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arXiv · 1410.7256

Interactive Consistency in practical, mostly-asynchronous systems

Panos Diamantopoulos·Stathis Maneas·Christos Patsonakis·Nikos Chondros·Mema Roussopoulos
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Abstract

Interactive consistency is the problem in which n nodes, where up to t may be byzantine, each with its own private value, run an algorithm that allows all non-faulty nodes to infer the values of each other node. This problem is relevant to critical applications that rely on the combination of the opinions of multiple peers to provide a service. Examples include monitoring a content source to prevent equivocation or to track variability in the content provided, and resolving divergent state amongst the nodes of a distributed system. Previous works assume a fully synchronous system, where one can make strong assumptions such as negligible message delivery delays and/or detection of absent messages. However, practical, real-world systems are mostly asynchronous, i.e., they exhibit only some periods of synchrony during which message delivery is timely, thus requiring a different approach. In this paper, we present a thorough study on practical interactive consistency. We leverage the vast prior work on broadcast and byzantine consensus algorithms to design, implement and evaluate a set of algorithms, with varying timing assumptions and message complexity, that can be used to achieve interactive consistency in real-world distributed systems. We provide a complete, open-source implementation of each proposed interactive consistency algorithm by building a multi-layered stack of protocols that include several broadcast protocols, as well as a binary and a multi-valued consensus protocol. Most of these protocols have never been implemented and evaluated in a real system before. We analyze the performance of our suite of algorithms experimentally by engaging in both single instance and multiple parallel instances of each alternative.

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Panos Diamantopoulos, Stathis Maneas, Christos Patsonakis, Nikos Chondros, Mema Roussopoulos. 2014-10-27. Interactive Consistency in practical, mostly-asynchronous systems. https://arxiv.org/abs/1410.7256

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