Impact of AS6802 Synchronization Protocol on Time-Triggered and Rate-Constrained Traffic

Authors Anaïs Finzi, Luxi Zhao

Thumbnail PDF


  • Filesize: 0.59 MB
  • 22 pages

Document Identifiers

Author Details

Anaïs Finzi
  • TTTech Computertechnik AG, Wien, Austria
Luxi Zhao
  • Technical University of Denmark, Lyngby, Denmark

Cite AsGet BibTex

Anaïs Finzi and Luxi Zhao. Impact of AS6802 Synchronization Protocol on Time-Triggered and Rate-Constrained Traffic. In 32nd Euromicro Conference on Real-Time Systems (ECRTS 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 165, pp. 17:1-17:22, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


TTEthernet is an Ethernet-based synchronized network technology compliant with the AFDX standard. It supports safety-critical applications by defining different traffic classes: Time-Triggered (TT), Rate-Constrained (RC), and Best-Effort traffic. The synchronization is managed through the AS6802 protocol, which defines so-called Protocol Control Frames (PCFs) to synchronize the local clock of each device. In this paper, we analyze the synchronization protocol to assess the impact of the PCFs on TT and RC traffic. We propose a method to decrease the impact of PCFs on TT and a new Network Calculus model to compute RC delay bounds with the influence of both PCF and TT traffic. We finish with a performance evaluation to i) assess the impact of PCFs, ii) show the benefits of our method in terms of reducing the impact of PCFs on TT traffic and iii) prove the necessity of taking the PCF traffic into account to compute correct RC worst-case delays and provide a safe system.

Subject Classification

ACM Subject Classification
  • Networks → Network performance analysis
  • AS6802
  • TTE
  • Modeling
  • Performance analysis


  • Access Statistics
  • Total Accesses (updated on a weekly basis)
    PDF Downloads


  1. Airlines Electronic Engineering Committee. Aircraft Data Network Part 7, Avionics Full Duplex Switched Ethernet (AFDX) Network, ARINC Specification 664. In Aeronautical Radio, 2002. Google Scholar
  2. Anne Bouillard, Laurent Jouhet, and Eric Thierry. Service curves in Network Calculus: dos and don'ts. Research report, INRIA, 2009. Google Scholar
  3. M. Boyer, H. Daigmorte, N. Navet, and J. Migge. Performance impact of the interactions between time-triggered and rate-constrained transmissions in TTEthernet. In European Congress on Embedded Real Time Software and Systems, 2016. Google Scholar
  4. Marc Boyer, Jörn Migge, and Nicolas Navet. An efficient and simple class of functions to model arrival curve of packetised flows. In Proc. of the 1st Int. Workshop on Worst-Case Traversal Time (WCTT), 2011. Google Scholar
  5. Silviu S. Craciunas and Ramon Serna Oliver. Combined task- and network-level scheduling for distributed time-triggered systems. Real-Time Systems, 52(2):161-200, 2016. Google Scholar
  6. J. Diemer, D. Thiele, and R. Ernst. Formal worst-case timing analysis of Ethernet topologies with strict-priority and AVB switching. In Proc. International Symposium on Industrial Embedded Systems (SIES). IEEE Computer Society, 2012. Google Scholar
  7. Fabrice Frances, Christian Fraboul, and Jérôme Grieu. Using network calculus to optimize the AFDX network. In Embeeded Real Time Software and Systems (ERTS), 2006. Google Scholar
  8. Jérôme Grieu. Analyse et évaluation de techniques de commutation Ethernet pour l'interconnexion des systèmes avioniques. PhD thesis, INPT, 2004. Google Scholar
  9. Hermann Kopetz, Astrit Ademaj, Petr Grillinger, and Klaus Steinhammer. The Time-Triggered Ethernet (TTE) Design. 8th IEEE International Symposium on Object-oriented Real-time distributed Computing (ISORC), Seattle, Washington, 2005. Google Scholar
  10. J.Y. Le Boudec and P. Thiran. Network calculus: a theory of deterministic queuing systems for the internet. Springer-Verlag, 2001. Google Scholar
  11. SAE International. SAE AS6802 Time-Triggered Ethernet., 2011. URL:
  12. Miladin Sandić, Ivan Velikić, and Aleksandar Jakovljević. Calculation of number of integration cycles for systems synchronized using the AS6802 standard. In 2017 Zooming Innovation in Consumer Electronics International Conference (ZINC), pages 54-55. IEEE, 2017. Google Scholar
  13. Eike Schweissguth, Peter Danielis, Dirk Timmermann, Helge Parzyjegla, and Gero Mühl. ILP-based joint routing and scheduling for time-triggered networks. In Proceedings of the 25th International Conference on Real-Time Networks and Systems, pages 8-17. ACM, 2017. Google Scholar
  14. Wilfried Steiner. An Evaluation of SMT-based Schedule Synthesis For Time-Triggered Multi-Hop Networks. In RTSS. IEEE, 2010. Google Scholar
  15. Wilfried Steiner. Synthesis of static communication schedules for mixed-criticality systems. In 2011 14th IEEE International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing Workshops, pages 11-18. IEEE, 2011. Google Scholar
  16. Wilfried Steiner, Günther Bauer, Brendan Hall, and Michael Paulitsch. TTEthernet: Time-Triggered Ethernet. In Roman Obermaisser, editor, Time-Triggered Communication. CRC Press, August 2011. Google Scholar
  17. Wilfried Steiner and Bruno Dutertre. Automated formal verification of the TTEthernet synchronization quality. In NASA Formal Methods Symposium, pages 375-390. Springer, 2011. Google Scholar
  18. Wilfried Steiner and Bruno Dutertre. The TTEthernet synchronisation protocols and their formal verification. International Journal of Critical Computer-Based Systems 17, 4(3):280-300, 2013. Google Scholar
  19. Domitian TamasSelicean, Paul Pop, and Wilfried Steiner. Timing analysis of rate constrained traffic for the TTEthernet communication protocol. In 2015 IEEE 18th International Symposium on Real-Time Distributed Computing, pages 119-126. IEEE, 2015. Google Scholar
  20. Daniel Thiele, Philip Axer, and Rolf Ernst. Improving formal timing analysis of switched ethernet by exploiting FIFO scheduling. In Proceedings of the 52nd Annual Design Automation Conference, page 41. ACM, 2015. Google Scholar
  21. L. X. Zhao, H. G. Xiong, Z. Zheng, and Q. Li. Improving worst-case latency analysis for rate-constrained traffic in the time-triggered ethernet network. IEEE Communications Letters, 18(11):1927-1930, 2014. Google Scholar
  22. Luxi Zhao, Paul Pop, Qiao Li, Junyan Chen, and Huagang Xiong. Timing analysis of rate-constrained traffic in TTEthernet using network calculus. Real-Time Systems, 53(2):254-287, 2017. Google Scholar