Common implementation and interoperability challenges : focus on clock control for QBv on Linux-based end stations

Interoperability is essential for a successful market adoption of TSN. Plugfest experiences from multi-vendor TSN-networks show the impact of varied interpretations of IEEE standards and common implementation issues on interoperability. We investigate challenges like negative meanLinkDelays, IEEE802.1AS-message priority classes and the implementation of time-triggered sending in combination with time synchronization (like LinuxPTP). Our study reveals the importance of controlling the LocalClock without interfering with the required free-running LocalClock as mandated by the time synchronization standard. We present solutions required for standard-compliant implementations usable for single clock devices (e.g. end station based on Linux and i210).