[e2e] Congestion control as a hot topic in IETF

Jon Crowcroft Jon.Crowcroft at cl.cam.ac.uk
Wed Mar 6 15:29:27 PST 2013

well I beg to differ about this work being about
a "congestion control free" internet

the decongestion control idea involves (as well as xor coding)
a) fairness support at the edges of the net (under specified)
b) active queue management in the core (a decent implemenation
would need the same sort of virtual queue mechanisms a lot of
decent ECN implemenations have looked at)

so while the work is cool (for sure) and I am definitely in favour
of exploring the design space, it doesn't amount really to 
just "everyone send as fast as they can" at all - that doesn't seem
a fair way to describe it

so i'd claim it is still congestion control, just with a different
partitioning of the functionality than a purist end2end (which is
just fine - i am no purist:)

there is also the long term argument that the ratio of core to edge capacity
flips over every now and then -- see the figure in our paper
and this makes a lot of things break badly (go to places where the
core nets are massively under provisioned and you'll see what
damage "just a little bit of packet loss" can do...

In missive <51377F9F.1080206 at isae.fr>, Emmanuel Lochin typed:

 >>Hi all,
 >>We've attempted with success to implement a Decongestion Control 
 >>Transport Protocol following A. Snoeren and T. Bonald Infocom'09 paper : 
 >>"Is the law of Jungle sustainable for the Internet". We defined an 
 >>"Anarchical Networks" scenario and tested our proposal named DCTP with 
 >>Achoo (proposed by A. Snoeren) over a simulated ISP-like topology.
 >>Preliminary results tend to confirm that both Snoeren and Bonald are 
 >>right and that such architecture is sustainable.
 >>You'll find our first experiments in the slides available here: 
 >>On 05/03/2013 13:07, Scharf, Michael (Michael) wrote:
 >>>> Am 04.03.2013 23:07, schrieb Scharf, Michael (Michael):
 >>>>> There has been some interesting research on whether a
 >>>> transport protocol could work without any congestion control.
 >>>> One reference is: B. Raghavan and A. Snoeren, "Decongestion
 >>>> Control", ACM SIGCOMM Workshop on Hot Topics in Networks, 2006.
 >>>> I remember that you, some years ago, asked whether networking
 >>>> can be done without flow control.
 >>> My comment is about network designs that typically assume erasure codes and flow-based queueing/scheduling in all network nodes. Actually, it took me a while to fully understand why this is no alternative to the way Internet congestion control works today. But, for what it is worth, I found the overall idea intesting.
 >>> Michael
 >>Emmanuel Lochin
 >>Professeur ISAE - OSSI
 >>Institut Supérieur de l'Aéronautique et de l'Espace (ISAE)
 >>Issu du rapprochement SUPAERO et ENSICA
 >>10 avenue Edouard Belin - BP 54032 - 31055 Toulouse cedex 4
 >>Tel : 05 61 33 91 85 - Fax : 05 61 33 91 88
 >>Web : http://personnel.isae.fr/emmanuel-lochin/
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