Broadcasting messages in fault-tolerant distributed systems: the benefit of handling input-triggered and output-triggered suspicions differently

This paper investigates the two main and seemingly antagonistic approaches to broadcasting messages reliably in fault-tolerant distributed systems: the approach based on reliable broadcast, and that based on view synchronous communication (or VSC for short). While VSC does more than reliable broadcast, this has a cost. We show that this cost can be reduced by exploiting the difference between input-triggered and output-triggered suspicions, and by replacing the standard VSC broadcast primitive by two broadcast primitives, one sensitive to input-triggered suspicions, and the other sensitive to output-triggered suspicions.