On 12/1/11 4:27 PM, Ted Hardie wrote:
On Wed, Nov 30, 2011 at 6:14 PM, Pete Resnick <presnick(_at_)qualcomm(_dot_)com
<mailto:presnick(_at_)qualcomm(_dot_)com>> wrote:
The problem described in the draft is that CPEs use 1918 space
*and that many of them can't deal with the fact that there might
be addresses on the outside interface that are the same as on the
inside interface*. The claim was made by [Robert], among others,
that only 192.168/16 space was used by such unintelligent CPEs. I
believe I have seen the claim that 10/8 space is also used in
unintelligent equipment that can't deal with identical addresses
inside and outside. Is there reason to believe that within the ISP
network / back-office etc. that there is equipment that can't deal
with 17.16/12 space being on both the inside and outside? I
haven't seen anyone make that specific claim.
If we know that 172.16/12 used both inside and outside will break
a significant amount of sites that CGNs will be used with, we can
ignore this argument. But if not, then let's rewrite the document
to say that CGNs should use 172.16/12 and that any device that
wants to use 172.16/12 needs the ability to deal with identical
addresses on the inside and the outside interface. Of course, all
equipment should have always been able to deal with identical
addresses inside and outside for all 1918 addresses anyway. But if
we think the impact of using 172.16/12 for this purpose will cause
minimal harm, then there's no compelling reason to allocate new
space for this purpose.
I wrote a response to Brian's original statement then deleted it
because I assumed others would ignore it as clearly last minute and
ill-researched. Apparently, that was wrong. There are enterprises
that currently use 172.16/12. (There are enterprises which use every
tiny piece of RFC 1918 space.)
Ted, your response does not address what I said at all. Not one bit.
Let's assume that *every* enterprise used every last address of
172.16/12 (and, for that matter ever bit of 1918 space). That's
irrelevant and still does not address my question. The question is
whether these addresses are used BY EQUIPMENT THAT CAN'T NAT TO
IDENTICAL ADDRESSES ON THE EXTERIOR INTERFACE. I am happy to accept an
answer of, "Yes, all 1918 address space is used by such equipment", but
nobody, including you, has actually said that.
*Any* piece of the current RFC 1918 space you attempt to define as
being used for this will conflict *somewhere*. Anyone who happened to
chose this for an enterprise deployment and gets stuck behind a CGN
would be forced to renumber, in other words, because of this statement.
That statement does not logically follow from "all 1918 address space is
used". You are missing a premise: "There exists equipment that is used
in all of that space that can't handle identical addresses on the
interior and exterior interface."
The current draft says that the reason 1918 space can't be used is that
equipment that deals in 1918 address space is hosed if 1918 addresses
are used on their external interface. Brian claimed that perhaps
172.16/12 space might not be used by that equipment. Robert claimed that
perhaps only 192.168 and 10.0.0.x addresses are used by that equipment.
So the question I posed was, "Does any of *that* equipment use 172.16/12
(or 10.x/16) space?" Nobody has said "yes".
And *I'm* still not claiming that the answer is "No." I simply don't
know. But I'm inclined to hear from anybody to indicate that there is
*any* evidence that the answer is "Yes". That would make me much more
comfortable in concluding that new specialized address space is the
better horn of this bull to throw ourselves on.
pr
--
Pete Resnick<http://www.qualcomm.com/~presnick/>
Qualcomm Incorporated - Direct phone: (858)651-4478, Fax: (858)651-1102
_______________________________________________
Ietf mailing list
Ietf(_at_)ietf(_dot_)org
https://www.ietf.org/mailman/listinfo/ietf