Reaching strong consensus in the presence of mixed failure types

Abstract

The Strong Consensus (SC) is a variant of the conventional distributed consensus problem. The protocol designed for the SC problem requires that the agreed value among fault-free processors be one of the fault-free processor's initial value. The SC problem is re-examined with the assumption of mixed failure types (also referred to as the hybrid fault model). Compared with the features of the existing protocols, the underlying network topologies of the proposed protocol do not have to be fully connected, the mixed failure types can be tolerated, and no prior information of the system's faulty status is required. The proposed protocol can tolerate a maximum number of faults to enable each fault-free processor to reach an agreement with a minimum number of message exchanges. (C) 1998 Published by Elsevier Science Inc. All rights reserved.