Solana’s geographic speed plan trusts validator locations the network cannot verify

Solana Proposes New Validator Scheduling to Reduce Handover Delays

Introduction

Roger Wattenhofer and Quentin Kniep propose speeding Solana's block production by scheduling nearby validators consecutively. Their plan relies on self-reported locations, bringing an unverifiable physical input into the order of block producers.

Proposed System

The proposed system uses a 10% stake floor to define how widely a validator's neighborhood must extend to reach enough stake. A densely populated location gets a smaller radius; a sparse one needs a larger radius. The floor covers active stake with valid reported locations.

Simulation Results

The authors' simulation cuts the mean handover delay between honest validators from 36.2 milliseconds to 17.0 milliseconds without giving any validator more leader windows. Reordering also changes the continuity of control: three-window groups can combine into longer consecutive stretches.

Security Trade-off

The security trade-off appears in the same simulation. An adversary holding 5% of total stake and sitting in Sydney, with no other validator in Oceania, can fill bins alone. The authors describe this isolated placement as close to a worst case because the attacker can continue its control across the boundary.

Conclusion

The proposed validator scheduling system has the potential to reduce handover delays and improve decentralization. However, the system's reliance on self-reported locations and the 10% stake floor may introduce security risks. Further evaluation and testing are needed to determine the effectiveness and feasibility of this system.