Bidi simplification (Re: IDNA protocol checking/processing)

Michel Suignard michelsu at
Mon Dec 3 18:47:31 CET 2007

> From: Harald Tveit Alvestrand [mailto:harald at]
> Michel,
>--On 30. november 2007 18:36 -0800 Michel Suignard
><michelsu at> wrote:
>> I have proposed in the past new text for the bidi rules which does
>> not require to run the Unicode bidi algorithm (as suggested in
>> section 4 of draft-alvestrand-idna-bidi-01.txt referenced in test
>> 4). By special casing the NSM category it is my belief we can avoid
>> that step.
> can you make those suggestions again, within the context of the
> current version of the BIDI document?
> I'm afraid that I've lost the context of what you're referring to.
> I've been quite unhappy that there has been so little commentary
> on the latest revision of the BIDI document, and would very much
> like to have some more competent input on it.
> But I believe that the correct context for that discussion is the
> bidi document, not the protocol document - if we can get bidi
> right, the protocol document should have absolutely no need to do
> anything but refer to it.

Harald, I respectfully disagree, at least in the current forms of the two documents. As of now, the bidi document refers to a change in RFC 3454 (stringprep) while the protocol document does w/o any external string preparation step, so it seems difficult to treat the bidi document as an appropriate referenced document. At minimum you should update the bidi document to reflect the new protocol document and be a proper reference. You should probably insert a new clause between 4 and 5 detailing the appropriate bidi test step to be used by the new idn protocol (ref clause 4.4 of the protocol document). Note that this message as well as the previous was taking into consideration both your document and the protocol document.

I also saw the bidi document as a problem statement with a suggested solution in an external protocol document (RFC 3454 or successor). If the solution can be expressed in simple terms I don't see why the solution cannot be explicitly part of the protocol with a link to the bidi document for rationale. I don't see an issue with my proposed text be part of both the rationale (bidi document) and the protocol.

The bidi solution that I had extracted in my previous message was part of a larger document I had sent to this group on March 12th 2007, well before your last version of the bidi document at and was addressing roughly the same scope as the new protocol document. I have no intend to make it into a competitive proposal, but would like some of its principles incorporated in a final protocol document. I also got very little feedback on my own earlier contribution so your 'unhappiness' for lack of comments is somehow shared ;-)

In general, it will be easier for us external contributors to make more useful contributions once the framework is in place. Getting the protocol piece in place, even in its current incomplete shape has been a vast improvement. Once you modify the bidi document to be in better sync with the protocol it will be easier for all of us to contribute.

Best regards,


More information about the Idna-update mailing list