An upper and a lower bound for tick synchronization

The tick synchronization problem is defined and studied in the semisynchronous complete network with n processes. An algorithm for the tick synchronization problem enables each process to make an estimate of real time close enough to those of other processes. It is assumed that the (real) time for message delivery is at most d and the time between any two consecutive signs of any process is in the interval [c, 1], where 0<c⩽1. The author defines the precision of a tick synchronization algorithm to be the maximum difference between estimates of real time made by different processes, and proposes it as a worst-case performance measure