Abstract
Successfully attaining consensus in the absence of a centralized coordinator is a fundamental problem in distributed multi-agent systems. We analyze progress in the Synod consensus protocol—which does not assume a unique leader—under the assumptions of asynchronous communication and potential agent failures. We identify a set of sufficient conditions under which it is possible to guarantee that a set of agents will eventually attain consensus using Synod. First, a subset of the agents must not permanently fail or exhibit Byzantine failure until consensus is reached, and second, at least one proposal must be eventually uninterrupted by higher-numbered proposals. To formally reason about agent failures, we introduce a failure-aware actor model (FAM). Using FAM, we model the identified conditions and provide a formal proof of eventual progress in Synod. Our proof has been mechanically verified using the Athena proof assistant and, to the best of our knowledge, it is the first machine-checked proof of eventual progress in Synod.
Original language | English (US) |
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Pages (from-to) | 395-410 |
Number of pages | 16 |
Journal | Innovations in Systems and Software Engineering |
Volume | 19 |
Issue number | 4 |
DOIs | |
State | Published - Dec 2023 |
Keywords
- Athena
- Fairness
- Formal theorem proving
- Liveness
- Paxos
- Urban air mobility
ASJC Scopus subject areas
- Software