The term infrastructure is used wherever people, machines, information or energy share common structures. It can be the infrastructure of companies, road infrastructure, water supply, energy networks, railroads or communication networks.
In information technology, infrastructure represents the physical concept with which computers and workstations are interconnected and which supports signal processing and flow. The infrastructure consists of the transmission media, the active and passive components, and the software that provides for the transmission of information between the various components. The transmission media can be transmission cables around optical fibers, but also radio links as in WLANs or radio links of directional radio links or satellite communication. As far as the active and passive components are concerned, there are routers and switches, repeaters, regenerators, transmitters and control units in which the signals are received, processed and transmitted.
In cloud computing, there is a service for the provision of infrastructure by an IT service provider. In this cloud service - Infrastructure-as-a-Service( IaaS) - all infrastructure components such as the servers, computing power, network capacity, communication devices, etc. are provided to the user.