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

Fernando Gont <fgont@si6networks.com> Wed, 06 January 2021 05:28 UTC

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Subject: Re: [v6ops] Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-ipv6-ula-scope-00.txt)
To: David Farmer <farmer@umn.edu>
Cc: "6man@ietf.org" <6man@ietf.org>, IPv6 Operations <v6ops@ietf.org>
References: <160989494094.6024.7402128068704112703@ietfa.amsl.com> <6fe3a45e-de65-9f88-808d-ea7e2abdcd16@si6networks.com> <CAN-Dau344H7xgD0Q_O54c=R08zFRFjToO8BHt=ssauxgEH7ynA@mail.gmail.com>
From: Fernando Gont <fgont@si6networks.com>
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Date: Wed, 6 Jan 2021 02:28:36 -0300
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Hello, David,

Thanks a lot for your feedback! In-line....

On 6/1/21 01:38, David Farmer wrote:
> 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.

Good point.



> 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. 

Following the terminology in RFC4007, I wonder if this last bit should 
be expressed as:
"the extent of an individual instantiation of a local scope (i.e., a 
zone), does not necessarily remain constant..."?


>     Nevertheless, the extent of
>     the local scope doesn’t encompass the entirety of the Internet which
>     the global scope does.

A remaining item to figure out here is:

According to RFC4007, you can't have to instantiations of the same 
scope. One way to analyze this is

1) that this doesn't apply to ULAs, or,

2) That it's impossible to tell the specific extent of a local scope. As 
a result, all instantiations of local scopes are considered to be 
different zones, and hence you are free to have as many instantiations 
of "local scope" as you wish.

(RFC4007 defines "zone" to be an instantiation of "scope").

Thoughts?

Thanks!

Regards,
-- 
Fernando Gont
SI6 Networks
e-mail: fgont@si6networks.com
PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492