Subject: Re: [tcpm] last version du mail; dernière relecture

From: Renaud Sallantin <[email-masked]>
Date: Fri, 20 Dec 2013 18:22:58 +0100

Dear all,

We would like to share and discuss with you a mechanism we called 
"Initial Spreading" (IS).

The idea consists in the combination of high IW (e.g. IW=10), jointly 
with a spacing of those segments over, at most, the first RTT of the 
connection. After the sending of the IW, we switch back to the 
scheduling of the TCP algorithms...

Our motivation lays in the fact that raising IW, as largely discussed 
previously, is good, unless the network is congested.

In that case, IS prevents the large initial burst to occur, and to this 
respect is not too aggressive for the network, but still avoids the 
drawbacks of solutions such as Pacing.

We have shown we can achieve a sounding compromise to the enhancement of 
the TCP connection startup, in various environments : LAN, wireless and 
LFN networks (including satellite access which was our initial target).

We recently presented this work to the LCN'13 conference in Sydney, 
supported by extensive NS2 simulations.
(R. Sallantin, C. Baudoin, E. Chaput, E. Dubois, F. Arnal, and A. 
Beylot, "Initial spreading: a fast start-up tcp mechanism," proceedings 
of LCN, October 23, 2013.)

The paper hasn't been published yet on IEEEXplore but should be 
available soon. A draft version of this work  is available  here :

http://www.irit.fr/publis/IRT/InitialSpreading.pdf

Finally, we have implemented this scheme in the Linux-kernel. 
Preliminary results validate the proposed scheme and our simulation 
experiments. We will open the sources and provide related packages by 
the end of January.

We are also working on the optimization of the interval between 
successive segments during the first RTT, taking into account impact of 
bursts and implementation constraints.

We would be more than happy to receive at this stage your feedback.

Renaud Sallantin
Thales Alenia Space/CNES/TeSA PhD