The Internet From Greenlaw/Hepp, In-line/On-line: Fundamentals of the Internet and the World Wide...

From Greenlaw/Hepp, In-line/On-line: Fundamentals of the Internet and the World Wide Web 1

The InternetThe Internet

IntroductionIntroduction

• The Internet Defined• Internet History• The Way the Internet Works• Internet Congestion• Internet Culture• Business Culture and the Internet• Collaborative Computing and the Internet



• Introduction• The Information Superhighway• Interesting Internet Facts

The Internet DefinedThe Internet Defined



• Federal Networking Council (FNC)• Global information system

• Logically linked IP addresses • Supports communications using TCP/IP• Provides services publicly and privately

The Internet DefinedIntroductionIntroduction



• Analogous to freeways and cars

Internet•Learning to surf (easy)•Learning to navigate•Building Web pages•Developing Web-related software/tools

Freeways/Cars•Learning to drive (easy)•Learning highways, etc.•Routine maintenance/repairs•Performing complex repairs

The Internet DefinedThe Information SuperhighwayThe Information Superhighway



• 25,000 new users daily• 325 million users (October 2000)• 343.25 million users projected (October 2002)• 50% of users are female• 73 million hosts (October 2000)• 200+ countries connected• World Wide Web sites double every two months

The Internet DefinedInteresting Internet FactsInteresting Internet Facts



• 1960s Telecommunications• Packet Switching vs. Circuit Switching• Advanced Research Projects Agency Network (ARPANET)

• 1970s Telecommunications• Local Area Network (LAN)

• 1980s Telecommunications• Transmission Control Protocol/Internet Protocol (TCP/IP)

• 1990s Telecommunications• Gopher, World Wide Web, Mosaic, Netscape

• Internet Growth

Internet HistoryInternet History


The InternetThe InternetInternet History



Early 1960s• Packet switching1969• Advanced Research Project Agency Network

(ARPANET)• Bolt, Beranek, and Newman, Inc. (BBN)• U.S. Department of Defense• Four nodes (hosts)

Internet History1960s Telecommunications1960s Telecommunications



1970s• Local area networks (LANs)• Open architecture1972• ARPANET nodes increased to 23• Ray Tomlinson invented e-mail




1976• UNIX to UNIX CoPy (UUCP) developed1979• User Network (USENET) developed

• Connection between Duke University and University of North Carolina at Chapel Hill

• Newsgroups emerged




1980• Computer Science Network (CSNET)

• U. S. university computer science departments

1981• Because It’s Time Network (BITNET)

• City University of New York and Yale University• Mailing lists




1983• TCP/IP required for all ARPANET hosts

• No charge (open system)• Allowed Internet growth

1985• National Science Foundation Network (NSFNET)

• NSF’s 5 super-computing centers




1988• Internet Worm

• Virus written by Robert Morris• Infected 10% of Internet hosts

• Internet Relay Chat (IRC)• Jarkko Oikarinen




1989• NSF took over ARPANET By the end of the 1980s• Domain Name System (DNS)• 100,000+ Internet hosts




• Commercial organizations on-line• URLs appeared in advertisements• Graphical browsing tools developed• HTML allowed users everywhere to publish on

the World Wide Web




1991• Gopher

• University of Minnesota

• World Wide Web (WWW)• Tim Berners-Lee at CERN

1992• WWW publicly available




1993• Mosaic released

• Graphical browser for Web• Marc Andreessen at University of Illinois• “Each person who used it, loved it and told five

friends.”




1994• Netscape Navigator released

• Netscape Communications• Marc Andreessen and Jim Clark

• Yahoo!• David Filo and Jerry Yang (Stanford University)




1995• Java

• Sun Microsystems, Inc.

• Microsoft Internet Explorer• Internet courses in colleges1998• Netscape Navigator source code released




• 100% each year• 16+ million computers linked • Reasons for success:

• Decisions not politically based• Internet is distributed operation• Homogeneity of language and outlook• Inherently interesting to people• Free (or inexpensive) software

Internet HistoryInternet GrowthInternet Growth



The Way the Internet WorksThe Way the Internet Works• Network Benefits• Interconnected Networks and Communication• Physical Components• Network Connections• Client-Server Model• IP Addresses• Internet Protocol Version 6 (IPv6)• Web Page Retrieval



• Convenience• Resource sharing• Facilitates communication• Monetary savings• Reliable• Scalable

The Way the Internet WorksNetwork BenefitsNetwork Benefits



• TCP/IP (Transmission Control Protocol/Internet Protocol)

• How computers connect, send, and receive information

• TCP permits communication between computers• IP specifies how data is routed to and from

computers

The Way the Internet WorksInterconnected NetworksInterconnected Networksand Communicationand Communication



• Example 1: Sending an e-mail message• Formatted according to Simple Mail Transfer

Protocol (SMTP)

• Example 2: Requesting a Web page• Formatted according to Hyper Text Transfer Protocol

(HTTP)




• Message split into IP packets:• Pieces of message• Information about sender• Information about receiver• Sequence number• Error checking information




• Destination (receiving) computer:• Reassembles message• Sends request for corrupt packets to be resent

• Advantages of packets:• Error recovery• Load distribution• Flexibility



The InternetThe InternetThe Way the Internet Works



• Servers• Answer service requests

• Routers• Direct data packets

• Networks• Transport packets• Copper wires, fiber-optic cables, radio waves,

microwaves, infrared light, and visible light

The Way the Internet WorksPhysical ComponentsPhysical Components



• Two modems• One, used to connect to Internet• Another, used by Internet Service Provider

(ISP)• Maximum connection speed usually 56 Kbps• Converts analog to digital

• Network Interface Cards• Connect PCs in LANs

The Way the Internet WorksNetwork ConnectionsNetwork Connections



• Integrated Services Digital Network (ISDN)• Regular telephone lines and special adapters • Five times faster than traditional modems

• Cable television connection• Teledesic (Bill Gates and Craig MacCraw)• Low-earth-orbit satellites




• Network Service Provider (NSP)• Local ISPs connect to NSPs• Leased-lines from local telephone companies• Transmit data at 1.54 megabits (Mbps)• IBM Avantis, AT&T, MCI, Sprint




• Generalization of interaction between clients and servers• Client makes request• Server responds

The Way the Internet WorksClient-Server ModelClient-Server Model



• Unique numerical name identifying each computer on Internet

• Vs. domain name• People-oriented unique name using symbols

• 32 bits (four bytes)• Four natural numbers separated by dots

(i.e., 132.177.4.124)• Network component and host component

The Way the Internet WorksIP AddressesIP Addresses



• Vital in packet switching• Network Information Center (NIC)

• Assigns IP addresses

• IP address to domain names• Resolver converts symbolic name to IP address

• Programs convert IP addresses to symbolic names (vice versa)• nslookup (UNIX-based systems)




• Point-to-Point Protocol (PPP)• Static IP address

• Permanent• Connection through router

• Dynamic IP address• Changes with each Internet connection• Connection through ISP




• Major changes:• More addresses

• IP address size from 32 bits to 128 bits• Simplified IP headers

• Reduction of header fields in IP packet• Added security features

The Way the Internet WorksInternet Protocol Version 6Internet Protocol Version 6



• Enter a URL

(1) Browser determines “how” part of URL is HTTP (2) Browser queries the DNS for IP address (3) DNS responds with IP address (4) Browser establishes TCP connection to IP

address (5) Browser sends a request for “what” portion of the URL

The Way the Internet WorksWeb Page RetrievalWeb Page Retrieval



• Enter a URL

(6) Server sends back the file requested (7) TCP connection closed (8) Browser renders text portion of HTML (9) Browser repeats steps for image files(10) Browser displays images as retrieved

The Way the Internet WorksWeb Page RetrievalWeb Page Retrieval



• World Wide Wait Problem• Technical Solutions• Issues and Predictions

Internet CongestionInternet Congestion



• Delays while using Internet• Reasons:

• Increase in Internet users• Elaborate Web pages

Internet CongestionWorld Wide Wait ProblemWorld Wide Wait Problem



• World Wide Web Consortium (W3C) issues: • Improving process of connecting• New techniques to expedite Web page requests• Refining how URL resolved

• Web page design suggestions:• Avoid unnecessary graphics• Cascading Style Sheets (CSS)• PNG instead of GIF

Internet CongestionTechnical SolutionsTechnical Solutions



• Intranets• Isolated, private network with an internal Web

• Cost• Inexpensive• Is it time to charge more for use of the Internet?

Internet CongestionIssues and PredictionsIssues and Predictions



• Critical Evaluation of Information• Freedom of Expression• Communication Mechanisms• Advertising• Societal Impact

Internet CultureInternet Culture



• Who wrote the information?• Is the writing quality high?• Is the document up to date?• Are there obvious errors in the content?

Internet CultureCritical Evaluation of InformationCritical Evaluation of Information



• Lack of regulation• Blue ribbon• Obscene or offensive material• Censorship• Platform for Internet Content Selection (PICS)

Internet CultureFreedom of ExpressionFreedom of Expression



• E-mail and mailing lists• Internet Relay Chat (IRC)• Newsgroups• Videoconferencing• Emoticons and shorthand• Flaming and SHOUTING

Internet CultureCommunication MechanismsCommunication Mechanisms



• Clickable images• Revolving advertisements

Internet CultureAdvertisingAdvertising

Societal ImpactSocietal Impact

• Jobs• Information and communication

• Weather, news, stock prices, travel information



• On-line Businesses• On-line Business Hurdles• Cookies• Business and Safety/Security on the Web• Legal Environment• U.S. Government’s Commitment to Electronic Commerce

Business Culture and the InternetBusiness Culture and the Internet



• Advertising, marketing, partnership, retail, service, software, subscription

Business Culture and the InternetOn-line BusinessesOn-line Businesses

On-line Business HurdlesOn-line Business Hurdles

• Privacy and security• Cookies



• File (on your disk) containing data about you• Created while on Internet

• Filling out a form• Encrypted

• Setting a cookie• Persistent cookie

Business Culture and the InternetCookiesCookies



• Secure payment (credit cards)• Secure Electronic Transactions (SET)• Electronic money

Business andBusiness andSafety/Security on the WebSafety/Security on the Web

Business Culture and the Internet



• New and uncharted territory• Taxes and tariffs

Business Culture and the InternetLegal EnvironmentLegal Environment



• President Clinton (July 1997)• Framework for the Global Electronic Commerce

• Policy on Global Information Infrastructure (GII)• Principles:

– Encourage self-regulation of Internet– Should not restrict e-commerce– Provide legal environment– Acknowledge uniqueness– Promote globally

U.S. Government’sU.S. Government’sCommitment to Electronic CommerceCommitment to Electronic Commerce

Business Culture and the Internet



• Collaborative Computing Defined• Applications• Impact• Future Prospects

Collaborative Computing and the InternetCollaborative Computing and the Internet



• Applications that allow sharing of information and resources between people• World Wide Web

• Collaborative computing platform supporting HTML• Groupware

• Collaborative computing platform software on networked computer system

Collaborative Computing and the InternetCollaborativeCollaborative Computing DefinedComputing Defined



• E-mail• Intelligent form• Version control• Videoconferencing

• Business meeting (VC)• Desktop Videoconferencing (DTVC)• Requires more bandwidth• CUSeeMe

Collaborative Computing and the InternetApplicationsApplications



• Convenience and time• Money

Collaborative Computing and the InternetImpactImpact

Future ProspectsFuture Prospects

• Intranet• Firewall

The Internet From Greenlaw/Hepp, In-line/On-line: Fundamentals of the Internet and the World Wide...

Documents

Transcript of The Internet From Greenlaw/Hepp, In-line/On-line: Fundamentals of the Internet and the World Wide...