[BIP Proposal] Stale Tip Relay

An incremental approach is proposed for protocol changes, with the recommendation to initially relay only stale headers instead of full block data. This method is considered effective in providing most of the desired benefits while minimizing potential disruptions or negative impacts on mining incentives. Relaying stale headers allows for increased observability of stale blocks without immediately affecting the underlying incentive structure that governs miner behavior.

The transmission of stale headers is said to offer a significant advantage: it increases the expected revenue for miners who temporarily mine on top of a block, even if they do not ultimately win the race to extend the blockchain. At the same time, this update slightly accelerates convergence within the network, as honest miners whose chains are overtaken can more quickly switch to the dominant chain. However, any change to how such information is relayed inevitably alters the incentive landscape, making it necessary to analyze whether these changes promote greater network convergence or divergence, and to what extent these effects are meaningful.

It is argued that performing a detailed incentive analysis for the simple act of relaying stale headers might be unnecessary, since headers alone sufficiently enhance the transparency regarding the presence of stale blocks. Pre-relaying headers does not introduce the same incentive complications as relaying full block content, which would include additional details such as pool attribution from the coinbase transaction and validation status. Therefore, the suggestion is to first specify and implement the relay of stale headers. Only after evaluating the results of this limited change should further consideration be given to relaying additional block information, weighing its potential impact on mining incentives.