Delphi Digital: Solana is preparing for an Alpenglow upgrade, theoretically confirming a 100x reduction in latency.
TL;DR
Solana's Alpenglow upgrade aims to drastically reduce latency by overhauling consensus with Votor for faster voting and Rotor for efficient block propagation, targeting sub-second finality and a 100x speed improvement.
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On January 4th, Delphi Digital published an article on the X platform stating that Solana is preparing for a major upgrade to Alpenglow. This upgrade is a complete overhaul of the consensus mechanism, aiming to achieve sub-second finality by replacing Tower BFT and Proof-of-History (PoH). Alpenglow introduces two new protocol components: Votor and Rotor.
Votor replaces Tower BFT's incremental voting rounds with a lightweight voting aggregation model. Validators can aggregate votes off-chain before committing final confirmation, allowing blocks to be finalized within 1 to 2 confirmation rounds. This improvement reduces theoretical finality latency to 100 to 150 milliseconds, approximately 100 times faster than the initial 12.8 seconds. Votor achieves final confirmation through two parallel paths: fast confirmation is triggered and takes effect immediately when the proposed block receives more than 80% of the total staking weight in the first round; slow confirmation is triggered if the first round support is between 60% and 80%, requiring a second round of voting to exceed 60% for final confirmation.
Rotor refactors Solana's block propagation layer. The original Turbine propagation network relied on multi-hop relays with variable latency, while Rotor introduces staking-weighted relay paths, prioritizing bandwidth efficiency. High-staking, bandwidth-reliable validators will become the core relay points. Simulation data shows that, under typical bandwidth conditions, block propagation can be completed in as little as 18 milliseconds. This upgrade is expected to be rolled out gradually, with an initial launch anticipated between early and mid-2026.