There is a resurgence of interest in Byzantine fault-tolerant (BFT) systems due to blockchains. However, leader-based BFT consensus protocols used by permissioned blockchains have limited scalability and robustness. To alleviate the leader bottleneck in BFT consensus, we introduce Stratus, a robust shared mempool protocol that decouples transaction distribution from consensus. Our idea is to have replicas disseminate transactions in a distributed manner and have the leader only propose transaction ids. Stratus uses a provably available broadcast (PAB) protocol to ensure the availability of the referenced transactions. We implemented and evaluated Stratus by integrating it with state-of-the-art BFT-based blockchain protocols and evaluated these protocols in both LAN and WAN settings. Our results show that Stratus-based protocols achieve up to 5∼20× more throughput than their native counterparts in a network with hundreds of replicas. In addition, the performance of Stratus degrades gracefully in the presence of network asynchrony, Byzantine attackers, and unbalanced workloads. Our design provides easy-to-use APIs so that other BFT systems suffering from leader bottlenecks can use Stratus.
@article{arxiv.2203.05158,
title = {Scaling Blockchain Consensus via a Robust Shared Mempool},
author = {Fangyu Gai and Jianyu Niu and Ivan Beschastnikh and Chen Feng and Sheng Wang},
journal= {arXiv preprint arXiv:2203.05158},
year = {2022}
}