The “Industrial Edge” project, funded by the German Federal Ministry of Education and Research under grant 01QE2022B, ran from 1 May 2020 to 30 April 2023. Its core objective was to create a software‑based implementation of Time Sensitive Networking (TSN) that could run on standard hardware without dedicated TSN support. The consortium comprised Linutronix GmbH, which led the design and development, Olimex, which supplied STM32MP1‑based evaluation boards, Intel Deutschland GmbH, which provided x86 servers and later acquired Linutronix, and Nexedi GmbH, which contributed the Babel IPv6 routing protocol and will take over the final work package.
The technical effort focused on the IEEE 802.1Qbv standard, which uses Time Division Multiplexing (TDM) to allocate discrete time slots to traffic classes such as Isochron, Management, and Best Effort. TSN relies on precise time synchronization via the Precision Time Protocol (PTP) defined in IEEE 802.1AS‑2011/2020. While TSN is traditionally implemented in hardware, Linutronix’s approach mapped the TSN concepts onto Layer 3 by using IPv6 addresses to determine the appropriate time slot. Linux socket priorities were employed to associate traffic classes with PTP‑synchronised slots, and the existing Linux Traffic Control subsystem was leveraged to perform the mapping. The Babel routing protocol, supplied by Nexedi, enabled dynamic IPv6 address assignment and routing within the test networks.
At the project’s outset, the Linux kernel already contained software implementations of the Time Aware Shaper (TAS) and PTP. Early evaluations on Intel and NXP TSN‑capable hardware revealed that the out‑of‑the‑box software solutions could not match the deterministic performance of hardware‑based TSN. Consequently, Linutronix extended the kernel’s TAS implementation by refining interrupt handling, locking, and timer interfaces to work within the real‑time constraints of the PREEMPT_RT patch. These modifications allowed the software‑based TAS to achieve stable cycle times of up to 1 kHz, a performance level suitable for many industrial control loops. Comprehensive latency and jitter measurements were performed on a mix of low‑cost Ethernet switches and direct 1:1 links, and long‑term reliability tests confirmed the robustness of the solution.
The project’s collaboration was largely conducted virtually due to the COVID‑19 pandemic, and a global chip shortage introduced additional delays. Work package 2, which covered the initial concept and feasibility study, was completed early. The core implementation of software‑based TSN was finished by February 2022, at which point Linutronix was acquired by Intel Deutschland GmbH, resulting in the loss of its SME status. Work package 3 remains unfinished and will be completed without further funding, while work package 4 will be transferred to Nexedi GmbH. The results demonstrate that a purely software‑based TSN stack can provide deterministic Ethernet communication on standard hardware, opening opportunities for consulting, integration, and support services in industrial edge deployments.