Data editing: faster convergence for synchronous approximate agreement

The protocol for synchronous approximate agreement presented by D. Dolev, et al., (J. ACM, vol.33, no. 3, pp. 499-516, 1986) exhibits the undesirable property that a fault processor, by the dissemination of a value far removed from the values held by good processors, can delay the termination of the protocol by an arbitrary amount of time. Such behavior is clearly undesirable in a fault-tolerant control system subject to hard real-time constraints. A mechanism is proposed by which discarding data suspected of being from failed processors can lead to quicker, predictable, convergence on an agreement value. Under specific assumptions about the nature of values transmitted by failed processors relative to those transmitted by good processors, Monte Carlo simulation results are presented that illuminate the tradeoff between accelerated convergence and the accuracy of the agreed-upon value.<
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