Work-In-Progress: Safe and Secure Configuration Synthesis for TSN using Constraint Programming

Time-Sensitive Networking (TSN) extends IEEE 802.1 Ethernet for safety-critical and real-time applications in several areas, e.g., automotive, aerospace or industrial automation. However, many of these systems also have stringent security requirements, and security attacks may impair safety. Given a TSN-based distributed architecture, a set of applications with tasks and messages, as well as a set of security and redundancy requirements, we are interested to synthesize a system configuration such that the real-time, safety and security requirements are satisfied. We use the Timed Efficient Stream Loss-Tolerant Authentication (TESLA) low-resource multicast authentication protocol to guarantee the security requirements, and redundant disjunct message routes to tolerate link failures. We consider that the tasks are scheduled using static cyclic scheduling and that the messages use the time-sensitive traffic class in TSN, which relies on schedule tables (called Gate Control Lists, GCLs) in the network switches. A configuration consists of the schedule tables for tasks as well as the disjoint routes and GCLs for messages. We propose a Constraint Programming-based formulation for this problem and we evaluate it on several test cases.

I. Introduction

Many modern Cyber-Physical Systems (CPSs) are becoming increasingly more interconnected with the outside world opening new attack vectors [1], [2] that may also compromise safety. Therefore, the security aspects should be equally important to the safety aspects. Time-Sensitive Networking (TSN) [3], which is becoming the standard for communication in several application areas (e.g. automotive to industrial control), is a set of amendments to the IEEE 802.1 standards, equipping Ethernet with the capabilities to handle real-time mixed-criticality traffic with high bandwidth. Available traffic types are Time-Triggered (TT) traffic for real-time applications, Audio-Video Bridging (AVB) for applications that need bounded latency, but do not have hard real-time requirements, and Best-Effort (BE) traffic for non-critical applications.