3.5 - Networks, PANs, LANs and WANs

Networks and their benefits and costs

A computer network connects two or more computing devices so that they can communicate and share data or resources.

Imagine a school with thirty computers. Without a network, a teacher might copy a worksheet onto each computer separately. With a network, the teacher can put one copy in a shared folder and give the class access. The computers can also send jobs to a shared printer rather than each needing a printer. These are different benefits: sharing data reduces repeated copying, while sharing hardware can reduce purchasing costs.

Users can communicate through messages and collaborate on shared work. Central management can let an administrator update software, control user access and back up shared data. If a pupil moves to another computer, an authorised account may still reach the pupil's network files.

Connection also creates costs and risks. Cables, network equipment and administration cost money. A fault in a shared file server can prevent many users reaching their work. An insecure shared folder can expose data to unauthorised users; malicious software may spread between connected devices. Sharing a resource can create a bottleneck, such as a queue at the only printer. A network therefore needs maintenance, security and enough capacity for its users.

Worked decision. A small design studio buys one high-quality network printer. Sharing it saves the cost of buying five printers, and everyone can use the same quality of output. However, if it fails, all five staff lose that printing service. This is a consequence of relying on a shared resource, rather than evidence that networks always fail.