Most fault-tolerant algorithms are designed assuming that out of n components, no more than t can be faulty. For example, solutions to the Consensus problem are usually developed assuming no more than t of the n processes are faulty, where “being faulty” is specialized by a failure model. We call this the t of n assumption (also known as threshold model). It is a convenient assumption to make. For example, bounds are easily expressed as a function of t: if processes can fail only by crashing, then the Consensus problem is solvable when t < n if the system is synchronous and when t < 2n if the system is asynchronous extended with a failure detector of the class ◊W. [5.5], [5.1]