After completing this Chapter, the student will be able to:
explain the basics of the Internet and its origin,
describe functioning of the
give examples of Internet services,
write terminologies of the Internet,
list various usage of the Internet,
illustrate how to surf different websites,
demonstrate how to download files,
• open an e-mail account,
send and receive emails through an email account and
store and retrieve addresses from the address book.
The Internet is based on a layered, end-to-end model that allows people at each level of the network to innovate free of any central control. By placing intelligence at the edges rather than control in the middle of the network, the Internet has created a platform for innovation.
Widely known as a "Father of the Internet," co-designer of TCP/IP protocols and basic architecture of the Internet
Guess how is it possible to see the latest news, cricket, talk to our friend, check availability of railway reservation, timings or status of a particular flight, send or receive mails/messages as and when we wish to. Yes, it is possible through the Internet, where all this happens like magic on few clicks of the mouse. Millions of people across the globe are able to communicate and interact with each other through the Internet. All we need for this is an Internet connection on any computing device like Desktop, Palmtop, Laptop, Mobile Phone, etc. Applications of the Internet have covered almost every field √ be it education, research, entertainment, communication, science, commerce, shopping, advertising and many more.
The Internet is possible because of the ability to interact and share information between the computers connected through a network. The Internet is often called the Network of Networks (Figure 7.1) which enables us to interact and communicate with each other.
Figure 7.1 : Network of networks
7.1 HISTORY OF THE INTERNET
The Internet was not developed within a period of a few days or a few months. Rather, it is the result of a long and aggressive research which took many years.
In 1969, the American Department of Defense (DOD) started a network of devices called ARPANET (Advanced Research Projects Administration Network) with one computer in California and three in Utah. In September 1969, the University of California at Los Angeles (UCLA), the Stanford Research Institute (SRI), the University of California, Santa Barbara (USCB) and the University of Utah were connected by a network that was called the ARPANET. As the use of the network gradually increased, other universities, research organisations, and private and commercial organisations also started using this technology.
The Internet, often referred to as the «Net», consists of a complex network of computers connected by high-speed communication technologies like satellites, microwave devices, etc. It allows easy and quick access to a huge amount of information/resources stored at many different locations around the world. The actual term ≈InternetΔ was finally coined in 1995 by the FNC (Federal Networking Council,USA).
7.2 HOW THE INTERNET FUNCTIONS?
A corporate network may have its computers connected through a local area network, governed by certain rules. Further, this network may be connected with other networks. But, if different networks are governed by different rules, will they be able to communicate with one another? Imagine a group of people having one Tamilian, one Bengali, one Himachali, one Mizo and one from Maharashtra trying to communicate with each other in their own native languages, failing to understand what the other person is trying to say. Therefore, to communicate with each other, some common standard must be followed.
Functioning of the Internet is not controlled by any one particular organisation. It is managed by a group of voluntary organisations. These voluntary organisations have formed the Internet Society. They decide on the rules, known as protocols, for communication over the Internet. The different networks may have their own rules that they follow internally, but when they communicate with each other, they must follow some common rules. It»s like we speaking our mother tongue at home, but while communicating in a mixed group, we use a common language, mainly, Hindi or English.
7.3 HOW TO WORK WITH THE INTERNET?
In order to work with the Internet we need to know certain related terms like www, web browsers, web pages, websites, etc. We should know how to get connected to the Internet. Once connected √ how to use it.
Most of the terms on the Internet are prefixed with the term web. The electronic pages seen on the Internet are known as web pages. A web page can be defined as the document that we see on the Internet. Many web pages linked with each other combine to form a website. A web page can be written in the language known as HTML (Hyper Text Markup Language). HTML is a very simple language having a number of options to represent text. Many other scripting languages have now been developed which can be embedded into HTML, giving it the power to interact with the users. (These are discussed in detail in the next Unit). These dynamic web pages can take inputs from users and give information accordingly √ taking in the location of the user before displaying the weather forecast. For example, a protocol called Hyper Text Transfer Protocol (HTTP) is used to transmit and receive the web pages.
7.3.1 WEB BROWSERS
The web is a collection of a huge amount of information. Every single web page consists of some information and also a number of links, which connects us to other related web pages. To visit the linked web pages, just click over the linked text and the next web page 165
Just like a word processing application is needed to open a word processor document, an application is needed to view an HTML document. To view a web page we need special software called web browser. Mosaic was the first web browser developed by National Centre for Supercomputing Application (NCSA). This browser didn»t have any special features like present day web browsers. It was not possible to view pictures or use any present day font formatting features in the web pages. Initially, the browsers were designed to show plain text, without any formatting.
With the increasing use, the need to incorporate additional features like text formatting, viewing images, playing sound, etc. was felt. Most modern day browsers incorporate all these features. Some other commonly used browsers are Netscape Navigator, Mozilla FireFox, Opera, Safari, MSIE (Microsoft Internet Explorer), etc. Almost all of these support a common set of rules of the language. Some browsers are shown in figure 7.2.
7.3.2 WWW (WORLD WIDE WEB)
One Internet application that is currently drawing a lot of attention is the World Wide Web (WWW), also known as W3. WWW is a hypermedia based software technology allowing consolidation of hypertext, graphics, audio, video and multimedia to provide information on almost each and every topic/subject/area.
WWW was started in 1989 at CERN (European Center for Nuclear Research). The motivation was the need to interact with each other by the group of researchers at far off places. This demand for interaction and communication led to the rapid growth in this area of communication.
Any website located on the Internet has an address associated with it indicating the location of the website. Every page has an address associated with it. This address is known as the URL.
7.3.3 URL (UNIFORM RESOURCE LOCATOR)
URL stands for Uniform Resource Locator. Every web page that is displayed on the Internet has a specific address associated with it. This address is known as the URL. It tells us the location of the web page being displayed and other related information.
As the postal address is required to reach a letter to a person staying anywhere on earth, a unique location (address) of a web element which may be a website or a web page is required in the World Wide Web to view it in the browser. This unique address of the web elements is referred to as a URL. The URL consists of four basic parts, namely, server type, hostname, folder name and the filename. Each one of these has a specific function. The ≈server typeΔ indicates the type of Internet server (Protocol) being accessed. The server type is always followed by ≈://Δ and the host name. The host name is the Internet address of a remote computer on which the files reside. The folder name indicates the name of the directory in which the files are located. The filename specifies the name of the specific document to be displayed in the browser. The filename itself consists of two pieces of information, the name of the file to be displayed and the file extension, which specifies the file type (.htm for HTML file, .txt for a text file, .bmp for a bitmap image, etc.)
The structure of a URL can be represented as follows:
A URL is illustrated in figure 7.3.
Many other protocols exist apart from http. Table 7.1 lists some common protocols.
ftp File Transfer Protocol is used to transfer binary and text files over the Internet
file Local file
news News group /News article
telnet For remote login over a TCP/IP connection
TCP/IP Transmission Control Protocol Internet Protocol. TCP/IP consists of a set of two protocols i.e. Transfer Control Protocol and Internet Protocol. Transfer Control Protocol controls the flow of data and is a reliable service protocol. Every computer in a network has a unique IP address associated with it. IP identifies and reach the target computer on the network.
UDP User Datagram Packet is used to transfer data between two computers. It is an unreliable protocol, offering no guarantee for data delivery.
There are other protocols also like SLIP (Serial Line Internet
Protocol), SMTP (Simple Mail Transfer Protocol) ARP (Address Resolution
Protocol) PPP (Point to Point Protocol), etc.
7.3.4 CONNECTINGTO THE INTERNET
In order to activate Internet services on any computer, it requires an
Internet connection from an Internet Service Provider. There are several Internet Service Providers (ISPs) in India like VSNL, BSNL, Airtel, Reliance, etc. They charge some nominal fee for installation and connection. Depending on the requirement we can get an Internet connection in any of the following ways:
1. Dial-up connection : We can get connected to the Internet by dialing the ISP»s number. This is useful if the network is either confined to small group of computers or for a single PC (Figure 7.4).
2. Leased lines : A dedicated line Figure 7.4 : Set up for Internet connection is laid specifically for the connection. This provides a fairly high speed, but is
expensive. This is suitable for an organisation requiring uninterrupted, high speed Internet connection.
3. Broadband : This also provides a good speed. While leased line requires a separate telephone line, broadband can be delivered using an existing telephone line. This is ideal for home and small businesses requiring high speed Internet.
WiFi Broadband : These days even wireless connections are available. For this we need to have a Wi Fi card attached to the computer and a wireless modem.
When we connect to the Internet we must know its speed parameters. The speed of the Internet is measured in the number of bits transferred per unit time. Generally, the speed of the Internet is measured in kbps (kilo bits per second), but these days some organisations are providing high speed connections in Mbps (Mega bits per second).
Bandwidth : In context of the Internet, the number of bits transferred by a channel per unit time is the bandwidth.
In order to have a connection we need a device called the modem. This device converts the digital signal from the computer into an analogue signal that can travel through the telephone line. On the other end, this analogue signal is again converted back to digital form by the modem at the destination end. Some computer systems have internal modems (built-in within the motherboard) while in some systems there might be a need to have an external modem to have an Internet connection.
Another device called a router can be attached to the computer to access the Internet. The router is a device used for connecting two different networks.
7.3.5 DOMAIN NAMES
All the websites on the Internet have unique names associated with them. To launch a website, we must have a unique domain name. In order to avoid any conflict within the names of the websites the concept of domain names was developed.
There are certain websites which have .ac which indicates academic organisations, .in suffixed to their name indicating that they belong to India, for example: , , and many more. websites having .au as a suffix indicate Australia, .jp indicates Japan and so on. However, there is no such suffix for USA.
A domain can be generic or according to the names of the country. Some common domain names are:
in √ stands for India (country name)
gov √ indicates government agencies
net √ network organisations
org √ non-profit organisations
edu √ educational organisations
com √ commercial organisations
mil √ military or defence
7.4 USES OF THE INTERNET
The Internet is extensively used for a wide variety of purposes. Some of these are mentioned below:
7.4.1 SEARCH FOR INFORMATION
A number of programs called search engines are available to search for the information on any topic. Some famous search engines are provided by: , wikipedia.com, webopedia.com, MSN.com, Yahoo.com, etc.
A search engine is a complex program that searches documents containing a specified set of keywords. A search engine basically works in three phases:
The search engine sends a program (called the spider) that searches the web pages in the Internet for the keyword.
After the spider fetches the result, another software called the indexer reads these results. The indexer then creates an index based on the words contained in each of the documents returned by the spider.
After indexing, the search engine presents only the documents matching the search criteria to the user.
The relevance of the result returned by the search engine depends on how you frame the query. To search any information, connect to any of the searchengine websites like: , , , and follow the points mentioned below:
Enter the keywords of the topic for which the search is required in the input box. For example, if a search is required on population then enter the keyword as ≈PopulationΔ or ≈populationΔ
Search for the phrase is done by entering the phrase within the double quotes. For example, if the search is required on declining sex ratio then the keywords can be entered as: ≈declining sex ratio.Δ
Notice that the phrase to be searched has been given in double quotes. If double quotes are not entered then search will be made for individual keywords. Any document containing any one of the keywords will be returned.
The search can be made simultaneously for more than one word by placing a space or «OR» within the keywords.
If a search is to be made for a set of words in a desired sequence then these set of keywords can be given in double quotes.
7.4.2 E-MAIL (ELECTRONIC MAIL) SERVICES
The Internet is commonly used for sending and receiving e-mails. We can send a message electronically to any person on the globe, provided that person has an e-mail-id. This service is fast and economical.
Chatting involves textual exchange of message in real time. Chat servers provide facility to create virtual chat rooms and only the members associated with these rooms are allowed to share messages. Chat works best if the time is scheduled by both the parties who are willing to chat √ as both the parties must be connected to the Internet while chatting. Some common chat engines are : Yahoo Messenger, Google Talk, Rediff Bol, etc.
7.4.4 INSTANT MESSENGER SERVICES
These tools can be used to send messages instantly. It also allows us to talk to anyone anywhere in the world. This is a cheaper and quicker method compared to other services. Unlike chatting, it is not necessary to have an account with the same provider. Additionally, both the users need not be connected while sending messages. We can easily download the messenger software from Internet e.g. MSN Messenger, Yahoo Messenger, etc.
Newsgroup is an e-service hosted by many newsgroup organisations. One can become a member of a newsgroup and read and share current affairs and messages. Newsgroups cover a broad domain of interests including education, science and technology, medicine, arts, sports, etc. USENET is one such example.
People can have a conference or meeting sitting at different locations with a microphone attached to their computers.
In teleconferencing we are able to talk to each other sitting at different places but in video-conferencing we can also see what is happening at the other side. We have observed that the anchor, panelists and experts sitting at different locations across the globe communicate and share their views in many news channels. For this, we need a web-camera and a microphone connected to the computer system, high bandwidth connection, and video-conferencing software.
E-commerce or Electronic-Commerce means online transactions of business. In this, the vendor and customer conduct a transaction sitting at different geographical locations, connected through the Internet. The customer need not strain himself by visiting a number of shops outside in scorching heat or heavy rains. He can do shopping by sitting at home, visiting the desired e-commerce site and placing an order
online. E.g. , , http:/ /shopping.rediff.com, etc.
It is an acronym for mobile commerce. It is an upcoming technology after e-commerce. It involves buying and selling of goods and services electronically through wireless handheld devices at any place. We can do transactions through our mobile phones also.
7.5 HOW TO MANAGE AN E-MAIL ACCOUNT
7.5.1 E-MAIL ADDRESS
An e-mail addess (account) consists of two main parts, the username and the domain-server name with the symbol @ in between.