Re: draft-bourbaki-6man-classless-ipv6-00

[神明達哉 <[e-mail]>]

At Tue, 06 Jun 2017 23:30:30 +0000,
Job Snijders <[e-mail]> wrote:

> > >> But that is exactly what the draft does *not* do. Nobody would
> > >> change a single instruction in existing code as a result of this
> > >> draft. (I agree with you that some O/S stacks may need fixing, but
> > >> they already need fixing.)
> > >
> > > is this draft exactly:
> > >
> > >    IPv6 unicast routing is based on prefixes of any valid length up to
> > >    128 [BCP198].  Interface Identifiers should be 64 bit long except
> > >    when the addresses are manually configured, or by exceptions defined
> > >    in standards track documents.  For example, [RFC6164] standardises
> > >    127 bit prefixes on inter-router point-to-point links.  The rationale
> > >    for using 64 bit Interface Identifiers can be found in [RFC7421]
> > >
> > > ?
> >
> > Yes. Put those words in 4291bis and I will be very happy. Oh ;-).
>
> I recall a small but vocal group arguing fiercely against that text
> adjustment, so here we are.

As several people including myself have already pointed out, it's very
hard for ordinary readers to understand that's really what
draft-bourbaki-6man-classless-ipv6-00 tries to propose.  It will have
to be heavily revised to convey that message.

As for the above text, my recollection is that some people (I don't
know if that was a small group, btw - to me both groups looked equally
vocal and equally small/large) were against one specific point in
text like the above one:

- "should be 64" instead of "must be 64" (but in my understanding they
  were/are okay with "except when the addresses are manually
  configured")

It's also not clear to me whether the real intent of
draft-bourbaki-6man-classless-ipv6-00 includes the subtle (but
seemingly very important for those who were "fiercely against" it)
change from "must" to "should".  I guess if the authors of
6man-classless-ipv6 are actually also happy/okay with this one:

    IPv6 unicast routing is based on prefixes of any valid length up to
    128 [BCP198].  Interface Identifiers must be 64 bit long except
    when the addresses are manually configured, or by exceptions defined
    in standards track documents.  For example, [RFC6164] standardises
    127 bit prefixes on inter-router point-to-point links.  The rationale
    for using 64 bit Interface Identifiers can be found in [RFC7421]

then there will be no dispute or further time wasting (we'll still
need to decide what to do with the magic leading bits of 000 in terms
of the interface identifier length, but if we can agree at this level
this will be a relatively minor point to address).

--
JINMEI, Tatuya