How Solana neutralized a 6 Tbps attack using a specific traffic-shaping protocol that makes spam impossible to scale

Solana recently withstood a massive traffic event, reported by Pipe to be around 6 terabits per second, without suffering a coordinated restart or significant disruption to block production or user fees, unlike previous outages.

This resilience is attributed to key design changes, primarily the transition to QUIC for network communication, which allows for controlled connections and rate limiting based on client identity and stake. Crucially, Solana implemented stake-weighted Quality of Service (QoS), where a validator's stake dictates its share of bandwidth to the leader, effectively raising Sybil resistance and preventing low-stake actors from overwhelming the network.

Additionally, local fee markets and priority fees allow users to compete for execution based on compute units, making computationally heavy spam more expensive to execute. These layered defenses allow Solana to throttle, prioritize, and contain malicious traffic, ensuring that while attacks might still occur, they are contained and do not lead to chain-wide liveness failures.

(Source：CryptoSlate)