Towards Timing Isolation for Mixed-Criticality Communication in Software-Defined Vehicles

2025-08-19

AI Summary

In software-defined vehicles, mixed-criticality communication faces severe timing isolation challenges due to interference, unpredictable latency, and jitter—especially from concurrent access to the Linux network stack. Method: This paper proposes a full-stack isolation architecture spanning middleware, the network protocol stack, and hardware. It integrates the Data Distribution Service (DDS) framework, fixed-priority non-preemptive scheduling, eXpress Data Path (XDP) bypassing the kernel stack, and dedicated NIC queues to enforce strict temporal isolation between high- and low-criticality traffic. Contribution/Results: The key innovation is an end-to-end deterministic transmission channel that avoids kernel protocol stack contention. Experiments demonstrate that, under intense best-effort traffic interference, real-time traffic maintains sub-millisecond bounded latency and ultra-low jitter—significantly enhancing execution predictability on centralized in-vehicle Linux platforms.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Multiagent Systems: Agent Communication
• Application Domains: Mobility, Driving & Flight

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Virtualization and resource management in Web systems and infrastructures
• Security and Privacy: Large-scale security measurements
• Social Networks and Social Media: Analysis of web-mediated communications, communities, and crowds

Abstract

As the automotive industry transitions toward centralized Linux-based architectures, ensuring the predictable execution of mixed-criticality applications becomes essential. However, concurrent use of the Linux network stack introduces interference, resulting in unpredictable latency and jitter. To address this challenge, we present a layered software architecture that enforces timing isolation for Ethernet-based data exchange between mixed-criticality applications on Linux-based automotive control units. Our approach integrates traffic prioritization strategies at the middleware layer, the network stack layer, and the hardware layer to achieve isolation across the full software stack. At the middleware layer, we implement a fixed-priority, non-preemptive scheduler to manage publishers of varying criticality. At the network layer, we leverage the express data path (XDP) to route high-priority data directly from the network interface driver into critical application memory, bypassing the standard Linux network stack. At the hardware layer, we dedicate a network interface card (NIC) queue exclusively to real-time traffic. We demonstrate how our architecture performs in a Data Distribution Service (DDS)-based system. Our evaluation shows that the approach leads to consistent and predictable latencies for real-time traffic, even under heavy interference from best-effort applications.

Problem

• Ensuring predictable mixed-criticality application execution in Linux-based vehicles
• Mitigating network stack interference causing unpredictable latency and jitter
• Achieving timing isolation for Ethernet communication across software stack

Innovation

• Layered software architecture for timing isolation
• XDP bypasses Linux stack for high-priority data
• Dedicated NIC queue for real-time traffic