Internet Engineering Task Force P. Resnick
Internet-Draft Qualcomm Technologies, Inc.
Intended status: Informational February 13, 2013
Expires: August 17, 2013
On Consensus and Humming in the IETF
draft-resnick-on-consensus-01
Abstract
The IETF has had a long tradition of doing its technical work through
a consensus process, taking into account the different views among
IETF participants and coming to (at least rough) consensus on
technical matters. In particular, the IETF is supposed not to be run
by a "majority rules" philosophy. This is why we engage in rituals
like "humming" instead of voting. However, more and more of our
actions are now indistinguishable from voting, and quite often we are
letting the majority win the day. This document is a collection of
thoughts on what rough consensus is, how we have gotten away from it,
and the things we can do in order to really achieve rough consensus.
Note: This document contains the musings of an individual. Right
now, it is just some rough notes and has lots of holes that need
to be filled in. Even if those holes are filled, in its current
form, it is not intended to be published as an RFC, let alone
being a BCP for a change of IETF policy. If it evolves into such
a thing, great. If it simply sparks discussion as an Internet
Draft, that's a perfectly fine outcome.
Status of This Memo
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This Internet-Draft will expire on August 17, 2013.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Lack of disagreement is more important than agreement . . . . 3
3. Rough consensus is when all issues are addressed, but not
necessarily accommodated . . . . . . . . . . . . . . . . . . 4
4. Humming is the start of a conversation, not the end . . . . . 6
5. One Hundred people for and five people against might not be
rough consensus . . . . . . . . . . . . . . . . . . . . . . . 8
6. Five people for and one hundred people against might still be
rough consensus . . . . . . . . . . . . . . . . . . . . . . . 8
7. Security Considerations . . . . . . . . . . . . . . . . . . . 10
8. Informative References . . . . . . . . . . . . . . . . . . . 10
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 10
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
Almost every IETF participant knows the aphorism from Dave Clark's
1992 plenary presentation [Clark] regarding how we make decisions in
the IETF:
We reject: kings, presidents and voting.
We believe in: rough consensus and running code.
That is, we don't let a single individual make the decisions, nor do
we let the majority dictate decisions, nor do we allow decisions to
be made in a vacuum without practical experience. Instead, decisions
are made by (more or less) consent of all participants, and the
actual products of engineering trump theoretical designs. We don't
require full consensus; that would allow a single intransigent person
who simply keeps saying "No!" to stop the process cold. We only
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require rough consensus: If the chair of a working group determines
that a technical issue brought forward by an objector has been truly
considered by the working group, and the working group has made an
informed decision that the objection has been answered or is not
enough of a technical problem to move forward, the chair can declare
that there is rough consensus to move forward, the objection
notwithstanding. To reinforce that we do not vote, we have also
adopted the tradition of "humming": When (for example) the chair of
the working group wants to get a "sense of the room", instead of a
show of hands, the chair asks for each side to hum for or against a
question.
However, in recent years we have seen participants (including folks
in IETF leadership) who do not understand some of the subtleties of
consensus-based decision making. Participants ask, "Why are we
bothering with this 'humming' thing? Wouldn't a show of hands be
easier? That way we could really see how many people want one thing
over another." Chairs are faced with factious working groups with
polarized viewpoints and long-running unresolved issues that return
again and again to the agenda. More and more frequently, people walk
away from working groups, thinking that "consensus" has created a
document with horrible compromises to satisfy everyone's pet peeve
instead of doing "the right thing". None of these things are
indicators of a rough consensus process being used, and are likely
due to some basic misperceptions.
This document attempts to explain some features of rough consensus,
explain what is not rough consensus, and suggest ways that we might
achieve rough consensus and judge it in the IETF.
Note: This document contains the musings of an individual. Right
now, it is just some rough notes and has lots of holes that need
to be filled in. Even if those holes are filled, in its current
form, it is not intended to be published as an RFC, let alone
being a BCP for a change of IETF policy. If it evolves into such
a thing, great. If it simply sparks discussion as an Internet
Draft, that's a perfectly fine outcome.
2. Lack of disagreement is more important than agreement
A working group comes to a technical question of whether to use
format A or format B for a particular data structure. The chair
notices that a number of experienced people think format A is a good
choice. The chair asks on the mailing, "Is everyone OK with format
A?" Inevitably, a number of people object to format A for one or
another technical reason. The chair then says, "It sounds like we
don't have consensus to use format A. Is everyone OK with format B?"
This time even more people object to format B, on different technical
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grounds. The chair, not having agreement on either format A or
format B, is left perplexed, thinking the working group has
deadlocked.
The problem that the chair got into in the above case was to think
that what they were searching for was agreement. "After all", thinks
the chair, "consensus is a matter of getting everyone to agree, so
asking whether everyone agrees is what the chair ought to do. And if
lots of people disagree, there's no consensus." But _determining_
consensus and _coming to_ consensus are different things than
_having_ consensus. Consensus is not when everyone is happy and
agrees that the chosen solution is the best one. Consensus is when
everyone is satisfied enough with the chosen solution that they do
not object to it. The distinction might be a bit subtle, but it's
important. Engineering always involves a set of tradeoffs. It is
almost certain that any time engineering choices need to be made,
there will be options that appeal to some people that are not
appealing to some others. The key is to separate those choices that
are simply unappealing from those that are truly problematic. [[:
Example:Insert catchy example here.]] So in the case of a working
group decision, it is most important to ask not just for objections
to a particular proposal, but for the nature of those objections. A
chair who asks, "Is everyone OK with choice A?" is going to get
objections. But a chair who asks, "Can anyone not live with choice
A?" is more likely to only hear from folks who think that choice A
is impossible to engineer given some constraints. Then the purported
failings of the choice can be examined by the working group. The
objector can convince the rest of the group that the objections are
valid, or the working group might convince the objector that the
concerns can be addressed, or that the choice is simply unappealing
(i.e., something the objector can "live with") and not a show-
stopper. In any event, closure is much more likely to be achieved
quickly by asking for and trying to accomodate the objections rather
than asking for agreement.
This also brings up an important point about reaching consensus:
Consensus does not really involve compromising. "Compromising"
implies that there remains something wrong with the outcome, but that
the objector has simply given up. That is not coming to consensus.
To truly come to consensus does not involve making a compromise, but
rather coming to the conclusion that either the objection is valid
(and therefore making a change the address the objection), or
concluding that the objection was not really a matter of importance,
but merely a matter of taste. Of course, coming to full consensus
does not always happen.
3. Rough consensus is when all issues are addressed, but not
necessarily accommodated
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The preceding discussion gives an example where the working group
comes to consensus on a point: Either the objector is satisfied, or
the working group is satisfied. But certainly that doesn't happen
all of the time, and it's certainly not the problematic case.
Engineering is always a set of tradeoffs. Often, a working group
will encounter an objection where everyone understands the issue,
acknowledges that it is a real shortcoming in the proposed solution,
but the vast majority of the working group believe that accommodating
the objection is not worth the tradeoff of fixing the problem. So,
an objector might say, "The proposal to go with protocol X is much
more complicated than going with protocol Y. Protocol Y is a much
more elegant and clean solution, and protocol X is a hack." The
working group might consider this input, and someone might respond,
"But we have a great deal of code already written that is similar to
protocol X. While I agree that protocol Y is more elegant, the risks
to interoperability with an untested solution is not worth it
compared to the advantages of going with the well-understood protocol
X." If the chair finds, in their technical judgement, that the issue
has truly been considered, and that the vast majority of the working
group has come to the conclusion that the tradeoff is worth making,
even in the face of continued objection from the person(s) who raised
the issue, the chair can declare that the group has come to rough
consensus.
Now, a conclusion of only rough consensus relies heavily on the good
judgement of the consensus caller. The group must truly consider and
weigh an issue before the objection can be dismissed as being "in the
rough". The chair of the working group in one of these cases is
going to have to decide that not only has the working group taken the
objection seriously, but that it has fully examined the ramifications
of not making a change to accommodate it, and that the outcome does
constitute a failure to meet the technical requirements of the work.
In order to do this, the chair will need to have a good idea of the
purpose and architecture of the work being done and use their own
technical judgement to make sure that the solution meets those
requirements. What can't happen is that the chair bases their
decision solely on hearing a large number of voices simply saying,
"The objection isn't valid." That would simply be to take a vote. A
valid justification needs to me made.
Any finding of rough consensus needs at some level to be a
satisfactory explanation to the person(s) raising the issue of why
their concern is not going to be dealt with. A good outcome is for
the objector to be satisfied that, although their issue is not being
accommodated in the final product, they understand and accept the
outcome. Remember, if the objector feels that the issue is so
essential that it must be attended to, they always have the option to
file an appeal. A technical error is always a valid basis for an
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appeal, and a chair or AD has the freedom and the responsibility to
say, "The group did not take this technical issue into proper
account." Simply having a number of people agreeing to dismiss an
objection is not enough.
4. Humming is the start of a conversation, not the end
We don't vote in the IETF. In some ways, we can't vote: Since the
IETF is not a membership organization, it's nearly impossible to
figure out who would get a vote for any given question. We don't
know who the members of any given working group are at any one time,
and we certainly don't know who all of the members of the IETF are.
So voting is not practical. We've also decided that coming to
consensus (albeit sometimes rough consensus) is an important thing to
do. So instead of voting, we "hum".
However, more and more we see people who think that a hum is a sort
of anonymous vote, with some chairs calling every question they have
for the working group by asking for a hum and judging the result by
the loudest hum, even saying things like, "There were lots of hums
for choice 1 and very few hums for choice 2, so it sounds like we
have rough consensus for choice 1." This really misses the point of
humming and is almost certainly mis-assessing the consensus. Hums
should not be used as votes.
So, why do we hum? The first reason is pragmatic. Quite often, a
chair is faced with a room full of people who seem to be
diametrically opposed on some choice facing the group. In order to
find a starting place for the conversation, it is often useful for
the chair to ask for a hum to see if one of the choices already has a
stronger base of support than the other. If choice "foo" has a
significant amount more support than choice "bar", it is likely
easier to start the discussion by saying, "OK, 'foo' seems to have
quite a bit of support. Let's have the people that think 'foo' is a
bad idea come up and tell us why it is problematic." At that point,
the group can start going through the issues and see if any of them
are showstoppers. It may turn out that one of the objections is
instantly recognized by the entire group as a fatal flaw in "foo" and
the group will then turn to a discussion of the merits (and demerits)
of "bar" instead. All that the hum does is give the chair a starting
point: There were likely to be less objections to "foo" than to "bar"
at the beginning of the discussion, so starting with whatever got the
most hums can shorten the discussion.
But couldn't the above could have been done with a show of hands
instead of a hum? Sure, but there are more formal reasons for using
a hum instead of a show of hands. Another reason we hum is because
it actually gives the chair the opportunity to take the temperature
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of the room. A smaller bunch of loud hums for choice A and a larger
number of non-committal hums for choice B might indicate that some
people believe that there are serious problems with choice B, albeit
the more popular by sheer number of people. The chair might decide
that starting with choice A and getting objections to it is the
easier path forward and more likely to result in consensus in the
end. Remember, coming to consensus is a matter of eliminating
disagreements, so the chair wants to choose the path that gets to the
least objections fastest. A bunch of people who are not strongly
committed to B might have no real technical objection to A, even
though it is not their first preference. Taking the hum is to figure
out how to start the conversation. Unless, to the chair's surprise,
the hum is unanimous, the hum begins the discussion; it doesn't end
it. Of course, a chair could get the temperature of the room by
doing a show of hands, and knowing who specifically feels one way or
another can help a good chair guide the subsequent conversation.
However, a show of hands will often leave the impression that the
number of people matters in some formal way. It takes a chair and a
working group with a solid understanding of how consensus works to do
a show of hands and not end up reinforcing the mistaken notion that a
vote is taking place. A chair can always take the hum and then later
ask for specific folks to identify themselves to elicit more
discussion. The hum makes it perfectly clear that the chair is
simply figuring out the direction of the conversation.
This also points to another misuse of the hum: If the chair is
already convinced that the group has come to consensus, there is no
reason to take a hum. In fact, taking the hum only serves to
discourage those who might be in the minority from voicing their
concerns to the group in the face of a large majority who want to
move forward. The right thing for the chair to do if they already
sense consensus is to say, "It sounds to me like we have consensus
for choice A. Does anybody have any concerns or objections to going
with A?" This allows folks to bring up issues to the group that the
chair might have mistakenly missed without having them feel that the
majority has "already spoken".
There are times where the result of a hum is a pretty even split. In
practical terms, that means it doesn't matter where the chair starts
the discussion. And in fact, we've had working groups where a coin-
flip decided which proposal to start with. That doesn't mean that
the coin-flip determined the outcome; if a fatal technical flaw was
found in the chosen solution, it is still incumbent upon the group to
address the issue raised. Rough consensus on the technical points,
in the end, is always required. Any way to find a place to start, be
it the hum or the coin-flip, is only getting to the beginning of the
discussion, not the end.
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5. One Hundred people for and five people against might not be rough
consensus
Remember that consensus is found when all of the objections have been
addressed. Because of this, using rough consensus avoids a major
pitfall of a straight vote: If there is a minority of folks who have
a valid technical objection, that objection must be dealt with before
consensus can be declared. This also reveals one of the great
strengths of using consensus over voting: It isn't possible to use
"vote stuffing" (simply recruiting a large number of people to
support a particular side, even people who have never participated in
a working group or the IETF at all) to change the outcome of a
consensus call. As long as the chair is looking for outstanding
technical objections and not counting heads, vote stuffing shouldn't
affect the outcome of the consensus call. So in a large working
group with over 100 active participants and broad agreement to go
forward with a particular protocol, if a few participants say, "This
protocol is going to cause congestion on the network, and it has no
mechanism to back off when congestion occurs; we object to going
forward without such a mechanism in place", and the objection is met
with silence on the mailing list, there is no consensus. Even if the
working group chair makes a working group last call on the document,
and 100 people actively reply and say, "This document is ready to go
forward", if the open issue hasn't been addressed, there's still no
consensus. It's the existence of the unaddressed open issue, not the
number of people, which is determinative in judging consensus. As
discussed earlier, you can have rough consensus with issues that have
been purposely dismissed, but not ones that have been ignored.
6. Five people for and one hundred people against might still be rough
consensus
This one is the real mind bender for most people, and certainly the
most controversial. Say there is a very small working group, one
with half a dozen truly active participants who are experts in the
field; everybody else is just following along, but not contributing
to the discussion. The active folks come up with a protocol document
that they all agree is the right way forward, and people inside and
outside the working group agree that the protocol is likely to get
widespread adoption; it is a good solution to a real problem, even if
the non-experts don't have the ability to fully judge the details.
However, one of the active members has an objection to a particular
section: The protocol currently uses a well-known algorithm to
address an issue, but the objector has a very elegant algorithm to
address the issue, one which works especially well on their
particular piece of hardware. There is some discussion, and all of
the other contributors say, "Yes, that is elegant, but what we're
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using now is well-understood, widely-implemented, and it works
perfectly acceptably, even on the objectors hardware. There is
always some inherent risk to go with a new, albeit more elegant,
algorithm. We should stick to the one we've got." The chair follows
the conversation and says, "It sounds like the issue has been
addressed and there's consensus to stick with the current solution."
The objector is not satisfied, maybe even saying, "But this is silly.
You've seen that my algorithm works. We should go with that." The
chair makes the judgement that the consensus is rough, in that there
is still an objector, but the issue has been addressed and the risk
argument has won the day. The chair makes a working group last call.
Now the worst case scenario happens. The objector, still unhappy
that their preferred solution was not chosen, recruits one hundred
people, maybe a few who were silent participants in the working group
already, but mostly people who are at the same company as the
objector who never participated before. The objector gets them all
to post a message to the list saying, "I believe we should go with
the new elegant algorithm in section 5.6 instead of the current one.
It is more elegant, and works better on our hardware." The chair
sees these dozens of messages coming in and posts a query to each of
them: "We discussed this on the list, and we seemed to have consensus
that, given the inherent risk of a new algorithm, and the widespread
deployment of this current one, it's better to stick with the current
one. Do you have further information that indicates something
different?" And in reply the chair gets utter silence. These
posters to the list (say some of whom were from the company sales and
marketing department) thought that they were simply voting and have
no answer to give. At that point, it is within bounds for the chair
to say, "We have objections, but the objections have been
sufficiently answered, and the objectors seem uninterested in
participating in the discussion. Albeit rough in the extreme, there
is rough consensus to go with the current solution."
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There is no doubt that this is the degenerate case and a clear
indication of something pathological. But this is precisely what
rough consensus is designed to guard against: vote stuffing. In the
presence of an objection, the chair can use their technical judgement
to decide that the objection has been answered by the group and that
rough consensus overrides the objection. Now, the case described
here is probably the hardest call for the chair to make (how many of
us are willing to make the call that the vast majority of people in
the room are simply stonewalling, not trying to come to consensus?),
and if appealed it would be incredibly difficult for the appeals body
to sort it out. Indeed, it is likely that if a working group got
this dysfunctional, it would put the whole concept of coming to rough
consensus at risk. But still, the correct outcome in this case is to
look at the very weak signal against the huge background noise in
order to find the rough consensus.
7. Security Considerations
"He who defends with love will be secure." -- Lao Tzu
8. Informative References
[Clark] Clark, D. D., "A Cloudy Crystal Ball - Visions of the
Future", July 1992.
In
[IETF24] Davies, M., Ed., Clark, C., Ed., and D. Legare, Ed.,
"Proceedings of the Twenty-Fourth Internet Engineering
Task Force", July 1992,
<http://www.ietf.org/proceedings/24.pdf>.
[Sheeran] Sheeran, M. J., "Beyond Majority Rule: Voteless Decisions
in the Religious Society of Friends", December 1983.
Appendix A. Acknowledgements
This document is the result of conversations with many IETF
participants, too many to name individually. I greatly appreciate
all of the discussions and guidance. I do want to extend special
thanks to Peter Saint-Andre, who sat me down and pushed me to start
writing, and to Melinda Shore for pointing me to Beyond Majority Rule
[Sheeran], which inspired some of the thinking in this document.
Author's Address
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Pete Resnick
Qualcomm Technologies, Inc.
5775 Morehouse Drive
San Diego, CA 92121
US
Phone: +1 858 6511 4478
Email: presnick@qti.qualcomm.com
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