De LA FAQ
Polkadot is designed to encourage active participation in Polkadot by holders of DOTs (DOTs are explained in the “DOTs” section). Active participation in this context involves a holder of DOTs performing one or more of the following roles within Polkadot:
* **Validators:** These participants will play a crucial role in adding new blocks to the Relay Chain and, by extension to all parachains, such that parties can complete cross-chain transactions via the Relay Chain. Validators perform two functions. First, verifying the information contained in an assigned set of parachain blocks is valid (such as the identities of the transacting parties and the subject matter of the contract). Their second role is to participate in the consensus mechanism to produce the Relay Chain blocks based on validity statements from other validators. Any instances of non-compliance with the consensus algorithms result in punishment by removal of some or all of the validator’s staked DOTs, thereby discouraging bad actors. Good performance, however, will be rewarded, with validators receiving transaction fees in the form of DOTs in exchange for their activities.
* **Nominators:** these participants may nominate validators to carry out validation work on their behalf by contributing to the security bond of their nominated validators. It is anticipated that a significant portion of DOTs in existence at any particular point in time are likely to be bonded to validators for the purpose staking. Bonding DOTs to a validator requires nominators to perform due diligence and constant analysis in order to select the validators which are the most likely to behave according to Polkadot’s rules. Nominators receive a pro-rata increase or reduction in their DOT holding according to the growth or depletion of the security bond to which their DOTs were contributed.
* **Collators:** These participants will sit atop parachains and provide proofs to validators based on transactions from parachains. Collators maintain parachains by aggregating parachain transactions into parachain blocks and producing state transition proofs for validators based on those blocks. They also monitor the network and prove bad behaviour to validators. Collators maintain a “full-node” for a particular parachain; meaning they retain all necessary information to be able to author new blocks and execute transactions in much the same way as miners do on current PoW blockchains. Under normal circumstances, they will collate and execute transactions to create an unsealed block and provide it, together with a zero-knowledge proof, to one or more validators responsible for proposing a parachain block.
* **Fishermen:** these participants are not engaged in the process of validating transactions in the same way as validators or nominators, but rather they deter bad actors by monitoring activity across the platform to determine whether any other participants have acted in breach of the rules. Fisherman will be required to provide significantly fewer DOTs by way of a security bond but can receive proportionately larger DOT rewards (in comparison to rewards received by validators and nominators) in proportion to the size of their security bond.