QUIC Version 1 is live on Cloudflare

On May 27, 2021, the Internet Engineering Task Force published RFC 9000, standardizing the QUIC transport protocol. This marks a significant milestone in internet engineering as it overcomes challenges faced by traditional transport protocols like TCP. QUIC is designed to be secure by default and provides features that speed up connection handshakes and mitigate performance issues on networks with loss or delays. It also supports iterative development and deployment of new features or enhancements. As of May 28, 2021, the standardized version of QUIC is available to Cloudflare customers. The company has been supporting QUIC since 2018 and has seen a steady increase in its adoption, with around 12% of internet traffic using QUIC with HTTP/3 already. To enable QUIC and HTTP/3 for domains, users can turn it on from the "Network" tab of their dashboard. Cloudflare servers listen for QUIC traffic on UDP port 443, and clients initiate connections by sending an Initial QUIC packet in a UDP datagram. The deployment of QUIC is facilitated by HTTP Alternative Services (RFC 7838), which informs TCP-based clients about the availability of HTTP/3. Web browsers will use this method to determine which protocols to use, and Cloudflare has begun rolling out changes to its Alt-Svc advertisements to include support for QUIC v1. The implementation of QUIC at Cloudflare is powered by quiche, an open-source Rust library that exposes a C API. The company has built several tools to help with development and testing, including quiche-client, which provides detailed information on QUIC connections. As the adoption of QUIC continues to grow, the IETF will focus on maintenance, operations, extensibility, and the development of QUIC version 2.