Re: Benjamin Kaduk's Discuss on draft-ietf-quic-transport-33: (with DISCUSS and COMMENT)

[Martin Thomson <[e-mail]>]

Excision performed in the service of brevity.
On Thu, Jan 7, 2021, at 17:54, Benjamin Kaduk wrote:
> Yes.  Do we have any reason to believe that non-standards-track versions
> will or will not intend to coexist with v1?  I, at least, do not have any
> data on that question either way.  I think this relates to my (3) above --
> are we assuming that the problem of downgrade protection only becomes
> relevant when there is specifically an IETF v2?

We have no information, but that indicates more that we have time to work on a solution.

> I agree that it's not necessarily limited to QUIC, though even having
> something that only works within the QUIC ecosystem would be better than
> nothing.  It would be surprising to define a protocol with verisons and a
> Version Negotiation packet but end up with technical flaws that prevent
> that packet from working properly, though.

I am confident that we have enough of an escape valve that we will be able to define new versions securely.  As is the working group (who I am certain will speak up if they disagree).

> I think it would be fruitful to try to drill a little more into
> what assumptions we are making when we say (okay, I'm synthesizing a bit,
> but I believe this is the sentiment) that "it is safe to defer availability
> of this mechanism until a future version of the protocol exists".

If only we hadn't already discussed this at length.

> (I recognize that answering that last one may end up being nearly as hard to
> answer as actually solving the problem.)

I think that we know the answer in the general sense, just not in the specific sense of being able to define the bits and manage operational concerns and other protocol design constraints.

> My main goal here is to have some reasonable level of confidence that we
> are not putting ourselves in a position that will be hard or impossible to
> get out of in the future.  Depending on what assumptions we are making, it
> may be very easy or somewhat less easy to achieve such confidence, but
> deferring entirely to future versions of the protocol without information
> on how or when such version(s) will appear leaves me without much
> confidence on that front.

The working group reached that confidence.  I don't know how much effort I'm able to devote now to helping you reach that state.  Perhaps other participants would like to offer their help now.