Scaling Byzantine Consensus: A Sharded and Pipelined Approach for Permissioned Blockchains

Practical Byzantine Fault Tolerance (PBFT) is a widely used consensus protocol for permissioned blockchains, offering strong consistency and fault tolerance. However, its scalability is limited by high communication overhead and sequential processing bottlenecks. In this work, we propose a novel optimization of PBFT by incorporating sharding and pipelining. Sharding partitions the network into smaller groups, enabling parallel transaction validation, while pipelining overlaps communication and execution phases to reduce idle time. We present the design and implementation of these techniques within a PBFT framework and evaluate their performance in a simulated environment. Our results demonstrate significant improvements in both throughput and latency under varying loads, showing that combining sharding and pipelining can effectively enhance PBFT’s scalability without compromising fault tolerance. For example, we achieved 1,120 transactions per second —more than 18 times the throughput of our benchmark— in a network of 128 nodes, and the performance gap between our solution and the benchmark widened as the network size increased. This approach offers a promising direction for optimizing consensus in large-scale permissioned blockchain networks.