This diagram was published in the military memorandum RM-3420-PR “On Distributed Communications - I Introduction to Distributed Communications Networks”. Paul Baran is considered to be one of the precursor architects of the Internet, and this memorandum laid the conceptual foundations of computer systems architecture, which is still used today. Computer systems are said to be redundant if they present the same technical components and data sets several times in parallel, in order to protect against any risk of breakdown or destruction of the hardware storing the data. This concept comes from engineering, where, for example, the cables suspended from a bridge are multiplied to increase the safety of the entire bridge system. The bridge does not collapse if a single cable falls, because the cable is supported by others in its load-holding function. The data will not be destroyed and can still navigate by other routes in the event of an attack on a centre, if a network based on redundancy is built.