Managing Consensus in Distributed Transaction Systems

Blockchain systems are only the latest beneficiary of consensus protocols, which first appeared to answer the agreement problem. Although agreement (or consensus) plays a pivotal role in enabling distributed transaction systems, it also poses several key challenges, especially in terms of high computation/communication costs. Although different consensus protocols may all allow participants to (eventually) agree upon a shared value, the underlying variations in implementation may have drastic impacts on the effectiveness and scalability of the overall system. In this chapter, we briefly summarize several key developments that enabled real-world usage of fault-tolerant consensus and discuss more recent developments, especially within the context of distributed ledger systems and blockchain.