QUIC.
also: HTTP/3 · HTTP3The UDP-based transport under HTTP/3: per-stream loss recovery (no TCP head-of-line blocking) and 0-RTT or 1-RTT connection setup.
the two-minute refresher
- Stack: HTTP/3 → QUIC → UDP → IP, instead of HTTP → TCP → IP.
- A lost packet only delays its own stream.
- Handshake and TLS are combined: 1-RTT, or 0-RTT on resumption, versus 2 RTT for TCP + TLS 1.3.
- Connections survive network changes (Wi-Fi to mobile) because they are not tied to the IP/port pair.