Comments on draft-ietf-idnabis-defs-10

Paul Hoffman phoffman at imc.org
Mon Aug 31 04:22:24 CEST 2009


At 4:08 AM +0200 8/31/09, jean-michel bernier de portzamparc wrote:
>I think I would support your proposition, but I am not sure I understand  "A pair of A-labels MUST be compared using a case-preserving comparison.".

A comparison between xn--Axdf and xn--axdf would yield "not matched".

>Moreover, the way you phrase it seems to integrate the case-preservation in the protocol, i.e. in the ACE and not to keep it as a part of its use?

Uppercase characters are not allowed in the U-labels anyway, so there is no reason to keep them in the A-labels.

>The rule proposed by Andrew Sullivan seems quite systematic and clear?
>
>1. The encoding of A-label1 according to [RFC3492] results in U-label1.
>2. The decoding of U-label2 according to [RFC3492] results in A-label2.
>3. A-label1 is equivalent to A-label2 according to DNS matching rules for labels.
>4. U-label1 is bistring equivalent to U-label2.

Well, no one spoke up for it. Personally, I find the introduction of A-label2 and U-label2 out of thin air to be confusing.

>We felt it addressed our point "References to the lower/uppercase image can be understood by DNS old-timers, but is confusing to newcomers, as it does not reflect the same functionality and because U-label/A-label lower/uppercase treatment is not the same." since everyone knows that punycode is case preserving.

I figure it is easier to remove the comparisons to regular-style DNS mapping than to try to show the differences.


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