Re: [DNSOP] Second Working Group Last Call for draft-ietf-dnsop-extended-error

[Eric Orth <[e-mail]>]

On Fri, Oct 25, 2019 at 9:29 AM Petr Špaček <[e-mail]> wrote:

> Would it be possible to get some time allocation of your UX design folks,
> before we set the protocol in stone?
>

Not likely, unfortunately.  Downside of not having specific plans yet.
Makes it difficult to allocate UX experts.

- Is the current version with "no categorization" okay?
> - Will it be okay in future if dnsop starts adding new codes?
> - Or should we add some inherent categorization into the protocol to make
> it future-proof?
> - If a categorization is needed, what form is best for UX? (please
> suggest!)
>

Speaking for myself from a non-UX perspective (and I am not a UX expert),
forward compatibility of error codes is a common pitfall in many similar
systems.  Once error receivers start relying on specific error codes to
produce specific essential behavior, expandability often gets locked out
because you can't replace those codes with new ones that receivers might
not immediately recognize.  And having a receiver only know "unknown" error
is usually pretty bad.  Attempts to solve these issues usually involve
stuff like categorization, user-visible messages, and multiple ordered
errors, but my anecdotal experience is that it's pretty rare for such
mitigations to be fully supported by all sides to the level where it
actually helps and expandability still ends up limited.

But specifically to EDE, I think the general circumstances make us fine
without taking any specific steps to mitigate forward compatibility.  It's
mostly been designed just for "supplemental" signalling.  And at least for
the general use cases, eg browsers, I doubt enough recursives will ever (or
be able to) support it for the stub to rely on receiving a recognized EDE.
It will always need to be a nice-to-have with the receiver able to provide
good behavior if no EDE (or an unrecognized new EDE) is received.

So no, I don't think categorization is necessary to make EDE useful.  In
fact, I think it would probably make things more complicated than necessary.