If we are based on a concrete definition, it is a functional building composed of transmission equipment, software and communication protocols and a subsidiary or radioelectric infrastructure that allows the transmission of data between the various components.
From a topological point of view, it can be shaped like a star, a linear segment or bus, a loop or ring, a star (hierarchical) or mesh. See an article on network topologies.
From a typological point of view, the architecture is respectively qualified as LAN (Local Area Network), MAN (Metropolitan Area Network) and WAN (Wide Area Network) when the network covers a local area (<1 km), metropolitan (< 100 km) and long distance.
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