A Local Area Network (LAN) is a group of computers and associated devices that share a common communications line or wireless link. Typically, connected devices share the resources of a single processor or server within a small geographic area. A LAN is useful for sharing resources like files, printers, games or other applications. A LAN in turn often connects to other LAN’s, and to the Internet or other WAN.
Components of LAN:
A LAN is made up of three basic elements:
- A. The hardware which is connected to form the LAN.
- B. The software (or programs) which is accessed through the LAN.
- C. The users, who create, work with and manage the various files.
Each of these elements can be divided into a number of components.
A. Hardware Components:
A LAN can be thought of as a system composed of a series of building blocks. These blocks can be added and configured as needed. Some of basic hardware components of LAN’s are:
1. Networking Interface Card (NICs):
A network interface card (NIC) is a circuit board or card that is installed in a computer so that it can be connected to a network. Each networked device contains a Network Interface Card. The NIC may be a separate board installed into a computer’s slot, or it may be built into the motherboard.
A network server is a computer designed to process requests and deliver data to other (client) computers over a local network or the Internet. A server may be three types:
- File Server: A file server is a computer that stores files, is attached to a network, and provides shared access of those files to multiple workstation computers.
- Print Server: A print server is a device that connects printers to client computers over a network. It accepts print request from the computers and sends the jobs to the appropriate printers over the LAN.
- Communication Server: A communication server is a computer system designed to handle a wide range of communications-based applications.
A station is a computer that is connected with a server computer over the LAN, and communicate with other devices connected with it.
A common connection point for devices in a network. Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports. When a packet arrives atone port, it is copied to the other ports so that all segments of the LAN can see all-packets.
A switch is like a hub in that it is a central point for connecting network cables; however, a switch is able to receive a packet and transmit it to only the destination computer.
Routers make the connection to the Internet for LANs. They use a configuration table to decide where packets should go.
7. Access point:
A hardware device or a computer’s software that acts as a communication hub for users of a wireless device to connect to a wired LAN.
8. Power Supply:
Both wired and wireless networks need a power supply. A wireless network uses the current to generate radio waves. A cabled network sends data interpreted as an electronic pulse.
A network connector refers to any device that used to connect many LAN connection with the hardware of the computer.
10. Shared Peripheral Device:
A peripheral device is any device—such as a printer, hard disk drive, CD-ROM drive or modem—that is connected to and controlled by a computer. Any or all of these devices can be accessed by multiple users when connected to a LAN in the proper manner.
B. LAN Software:
Once the physical building blocks of the LAN are put into place, the next step is to make them functional. Software is needed for devices to function cooperatively and effectively on the LAN. There are three categories of software found on a LAN:
- The operating system of each attached server: The server operating system is considered to be the brains of the network:
- The operating system of each attached station: All PCs require an operating system to function.
- Applications software accessed by LAN users: Applications software is those software, which are used to perform a specific task. The most common business applications are word processing, spreadsheet analysis and database management.
Groupware: A second type of application software has been introduced for the LAN environment— groupware. Groupware refers to programs that help people work together collectively while located remotely from each other.
Client/server computing: In client/ server computing, the applications software is created and sold for use expressly on a LAN. Client/server software has two distinct parts—the client part which runs on the user’s station and the server part which is installed on the file server.
C. The People:
Among the most important elements of a LAN are the people. The purpose of a LAN is to allow the sharing of resources. This sharing is done by people—making them an integral part of the structure.
With any LAN there are two groups of people involved—those who use the resources and those who manage the resources.
- The users: A user is defined as a person who makes use of the network resources.
- Network Administrator: The network administrator is the individual responsible for maintaining the LAN. It is essential that the administrator have a good understanding of how the network is put together and how it functions.
A LAN consists of a group of computers and devices connected by switches and hubs. For this LAN to gain access to the Internet it must contain a router. The speed of the network greatly depends on the configuration of the switches and hubs.