A comparison of voting strategies for fault-tolerant distributed systems

The problem of voting is studied for both the exact and inexact cases. Optimal solutions based on explicit computation of condition probabilities are given. The most commonly used strategies, i.e. majority, median, and plurality are compared quantitatively. The results show that plurality voting is the most powerful of these techniques and is, in fact, optimal for a certain class of probability distributions. An efficient method of implementing a generalized plurality voter when nonfaulty processes can produce differing answers is also given