Let's talk!

Local Area Networks

  • click to rate

    what is LAN?

    Local area networks (LANs) have become commonplace in the information age. The introduction of low-cost computers, along with the need to share information and hardware resources, in an office environment led the way to the development of inexpensive LAN technologies.

    LAN technologies are designed to interconnect computers across short distances (e.g., within a single building or room). Today’s LANs are inexpensive, highly reliable, and easy to install and maintain. To connect a computer to a LAN, a computer must have an interface card. The computer views this interface card as any other I/O device. Data sent to the interface card are transmitted onto the communication medium (copper wire, coax cable, optical fiber, or through the air at a given radio frequency), where it is then received by another computer attached to the same medium. The communication medium used is transparent to the application.

    LANs have become so successful because they have changed the economics of computing. It is now possible to use inexpensive computers to share access to common resources such as application software, large storage banks (disks), and printers. LANs also enable users to share information, thereby facilitating collaborative and group work.

    Perhaps the most popular LAN technology is Ethernet. Ethernet uses a broadcast mechanism to communicate between different stations on the LAN. A station wishing to communicate to another station simply listens to the channel, and if no one is sending, it sends its data (along with the numerical address of the station it wants to receive the data) onto the communication medium. Every station listens to the communication medium and, if it hears a piece of information transmitted with its address, it receives the information and passes it along to the appropriate application program.