The redundancy can be applied on every technical area and describes the additional existence of functionally identical or similar resources. In a undisturbed regular operation, they are generally not needed, in case of defect, they take over the functions of the broken piece and thus maintain operations. This leads to an improved operational and failure safety. Components of a computer or a network may be redundant, in case of failure, these components are used to replace the primary sources (n+1-redundancy). Example: two independent power supplies for a Data Centre. If one power supply fails, the other will ensure the power supply for the Data Centre in order to guarantee an uninterrupted operation.