Question : VLAN

What is VLAN.How it works.Why it is used for.Any example to explain the use of VLAN.?

Answer : VLAN

A VLAN is a grouping of systems into a logical broadcast domain.  It can be used to reduce the number of broadcasts on the network, by keeping broadcasts isolated to the VLAN from where it originated.  The VLAN groupings could be physical (i.e. a floor in a building), or logical (i.e all the people on a particular server).  A routing device is necessary to connect the VLANs.  

It also makes network changes easier, as you can connect one port of a switch into any given VLAN/Segment instead of moving cables around.  This alone can make it worthwhile.