Fast consensus under eventually stabilizing message adversaries
Manfred Schwarz, Kyrill Winkler, Ulrich Schmid · 2016
This paper1 is devoted to deterministic consensus in synchronous dynamic networks with unidirectional links, which are under the control of an omniscient message adversary. Motivated by unpredictable node/system initialization times and long-lasting periods of massive transient faults, we consider message adversaries that guarantee periods of less erratic message loss only eventually: We present a tight bound of 2D + 1 for the termination time of consensus under a message adversary that eventually guarantees a single vertex-stable root component with dynamic network diameter D, as well as a simple algorithm that matches this bound. It effectively halves the termination time 4D + 1 achieved by the fastest consensus algorithm known so far. We also introduce a generalized, considerably stronger variant of our message adversary, and show that our new algorithm, unlike the existing one, still works correctly under it.