EIP-2183: Increase the Clique MIN_WAIT for out-of-turn blocks

EIPS/eip-2183.md

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+---
+eip: 2183
+title: Increase the Clique MIN_WAIT for out-of-turn blocks
+author: Jardel Webb (@soc1c)
+discussions-to: https://github.com/goerli/eips-poa/issues/16
+status: Draft
+type: Standards Track
+category: Core
+created: 2019-07-09
+requires: 225
+---
+
+## Simple Summary
+
+This document proposes a patch for the Clique proof-of-authority consensus engine that could be used by Ethereum testing and development networks in the future which improves performance and stability.
+
+## Abstract
+
+Edge-cases in Clique-based networks were discovered that eventually lead the chain to halt. One of the reasons is that some clients publish out-of-turn to the network too fast. EIP-2183 addresses this and encourages clients that implement Clique to streamline their block-authoring logic based on this proposal.
+
+## Motivation
+
+The _Kotti Classic_ and _Görli_ testnets running different implementations of the _Clique_ engine got stuck multiple times due to minor issues discovered. To increase the performance and stability of Clique-based networks, a series of proposals will be published to address this.
+
+## Specification
+
+This section specifies a protocol upgrade to the Clique engine which is not relevant to consensus. No activation schedule is required.
+
+All clients that implement Clique are encouraged to use the following definition in addition to EIP-225:
+
+* **`MIN_WAIT`**: The minimum time to wait for an out-of-turn block to be published. It is suggested to set it to `BLOCK_PERIOD / 2`.
+
+There is a chance that clients don't honor this. Therefore, In case an out-of-turn block is received, an **in-turn signer should continue to publish their block** to ensure the chain always prefers in-turn blocks in any case. This strategy prevents in-turn validators from being hindered from publishing their block and potential network halting.
+
+This strategy will always ensure that an in-turn signer has a **substantial advantage** to sign and propagate versus the out-of-turn signers.
+
+## Rationale
+
+This proposal introduces a **`MIN_WAIT`** period for an out-of-turn block to be published, which is not present for Clique. This addresses the issue of out-of-turn blocks often getting pushed into the network too fast, causing a lot of short reorganizations and in some rare cases causing the network to come to a halt. By holding back out-of-turn blocks, Cliquey allows in-turn validators to seal blocks even under non-optimal network conditions, such as high network latency or validators with unsynchronized clocks.
+
+This change is not relevant to consensus. No activation schedule is required. All clients that implement Clique are encouraged to adapt the minimum-wait delay on top of EIP-225.
+
+This measure was discussed and proposed in: [goerli/testnet/#57](https://github.com/goerli/testnet/issues/57)
+
+## Copyright
+Copyright and related rights waived via [CC0](https://creativecommons.org/publicdomain/zero/1.0/).