All about the Internet: Description & Facts

Introduction to Internet

Internet is defined as an Information super Highway, to access information over the web. However, It can be defined in many ways as follows:

Internet is a world-wide global system of interconnected computer networks.
Internet uses the standard Internet Protocol (TCP/IP).
Every computer in internet is identified by a unique IP address.
IP Address is a unique set of numbers (such as 110.22.33.114) which identifies a computer location.
A special computer DNS (Domain Name Server) is used to give name to the IP Address so that user can locate a computer by a name.
For example, a DNS server will resolve a name http://www.google.com to a particular IP address to uniquely identify the computer on which this website is hosted.
Internet is accessible to every user all over the world.

It is the largest network in the world that connects hundreds of thousands of individual networks all over the world.
The popular term for the Internet is the “information highway”.
Rather than moving through geographical space, it moves your ideas and information through cyberspace – the space of electronic movement of ideas and information.

No one owns it
It has no formal management organization.
As it was originally developed by the Department of defense, this lack of centralization made it less vulnerable to wartime or terrorist attacks.
To access the Internet, an existing network need to pay a small registration fee and agree to certain standards based on the TCP/IP (Transmission Control Protocol/Internet Protocol) .

Uses of the Internet & Advantages

Advantages
Internet covers almost every aspect of life, one can think of. Here, we will discuss some of the advantages of Internet:
Internet allows us to communicate with the people sitting at remote locations. There are various apps available on the web that uses Internet as a medium for communication.e.g.facebook ,twitter ,yahoo,orkut.
One can surf for any kind of information over the internet. Information regarding various topics such as Technology, Health & Science, Social Studies, Geographical Information, Information Technology, Products etc can be surfed with help of a search engine.
Apart from communication and source of information, internet also serves a medium for entertainment. Following are the various modes for entertainment over internet.e.g. Online Television, Online Games,Songs,Videos.
internet allows us to use many services like: Internet Banking, Matrimonial Services, Online Shopping, Online Ticket Booking, Online Bill Payment,Data Sharing

Uses

Send e-mail messages.
Send (upload) or receive (down load) files between computers.
Participate in discussion groups, such as mailing lists and newsgroups.
Surfing the web.

Intranet

Intranet is defined as private network of computers within an organization with its own server and firewall. Moreover we can define Intranet as:
Intranet is system in which multiple PCs are networked to be connected to each other. PCs in intranet are not available to the world outside of the intranet.
Usually each company or organization has their own Intranet network and members/employees of that company can access the computers in their intranet.
Every computer in internet is identified by a unique IP address.
Each computer in Intranet is also identified by a IP Address, which is unique among the computers in that Intranet.
The most popular browsers are Microsoft Internet Explorer
and Netscape Navigator

What is Web?

The Web (World Wide Web) consists of information organized into Web pages containing text and graphic images.
It contains hypertext links, or highlighted keywords and images that lead to related information.
A collection of linked Web pages that has a common theme or focus is called a Web site.
The main page that all of the pages on a particular Web site are organized around and link back to is called the site’s home page.

What is a Web Browser

A Web browser contains the basic software you
need in order to find, retrieve, view, and send
information over the Internet. This
includes software that lets you:
▪Send and receive electronic-mail (or e-mail)
messages worldwide nearly instantaneously.
▪Read messages from newsgroups (or forums) about
thousands of topics in which users share
information and opinions.
▪Browse the World Wide Web (or Web) where you can find a rich variety of text, graphics, and interactive information

How to access the internet

Many schools and businesses have direct access to the Internet using special high-speed communication lines and equipment.
Students and employees can access through the organization’s local area networks (LAN) or through their own personal computers.
Another way to access the Internet is through Internet Service Provider (ISP).

To access the Internet, an existing network need to pay a small registration fee and agree to certain standards based on the TCP/IP (Transmission Control Protocol/Internet Protocol) reference model.
Each organization pays for its own networks and its own telephone bills, but those costs usually exist independent of the internet.
The regional Internet companies route and forward all traffic, and the cost is still only that of a local telephone call.

Internet Service Provider (ISP)

A commercial organization with permanent connection to the Internet that sells temporary connections to subscribers.
Examples:
Prodigy, America Online, Microsoft network, AT&T Networks.

An Internet service provider (ISP), also sometimes referred to as an Internet access provider (IAP), is a company that offers its customers access to the Internet.
The ISP connects to its customers using a data transmission technology appropriate for delivering Internet Protocol packets or frames, such as dial-up, DSL, cable modem, wireless or dedicated high-speed interconnects

End User to ISP Connection
ISP employ many technologies for users to connect to their network such as-
Dial-up
DSL ( Digital Subscriber Line)
broadband wireless
Integrated Services Digital Network (ISDN)

Popular Internet Service Providers in India: Airtel, Vodafone, BSNL, Reliance

How to access the Web?

Once you have your Internet connection, then you need special software called a browser to access the Web.
Web browsers are used to connect you to remote computers, open and transfer files, display text and images.
Web browsers are specialized programs.
Examples of Web browser: Netscape Navigator (Navigator) and Internet Explorer.

Client/Server Structure of the Web

Web is a collection of files that reside on computers, called Web servers, that are located all over the world and are connected to each other through the Internet.
When you use your Internet connection to become part of the Web, your computer becomes a Web client in a worldwide client/server network.
A Web browser is the software that you run on your computer to make it work as a web client.

Hypertext Markup Language (HTML)

The public files on the web servers are ordinary text files, much like the files used by word-processing software.
To allow Web browser software to read them, the text must be formatted according to a generally accepted standard.
The standard used on the web is Hypertext markup language (HTML).

HTML uses codes, or tags, to tell the Web browser software how to display the text contained in the document.
For example, a Web browser reading the following line of text:
A Review of the BookWind Instruments of the 18th Century
recognizes the and tags as instructions to display the entire line of text in bold and the and tags as instructions to display the text enclosed by those tags in italics.

Addresses on the Web:IP Addressing

Each computer on the internet does have a unique identification number, called an IP (Internet Protocol) address.
The IP addressing system currently in use on the Internet uses a four-part number.
Each part of the address is a number ranging from 0 to 255, and each part is separated from the previous part by period,
For example, 106.29.242.17

The combination of the four IP address parts provides 4.2 billion possible addresses (256 x 256 x 256 x 256).
This number seemed adequate until 1998.
Members of various Internet task forces are working to develop an alternate addressing system that will accommodate the projected growth.
However, all of their working solutions require extensive hardware and software changes throughout the Internet.

Domain Name Addressing

Most web browsers do not use the IP address t locate Web sites and individual pages.
They use domain name addressing.
A domain name is a unique name associated with a specific IP address by a program that runs on an Internet host computer.
This program, which coordinates the IP addresses and domain names for all computers attached to it, is called DNS (Domain Name System ) software.
The host computer that runs this software is called a domain name server.

Domain names can include any number of parts separated by periods, however most domain names currently in use have only three or four parts.
Domain names follow hierarchical model that you can follow from top to bottom if you read the name from the right to the left.
For example, the domain name gsb.uchicago.edu is the computer connected to the Internet at the Graduate School of Business (gsb), which is an academic unit of the University of Chicago (uchicago), which is an educational institution (edu).
No other computer on the Internet has the same domain name.

Uniform Resource Locators

The IP address and the domain name each identify a particular computer on the Internet.
However, they do not indicate where a Web page’s HTML document resides on that computer.
To identify a Web pages exact location, Web browsers rely on Uniform Resource Locator (URL).
URL is a four-part addressing scheme that tells the Web browser:
What transfer protocol to use for transporting the file
The domain name of the computer on which the file resides
The pathname of the folder or directory on the computer on which the file resides
The name of the file

Structure of a Uniform Resource Locators

http://www.chicagosymphony.org/civicconcerts/index.htm

http: Protocol
www.chicagosymphony.org: Domain Name
civicconcerts: Pathname
index.htm: Filename

HTTP

The transfer protocol is the set of rules that the computers use to move files from one computer to another on the Internet.
The most common transfer protocol used on the Internet is the Hypertext Transfer Protocol (HTTP).
Two other protocols that you can use on the Internet are the File Transfer Protocol (FTP) and the Telnet Protocol

How to find information on the Web?

A number of search tools have been developed and available to you on certain Web sites that provide search services to help you find information.
Examples:
Yahoo  www.yahoo.com
Excite  www.excite.com
Lycos  www.lycos.com
AltaVista  www/alta-vista.com
MSN WebSearch  www.search.msn.com

You can find information by two basic means.
Search by Topic and Search by keywords.
Some search services offer both methods, others only one.
Yahoo offers both.
Search by Topic
You can navigate through topic lists
Search by keywords
You can navigate by entering a keyword or phase into a search text box.

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