OSI MODEL

OSI stand for open systems interconnection or OSI model was first proposed by international standard organization (ISO) to solve the multiple problems faced in telecommunication. It is conceptual model of telecommunication networking where the whole process is divided into seven effective layers. The 7 OSI model layers are:-

1- Physical layer
2- Data link layer
3- Network layer 
4- Transport layer
5- Session layer
6- Presentation layer
7- Application layer

WHAT IS NETWORK?

A network consists of two or more computers that are linked in order to share resources (such as printers and Cd's), exchange files, or allow electronic communications. The computers on a network may be linked through cables, telephone lines, radio waves, satellites, or infrared light beams.






Types of Networks-


1. LAN- LAN stands for local area network. It is used to network computers within a limited area like office, school by using the network media.







2. CAN- Can stand for campus area network. Can is an interconnection of local area networks within a limited geographical area. Can is smaller than a wide area network.



3. MAN- Man stand for metropolitan area network, which optimized for larger geographic area than a LAN ranging from several blocks of buildings to entire city.






4. WAN- Wan stand for wide area network that is a network connection of wide area such as the world.






5. PAN- Pan stand for personal area network which is referred to the interconnection of information technology devices mostly up to 10 meters. these interconnected devices might include laptop computer, mobile phones, printers or other devices.