Consensus is the primary function of the Blockchain technology as it makes it more transparent and secure. On a Blockchain network, all the nodes participate to establish consensus on every type of data to be stored on the blockchain network. While establishing consensus, every node on the network validates that the ongoing transaction is valid from both the sending and receiving ends.
Delegated Proof of Stake is a consensus mechanism that enables us to establish consensus within the network in a secure and democratic way.
‘Democratic way’ in a sense that it enables the network users/community to select the best delegate through voting system and get their transactions validated by their own chosen delegate. In DPoS, all the users on the network have to stake some amount of assets (coins) first, to become able to cast votes for the candidates: willing to take charge as a delegate. They usually get inspired by the campaigns that the willing candidates run in order to win the elections. The more votes they will get, the more they have the chances to win and start earning through transaction validation and block generation.
The primary function that the delegates serve with, is the validation of the transactions that they get from the pool of invalidated transactions — called Transaction Pool, broadcast them on the network to let other network peers/nodes/users update about it, create a block containing these validated transactions, and append it with the existing chain. On performing these functions, the delegates get incentivized with the crypto coins launched by the network on which they are.
On the other hand, the stakeholders stake their asset (coins) for a specified period and cast votes for the candidates who want to become delegates. The network specify a limit for the stakeholders about the number of votes he/she must have to cast within a specific period. On successfully meeting the parameters/limits, the stakeholders get incentivized with the coin-based reward. Not only this, the stakeholders also get reward from the delegates to whom they cast votes.
This makes DPoS a very convincing and appealing consensus mechanism to adopt for different systems.