Theory‎ > ‎


LAN: Local Area Network, Computers and peripherals in close proximity typically one building or site that has been connected together.


WAN: Wide Area Network, A set of links that connects geographically remote computers and local area networks.


MAN: Metropolitan Area Network, a city wide network linked by cables or microwaves. e.g. a city Wi-Fi.


Internet the international network of interconnected computers, sometimes called a network of networks. It is the physical infrastructure i.e. cables and servers.


World Wide Web the collection of web pages and multimedia resources available on the internet.


Intranet is a service that uses internet technologies (protocols) to distribute information securely and privately within a single organisation over its internal network.


Extranet is an extension of a company’s private intranet where individuals can have authorised access to it by logging on securely over the internet.


Hub: small, simple and cheap device to connect network devices communication by broadcasting data and therefore less secure. Not used much nowadays.


Switch: More complex and expensive than hub and can direct packets. Connects at the data link layer.


Router: Most expensive and complex of the three, as it is programmable. It can set filters like keyword, blacklist and whitelist. Connects networks at the network protocol layer.


Protocol a description of a set of procedures / or known rules to be followed when communicating.


IP – Internet Protocol, a unique address that identifies a computer on a network. Allows packets to be directed from source to destination.


TCP – Transmission Control Protocol ensures that data is sent and received accurately (assemble or resend).