Based on performance and structure network can be classified into 3 category.
· Local area network
· Metropolitan area network
· Wide area network
Local area network: In our daily life we are using local area network (LAN). Small-medium offices, court and trade this network has been used. The main objective of this network is to sharing resources and data among devices. In easy word same house or close when a number of computers are connecting through network card or cable is called local area network (LAN). As a result one computer can share its hardware and software resource with other PC. In Hardware including printer, CD-ROM, and hard disk drive etc. Application, utility and files are known as software.
Metropolitan area network: Metropolitan area network is consists of a number local area network. Through this network with high speed the network can transfer their data. The main user is various govt. offices. Suppose in every police station network of Dhaka city created a strong network is called metropolitan area network. The difference between local area network and metropolitan area network is the speed. It can be used to connect various offices of various companies.
Wide area network: Wide area network is consisting of LAN or MAN which is situated in geographical area. This network is building through using telephone company cable. That’s why the speed of wide area network is very slow. It uses special device and technology to connect LAN and man. The planning to build WAN is harder than LAN.
Modem: Modem is the signal converter that connects the communication between computer and telephone network. It helps to communicate so that it originates from the word modulation/ demodulation. We can understand from the name of modem that it functions as a modem modulator and demodulator.