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

Fernando Gont <> Wed, 06 January 2021 14:27 UTC

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To: Ted Lemon <>, David Farmer <>
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From: Fernando Gont <>
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Date: Wed, 6 Jan 2021 11:04:43 -0300
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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)
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Hi, Ted,

On 6/1/21 09:17, Ted Lemon wrote:
> On Jan 5, 2021, at 11:38 PM, 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.
> Actually, I think you’ve got it right here: the scope is “non-global.”

Indeed. But then, link-locals are non-global, too.

>> 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.
> There is at least one obvious problem with this definition: the term 
> “local.” ULAs aren’t really local, despite the name. 

FWIW, I suggested "local" as the scope as given the "L" in "ULA", it was 
the obvious choice. I don't mind using any other term. What really 
matters is to use consistent terminology.

So I guess possible options (other than "local scope") are:

* private scope?
* organizational scope?
* administrative scope?

> So I don’t really object to your text, but I do object to the name 
> “local.” How about “explicit”? That is, the scope of a ULA is explicit, 
> in the sense that it must be _made_ explicit by the user(s) of the ULA? 

mm.. not really. As a user of ULAs, it's impossible to tell if the scope 
ends up being just one link (think a CPE that locally generates a ULA 
prefix and advertises it in the only internal net/link), or multisite.

If not "local" or "explicit", maybe one of the others suggestions above 
would work?


Fernando Gont
SI6 Networks
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