An Experimental Platform for Time-Sensitive Networking in Safety-Critical Systems

Kurzfassung

Since the introduction of Integrated Modular Avionics into the world of aeronautics, the question of how to achieve reliable and deterministic communication between distributed components of mixed criticality levels has been answered in multiple ways. Older generation aircraft used federated architectures in which synchronous one-to-many buses connect functionally dependent systems. The increasing number of connected systems lead to the development of the Aircraft Core Data Network (ACDN) where these one-to-many links of different criticality are multiplexed onto asynchronous packetswitched links. Locally, IMA systems use deterministic synchronous IPC such as the APEX API defined in ARINC 653 to communicate between individual applications. The packet-switched networks ensure determinism using TSN techniques such as AFDX. While both domains are well standardized, the mapping between them still remains an implementation detail of the IMA system, which poses limitations on the portability of networked services. In this thesis, a portable partition is created that transparently and deterministically performs this mapping from the IPC ports to the network using only the standardized APIs of ARINC 653, which is available on all modern IMA platforms. It can be extended with user-defined implementations for additional types of networks and TSN schedulers. Further, it features extensive tracing and logging capabilities, providing a platform for easy experimentation with new and existing technologies. To verify the approach and implementation, an evaluation of the performance and real-time properties has been conducted using real hardware and simulation. Portability and extensibility have been demonstrated using pluggable implementations for the XNG and arinc653-linux hypervisors and different platform-specific network interface implementations. During the evaluation, multiple factors were identified that contribute to a complex behavior of the delay and jitter in locally synchronous – globally asynchronous IMA systems.