Both computers and computer networks are indispensable to us now. All workplaces contain computers, and they are invariably interconnected. If they are connected via a LAN, they can communicate with other computers. In most residential flats, computers are connected to the Internet through dial-up or broadband connections for e-mail, Web browsing, and the like.
Apart from at home and in the office, computer networks are present in all mass transport systems for the smooth operation of ticketing systems, carriage signalling, and safety protection and performance analysis. Doing business requires computer networks as well. When we eat or shop, computer networks come in to connect the ordering, inventory and payment systems.
The administration of a country or a city also needs computers and computer networks. For example, computer networks are required to allow access to information, including citizen and business registration information, at different government offices. Computer networks are required to support checking our identity at border control points, and for operating traffic lights
Computer networks have the following three goals:
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Overcoming geographic separation
Computer networks overcome geographical separation in a city and across countries. Computers that need to communicate with other computers are often located in different parts of the world, and they need computer networks to pass information across long distances to overcome that geographical separation.
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Allowing information sharing
Computer networks allow information sharing by allowing connected people or computers to access information on databases distributed in different locations. There are databases hosted on many computers. People or computers may need to access the data in these databases. Without a computer network, it would take a long time to select and transport the required data from the database to the requiring users. With computer networks, we can conveniently access the databases to retrieve data.
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Supporting distributed processing
Computer networks support processing distributed in different locations. These different locations can be physically close together inside a single computer room, or they can be separated by a long distance across mountains and oceans. Physical transportation of the intermediately processed data is impractical. Hence, a computer network becomes indispensable in distributed processing. It allows timely passing of semi-processed data between computers located in distributed locations.
Computer networks have indeed become indispensable now. Hence we need to study computer networks in terms of their basic components, their architecture and how they support the Internet applications in a typical enterprise. All of these affect our daily life.
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