- The main goal of networking is "Resource sharing", and it is to make all programs, data and equipment available to anyone on the network with out the regard to the physical location of the resource and the user.
- A second goal is to provide high reliablity by having alternative sources of supply. For example, all files could be replicatied on two or three machines, so if one of them is unavailable, the other copies could be available.
- Another goal is saving money. Small computers have a much better price/performance ratio than larger ones. Mainframes are roughly a factor of ten times faster than the fastest single chip microprocessors, but they cost thousand times more. This imbalance has caused many system designers to build systems consisting of powerful personal computers, one per user, with data kept on one or more shared file server machines. This goal leads to networks with many computers located in the same building. Such a network is called a LAN(local area network).
- Another closely related goal is to increase the systems perfomance as the work load increases by just adding more processors. With central mainframes, when the system is full, it must be replaced by a larger one, usually at great expense and with even greater disruption to the users.
- Computer networks provide a powerful communication medium. A file that was updated/modified on a network, can be seen by the other users on the network immediately.
- Access to remote programs.
- Access to remote databases.
- Value-added communication facilities.
Calling up a distant computer via a network is cheaper than calling it directly. The lower rate is possible because in a normal telephone call ties up an expensive, dedicated circuit for the duration of the call, whereas access via a network ties up long-distance lines only while data are actually being transmitted.