Subject: [rrg] Form of the final recommendation?

From: Robin Whittle <[email-masked]>
Date: Fri, 25 Dec 2009 14:53:56 +1100

Hi Lixia and Tony,

I don't have a clear idea of what documents the RRG will be producing
or how these will be debated, drafted and finalised.

Here's my current understanding and some questions.

I saw 14 proposals.  However, one is for archival purposes only:

   Enhanced Efficiency of Mapping Distribution Protocols in
   Map-and-Encap Schemes
     http://www.ietf.org/mail-archive/web/rrg/current/msg05540.html
     K. Sriram, Young-Tak Kim, and Doug Montgomery

and three, in my estimation, are only for mapping systems:

   2-phased mapping for Internet core/edge split schemes
     http://www.ietf.org/mail-archive/web/rrg/current/msg05536.html
     Wei Zhang

   Layered Mapping System
     http://www.ietf.org/mail-archive/web/rrg/current/msg05534.html
     http://www.ietf.org/mail-archive/web/rrg/current/msg05554.html
     Sun Letong, YinXia, Wang ZhiLiang, Wu Jianping

   Mapping system based on compact routing
     http://www.ietf.org/mail-archive/web/rrg/current/msg05519.html
     http://www.ietf.org/mail-archive/web/rrg/current/msg05531.html
     Hannu Flinck

Tony wrote:

  http://www.ietf.org/mail-archive/web/rrg/current/msg05496.html

     Mapping systems are obviously a component of a solution but are
     not by themselves a solution. To be considered seriously, they
     should be used in conjunction with some network layer solution.

Are the four proposals above going to be part of the final phase?

The archival one is not really meant to be a solution. The other
three could only be part of a solution, and I think they can't be
evaluated alongside the other 10 proposals because they do not
contain a proposal for a complete solution.   The first one is meant
to apply to various core-edge separation schemes.  The last two seem
to be attempts to improve on ALT, for the purposes of providing a
mapping system for LISP.  However, without the proponents of those
core-edge separation schemes adopting these mapping systems, there's
no way of evaluating how well the combination would work.

I understand from:

  http://www.ietf.org/mail-archive/web/rrg/current/msg05544.html

that you are compiling the summaries into an Internet Draft and that
in that ID each summary will be followed by a 500 word "analysis".

I understand the proponents are to find and choose one or more people
(ideally several: "collaboration of a number of people" to write the
"analysis" - but that the proponents can't write or contribute to
that analysis themselves.   So these analyses will presumably be
reasonably positive - or as positive as the proponents can persuade
anyone to write!

Then there will be a 500 word "rebuttal" of the proposal.  This will
be solicited by Lixia and yourself.  Is this to be written by one
person or more?  Will you ask particular people to write this - or
will you accept contributions from anyone?  How would you choose the
people or between contributed rebuttals?  Is anyone to contribute a
rebuttal to the RRG list, or should we do it in private to the co-chairs?

Is "rebuttal" too strong a term to use?  I guess a critique could
either be in terms that the proposal cannot possibly work - which is
a rebuttal - or that it could work, but not as well as some other
proposal.  That could be tricky to do respectfully (with sufficient
details, arguments and qualifications) in 500 words, since it also
involves evaluating at least one other proposal which would be argued
to work better.

Then you will solicit "another counterpoint".  "Solicit" indicates to
me that you won't simply ask the proponents for a "counterpoint" but
that you will ask someone to write something - or accept potentially
multiple counterpoints and either choose one, or encourage the
authors to work together to produce a single one.

Will people contribute counterpoints freely on the list, or directly
to you?  I guess the counterpoint is to the "rebuttal" - so it can
only be written after the rebuttals are finalised.

Are the proponents allowed to write a counterpoint?  What if the
proponents of the proposal don't like your choices about the
counterpoint?

While it looks tricky, I can see some value in this set of pieces of
writing.

But the resulting document doesn't seem to resemble a
"recommendation" to the IETF.

I guess there will be a lot of debate on the list about the merits of
the various proposals.  However, the remaining 10 proposals are not
all directly comparable.  I think they fit into three groups:

A - 3 core-edge separation proposals which would work for both IPv4
    and IPv6 and not require any host changes:

     Ivip
       http://www.ietf.org/mail-archive/web/rrg/current/msg05533.html
       Robin Whittle

     LISP
       http://www.ietf.org/mail-archive/web/rrg/current/msg05503.html
       Vince Fuller, Dino Farrinacci, David Meyer and Darrel Lewis.

     Tunneled Inter-domain Routing (TIDR)
       http://www.ietf.org/mail-archive/web/rrg/current/msg05538.html
       Juan Jose Adan

    These three seem to be in direct competition in that it would
    only make sense to adopt one, and because they seem to be based
    on broadly the same set of assumptions.  I think each could
    potentially be adopted widely, on a voluntary basis, in a
    not-too-distant time-frame (3 to 10 years), due to there being no
    need for host changes and no assumptions about widespread
    migration to IPv6 as providing relief from the IPv4 scaling
    problem.

B - 6 proposals which I think are all core-edge elimination schemes
    which I think are not suitable for widespread voluntary adoption
    in the near-term, due to the need for host-changes.  Some are
    IPv6-only.  One is IPv4-only - while I recall the RRG consensus
    is to definitely solve the IPv6 problem, and ideally the IPv4
    problem too.

    These seem to me to have different goals, different time-frames
    and very different ideas about adoption than the Group A
    proposals:

     Global Locator, Local Locator, and Identifier Split (GLI-Split)
       http://www.ietf.org/mail-archive/web/rrg/current/msg05537.html
       Michael Menth, Matthias Hartmann and Dominik Klein

     hIPv4
       http://www.ietf.org/mail-archive/web/rrg/current/msg05529.html
       Patrick Frejborg

     Identifier-Locator Network Protocol (ILNP)
       http://www.ietf.org/mail-archive/web/rrg/current/msg05539.html
       Ran Atkinson

     Name-Based Sockets
       http://www.ietf.org/mail-archive/web/rrg/current/msg05543.html
       Christian Vogt

     Name overlay (NOL) service for scalable Internet routing
       http://www.ietf.org/mail-archive/web/rrg/current/msg05532.html
       Yangyang Wang

     RANGI
       http://www.ietf.org/mail-archive/web/rrg/current/msg05505.html
       Xiaohu Xu

C - One proposal which could be adopted without any further IETF
    protocol development and would probably not preclude any other
    proposal.  At the same time, I think few people would see it as a
    full solution to the routing scaling problem - which is what the
    Group A and B proposals are attempting to be.

     Aggregation with Increasing Scopes: An Evolutionary Path Towards
     Global Routing Scalability
       http://www.ietf.org/mail-archive/web/rrg/current/msg05542.html
       Dan Jen, Dan Massey, Robert Raszuk, Lan Wang, Xiaohu Xu,
       Beichuan Zhang and Lixia Zhang.

    This proposal suggests it is near-term preliminary to a
    longer-term host-based solution - implicitly a core-edge
    elimination scheme.  Some of the proponents previously worked
    on a core-edge separation scheme (APT) but decided that this -
    and presumably other such schemes - are too difficult to
    introduce.

Is the RRG's final recommendation going to be in a separate ID from
the one with the summaries, analyses, rebuttals and counterpoints?

If so, what is the schedule for discussing and writing it?

Could the recommendation be split into sections according to
time-frame and/or for IPv4 and IPv6?

There are divergent viewpoints about how important it is to solve the
IPv4 scaling problem and how urgently we need to work on the IPv6
scaling problem.  Maybe the RRG will reach consensus on this and so
be able to recommend a single approach.

If there is no broad consensus or this on anything else, will the
final recommendation try to summarise the two or more major groups of
viewpoints?

Discussion of proposals has been banned or discouraged until now.
Only a subset of the proposals which were discussed on the RRG or the
RAM list are still alive.  Now there are a bunch of new ones - or at
least unfamiliar ones, since TIDR predates this incarnation of the
RRG and has barely been mentioned on the mailing list.

I hope you will be able to help me and others understand the form of
the final recommendation.

  - Robin

---

From: Tony Li <[email-masked]>
Date: Fri, 25 Dec 2009 08:13:41 -0800

Hi Robin,

> Are the four proposals above going to be part of the final phase?

Yes, they can participate.  However, I expect that the critique of these 
proposals will be somewhat pointed.

> reasonably positive - or as positive as the proponents can persuade

No, it is NOT up to the proponents to coordinate the analysis.  It is 
open to the group to do so.  I would expect them to be direct, succinct 
and quite possibly critical.

> rebuttal to the RRG list, or should we do it in private to the co-chairs?

I would expect this to come from the proponents, but that's not a strict 
requirement.  If there are multiple submissions, we reserve the right to 
choose one wholly arbitrarily.  Thus, it is in everyone's interest to 
collaborate if at all possible.

> involves evaluating at least one other proposal which would be argued

It's what we've chosen.  Comparing against another proposal is not the 
intent.  These should be clear debates about the pros and cons of 
individual proposals in isolation.

> authors to work together to produce a single one.

The intent is that this would come from the same folks that wrote the 
analysis.

> only be written after the rebuttals are finalised.

Either mechanism is fine.  Yes, these are necessarily sequential.

> proponents of the proposal don't like your choices about the

It's not very constructive if the proponents interfere in both the pro 
and con sides of the argument.

> "recommendation" to the IETF.

It's not the final step.  This creates the full background.  At the end 
we will have documented each proposal and made arguments pro and con for 
each of them.

> the one with the summaries, analyses, rebuttals and counterpoints?

No, it should be the same document.

> time-frame and/or for IPv4 and IPv6?

That depends entirely on what the recommendation ends up being.

> final recommendation try to summarise the two or more major groups of

We hope for broad consensus.

Tony

---

From: Robin Whittle <[email-masked]>
Date: Sat, 26 Dec 2009 15:31:20 +1100

Hi Tony,

I now understand that all 14 proposals are included, but that you
expect the critique ("analysis", I think) of the 4 proposals I
mentioned first would be "somewhat pointed" - presumably by
mentioning that they are not actually solutions to the routing
scaling problem.

I think the same is true of the last proposal I mentioned, which I
think is a collection of previously documented techniques which may,
at best, marginaly improve the ability of a network to cope with
DFZ routing table growth without buying too many new routers.  This
falls far short of a a proper solution - which will involve the
ability to scalably provide millions or billions of end-user networks
with portability, multihoming and TE.

You wrote:

>> I understand the proponents are to find and choose one or more
>> people (ideally several: "collaboration of a number of people" to
>> write the "analysis" - but that the proponents can't write or
>> contribute to that analysis themselves.   So these analyses will
>> presumably be reasonably positive - or as positive as the
>> proponents can persuade anyone to write!
>
> No, it is NOT up to the proponents to coordinate the analysis.  It
> is open to the group to do so.  I would expect them to be direct,
> succinct and quite possibly critical.

Sorry - my previous message was based on my misunderstanding that the
proponents of each proposal would solicit an analysis for their
proposal.  I also misunderstood the "rebuttal" to be of the proposal,
rather than of the analysis.

> collaborate if at all possible.

OK.  It's not clear how the group is supposed to coordinate these
   analyses.  Who wants to step forward and be one one of the
official party-poopers of a proposal, asking for others to join them?
 (I volunteer to collaborate on critical analyses of LISP and TIDR -
the only two proposals which I think have a hope of being adopted.)

What if no-one cares enough about a proposal to read it
comprehensively and write an analysis?

> individual proposals in isolation.

Since our goal is to choose the best proposal, I don't see how we can
avoid thinking and presumably writing about other proposals.

There are at least two types of "cons":  Firstly, those which make
the proposal untenable or undesirable irrespective of alternatives.
Secondly those where the proposal is perhaps feasible, but another
proposal does something significantly better than this proposal.

With "pros", some advantages of a proposal are unique to the proposal
- which should be mentioned as such.  Other "pros" are significant in
terms of degree - that no other proposal does something so well.
Both types of statement involve negative value judgements about
either all other proposals, or about particular other proposals.
These value judgments need to be made - and they need to be supported
by arguments, which your sentence above does not seem to allow for.

These pros and cons are absolutely central to the final choice of
proposal.

> The intent is that this would come from the same folks that wrote the

OK.

> Either mechanism is fine.  Yes, these are necessarily sequential.

OK - I understand this process for the counterpoints.  I am not clear
how you want people to self-organise the "analysis" stage.  Do you
want draft or final "analyses" to be sent to the list?  I think that
would be a good way to further discussion and prompt other people to
become involved in contributing to a better analysis if they feel
those posted to the list could be improved upon.

For each proposal I understand there will be:

   Summary.            Written by proponents.

   Critical analysis.  Written by self-chosen group members, other
                       than the proponents, who ideally work together
                       on a single piece - otherwise the co-chairs
                       will need to choose between several.

                       Should be critical without any attempt to
                       compare it with other proposals.

                       Deadline 12 January (msg 5558).

   Rebuttal of the above.  Written by proponents.

                       We can start on this after 12 January.

   Counterpoint.       After the rebuttals have been finalised.

                       Could be written by the authors of the
                       critical analysis - or maybe someone else.

                       Counterpoints to be offered on-list or
                       directly to the co-chairs. Co-chairs will
                       chose one if multiple are offered.

> we will have documented each proposal and made arguments pro and con for

Yes, but these will be very constrained in terms of word-count and
you don't want the analysis (critique) to mention other proposals.
Presumably the on-list discussion will make up for these restrictions.

> We hope for broad consensus.

OK - so I think I understand the process for summary, analysis,
rebuttal and counterpoint.

There are no deadlines yet for the final two states of that, and no
guidance yet from you or Lixia on how we will develop a
recommendation before early March.

I understand from:

  http://www.ietf.org/mail-archive/web/rrg/current/msg05558.html

that an ID needs to be submitted by 2010-03-01, but that it can be
updated until 2010-03-08.

 - Robin

---

From: Tony Li <[email-masked]>
Date: Sat, 26 Dec 2009 00:31:42 -0800

Hi Robin,

> the only two proposals which I think have a hope of being adopted.)

Just like that.  ;-)

> comprehensively and write an analysis?

Then that by itself will be an indication.

> avoid thinking and presumably writing about other proposals.

Well, it's your choice as to what you do with your word count.

> those posted to the list could be improved upon.

The final version should be sent to the list.  This will enable rebuttal 
to begin immediately.

> recommendation before early March.

As I think I mentioned previously, we are proposing a deadline every 
three weeks.

Tony