Adaptive Switching Between Leader-Based and Leaderless BFT Protocols

2026-09-25

AI Summary

This study addresses the limitations of static BFT protocols in handling dynamic networks and leader-adaptive attacks by proposing BFTide, a novel architectural framework. Its core innovation lies in embedding protocol-switching logic directly into the consensus execution process. By integrating reinforcement learning strategies with runtime metric monitoring, BFTide enables intelligent and rapid switching between leader-based and leaderless protocols. Notably, it achieves safe, low-overhead migration to an asynchronous leaderless mode without requiring additional consensus rounds. Experimental evaluations demonstrate that the proposed system significantly reduces transaction latency while maintaining high throughput under adverse network conditions, introducing only a 10%–21% median latency overhead during idle states.

Abstract

Byzantine fault-tolerant (BFT) protocols are known for providing operational consistency and resilience in distributed systems. However, evolving network conditions, often driven by the network's inherent dynamism or adversarial influence, make it suboptimal to rely on a static protocol at all times. Existing BFT protocol adaptation solutions switch only among leader-based protocols and coordinate each switch through a separate consensus round, leaving them ineffective at handling severe asynchrony or situations in which an adaptive adversary targets the network's leader. We propose BFTide, a protocol adaptation architecture that enables a BFT system to intelligently and swiftly switch to a suitable protocol as network conditions shift. BFTide integrates a novel protocol switching layer that embeds protocol transition logic into the ongoing BFT operation, enabling safe and low-overhead transitions between partially synchronous leader-based protocols and asynchronous leaderless protocols. It further incorporates an offline-trained reinforcement learning policy that allows nodes to propose protocols at runtime based on observed system metrics. Experimental results show that BFTide reduces transaction latency under adverse network conditions compared with static BFT protocols and the state-of-the-art BFT protocol adaptation scheme BFTBrain (NSDI'25), while maintaining comparable throughput. The switching layer adds a modest 10-21% overhead to median latency when idle and requires no separate consensus round per switch.

Problem

• Byzantine fault tolerance
• protocol switching
• leader-based protocols
• leaderless protocols
• adaptive adversary

Innovation

• Byzantine Fault Tolerance
• Protocol Switching
• Reinforcement Learning
• Leaderless BFT
• Adaptive Systems