The Internet is a public network. But sometime we may not need to connect to the whole world. For those situations, Intranet or Extranet best that suites our needs.

An intranet is a private network that is contained within an enterprise. It may consist of many interlinked local area networks and also use leased lines in the wide area network. The main purpose of an intranet is to share company information and computing resources among employees. An intranet can also be used to facilitate working in groups and for teleconferences. When a part of an intranet is made accessible to customers, partners, suppliers, or others outside the company, that part becomes part of an extranet.



In this chapter, you will learn to:

  •  What is Internet.
  •  Difference between internet and intranet.
  • Introduction to World Wide Web
  •  What is Social Media.


Internet is a worldwide collection of computer networks. Internet is a cooperative effort of many people and organizations. The computers on the Internet can communicate because they are physically linked and because they share a common language called TCP/IP.

Protocol: When computers communicate with each other, there needs to be a common set of rules and instructions that each computer follows. A specific set of communication rules is called a protocol. Because of the many ways computers can communicate with each other, there are many different protocols. Some examples of these different protocols include PPP, TCP/IP, SLIP, HTTP, and FTP.

Transmission Control Protocol (TCP):Transmission Control Protocol (TCP) is one of the most used protocols in digital network communications and is part of the Internet protocol (IP) suite, commonly known as the TCP/IP suite. Primarily, TCP ensures end-to-end delivery of data between distinct nodes. TCP works in collaboration with Internet Protocol, which defines the logical location of the remote node, whereas TCP transports and ensures that the data is delivered to the correct destination.

Before transmitting data, TCP creates a connection between the source and destination node and keeps it alive until the communication is active. TCP breaks large data into smaller packets and also ensures that the data integrity is intact once it is reassembled at the destination node.

Internet protocol (IP): Internet Protocol (IP) is the principal set (or communications protocol) of digital message formats and rules for exchanging messages between computers across a single network or a series of interconnected networks, using the Internet Protocol Suite (often referred to as TCP/IP). The main purpose and task of IP is the delivery of datagrams from the source host (source computer) to the destination host (receiving computer) based on their addresses. To achieve this, IP includes methods and structures for putting tags (address information, which is part of metadata) within datagrams. The process of putting these tags on datagrams is called encapsulation.


Birth of Internet?

The INTERNET was born in 1969, when a paranoid American military had nightmares about the primary communication centres being bombed out by Russians. To prevent such occurrence, the ARPA(Advanced Research Projects Agency) set up four communication hosts, linking them in such a fashion which would ensure that even if one got bombed out. Communication would route around the affected area and stay alive. This network called ARPA net quickly grew. This primary service on ARPA net was electronic mail. It was the first time that emails actually came into use. In very short time, students began linking their own campus networks into ARPA net, using a well-defined protocol TCP-IP.

This joining of networks was also called inter-networking, and soon the entire setup was called INTERENT. In 1973, ARPA net allowed international bodies to the net, and after that there was no looking back.

Who owns the Internet?

No one person, service, corporation, university or Government owns the Internet. Each connected individual or group owns its own network. Each person who desires telephone service contacts the local area service provider. The service provider provides the hook-up from the residence or business to service network. The Internet mostly connects network of computers. The Internet is also called as the Global Internet because networks from most of the countries with some sort of telephone service infrastructure is connected to it. Practically this means people can use their computers on their local networks to messages or exchange files with people using in another company or in another state, geographic region, or another country.

How does the Internet actually work?

The Internet is like a vast transportation system for data. The system includes and connects local, regional, nation and international networks. This Internet expands daily as more networks and computers connect to it.

Let’s say that a person in Hyderabad wants to get information from another person in Tokyo, Japan. Now if these two people are in the same company, using some corporate wide email system, the first person just enters in the name of the second person as it is known to the corporate e-mail system- usually, a user name. This server as an address on the electronic message, and the send command has the email system deliver the message to the second person. In the Internet community, people believe in sharing their ideas and opinions with others. This is so mainly because it is an open forum that has government and no restrictions at all. This policy of openness has led Internet-citizens to put up an enormous variety of hypertext document on the web. This has led to information of every kind being available to anybody who wants it.


The Internet is a public network. But sometime we may not need to connect to the whole world. For those situations, Intranet or Extranet best that suites our needs.

An intranet is a private network that is contained within an enterprise. It may consist of many interlinked local area networks and also use leased lines in the wide area network. The main purpose of an intranet is to share company information and computing resources among employees. An intranet can also be used to facilitate working in groups and for teleconferences. When a part of an intranet is made accessible to customers, partners, suppliers, or others outside the company, that part becomes part of an extranet.



The Internet is a world-wide/global system of interconnected computer networks.

  • Internet uses the standard Internet Protocol (TCP/IP)
  • Every computer in the internet is identified by a unique IP address.
  • IP Address is a unique set of numbers (such as which identifies a computer location.
  • A special computer DNS (Domain Name Server) is used to give a name to the IP Address so that user can locate a computer by a name.
  • For example, a DNS server will resolve a name to a particular IP address to uniquely identify the computer on which this website is hosted. 6) Internet is accessible to every user all over the world.



  • An intranet is a 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.
  • Each computer in Intranet is also identified by an IP Address, which is unique among the computers in that Intranet.


Similarities in Internet & Intranet
  • Intranet uses the internet protocols such as TCP/IP and FTP.
  • Intranet sites are accessible via web browser in similar way as websites in internet. But only members of Intranet network can access intranet hosted sites.
  • In Intranet, own instant messengers can be used as similar to yahoo messenger/gtalk over the internet.
Differences in Internet & Intranet
  • Internet is general to PCs all over the world where Intranet is specific to few PCs.
  • Internet is wider access and provides a better access to websites to large population whereas Intranet is restricted.
  • Internet is not as safe as Intranet as Intranet can be safely privatized as per the need.


Introduction to World Wide Web 

The World Wide Web is an information retrieval system based on hypertext. In hypertext selected words or areas on the screen are expandable, leading to more details about the subject. A hypertext allows you to view information without using complex commands and without even using a source of information. When a hyperlink is attached to text it is called hypertext.

A browser is a client application used to access the information on www. The browser displays web pages and makes the connection necessary to follow hypertext links.www is a global hypertext system that uses the Internet as its transmission medium. The www enables you to access information on the Internet without the use of complicated commands. By linking resources throughout the Internet, the web brings a world of information to your doorstep. The www could be very simply defined as a universal database of knowledge. Information that is easily accessible to people around the world and links easily to other pieces of information. This allows any user to quickly find the things most important to themselves. It is an Internet resource where one can get information about different topics such as the latest trends in programming language.

Origins of the World Wide Web

Like many Internet technologies, the WWW has its origins in the research community. The

The web is based on HTTP, the Hypertext Transfer Protocol, Which was developed at CERN, the European Laboratory for Particle Physics in Switzerland. Web technology developed originally to help researcher’s access information and share their work via the Internet. Prior to the development of the web, researchers at CERN had to use a variety of operating systems and programs to access information. The web provided them with a single mechanism for information retrieval, regardless of the type of computer and the type of resource. After CERN established specifications for the web, software for web services and clients developed quickly on the Internet. Today there are thousands of web servers throughout the world. Web browsers, who are available for just about every type of computer made enable millions of people to use the www.The two main uses of the World Wide Web are to retrieve resources and to publish information on the Internet. You can access almost any Internet resource using the www. You can publish your own hypertext documents on the World Wide Web. Web documents are written in HTML. HTML editors and file converters are available to simplify the task of creating documents that contain embedded links to other information.



WWW Gateways to other services

Through the www you have access, not just to web hypertext documents or pages, but also to other Internet resources. The web connects directly to some of these resources. A gate way is a link between two systems that perform a similar function but work differently. The gateway translates addresses and protocols between two systems so that they can work together.

Introduction to URL’s

Every web page or Internet resource accessible through the www has a unique name, this is URL (Uniform Resource Locator). The URL identifies and locates a resource so that a web browser can access it directly. A URL is type of Internet address.


The language that Web clients and servers use to communicate with each other is called the Hyper Text Transfer Protocol (http). All the web clients and servers must be able to speak http in order to send and receive hypermedia documents. For this reason web servers are often called http servers.

Surfing in the Internet

The Internet is a big place, and getting information from it can seem a little daunting. It’s really not very hard, though. All you have to do is ask one of the many search engines to go and look for you. Well, it’s a little harder than that. You have to know HOW to ask the search engines.

Now, What is ‘Search Engine’?

A search engine is a software program or script available through the Internet that searches documents and files for keywords and returns the results of any files containing those keywords. Today, there are thousands of different search engines available on the Internet, each with their own abilities and features. Or simply we can say,

“AsearchengineisaWebsiteusedtosearchforinformationontheWorldWideWeb.” The first search engine ever developed is considered Archie, which was used to search for FTP (File Transfer Protocol) files and the first text-based search engine is considered Veronica. Today, the most popular and well known search engine is Google.

Googlefirstcollectswebsitesusingacomputerprogram(calledawanderer,crawler,robot,worm, orspider).ThenGooglecreatesanindexofthesesitessotheyaresearchable.Therearemanysearcheng inesthatareavailable–‐weuseGoogleforpurposesofinstructionbecausemostpeopleuseit.



A hundred years ago a message took 7 days to travel from coast to coast and even longer to cross the ocean. With the advent of airmail, that time was cut to 3 or 4 days. Today overnight mail delivery is available in certain areas, for a hefty surcharge. But faxing and electronic mail provide faster and inexpensive delivery of messages.

The way electronic mail works on the Internet is similar to the way the postal system works. The address is the most important part of both standard letters and e-mail messages. If the address is incorrect the intended recipient will never see the message. A major difference between electronic and postal mail is that e-mail is significantly faster. Depending on how often the mail systems handling the message check for new mail and how much Internet traffic there is, your e-mail message can arrive in as short a time as thirty seconds as it might take as long as a day. But it certainly takes a less time than postal mail.

e-mail is a service for exchange for exchanging messages among computers. Many

commercial online services are corporations also provide e-mail exchanges via the Internet. There are many software platforms available to send and receive. Popular email platforms include Gmail, Hotmail, Yahoo! Mail, Outlook, and many others.


 Social media is an internet-based form of communication. Social media platforms allow users to have conversations, share information and create web content. There are many forms of social media, including blogs, micro-blogs, wikis, social networking sites, photo-sharing sites, instant messaging, video-sharing sites, podcasts, widgets, virtual worlds, and more. The kinds of Internet services commonly associated with social media include the following:

Blogs: A blog  is a discussion or informational site published on the World Wide Web and consisting of discrete entries (“posts”) typically displayed in reverse chronological order (the most recent post appears first).

Wikis: A wiki is “a collective website where any participant is allowed to modify any page or create a new page using her Web browser. One well-known example is Wikipedia, a free online encyclopedia that makes use of wiki technology

Social bookmarking: A social bookmarking service is a centralized online service which enables users to add, annotate, edit, and share bookmarks of web documents. Social bookmarking sites allow users to organize and share links to websites. Examples include reddit, Stumble Upon and Digg.

Social network sites: These have been defined as “web-based services that allow individuals to construct a public or semi-public profile within a bounded system, articulate a list of other users with whom they share a connection, and view and traverse their list of connections and those made by others within the system.” Among the most popular in Facebook and LinkedIn.

Status-update services. Also known as microblogging services, status-update services such as Twitter allow people to share short updates about people or events and to see updates created by others.

Virtual world content. These sites offer game-like virtual environments in which users interact. One example is the imaginary world constructed in Second Life in which users create avatars (a virtual representation of the user) that interact with others.

Media-sharing sites. These sites allow users to post videos or photographs. Popular examples include YouTube, Pinterest and Instagram.

Billions of people around the world use social media to share information and make connections. On a personal level, social media allows you to communicate with friends and family, learn new things, develop your interests, and be entertained. On a professional level, you can use social media to broaden your knowledge in a particular field and build your professional network by connecting with other professionals in your industry. At the company level, social media allows you to have a conversation with your audience, gain customer feedback, and elevate your brand.

While there are many types of social media sites available for use, there are few sites which is most popular on the internet: Facebook, Foursquare, Instagram, LinkedIn, Pinterest, Tumblr, Twitter, and YouTube. Below is a summary of each site.

Facebook is a social networking site that allows people from around the world to network with friends, companies and organizations. Facebook was founded on February 4, 2004, by Mark Zuckerberg with his college roommates and fellow Harvard University students.

Foursquare is a location-based social networking site available to users with GPS-enabled mobile devices. Such as smartphones. Users “check in” at venues using a mobile website, text messaging or a device-specific application by selecting from a list of venues the application locates nearby.

 Instagram is a social networking site that allows users to share pictures and short videos using their mobile device.

LinkedIn: is a business-related social networking site used mainly for professional networking. The basic functionality of LinkedIn allows users (workers and employers) to create profiles and “connections” to each other in an online social network which may represent realworld professional relationships.

Pinterest: is a social networking site that allows users to organize and share content using virtual pin boards. People use Pinterest to collect ideas for projects and interests. Users create and share collections (called “boards”) of visual bookmarks (called “Pins”) that they use to do things like plan trips, develop projects, organize events or save articles and recipes.

Tumblr is a blogging site that allows users to post text, images, videos, links, quotes and audio. It is a microblogging platform and social networking website founded by David Karp and owned by Yahoo! Inc. The service allows users to post multimedia and other content to a shortform blog. Users can follow other users’ blogs, as well as make their blogs private.

Twitter is a micro-blogging site that allows people to post updates in 140 characters or less.

YouTube is the world’s largest video sharing site. Departments with a videographer or high volume of videos should consider creating a YouTube channel to publish their videos.