[Iccrg] Why don't we stop treating ECN and loss similarly?

[Mikael Abrahamsson]

On Mon, 29 Oct 2012, Michael Welzl wrote:

> Perhaps some of the ideas for reacting to a finer-grain ECN signal will 
> lead to an answer to that.

As far as I can tell, ECN has decent end-system support, but very limited 
network support. I don't know of any major core routing platform that 
supports setting ECN in a RED configuration instead of dropping the 
packet (last I checked this was 1.5 years ago, but talking to vendors 
indicated very little interest).

I'm also seeing buffer depth going down over time (see bufferbloat 
discussion, plus prolifiration of L3 switches with minimal onboard buffers 
instead of larger classical router ones), which means that it's even 
harder than before to justify ECN as nothing in a live network will really 
act on ECN being used or not by the end system. If someone else has other 
information, I'd like to know.

Perhaps it would be valuable to write some text about the state of ECN 
support right now, and then a plan to increase value for ECN so we can get 
it adopted. Current state of affairs is that few care about ECN because 
nobody is asking for it (same as with IPv6), so there is little commercial 
incentive to get it implemented. I feel most talk about ECN is from 
academia with little current real world implications. I'd like to see this 
changed, but I don't really know how. Changing the standards to 
implementing ECN actually brings improvement to both ISP and end user 
might be a good first step towards a world where ECN is actually used.

-- 
Mikael Abrahamsson    email: swmike at swm.pp.se