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Critism On So Long A Letter

LAN
Local Area Network or LAN, in computer science, a group of computers and other devices dispersed over a relatively limited area and connected by a communications link that enables any device to interact with any other on the network. LANs commonly include microcomputers and shared (often expensive) resources such as laser printers and large hard disks. Most (modern) LANs can support a wide variety of computers and other devices. Each device must use the proper physical and data-link protocols for the particular LAN, and all devices that want to communicate with each other on the LAN must use the same upper-level communications protocol. Although single LANs are geographically limited (to a department or an office building, for example), separate LANs can be connected to form larger networks. Similar LANs are linked by bridges, which act as transfer points between networks; dissimilar LANs are linked by gateways, which both transfer data and convert it according to the protocols used by the receiving network.

The devices on a LAN are known as nodes, and the nodes are connected by cabling through which messages are transmitted. Types of cables include twisted-pair wiring, coaxial cable, or fibre-optic cable. Nodes on a LAN can be wired together in any of three basic topologies, known as bus, ring, and star. As implied by their names, a bus network is more or less linear, a ring network forms a loop, and a star network radiates from a central hub.

To avoid potential collisions when two or more nodes attempt to transmit at the same time, LANs use either contention and collision detection or token passing to regulate traffic.

WAN
It is a computer network that covers a wide geographical area, usually over telephone lines, as compared to a local area network, which operates in a single company or institution. The Internet is an interconnected web of WANs.

MAN


Short for Metropolitan Area Network, a data network designed for a town or city. In...