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]>]

On Sat, Feb 13, 2021 at 8:54 AM Ted Lemon <[e-mail]> wrote:

> On Feb 13, 2021, at 4:19 AM, Fernando Gont <[e-mail]> wrote:
>
> Well, whether we call it out or not, as per RFC4007:
>
>              scope(LL) < scope(ULA) < scope(GUA)
>
> So it's more about acknowledging facts than about introducing or needing a
> new scope.  The same applies to the addresses you mentioned before.
>
>
> No. scope(LL) < scope(ULA) and scope(LL) < scope(GUA) but scope(ULA) ?
> scope(GUA). That is, any particular ULA may or may not be global in scope.
>

Wait a minute! It doesn't say SOME addresses in the global scope are
globally unique, it says ALL addresses in the global scope are globally
unique. Unless each and every ULA address is globally unique, then ULA
can't be global scope.

And by what definition of global scope are the Local-Use IPv4/IPv6
Translation Prefix, the Discard-Only Prefix, and the IPv6 Benchmarking
Prefix global scope?

If all IPv6 addresses except the unspecified address, the loopback address,
and Link-Local addresses are global scope, then either the words "scope" or
"unique" are meaningless.


> The problem with admin scope is that it’s not a definitional scope, but
> rather an operational scope. Which may be the problem—we are using the term
> “scope” when that’s not specific enough—we could mean “by definition” or
> “in practice” scope, but we aren’t making that clear.  Of course, these are
> illustrative terms—I’m not saying we should switch to this terminology.
>

I think you are saying the idea of "IPv6 address scope" is meaningless
then, at least using the current interface uniqueness criterion.

Furthermore, since ANY GUA can be an Anycast address even GUA technically
fails the uniqueness criterion as stated.

If you are going to insist there is no third scope in between Link-Local
and Global Scope, then we should simply discard the uniqueness criterion as
any meaningful part of the definition of IPv6 address scope.

Thanks
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