PTP Dataset Analysis Library (PTP-DAL)

Overview

The PTP-DAL project consists of a Python package and scripts to investigate synchronization algorithms applied on top of the IEEE 1588 precision time protocol (PTP). The project focuses on offline analysis by processing datasets of timestamps collected from real hardware. Using this strategy, the user can process the same dataset with varying parameters and algorithms until achieving the best synchronization performance.

The PTP-DAL library implements several algorithms, such as packet selection, least-squares, and Kalman filtering. These are applied independently on the timestamps provided by a given dataset. This approach is analogous to running several algorithms in parallel in a real-time implementation.

After processing the selected algorithms, PTP-DAL outputs a comprehensive set of results comparing the synchronization performance achieved by each algorithm, with timing metrics such as the maximum absolute time error (max|TE|), maximum time interval error (MTIE), and so on. Additionally, the results include analyses of several aspects of the PTP network and the surrounding environment, such as the packet delay variation (PDV), PTP delay distributions, and temperature variations.

The project was specifically developed to analyze datasets of timestamps generated by the FPGA-based PTP synchronization testbed developed by LASSE - 5G & IoT Research Group. This testbed has been detailed in various publications, including:

  1. “Clock Synchronization Algorithms Over PTP-Unaware Networks: Reproducible Comparison Using an FPGA Testbed,” in IEEE Access, 2021.

  2. “5G Fronthaul Synchronization via IEEE 1588 Precision Time Protocol: Algorithms and Use Cases,” Ph.D. thesis, Federal University of Pará, Dec. 2020.

  3. “Testbed Evaluation of Distributed Radio Timing Alignment Over Ethernet Fronthaul Networks,” in IEEE Access, 2020.

  4. “An FPGA-based Design of a Packetized Fronthaul Testbed with IEEE 1588 Clock Synchronization,” European Wireless 2017.

In particular, Chapter 4 from reference [2] provides the most comprehensive description of the testbed and the dataset acquisition process, while Chapter 3 covers the algorithms supported by the PTP-DAL project.

The adopted datasets of timestamps comprise a large number of PTP two-way exchanges. Each exchange corresponds to a row in the dataset and includes a set of timestamps. More specifically, each row consists of the four timestamps involved in the two-way PTP packet exchange (t1, t2, t3, and t4), as well as auxiliary timestamps. The auxiliary timestamps indicate the actual one-way delay of each PTP packet and the true time offset affecting the slave at that moment. Ultimately, this supplemental information allows for analyzing the error between each time offset estimator and the actual time offset experienced by the slave clock at any point in time.

The datasets produced by the testbed can be made available on demand. If you are interested in exploring PTP-DAL using datasets acquired from LASSE’s PTP synchronization testbed, please read the dataset access section and contact us directly over email. Otherwise, this repository contains a simulator capable of generating compatible datasets through simulation.

Getting Started

Indices and tables