FastJett: asynchronous BFT protocol for variable bandwidth system

In distributed systems, there exists a bottleneck in asynchronous BFT protocol: the broadcast primitive, which occupies a large amount of bandwidth resources, will drag down the nodes with poor bandwidth and slow down the system to reach consensus. In this paper, we propose to decouple the broadcast phase of BFT protocol into consensus phase and message downloading phase. The consensus phase consumes less bandwidth, while the message downloading phase requires more bandwidth. Nodes with limited bandwidth only need to participate in the consensus phase, which will not slow down the overall process. We design PAVID-M protocol to realize the above decoupling, and combine it with multi-value validated Byzantine agreement (MVBA) protocol to build a complete asynchronous BFT protocol system. Experiments show that compared with HoneyBadgerBFT protocol, our scheme can reduce the delay by 43%, which significantly improves the performance of asynchronous BFT in bandwidth-constrained environments.