Definition

A computer network that spans a relatively small area. Most LANs are confined to a work group, single building or group of buildings. LANs are capable of transmitting data at very fast rates through digital means and the use of data packets. Transmission is much faster than the typical WAN (Wide Area Network); but the distances are limited, and there is also a limit on the number of computers that can be attached to a single LAN.  However, one LAN can be connected to other LANs over any distance typically through the use of a WAN. (Webopedia, 2000)

Components and characteristics

    Type

• Peer-to-peer

• Client/server

    Topology

• Bus
• Star
• Ring
• Mesh
• Hybrid

    Channel

• Unshielded twisted pair (UTP)
• Shielded twisted pair (STP)
• Thin coaxial cable (Thinnet)
• Thick coaxial cable (Thicknet)
• Fiber Optic
• Microwave
• RF (Radio Frequency)
• Infrared

    Architecture

• Ethernet
      10BaseT = UTP
      10Base2 = Thin Ethernet (coax)
      10Base5 = Thick Ethernet (coax)
      10BaseF = Fiber Optic
• Token ring
• Localtalk
• ARCnet
• FDDI

    Network protocol

• TCP/IP
• IPX/SPX
• NetBEUI
• AppleTalk
• DLC

    Network Operating System (software)

• Microsoft NT
• Microsoft Windows 2000/XP
• Novell NetWare
• Microsoft Windows 95/98/ME

Hardware

    File server

A computer and storage device on a network dedicated to storing files. (Webopedia, 2000)

    Print server

A computer on a network that manages one or more printers. Other computers on the network send their print jobs to the print server where they are stored and then printed.

    Communications server

A computer on the network dedicated to managing communications between the LAN and other networks.

    Hub

A common connection point for devices in a network. Hubs are commonly used to connect different segments of a LAN. Packets arriving at a hub are copied and sent to all ports on the hub. All ports can see all data packets when using a hub (unless it is the uncommon switching-type hub). (Webopedia, 2000)

    Bridge

A device that connects two LANs, or two segments of the same LAN. The two LANs being connected can be alike or dissimilar. For example a bridge can connect an Ethernet with a Token-Ring network. Unlike routers, bridges are protocol-independent. They simply forward packets without analyzing and re-routing messages. Consequently they are faster than routers, but also less versatile. (Webopedia, 2000)

    Router

A device that connects any number of LANs. Routers determine where packets go and forward them through the best route. They also communicate with each other through the network. Routers do not translate or convert protocols. (Webopedia, 2000)

    Switch

A device that connects any number of LANs or LAN segments. Switches are similar to routers except that they forward any protocol. They do not communicate with one another, so do not determine the best routing. Switches are generally faster than routers, but less intelligent.

Gateways translate between one network topology (hardware and/or software) and another. For example between TCP/IP and IBM’s SNA.

Reference: Webopedia. (2000, September 24). Available: webopedia.internet.com (September 24, 2000).

See also:
        Network Management Services

© Copyright 2000 Raymond S. Kulzick. All rights reserved. 000924.