A network is any number of independent computer systems that are interconnected so that data exchange is possible. For this to happen, networked systems must be connected logically in addition to physically. The latter is established by special network protocols, such as TCP (Transmission Control Protocol). Even just two computers connected to each other can be classified as a network.
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Networks are set up to transfer data from one system to another, or to share resources, such as servers, databases, and printers on the network. Depending on the size and range of the computer network, you can differentiate between different network dimensions. The most important network types include:
Personal Area Networks (PAN)
Local Area Networks (LAN)
Metropolitan Area Networks (MAN)
Wide Area Networks (WAN)
Global Area Networks (GAN)
The physical connection, which these network types are based on, can be cable-connected or implemented based on wireless technology. Physical communication networks often form the basis for several logical communication networks, so-called virtual private networks (VPNs). These use a common physical transfer medium e.g. a glass fiber cable, when transferring data and are assigned to logically different virtual networks by means of tunneling software.
Each type of network was developed for specific areas of application, is based on its own techniques and standards, and brings different advantages and limitations with it.