Re: [dhcwg] Last Call: <draft-ietf-dhc-anonymity-profile-06.txt> (Anonymity profile for DHCP clients) to Proposed Standard

[Lorenzo Colitti <[e-mail]>]

On Tue, Feb 16, 2016 at 9:29 PM, Brian Haberman <[e-mail]>
wrote:

> > Well, section 4 of draft-ietf-dhc-anonymity-profile-07 says:
> >
> >    The choice between the stateful and stateless scenarios depends on
> >    flag and prefix options published by the "Router Advertisement"
> >    messages of local routers, as specified in [RFC4861].  When these
> >    options enable stateless address configuration hosts using the
> >    anonymity profile SHOULD choose it over stateful address
> >    configuration, because stateless configuration requires fewer
> >    information disclosures than stateful configuration.
> >
> > That seems pretty close from what you want, at least as far as "stateful
> DHCPv6" is concerned.
>
> I would agree that the above text covers what I interpret as Lorenzo's
> concern.
>

My concern is not with the intent, it's with the wording.

The business of this draft is to provide guidance to implementers. I am an
implementer: I wrote the DHCP client currently used in a host OS, and while
said OS does not yet support DHCPv6, I am likely to involved with that as
well if/when that happens. So I am squarely in the target audience for this
document - but as has become clear from this thread, I did not understand
the text correctly, even though I was actually paying attention It took a
specific response from Christian and an explanation from a colleague before
I actually understood what the implications were for host behaviour. We
should try to ensure other implementers do not misunderstand the text like
I did, by making it clearer.

Let me suggest text again:

   When these options enable stateless address configuration (i.e., when
   the A flag in a Prefix Information Option is set to 1) hosts using the
   anonymity profile SHOULD perform stateless address configuration
   and SHOULD NOT use stateful DHCPv6, because stateless configuration

I don't see how that text is different from the text that's already in the
draft, except it actually provides clear guidance. Why not use it?