ch05.ppt

Chapter 05: Telecommunications,

Wireless Technologies, and Computer Networks

Succeeding with Technology, Third Edition 2

Objectives• Understand the fundamentals of data

communications and the criteria for choosing a communications medium

• Explain how networking media, devices, and software work together to provide data networking services, and describe the benefits of various types of media

Succeeding with Technology, Third Edition 3

Objectives• List and describe the most popular forms of

wireless telecommunications technologies

• List the different classifications of computer networks and their defining characteristics, and understand the basics of wireless home networking

Succeeding with Technology, Third Edition

Chapter Content• Fundamentals of Telecommunications• Networking Media, Devices, and Software• Wireless Telecommunications Technologies• Networks and Distributed Computing

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Fundamentals of Telecommunications

• Communications

– Transmission of a signal by way of a medium

• Signal

– Contains message comprised of data and information

• Communication medium

– Anything that carries a signal between a sender and a receiver

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Telecommunicationsand Data Communications• Telecommunications

– Electronic transmission of signals for communications

• Data communications– Electronic transmission and reception of digital data

• Telecommunications network – Connects communications and computing devices

• Networking media – Anything that carries an electronic signal

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Telecommunicationsand Data Communications• Networking media

– Anything that carries a signal and creates an interface between a sender and receiver

• Networking hardware devices and networking software work together to enable and control communications signals

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Telecommunicationsand Data Communications

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Characteristics of Telecommunications

• Analog signal– Fluctuates continuously

• Digital signal– Discrete voltage– State is either high or low– The speed at which a signal can change from high to low is

called the signal frequency• Bandwidth

– Data transmission rate– Measured in bits per second (bps)

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• Broadband or high-speed Internet– Connection that is always on or active– Faster than dial-up

• Narrowband– Any medium with a speed less than 200 Kbps

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Networking Media – Physical Cables

• Twisted pair cable – Consists of pairs of twisted wires covered with an

insulating layer

• Coaxial cable– Consists of an inner conductor wire surrounded by

insulation, a conductive shield, and a cover

• Fiber-optic cable– Consists of thousands of extremely thin strands of

glass or plastic bound together in a sheathing

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• Fiber-optic cable has several advantages over traditional copper cable– Speed– Size– Clarity– Security

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Radio Signals and Light• Radio wave

– Electromagnetic wave transmitted through an antenna at different frequencies

– FCC assigns different frequencies for different devices

• Microwaves– Sent at the high end of the spectrum (1-300 GHz)

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Networking Devices• Modems

– Modulates and demodulates signals – Cable modem

• Provides Internet access over a cable television network

– DSL modem • Provides high-speed Internet service over telephone lines

• Network adapter– Computer circuit board, PC Card, or USB device

• Network interface card (NIC)• Wireless adapters

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Networking Devices

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Network Control Devices• Hubs

– Used as a central point for connecting a series of computers

• Switches– Fundamental part of most networks– Allow several users to send information at the same time

without slowing the network

• Repeaters– Connect multiple network segments

• Bridges– Connect two or more network segments

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Network Control Devices• Gateways

– Network points that act as an entrance to another network

• Routers – Can divide a single network into two logically

separate networks• Wireless access point

– Receives and transmits data to wireless adapters • Firewall

– Device or software that filters the information coming onto a network, generally to increase security and remove unwanted traffic

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Industrial TelecommunicationsMedia and Devices• Microwave transmission

– Also called terrestrial microwave– Line-of-sight medium

• Communications satellite – Basically a microwave station placed in outer space

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Industrial Hardware• Dedicated line

– Unlike a switched line, a dedicated line remains open at all times

• T1 line– Carries twenty-four 64-Kbps signals on one line

• T3 line– Carries 672 signals on one line

• Devices commonly used to control and protect industrial-level telecommunications:– Multiplexer– Communications processor– Encryption devices

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Networking Software• Networking software

– Monitors the load, or amount of traffic, on the network

– Provides error checking and can often indicate problems and possible solutions

– Can provide data security and privacy

• Network administrator or systems administrator– Person responsible for setting up and maintaining the

network

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Networking Software• Network Operating Systems (NOS)

– Perform same functions for network as operating system software performs for a computer

• Network Management Software– Facilitates monitoring of individual computers and shared

hardware

• Network Device Software– Often contain interfaces that allow you to change device

settings

• Communications Protocols and Standards– Ethernet: most widely used network standard for private

networks

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Networking Software

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Cell Phone Technologies• Cellular network

– A radio network – Geographic area is divided into cells with a transceiver

antenna and station at the center of each cell

• 3G cellular technology– Brings broadband access to mobile phones

• Cellular carrier– Company that builds and maintains cellular network– Provides cell phone service to the public

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Cell Phone Technologies• Calling plans are defined by usage in three time

frames:– Whenever, or anytime, minutes with no time

restrictions– Weeknight minutes

• Monday through Friday, 9:00 p.m. to 5:59 a.m. or 6:59 a.m.

– Weekend minutes• Saturday 12:00 a.m. to Sunday 11:59 p.m.

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Handsets, Features, and Services• Two basic styles of phone

– Flip phone– Candy bar

• Accessories– Case– Headset or earbud

• Hands-free use

– Bluetooth– Additional memory

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Handsets, Features, and Services

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Handsets, Features, and Services

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Pagers• Small, lightweight devices that receive signals

from transmitters• Types of paging systems

– National and regional systems • Set up transmission towers to cover large geographic areas

– On-site paging systems • Use small desktop transmitters to send pages over a small

wireless network

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Global Positioning Systems (GPS)• Uses satellites to pinpoint the location of objects

on earth• Uses a GPS receiver and a network of 24 satellites

– GPS can tell exact location of receiver on the earth’s surface

• GPS – Originally developed for national security and later

extended for public use– Child safety

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Global Positioning Systems (GPS)

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Wireless Fidelity and WiMAX• Wireless fidelity (Wi-Fi)

– Makes use of access points to wirelessly connect users to networks within a range of 250–1000 feet (75-300 meters)

– Standards• Known as the 802.11 family of standards

– Typical at wireless hotspots• Developed by the Institute of Electrical and Electronics

Engineers (IEEE) • Developed to support wireless computer networking

within a limited range at broadband speeds• Access points broadcast traffic using radio waves

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Wireless Fidelity and WiMAX• WiMAX

– Known as IEEE 802.16– Faster and longer range than Wi-Fi– WiMAX antenna has 31-mile range

• Perfect for city-wide Internet access

– Seattle’s Space Needle has a WiMAX antenna– Intel and Nokia are strongly supporting WiMAX

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Bluetooth• Enables digital devices to communicate directly

with each other wirelessly over short distances• Communicates at speeds of up to 1 Mbps within

a range of up to 33 feet (10 meters)• Can connect devices to a computer network

using access points like Wi-Fi• Bluetooth and Wi-Fi compete in some areas, but

have unique qualities

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Bluetooth

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Infrared Transmission• Involves sending signals through the air via light

waves– Infrared Data Association (IrDA ports)

• Slower than both Bluetooth and Wi-Fi• Uses light rather than broadcast technology• Ideal for secure data transmissions

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Radio Frequency Identification (RFID)

• Uses tiny transponders in tags that can be– Attached to merchandise or other objects – Read using an RFID transceiver or reader for the

purpose of identification– Primarily used to track merchandise from supplier to

retailer to customer

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• Other uses for RFID– Tracking lost pets– Tagging and tracking wildlife– Controlling access to secure locations– Automatic toll pay– Talking prescription reader– Parking lot control– Track marathon runners

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Networks and Distributed Computing

• Within a private network– Computing resources are shared in order to maximize

computing power

• Computer – Includes devices for input, processing, storage, and

output– Components can be distributed throughout a

computer network

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Computer Networking Concepts• Nodes

– Devices attached to a network• Workstations

– Computers attached to a network• Local resources

– Files, drives, or other peripheral devices connected to the workstation and accessible via the network

• Network or remote resources– Workstation accesses over the network– Transparency provides user-friendly environment

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Distributed Computing• Distributed Computing

– Multiple remote computers working together

• Database servers– Store databases and respond to queries

• File servers– Store files and deliver them to users upon request

• Application servers– Store programs and deliver them to desktops when

users click the icon

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Distributed Computing• Blade computing

– Cheaper alternative– Takes advantage of the fact that at any one time,

30% of system PCs are not being used

• PCs are replaced with thin clients– Keyboard, mouse, display, unit to connect the device

to the server– Thin clients cost less than half the cost of a PC

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Distributed Computing

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Network Types• Personal area network (PAN)

– Interconnecting personal information technology devices– Typically wireless

• Local Area Network (LAN)– Connects computer systems within same building – Can use various designs or topologies

• Intranet – Uses protocols of the Internet and the Web within the

confines of a private network

• Virtual Private Network (VPN)– Enables private Internet communications

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Network Types• Metropolitan area network (MAN)

– Connects networks within a city or metropolitan-size area into a larger high-speed network

• Wide area network (WAN)– Connects LANs and MANs between cities, across country, and

around the world • Global Networks

– A WAN that crosses an international border (transborder data flow)

– Data havens have few restrictions on telecommunications or databases

• Electronic Data Interchange (EDI)– Connects corporate computer systems

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Network Types

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Network Types

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Home Networks• Allow residents to

– Share a single Internet connection– Share a single printer between computers– Share files such as images, music, and programs– Back up copies of important files to another PC for

safekeeping– Participate in multiplayer games– Share output from devices, such as a DVD player or

Webcam

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Home Networking Technologies• Convenient setups• Phone-line networking (HomePNA)

– Uses existing phone lines

• Power-line networking (HomePLC)– Uses existing power lines and outlets

• Wireless networking– Can easily support everything a typical home user

might want to do on a network

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Home Network Applications• Rapid rise of Wi-Fi in homes is spurring new

home technologies– Data storage and access

• Photos, etc.

– Media distribution in the home• Wireless music systems• Wireless video and Internet• TV to TV signal sharing

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Home Network Applications

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Summary• Telecommunications

– Refers to the electronic transmission of signals for communication

– Networking media, devices, software

• Types of cables used in telecommunications– Twisted pair cables, coaxial cable, and fiber optic

cable

• Networking devices include – Modems, network adapters, network control devices,

RFID devices, and pagers54


Summary• Cellular network

– Radio network – Geographic area is divided into cells with a transceiver

antenna (tower) and station at the center of each cell • Networks are classified by size

– PAN, MAN, WAN, GAN• Server computers

– Used to distribute data, files, and programs to users, or clients, on the network

• Home networks – Used to share hardware, files, and a common Internet

connection

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