CHAPTER 14

CHAPTER Computer Network Computer Networks, Internet and Email Unit V . . Evolution of Networking Computers exchange data in automatic mode, is, essentially, the basic mechanism of any computer network. Developers of the first networks implemented services for file exchange, database synchronization, e-mail and other network services. . . . ARPANET ARPANET was established by the Advanced Research Projects Agency (ARPA) in for two main reasons: • To allow the transfer of data between various research institutes. • To answer the call of the U.S. Department of Defence for a technology to provide messaging capabilities to the government in the event of nuclear war. . . World Wide Web(WWW) The World-Wide Web is a collection of documents and services. It is distributed across the Internet and linked together by hypertext links. The web is therefore a subset of the Internet. World Wide Web was created by Timothy Berners Lee in at CERN in Geneva . Web page is a document available on World Wide Web. A web page can contain information including text, graphics, audio, video and hyper links. These hyper links are the link to other web pages. Web Browser is an application software that allows us to view and explore information on the web. Following are the most common web browser available today: Table . Browser Vendor Internet Explorer Microsoft Google Chrome Google Mozilla Firefox Mozilla Netscape Navigator Netscape Communications Corp. Opera Opera Software Safari Apple Sea Monkey Mozilla Foundation K-meleon K-meleon Request for web page Web page HTML file Internet Web browser (Client) Web browser Web page HTML file Request for web page Figure . WWW Operation Web server is a computer where the web content is stored. Basically web server is used to host the web sites. WWW Operation WWW works on client- server approach. Following steps explain how the web works: . The User enters the URL (say http:// of the web page in the address bar of web browser. . The browser then requests the Domain Name Server for the IP address corresponding to www. tngovernmentjobs.in. . After receiving the IP address, the