Round Trips to First Request — TCP+TLS 1.3 vs QUIC

Round Trips to First Request — TCP+TLS 1.3 vs QUIC A sequence diagram generated by Archify. SYN SYN+ACK ACK TLS ClientHello TLS starts only after a full TCP RTT ServerHello · certificate · Finished Finished + HTTP request QUIC Initial (carries ClientHello) transport + crypto handshake in one exchange Handshake (certificate · Finished) HTTP/3 request TCP + TLS 1.3 — 2 RTT to first request QUIC — 1 RTT (0 RTT on resumption) Client · browser · Sequence participant Client browser Server · e.g. example.com · Sequence participant Server e.g. example.com Legend request return security default message