First: computer networks and their devices

Definitions

• An information and communications network is a web-like network that uses communication lines to carry information.
• A computer network is a communication system that links information and communication devices — computers and smart phones — so that they exchange data with each other.

Types

• LAN (Local Area Network): links devices inside a limited area such as a school or a home.
• Wired LAN: data is exchanged through direct connection by cables.
• Wireless LAN: data is exchanged by radio waves instead of cables.
• WAN (Wide Area Network): links distant areas and covers a wider range than a LAN.
• The Internet: a world network that connects LANs and WANs to one another.

Connection devices

• ISP (Internet Service Provider): a company that makes Internet access available; a contract with one is needed to get the service.
• Router: a device that passes data on and re-directs it between different networks.
• Hub: a central connection point to which several cables are attached; a switch does the same job but forwards each frame only to its destination port.
• Modem: converts digital data to a signal the line can carry and back again; the NIC (network interface card) is the card that puts a device on the network, and an access point serves the wireless side of it.