Internet
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The document provides an overview of the history and development of the Internet. It discusses how the Internet originated from the ARPANET network created by the U.S. Department of Defense in the 1960s to enable communication between researchers even if parts of the network failed. It describes how standards like TCP/IP were developed in the 1970s and 1980s, allowing the Internet to grow rapidly from around 1,000 hosts in 1984 to over 200 million hosts by 2002. The document also summarizes how the Internet works, including topics like browsers, URLs, domain names, and different ways users can access the Internet through connections like LAN servers, dial-up, or online services.
Internet
- 2. What is the INTERNET? • The Internet is the system which connects computer networks. Internet links millions of computers all over the world. It allows your computer to get information stored on other computers far away. Computers connect to the Internet through telephone and cable systems. • The largest network of networks in the world. • Uses TCP/IP protocols and packet switching • Runs on any communications substrate.
- 3. • The Internet grew out of an experiment in the 1960s by the U.S. Department of Defense. The DoD wanted to create a computer network that would continue to function in the event of a disaster, such as a nuclear war. If part of the network was damaged or destroyed, the rest of the system still had to work. That network was ARPANET, (Advanced Research Projects Agency Network) which linked U.S. scientific and academic researchers. It was the forerunner of today's Internet. • 1968 - DARPA (Defense Advanced Research Projects Agency) contracts with BBN (Bolt, Beranek & Newman) to create ARPAnet • 1974 - TCP specification by Vint Cerf Where did the Internet come from?
- 4. • 1984 – On January 1, the Internet with its 1000 hosts converts en masse to using TCP/IP for its messaging • 1984Domain Name Server (DNS) introduced and number of host is 1,000 1986 NSFNET created a high speed backbone (56Kbps) to interconnect supercomputer centers 1987 Number of hosts breaks 10,000 1992 WWW released by CERN (a physics research institute in Switzerland)Number of hosts breaks 1,000,000 1995*.com sites exceed *.edu sites 1996 Electronic commerce gets going seriously
- 5. • The creation of the Internet solved the following challenges: – Basically inventing digital networking as we know it – Survivability of an infrastructure to send / receive high- speed electronic messages – Reliability of computer messaging Creation of the Internet
- 6. 1977: 111 hosts on Internet 1981: 213 hosts 1983: 562 hosts 1984: 1,000 hosts 1986: 5,000 hosts 1987: 10,000 hosts 1989: 100,000 hosts 1992: 1,000,000 hosts 2001: 150 – 175 million hosts 2002: over 200 million hosts By 2010, about 80% of the planet will be on the Internet Internet Growth Trends
- 7. • Transport control protocol (TCP) – A protocol that operates at the transport layer and is used in combination with IP by most Internet applications • Backbone – An Internet high-speed, long distance communications links (like a bus; wire that connects nodes) • Uniform resource locator (URL) – An assigned address on the Internet for each computer – E.g., http://www.yorku.ca/ How the internet works
- 8. Three Ways to Access the Internet
- 9. Access to the Internet • LAN servers • Local servers can provide access to the Internet through normal connections (e.g., Ethernet) • Serial line internet protocol (SLIP) and Point-to-point protocol (PPP) • Communications protocol software that transmits packets over telephone lines, allowing dial-up access to the Internet • Connection via an on-line service • Examples are America Online and Microsoft Network. These services usually require sign-up procedures
- 10. • The Web physically consists of your personal computer, web browser software, a connection to an Internet service provider, computers called servers that host digital data, and routers and switches to direct the flow of information. Net structure
- 11. • A web browser is the software program you use to access the World Wide Web, the graphical portion of the Internet. The first browser, called NCSA Mosaic, was developed at the National Center for Supercomputing Applications in the early 1990s. The easy-to- use point-and-click interface helped popularize the Web. Microsoft Internet Explorer and Netscape Navigator are the two most popular ones. Web Browser
- 12. • World Wide Web is a network of electronic files stored on millions of computers all around the world. Hypertext links these resources together. Uniform Resource Locators or URLs are the addresses used to locate the files. Every URL is unique and identifies one specific file. • example: http://www.mu.ac.in The home page of Mysore University. Web Addresses
- 14. • Every computer that hosts data on the Internet has a unique numerical address. For example, the numerical address for the White House is 198.137.240.100. But since few people want to remember long strings of numbers, the Domain Name System (DNS) was invented. DNS, a critical part of the Internet's technical infrastructure, correlates a numerical address to a word. To access the White House website, you could type its number into the address box of your web browser. But most people prefer to use "www.whitehouse.gov." In this case, the domain name is whitehouse.gov. Domain Names
- 15. Domain Affiliations Domain Affiliations Arts cultural and entertainment activities Com business organizations Edu educational sites firm businesses and firms gov government sites info information service providers mil military sites nom individuals net networking organizations org organizations rec recreational activities store businesses offering goods for purchase web entities related to World Wide Web activities net networking organizations