable• fiber-optic cable• cellular network• cellular transmission• microwave• satellite communication

Terms to Know

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Ask Yourself…

A cellular network sends transmissions usinga. microwave towers.

b. T-lines.

c. fiber-optic cable.

d. cell towers.

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6.4 Communications Standards and Protocols

What Are Standards and Protocols?

• Addressing issues of compatibility.• Standards organizations.• Communications standards called protocols.

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The Changing World of Voice Communications

• According to Silverman, why are people starting to reject electronic voice communication?

• Why might telephone numbers disappear?• Do advances in “Internet telephony” signal a

renaissance in voice communications?• Will video calling, like that offered by Apple

FaceTime, become the norm?• What might be the “next big thing” in the way people

use technology to network with each other?

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Network Transport Standards

• Ethernet.• Token ring.• TCP/IP.

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Wireless Networking Standards

• Wi-Fi.• WiMAX.• Bluetooth.• Radio Frequency Identification (RFID).• Wireless Application Protocol (WAP).

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Mobile Internet Usage

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Playing It Safe

• Public networks likely to be unsecured.• Don’t access financial accounts.• Secure your home wireless network.

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• standards• American National Standards Institute

(ANSI)• Institute of Electrical & Electronics

Engineers (IEEE)• protocol• Ethernet

Terms to Know

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• token ring• token• TCP/IP• packet• packet switching• Wi-Fi• 802.11 standard• hotspot

Terms to Know

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• WiMAX• Bluetooth• tethering• Radio Frequency Identification (RFID)• Wireless Application Protocol (WAP)• email server• webmail

Terms to Know

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Ask Yourself…

Computer standards allowa. different devices to talk to each other.

b. data files to be decrypted.

c. you to create email messages.

d. manufacturers to design computing devices.

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6.5 Network Classifications

Types of Networks

• Local Area Networks (LAN).• Metropolitan Area Networks (MAN).• Wide Area Networks (WAN).

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Network Architecture

• Sharing network resources.• Client/server.• Peer-to-peer (P2P).• Internet peer-to-peer (P2P).

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Client/Server Architecture

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Peer-to-Peer Architecture

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Network Topologies

• Arrangement of devices in a network.• Three kinds:– Bus topology– Ring topology– Star topology

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Bus Topology

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Ring Topology

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Star Topology

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• local area network (LAN)• server• wireless LAN (WLAN)• metropolitan area network (MAN)• wide area network (WAN)• network architecture• client/server network• client

Terms to Know

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• distributed application architecture• peer-to-peer (P2P) network• Internet peer-to-peer (P2P) network• topology• bus topology• ring topology• star topology

Terms to Know

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Ask Yourself…

Which type of network server is shown here?a. LAN.

b. MAN.

c. WLAN.

d. WAN.

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6.6 Networking Devices and Software

Network Devices

• Network devices include:–Modems.– Network adapters.–Wireless access points and routers.– Repeaters.– Hubs and switches.– Gateways and bridges.

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Network Devices

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Wireless Network Access Point

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Networking Operating Systems

• Used for managing networks.• Installed on the central server.

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• node• dial-up modem• DSL modem• cable modem• wireless modem• mobile broadband stick• network adapter• network interface card (NIC)• wireless interface card

Terms to Know

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• wireless access point• router• wireless router• repeater• hub• switch• gateway• bridge• network operating system (NOS)

Terms to Know

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Ask Yourself…

Each device connected to a network is called a(n)a. modem.

b. node.

c. interface card.

d. access point.

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6.7 Securing a Network

Network Security

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Computers in Your Career

• Computer security is a hot career.• Growth is due to increases in cyber

attacks and Internet-based applications.

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• firewall

Terms to Know

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Ask Yourself…

A combination of hardware and software that stops people outside a network from sending information into it is called

a. a network administrator.

b. network security.

c. a firewall.

d. a firebreak.

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6.8 Interesting Trends in Networking

Mobility and VoIP

• Building Wi-Fi and VoIP into intranets.• Saving money.

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Cloud Computing

• Software used from a network server.• Cloud services are flexible.

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Ask Yourself…A new networking trend is that companies are building this cost-saving feature into their internal networks

a. VoIP.

b. network servers.

c. firewalls.

d. cell towers.

Our Digital World

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