SarlBFT: Scalable Tree Communication Pattern BFT Protocol

With the increasing interest in blockchain within the business domain, there has been a growing focus on the implementation of permissioned blockchains. However, many of these blockchains rely on Byzantine Fault Tolerance (BFT) consensus algorithms that suffer from scalability limitations and restricted throughput. Furthermore, most of these protocols are primarily designed based on stable-leader, lacking in terms of fairness. Common techniques aimed at enhancing efficiency and fairness include pipelining and leader rotation. Despite these efforts, the throughput of these methods remains limited, and the protocols necessitate a sequence of consecutive three or four correct leaders to commit operations. To tackle this challenge, we propose an innovative BFT protocol based on a Tree-like Pipeline named SarlBFT. This protocol demonstrates its effectiveness in maintaining operational continuity and achieving high data processing rates, even when successive reliable leaders are not present. Additionally, supporting leader rotation enhances fairness and strengthens resistance against censorship. Our evaluation results indicate that SarlBFT reduces the expected commit latency of HotStuff by nearly 2 times in the event of failures, while concurrently increasing throughput by approximately 5 times.