On Sep 22, 2011, at 2:10 PM, George, Wes wrote:
-----Original Message-----
From: ietf-bounces(_at_)ietf(_dot_)org
[mailto:ietf-bounces(_at_)ietf(_dot_)org] On Behalf Of Jari Arkko
Sent: Thursday, September 22, 2011 2:35 PM
To: ietf(_at_)ietf(_dot_)org;
draft-weil-shared-transition-space-request(_at_)tools(_dot_)ietf(_dot_)org
Subject: Re: Last Call: <draft-weil-shared-transition-space-request-03.txt>
(IANA Reserved IPv4 Prefix for Shared Transition Space) to Informational RFC
So here's what I would like to propose. The document goes forward but we make
a much clearer statement with regards to the implications both for
applications out there, as well as for subsequent IETF work:
- what types of impacts may be felt by the rest of the network (not the ISP
that is deploying NAT444)
- what kinds of application practices may be affected
- what IETF specifications may need revision due to this (e.g., do we need to
revise ICE etc)
Jari -
It's unclear from your statement if you're proposing adding the above to this
draft or to a subsequent draft.
To respond to your concerns and recommendation, I think that there are three
separate issues here that merit some discussion:
1) Does IETF recommend the practice of inferring address scope in IPv4 based
on address/bit value (the actual numbers), and then using this to trigger
different behavior based on that inferred scope?
Whether IETF recommends it or not, it is common practice in CPE today. As such,
I think we should recognize
and address the reality rather than ignore it in the name of architectural
purity. However, I am not convinced
that these drafts are the place to address it.
I don't believe the draft says that there is no link so much as we say that
hard-coding such assumptions and
making the assumption that all other addresses are globally reachable or have
global reachability is a poor
assumption. This draft doesn't change that fact and no clarification of scope
linkage would change the fact
that assuming your GUA (or presumed GUA) is globally unique or has global
reachability is a bad assumption
which is, nonetheless, an assumption built into many residential CPE devices
today.
2) Should draft-weil or draft-bdgks or both be formal updates to RFC1918 as
additional private-scope use cases?
I don't believe so. I believe that conflating these drafts with RFC-1918 would
only serve to further increase the
probability that someone would consider this additional space for the same
purpose. I would not oppose
adding a reference to RFC-1918 that links to these documents as additional
related considerations.
3) Independent of consensus on the state of the *draft* directing it to
happen, is there consensus on the *idea* that the /10 of IPv4 space should be
reserved as shared transition space?
I believe there is. Further comment below...
3) The reason I bring up consensus for the idea rather than the document is
that there seems to be some urgency behind getting *something* approved to
make the allocation happen, but it seems to be driving this strange behavior
to push through incomplete documents and sort out the details in subsequent
drafts.
Assuming that it is in fact necessary to get the allocation completed
rapidly, I'd rather see us split the logistics of making that happen from the
process required to produce consensus documents. This may be as simple as IAB
or IESG giving ARIN (and/or IANA) provisional clearance to allocate or
reserve the space on the belief that there is consensus to make the
reservation, but that we want our documentation in order before it is made
public for use. That removes any pressure to push the documents through
before they are ready, while still ensuring that the address space is
available when we are happy with the documentation. If for some reason the
document fails to achieve consensus in its final form, there's no harm in
then telling ARIN that they must release the reservation.
Additionally, if we're talking about pushing draft-weil back for that much
analysis, we're now talking about a non-trivial delay, and in that case it
may make sense to simply put the two drafts back together since weil was
supposed to go through quickly as a minimal draft with bdgks being the one
that the community spent more time on to ensure completeness and consensus.
There is urgency to make the space available for use, so, the split you
describe does not actually help. The urgency
is to make this space available before providers start having to deploy NAT444
without it, or, at this point, more
accurately, to limit the amount of NAT444 deployed using GUA, Squat Space, or
any of the other alternatives
that these drafts show are a significantly worse alternative vs. this /10
shared transition space.
Pushing draft weil back as you describe would be extremely harmful IMHO.
Owen
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