Network architecture is a description of how a computer is set-up (configured) and what strategies are used in the design. The interconnection of PCs over a network is becoming more important, especially as more hardware is accessed remotely and PCs intercommunicate with one another. 3.1 Terms used to describe computer networks • Node – any device connected to a network such as a computer, printer or data storage device. • Client – a node that requests and uses resources available from other nodes. Typically a microcomputer. • Server – a node that shares resources with other nodes. May be called a file server, printer server, communication server, web server or database server. • Network Operating System (NOS) – the operating system of the network that controls and coordinates the activities between computers on a network, such as electronic communication and sharing of information and resources. • Distributed processing – computing power is located and shared at different locations. Common in decentralised organisations (each office has its own computer system but is networked to the main computer). • Host computer – a large centralised computer, usually a minicomputer or mainframe. DATA COMMUNICATION & COMPUTER NETWORKS
MANAGEMENT INFORMATION SYSTEMS 230 S T U D Y T E X T 3.2 Types of computer networks Different communication channels allow different types of networks to be formed. Telephone lines may connect communications equipment within the same building. Coaxial cable or fibre- optic cable can be installed on building walls to form communication networks. You can also create your own network in your home or apartment. Communication networks also differ in geographical size. Three important networks according to geographical size are LANs, MANs and WANs. Local Area Network (LAN) A LAN is a computer network in which computers and peripheral devices are in close physical proximity. It is a collection of computers within a single office or building that connect to a common electronic connection – commonly known as a network backbone. This type of network typically uses microcomputers in a busy organisation linked with telephone, coaxial or fibre-optic cable. A LAN allows all users to share hardware, software and data on the network. Minicomputers, mainframes or optical disk storage devices can be added to the network. A network bridge device may be used to link a LAN to other networks with the same configuration. A network gateway device may be used to link a LAN to other networks, even if their configurations are different. Metropolitan Area Network (MAN) A MAN is a computer network that may be citywide. This type of network may be used as a link between office buildings in a city. The use of cellular phone systems expands the flexibility of a MAN network by linking car phones and portable phones to the network.
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