Types of Network
Computer Networks classified into three classes regarding the size, distance and the structure namely: LAN (Local Area Network), MAN (Metropolitan Area Network), WAN (Wide Area Network) and PAN (Personal Area Network).
• A personal area network, or PAN, is a computer network that enables communication between computer devices.
• PANs can be wired, such as USB or FireWire, or they can be wireless, such as infrared, ZigBee, Bluetooth and ultra wide band (UWB).
• The range of a PAN typically is a few meters. Examples of wireless PAN, or WPAN, devices include cell phone headsets, wireless keyboards, wireless mice, printers, bar code scanners and game consoles.
• A Local Area Network is a privately owned computer network covering a small Networks geographical area, like a home, office, or groups of buildings e.g. a school Network.
• We can use different types of topologies through LAN.
• LAN networks are also widely used to share resources like printers, shared hard-drive etc.
• The size of LAN is usually small. The various devices in LAN are connected to central devices called Hub or Switch using a cable.
• Now-a-days LANs are being installed using wireless technologies.
• LAN offers high speed communication of data rates between 4 to 16 megabits per second (Mbps).
• In this network one can become a server serving all the remaining computers called clients. Software can be stored on the server and it can be used by the remaining clients.
• Without internet access, it is possible to connect all the workstations in a building with each other locally.
• It is easy to share common resources like printers with LAN.
• Privacy Violations: The LAN administrator has the rights to check personal data files of each and every LAN user. Moreover he can check the internet history and computer use history of the LAN user.
• Data Security Threat: Unauthorised users can access important data of an organization if centralized data repository is not secured properly by the LAN administrator.
• Covers Limited Area: Local Area Network covers a small area like one office, one building or a group of nearby buildings.
It is basically a bigger version of LAN. It is designed to extend over the entire city. MANs extend beyond 100 KM. MANs are usually owned by large organizations to interconnect its various branches across a city. MAN comprises combination of different hardware and transmission media. It can be single network such as a cable TV network, or it is a means of connecting a number of LANs into a larger network so that resources can be shared LAN to LAN as well as device to device.
• It is extremely efficient and provides fast communication via high-speed carriers, such as fibre optic cables.
• It provides a good back bone for large network and provides greater access to WANs.
• The dual bus used in MAN helps the transmission of data in both directions simultaneously.
• A MAN usually encompasses several blocks of a city or an entire city.
• More cable is required for a MAN connection from one place to another.
• It is difficult to make the system secure from hackers and spying.
A wide area network (WAN) is a telecommunication network. WANs connect LANs that may be on opposite sides of a building, across the country or around the world. Computers connected to a Wide Area Networks are often connected through public networks, such as the telephone system. They can also be connected through leased lines or satellites. The largest WAN in existence is the Internet.
• It covers a large geographical area.
• It shares software and resources with connecting workstations.
• Messages can be sent very quickly to anyone else on the network. These messages can have picture, sounds or data included with them (called attachments).
• Everyone on the network can use the same data. This avoids problems where some users may have older information than others.
• It needs a good firewall to restrict outsiders from entering and disrupting the network.
• Once set up, maintaining a network is a full-time job which requires network supervisors and technicians to be employed.
• Security is a real issue when many different people have the ability to use information from other computers. Protection against hackers and viruses adds more complexity and expense.