Subject: RE: poposed changes to the scoping architecture draft

From: "Richard Draves" <[email-masked]>
Date: Wed, 20 Mar 2002 11:19:40 -0800

Sorry I wasn't reading correctly - obviously you were discussing the
unspecified address not the loopback address!!

It's not clear to me that the unspecified address has a well-defined
scope level...

> -----Original Message-----
> From: Richard Draves [mailto:[email-masked]] 
> Sent: Wednesday, March 20, 2002 11:01 AM
> To: Francis Dupont; JINMEI Tatuya / ????
> Cc: Markku Savela; [email-masked]
> Subject: RE: poposed changes to the scoping architecture draft 
> 
> 
> >    > Btw. what is the scope level of address "::"?  = 0?
> >    
> >    Hmm, good question.  I personally think "::" can be treated as a
> >    global scope with regards to the scope architecture,
> > because it does
> >    not cause ambiguity about the "zone".  And, in fact, our current
> >    implementation treats "::" as a global address for 
> > convenience, and it
> >    works without anomaly.
> 
> I think the loopback address should be link-local scope (on a 
> virtual loopback link). It is obviously not global scope, 
> since it does not uniquely specify an interface.
> 
> Note that draft-ietf-ipv6-default-addr-select-07.txt section 
> 2.4 also refers to this issue.
> 
> Rich
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From: JINMEI Tatuya / 神明達哉<[email-masked]>
Date: Thu, 21 Mar 2002 12:29:51 +0900

>>>>> On Wed, 20 Mar 2002 11:19:40 -0800, 
>>>>> "Richard Draves" <[email-masked]> said:

> unspecified address not the loopback address!!

Okay.

> It's not clear to me that the unspecified address has a well-defined

Perhaps we have two choices:

1. treat :: as global
2. does (explicitly) not define the scope type (level) of ::

Even the choice 2 will make the document clear, and it will not cause
a problem in a practical point of view.

					JINMEI, Tatuya
					Communication Platform Lab.
					Corporate R&D Center, Toshiba Corp.
					[email-masked]
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From: Steve Deering <[email-masked]>
Date: Wed, 20 Mar 2002 21:51:02 -0800

>a problem in a practical point of view.

I think of :: as indicating the absence of an address, in which case
it doesn't have any scope.  For those who feel the need to assign a
scope value to ::, it's probably safest to treat it as link-local
(for example, to ensure that a router receiving a packet with a
source address of :: is not forwarded to another link).

Steve

---

From: Brian Haberman <[email-masked]>
Date: Thu, 21 Mar 2002 07:51:01 -0500

> source address of :: is not forwarded to another link).

I agree with the concept of :: not having any scope.  If I had to pick
a scope for the unspecified address, it would appear to have more of
the characteristics of the multicast interface-local scope.  But since
it is not a multicast address, link-local should suffice.

Brian