INTERNET

INTRODUCTION TO INTERNET

Internet is a worldwide network that is a widely used to connect universities, government offices, companies and private individuals.

A machine to be on the Internet means it runs TCP/IP protocol stack, has an IP address, and has the ability to send IP packets to all the other machines on the Internet. A private individual having a personal computer can call up an Internet service provider using a modem, be assigned a temporary IP address, and send IP packets to other Internet hosts.

An Internet consists of a set of connected networks that act as an integrated whole. The Internet provides universal interconnections while allowing individual groups to use whichever network hardware is best suited to their needs. As a network of networks, it provides a capability for communication to take place between research institutions, individuals, and among all ‘Internet Citizens’.

As a complex system of interlinked networks, the Internet supports millions of ‘servers’ computers housing large volumes of all sorts of information. The Internet is where millions of friends and strangers can chat. It lets people browse through thousands of on –line libraries, play new games, and trade software. Another feature of the Internet is that it has no geographic bounds. Users are logging on from India to the US, India to Australia etc.

Internet Applications can be classified as follows:

1. E-mail: facilitates the composition, transfer and receiving of mails from one system to another.
2. News: newsgroups are specialized forums in which users with a common interest for example technical (computers, science etc) or non-technical(recreation,etc), can exchange messages.
3. Remote Login: Users anywhere on the Internet can log in to any other machine on they have an account.
4. File Transfer: Files can be copied from one machine on the Internet to another. Files   be of articles, databases or any other information.
5. World Wide Web: A site can set up a number of pages of information containing sound and video, with embedded links to other    pictures,pages. By clicking on a link, a user can be shifted to another page pointed to by that link. For example, a company may have a home page that may point to other pages, which give product information, price lists, sales, stockholder information etc. Information regarding almost everything is available on the Internet due to WWW.                                                                                                                                                                                                                                                                                                                                                                                               There are a variety of ways for individuals, companies, or institutions to connect to the Internet. Large organizations usually connect by means of direct, dedicated, high-speed links to give their users high bandwidth networking capabilities. Home users connect by means of a telephone line and a modem. Users search the Internet for all types of information, including images, graphics, and sound and movie clips, in an ever growing number of remote host computers. When users retrieve and distribute this information to others, network activity becomes highly intensive in terms of file transfer times and traffic volume. This is now fueling the upgrade of the Internet to wide band and broadband access and backbone facilities. WWW, an Internet environment, was a break through which began in 1993. It is just a software scheme for imposing order over the mass of free-form information on the Internet by organizing it into easily understood pages. Hyperlinking is a software technique that has made the web a powerful cyber helper. When composing a web page, an author can create hyperlinks-words that appear in bold type and indicate a path to some other information. Using a program known as a web browser on a personal computer or workstation, one can read pages stored on any web computer.

Many kinds of information are now available on World Wide Web servers. WWW offers hypertext technology that links together a ‘web’ of documents so that these can be navigated in any number of ways with the use of sophisticated Internet-specific graphical user interface (GUI) software (for example, Mosaic, Netscape, Explorer). WWW may also provide information consisting of hypermedia in which contents may include graphics video, voice, and/or music a part form text. Web server software now also allows the delivery of live, real-time audio and video

Magazines, specs, documents, advertisements, technical information etc., of interest to business people are available on servers, generating considerable corporate traffic as knowledge workers access them via the enterprise network. Specifically, the WWW is a set of public specifications and a library of code for building information servers and clients. WWW is ideal to support cooperative work in complex research fields. WWW uses Internet–based architectures employing public and open specifications along with free sample implementations on the client and server end, so that any one can build a client or a server.

The three key components of WWW are:

1. URL (Uniform Resource Locator)
2. HTTP(Hyper Text Transfer Protocol)
3. HTML

A URL is the address of the document, which is to be retrieved from a network server. It contains the identification of the protocol, the server, and the filename of the document. When the user clicks on a link in a document, the link icon in the document contains the URL, which the client employs to initiate the session with the intended server.

HTTP is the protocol used in support of the information transfer. It is a fixed set of messages and replies that both the server and the client understand. The document itself, which is returned using HTTP upon the issuance of a URL, is coded in HTML. The browser interprets the HTML to identify the various elements of the document and render it on the screen of the client.

HTML specifications are reasonable for 2-dimensional page layout, but not necessarily for truly interactive browsing. Newly emerging languages such as Virtual Reality Modeling Language (VRML) and Java are designed to enhance the web browsing experience. VRML offers a method of describing 3-dimensional space so that user can navigate in 3-D. Java is an object-oriented program that adds animation and real time interaction through in line applications.

Activities running on Web servers that are CPU-and communications-intensive include applications generating real-time graphics using charts and colors to show trends in the stock market, voter returns, Geographic Information Systems (GISs), weather maps, database statistics, and analysis related to e-commerce.

Some of the Web server software is based on the concept of streaming media, which delivers audio and video on demand, rather than requiring a user to download a file from the web and play it back from the local server or hard drive.

The Internet provides connectivity for a wide range of application processes called network services. One can exchange electronic mail, access and participate in discussion forums, search databases, browse indexes, transfer files, and so forth. TCP and IP were developed for basic control of information delivery across the Internet. Application layer protocols, such as TELNET, FTP, SMTP, and HTTP, have been added to the TCP/IP suite of protocols to provide specific network services.

Hardware components of the Internet include routers, PCs, workstations, and servers. Software vendors include NetScape, spyGlass, spry, NetManage, Microsoft, and PC-NFS. Carriers include providers of dial-up access and providers of dedicated access (for example, inter exchange carrier).

• Written by Lohit Seth.
• In category Computer Science.
• 14 years ago.

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