# DRAFT: What is an epoch, view/round, and version?

**URL:** <https://radixtalk.com/t/draft-what-is-an-epoch-view-round-and-version/224>\
**Category:** Questions / Help\
**Tags:** todo\
**Created:** [10 January 2022 10:32 UTC](https://radixtalk.com/t/draft-what-is-an-epoch-view-round-and-version/224 "2022-01-10T10:32:35Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Stuart](https://radixtalk.com/letter_avatar_proxy/v4/letter/s/cab0a1/32.png) [@Stuart](https://radixtalk.com/u/Stuart)\
**Post date:** [10 January 2022 10:32 UTC](https://radixtalk.com/t/draft-what-is-an-epoch-view-round-and-version/224/1 "2022-01-10T10:32:35Z")

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### Epoch

An **epoch** is a period of time during which a fixed set of validators performs consensus. The Radix protocol selects the set of Top 100 validators at the start of each epoch depending how much stake has been delegated to each.

Each epoch consists of 10,000 rounds (also known as views) and the length of time of the epoch is determined by the rate at which these rounds can be produced by the validator nodes on the network.

- [Radix Learn: What is an epoch?](https://learn.radixdlt.com/article/whats-an-epoch)
- [Radix Learn: How long is an epoch?](https://learn.radixdlt.com/article/how-long-is-an-epoch-on-radix)

### Round / View

The terms **round** and **view** are used interchangeably and consist of 1 or more _state changes_ that are written to the ledger. These state changes are called transactions and may consist of internal system transactions (eg. record how many proposals a validator has completed/missed) as well as user generated transaction (eg. transfer XRD, stake/unstake, create a token).

- [Radix Learn: What are rounds?](https://learn.radixdlt.com/article/what-are-rounds-and-what-does-rounds-per-second-mean)
- [Radix Learn: What is a transaction?](https://learn.radixdlt.com/article/what-is-a-transaction-in-crypto)

### Version

TODO: A monotonically increasing number

### Timestamp:

TODO: The transaction timestamp is the median of all timestamps provided by the validators when they verified a transaction (proof?). This means that it cannot be absolutely guaranteed that the timestamp always increases for each view (unlike the version which is guaranteed to increase with every round).

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<div class="post-metadata">

**Author:** ![Mattia](https://radixtalk.com/user_avatar/radixtalk.com/mattia/32/64_2.png) [@Mattia](https://radixtalk.com/u/Mattia)\
**Post date:** [12 June 2022 17:13 UTC](https://radixtalk.com/t/draft-what-is-an-epoch-view-round-and-version/224/2 "2022-06-12T17:13:50Z")

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