Solana Unveils Alpenglow Upgrade to Shave Finality to Sub-Second
Solana is gearing up for its Alpenglow upgrade, which promises to significantly improve the network's finality through a major overhaul of its consensus protocol. The current Tower BFT and Proof of History protocols are being replaced with two new components: Votor and Rotor.
Votor will introduce a lightweight vote aggregation model that allows validators to aggregate votes off-chain before committing finality, reducing theoretical finality from 12.8 seconds to 100-150 milliseconds. This is achieved through two concurrent finalization paths, Fast Finalization and Slow Finalization, which trigger when a proposed block gains 80% or more of total stake approval in the first round, or when the first round reaches 60% to 80%, respectively.
Meanwhile, Rotor will redesign the block propagation layer by introducing stake-weighted relay paths that prioritize bandwidth-efficient propagation. High-stakes validators with reliable bandwidth will become key relay points, replacing the original Turbine gossip network's multihop relays with variable latency.
The upgrade is expected to address stability and validator performance concerns, which have drawn criticism despite Solana's speed and low fees. With its on-chain trading volume reaching $1.6 trillion in 2025, surpassing all exchanges except Binance, the success of Alpenglow will be closely watched by the crypto community.