Introduction to In t ernet and World Wide Web

1. Eastern Mediterranean University School of Computing and Technology Department of Information Technology ITEC229 Client-Side Internet and Web Programming Introduction to Internet and World Wide Web CHAPTER 1 Prepared by: R. Kansoy

2. Contents 1.1 What is Internet? 1.2 History and Development of the Internet 1.3 Internet Standards & Coordination 1.4 Anatomy of the Internet 1.5 Bacis Internet Protocols 1.6 Technologies/Tools of the Internet 1.7 World Wide Web http://sct.emu.edu.tr/it/itec229

3. 1.1 What is Internet? • The Internet, sometimes called simply "the Net," is a worldwide system of computer networks - a network of networks in which users at any one computer can, if they have permission, get information from any other computer (and sometimes talk directly to users at other computers). • Originally the Internet served to interconnect laboratories engaged in government research, and since 1994 it has been expanded to serve millions of users and a multitude of purposes in all parts of the world. • In a matter of very few years, the Internet has consolidated itself as a very powerful platform that has changed the way we do business, and the way we communicate. http://sct.emu.edu.tr/it/itec229

4. 1.1 What is Internet? • The Internet, as no other communication medium, has given an International or, if you prefer, a "Globalized" dimension to the world. • Internet has become the Universal source of information for millions of people, at home, at school, and at work. • Internet is actually the most democratic of all the mass media. With a very low investment, anyone can have a web page in Internet. • This way, almost any business can reach a very large market, directly, fast and economically, no matter the size or location of the business. • With a very low investment, almost anybody that can read and write can have access to the World Wide Web. http://sct.emu.edu.tr/it/itec229

5. 1.2 History and Development of the Internet • It was conceived by the Advanced Research Projects Agency (ARPA) of the U.S. government in 1969 and was first known as theARPANet. • The original aim was to create a network that would allow users of a research computer at one university to be able to "talk to" research computers at other universities. • In time, ARPANET computers were installed at every university in the United States that had defense related funding. • Gradually, the Internet had gone from a military pipeline to a communications tool for scientists. • As more scholars came online, the administration of the system transferred from ARPA to the National Science Foundation. http://sct.emu.edu.tr/it/itec229

6. 1.2 History and Development of the Internet Brief History of the Internet • 1960 - US government seeks nuclear war proof communications, briefs project to APRA • 1968 - DARPA (Defense Advanced Research Projects Agency) contracts with BBN (Bolt, Beranek & Newman) to create ARPAnet • 1969 - Birth of Internet. Universities and researches connected to ARPAnet. • 1970 - First five nodes: • UCLA • Stanford • UC Santa Barbara • Universityof Utah, and • BBN http://sct.emu.edu.tr/it/itec229

7. 1.2 History and Development of the Internet • ARPANET • Implemented in late 1960’s by ARPA (Advanced Research Projects Agency of DOD) • Networked computer systems of a dozen universities and institutions with 56KB communications lines • Grandparent of today’s Internet • Intended to allow computers to be shared • Became clear that key benefit was allowing fast communication between researchers – electronic-mail (email) http://sct.emu.edu.tr/it/itec229

8. 1.2 History and Development of the Internet Brief History of the Internet • 1971 - Ray Tomlinson creates first network email application. • E-mail - a program to send messages across a distributed network. • 1972 – Telnet - Computers can connect more freely and easily • 1973 – FTP - computers send and receive data. • 1974 - TCP specification by Vint Cerf • 1977 - ARPAnetengineers realise the network is going to grow beyond expectations • 1983 - ARPAnet switched NCPto TCP/IP • 1984 - Domain Name System (DNS) was introduced. • 1989 - Tim Berners-Lee proposes a new set of Internet protocols • 1991 - World-Wide Web - developed released by CERN; withinthe UK academic network. • 1992/93 - Mosaic/Netscape - User Friendly Graphical Front • 1995 - US government releases Internet for commercial use http://sct.emu.edu.tr/it/itec229

9. 1.3 Internet Standards & Coordination • ICANN - The Internet Corporation for Assigned Numbers & Names • Non-profit organization • Main function is to coordinate the assignment of: • Internet domain names • IP address numbers • Protocol parameters • Protocol port numbers. http://sct.emu.edu.tr/it/itec229

10. 1.3 Internet Standards & Coordination • Internet Engineering Task Force (IETF) • http://www.ietf.org/ • Founded 1986 • Request For Comments (RFC) at http://www.ietf.org/rfc.html http://sct.emu.edu.tr/it/itec229

11. 1.3 Internet Standards & Coordination • W3C – World Wide Web Consortium • Develops recommendations and prototype technologies related to the Web • Producesspecifications, called Recommendations, in an effort to standardize web technologies http://sct.emu.edu.tr/it/itec229

12. 1.4 Anatomy of the Internet • Internet Backbone A high capacity communication link that carries data gathered from smaller links that interconnect with it. • NAP – Network Access PointAccess points or junctions to the Internet Backbone in major cities. http://sct.emu.edu.tr/it/itec229

13. 1.4 Anatomy of the Internet • Client/Server can describe a relationship between two computer programs – the "client" and the "server". • Client • requests some type of service (such as a file or database access) from the server. • Server • fulfills the request and transmits the results to the client over a network • The Internet Client/Server Model • Client -- Web Browser • Server -- Web Server http://sct.emu.edu.tr/it/itec229

14. 1.4 Anatomy of the Internet • Web Client • Connected to the Internet when needed • Usually runs web browser (client) software such as Internet Explorer or Netscape • Uses HTTP (Hypertext Transfer Protocol) • Connectto a web server using URL information • Requests web pages from server • Receives web pages and files from server • Displaythe formatted information http://sct.emu.edu.tr/it/itec229

15. 1.4 Anatomy of the Internet • Web Server • Continually connected to the Internet • Runs web server software (such as Apache or Internet Information Server) • Uses HTTP (Hypertext Transfer Protocol) • Receives request for the web page • Responds to request and transmits status code, web page, and associated files http://sct.emu.edu.tr/it/itec229

16. 1.5 Basic Internet Protocols • Protocols :rules that describe the methods used for clients and servers to communicate with each other over a network. • There is no single protocol that makes the Internet and Web work.A number of protocols with specific functions are needed. http://sct.emu.edu.tr/it/itec229

17. 1.5 Basic Internet Protocols • FTP(File Transfer Protocol) • A set of rules that allow files to be exchanged between computers on the Internet. • Web developers commonly use FTP to transfer web page files from their computers to web servers. • FTP is also used to download programs and files from other servers to individual computers. • E-mail Protocols • Sending E-mail • SMTP Simple Mail Transfer Protocol • Receiving E-mail • POP (POP3) Post Office Protocol • IMAP Internet Mail Access Protocol http://sct.emu.edu.tr/it/itec229

18. 1.5 Basic Internet Protocols • Transmission Control Protocol/Internet Protocol TCP/IP • TCP/IP has been adopted as the official communication protocol of the Internet. • TCP and IP have different functions that work together to ensure reliable communication over the Internet. http://sct.emu.edu.tr/it/itec229

19. 1.5 Basic Internet Protocols • Transmission Control Protocol (TCP) • Purpose is to ensure the integrity of communication • Breaks files and messages into individual units called packets • Internet Protocol (IP) • A set of rules that controls how data is sent between computers on the Internet. • IP routes a packet to the correct destination address. • The packet gets successively forwarded to the next closest router (a hardware device designed to move network traffic) until it reaches its destination. http://sct.emu.edu.tr/it/itec229

20. 1.5 Basic Internet Protocols • HTTP - Hypertext Transfer Protocol • A set of rules for exchanging files such as text, graphic images, sound, video, and other multimedia files on the Web. • Web browsers send HTTP requests for web pages and their associated files. • Web servers send HTTP responses back to the web browsers. HTTP Request HTTP Response http://sct.emu.edu.tr/it/itec229

21. 1.6 Technologies/Tools of the Internet • World Wide Web: a branch of the Internet that provides access tohyperlinked information. • E-mail: electronic message containing information sent from one computer to another overnetworks. • Listservs/mailing lists: a facility that allows participation in ongoing discussions via e-mail. • Usenet Newsgroups and discussion groups: world-wide distributed system of online discussion groups in which peoplecontinuously participate.Newsgroups allow people with a common interest to subscribeto one or more groups for posting, reading and replying to electronic mail. http://sct.emu.edu.tr/it/itec229

22. 1.6 Technologies/Tools of the Internet • Internet Relay Chat and web chatting: having a conversation with many people on a variety of topics in real time. All the parties to the conversation are participating simultaneouslyregardless of the time zone they are in. • Channels: Channels on the web are a pre-selected information source that can send information to yourcomputer automatically according to a predetermined schedule. • FTP: File Transfer Protocol allows you to copy files from one computer connected to theInternet to another computer connected to the Internet. It allows you to downloadinformation, upload web pages and transfer information between computers. • Telnet: The Telnet protocol is an application that allows a remote connection to anothercomputer. http://sct.emu.edu.tr/it/itec229

23. 1.6 Technologies/Tools of the Internet • Intranet: are private networks that help an organization to share informationbetween departments, units and regions across a network • Internet Phone: allows one toput a number of calls on the same line without sacrificing sound quality. • Video Conferencing: allows you to chat with one ormore people in real time and/or to see live images as you speak or type. • Blogs: Blogs or web logs are personal web pages that contain personal thoughts and links toother sites that are of particular interest to a blog owner. • Wikis: Wikis are collaborative websites where the community participate in writing apublication, like an encyclopaedia or a general purpose website. http://sct.emu.edu.tr/it/itec229

24. 1.7 World Wide Web (WWW) • Development of the Web • 1989-1991: Web invented by Tim Berners-Lee atEuropean Physics Laboratory (CERN). • 1993: Marc Andreesen and others at NCSA createMosaic, a Web browser with a graphical userinterface that could run on Windows, Macintosh, orUnix computer. • 1994: Andreesen and Jim Clark found Netscape,and create first commercial Web browser, NetscapeNavigator. • August 1995: Microsoft introduces its version of Webbrowser, Internet Explorer. Bill Clinton ”When I took office, only high energy physicistshad ever heard of what is called the World WideWeb... Now even my cat has it's own page.” http://sct.emu.edu.tr/it/itec229

25. 1.7 World Wide Web (WWW) • What is WWW? • is a way of accessing information over the medium of the Internet. • is one of the major services of the internet who hosts information of almost about anything one might like to search for. • computer network consisting of a collection of Internet sites that offer text and graphics and sound, video and animation resources through the hypertext transfer protocol. • The Web uses the HTTP protocol, only one of the languages spoken over the Internet, to transmit data. Web services, which use HTTP to allow applications to communicate in order to exchange business logic, use the Web to share information. • The Web also utilizes browsers, such as Internet Explorer or Firefox, to access Web documents called Web pages that are linked to each other viahyperlinks. http://sct.emu.edu.tr/it/itec229

26. 1.7 World Wide Web (WWW) • Web Browsers • a programme used to locate, display, browse and view information on awebsite. • when you request a web page by entering the URL in the location field of thebrowser, the browser contacts the web server and asks for a copy of the page. Thebrowser displays the page when it arrives. • abrowser can be text based in which caseyou would only be able to view web pages in text mode or could have a graphical userinterface in which case you would be able to view the web page in graphical mode. http://sct.emu.edu.tr/it/itec229

27. 1.7 World Wide Web (WWW) • Web Addresses • Each Web page has a unique address called the Uniform Resource Locator(URL). • The URL tells the computer how and where to look for a document. • Example: http://www.cnn.com/world/index.html • The hypertext links are attached to Web addresses. http://sct.emu.edu.tr/it/itec229

28. 1.7 World Wide Web (WWW) • Web Pages • A Web page is a file on the Web. • A Web site is a collection of Web pages maintained by a college, governmentagency, company or individual. • A Web page is created by using a computer language called HypertextMarkup Language (HTML). • HTML is a set of codes used to format Web pages and create links. http://sct.emu.edu.tr/it/itec229

29. 1.7 World Wide Web (WWW) • Hypertext • Web pages are hypertext documents. • A hypertext document is one that contains highlighted text or links thatconnect to other pages on the Web. • By clicking on the hypertext link you can go to another Web page on thesame computer, or a Web page on a computer across the world. • The Web uses a protocol called Hypertext Transfer Protocol (HTTP) totransfer documents containing hypertext. • HTTP's job is similar to that of TCP/IP.HTTP and TCP/IP, both protocols, or standards, tell computers how to communicate with eachother. Highlighted means that the text is usually underlined and displayed in a different color than the surroundingtext. Graphics can also be links. You simply point to and click on the text with your mouse to follow that link. http://sct.emu.edu.tr/it/itec229

30. Thank You ! Introduction to Internet and World Wide Web http://sct.emu.edu.tr/it/itec229 END of CHAPTER 1