Re: Running code (Was: I-D Action: draft-ietf-6man-ipv6only-flag-03.txt)

[Suresh Krishnan <[e-mail]>]

Hi Tim,

> On Oct 23, 2018, at 5:24 PM, Tim Chown <[e-mail]> wrote:
> 
>> On 23 Oct 2018, at 19:26, Suresh Krishnan <[e-mail]> wrote:
>> 
>>> On Oct 23, 2018, at 2:05 PM, Sander Steffann <[e-mail]> wrote:
>>> 
>>> Hi,
>>> 
>>> Changed the subject because this discussion is now moving away from any specific draft.
>>> 
>>>> That's kind of my take, as well However, I think that asking for an
>>>> implementation of the ipv6-only flag is a requirement that I have never
>>>> seen for taking new work or publishing it, so it would be unfair to ask
>>>> that to the authors of this particular I-D.
>>> 
>>> I'd like that to become the norm though. Having a running prototype can help enormously when writing specifications. My preference would be to move back to a base principle of running code and rough consensus, instead of only rough consensus.
>> 
>> If the WG decides to go on this path, I will be fully supportive of that. This model has worked out well for idr (see https://trac.ietf.org/trac/idr/wiki#ImplementationRequirement). What I am uncomfortable with is that criterion being *selectively* applied to this draft as a prerequisite for progress. 
> 
> I think there are good grounds in this case.  There is (apparently) no vendor interest, but it's also a very vague document, where if any vendors do decide to implement, it's highly likely that those implementations will result in different host behaviour.  

I think it would be better to clear up the vague pieces so that we can have a reasonable conversation about the draft. I personally think just the existence of an implementation is not a sufficient step to clear this up. Let me give you an example to show why I think so. I had an implementation of the M and O bit flags on the router side and I have seen several implementations of the flags on the host side, but the results were still a crapshoot. You could not tell up front for a given combination of the flags what a host would do. I have had customers ask me “I want the host to use stateless DHCPv6 to get config information but I do not want them to try to use stateful DHCPv6 (IA_NA)”. I told them to use M=0 and O=1 but the results were all over the place. 

> Thus exploring interpretations of the draft on specific platforms, and observing the resulting behaviours and interactions, seems a pretty prudent step.  This may help refine the draft to be more specific, and uncover perspectives that as yet have not been considered.  It's not like the draft needs to be rushed through quickly.

Yep. We have been fine this long without it. Agree that we should not rush it.

Thanks
Suresh