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arXiv · 2304.07850

Trees and Turtles: Modular Abstractions for State Machine Replication Protocols

Natalie Neamtu·Haobin Ni·Robbert van Renesse
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Abstract

We present two abstractions for designing modular state machine replication (SMR) protocols: trees and turtles. A tree captures the set of possible state machine histories, while a turtle represents a subprotocol that tries to find agreement in this tree. We showcase the applicability of these abstractions by constructing crash-tolerant SMR protocols out of abstract tree turtles and providing examples of tree turtle implementations. Tree turtles can also be extended to be made Byzantine fault-tolerant (BFT). The modularity of tree turtles allows a generic approach for adding a leader for liveness. We expect that these abstractions will simplify reasoning and formal verification of SMR protocols as well as facilitate innovation in protocol designs.

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Natalie Neamtu, Haobin Ni, Robbert van Renesse. 2023-04-16. Trees and Turtles: Modular Abstractions for State Machine Replication Protocols. https://doi.org/10.1145/3578358.3592148

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