Interoperability and updates

Paul Hoffman phoffman at
Fri May 9 18:16:16 CEST 2008

At 8:40 AM -0700 5/9/08, Erik van der Poel wrote:
>We are only trying to maintain or achieve interoperability. If we
>cannot get the representatives of the bigger players to agree, then
>it's hard to achieve interoperability, right? Sorry if some of my
>wording is deemed arrogant -- I'm just an engineer with ideas for

The IETF has a long history of wrestling with the question of 
interoperability, agreement among the parties who care, enforcement, 
resistance, and updates. Different people in the IETF (we are people, 
not a monolithic organization) have different views about the best 
way to write a standard to get the greatest interoperability. Some of 
those differences of opinion are very relevant in the current 

My view for IDNAbis (and IDNA2003) is that if the standard does not 
say that software that does a lookup needs to follow the rules for 
allowed and disallowed characters, meaningful interoperability will 
not be possible. Without lookup validation, registries will make 
mistakes (or possibly intentional mistakes) and then leave them in 
place with impunity. The reason we have had such good 
interoperability in IDNA2003 is the fact that most/all major software 
refuses to get to names that go against the standard.

This view makes updating the standard harder due to the 
already-discussed issues of delay in software updates. However, those 
issues are just as present if the standard does not require checking 
for lookup but does require checking for display. Programs that 
display IDNs need to be updated as often as those checking them 
before sending out queries. Thus, the standard does not gain any 
flexibility for updates unless both sides are made optional. A 
standard that only proposed limits on what could be registered would 
lead to near-zero interoperability due to the high number of mistakes 
that would be made.

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