Subject: RE: Let's abolish scope [Re: Unicast scope field (was: Moving forward on Site-Local and Local Addressing)]

From: "Michel Py" <[email-masked]>
Date: Fri, 8 Aug 2003 08:30:41 -0700

Brian,

> Brian E Carpenter wrote:
> I don't recall that we ever promised to support scoping
> of unicast addresses.

Not explicitely, but the idea about IPv6 has been since the beginning
that it would better than IPv4 with more bits (which we could have
delivered years ago). One of these things that could make it better is
scoping for unicast addresses. Specifically, I do not see how we could
remove ambiguity of private addresses at this time without something
like scoping.

> RFC 1752 refers to the scope field in multicast addresses,
> which I certainly don't propose to abolish.

Separate issue; I was not thinking about multicast at all.

> I don't see why the lack of explicit scope for IPv6
> unicast is an inhibitor.

See above. As I said earlier, it has good sides and bad sides. From the
enterprise network manager point of view, I do think that many actually
care a lot about what kind of simplification scoping can bring in terms
of access-control and security. Specifically, although the routers will
continue to think in terms of IPO addresses, scoping could bring some
automation in building default access-lists that would be nice to have.

Michel.

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From: "Michel Py" <[email-masked]>
Date: Mon, 11 Aug 2003 11:41:07 -0700

Brian,

> Brian E Carpenter wrote:
> Quite correct. What I'm pushing back on is the idea that three
> levels of scope (link, local, global) capture much of anything
> useful. If we were talking about scope between say 0 and 255,
> where 0 means link, 255 means global, and 1..254 are user
> defined, we might be able to define something of value to
> enterprise network operators.

Sounds good, but do you think that moving the scope definition to the
user will bring any breakthrough in getting this new scoped architecture
doc out of the door though? I have not thought much about it but the
initial reaction is that it would make things even worse.

Michel.