Re: [v6ops] Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-ipv6-ula-scope-00.txt)

[David Farmer <[e-mail]>]

I think this is the right direction the previous draft indirectly defined a
new scope "non-global", I much prefer explicitly defining a new local scope.

I would add something like the following to better define the relationship
between the three scopes;

The boundary of the link-local scope is strongly defined, limiting the
extent of the link-local scope to an individual link. However, in contrast,
the boundary of the local scope is weakly defined, it is amorphous and
imprecise. In some instances, the extent of the local scope can be a single
site, in other instances, a group of unrelated sites, a single
organization, or even a cooperating group of organizations. Furthermore,
the extent of an individual instance of the local scope doesn't necessarily
remain constant, it may expand or contract over time as the local situation
dictates, for example when two organizations merge. Nevertheless, the
extent of the local scope doesn’t encompass the entirety of the Internet
which the global scope does.


On Tue, Jan 5, 2021 at 7:21 PM Fernando Gont <[e-mail]> wrote:

> Folks,
>
> Based on the recent discussion on the v6ops list
> (https://mailarchive.ietf.org/arch/msg/v6ops/b7r35HgOb-6dfxsDoW8c4FtGnZo//),
>
> I've posted this new I-D, meant to discuss the scope of ULAs:
>
> Title: "Scope of Unique Local IPv6 Unicast Addresses"
> I-D: https://tools.ietf.org/id/draft-gont-6man-ipv6-ula-scope-00.txt
>
>
> Short version of the story:
>
> ULAs are formally part of the GUA space. However, the characteristics of
> ULAs do not seem to match the definition of global scope from RFC4007
> (IPv6 Scope Addr Architecture). ULA seem to have a scope of
> scope(link-local) < scope(ULA) < scope(GUA).
>
> This is not only a terminology thing (which I think is nevertheless
> important to get right) but also has practical implications. For
> example, there's a python library that considers ULAs as "not global",
> and "private" -- contradicting the current RFC4291/RFC4193 specs.
>
> Prior to posting this document, we had some on-list discussion (on the
> v6ops list) and also some off-list discussion with some of you (bcc'ed).
>
> The opinions have been in one of these camps:
>
> 1) the current specs are coherent and there's no problem
>
> 2) There's a problem with the definition of "global scope" -- so ULAs
> *are* global scope, but global scope does not really stand for the
> definition in RFC4007.
>
> 3) The definitions in RFC4007 are correct, and thus the scope of ULAs is
> not really global, but scopee(link-local) < scope(ULAs) < scope(global)
>
>
> While this document does propose a way out (it assumes #3 above, and
> acts accordingly), I believe the first step is to agree on what "global
> scope" means and, subsequently, whether ULAs are really "global scope"
> or not. Since opinions on the topic have vary a lot (as noted above),
> I've posted this I-D and I'm sending this note for further input from
> the WG.
>
> Thanks!
>
> Regards,
> Fernando
>
>
>
>
> -------- Forwarded Message --------
> Subject: New Version Notification for draft-gont-6man-ipv6-ula-scope-00.txt
> Date: Tue, 05 Jan 2021 17:02:20 -0800
> From: [e-mail]
> To: Fernando Gont <[e-mail]>
>
>
> A new version of I-D, draft-gont-6man-ipv6-ula-scope-00.txt
> has been successfully submitted by Fernando Gont and posted to the
> IETF repository.
>
> Name:           draft-gont-6man-ipv6-ula-scope
> Revision:       00
> Title:          Scope of Unique Local IPv6 Unicast Addresses
> Document date:  2021-01-05
> Group:          Individual Submission
> Pages:          8
> URL:
> https://www.ietf.org/archive/id/draft-gont-6man-ipv6-ula-scope-00.txt
> Status:
> https://datatracker.ietf.org/doc/draft-gont-6man-ipv6-ula-scope/
> Htmlized:
> https://datatracker.ietf.org/doc/html/draft-gont-6man-ipv6-ula-scope
> Htmlized:
> https://tools.ietf.org/html/draft-gont-6man-ipv6-ula-scope-00
>
>
> Abstract:
>     Unique Local IPv6 Unicast Addresses (ULAs) are formally part of the
>     IPv6 Global Unicast address space.  However, the semantics of ULAs
>     clearly contradict the definition of "global scope".  This document
>     discusses the why the terminology employed for the specification of
>     ULAs is problematic, along with some practical consequences of the
>     current specification of ULAs.  Finally, it formally updates RFC4291
>     and RFC4193 such that the scope of ULAs is defined as "local".
>
>
>
>
> Please note that it may take a couple of minutes from the time of
> submission
> until the htmlized version and diff are available at tools.ietf.org.
>
> The IETF Secretariat
>
>
>
> _______________________________________________
> v6ops mailing list
> [e-mail]
> https://www.ietf.org/mailman/listinfo/v6ops
>


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