Introduction to computer network

What is Network? Benefits of Networking

A network consists of 2 or more computers connected together, and they can communicate and share resources (e.g. information) 

Why Networking?

Sharing information — i.e. data communication

Uses of Computer Networks 

Computer networks are collections of autonomous computers, e.g., the Internet

They have many uses:-

• Business Applications »

• Home Applications »

• Mobile Users »

We will start with traditional uses at companies and for individuals and then move on to recent developments regarding mobile users and home networking. 

1. Business Applications 

Many companies have a substantial number of computers. For example, a company may have separate computers to monitor production, keep track of inventories, and do the payroll. Initially, each of these computers may have worked in isolation from the others, but at some point, management may have decided to connect them to be able to extract and correlate information about the entire company. 

Every large and medium-sized company and many small companies are vitally dependent on computerised information. Most companies have customer records, inventories, accounts receivable, financial statements, tax information, and much more online. If all of its computers went down, a bank could not last more than five minutes. 

For smaller companies, all the computers are likely to be in a single office or perhaps a single building, but for larger ones, the computers and employees may be scattered over dozens of offices and plants in many countries. 

2. Home Applications

Homes contain many networked devices, e.g., computers, TVs, connected to the Internet by cable, DSL, wireless, etc.Home users communicate e g social networks consume Home users communicate, e.g., social networks, consume content (video etc..), and transact(Auction…),Some application use the peer-to-peer model in which there are no fixed clients and servers:

Probably the biggest reason now is for Internet access. Some of the more popular uses of the Internet for home users are as follows: 

1. Access to remote information. 

2. Person-to-person communication. 

3. Interactive entertainment. 

4. Electronic commerce. 

Access to remote information comes in many forms. It can be surfing the World Wide Web for information or just for fun. Information available includes the arts, business, cooking, government, health, history, hobbies, recreation, science, sports, travel, and many others. Fun comes in too many ways to mention, plus some ways that are better left unmentioned. 

Person-to-person communication really hit the big time around 2000 with a service called Napster, which at its peak had over 50 million music fans swapping music, in what was probably the biggest copyright infringement in all of recorded history. The idea was fairly simple. Members registered the music they had on their hard disks in a central database maintained on the Napster server. If a member wanted a song, he checked the database to see who had it and went directly there to get it. By not actually keeping any music on its machines, Napster argued that it was not infringing anyone’s copyright. The courts did not agree and shut it down. 

Entertainment, which is a huge and growing industry. The killer application here (the one that may drive all the rest) is video on demand. A decade or so hence, it may be possible to select any movie or television program ever made, in any country, and have it displayed on your screen instantly. New films may become interactive, where the user is occasionally prompted for the story direction (should Macbeth murder Duncan or just bide his time?) with alternative scenarios provided for all cases. Live television may also become interactive, with the audience participating in quiz shows, choosing among contestants, and so on. 

Electronic commerce in the broadest sense of the term. Home shopping is already popular and enables users to inspect the on-line catalogues of thousands of companies. Some of these catalogues will soon provide the ability to get an instant video on any product by just clicking on the product’s name. After the customer buys a product electronically but cannot figure out how to use it, on-line technical support may be consulted. 

3. Mobile Users 

Mobile computers, such as notebook computers and personal digital assistants (PDAs), are one of the fastest-growing segments of the computer industry. Many owners of these computers have desktop machines back at the office and want to be connected to their home base even when away from home or en route. Since having a wired connection is impossible in cars and aeroplanes, there is a lot of interest in wireless networks. In this section we will briefly look at some of the uses of wireless networks. 

4. Social Issues 

The widespread introduction of networking has introduced new social, ethical, and political problems. A popular feature of many networks are newsgroups or bulletin boards whereby people can exchange messages with like-minded individuals. As long as the subjects are restricted to technical topics or hobbies like gardening, not too many problems will arise. 

Another fun area is employee rights versus employer rights. Many people read and write emails at work. Many employers have claimed the right to read and possibly censor employee messages, including messages sent from a home computer after work. Not all employees agree with this.