An availability network is a fault-tolerant network of devices in which the failure of important components does not result in a total failure of the network, but the most important services remain available and operational. The availability network thus serves to increase operational reliability and, in general, to ensure high availability of the systems and services.
The availability network is used in particular in environments that require a high level of operational reliability or where a failure would result in economic damage, e.g. in flight control , in industrial production and for telecommunications equipment . The safety system of nuclear power plants is also designed as an availability network. This is also referred to as the degree of redundancy (e.g. 4 emergency power diesels, only 2 of which are required for incident control).