FastChain: Scaling Blockchain System with Informed Neighbor Selection

The main advantage of the Bitcoin-style blockchain systems is immutability of data and decentralized authority. Despite its success, Bitcoin suffers from scalability issues. The potential of the blockchain technology cannot be fully realized unless it is made more scalable. We extend previous analysis on a fundamental trade-off between the throughput and forking rate of the blockchain system. We further propose FastChain to increase the throughput of the blockchain system by reducing the block propagation time. FastChain adopts bandwidth-informed neighbor selection. Miners disconnect from bandwidth-limited neighbors and favor the nodes with higher bandwidth. We build a Blockchain Dynamics Simulator (BDSim) to evaluate the performance of FastChain. FastChain improves the throughput by 20%~40% in the normal operations.