Module 12: The Internet and WWW

1. A brief history of the Internet2. World Web Web, a application of the Internet3. Underlying technology4. Browsers and URL5. Internet applications6. Intranet

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A Quick Timeline

• ARPANET developed in 1969– Designed to connect computers at four locations– Designed to be resistant to disruption

• E-mail, file transfer, and remote access are basic applications of the ARPANET

• National Science Foundation connected its large network, NSFnet to ARPANET in 1986– Resulting network became known as the Internet

• World Wide Web is the mostly used Internet application– Made the Internet took off– Proposed and implemented by Tim Berners-Lee,1994

– The first browser, Mosiac was written by Marc Andreessen

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Tim Berners-Lee• Worked at CERN lab in Geneva

– Thought his work would be easier if he could link to colleagues’ computers

– Envisioned a network of computers much like a spider web

– Used links to transfer data from one site to another location

– Developed the first web server and a text based browser

• CERN site considered the birthplace of the World Wide Web

• Tim Berners-Lee is the director of W3C (World Wide Web Consortium, a non-profit organization for the standard format of Web document.

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Marc Andreesen

• Developed the first graphical browser– Called Mosaic– Led to Netscape

Navigator– Licensed to Microsoft

for IE

• Netscape

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Internet Links

• A link on a Web site is easy to see

– Either underlined and colored text or an icon

– Clicking the link transfers data from that site to the user’s computer

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Browser

• Interface software used to explore the Internet– Early browsers were text-

only– Mosaic was the first

graphical browser

• Graphical browsers combine ease of links with attractive graphical interface

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Underlying Technology• A message sent over the Internet is divided into uniformly sized

packets– Each packet labeled with its destination address

• Transmission Control Protocol/Internet Protocol (TCP/IP)– TCP creates and reassembles packets– IP handles delivering packets to the destination according to

the IP address

• IP address– Every host computer on the Internet has an IP address,

which is bit string of 32 bit, – usually represented by four decimal numbers, each for 8 bits.– The IP address of WLU’s web server is 192.54.242.121– Most IP address has a domain name (easy to remember)

192.54.242.121 www.wlu.ca– DNS (domain name system) translate a domain name to IP

address before the packet is transferred.

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The Internet Service Provider and the Browser

• An Internet service provider (ISP) provides the server computer and software to connect to the Internet– Online service, such as America

Online, includes Internet access, Internet service, and a browser

• When you connect to the Internet, the browser displays a home page– Uniform Resource Locator (URL)– Plug-ins– Web page programs

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Uniform Resource Locator (URL)

• The complete, unique address of a Web page

– Web page URL begins with http• HyperText Transfer Protocol – allows communication by using

links to transfer data between sites

– Domain name – an alias of the IP address of site’s host computer

– Following the domain name is the path to the web page on server machine.

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Internet Applications

• Searching the Internet

• Traditional applications of the Internet– FTP– Telnet– E-mail– Newsgroups

• E-commerce– Business-to-consumer (B2C)– Business-to-business (B2B)– Consumer-to-consumer (C2C)

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Searching the Internet

• Search Engine – lets a user specify search terms– Search engine builds database of

sites that match those terms– Uses spider software to build

database– Metasearch – searches search

engines and builds comprehensive list

• Internet directory– database

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File Transfer Protocol (FTP)

• A protocol for transferring files among computers

• FTP servers maintain collections of downloadable files– Downloading can often be done anonymously, without

logging in

• Many FTP servers can be accessed through Web browser

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Telnet

• A protocol that allows remote users to log onto a host computer – Users use their own PCs– Users log in over the Internet– Users’ experience is the same as if they were

sitting at the host computer’s local terminal

• Remote user typically has to have a user ID and password

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E-Mail

• The most commonly used feature of the Internet

• Network provides mail server

• E-mail client software on your computer

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Mail Server

• Collects and stores messages in mailbox

• E-mail address consists of user name, followed by @ symbol, then domain name of mail server

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E-Mail Client Software

• Allows you to manage your e-mail messages

• Features– Address books– The ability to attach files

• Some e-mail servers block all attached files

– Filters• Direct incoming e-mail to specific folders• Block spam

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The World of E-Commerce

• Electronic commerce - buying and selling over the Internet

• Three forms– Business-to-consumer (B2C)– Business-to-business (B2B)– Consumer-to-consumer (C2C)

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Business-to-Consumer

• Businesses selling goods to consumers– Has received the most media attention– Estimates of U.S. online sales

• $48 billion in 2002• Projected $130 billion by 2006

• Several models– Pure-play– Bricks-and-clicks– Flips-and-clicks

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Pure-Play Model

• Companies operate exclusively over the Internet– Some have their own

warehouses– Others relay orders to

manufacturer or wholesaler

• Examples include Amazon.com and etoys.com

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Bricks-and-Clicks Model

• Traditional retail outlets that have established a Web site– Name is a play on “bricks

and mortar”

• Examples include J.C. Penney and Macys– Well-known brand names– Loyal customer base

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Flips-and-Clicks Model

• Traditional mail-order retailers that have established Web sites– Catalogs placed on Web sites– Allow customers to replace

flipping pages with clicking links and icons

• Examples include L.L. Bean and Land’s End– Allows retailer to reach many

more customers

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Business-to-Business

• Businesses selling to other businesses– Has not received much media attention– Estimates of worldwide sales

• $1.9 trillion in 2002• Projected $8.5 trillion by 2005

• Internet exchanges are being developed to provide electronic marketplaces

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Internet Exchanges

• Create a marketplace– Bring together many buyers and

sellers

• Advantages– Reduced costs of procurement

(purchasing)– The ability to consider many

suppliers

• Potential concerns– Security– Antitrust concerns (possible

price-fixing)

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Consumer-to-Consumer

• Takes place on online auction sites

• Make buying and selling unique items easy– Your item is visible to

anyone in the world with an Internet connection

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Payments and Taxes

• E-commerce payments– Some people are leery of submitting credit card

information online– Secure Sockets Layer (SSL) protocol provides a

secure way to make online payments

• E-commerce taxes– Internet Tax Freedom Act provides tax relief on

Internet commerce– Commission studies the effects of taxation of Internet

commerce– Act set to expire in 2005