Re: [v6ops] I-D Action: draft-horley-v6ops-lab-00.txt

["Dale W. Carder" <[e-mail]>]

Thus spake Brian E Carpenter ([e-mail]) on Fri, Jun 11, 2021 at 10:22:51AM +1200:
> My concern about this draft is that it intentionally creates ambiguous address space, something we have very carefully avoided since the beginning of IPv6.

I'm not sure I worry as much about ambiguous as having more prefixes 
be marked "special", some of the implications of which seem may be at 
the heart of this proposal.

In draft-horley-v6ops-lab-00.txt,

"For instance, designing labs utilizing ULA fc00::/7
   [RFC4193] is problematic due to the random global ID requirement
   preventing hierarchical network prefix design possibilities."

Have the authors considered updating 4193?  Is the randomness the issue,
or is the resultant /48 the issue?  (of course, one could utilize
multiple random /48's as I think has been pointed out)

"Further, default address selection behavior [RFC6724] by end nodes
   may result in a depreferencing of such addresses and prevent lab
   deployments from accurately modeling their desired non-lab
   equivalents."

And this is the implication of having prefixes marked as special.  The
default behavior (which is only a SHOULD, i think) is not configurable or
at least not in a sane manner on a variety of platforms.  Presumably the
closed ecosystem devices (handhelds, particularly) have a goal of
minimizing user complaints and implement the table as specified, notably
with ULA at a lower precedence than GUA.  Would your document also need
to update 6724's table?  If I were a closed ecosystem vendor, once I
found out that $new_prefix gets assigned for lab use, I would probably
be inclined to move it fc00::/7 now that it becomes "special" rather
than as a stock GUA.

Dale