PADRE: a Protocol for Asymmetric Duplex REdundancy

D. Essamé, J. Arlat and D. Powell



Safety and availability are issues of major importance in many critical systems. Ensuring simultaneously both attributes is sometimes difficult. Indeed, the introduction of redundancy to increase the overall system availability can lead to safety problems that would not otherwise exist. In this paper, we present a protocol for duplex redundancy management in critical systems that aims to increase the system availability without jeopardizing its safety. An application to a fully-automated train control system is described.