THE INTERNET & THE WORLD WIDE WEB Exploring Cyberspace

1. THE INTERNET & THE WORLD WIDE WEB Exploring Cyberspace 5 Chapter

2. Chapter Topics 2.1 Connecting to the Internet 2.2 How Does the Internet Work? 2.3 The World Wide Web 2.4 The Online Gold Mine 2.5 The Intrusive Internet

3. 2.1 Connecting to the Internet

4. Internet history • Began with 1969s ARPANET for U.S. Dept. of Defense • 62 computers in 1974 • 500 computers in 1983 • 28,000 computers in 1987 • Early 1990s, multimedia became available on Internet • 2010 = about 2 billion people on Internet • To connect you need • 1. An access device (computer with modem) • 2. A means of connection (phone line, cable hookup, or wireless) • 3. An Internet access provider

5. DEFINITION: Bandwidthis an expression of how much data – text, voice, video, and so on – can be sent through a communication channel in a given amount of time. DEFINITION: Basebandis a slow type of connection that allows only one signal to be transmitted at a time. DEFINITION: Broadband is a high-speed connection that allows several signals to be transmitted at once.

6. Data Transmission Speeds • Originally measured in bits per second (bps) • 8 bits are needed to send one character, such as A or a • Kbps connections send 1 thousand bits per second • Mbps connections send 1 million bits per second • Gbps connections send 1 billion bits per second • Uploading & Downloading • Upload—transmit data from local to remote computer • Download—transmit data from remote to local computer

7. High-Speed Phone Lines • DSL line • Uses regular phone lines, DSL modem • Receives data at 1.5 ̶ 10 Mbps; sends at 128 Kbps – 1.5 Mbps • T1 line—very expensive • Traditional trunk line; carries 24 normal telephone circuits • Transmission rate of 1.5 ̶ 6 Mbps (T3 = 6 – 45 Mbps) • Cable modem • Receives data at up to 30 Mbps; sends at about 1.4 Mbps

8. Satellite Wireless • Transmits data between satellite dish and satellite orbiting earth • Sends data at around 200 ̶ 512 Kbps; receives at 1 ̶ 5 Mbps • Connection is always on • User needs to buy or lease satellite dish and modem and have them connected

9. Other Wireless • Wi-Fi & 3G/4G • Wi-Fi—stands for “wireless fidelity” • Transmits data wirelessly up to 54 Mbps for 300 – 500 feet from access point (hotspot) • Typically used with laptops and tablets that have Wi-Fi hardware • 3G—stands for “third generation”; 4G = “fourth generation” • High-speed wireless that does not need access points, because it uses existing cellphone system • Used mostly in smartphones

10. Internet Access Providers • Two Types • 1. Internet Service Provider (ISP) — e.g., Earthlink and Comcast • Company that links online users to its servers, which link users to the Internet through another company’s network • 2. Wireless Internet Service Provider (WISP)— e.g., AT&T, Cingular, Verizon • Enables wireless-equipped laptop/tablet and smartphone users to access Internet

11. 2.2 How Does the Internet Work?

12. The Internet consists of hundreds of thousands of smaller networks • Protocols • The set of rules a computer follows to electronically transmit data. • TCP/IP (Transmission Control Protocol/Internet Protocol) is the Internet protocol • Developed in 1978 by ARPA; used for all Internet transactions • Packets • Fixed-length blocks of data for transmission • Data transmissions are broken up into packets and re-assembled at destination (the IP—Internet Protocol— address)

13. IP Addresses • Every device connected to the Internet has an address • Each IP address uniquely identifies that device • The address is four sets of numbers separated by periods (e.g., 1.160.10.240) • Each number is between 0 and 255

14. 2.3 The World Wide Web

15. Browsers, Websites, & Web Pages • The web and the Internet are not the same; the web is multimedia-based, and the Internet is not. The Internet is the infrastructure that supports the web. • Browsers • Software for web surfing (for accessing particular servers on the Internet); examples = Internet Explorer Mozilla FireFox Apple Macintosh’s Safari Google’s Chrome

16. Website • The location on a particular computer (server) that has a unique address; example = www.philadelphia.edu.jo • The website (server) could be anywhere — not necessarily at company headquarters • Web Page • A document on the web that can include text, pictures, sound, and video • The first page on a website is the Home page • The Home page contains links to other pages on the website (and often other websites)

17. TCP/IP— As explained, general Internet Protocol • HTTP—Protocol Used to Access World Wide Web • Hypertext Markup Language (HTML) • The “markup” language used in writing and publishing web pages • Set of instructions used to specify document structure, formatting, and links to other documents on the web • Hypertext links connect one web document to another

18. Web browsers interpret HTML and allow you to move around the Internet and the web • Come preinstalled on most PCs, but you can download others

19. Search Services & Search Engines • Organizations that maintain databases accessible through websites to help you find information on the internet • Examples: portals like Yahoo! and Bing, plus Google, Ask.com, Gigablast • Search services maintain search engines—programs that users can use to ask questions or use keywords to find information

20. Tagging • Tags: do-it-yourself labels that people can put on anything found on the internet, from articles to photos to videos • Can be shared easily with other people • Tags are available through delicious.com, BlinkList, Flickr

21. 2.4 The Online Gold Mine

22. Internet Telephony • Uses the Internet to make phone calls via VoIP (Voice over Internet Protocol) • Long-distance calls are either very inexpensive or free • With a PC that has a sound card, microphone, Internet connection with modem & ISP, and internet telephone software such as Skype and Vonage • Also allows videoconferencing

23. E-Commerce • E-Commerce (electronic commerce): conducting business activities online • B2B commerce is business-to-business e-commerce • Online finance involves online banking, stock trading online, and e-money such as PayPal • Online auctions link buyers with sellers (e.g., eBay) • Online job hunting match job hunters with employers Discussion Question: Have you every sold anything on eBay? Used PayPal? Did you have any problems? What would you warn people about?

24. Web 2.0 • The move toward a more social, collaborative, interactive, and responsive web; has led to the “social web,” giving rise to: • Social networking sites: Facebook, MySpace • Social networking website: an online community that allows members to: • Keep track of friends • Share photos, videos, music, stories, and ideas • Media-sharing sites: YouTube, Flicker, Shutterfly, etc. • Media-sharing website: type of online social network in which members share media such as photos, videos, music, ideas, and so forth

25. 2.5 The Intrusive Internet

26. Malware refers to software programs designed to damage or do other unwanted actions on a computer system. • Spamming • Cookies

27. Spam: Electronic Junk Mail • Unsolicited email that takes up your time • Delete it without opening the message • Never reply to a spam message • When you sign up for something, don’t give your email address • Use spam filters • Fight back by reporting new spammers to www.abuse.net or www.spamhaus.org

28. Cookies • Little text files left on your hard disk by some websites you visit • Can include your log-in name, password, and browser preferences • Can make visiting these websites next time more convenient and faster • But cookies can be used to gather information about you and your browsing habits; this information can be used without your consent