Subject: [iccrg] Initial Spreading: a proposal to safely enlarge the TCP's IW

From: renaud sallantin <[email-masked]>
Date: Sat, 21 Dec 2013 17:31:02 +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 spreading 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.

Do we have to ask for an ID first?

Renaud Sallantin
Thales Alenia Space/CNES/TeSA PhD

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From: Michael Welzl <[email-masked]>
Date: Sat, 21 Dec 2013 17:46:44 +0100

Hi,

> Do we have to ask for an ID first?

You don't "ask for an ID", you write it. However, having written an ID is not at all necessary for a discussion in a RG (neither on the list nor at a meeting), and a discussion like this one is extremely welcome here.

Cheers,
Michael