14

Internet

1. What is Internet? Discuss its evolution.

Ans.: The word ‘Internet’ is derived from two words: interconnection and networks. It is also referred to as ‘the Net’. Internet is a worldwide system of computer networks, that is, a network of networks, which allows the participants (users) to share information. It consists of thousands of separately administered networks of various sizes and types. Each of these networks comprises tens of thousands of computers. Moreover, the total number of users of the Internet is known to be in millions. This high level of connectivity encourages an unparalleled degree of communication, resource sharing, and information access. It is probably the most powerful and important technological advancement since the introduction of the desktop computer.

The foundation of Internet was laid in 1969 by the Department of Defence (DoD) of United States of America. They wanted to create a computer network that could continue to function in the event of a disaster, such as a nuclear war. Even if a part of the network was damaged or destroyed, the rest of the system would continue to work. That network was known as ARPANET (Advanced Research Projects Agency Network), which linked US scientific and academic researchers. It was the forerunner of today's Internet. Later in 1980, another agency, the National Science Foundation (NSF) created a new network of computers based on ARPANET, called NSFNET, which turned out to be more efficient and capable. Initially, NSFNET was designed to link five supercomputers situated at the major universities of NSF and allowed only academic research. Over the time, this network expanded to include sites for business, universities, government, etc. and finally becoming a network consisting of millions of computers, now known as the Internet.

In the 1980s, Usenet newsgroups and electronic mail (e-mail) came into picture. To keep track of the information on the Internet, indices such as Archie and the wide area information server (WAIS) were also created in this decade. To give users an easy-to-use interface to work with, the University of Minnesota created Gopher, a simple menu-driven system for accessing files. Internet really became popular in the 1990s after the development of the World Wide Web (WWW). Before that, it was open for a handful of sites only. It is amazing that as recently as June 1993, there were only 130 websites, but now there are millions.

With the growth of the Internet, the quality, quantity, and variety of information also grew. The Internet today is a repository of every type of information. Nowadays, an Internet user can get all sorts of information ranging from how to add to the design of a functional spaceship to choosing a product for personal use.

2. List various uses of Internet.

Ans.: Internet connects us with the outside world as it can be used for sharing files, communication with other people, entertainment, and many more. Some common uses of the Internet are discussed as follows:

	Information retrieval: It is one of the biggest pools of information that has ever existed. It provides the latest information on any desired topic such as science, politics, travel, sports, cooking recipes, etc. It also provides you with the latest news about various issues, events and happenings, new developments and inventions, disasters, etc. It is a reliable, immediate, convenient, and fast source of information, which brings the information to you that you might otherwise have to pay for it or find it out by less convenient means.
	Communication: It is also widely used for communication purposes. It offers an economic and easy alternative to traditional methods of correspondence. You can communicate with other people using a variety of communication features like chatting, e-mail, videoconferencing, newsgroups, etc. provided on the Internet. It has helped people to reach out and communicate with others at distant places in real time. For communication, it is used by connecting with each other through various instant messenger services like Gtalk, Skype, and Yahoo messenger. Also, people can connect with each other through social networking sites like Facebook, Google plus, etc.
	Entertainment: It is widely used for entertainment also by providing a wide range of options like online audio and video libraries, online gaming, etc. Nowadays, companies working in media and entertainment field are widely using the Internet to broadcast the recorded and live TV and radio programs.
	Online business: The individuals, companies, and business organization use the Internet for carrying out business online. The activity of carrying out business over the Internet is known as e-commerce. It includes advertising, selling, buying, distributing products, and even providing after-sale services to the users. E-commerce reduces the cost and time of people that they incur while going out for shopping.
	Online education: Online education is the current topic among students who avail this facility as there are many websites offering online courses like designing, programs, or subjects.

3. Explain how Internet is different from local area network (LAN)?

Ans.: Internet and LAN are often assumed as similar, but there are many differences between LAN and Internet. They are listed in Table 14.1.

Table 14.1 Differences Between LAN and Internet

 

S. No.	LAN	Internet
1.	It is a computer network that covers only a small geographical area (usually within a square mile or less) such as an office, home, or building.	It is a network of millions of networks connecting computers worldwide.
2.	It is a private and local network.	It is a public and global network.
3.	A computer in LAN can access only the computers within that network.	A computer can access web pages, software, and services openly on any other computer in the Internet.
4.	The network in LAN is established through Ethernet cable or radio waves.	Millions of networks in Internet are linked through telephone lines, satellites links, or other long-range communications technologies.

 

4. Write a note on World Wide Web.

Ans.: The World Wide Web (abbreviated as the Web or WWW) is a collection of linked documents or pages stored on millions of computers, and distributed across the world. The concept of the Web began at CERN (the European Center for Nuclear Research) Geneva, Switzerland in the year 1989. Since then, it is the most popularly used Internet sub-network. One of the main reasons that led to its popularity is that it provides information in multimedia form, that is, in more than one medium such as text, graphics, video, and audio. Further, it provides a simple and consistent way of accessing the information available on the Internet by using hypertext system. In hypertext system, the documents are connected to other related documents on the Internet through links. The web uses a specific Internet protocol called hypertext transfer protocol (HTTP) to support hypertext documents. There are many characteristics that have made WWW the most popular Internet facility. Some of them are as follows.

	It provides an easy-to-use and interactive user interface by making use of hyperlinks, textboxes, checkboxes, images, etc.
	It can contain any kind of information such as text, images, audio, and video.
	It also provides a simple and consistent way of accessing the information available on the Internet either by clicking on a hyperlink or by entering a specific address.

5. Define the following terms:

(a) Web page

(b) Website

(c) Home page

Ans.:  (a) Web page: The hypertext documents on the Web are known as web pages. It is written in a language called HTML (Hypertext Markup Language) that enables to embed hypertext links in the document. Using these hyperlinks, a user can jump from one web page to another.

(b) Website: It is a set of related web pages (linked through hypertext links), published by an organization or an individual. Typically, it contains a home page along with other additional web pages. Each website is accessed by its own address known as URL (Uniform Resource Locator). All the websites on the Internet constitute the WWW.

(c) Home page: When a user browses the WWW, he/she will often see the term ‘home page’. A home page (also called as index page) is the starting point or a doorway to the website. It refers to the web page that identifies a website and contains the hyperlinks to other web pages in the website. It may contain links to other websites also. Like the table of contents of a book, the home page usually provides an overview of what could be found in the website. If there is not much information, the home page may be the only page of the website. However, usually you will find at least a few other pages.

6. What is a web browser?

Ans.: A web browser (or simply called browser) is a special software that enables users to read/view web pages and jump from one web page to another. It is the software that is needed to find, retrieve, view, and send information over the Internet. The most popular browsers are Microsoft Internet Explorer and Netscape Navigator. They are of the following two types:

1. Graphical browsers: They allow retrieval of text, images, audio, and video. Navigation is accomplished by pointing and clicking with a mouse on highlighted words and graphics. Netscape Navigator, Internet Explorer, and Mozilla are graphical browsers.
2. Text browsers: They provide access to the Web in text-only mode. Navigation is accomplished by highlighting emphasized words on the screen with the arrow up and down keys, and then pressing the Enter key to follow the link. Lynx is an example of text-based browser.

7. List various features of a web browser.

Ans.: There are many web browsers available having different features. However, every browser shares some of the basic features mentioned below:

	It handles requests for HTML files, interprets links, and deals with embedded images, audio, and video elements.
	It keeps the history of the websites visited.
	It lets a user to save a collection of pages, allowing for later retrieval.
	It provides a row of buttons at the top of the browser window for browsing the Internet conveniently.
	It connects to an e-mail program for importing favourites/bookmarks and sending and receiving e-mails from the most commonly used applications and formats.
	It supports Web standards currently in use such as HTML, HTTP, JavaScript, and Unicode.
	It supports multimedia data in three ways: Native support: A browser supports some of the image formats natively. In other words, it presents the image as a part of the web page in the browser window. Plug-in: It is a program that adds functions to the web browser, such as an audio player or a compression utility. It is a set-up within the browser through which it functions properly and correctly. Helper programs: These programs are external applications launched by a web browser or Internet client program to view non-native file formats and data types. They are not integrated with the browser.

8. How does the Internet work?

Ans.: Internet is not a single network but is a network of networks. All these networks, inspite of their similarities and dissimilarities in terms of architecture, are connected to each other through gateways. A gateway is a device that connects two or more networks which are dissimilar in terms of the architecture and the protocols they use.

Within a network, the information flows from one computer to another over the network. The computer that is sending the information is known as the source computer and the one receiving the information is known as the destination computer. The sequence of actions that take place during communication between the source and the destination computer are as follows:

1. At the source computer, the information to be sent is broken into small packets. Each packet is then assigned a unique serial number such as 1, 2, 3 and so on.
2. The packets are then sent to the destination computer.
3. The packets are received at the destination computer and they may arrive in a random order, that is, packet 4 may arrive before packet 1.
4. The packets are reassembled to obtain the original information. Note that the packets are reassembled according to their serial number and not in the order of their arrival.

9. Define protocol. Briefly discuss different protocols available on the Internet.

Ans.: The communication between different computers is possible by using a protocol that offers a standard format and method for communication. A protocol is a formal set of rules and conventions that governs how computers exchange information over a network medium. A wide variety of protocols are available on the Internet. However, some of the commonly used protocols include TCP, IP, FTP, HTTP, SMTP, and NNTP.

TCP/IP

It stands for Transmission Control Protocol/Internet Protocol. It is the suite of communication protocols that is used as a standard for transmitting data over the Internet. It consists of two protocols: TCP and IP. TCP is responsible for dividing the message into small packets at the source computer that are transmitted to the destination computer over the network. At the destination computer, it reassembles the packets into original message. It ensures a reliable and ordered delivery of packets. If any packet is lost during the transmission, it requests the packet to be resent. Moreover, each packet received by the destination computer is acknowledged by the source computer. On the other hand, IP is the network protocol essential to use the Internet. It is responsible for routing the packets to their desired destination. The physical connections over the network are not made by IP as it is used in conjunction with the other protocols that are responsible for creating connections.

FTP

It stands for File Transfer Protocol. It is used to transfer files or folders from one system to another on the Internet. It allows the user to access the files stored in the directory of a remote computer that is connected to the Internet. Using FTP, one can upload and download files from the remote computer, if he/she has access permission on the remote machine. Though files can be transferred using e-mail, this is not a good choice if the file size is large or when there are many files. FTP is discussed in detail in Q20.

HTTP

It stands for Hypertext Transfer Protocol. It is the Internet protocol responsible for transferring and displaying web pages. It provides a way for web clients and web servers to communicate with each other by sending messages. HTTP is discussed in detail in Q18.

SMTP

It stands for Simple Mail Transfer Protocol. It is a mail protocol used for sending/receiving e-mails from one computer to another via the Internet. It handles the transfer of messages between the sender and the receiver. During the message exchange, it is used twice. Once, it is used to transfer the mail from sender's end to sender's mail server, and then to transfer the mail from sender's mail server to receiver's mail server. However, to retrieve the mail from receiver's mail server at the receiver's end, a different mail protocol such as POP3 and IMAP is used.

NNTP

It stands for Network News Transfer Protocol. It is used to transfer news messages over the Internet. The NNTP server is a computer that collects a copy of news messages from the newsgroups and allows users to read these messages. It also allows users to send their messages to the same groups.

10. What is a URL? Discuss the typical structure of a URL.

Ans.: Each web page has a unique address called URL that identifies its location on the Internet. Usually, the structure of a URL consists of four parts: protocol, web server (or domain name), path, and file name. For example, the different parts of the URL http://www.up.nic.in/tutor/start/main.htm are as follows (Figure 14.1):

	Protocol: http
	Web server name/domain name: www.up.nic.in
	Path: tutor/start/
	File name: main.htm

The first part of the address, the part before the colon, is the protocol. Mostly, the HTTP is used for accessing a web page. Apart from HTTP, you could also find other protocols such as FTP, news (news server), and telnet (for accessing remote computers). After the protocol, comes the domain name. The protocol and the domain name are separated by colons and slashes.

Figure 14.1 Uniform Resource Locator

A domain name is a unique name that identifies a particular website and represents the name of the server where the web pages reside. They are the human-readable addresses and hence are easier to remember. They have two or more parts separated by dots. The letters occurring after the dot (.) identify the domain type. A domain type represents the type of organization or countries to which the web server (sometimes called host computer) belongs.

Dozens of domain types have been assigned to identify and locate files stored on host computers in countries across the world. These are referred to as two-letter Internet country codes, and have been standardized by the International Standards Organization (ISO): for example, uk for the United Kingdom, de for Germany, au for Australia, and in for India. The last part of a URL consists of the path and the file name. Path name specifies the hierarchic location of the said file on the computer. For instance, in http://www.up.nic.in/tutor/start/main.htm, the file main.htm is located in start, which is a subdirectory of tutor.

11. What is a hypertext?

Ans.: A hypertext is a system that provides a simple and consistent way to organize large data (that includes text, images, pictures videos, etc.) available on the Internet. In hypertext systems, the documents contain links to other related documents on the Internet. These links are called hyperlinks, hotlink, or simply links. It is used to jump to another part of the same page or to load a different web page. Usually, it appears in a different colour (typically in blue and underlined) from the rest of the text. When the cursor is moved over a text link or over a graphic link, it will change from an arrow to a hand. The hypertext words often provide a hint about the connected page. When the user returns to a page with a link he/she had already visited, the hypertext words will often be in a different colour (usually magenta), indicating that the link has already been used. However, the user can certainly use that link again.

12. Differentiate between the following:

(a) Download and upload

(b) Online and offline

Ans.:  (a) Download and Upload: Download refers to the act of transmitting data from a remote computer on the Internet or other network to one's own computer. When the user downloads a file, he/she is actually copying a particular file from the remote computer and placing it on his/her hard drive. Downloading allows a user to save file for later use thereby reduces the time spent online and the corresponding charges.

Upload is just the opposite of download. It refers to the act of transmitting data from local computer to any other computer on the Internet or network. For example, a software company may upload a demonstration of its new software onto the Web so that users can then download the software.

(b) Online and Offline: The term ‘online’ is commonly referred to the state of being connected to the networked computer system or the Internet. For example, if you are browsing the WWW, your computer is said to be online. Being online also refers to any peripheral device (like printer) that is connected to the system and ready to use.

Offline is just the opposite of online. It refers to the state of not being connected to the remote computer or the Internet. A printer or other peripheral that is not ready to use is also considered offline.

13. What do you mean by an ISP? What type of connections does the ISP provide?

Ans.: An Internet service provider (ISP) is an organization that connects its subscribers’ computer using modem to the Internet. The connections can be provided by telephone lines, cable lines, or a wireless one. In order to use the Internet connection, the user has to first log on to the host computer using the username and password provided by the ISP. Some of the well-known ISPs are America Online (AOL), Microsoft Network (MSN), VSNL, etc.

It provides different types of connections based on many aspects like hardware used, speed of the connection, etc. Some of the connections available for the users these days are described as follows:

	Dial-up: It is the access method that uses telephone lines to connect to the Internet. It is the most common way for individuals who use home computers to connect to the Internet. To connect to the Internet by using dial-up, the user needs to specify a username, a password, and a telephone number. After the connection is established, the user can start browsing sites on the Internet.
	ISDN: It stands for Integrated Services Digital Network and is more common in business and commercial use. It was the first high-speed alternative to regular analog phone modems. It involves the digitization of telephone network so that voice, graphics, text, and other data can be provided to users from a single terminal over existing telephone wiring. Digital connections have fewer errors in transmission, which means the speed of downloading graphics, web pages, sound, etc. is increased to four times faster than with dial-up modems.
	Cable modem: It connects the user to the Internet through a cable television line. Nowadays, many cable companies offer Internet along with television accessibility. A cable modem will typically have two connections: one to the television outlet and the other to the computer. It not only provides a faster Internet access (10–100 times as fast as the dial-up modem), but interactivity to the television also.
	Leased line: This facility provides reliable, high-speed Internet access ranging from 2.4 Kbps to 45 Mbps. A leased line connection is an affordable way to link two or more sites for a fixed monthly charge. Usually, its facility can be provided via fibre-optic or copper lines. It provides a consistent amount of bandwidth and is an excellent way to provide data, voice, and video links between sites.
	DSL: It stands for Digital Subscriber Line. It is provided through an existing phone line, but it works differently than regular analog modem dial-up access. It operates over normal telephone lines and it can be used simultaneously with the telephone. It can increase the connection speed by as much as ten-fold from a standard dial-up modem.
	Broadband: This type of access is good for remote locations, where ISDN, cable, or DSL are not available. It gives a decent download speed, but to upload data, the user still needs a regular analog modem to dial in, via a phone line. Satellite connection can be either a two-way service or a one-way service. In case of two-way satellite service, the data are transmitted via satellite to a dish antenna at the user's house. In one-way system, the user needs a conventional modem and telephone link to an ISP. Satellite connection is expensive but sometimes is the only fast option for people who are beyond the service area of cable and DSL providers.

14. List some factors that should be considered while selecting an ISP.

Ans.: While choosing an ISP, many factors should be kept in mind for subscribing. These factors are listed as follows:

	The user should check the speed and consistency of the Internet access.
	The user should also check the ISP's reliability, that is, whether it provides consistent access to the Internet or does it have frequent down times.
	The price of the ISP and other additional services provided by it should also be considered. For example, many ISPs provide free web space so that users can create their own website, free e-mail address, and much more.
	The user should also check whether the ISP provides a round-the-clock technical assistance.

15. Differentiate between dial-up and broadband Internet connectivity.

Ans.: There exist many differences between dial-up and broadband connections based on their structure and functions. These differences are discussed in Table 14.2.

Table 14.2 Differences Between Dial-up and Broadband Interconnections

 

S. No.	Dial-up Connection	Broadband Connection
1.	It can be made using telephone lines only.	It can be made using telephone line, cable, and satellite.
2.	The maximum speed offered by this connection is 56 Kbps.	The maximum speed offered by this connection is 256 Kbps.
3.	The phone line used in the connection is engaged while you are connected to the Internet.	In this type of connection, the phone line and the Internet connection can be used simultaneously.
4.	It uses a built-in modem for the connection.	It needs a separate modem or router to establish the connection.

 

16. When a user should prefer a dial-up connection for connecting to the Internet? Also, describe the requirement for choosing high-speed connections.

Ans.: If the user wants the Internet mainly for sending e-mail, occasional chats, and infrequent browsing, then he/she should work with regular modem dial-up access. In this case, the user should invest in a good quality 56 Kbps modem and a good ISP. However, if the user is using the Internet frequently for research, downloading or uploading a fair amount of data, to play multi-player games, or to use the Internet's multimedia capabilities like live audio or video streaming, then he/she should look into other high-speed accesses such as cable modem or ISDN.

17. What are the basic requirements for getting connected to the Internet?

Ans.: To connect to the Internet, some basic requirements are needed. These requirements are discussed as follows:

Computer: The computer system must have at least 386-microprocessor chip with a minimum of 16 MB of RAM. For a good browsing experience, use a faster chip (Pentium III/Pentium IV) with more RAM (128/256 MB). In addition, a colour monitor, with at least 640 × 480 resolution and a capability of displaying a minimum of 256 colours, is also vital. It should also possess a hard disk, with at least 200 MB of free space, to store Internet software and temporary Internet files. Since the Web is a multimedia medium, one can also enjoy sound on his/her system with a sound card and a pair of speakers.

Modem: Apart from the previously mentioned configuration, a computer system must have a device named modem, which enables a computer to transmit data over telephone lines. A modem (acronym for modulator–demodulator) is a hardware, which converts digital data into analog signals (i.e., modulation) that can be sent over an analog telephone line and convert the analog signal back into digital data (i.e., demodulation). Thus, when the modem receives the data from a web server via phone system, it reconstitutes the analog signal into digital form so that the computer can understand it. The most critical aspect of the modem is its speed of operation. The speed of modem is measured in kilobits per second (Kbps). Modern modem supports 28–56 Kbps speeds. Modems are of two types: Internal modem: It is a card that is fitted inside the computer with a lead running directly from the computer to the phone socket. External modem: It is a small external box wired between the computer and the phone socket.

Internet connection: Before connecting to the Internet, one needs to buy an Internet connection from an authorized ISP. The speed of accessing the Internet entirely depends upon the type of connection you buy from the ISP. The type of Internet connections available today have already been discussed in Q13.

Internet software: To connect to the Internet, a computer requires mainly three different kinds of software: TCP/IP: It is the basic communication protocol of the Internet allowing programs on user's computer to communicate over the Internet. Dialer software: It is provided by the ISP to instruct the modem to dial the phone number and to identify the user's machine to the access provider's system for access to the network. Browser: To use the Internet, a web browser is essential that allows the user to view the information available on the WWW.

18. Write a short note on HTTP.

Ans.: HTTP is the Internet protocol responsible for transferring and displaying web pages. It has been designed especially for the WWW at CERN. As it is an Internet protocol for a specific application, it rides at the top of the stack of protocols that make up the Internet. When HTTP link is traversed, the browser will connect to the appropriate machine, retrieve the document, and close the connection. The HTTP server will tell the browser about the type of document it is sending so that the browser at the client side can display it correctly.

It provides a way for web clients to communicate with one another, primarily through the exchange of messages from clients and servers. The message types for HTTP are classified in four parts:

1. Connection: This type of message occurs when a client tries to connect to a specific web server and displays a Connecting to HTTP server message. If the client cannot make the connection, the attempt will usually time out and the browser displays a Connection timed out message.
2. Request: This is where the client asks for the web resource it is looking for. This includes the protocol to be used, the name of the object to be provided, and information about how the server should respond to the client.
3. Response: If the server can deliver the requested object, it responds in the manner requested by the client to deliver the necessary data. If it cannot deliver, it sends an error message explaining the reason for not delivering the message.
4. Close: After the information has been transferred in response to the request, the connection between the client and the server will be closed.

For example, if a web page contains objects such as movies, sound, or graphics, a client makes a request for each object. A web page containing a background sound and three graphics thus requires five separate server request messages to retrieve the four objects—the background sound and three graphics—and the page in which these objects are referenced. Due to the enormous growth of the number of HTTP users, it has had a tremendous impact on the Internet.

19. Define Intranet.

Ans.: Intranet is a private network that is set up within an organization and also controlled by the organization; nobody outside the organization is permitted to access the network. It utilizes the same protocols as used for accessing the Internet through a web browser. The users of intranet can access the basic services of the Internet such as e-mail. The difference between an Intranet and the Internet is that an Intranet user can view only those websites that are owned and maintained by the organization hosting the Intranet. On the other hand, an Internet user may visit any website without any permission.

20. Explain some applications of the Internet.

Ans.: Today, the Internet has grown from a small network to the biggest network of computers. Due to this colossal growth, it has become the biggest domain of information. Nowadays, an Internet user has access to a wide variety of services such as electronic mail, file transfer, vast information resources, interest group membership, interactive collaboration, multimedia displays, real-time broadcasting, shopping opportunities, and much more.

Electronic Mail

Electronic mail (or e-mail) is a fast, easy, and inexpensive way to communicate with other Internet users around the world. It is one of the basic and earliest services of the Internet and the most used application on the Internet too. It overcomes most of the problems and delays of getting a physical document from one person to another. Rather, it has the dual advantage of not only being faster but cheaper to use as well.

Each user of e-mail has a mailbox address to which messages are sent and the mailbox can be accessed from anywhere and at anytime. It does not matter what type of connectivity the user is having, he/she will always be able to use this service. One can receive and send e-mails from all systems whether it is a Windows PC or a UNIX machine. Not only this, it can also be used to send documents, images, audio, video, etc. as an attachment along with the mail.

FTP

It is a set of rules that enables a user to transfer files from one system to another. It was the first service developed for the Internet so that government and educational institutions could easily exchange files. It allows the user to get access to the files stored in the directory of a remote computer that is connected to the Internet. Using FTP, one can upload and download files from the remote computer (known as FTP servers), if he/she has access permission on the remote machine. Though files can be transferred using e-mail, this is not a good choice if the file size is large or when there are many files. FTP sites can consist of hundreds to thousands of files with information on books, music, software, games, images, sounds, multimedia, course ware, etc. It can be done using the command prompt, browsers, and various GUI-based FTP software such as CuteFTP and WS_FTP.

Telnet

The word ‘telnet’ is derived from telecommunications and network and is a protocol that allows a user to log on to a remote computer. It is also known as remote login, which means connecting one machine to another in such a way that a person may interact with another machine as if it is being used locally. For example, a telnet user in New Delhi could connect to a computer in the New York City Public Library and search the card catalogue the same way as someone located at a terminal in the library. Once connected, the user's computer emulates the remote computer. When the user types in commands, they are executed on the remote computer. The user's monitor displays what is taking place on the remote computer during the telnet session. The user's computer, which initiates the connection, is referred to as the local computer or telnet client, and the machine being connected to, which accepts the connection, is referred to as the remote computer or telnet server.

Internet Relay Chat (IRC)

It is a service on the Internet that allows people to communicate in real time and carry on conversations via the computer with one or more people. It provides the user with the facility to engage in simultaneous (synchronous) online ‘conversations’ with other users from anywhere in the world. Unlike other forms of group communication on the Internet, chat is an instant communication. However, both parties must be connected to the Internet and that too at the same time, running the right software, and actively participating in order to chat.

Generally, the user runs a program (called client) to connect to an IRC server. The server relays information to and from other servers on the same net. Popular IRC client applications are mIRC, Virc, and LeafChat. Once connected to an IRC server on an IRC network, the user will usually join one or more ‘channels’ (also known as chat rooms) and converse with others there. Each channel is devoted to a different topic. Conversations may be public (where everyone in a channel can see what the user types) or private (messages between only two people, who may or may not be on the same channel).

Chatting and Instant Messaging

Chat programs allow users on the Internet to communicate with each other by typing in real time. They are sometimes included as a feature of a website, where users can log into chat rooms to exchange comments and information about the topics addressed on the site. For example, America Online is well known for sponsoring a number of topical chat rooms. Chatting has become one of the ‘killer applications’ of the Internet and has become quite popular with all kinds of Internet users. It is quite cheap to chat online. Although e-mail is also a cheap source of communication, but it is not done on ‘real time’ and the response to the message solely depends on the recipient. Note that even though chatting is based on standardized IRC system, but unlike IRC, the user does not need to have any special software to connect to any chat rooms.

A variation of chat is instant messaging where a user on the Web can contact another user currently logged in and type a conversation. To avail this Internet service, the user must have a software called instant messenger installed on the system. Instant messaging is just as if making a text-only phone call over the Internet, that is, the user is ‘talking’ to the other person (possibly more) instantly. There are various products out there for instant messaging such as MSN Messenger and Yahoo Messenger.

Internet Telephony

Internet telephony is the use of the Internet, rather than the traditional telephone company infrastructure, to exchange spoken or other telephonic information. It consists of hardware and software that enable people to use the Internet as a transmission medium for telephone calls. There are many Internet telephony applications available. Some applications such as CoolTalk and NetMeeting come bundled with popular web browsers.

The required hardware for Internet telephony generally consists of end devices (either traditional telephones or audio-equipped personal computers) and gatekeepers that provide call admission control, bandwidth management, addresses translation, authentication, and user location. They communicate with each other using the Voice over Internet Protocol (VoIP). For the cost of a local connection to their service providers, users can call anywhere in the world. Note that there is no single Internet phone standard at this time. Therefore, participants need to use the same software at each end of the connection.

Videoconferencing

It uses the same technology as IRC, but also provides sound and video pictures. It enables direct face-to-face communication across networks. A videoconferencing system has two or more parties in different locations, which have the ability to communicate using a combination of video, audio, and data. It can be person to person (referred to as point-to-point) or can involve more than two people (referred to as multipoint) and the videoconferencing terminals are often referred to as endpoints.

In this form of meeting, participants in remote locations can view each other and carry on discussions via web cameras, microphones, and other communication tools. The following five elements are common to all videoconferencing endpoints:

1. Web camera: It captures live images to send across the network.
2. Visual display: It displays the images of the people taking part in the videoconference.
3. Audio system: It includes both microphones to capture audio from the endpoint and loudspeakers to play back the audio received from other endpoints across the network connection.
4. Compression: Videos are very bandwidth-intensive and they take a long time to load. Therefore, video systems include technologies, often referred to as codecs, to compress and decompress video and audio data, allowing transmission across a network connection in near real-time.
5. User interface and control system: The user interface allows the users to control interactions, for example, placing calls, storing and locating numbers, and adjusting environment settings such as volume. The control system handles the underlying communication that takes place between endpoints.

Videoconferencing has many benefits, as a tool for both teaching and learning. A key factor is that it provides real-time, visual communication, unlike other communications methods such as e-mail. Videoconferencing technology is still in its infancy, and one of its major limitations is the bandwidth (the volume of information per unit time that a computer or transmission medium can handle) available on the Internet. As the protocols and applications for videoconferencing develop higher resolution and improved speed, participation will increase.

Commerce Through Internet

Today, business is taking place through electronic telecommunication media. Nowadays, various organizations offer the facility of shopping online. This type of business model is known as electronic commerce (or e-commerce). E-commerce refers to buying and selling goods and services online. It integrates communication, data management, and security capabilities, which allow organizations to exchange information about the sales of goods and services. Essentially, it is the end-to-end digital exchange of information needed to conduct business including Electronic Data Interchange (EDI) and Electronic Funds Transfer (EFT). EDI is the computer-to-computer exchange of routine business transactions including payments, information exchange, and purchase order requests. EFT is a technology that allows the transfer of funds from the bank account of one person or organization to that of another.

While discussing about e-commerce, we normally talk about virtual shopping malls, up front store where the user virtually visits and selects the product(s) of his/her choice. After selecting the desired product(s), the payment for the purchase is done. Online payment can be done through credit card. Techniques for cash transactions have also been developed in the form of Internet money such as CyberCash and digital money. After transfer of money, the items are delivered to the doorstep, which means delivery of the product is done at the address desired by the buyer.

Through the development of e-commerce, the Internet has established an electronic global worldwide market that operates 24 hours and 365 days a year. Organizations and individuals are able to market goods and services, while purchasing is supported by secure facilities such as digital signatures (the process that operates on a message to assure message source authenticity and integrity) and encryption (a method of ensuring data secrecy). Developments in software mean that an increased number of facilities are becoming available all the time. Some of the well-known e-commerce sites are www.amazon.com and www.ebay.com.

Mailing Lists (Listserver)

The Internet is home to a large community of individuals who carry out active discussions, organized around topic-oriented forums that are distributed via e-mail. This method of Internet communication is known as mailing list and it enables people with similar interests from all over the world to communicate and share information with each other. The mailing list groups are administered by a software program known as listserver. There are varieties of programs available such as Listserv and Majordomo. A listserver watches for incoming mail on a certain mailbox continuously and forwards any message to a list of other addresses. Such a mailing list can bring people together with a common interest.

21. What is Internet Explorer?

Ans.: Internet Explorer (shortened as IE) is the Microsoft's web browser. On 23 August 1995, Microsoft released their Windows 95 operating system, including a web browser which was named as Internet Explorer. Different versions of IE are available for Windows, Mac, and UNIX. It was developed after Netscape began to turn the computer world upside down with its Navigator browser. After that both companies went head to head on enhancements and features. Although Netscape's browser was a purchased product, Microsoft made IE free, forcing Netscape to do the same. Since Microsoft integrated the browser into Windows 98, IE has become the market leader.

IE makes it easier to get the most from the WWW, whether you are searching for new information or browsing your favourite websites. Its built-in intelligence technology can save your time completing routine web tasks, such as automatically completing web addresses and forms for you and automatically detecting your network and connection status.

22. Describe the address structure of an e-mail. Also, write the steps for its creation.

Ans.: As defined in the previous question, e-mail is the means of exchanging messages electronically, via a communications network, using the computer. It allows the users to communicate with each other in less time and at nominal cost as compared to traditional phone or mail services. Apart from a textual message, it can also consist of other data formats such as pictures, sound, and video.

In order to use e-mail service, one must have access to the Internet and an e-mail account. An e-mail account is a service that allows the user to send and receive e-mails through the Internet. Usually, it is provided as part of ISP's monthly package. One can also obtain free e-mail accounts such as Yahoo and Hotmail on the Web. It provides a unique e-mail address and a mailbox where the user can save all his/her mails.

Generally, there are two parts of an e-mail address: the logon identity and the identity of the e-mail server. These are separated by the symbol @ (pronounced as at the rate). For example, a typical e-mail address would look like the following:

The first part of the address indicates the identifiable name of the user. It is just like a home address (and it is unique) so that the mails could be sent to that address: for example, [email protected]. The ‘@’ symbol in the address is used to separate the user name from the rest of the address. Next comes the host name (itlesl), also called the domain name. This refers to the mail server, the computer where the recipient has an electronic mailbox. It is usually the name of a company or an organization. The end of the domain name consists of a dot (.) followed by three or more letters (such as .com or .net). This part of the domain name indicates the type of organization or the country where the host server is located.

Creating an E-mail Account

To avail the e-mail service of any website, a user must have an e-mail account in that website. A number of websites such as www.yahoo.com, www.gmail.com, www.rediffmail.com, and www.hotmail.com provide free e-mail account. The steps to create an e-mail account on www.yahoo.com website using the Internet Explorer 8 is given as follows:

1. Start Internet Explorer.
2. Type the address ‘www.yahoo.com’ in the address bar and press the Enter key to display Yahoo's home page (Figure 14.2).

   

   Figure 14.2 Home Page of Yahoo

3. Click Mail. A web page appears that allows the new users to create their mail accounts and the existing users to login into their accounts (Figure 14.3).

   

   Figure 14.3 Login Page

4. If you are a new user, click the Sign Up button. The registration form appears as shown in Figure 14.4.

   

   Figure 14.4 Registration Form

5. Fill up all the necessary details in the given text boxes. Some of the entries are compulsory (indicated by the * sign) and some are optional.
6. Read Terms of Service and click on the I Agree button (Figure 14.5).

   

   Figure 14.5 Terms of Services in the Registration Form

7. The confirmation page appears displaying your e-mail ID (Figure 14.6). Now, you can send or receive e-mails using this e-mail ID.

   

   Figure 14.6 Page Showing Registration Completed

23. Explain how e-mail works.

Ans.: To send e-mail, one needs a connection to the Internet and access to a mail server, which forwards the mail. The standard protocol used for sending e-mail is SMTP. It works in conjunction with POP and IMAP servers.

When an e-mail is sent to a person, who has an e-mail address like [email protected], it is broken down into two parts: xyz (the recipient's account name) and hisdomain.com (the recipient's domain name). The SMTP server contacts a DNS (Domain Name Service) server, and asks for the location of hisdomain.com. The DNS server sends the address back to the SMTP server. The SMTP server then sends the e-mail message to the SMTP server where hisdomain.com is located. This SMTP server delivers the e-mail message to xyz’s account on the POP or IMAP server. Finally, when xyz logs on to his/her computer and opens his/her e-mail client, his/her e-mail client requests the POP or IMAP server to send all mails from the account to his/her computer. Note that if you are sending mail to someone whose account resides on the same mail servers, the SMTP server will simply direct the mail to the local POP or IMAP server, where it will be delivered to the appropriate account (Figure 14.7).

Figure 14.7 Working of E-mail System

24. List the advantages and disadvantages of e-mail.

Ans.: E-mail can be sent anywhere in the world to anyone who has an e-mail address. It can take days to send a letter across the country and weeks to go around the world. To save time and money, more and more people are using e-mail. However, the slightest error in the address can deliver the mail to the wrong address. Hence, like there are two faces of a coin, it also comes with its own share of benefits and limitations. They are listed in Table 14.3.

Table 14.3 Advantages and Disadvantages of E-mail

 

S. No.	Advantages	Disadvantages
1.	The delivery of messages is very fast, sometimes almost instantaneous, even though the message is meant for overseas or just to a friend next door.	Although it is delivered instantly, the recipient may or may not read his/her mail on time. That defeats the quickness of e-mailing.
2.	The cost of e-mailing is almost free as it involves negligible amount of telephone and ISP charges.	The user must stay online to read and write more than one mail. In addition, most web mail either display advertisements during use or append them to mails sent It results in increased size of the original mail, which brings a significant decrease in the speed of use.
3.	Multiple copies of the same message can be sent to a group of people at the same time and can be sent as easily to a single person.	Since it passes through a network, it may be intercepted in between.
4.	Pictures, documents, and other files can also be attached to messages.	The slightest error in the address or a failure in one of the links between sender and receiver is enough to prevent a delivery.

 

25. What do you mean by a search engine? What are its components?

Ans.: A search engine is a software that enables you to search information on the Internet. It displays the results of a search based on the criteria entered by the user. That is, the user provides a keyword or a phrase that helps the search engine to start the search. For example, to find information about the various generations of the computer, enter the phrase ‘generations of computer’ and the search engine will display a list of web pages containing the desired information. Some of the popular search engines include Google, Yahoo, and Altavista.

It consists of four components:

1. Spider: It is a program that traverses the Web from link to link, identifying and reading pages. It is also called as wanderer or crawler.
2. Indexing software: It analyzes web pages that are downloaded by spiders.
3. Database: It is the warehouse of the web pages downloaded and processed.
4. Search engine mechanism: It is a software that enables users to query the index and that usually returns results in terms of relevancy ranked order.

26. List the steps involved in the working of a search engine.

Ans.: The working of a search engine involves the following steps:

1. The web spider gathers information about what is available on the Internet. It sends the addresses of the documents to the search engine's indexing software.
2. The indexing software extracts information from the documents and organizes it into a database.
3. When users visit the search engine's web page, they launch a search of its database by typing the keywords that describe the information they are looking for.
4. Search engine looks for the keyword (s) in the index for the database. It creates a new web page displaying the URLs and titles of the document.
5. To go to the actual page, the user just has to click on the link.

27. What is the difference between web browser and web search engine?

Ans.: There are certain differences between a web browser and a web search engine. Some of these differences are listed in Table 14.4.

Table 14.4 Differences Between Web Browser and Web Search Engine

 

S. No.	Web Browser	Web Search Engine
1.	It is software that is used to find information on the Web and display it on the user's computer.	It is an application software that keeps information about where the web pages are stored on the Internet.
2.	It displays the web pages of the current URL.	It gathers information regarding many URLs.
3.	It has no database of its own.	It has its own database containing information about the web pages.
4.	Some examples of web browsers are Internet Explorer, Mozilla, Netscape Navigator, etc.	Some examples of search engines are Google, Yahoo, MSN, etc.

 

28. What are the steps involved in Internet chatting?

Ans.: As discussed earlier, chatting allows users on the Internet to communicate with each other by typing in real time. To avail a chatting service, a chat program or a messenger must be installed on your computer. Some of the most commonly used chat programs are Yahoo Messenger, MSN Messenger, Indiatimes Messenger, and Rediff Bol. To chat on the Internet, follow the steps given below:

1. Start the chat program installed in your computer. For example, start Yahoo Messenger. The Sign In dialog box appears (Figure 14.8).

   

   Figure 14.8 Sign In Dialog Box

2. Enter your Yahoo ID and password and click the Sign In button. A window showing a list of your friends’ names appears (Figure 14.9). Note that the names that are displayed in bold letters are online and hence, you can chat with them.

   

   Figure 14.9 List of Names

3. Double-click the name of a friend with whom you want to chat. The chatting screen appears (Figure 14.10).

   

   Figure 14.10 Chatting Screen

4. Type the message that you want to send and click the Send button or press the Enter key. The message is delivered instantly to your friend and he/she can then reply to your message.

29. What is content streaming?

Ans.: Today, the Internet is vastly being used for audio and video services. Earlier, the user had to wait before playing an audio/video file until the entire file has been downloaded. However, nowadays, the media content can be streamed which implies that the user can listen to or view an audio/video file after its downloading has begun. This provides the users immediate access to file and they can watch or listen to the content only a few seconds after clicking a link. Some examples of online streaming content include YouTube videos and online radio stations.

The audio/video services on the Internet can be streamed either live or on demand. In case of streaming live audio/video, the audio/video files are directly broadcast to the user's computer through the Internet without saving it on the hard disk. Thus, the live streams are available at one time only. Some examples of live audio/video applications include Internet radio and Internet TV. On the other hand, in case of streaming audio/video on demand, the user can download the files stored on a server whenever required using the Internet and these files are often saved on the hard disk of the user's computer. Some examples of stored audio/video include songs, movies, and video clips.

Multiple-choice Questions

1.  Which of the following is not an Internet protocol?

(a) FTP

(b) HTTP

(c) DoD

(d) IP

2.  ISP stands for

(a) Internet Service Promoter

(b) Internet Service Provider

(c) Intranet Service Provider

(d) None of these

3.  Which of the following is not a type of Internet connection?

(a) ISDN

(b) Dial-up

(c) Leased line

(d) ISP

4.  URL is __________.

(a) A computer software program

(b) A type of web server

(c) The address of a document or ‘page’ on the Web

(d) An acronym for Unlimited Resources for Learning

5.  What does the URL ‘http://www.uni.edu’ tell you about the source?

(a) It is associated with an educational institution.

(b) It is associated with a military establishment.

(c) It is associated with a commercial organization.

(d) None of these.

6.  Which of the following protocols is used to transfer news messages over the Internet?

(a) TCP/IP

(b) NNTP

(c) SMTP

(d) HTTP

7.  Which of the following is not a component of the search engines?

(a) Crawler

(b) Indexing software

(c) URL

(d) All of these

8.  Which of the following symbols separates the two parts of an e-mail address?

(a) _

(b) &

(c) @

(d) None of these

9.  Usually, the e-mail address is in __________.

(a) Lower case

(b) Proper case

(c) Upper case

(d) All of these

Answers

1. (c)

2. (b)

3. (d)

4. (c)

5. (a)

6. (b)

7. (c)

8. (c)

9. (a)