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Epochs and Reconfiguration

Epoch​

In IOTA, an epoch is a set period, around 24 hours, during which the IOTA validator set and their stakes remain constant. This stable period allows validators to handle transactions smoothly without unexpected changes.

Epoch values are part of the transaction data on the IOTA network, but regular users don't need to worry about them. Users only need to know about epochs if they are dealing with expiring transactions, which must be completed before a specific epoch ends.

Reconfiguration​

Reconfiguration is an important process that happens at the end of each epoch to prepare the network for the next one. It includes these key steps:

1. Finalizing Transactions and Checkpoints​

The network agrees on the final set of transactions and checkpoints for the current epoch, ensuring all validators have the same information. This is the only time the network is fully synchronized, known as a synchronous moment, which is essential for consistency.

2. Distribution of Gas Rewards​

Computation gas fees are distributed to the validator staking reward pool, allowing stakers to withdraw their rewards.

3. Validator Set Change​

Any pending staking and unstaking requests are finalized and reflected in the validators' stake distribution. Any pending changes to the validator set, such as adding or removing validators, are processed. This is the only time the validator set and stake distribution can be altered.

4. Protocol Upgrade​

info

In Byzantine Fault Tolerant (BFT) f represents the number of faulty validators. 2f+1 represents the minimum number of validators needed to agree on a transaction to ensure integrity and finality, even if up to f validators are faulty.

For example, if f = 1, this means 3 validators must confirm a transaction (a supermajority) to guarantee its integrity, ensuring that even if one validator is faulty, the correct decision still stands.

If 2f+1 validators agree, the network may upgrade to a new protocol version, which includes new features, bug fixes, and updates to the Move framework libraries.

Quizzes​

Question 1/3

What is the primary purpose of an epoch in the IOTA network?