Semisynchrony and real time

Extended abstract
  • Stephen Ponzio
  • Ray Strong
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 647)


This paper represents the confluence of several streams of resarch on the real time complexity of distributed algorithms. The primary focus of our study is on two models and two problems: the timed automata model of Attiya and Lynch and the (“latency”) model of approximately synchronized clocks studied by Strong et. al., and the problems of consensus and atomic broadcast. We compare these models and problems, producing new results and significant improvements of previously known bounds. In particular, we are able to significantly improve the upper bound of Strong, Dolev, and Cristian on latency for Byzantine failures, giving an algorithm that is much simpler with vastly easier analysis. For this problem, we also improve the best known lower bound on latency. We also provide certain reductions between problems and models and provide preliminary answers to some new questions in the timed automata model.


Clock Synchronization Correct Clock Broadcast Algorithm Message Delay Correct Processor 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. [ADKM92]
    Y. Amir, D. Dolev, S. Kramer and D. Malki. Total ordering of messages in broadcast domains. Manuscript.Google Scholar
  2. [ADLS90]
    H. Attiya, C. Dwork, N. Lynch, and L. Stockmeyer. Bounds on the time to reach agreement in the presence of timing uncertainty. MIT/LCS/TM-435, November. 1990. Also: STOC 1991.Google Scholar
  3. [AL89]
    H. Attiya and N. A. Lynch. Time bounds for real-time process control in the presence of timing uncertainty. Proc. 10th IEEE Real-Time Systems Symposium, 1989, pp. 268–284. Also: MIT/LCS/TM-403, July 1989.Google Scholar
  4. [BJ87]
    K. Birman and T. Joseph. Reliable communication in the presence of failures. ACM TOCS, Vol. 5, No. 1 (February 1987), pp. 47–76.Google Scholar
  5. [BGT90]
    N. Budhiraja, A. Gopal and S. Toueg. Early-stopping distributed bidding with applications. Proc. 4th Int'l. WDAG 1990.Google Scholar
  6. [CASD86]
    F. Cristian, H. Aghili, R. Strong and D. Dolev. Atomic broadcast: from simple message diffusion to Byzantine agreement. Proc. 15th Int. Conf. on Fault Tolerant Computing, 1985, pp. 1–7. Also: IBM Research Report RJ5244, revised October 1989.Google Scholar
  7. [CM84]
    J. M. Chang and N. Maxemchuck. Reliable broadcast protocols. ACM TOCS, Vol. 2, No. 3 (August 1984), pp. 251–273.Google Scholar
  8. [CD86]
    B. A. Coan and C. Dwork. Simultaneity is harder than agreement. Information and Computation Vol. 91, No. 2, 1991.Google Scholar
  9. [DDS87]
    D. Dolev, C. Dwork and L. Stockmeyer. On the minimal synchronism needed for distributed consensus. JACM, Vol. 34, No. 1 (1987), pp. 77–97.CrossRefGoogle Scholar
  10. [DHS86]
    D. Dolev, J. Y. Halpern and R. Strong. On the possibility and impossibility of achieving clock synchronization. JCSS, Vol. 32, No. 2, 1986, pp. 230–250.Google Scholar
  11. [DHSS89]
    D. Dolev, J. Halpern, R. Stong and B. Simons. Dynamic fault-tolerant clock synchronization. IBM Research Report RJ 6722, March 1989. Also: Faulttolerant clock synchronization. Proc. 3rd ACM PODC 1984, pp. 89–102.Google Scholar
  12. [DS83]
    D. Dolev and H. R. Strong. Authenticated algorithms for Byzantine agreement. SIAM J. Computing, Vol. 12, No. 3 (November 1983), pp. 656–666.Google Scholar
  13. [DLS88]
    C. Dwork, N. Lynch, and L. Stockmeyer. Consensus in the presence of partial synchrony. JACM, Vol. 35 (1988), pp. 288–323.CrossRefGoogle Scholar
  14. [DM86]
    C. Dwork and Y. Moses. Knowledge and common knowledge in Byzantine environments I: crash failures. Information and Computation, Vol. 88, No. 2 (1990), pp. 156–186.Google Scholar
  15. [DS91]
    C. Dwork and L. Stockmeyer. Bounds on the time to reach agreement as a function of message delay. IBM Research Report RJ8181, June 1991.Google Scholar
  16. [FL82]
    M. Fischer and N. Lynch. A lower bound for the time to assure interactive consistency. IPL, Vol. 14, No. 4 (June 1982), pp. 183–186.Google Scholar
  17. [FLP85]
    M. Fischer, N. Lynch and M. Paterson. Impossibility of distributed consensus with one faulty process. JACM, Vol. 32, No. 2 (1985), pp. 374–382.CrossRefGoogle Scholar
  18. [GSTC90]
    A. Gopal, R. Strong, S. Toueg and F. Cristian. Early-delivery atomic broadcast. Proc. 9th ACM PODC, 1990, pp. 297–309.Google Scholar
  19. [HK89]
    A. Herzberg and S. Kutten. Efficient Detection of Message Forwarding Faults. Proc. 8th ACM PODC, 1989, pp. 339–353.Google Scholar
  20. [LM85]
    L. Lamport and P. M. Melliar-Smith. Synchronizing clocks in the presence of faults. JACM, Vol. 32, No. 1 (January 1985), pp. 52–78.Google Scholar
  21. [LSP82]
    L. Lamport, R. Shostak and M. Pease. The Byzantine generals problem. ACM TOPLAS, Vol. 4, No. 3 (1982), pp. 382–401.Google Scholar
  22. [LL84]
    J. Lundelius and N. Lynch. An upper and lower bound for clock synchronization. Information and Control, Vol. 62, Nos. 2/3 (1984), pp. 190–204.Google Scholar
  23. [LL88]
    J. L. Welch and N. Lynch. A new fault-tolerant algorithm for clock synchronization. Information and Computation, Vol. 77, No. 1, (1988), pp. 1–36.Google Scholar
  24. [MMA90]
    P. M. Melliar-Smith, L. Moser and V. Agrawala. Broadcast protocols for distributed systems. IEEE Trans. on Parallel and Dist. Systems, Vol. 1, No. 1 (January 1990), pp. 17–25.Google Scholar
  25. [MMA91]
    L. Moser, P. M. Melliar-Smith and V. Agrawala. Asynchronous faulttolerant total ordering algorithms. Manuscript.Google Scholar
  26. [M85]
    M. Merritt. Notes on the Dolev-Strong lower bound for Byzantine agreement. Unpublished manuscript, 1985.Google Scholar
  27. [MMT90]
    M. Merritt, F. Modugno and M. Tuttle. Time constrained automata. Unpublished manuscript, August 1990.Google Scholar
  28. [P91]
    S. Ponzio. Consensus in the presence of timing uncertainty: omission and Byzantine failures. Proc. 10th ACM PODC, 1991, pp. 125–138. Also: MIT SM Thesis, June 1991. MIT/LCS/TR-518, October 1991.Google Scholar
  29. [ST87]
    T. K. Srikanth and S. Toueg. Optimal clock synchronization. JACM, Vol. 34, No. 3, July 1987, pp. 626–645.Google Scholar
  30. [SDC90]
    R. Strong, D. Dolev and F. Cristian. New latency bounds for atomic broadcast. Proc. 11th IEEE Real-Time Systems Symposium, 1990.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1992

Authors and Affiliations

  • Stephen Ponzio
    • 1
  • Ray Strong
    • 2
  1. 1.MIT Laboratory for Computer ScienceCambridge
  2. 2.IBM Almaden Research CenterSan Jose

Personalised recommendations