Touchstones for "Mapping"

Vint Cerf vint at google.com
Thu Apr 2 16:45:32 CEST 2009


mark, my point was that under the rules of IDN, you can convert from A- 
Label to U-label with assurance of precision. So you can cater to  
human readability. Storing in U-label for doesn't work for non-IDN  
aware applications and might even confuse them. This is a presentation  
issue surely?

v


Vint Cerf
Google
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vint at google.com




On Apr 2, 2009, at 10:33 AM, Mark Davis wrote:

> I think the main storage benefits are human readability. It is much
> easier to read:
>
> href="http://εύβοια.el"
> rather than
> href="http://xn--mxabir3a6f.el"
>
> or in some XML:
>
> <url>http://εύβοια.el</url>
> rather than
> <url>http://xn--mxabir3a6f.el</url>
>
> But there are other issues: URL's are stored all over the place. If I
> have one in an SQL database, I want to be able to do a SELECT Data
> WHERE Url LIKE 'http://εύβοια%' and not 'http://xn--mxabir3a6f 
> %'.
>
> And there are formal problems, because substrings in Unicode space
> don't match substrings in PunyCode space. that if my URL were
> "http://εύβοια-ξενοδοχείο.el" (a made up example),  
> then its A-Label
> form is "http://xn----vlbedmcdb5a7bjigbc9jyd.el". The SELECT of
> 'http://xn--mxabir3a6f%' would fail. Moreover, Url LIKE
> 'xn--mxabir3a6f%' can even return false results, strings whose U-Label
> doesn't start with 'http://εύβοια%'
>
> Mark
>
> On Thu, Apr 2, 2009 at 05:50, Vint Cerf <vint at google.com> wrote:
>> Martin,
>>
>> I continue to be somewhat confused by logic that suggests that  
>> storage benefits from being in the U-label form.   A-labels are  
>> almost de facto normative since they work withIDN-aware and IDN- 
>> unaware appllications. IDN-aware applications should be able to  
>> generate the corresponding U-label for presentation. IdN-unaware  
>> applications. Won't even recognize a U-label domain name as valid  
>> IWoild think. Consequently, storage in A-label form seems the  
>> rational choice. If you disagree, it must be because you see a flaw  
>> in the reasoning above. Can you clarify? V
>>
>> ----- Original Message -----
>> From: idna-update-bounces at alvestrand.no <idna-update-bounces at alvestrand.no 
>> >
>> To: Harald Alvestrand <harald at alvestrand.no>
>> Cc: Andrew Sullivan <ajs at shinkuro.com>; idna-update at alvestrand.no <idna-update at alvestrand.no 
>> >
>> Sent: Thu Apr 02 03:37:30 2009
>> Subject: Re: Touchstones for "Mapping"
>>
>> There are two sides here, the protocol correctness and
>> the content correctness. By content correctness, I mean
>> whether the link e.g. goes to the intended page.
>> Completely impossible to check with punycode, of course.
>>
>> Regards,   Martin.
>>
>> On 2009/04/02 16:56, Harald Alvestrand wrote:
>>> Martin J. Dürst wrote:
>>>> I very much agree with Harald. We are working on IDNs because we  
>>>> want
>>>> humans to be able to easily read domain names in their script.  
>>>> Storing
>>>> them as A-Labels when there is a reasonable chance that humans will
>>>> have a look at them (e.g. in HTML or XML source, email source,...)
>>>> is against the very intent of IDNs. Authors are humans, too, even
>>>> if they work on plain text :-!
>>> I can argue the other side of the argument for HTML and XML,  
>>> though.....
>>> the main thing being that humans who *enter* IDNs in Unicode form
>>> without the benefit of conformance-enforcing software interfaces  
>>> will
>>> just about always get them wrong (due to bizarrities of case,
>>> compatibility characters and other weirdnesses).
>>>
>>> If they enter A-labels by hand, it's pretty certain they've
>>> cut-and-pasted them.
>>>
>>>               Harald
>>>
>>>
>>> _______________________________________________
>>> Idna-update mailing list
>>> Idna-update at alvestrand.no
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>>>
>>
>> --
>> #-# Martin J.Dürst, Professor, Aoyama Gakuin University
>> #-# http://www.sw.it.aoyama.ac.jp   mailto:duerst at it.aoyama.ac.jp
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