CSDL Home IEEE Transactions on Dependable and Secure Computing 2009 vol.6 Issue No.04 - October-December

Subscribe

Issue No.04 - October-December (2009 vol.6)

pp: 269-281

Martin Hutle , EPFL Vienna University of Technology, Vienna

Dahlia Malkhi , Microsoft Research

Ulrich Schmid , Vienna University of Technology, Vienna

Lidong Zhou , Microsoft Research

DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/TDSC.2008.24

ABSTRACT

Aguilera et al. and Malkhi et al. presented two system models, which are weaker than all previously proposed models where the eventual leader election oracle Ω can be implemented, and thus, consensus can also be solved. The former model assumes unicast steps and at least one correct process with f outgoing eventually timely links, whereas the latter assumes broadcast steps and at least one correct process with f bidirectional but moving eventually timely links. Consequently, those models are incomparable. In this paper, we show that Ω can also be implemented in a system with at least one process with f outgoing moving eventually timely links, assuming either unicast or broadcast steps. It seems to be the weakest system model that allows to solve consensus via Ω-based algorithms known so far. We also provide matching lower bounds for the communication complexity of Ω in this model, which are based on an interesting “stabilization property” of infinite runs. Those results reveal a fairly high price to be paid for this further relaxation of synchrony properties.

INDEX TERMS

Distributed systems, failure detectors, fault-tolerant distributed consensus, system modeling, partial synchrony.

CITATION

Martin Hutle, Dahlia Malkhi, Ulrich Schmid, Lidong Zhou, "Chasing the Weakest System Model for Implementing Ω and Consensus",

*IEEE Transactions on Dependable and Secure Computing*, vol.6, no. 4, pp. 269-281, October-December 2009, doi:10.1109/TDSC.2008.24REFERENCES