Understanding The Internet

Understanding
the Internet

What is the Internet?

In such an information era, you have heard about “the Internet”, and very probably, may have experience of using the Internet. However, can you answer the question: “What is the Internet?” confidently without any hesitation. After reading through this section, you can give a better answer to this question.

Some think that the Internet is a computer network allowing people to share information. Others say that the Internet is a worldwide network allowing people in different locations of the world to communicate. Some others state the Internet is a worldwide resource center. There may be many more suggestions. What do you think?

In fact, the Internet is much more than these. The Internet is a living entity and is ever growing, It is not just a vast, worldwide computer network, it is also consisting of the information storing in it and the people participating in it.

The Internet is growing because more and more computers are connected to the Internet day by day, and the number of people participating in it is increasing rapidly. The information stored in it is much richer in every second as the people participating in the Internet are providing more information and more people are added in to provide their information. The Internet is so large and complex that no one can control it, or just be able to understand all of it.

When talking about the origin of the Internet, we have to date back to thirty years ago. At that time, the United States Department of Advanced Research Projects Agency (ARPA) sponsored a project named the ARPANET. The goal is to build a network that could maintain itself under adverse condition so that it can carry military and government information during wars. After many meeting and the formation of the ARPANET working group, the ARPANET project was started in 1968. The goal of the project was soon changed into a more general one in developing techniques to build a large-scale network.

In the first few years of their work, the ARPANET working group aimed at developing a single large network to connect computers over long distances to span the globe. After several years working, they found out that there was no single network that can serve the needs of everyone. They determined that it is far better to develop technology for connecting different types of networks together to form a single large system. This is the fundamental of the “inter-networking” concept.

The project was continued for many years and then was phased out gradually. However, the influences of this project continue up to now and the near future. Through this project, the technology to connect computers together reliably and economically had been developed. Under this project, a global backbone of computer networks has been formed which we now call it the Internet. The name “Internet” is derived from the word “inter-networking” for it is a collection of tens of thousands of networks.

Now, you can through the Internet to communicate, to get information, to express your opinions, to advertise your products, and to do many other things you may think of. The beauty of the Internet is not on the global network itself but on the information you need, at any time, through the Internet because information on any disciplines is already there. The resources are there because of the volunteered participants who placed their worthwhile information in the Internet. You can also chat with other participants or join any discussion group in the Internet.

Once participated in the Internet, you can realize that it is a world of information and people, but not just a network.

Some Technical Aspects of the Internet

To be a computer Internet user, it is a must to learn some of its technical issues. This is the purpose of our writing this section to let you have a glance on the technical details of the Internet. As the ASL Computer Applications syllabus only requires you to have an understanding on the basic technical issues, we will just cover the basic concepts and terms, and keep the discussion on technical issues simple.

Computer Network

A computer network is a set of two or more computers connected together. The major reasons of connecting computers together to form a network is to allow users to communicate and to facilitate the sharing of resources. Any two users of the same network can communicate and share data or any other resources. Although both computer networks and mainframes can serve the above two purposes, computer networks superseded mainframes because of the much higher reliability and performance over price ratio. Furthermore, it is much easier o expand a computer network than a mainframe.

A computer network can be classified as a Local Area Network (LAN) or a Wide Area Network (WAN). A LAN refers to the connection of computers within a local area such as a room, a building, a school, a department, an organization, etc. The maximum length of an individual LAN is usually limited to about 1or 2 km.

There are three most common standard topologies of connecting computers to form a LAN. They are Star network, Bus network, and Ring network. In a star network, computers are connected to a central computer which provides the major resources. In a bus network, there is a fast cable forming the backbone of the network and all computers are connected to this cable. In a ring network, computers are connected to form a ring.

A WAN is a network that covers a large geographical area such as a city, a state a country, or even multiple countries. WANs are generally formed by connecting LANs together. One way of connecting LANs is to make use of devices called bridge and gateway. A bridge is responsible for connecting LANs of the same type while a gateway is responsible for connecting LANs of different types.

Another way of connecting LANs to form a WAN is to use a very high- speed link as a backbone with all LANs connected to this backbone. This backbone may usually provide a link to the outside world as well.

A special-purpose computer, called a router, can connect WANs together to form even large WANs. As discussed in the previous section, the Internet is in fact formed by connecting the WANs and the LANs in the world. Hence, as an Internet user, you can communicate with any other Internet users throughout the world.

Clients and Servers

As you’ve seen, the Internet is an extremely large wide area network. Then, how can the network provide facilities to the users and how can the users get access to the facilities of the network? The answer is: these are done through using two types of programs, clients and servers, which are populated in the Internet. The Internet is constructed in such a way that users can use client programs to talk to server programs that provide facilities.

As an example, the Internet supports a large system called the World Wide Web (WWW), also just called the Web. There is a great number of web servers scattered all around the Internet. These web servers can respond to requests for information. The users use web clients to get information from these web servers.

The information provided by web servers are organized into ‘pages’ and each page of information is called a web page. A web page can contain text, pictures, sound, or even animation. A web client helps you to contact the appropriate web server to send you the page containing the requesting information. The web client then displays the page on your screen. If necessary, the web client will call upon auxiliary programs to play a sound or animation.

The power of web pages comes from the links to other web pages. When you use a web client to view a web page, you can tell it to follow a particular link to jump to another web page. The new web page reference may be provided by another web server. It may even be located in a different country. Your web client will help you to contact the web server that contains the new page. The web server will send it to your web client, which will then display it on your screen. All these are done by your web client and are transparent to you.

We call the web client program a browser. Currently, two browser have dominated the world market. One is the “Internet Explorer” developed by the Microsoft Corporation. The other one is the “Netscape Communicator” developed by the Netscape Corporation.

As other example, the Internet provides a facility to the users to send, receive, and read electronic mail (or email). To do so, mail server. The mail server maintains an electronic mailbox that helps receiving and keeping electronic mails. It also helps delivering outgoing electronic mails. It also helps delivering outgoing electronic mails.

To read your electronic mails, you use your mail client to contact the mail server that maintains a mailbox for you. The mail server will send your mail client the electronic mails in your mailbox. The mail client will then display them on your screen. The mail client will hen display them on your screen. The mail client also helps you ti write replies, keeps an address book for you, and maintains a mailing list.

As you see, to use the electronic mail facility of the Internet, you don’t need to know anything about the mail server. You just need to learn to use the mail client. The mail client will help you to contact the mail server. The mail server will then do its job for you.

To conclude, you see that resource providers use server programs to provide facilities to users, while users like you use client programs to access the facilities. As a user, you only need to learn to use the corresponding client program to access a particular kind of facilities.