Group13_Avani:How do you think LAN works?

A local area network (LAN) is a group of computers and associated devices that share a common communications line or wireless link and typically share the resources of a single processor or server within a small geographic area (for example, within an office building). A local area network may serve as few as two or three users (for example, in a home network) or as many as thousands of users (for example, in an FDDI network).
Major local area network technologies are:

1. Ethernet
2. Token Ring
3. FDDI (Fiber Distributed Data Interface)

Ethernet: Ethernet is the most widely-installed LAN technology. An Ethernet LAN typically uses coaxial cable or special grades of twisted pair wires. Ethernet is also used in wireless LANs.

Token Ring: The Token Ring is the second most widely-used protocol on local area networks after Ethernet. It is a LAN in which all computers are connected in a ring or star topology and a bit- or token-passing scheme is used in order to prevent the collision of data between two computers that want to send messages at the same time.

FDDI: Fiber Distributed Data Interface is a set of ANSI and ISO standards for data transmission on fiber optic lines in a LAN that can extend in range up to 200 km. FDDI is frequently used on the backbone for a wide area network (WAN).

Working of LAN: Various topologies are possible for broadcast LANs.
1. The first one is bus (i.e linear cable) network. In this at instant atmost one machine is the master and is allowed to transmit. All other machines are required to refrain from sending. An arbitration mechanism is needed to resolve conflicts when two or more machines want to transmit simultaneously.

2. The second one is ring. In a ring, each bit propagates around on its own, not waiting for the rest of the packet to which it belongs. Typically each bit circumnavigates the entire ring in the time it takes to transmit a few bits, often before the complete packet has even been transmitted.

Typically, a suite of application programs can be kept on the LAN server. Users who need an application frequently can download it once and then run it from their local hard disk. A user can share files with others at the LAN server; read and write access is maintained by a LAN administrator. A LAN server may also be used as a Web server. In some situations, a wireless LAN may be preferable to a wired LAN because it is cheaper to install and maintain.