LOCAL AREA NETWORK (LAN)

A local area network (LAN) is a communication network that interconnects a variety of data

communicating devices within a small geographic area and broadcasts data at high data transfer

rates with very low error rates. Since the local area network first appeared in the 1970s, its use

has become widespread in commercial and academic environments. It would be very difficult to

imagine a collection of personal computers within a computing environment that does not

employ some form of local area network.

Functions of a Local Area Network

The majority of users expect a local area network to perform the following functions and provide

the following applications:

1)           file serving

2)           database and application serving,

3)           print serving

4)           electronic mail

5)           remote links

6)           video transfers

7)           process control and monitoring

Advantages and Disadvantages of Local Area Networks

Local area networks have several advantages, 1)including hardware and software sharing,

2)workstation survival during network failure,

3)component and system evolution,

4) heterogeneous mix of hardware and software

5) and access to other LANs, WANs, and mainframe computers.

Disadvantages include

1)           complexity,

2)           maintenance costs,

3)           and the fact that the network is only as

strong as the weakest link.

The First Local Area Network – The Bus/Tree

The bus local area network was the first physical design when LANs became commercially

available in the late 1970s, and it essentially consists of a single cable, or bus, to which all

devices attach. Since then, the bus has diminished significantly to the point of near extinction. It

is interesting to note that cable television signals are still delivered by a network bus. Thus,

understanding the bus/tee network is still important.