Subject: RE: Your Appeal Regarding Site-Local Deprecation (Was: Consensus on Site-Local Addressing)

From: Margaret Wasserman <[email-masked]>
Date: Mon, 28 Apr 2003 17:02:02 -0400

Hi Tony,

We have considered your appeal regarding the IPv6 WG consensus
to deprecate site-locals.  Based on our analysis, we believe
that your appeal makes the following points:

   (1) You believe that deprecating IPv6 site-local unicast
       addressing is an incorrect technical choice that places
       the work output of the IPv6 WG in jeopardy.

   (2) You believe that the question asked by the chairs
       was insufficiently clear to be understood properly
       by the WG.

   (3) You do not believe that there is rough consensus to
       deprecate IPv6 site-local addressing, because people
       provided different reasons for why they believe that
       IPv6 site-local addressing should be deprecated.  In
       particular, some people want to deprecate the particular
       model of site-local addressing defined in the scoped
       addressing architecture (ambiguous, scoped addresses),
       while others do not believe that we need a local
       addressing mechanism at all.

   (4) You believe that it is invalid for the IPv6 WG to
       deprecate site-local addressing without publishing an
       IPv6 WG document that analyzes the operational requirements
       for local addressing.  Without this analysis document, you
       believe that the IPv6 WG has made an uninformed choice.

We will now respond to each of your points.

--

Point (1):

The chairs do not believe that deprecating IPv6 site-local addressing
is an incorrect technical decision that will place the work output
of the IPv6 WG in jeopardy.

The consensus was to "deprecate" the usage of site-local addressing
instead of simply removing it. This was done purposely to avoid
interference with any current implementations or deployments that might
use site-local addressing.  In addition to the time it will take to
formally deprecate site-local addressing by publishing an RFC, the WG
understands that it will take some time after the publication of an RFC
for implementations to change.  The decision to deprecate site-local
addressing, rather than simply removing it, was made to avoid harm
to IPv6.

In fact, we believe that the previous disagreement over the usage
of IPv6 site-local addressing was damaging to the WG, and that our
lack of consensus was delaying our work, particularly on the IPv6
scoped addressing architecture.  The consensus to deprecate
site-local addressing will allow us to move forward and complete
our work.

---
Point (2):

The question was:

     "Should we deprecate IPv6 site-local unicast
     addressing?"  Possible answers were YES or NO.

The chairs believe that this question was sufficiently clear
to be understood by the WG.  This is supported by the following
points:

     - Over 200 people responded to the question.

     - Many of the responses on the list (both YES and NO
       responses) included reasons or comments that
       followed from the question in a way that indicated
       that the responders understood the question.

     - There were only three requests for clarification of
       this consensus call on the mailing list, two of which
       were procedural.  All of these requests were answered
       promptly by the chairs.

     - The chairs sent the consensus results to the list
       over two weeks ago, including a course of action for
       the deprecation of site-local addressing.  There
       have been no objections from people who originally
       expressed YES opinions that the chairs' course of
       action fails to match their expectations.

---

Point (3):

The chairs do not believe that consensus on an issue is
invalidated by the fact that people have multiple reasons for
coming to the same conclusion.  We suspect that this happens
in most WG consensus calls, and this is not a reason to
invalidate the consensus.

All of the groups that you mentioned in your message agreed
that IPv6 site-local unicast addressing should be deprecated.
They may disagree on what we should do after deprecating site-
local addressing, but that does not invalidate the consensus
on this point.

---

Point (4):

It is true that the IPv6 WG has not produced a WG document that
analyzes the operational requirements for local addressing.  However,
we do not believe that this is a reason to invalidate the IPv6 WG
consensus to deprecate IPv6 site-local unicast addressing.

There has been considerable discussion and analysis of site-
local addressing performed over the past year, including
extensive discussions during three IETF sessions.  There have
also been several drafts published on the subject, including one
draft that attempts to analyze the cost/benefit trade-offs
of site-local addressing.

This period of discussion has offered sufficient time for anyone
who has an operational need for any of the currently-defined usage
models of site-local addressing to document those requirements in
an Internet-Draft and/or to discuss those requirements on the IPv6
mailing list.

During our discussions, several operational benefits of site-local
addressing have been raised on the IPv6 WG mailing list,
including benefits for disconnected sites, intermittently-
connected sites, renumbered sites, etc.  We have also uncovered
several issues and complexities caused by the current model of
ambiguous, scoped site-local addressing, and we have determined
that this particular model places burdens on other parts of the
TCP/IP protocol suite, particularly routing protocols and
applications.

In a recent phone discussion and in your appeal clarification, you
have indicated that the chairs should void responses from
people who do not think that the IPv6 WG should specify any type
of local addressing mechanism, because you believe that those
responders are uninformed about the operational conditions that
require the use of local addressing.

While operational necessity is certainly an appropriate argument
to raise in support of your position that the IPv6 WG should
specify some mechanism for local addressing, the fact that you
disagree with the reasons that some people offered for why they
want to deprecate the current IPv6 site-local unicast addressing
mechanism does not invalidate their contribution to this consensus
call.

It is the opinion of the chairs that the IPv6 WG did have
sufficient information to make an informed decision regarding
whether or not to deprecate IPv6 site-local unicast addressing.

---

So, to summarize, the chairs do not agree with the points that you
have raised in your appeal, and we do not agree to overturn the
consensus of the IPv6 WG based on the issues that you have raised.

Tony, while we disagree with your position on this particular
issue, we do respect your contributions to the IPv6 effort and
we realize that your appeal is motivated by your desire to do the
right thing for IPv6.  We hope that you will accept our response
to your appeal and focus on working to define the local addressing
problem and solutions as we outlined in our email to the list. We
think it is important for the working group to move forward on this
issue.

Best Regards,

Bob Hinden & Margaret Wasserman
IPv6 WG Chairs 

--------------------------------------------------------------------
IETF IPng Working Group Mailing List
IPng Home Page:                      http://playground.sun.com/ipng
FTP archive:                      ftp://playground.sun.com/pub/ipng
Direct all administrative requests to [email-masked]
--------------------------------------------------------------------

---

From: "Tony Hain" <[email-masked]>
Date: Mon, 28 Apr 2003 18:38:26 -0700

>        addressing mechanism at all.

I was not objecting to 'different reasons'. The specific complaint is
that many of YES votes were for removing the architectural construct, or
need for applications to deal with addresses that are only accessable
over a limited scope. That is not in the purview of the IETF to decide,
it is an operational decision of the network manager. Those votes are
not valid as a result. 

> Point (1):
> 
> The chairs do not believe that deprecating IPv6 site-local 
> addressing is an incorrect technical decision that will place 
> The consensus was to "deprecate" the usage of site-local 
> addressing instead of simply removing it. 

By asking an ambiguous question, it is easy to insert your
interpretation as the collective consensus. How convenient. 
SF question --
... how many people think that we should deprecate SL addressing? 
Mail list question --
Should we deprecate IPv6 site-local unicast addressing? 

Neither of those mention 'usage'. In fact if you watch the video of SF,
you will find that you spent much more time talking about elimination
than anything else.

> This was done 
> purposely to avoid interference with any current 
> implementations or deployments that might use site-local 
> addressing.  In addition to the time it will take to formally 
> deprecate site-local addressing by publishing an RFC, the WG 
> understands that it will take some time after the publication 
> of an RFC for implementations to change.  The decision to 
> deprecate site-local addressing, rather than simply removing 
> it, was made to avoid harm to IPv6.

There was no decision. You had an inconclusive discussion with Keith,
then later a vague discussion with Thomas about a 'hand wave'. Neither
of those even come close to a decision, let alone a WG decision. Are we
supposed to just say YES to any ambiguous question you ask, so you can
make up the content of the consensus later?

> 
> In fact, we believe that the previous disagreement over the 
> usage of IPv6 site-local addressing was damaging to the WG, 
> and that our lack of consensus was delaying our work, 
> particularly on the IPv6 scoped addressing architecture.  

While you may believe that the disagreement over SL was delaying the
work, most of those disagreements stemmed from a lack of agreement over
the fundamental requirements. Removing SL does not solve the basic
problems that need to be addressed in the scoped addressing
architecture.

> The 
> consensus to deprecate site-local addressing will allow us to 
> move forward and complete our work.

No it won't. A scoped address architecture document that ignores the
reality of addresses that are only reachable within a limited part of
the network is incomplete on its major point. It is absolutely useless
to pretend that we have a document that discusses a scoped architecture
when the case for the majority of nodes in the Internet is missing.

> to be understood by the WG.  

Clearly you didn't watch the video of the SF meeting. Why would Thomas,
Keith, Dave, and Christian make a specific point of trying to clarify
the question if it was clear to begin with? Since the question didn't
change, it remained just as unclear as it started, and none of the
'somewhere to the left' & 'hand wave' comments were sent to the list.

> This is supported by the following
> points:
> 

I disagree. Many of the responses indicated what they meant by saying
yes, which is not the same as understanding the question. In fact, their
need to explain what question they were answering is an implicit
statement of lack of clarity in the question. 

>        action fails to match their expectations.

Why would there be? They all have their own interpretations, so there
won't be objections until the actual next steps begin. 

> invalidate the consensus.

You missed the point that many of those responses are for an
architectural change that is not in the IETF's purview to decide. See
above.

> that IPv6 site-local unicast addressing should be deprecated. 

No, some of them believed this is about removing local scoped addresses
from the architecture, or consideration by applications. That is not the
same as 'usage' of a defined prefix.

> They may disagree on what we should do after deprecating 
> site- local addressing, but that does not invalidate the 
> consensus on this point.

There is a vast and architectural difference between removing addresses
which are only reachable over a limited part of the network, and usage
of a specific prefix to identify those.  You keep claiming there is a
consensus, but any objective observer of the SF video would disagree.

> 
> ---
> 
> Point (4):
> 
> It is true that the IPv6 WG has not produced a WG document 
> that analyzes the operational requirements for local 
> addressing.  However, we do not believe that this is a reason 
> to invalidate the IPv6 WG consensus to deprecate IPv6 
> site-local unicast addressing.

You said it multiple times in SF yourself, the WG needs complete
documentation to do an appropriate analysis. You appear to be letting
your desire to 'be right' get in the way of your ability to analyze your
own responses. I don't understand how can you objectively say 'we don't
need a document describing the need for X to decide that we don't need
X'?

> also been several drafts published on the subject, including 
> one draft that attempts to analyze the cost/benefit 
> trade-offs of site-local addressing.

There have been personal drafts. The WG has not taken this on as a
specific work item. 

> 
> This period of discussion has offered sufficient time for 
> anyone who has an operational need for any of the 
> currently-defined usage models of site-local addressing to 
> document those requirements in an Internet-Draft and/or to 
> discuss those requirements on the IPv6 mailing list.

They have been discussed on the mail list to the point that people stop
paying attention. This argument is disingenuous because there has never
been a WG item about creating this document. In addition, I have offered
a draft on the subject multiple times in the last month, yet have not
even received as much as a simple 'no thanks' from the chairs.

> 
> During our discussions, several operational benefits of 
> site-local addressing have been raised on the IPv6 WG mailing 
> list, including benefits for disconnected sites, 
> intermittently- connected sites, renumbered sites, etc.  We 
> have also uncovered several issues and complexities caused by 
> the current model of ambiguous, scoped site-local addressing, 
> and we have determined that this particular model places 
> burdens on other parts of the TCP/IP protocol suite, 
> particularly routing protocols and applications.

Most of those difficulties will persist, because they are the result of
inconsistent views of the network topology. There is nothing about
deprecating SL that will change this. The only affect will be to make it
harder to figure out when the burdens exist.

> 
> In a recent phone discussion and in your appeal 
> clarification, you have indicated that the chairs should void 
> responses from people who do not think that the IPv6 WG 
> should specify any type of local addressing mechanism, 
> because you believe that those responders are uninformed 
> about the operational conditions that require the use of 
> local addressing.
> 
> While operational necessity is certainly an appropriate 
> argument to raise in support of your position that the IPv6 
> WG should specify some mechanism for local addressing, the 
> fact that you disagree with the reasons that some people 
> offered for why they want to deprecate the current IPv6 
> site-local unicast addressing mechanism does not invalidate 
> their contribution to this consensus call.

I am pointing out that their 'reason' is not in the purview of the IETF
to decide, so their YES votes are not informed or valid. I am not
objecting to their opinion, just the chair's interpretation of consensus
is in error because it fails to discount the votes for an architectural
point that is out of the IETF's control. 

> whether or not to deprecate IPv6 site-local unicast addressing.

Even though a long-term member of the WG said right before the question
that he did not have enough information to vote NO ...  and another
participant stated he had never heard the requirements before Erik gave
a verbal partial list. How do these create 'an informed decision'?

> 
> ---
> 
> So, to summarize, the chairs do not agree with the points 
> that you have raised in your appeal, and we do not agree to 
> overturn the consensus of the IPv6 WG based on the issues 
> that you have raised.

I am not surprised. 

> issue, we do respect your contributions to the IPv6 effort 
> and we realize that your appeal is motivated by your desire 
> to do the right thing for IPv6.  We hope that you will accept 
> our response to your appeal and focus on working to define 
> the local addressing problem and solutions as we outlined in 
> our email to the list. We think it is important for the 
> working group to move forward on this issue.

I will be escalating to Erik & Thomas, because I do believe that is the
right and expeditious thing to do in this case. 

Tony

---

From: "Tony Hain" <[email-masked]>
Date: Mon, 28 Apr 2003 18:43:47 -0700

Thomas & Erik,

I trust that you will take a more objective view of this, because any
outsider who needs to watch that video will be rolling in the isles with
laughter at the absurdity of the process abuse in this case. At least 5
long-time IETF participants (including yourself) felt the need to state
what they meant by 'deprecate SL'. One has to assume they bothered to
assert their interpretation because the YES/NO question was unclear to
them, or that their need to explain which question they were answering
is an implicit statement that the original question was unclear. Even
though the question never changed, none of the (amazingly vague)
clarifying remarks in SF were sent to the list version of the consensus
call.

If a legal professional were to watch the proceedings here, they would
comment that the WG gave the chairs the freedom to interpret the meaning
of the question any way they choose. In fact we have examples of that
already on the mail list and in this response. 
3/30 chair email claimed
> As part of deprecating site-local addressing, we 
> agreed in the meeting that, in addition to  deprecating 
> site-local addressing in the addressing architecture 
> and removing it from other  places (scoped addressing 
> architecture, address selection rules, etc.), a document 
> would be  written that would do two things:
>
>         - Explain why site-local addressing was deprecated
>         - Outline alternative means to address some of the
>                 problems that could have been solved by
>                 site-local addressing.

That question was never asked of the room, and those statements were not
made by the chairs in SF. How could there be an agreement?

> The decision to deprecate site-local addressing, 
> rather than simply removing it, was made to avoid 
> harm to IPv6.

There was nothing more to this than vague conversations between Margaret
& Keith, and Margaret & Thomas. There was no decision by the WG, just a
chair proclamation that one had occurred. We can't allow the WG process
to degenerate to the point that a chair can call an ambiguous YES/NO
question, then make up anything they choose to have it mean later. In
particular, when the chair explicitly states '... if we eliminate it we
will also have multiple choices about what exactly that means ...', and
'... may have to hand wave ...' there is not a clear indication about
what question is being asked. 

I put specific rebuttal comments to the chair's rejection in a list
response to the chairs. In summary I believe the chairs have declared a
consensus when there really wasn't one due to the ambiguity of the
question. Specifically the YES votes for removing addresses with local
scope from the architecture or consideration by applications are void,
as that is not something the IETF gets to decide. Had the chairs asked
Keith's original question about finding an alternate way forward through
replacement technologies, we would not be going through this process. 

As for a path forward, I would expect you to invalidate the consensus,
then have the WG stop the pronouncements that SL is dead, and work on
finding appropriate replacements. This effort must begin with
identification of the requirements for addresses of local scope, and
under local network manager control. With requirements in hand, the
scoped address architecture document needs to specifically deal with
handling mixed scope addresses, both between and for simultaneous use on
a singe node. That document in particular is hopelessly gutted and
meaningless without such a discussion. IF we get to the point were all
requirements are met by alternatives, the current SL definition should
appropriately be moved to historic. If not, it will likely end up in the
corner case use that Keith was trying to achieve. Either way, the entire
WG must decide exactly what happens. We must not allow the 'ambiguous
YES/NO question - chairs subsequently decide what it means', process to
set a precedent.

Tony

Margaret Wasserman wrote:
> Hi Tony,
> 
> We have considered your appeal regarding the IPv6 WG 
> consensus to deprecate site-locals.  Based on our analysis, 
> we believe that your appeal makes the following points:
> 
> addressing instead of simply removing it. This was done 
> particularly on the IPv6 scoped addressing architecture.  The