Today's mainstream network timing models for distributed computing are synchrony, partial synchrony, and asynchrony. These models are coarse-grained and often make either too strong or too weak assumptions about the network. This paper introduces a new timing model called granular synchrony that models the network as a mixture of synchronous, partially synchronous, and asynchronous communication links. The new model is not only theoretically interesting but also more representative of real-world networks. It also serves as a unifying framework where current mainstream models are its special cases. We present necessary and sufficient conditions for solving crash and Byzantine fault-tolerant consensus in granular synchrony. Interestingly, consensus among n parties can be achieved against f≥n/2 crash faults or f≥n/3 Byzantine faults without resorting to full synchrony.
@article{arxiv.2408.12853,
title = {Granular Synchrony},
author = {Neil Giridharan and Ittai Abraham and Natacha Crooks and Kartik Nayak and Ling Ren},
journal= {arXiv preprint arXiv:2408.12853},
year = {2024}
}