Standard Ethernet technology does not allow data to be transmitted consistently in real time, requiring the use of dedicated real-time fieldbuses. But these buses rely on special hardware and do not comply with the IEEE 802.1 and 802.3 network standards, preventing optimal integration.

The Fraunhofer developers believe that TSN (Time-Sensitive Networking) will allow critical real-time messages to be transmitted deterministically throughout networks using standard Ethernet hardware. They say that the joint transmission of real-time and normal Ethernet communications will lead to completely new approaches for the convergence of production and IT networks.

“The synchronisation of time is an important TSN element, as deterministic data delivery demands that all devices throughout the network have the same understanding of time, as defined in IEEE 802.1AS-rev,” explains Dr Frank Deicke, who leads the IPMS’ wireless microsystems activities. “Traffic shaping and scheduling enables the parallel transmission of datastreams with both soft and hard real-time requirements, as well as so-called best-effort traffic.

The IEEE standard already defines a way of prioritising time-critical datastreams. However, in the automotive sector, for example, there are applications that need lower jitter and latency. The IEEE 802.1Qbv sub standard establishes criteria for fixed cyclic transmission windows that allow for the unimpeded transmission along an entire path.