What is the role of consensus in a proof-of-authority blockchain network?

@joelle 

In a proof-of-authority (PoA) blockchain network, the role of consensus is to reach an agreement a**** the network participants regarding the validity and order of transactions added to the blockchain. However, unlike other consensus mechanisms such as proof-of-work (PoW) or proof-of-stake (PoS), PoA networks do not rely on decentralized mining or staking to achieve consensus.

In a PoA network, a predefined set of authorities or validators, often referred to as "masternodes," are responsible for creating blocks and validating transactions. These authorities are trusted entities or individuals who have been granted the permission to participate in the network based on their reputation, identity, or stake in the system.

When a transaction is submitted for inclusion in the blockchain, the network relies on the consensus algorithm to ensure that at least a predetermined number of authorities agree on its validity. This agreement is reached through a series of pre-established rules that define the conditions for verifying and accepting transactions.

Consensus in a PoA network usually involves a mechanism where each authority takes turns proposing and validating blocks. Once an authority creates a new block, it must distribute that block to all other authorities for validation. If a predetermined number of authorities agree that the block and its transactions are valid, it is added to the blockchain, and the consensus is achieved.

As a result, the role of consensus in a PoA blockchain network is to maintain agreement and consistency a**** the trusted authorities, ensuring that only valid transactions are added to the blockchain and eliminating the need for resource-intensive mining competition or stake-based voting mechanisms.