ABBA: Advance Block Body Agreement for Scaling Blockchain Networks

Scalability is one of the main issues of blockchains that limits its applications. Blockchain throughput (i.e., transactions per second) is constrained by its block size, and block generation rate is restricted by consensus time and the network size. Despite many scaling approaches available, most of them are either not applicable to existing blockchains, or oblivious to blockchain applications. We propose a novel blockchain network scalability mechanism, Advance Block Body Agreement (ABBA), that uses pre-agreement on an upcoming block body to reduce consensus time without changing the consensus algorithm itself. A block size of a blockchain is limited since a large block size causes higher consensus time and unnecessary transient forks, resulting in an unstable network. By reducing consensus time, ABBA allows increasing a blockchain's block size that leads to a higher throughput. ABBA also reduces transient forks in blockchain networks reducing unnecessary network overhead. ABBA can be used with any consensus protocol without changing consensus or its application layer. It can also be used with other existing scalability approaches complementarily. We have built an efficient blockchain network simulator and conducted extensive evaluations under various network conditions. The results show that an ABBA-enabled blockchain network has a significantly higher throughput and lower transient forks than an original base blockchain network.