[oefrha]

> It's never just one round-trip

That’s not true. TLS 1.3 0-RTT cuts down on handshake roundtrips, taking one roundtrip to establish the TCP connection before data can be sent; and HTTP/3 (QUIC) with 0-RTT actually makes it zero roundtrip, HTTP request is sent directly and response is received in one roundtrip.

[littlestymaar]

Thanks for pointing that out, it looks that my knowledge was a bit outdated.

It looks like the 0-RTT thing only work for connection resumption so it will only work if the user has already visited the site before.

Still, even without it, TIL that since TLS1.3, there's only a single round-trip and not two in the TLS handshake.