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

[Brian E Carpenter <[e-mail]>]

On 15-Jun-21 07:14, Dale W. Carder wrote:
> 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?

I'd say that isn't even necessary. The #1 rule is that fc00::/7 must be
filtered at the IGP/EGP boundary. Inside that boundary, where's the harm
(for lab tests, staging, or training)?

The point about default address selection precedence is actually
more tricky, since it would need a config update on every host.

   Brian

> 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
>