Identifying Different Types of Networks
There are many types of computer networks that are characterised on the basis of size or purpose. The size of a network is expressed depending on the geographical area it occupies and the number of computers that are a part of the network. The size of a network can vary from a few computers in a room to millions of computers spread across the globe.
On the basis of size, networks are classified under the following categories:
Local Area Network (LAN)
It is a network that is confined to a small geographical area such as a school, office, or multiple offices within a campus. However, a single LAN can be connected to other LANs over long distance via telephone lines and radio waves. The LAN is a private network which can restrict communication to the nodes within the network and prevent it from reaching the Internet.
Metropolitan Area Network (MAN)
MAN is a large, high-speed computer network that usually spans a large campus or an entire city. A MAN usually interconnects multiple LANs using high-capacity fibre-optical links. MAN covers the geographical area larger than the LAN but smaller than the area covered by a WAN (Figure 3). Companies that use MAN usually have several branches within a city such as banks, local ISPs, cable television companies and local telephone companies. Metro Ethernet is one of the latest forms of MAN.
Wide Area Network (WAN)
It is a network that spans over a large geographical area, such as a country or the entire world. A WAN can contain multiple smaller networks, such as LANs and MANS. WANs are used by large organisations to interconnect LANs at offices in different countries. The Internet is the biggest public WAN and a network of ATMs is a private WAN.
Virtual Private Network (VPN)
It is a type of network that allows computers or an entire network to connect to each other over the Internet securely. VPN is based on the client-server architecture so it consists of a VPN client and VPN server and the software that enables secure connections. VPN uses different security tools such as tunneling protocol. The tunneling protocol creates a tunnel between two devices and encrypts all the information in the tunnel.
VPNs are mostly used by organisations to protect sensitive data. They use tunneling protocols such as Point-To-Point Tunneling (PPTP) and Secure Socket Layer (SSL) for secure authentication and encryption of the network traffic.