Computer is an electronic device which is performs mathematical and logical function at very high speed. In other way we can be defined to computer as a digital and automatic machine which takes input data from user process stores if it necessary and gives output as result. Now a day computer is main part of our life. Without it we can not work anything. Computer provides us very intelligent knowledge and talent performance. It makes our life very easy and successful. Many difficult works are easy now from computer. It saves our important time also. It can do anything which is impossible for human being.
LAN - Local Area Network
A LAN connects network devices over a relatively short distance. A networked office building, school, or home usually contains a single LAN, though sometimes one building will contain a few small LANs (perhaps one per room), and occasionally a LAN will span a group of nearby buildings. In TCP/IP networking, a LAN is often but not always implemented as a single IP subnet