Simulation and implementation of clock synchronisation in transputer networks

A clock synchronisation algorithm based on the exchange of timestamped messages, with unpredictable delays, between neighbours in a transputer network was presented by the author in 1991. This algorithm creates and maintains a global time reference, to be used in hard real-time applications, for all nodes of a transputer network of any topology. This global timebase is obtained by periodic filtered correction of the value and rate of each local clock of a node, based on the timestamps received from its neighbours. The optimal values for the two parameters alpha and beta of this filter were still unknown. Simulations by Hoekstra in 1991 have shown that although a save [sic] choice can be made in any case, an optimal choice depends on the topology of the network. The algorithm has been implemented and measurements have been pelformed on a transputer network ring of three nodes at the University Twente. It turned out that the optimal choice for alpha and beta, found by simulation, worked well in the implementation.