Local Area Network (LAN)
LAN is a privately owned network of an organization. It is used to connect a computer with other hardware, such as a printer, at home or in an office. The range of LAN is restricted to a few kilometers only. This type of network is useful when you want to connect computers of two different departments in a building. The data transfer rate in LAN is up to 10 GB/s. High transmission rates are possible in LAN, because of the short distances between the various computer networks. This makes LAN a high-speed and fault-tolerant data network (LAN works properly even if any error occurs). LAN provides the ability to the users to share and access the resources and applications. The major advantage of LAN is to provide communication among users through e-mail and other applications.
LAN consists of Network Interface Cards (NICs), which are fitted on the expansion slot of the motherboard inside computers; a cable (or an equivalent wireless connection) to connect the computers together; a protocol software to transfer data from one computer to another; a user interface software to connect users to the network; and an operating system to help a user to share resources, such as files and printers. LAN is a transmission system that allows a large number and a variety of computing devices to exchange information at high speeds, over limited distances. These devices may range from large mainframe systems to personal computers and peripherals (devices). LAN software identifies the input and instructs the network devices that how to perform. It also enables the users to communicate with each other using e-mail. Beside these, it also enables the users to share printers and storage devices and access processors, data, or programs which are located centrally. LAN users may also access other LANs. Due to the complexity of computer communications, LAN protocols are divided into several hierarchical levels. This hierarchical structure is called a protocol stack. Nowadays, LANs have gained the popularity due to enabling the users to share their computing resources electronically with the hardware, such as printers and CD-ROM drives, and application programs. Nowadays, LAN inter-networks are powerful, flexible, and easy to use, but remember that they incorporate several technologies, such as Ethernet, Token Ring, Token Bus, and FDDI that must work together flawlessly. Now, let’s discuss these technologies of LAN in detail.