Proposal to Set the Number of Consecutive Blocks per Validator to 4 After the Bohr Upgrade

Summary

This proposal seeks to configure the number of consecutive blocks each validator can produce on the BNB Smart Chain (BSC) after the Bohr upgrade. Following the guidelines set out in BEP-341, we recommend setting this value to 4 to achieve an optimal balance between network performance and security.

##Justification With the upcoming Bohr upgrade, BSC will introduce the ability for validators to produce consecutive blocks. This change aims to enhance the network's processing performance. BEP-341 defines a valid range for the number of consecutive blocks (n) from 1 to 9, excluding 2. However, empirical testing indicates that the performance benefits do not scale proportionally beyond n=5.

As shown in the graph, it is evident that continuous block production cannot double the TPS. There is no benefit when n<3, and increasing n beyond 5 does not proportionally increase the benefits. Therefore, a value within the range [3, 5] is suitable for n; when n=4, r=50%.

MEV Consideration

To prevent increased MEV (Maximal Extractable Value) extraction during consecutive block production, BEP-341 introduces a linear increase in the transaction fee split to the SystemRewardContract based on the block number, capped by the systemRewardAntiMEVRatio. This mechanism encourages validators to promptly package transactions, reducing the risk of MEV abuse and promoting fairness within the network. Initially, the SystemRewardContract is set to 0 to maintain the current economic incentives for validators. In the BSC ecosystem, most validators have already integrated Proposal Builder Separation (PBS), where builders compete on a per-block basis. As a result, strategies attempting to place more transactions in blocks produced later in a sequence will fail because builders who immediately package transactions can propose higher-fee batches.

If a significant delay in transaction packaging and an increase in MEV extraction occur, the community can propose changes to the SystemRewardContract value through governance to address the issue.

Performance Improvements: Based on actual test results:

• n = 3: Yields a maximum performance improvement of 23%.
• n = 4: Yields a maximum performance improvement of 36%.
• n = 5: Yields a maximum performance improvement of 38%.

While a higher n can lead to improved performance, it also increases the duration a single validator controls the transaction packaging process, potentially increasing the likelihood of Maximal Extractable Value (MEV) extraction. Therefore, to maintain a balance between performance gains and network security, setting n to 4 is proposed as the most balanced choice.

Proposal

We propose setting the number of consecutive blocks that each validator can produce to 4 post the Bohr upgrade. This setting is expected to deliver significant performance improvements while minimizing the potential risks associated with longer validator control periods.

Voting Options:

• Yes: Approve setting the number of consecutive blocks per validator to 4.
• No: Do not approve setting the number of consecutive blocks per validator to 4.
• Abstain: No opinion on the matter.

Additional Information

For more details, please refer to the BEP-341 documentation.