Re: draft-ietf-v6ops-addcon

[JINMEI Tatuya / 神明達哉 <Jinmei_Tatuya@isc.org>]

At Mon, 9 Jun 2008 04:49:34 +0200,
"Gunter Van de Velde (gvandeve)" <gvandeve@cisco.com> wrote:

> The question here is if different then /64 prefix considerations should
> be given?
> 
> At the moment any prefix NOT starting with '000' must have a 64bit
> network ID.
> The addcon draft documents items that 'if' one has to divert from this 
> recommendation (against any IETF doc) to at least be aware of other 
> restrictions regarding anycast, etc....
> 
> Now at IESG review that is contested, and the editors are trying to 
> understand if sections 3.1 (larger then /64) and 3.3 (smaller then /64)
> should 
> be removed or not?
> 
> I think it is good content as reality seems to indicate that people DO
> use 
> different then /64 prefix addresses.
> 
> Any thoughts? Flames? Screams?

We should keep both of these section.  This is indeed a very confusing
point, and we had a hard time providing reasonable explanation of this
prefix/IFID length issue when we revised the stateless addrconf
document (now published as RFC4862).  The following excerpt from
RFC4862 may help in this context, too.

      Note that a future revision of the address architecture [RFC4291]
      and a future link-type-specific document, which will still be
      consistent with each other, could potentially allow for an
      interface identifier of length other than the value defined in the
      current documents.  Thus, an implementation should not assume a
      particular constant.  Rather, it should expect any lengths of
      interface identifiers.
(from Section 5.5.3)

I know it's still not crystal clear, but it was a best effort
compromise to make the description as consistent with other documents
as a possible, while still respecting existing
implementation/operational experiences and providing greater
flexibility.

---
JINMEI, Tatuya
Internet Systems Consortium, Inc.