Ted Hardie wrote:
There is a long and "interesting" history here, but it isn't
directly
relevant
to this discussion. I think it would be valuable to focus the
discussion on Site Local,
rather than on RFC 1918 space.
The reason for bring 1918 into the discussion is that prior to NAT,
there was a market demand for private address space. That demand hasn't
gone away, and the non-NAT users of that space are completely
disenfranchised in this discussion because they have seen no need to
worry about it given there is a comparable space defined for IPv6.
I think you may underestimate how much trouble this might cause in
applications.
As Dave Crocker noted in response to Margaret Wasserman's
presentation to the APPs Open Area meeting, applications have
been designed so that
they
do not know and don't need to know anything about network
topology.
If you
require applications to understand the consequences of different
unicast address
scopes, you are changing a pretty fundamental assumption.
While it is
theoretically
possible to change that assumption, it is a major piece of
work, and I
believe that
the "sense of the room" was that the advantages of Site Local
were not
worth that
amount of work.
I am not arguing that every app need to know about topology. If this is
such a big deal, we should simply fix the API so that by default it only
returns global scope addresses, then add a new function for those apps
that are interested in the limited scope. This doesn't sound like rocket
science, and the arguments against it are coming across like 'we don't
want to change because it is too much work'. Rather than argue that
nobody can ever use a new feature, the basic approach should be that you
don't have to unless you want to.
As you note, this is subject to discussion and
confirmation on
the mailing list and, ultimately, to the consensus of the IETF as a
whole.
And it has yet to be formally raised by the chairs on the WG list, so if
it gets to IETF last call, it will be ripe for an appeal.
Tony
Margaret's presentation, for those not at the APPs open area, was
derived from her
draft, found at
http://www.ietf.org/internet-drafts/draft-wasserman-ipv6-sl-impact-
02.txt.
See especially section 3.7.