Design and Implementation of Delay Measurement in PRP and HSR RedBox

This paper introduces a method to measure the propagation delay of SV and GOOSE packets transmission in the network constructed with PRP and HSR RedBoxes. Although IEEE 1588 precision time protocol is preferred in PRP and HSR protocols to fulfil the purpose of time synchronization, of which the implementation is rather difficult in terms of the variety of clock types needed. The duplicate IEEE 1588 synchronization frames are treated separately and HCs are needed to realize the time synchronization instead of OCs when HSR is employed. When it comes to MU, which is sensitive to time synchronization as SV packets are transmitted in a network topology other than point-to-point way, the system is vulnerable due to complexity and topology. By using the method proposed in this paper, the propagation delay of SV and GOOSE packets are measured and stored in the packets. Then devices using these packets could get the propagation delay for further calculation. Implementation and experiment justify the proposed method of measuring propagation delay in terms of accuracy.