Fault-tolerant Clock Synchronization using Precise Time Protocol Multi-Domain Aggregation

Abstract

Distributed real-time systems often rely on timetriggered communication and task execution to guarantee endto-end latency and time-predictable computation. Such systems require a reliable synchronized network time to be shared among end-systems. The IEEE 1588 Precision Time Protocol (PTP) enables such clock synchronization throughout an Ethernet-based network. While security was not addressed in previous versions of the IEEE 1588 standard, in its most recent iteration (IEEE 1588(IEEE -2019, several security mechanisms and recommendations were included describing different measures that can be taken to improve system security and safety. One proposal to improve security and reliability is to add redundancy to the network through modifications in the topology. However, this recommendation omits implementation details and leaves the question open of how it affects synchronization quality.This work investigates the quality impact and security properties of redundant PTP deployment and proposes an observation window-based multi-domain, PTP end-system, design to increase fault-tolerance and security. We implement the proposed design inside a discrete-event network simulator and evaluate its clock synchronization quality using two test-case network topologies with simulated faults.

The FORA European Training Network on Fog Computing for Robotics and Industrial Automation

“…The FORA FCP provides platform services for assuring the safety, security, and dependability of the FCP utilizing virtualization of computation and communications. The FCP implements the Precise Time Protocol Multi-Domain Aggregation for safe and secure clock synchronizations [30]. The security services are implemented as the lightweight authentication protocols for secure and efficient TLS Session Resumption, rTLS [31] and a host intrusion detection system integrated to the FCP [18].…”

Impact Analysis of Time Synchronization Error in Airborne Target Tracking Using a Heterogeneous Sensor Network

“…Synchronization based on the global navigation satellite system (GNSS) is a typical solution, in which accurate time sources from satellites are used as the reference timing. In the context of time distribution, one-pulse-per-second (1-PPS) synchronizing signals from global positioning system (GPS) or GNSS receivers or synchronization protocols [6][7][8][9][10][11][12][13][14][15][16][17][18] allow local sensors to be aligned across the network through communication [17]. Although synchronization directly through GNSS clocks facilitates the realization of precise time accuracy, it requires additional equipment with access to the satellite signal from all local sensors.…”

“…To address concerns regarding GNSS reliability, it is necessary to use timing systems that do not directly rely on local GNSS receivers. An alternative is to use fault-tolerant clock synchronization based on redundant clock sources [8][9][10] or receiver-independent time synchronization [20].…”