IEEE 1588 for redundant ethernet networks

Ethernet technologies are widely deployed across different industry sectors. Many applications have the need for accurate time synchronization as well as redundant communication links. The IEEE 1588 Precision Time Protocol was designed to deliver accurate synchronization in network environments using Ethernet technology, but the combination of IEEE 1588 with redundant Ethernet is known to be difficult. This paper introduces a combination solution for IEEE 1588 and redundant Ethernet that is able to increase the average synchronization accuracy compared to non redundant IEEE 1588 synchronization. For this purpose, the main accuracy limiting factor, the clock drift in transparent clocks, has been analyzed and measured. Subsequently, we present approaches that can reduce these undesired effects and improve the average synchronization accuracy. Further, the accuracy improvement of two of our approaches have been demonstrated using a redundant Ethernet implementation that is time synchronized.