Digital Planet Tomorrows Technology and You George Beekman
Digital Planet: Tomorrow’s Technology and You George Beekman • Ben Beekman Tenth Edition Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
Digital Planet: Tomorrow’s Technology and You Chapter 8 Networking and Digital Communication Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
Chapter 8 Objectives ü Describe the basic types of technology that make telecommunication possible ü Describe the nature and function of local area networks and wide area networks ü Discuss the uses and implications of several different forms of online communication and collaboration ü Explain how wireless network technology is transforming the ways people work and communicate Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 3
Chapter 8 Objectives (cont. ) üDescribe how wireless phone networks are converging with digital data networks and the impact of that convergence üDescribe several ways to maximize effectiveness and minimize risks of online communication üDescribe how online social networks, wikis, and other new tools for creating online communities compare to traditional forms of community building üDescribe current and future trends in telecommunications and networking Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 4
Arthur C. Clarke’s Magical Prophecy • Arthur C. Clarke: predicted the use of geostationary communications satellites • Considered to be the father of satellite communications Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 5
Basic Network Anatomy ü A computer network is any system of two or more computers that are linked together. ü Three essential components of every computer system: • Hardware • Networks enable people to share computer hardware resources • Software • Networks enable people to share data and software programs. • People • Networks enable people to work together, communicate, and play together Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 6
Networks Near and Far ü LAN (local area network): computers are physically close to each other – usually in same building • Nodes: connected to hubs or switches, which allow any node on the network to communicate with any other ü Ethernet: popular networking architecture developed in the 1970 s; now an industry standard • Most networked computers today are connected to networks today by ethernet cables, plugged into ethernet plugs. ü Each node in a wireless network has a radio transmitter. • Convenient for small networks in homes and small businesses • Generally slower than wired LANs Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 7
Networks Near and Far (cont. ) ü WAN (wide area network): extends over a long distance • Each networked LAN site is a node on the WAN • Mostly used to link geographically dispersed corporate or government offices • Can use web of telephone lines, microwave relay towers, and satellites that span the globe ü Routers: hardware devices or software programs that route messages between networks ü Mesh networks: alternative to networks that uses centralized routers • Message hops from wireless device to wireless device Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 8
The Importance of Bandwidth ü Bandwidth: refers to the amount of data that can be transmitted through a communication medium in a given amount of time ü Typically measured in kilobits or megabits per second Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 9
The Importance of Bandwidth (cont. ) ü Bandwidth can be affected by: • Physical media of the network • Amount of traffic on the network • Type of network connection ü Fast Ethernet: carries traffic at 100 megabits per second; provided all devices are fast Ethernet compatible ü Gigabit Ethernet: standard is capable of transferring 1 gigabit of data per second Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 10
Bandwidth (cont) ü Bandwidth is on the rise between LANs, due to fiber-optic cables that are replacing copper wires in the worldwide telephone network. ü Fiber optic cables use light waves to carry information at lightening speeds ü A single fiber-optic cable can replace 10, 000 copper telephone cables. • Used to connect most major communication hubs around the world. ü Many large businesses & government institutions are connected to the global fiber-optic network • Most homes and small businesses depend on copper wires for the “last mile”. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 11
Communication Software ü Protocol: set of rules for the exchange of data between devices • Computers must follow the same protocols to understand each other. • Have code for messages like “Are you ready”. , “I am about to start sending a data file, and “Did you receive that file” ü TCP/IP: most famous protocol for computer networking • TCP/IP controls the exchange of data. • Will be discussed in detail in next chapter Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 12
Communication Software (cont. ) ü Communication software takes many forms: • NOS (network operating system): a system handles communications among many workstations • Examples: Novell’s Netware or Microsoft’s Windows Server • Shields users from nuts-and-bolts level of detail • Must be able to respond to requests from many computers. • Client/server model: one or more computers act as dedicated servers and all the remaining computers act as clients • Used by some LANs Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 13
• Peer-to-peer model: every computer on the network is both client and server • Used by many small networks, including most home networks • Also called p-to-p or P 2 P • Most desktop operating systems include all the software needed to operate a peer-to-peer network Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 14
Linking In: Internet Connection Technologies ü Early Day Connections • Direct connection: a hardwired connection • Faster than other connections • Used by many businesses and schools • Dial-up connection: uses modem and standard phone lines • Modem stands for modulator/demodulator. • Also called narrowband connections ü Broadband connection: greater bandwidth than modems Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 15
Linking In: Internet Connection Technologies (cont. ) ü Most common broadband alternatives: • DSL (digital subscriber line): uses telephone lines that carry voice calls • Cable modems: use same network of coaxial cable as television signals • Satellite connections: use dishes that provide television channels • Wireless connections: used by growing numbers Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 16
Wireless Network Technology Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 17
Wi-Fi Technology • Wireless access point (WAP): central connection point for wireless devices • A Wi-Fi hot spot • Wireless: Typically up to 120 feet indoors and 300 feet outdoors. • Use the 2. 4 GHz and 5 GHz band of the radio spectrum • Wide usage: Millions installed in homes, schools, businesses, coffee shops, airports, restaurants, libraries, etc. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 18
Wi-Fi and Wi. Max Technology • Wi. MAX (or 802. 16): new long-distance radio-based wireless standard in which a single tower can provide access to a 25 -square-mile area • Line-of-sight connections up to 30 miles • Can be used to connecting Wi-Fi networks • Wi-Fi Area Security: If not secure, skilled snoopers can “sniff” network traffic with laptop and read what you are writing, collecting email addresses and personal information • WEP (wired equivalent privacy): encryption scheme improves the security of wireless networks • VPN (virtual private network): electronic "tunnel” through the Internet that helps to prevent eavesdropping Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 19
Bluetooth Technology ü Bluetooth technology: named for Danish king who overcame his country’s religious differences • Overcomes differences between mobile phones, handheld computers, and PCs, allowing communication between different operating systems • Range is limited to about 30 feet • PAN (personal area network): links a variety of electronic devices using Bluetooth technology • Mobile phone to headset • Wireless keyboard and mouse to keyboard • Wireless game controller to the game console Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 20
3 G and 4 G Technology ü 3 G and 4 G technology: 3 G networks carry multimedia data and voice communications simultaneously • Used to support communications for mobile phones • Lack true broadband speeds • 4 G networks have gigabit broadband speeds • Larger mobile devices like the i. Pad compete with phones for bandwidth on these networks • Tethering: cabling a laptop to a mobile phone so it can send and receive Internet data through the phone’s wireless Internet connection Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 21
Specialized Networks: From GPS to Digital Money • GPS (Global Positioning System): specialized network of the U. S. Department of Defense • GPS receiver uses signals broadcast by satellites to determine its position. • At any point on planet, four satellites will be above the horizon. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 22
The Network Advantage ü Networks enable people to: • Share computer hardware resources • Print servers accept, prioritize, and process print jobs • Share data and software programs • Site licenses reduce costs for multiple copies of software • Work, play, and communicate together • Groupware enables several users to work on the same document at the same time. • E-commerce: Financial networks make credit card purchases, automatic bill paying, electronic funds transfer, etc. possible Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 23
A Home Computer Network Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 24
The Many Faces of Email ü Email is built on protocols. ü SMTP (Simple Mail Transfer Protocol): sending mail ü POP (Post Office Protocol) or IMAP (Internet Message Access Protocol): receiving mail ü Webmail: Web-based email, such as Gmail or Hotmail ü Attachments: formatted documents that are sent with an email ü Many email messages are in plain ASCII text – which require only limited band-width. ü Often email software can handle HTML, which allows formatting and inclusion of pictures. ü HTML use normally slow down email programs ü HTML allow email to carry web bugs • Can notify sender of message opening, when received, and personal information Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 25
Email Issues ü Spam: unsolicited, junk email constitute the majority of email. • Some spam sneaks through even the best email filters ü Phishing: luring people into fake Web sites to capture sensitive financial information ü Spreading Viruses: Mainly contained in attachments and cost billions of dollars of damage ü Mailing lists: enable you to participate in email discussion groups • Moderated groups ensure quality of the discussions. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 26
Newsgroups, Web Forums, and Blogs ü Newsgroups: public discussion on a particular subject • Messages posted on virtual bulletin board to read by anyone at anytime ü Web forums: accessed through a Web browser • Some require membership to post • Newsgroups & forums may be moderated to stop unproductive message. ü Blogs: (we. B LOG) frequently updated online journals • Political Blogs are an important source of unmonitored information Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 27
Instant Messaging, Text Messaging, and Teleconferencing ü Asynchronous communication: poster and reader don’t have to be logged in simultaneously ü IM (instant messaging): real-time communication ü Text messaging: uses SMS technology; more limited than IM ü Chat room: public or private virtual conference room Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 28
Computer Telephony • Voice mail: voice messaging system • Internet telephony: also called Voice-over IP • Many smart phones can connect to the Internet. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 29
Online Survival Tips • Let your system do as much work as possible. • Store names and addresses in a computeraccessible address book. • Don’t share emails and passwords. • Protect your privacy. • Don’t open suspicious attachments. • Don’t get hooked by a phishing expedition. • Keep your security systems up to date. • Cross-check online information sources. • Beware of urban legends. • Be aware and awake. • Avoid information overload. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 30
Social Networking, Role Playing, and Virtual Communities ü Facebook, Linked. In, Plaxo: social networking services ü Social networking sites: have privacy and safety issues ü MMORPGs (massively multiplayer online roleplaying games): success requires cooperation among groups of players Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 31
Information Sharing: Social Bookmarking, Wikis, Media Sharing, and Crowdsourcing ü Wiki: Web site designed to enable anyone who accesses it to contribute to it ü You. Tube is a cultural phenomenon for video sharing. ü Viral video: popular video that spreads as a virus through email, blogs, or IMs ü Crowdsourcing: large community of people work on a task Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 32
Netiquette and Messaging Etiquette • Say what you mean; say it with care. • Keep it short. • Proofread your messages. • Don’t assume you are anonymous. • Learn the “nonverbal” language of the Net. • Know your abbreviations. • Keep your cool. • Don’t be a source of spam. • Say no—and say nothing—to spam. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 33
Sharing Resources: Peer-to-Peer, Grid, and Cloud Computing ü Peer-to-peer: file sharing allows users to share files by making their hard drives available to other users rather than posting them on a central server ü Grid computing: sharing processing power rather than sharing data ü Cloud computing: form of grid computing where the resources come from the Internet rather than a specific source Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 34
Digital Communication in Perspective ü New technologies emerge all the time. ü Social networking is relatively new, but it has greatly changed the way we communicate. ü Wikis and MMORPGs are at the heart of Web 2. 0. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 35
Summary ü Networking is an important trend in computing today. ü LANs are made up of computers that are in close proximity. ü Most networks use the Ethernet architecture. ü High-bandwidth connections can transmit large amounts of information quickly. ü Wi-Fi makes it easy to connect devices to the Internet. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 36
Summary (cont. ) ü Issues of privacy, security and censorship will continue as the Internet grows. ü Email, instant messaging, and teleconferencing are the most common forms of communication on computer networks. ü Peer-to-peer computing was popularized by music-sharing services. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 37
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