Ch 1Networking and Open Standards — Class 12 Information Technology, concept-first.

A single computer working on its own is useful, but a computer that can talk to other computers is far more powerful.

A computer network is a group of two or more computers and other devices connected together — by cables or wirelessly — so that they can communicate with one another and share resources.

Networks are classified mainly by the area they cover — from a network around a single person to a network spanning the globe. The four common types are the PAN, LAN, MAN, and WAN.

To build a network, computers must be connected and the signals passing between them must be directed and, where needed, strengthened. This is the job of network devices.

A network topology is the physical or logical arrangement in which the computers and devices of a network are connected together — the "shape" or layout of the network.

Communication media (also called transmission media) are the paths along which data signals travel from one device to another in a network.

The Internet is the worldwide network of networks — the largest computer network in the world, joining hundreds of millions of computers and devices across every country so that they can share informa…

For millions of different computers to communicate reliably across the Internet, they must all follow the same agreed rules.

The Internet has changed the way we communicate, learn, work, and do business. Its main applications include the following.

Wireless communication carries information through the air as waves, with no connecting cable, allowing people to communicate while on the move. Mobile telephones are the most familiar example.

Connecting a computer to a network, and especially to the Internet, brings great benefits but also exposes it to threats — harmful programs and attacks that can damage data, steal information, or misu…

As more of our lives and business move online, criminals also use computers and the Internet to commit offences.

For different computers, programs, and devices — often made by different companies — to work together on a network, they must agree on common ways of doing things.