On Tue, Oct 18, 2022, at 18:39, Maxime Piraux wrote: > To me, when reading RFC9000, addresses provided in preferred_address are > expected to be used shortly after the handshake. So a client that > prefers one address family over the other can use its "best server > preferred address" and migrate across address families indeed.
So I guess the question can be framed differently: Why would a client choose to defer use of this transport parameter? And how would the client decide that when the transport parameter should be used? To your other points, the expectation is that a preferred address is acted upon immediately after the connection is complete. If the following is unclear, we can improve it if and when we revise RFC 9000, but I don't see this as implying unlimited license to use the address: > QUIC allows servers to accept connections on one IP address and attempt to > transfer these connections to a more preferred address shortly after the > handshake. -- https://quicwg.org/base-drafts/rfc9000.html#section-9.6-1
