Efficient Fault-Tolerant Clock Synchronization in Ring Topologies

Many safety-relevant real-time systems require fault-tolerant clock synchronization. For the class of bridge-connected networks with a very small amount of redundant point-topoint links, particularly ring topologies, a new clock synchronization protocol is proposed: "single initiator forward and answer", SFA for short. This solution tolerates (almost) arbitrary behavior of a single faulty bridge, although it requires only two disjoint paths between any pair of bridges.