A network is defined as a group of two or more computers linked together for the purpose of communicating
and sharing information and other resources, such as printers and applications. Most networks are
constructed around a cable connection that links the computers, however, modern wireless networks that use
radio wave or infrared connections are also becoming quite prevalent. These connections permit the
computers to communicate via the wires in the cable, radio wave or infrared signal. For a network to
function it must provide connections, communications, and services.
• Connections are defined by the hardware or physical components that are required to connect a
computer to the network. This includes the network medium, which refers to the hardware that
physically connects one computer to another, i.e., the network cable or a wireless connection; and the
network interface, which refers to the hardware that attaches a computer to the network medium and is
usually a network interface card (NIC).
• Communications refers to the network protocols that are used to establish the rules governing network
communication between the networked computers. Network protocols allow computers running different
operating systems and software to communicate with each.
• Services define the resources, such as files or printers, that a computer shares with the rest of the
networked computers.