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Concepts of Networking. |
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What is a Computer Network?
The merging of computers and communications has had a profound influence on the way computer systems are organized. The concept of the "computer center" as a room with a large computer to which users bring their work for processing is now obsolete. The old model of a single computer serving all of the organization's computational needs has been replaced by one in which a large number of separate but interconnected computers do the job. These systems are called computers networks.
Why a Computer Network? A question may arise that why we need a computer network? The answer is simple and can be answered in the following few points:1.) To distribute pieces of computation among computers. 2.) To have coordination between processes running on different nodes. 3.) To access remote I/O devices. 4.) To have remote data/file access. 5.) For personal communication (like e-mail, chat, audio/video conferencing). 6.) The World Wide Web Uses of Computer Networks There can be large number of uses and utilities of computer networks and some of them can be given as:1.) Network for Companies Many organizations have a substantial number of computers in operation, often located far apart. For example, a company with many factories may have a computer at each location to keep track of inventories, monitor productivity, and do the local 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. Put in slightly more general form, the issue here is resource sharing, and the goal is to make all programs, equipment, and especially data available to anyone on the network without regard to the physical location of the resource and the user. A second goal is to provide high reliability by having alternative sources of supply. For example, all files could be replicated on two or three machines, so if one of them is unavailable, the other copies could be used. Another goal is saving money. Small computers have a much better price/performance ratio than large ones. Another networking goal is scalability, the ability to increase system performance gradually as the workload grows just by adding more processors. Yet another goal of setting up a computer network has little to do with technology at all. A computer network can provide a powerful communication medium among widely separated employees. 1.) Network for People The motivations given above for building computer networks are all essentially economic and technological in nature. If sufficiently large and powerful mainframes were available at acceptable prices, most companies would simply choose to keep all their data on them and give employees terminals connected to them. In the 1970s and early 1980s, most companies operated this way. Computer networks only became popular when networks of personal computers offered a huge price/performance advantage over mainframes. Starting in the 1990s, computer networks began to start delivering services to private individuals at home. These services and the motivation for using them are quite different than the "corporate efficiency" model. Below are the three of the more exciting ones that are starting to happen: i. Access to remote information. ii. Person-to-person communication. iii. Interactive entertainment. details |
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