Re: [re-ECN] Revised agenda theory

[Leslie Daigle <[e-mail]>]

Hi Bob,

I do take your point about viability (of mechanisms for congestion 
exposure, btw, not re-ECN specifically) being a challenge, but I also 
don't think we'll get to discussing chartering a working group if we 
don't take a whack at it.  "Focus" will be the watch-word.

I'm happy to discuss how to make sure that discussion _is_ focused.  I 
actually think your smiley-table (mail to Fred) is a reasonable starting 
point for at least some aspect of illustrating this.

I should also say -- I don't think the BoF can determine that congestion 
exposure is The One True Way to better Internet health.  I'm not even 
particularly convinced a WG can do that.  I'm hoping the bar is set at 
demonstrating that it is a useful and important step to pursue, even as 
others are pursue elsewhere.

A few more points, in-line:

Bob Briscoe wrote:
> Leslie,
> 
> This looks good, but see below about the viability item, wherein lie 
> monsters. Also, a couple of thoughts before that:
> 
> 1/ I've been thinking... We should add an item to the many purposes list:
> - evolution path beyond TCP (running out of dynamic range)

Which is pretty cool, but on the bof agenda might lead to some ratholing 
on whether we're just bashing TCP, no?

> 
> 2/ I think it would be cool to have a brief session on the community 
> around this; what people are doing in this space, why, etc. This could 
> be structured:
> - either as one of the chairs reporting all this (requiring people to 
> have told you in advance what they're doing - plus scraping the list 
> archive for what people said when they introduced their interest recently),
> - or as a vox pop.
> 
> It would also be a chance to report on some of the activity that has 
> been going on to ensure the commercial & public policy community would 
> be happy with such a change to the Internet (e.g. the GIIC thing you 
> went to, and any ISOC activities you're planning).

I'm happy to have _a_ slide pointing out there's a lot of stuff going on 
in the world, because, as you note, it does communicate that this is 
getting broad airtime in the world at large.  But for the purpose of the 
BoF, I think the major emphasis should be on making sure the people in 
the room have enough information to determine whether they think there 
is an IETF activity here.

The latter is the theory behind "the problem" item on the agenda.  If 
there's a better way to handle that piece of it, happy to take sugestions.

And, I'll be sure to announce the ISOC activity here, when it's, errr, 
announced. :)

> 
> 3/ On the "discussion of viability" it occurs to me that the BoF can't 
> really discuss how viable it might be to deploy re-ECN without also 
> considering the viability of alternative approaches to solve each of the 
> problems we claim to be able to solve (or even whether alternatives exist).
> 
> How otherwise are we going to
> - side-step the net neutrality problem?
> - simplify inter-domain e2e QoS?
> - move beyond TCP which is running out of dynamic range?
> - and so on?
> 
> Taking evolution beyond TCP as an example...
> 
> In the IRTF ICCRG, Matt Mathis has proposed that moving to 1/p 
> congestion controls (rather than 1/sqrt(p) like TCP) would allow 
> congestion control to scale indefinitely, by maintaining a high 
> congestion information rate as flow rates & link rates scale. Whereas if 
> we stick with TCP-friendly, the information rate per window is already 
> becoming stupidly low (hours between loss signals) as rates increase 
> over the next few years. To put it bluntly, as carriers deploy more 
> capacity, we'll be held back by the e2e protocols, which aren't able to 
> use it.
> 
> Widespread re-ECN deployment would allow us to relax the TCP-friendly 
> requirement, so we can bless 1/p controls and shift onto a sounder 
> evolution path.
> 
> The alternative seems to be changing every router (and every LSR and 
> every ethernet switch) in the Internet to do RCP (which still aims for 
> flow-rate-fairness so it still drives ISPs into net neutrality issues, 
> yada yada).
> 
> ____
> Do you see my point about trying to talk about the viability of re-ECN 
> in isolation from wider debate on the viability of the alternatives? But 
> such a session would require a lot of cluefulness in the audience to 
> understand it. You might recall the p2pi workshop, which covered just a 
> small part of this space. It was a selected set of participants, but 
> even then the cluefulness factor from each specialist about a each 
> related area was painfully low.
> 
> I'm not saying we shouldn't try to talk about viability, but it will be 
> a complicated session to do justice to the debate.

And, the sad reality is, we will not do it justice.  What we need to do 
is hit the high points to illustrate that there is viability here, and 
it's worth chartering an IETF activity to delve into it in more depth.

One refinement to the agenda text occurs to me:

CONEX
   5 mins  administrivia
   5 mins  introduction by chairs
Background
  40 mins  the problem
              context/motivation [Rich Woundy]
              technical problem [Mark Handley]
  10 mins  constraints  [Philip Eardley]
  30 mins  towards a solution
              overview of re-ECN   [Bob Briscoe]
Discussion of potential IETF work
  40 mins  discussion of viability of congestion exposure
  20 mins  draft charter discussion
  10 mins  questions and hums


Leslie.

> 
> 
> Bob
> 
> At 04:03 24/10/2009, Leslie Daigle wrote:
> 
>> Hi,
>>
>> We need to get an agenda posted.  Subject to suggested changes, and/or 
>> absent howls of dissent, we'll post the following. Note that I have 
>> expanded it to allow more discussion of the specific viability of the 
>> approach.
>>
>> We'll work on framing up some discussion for that part of the agenda 
>> during the next week, or so.
>>
>> Leslie.
>>
>>
>>
>> Congestion Exposure (ConEx) is a proposed new IETF activity to enable
>> congestion to be exposed along the forwarding path of the Internet. By
>> revealing expected congestion in the IP header of every packet,
>> congestion exposure provides a generic network capability which allows
>> greater freedom over how capacity is shared. Such information could be
>> used for many purposes, including congestion policing, accountability
>> and inter-domain SLAs. It may also open new approaches to QoS and
>> traffic engineering.
>>
>> The purpose of the BoF is to explore the support for and viability of
>> pursuing an IETF activity to define a basic protocol to expose the
>> expected rest-of-path congestion in the IP header. Any such protocol
>> should work with minimal changes to the existing network, in particular
>> it should work with unmodified routers. There is already one existing
>> proposal that builds on ECN to provide rest-of-path congestion
>> information in every IP header and other proposals may come forward.
>>
>> More detail is available at:
>> http://trac.tools.ietf.org/area/tsv/trac/wiki/re-ECN
>>
>> BoF Co-Chairs:
>>
>> Leslie Daigle <[e-mail]>
>> Philip Eardley <[e-mail]>
>>
>>
>> Agenda
>>
>>  5 mins  administrivia
>>  5 mins  introduction by chairs
>> 40 mins  the problem
>>             context/motivation [Rich Woundy]
>>             technical problem [Mark Handley]
>> 10 mins  constraints  [Philip Eardley]
>> 30 mins  towards a solution
>>             overview of re-ECN   [Bob Briscoe]
>> 40 mins  discussion of viability
>> 20 mins  draft charter discussion
>> 10 mins  questions and hums
>>
>>
>> N.B.:  This assumes our current 160min agenda space (check my math!). 
>> If the BoF moves, we'll have to re-think.
>>
>>
>> -- 
>>
>> -------------------------------------------------------------------
>> "Reality:
>>      Yours to discover."
>>                                 -- ThinkingCat
>> Leslie Daigle
>> [e-mail]
>> -------------------------------------------------------------------
>> _______________________________________________
>> re-ECN mailing list
>> [e-mail]
>> https://www.ietf.org/mailman/listinfo/re-ecn
> 
> ________________________________________________________________
> Bob Briscoe,                                BT Innovate & Design

-- 

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"Reality:
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Leslie Daigle
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