According to BlockBeats, Solana is preparing for a significant upgrade named Alpenglow, which aims to overhaul its consensus mechanism. This upgrade will replace Tower BFT and Proof of History (PoH) to achieve sub-second finality. Alpenglow introduces two new protocol components: Votor and Rotor.
Votor replaces the incremental voting rounds of Tower BFT with a lightweight vote aggregation model. Validators can aggregate votes off-chain before submitting final confirmations, allowing blocks to achieve finality within one to two confirmation rounds. This improvement reduces theoretical finality latency to 100 to 150 milliseconds, a significant decrease from the original 12.8 seconds. Votor achieves final confirmation through two parallel paths: a fast confirmation is triggered and immediately effective when a proposed block receives over 80% total stake weight support in the first round; if the first-round support is between 60% and 80%, a slow confirmation is triggered, requiring a second-round vote exceeding 60% for final confirmation.
Rotor restructures Solana's block propagation layer. The existing Turbine propagation network relies on multi-hop relays with variable delays, while Rotor introduces a stake-weighted relay path prioritizing bandwidth efficiency. Validators with high stakes and reliable bandwidth will become core relay points. Simulations indicate that under typical bandwidth conditions, block propagation can be completed in as little as 18 milliseconds. This upgrade is expected to be gradually implemented, with an initial rollout anticipated between early and mid-2026.
