I ve been experimenting with USTP-Secure, a reliable UDP transport I ve been building. The latest version adds: Optional congestion control Retry tokens to reduce amplification risk Optional cleartext + HMAC mode (integrity without encryption) Authenticated ACK/NACK packets One design choice I m still thinking about is congestion control for an intentionally unordered reliable transport. Unlike TCP, USTPS doesn t enforce ordered delivery at the transport layer. Missing packets can be retransmitted selectively while newer packets continue flowing. I m curious how others would approach congestion control for this kind of transport, and whether there are existing designs I should study beyond QUIC, RTP/SRT, and similar protocols. Project: https://github.com/x1colegal/USTP-Secure