[Iccrg] suggestions on fairness metrics to the TCP evaluation suite round-table

[Sándor Molnár]

Hi All,

We have recently completed a project on the fairness analysis of high
speed transport protocols. One of our result is that we suggest a new
performance metric (saturation time) that can be important from the
dynamical aspects of interacting protocols. We have found that the
short-term dynamics could have significant impacts on long-term
fairness. We hope it is relevant to the topic of TCP evaluation suite
round-table, especially to convergence time. Our results can be found in
our downloadable technical report, see below.

The website of our project:
http://qosip.tmit.bme.hu/~sonkoly/Tcp/

The technical report can be downloaded from:
http://qosip.tmit.bme.hu/~sonkoly/Tcp/files/Technical_Report.pdf

I also included the abstract of the report.

Abstract
---------
The short-term dynamics of competing high speed TCP flows could have
surprising impacts on their long-term fairness.  As a result, this could
have a severe impact on the co-existence and, finally, the deployment
feasibility of different seemingly promising proposals for the next
generation networks. However, to our best knowledge, no root-cause
analysis of the observation is available. This is the major motivation
of our work.

The contribution of the paper is twofold. First, we present our
comprehensive performance evaluation results of both inter- and
intra-protocol fairness behavior of different TCP versions to get an
overall view of these protocols. The analysis has revealed not only the
equilibrium behavior but also the transient characteristics with the
dynamic behavior. Second, we have performed a root-cause analysis to get
a deeper understanding in the case of some of the promising TCP
versions. This study not only fills the "black holes", the questions
which remained unanswered in some cases but rather goes deeper and
investigates questions which have never been asked yet. The analysis
spans multiple dimensions: flow-level, packet-level, queueing and
spectral analysis. Three loss-based (HighSpeed TCP, Scalable TCP and BIC
TCP) approaches and the delay-based FAST are investigated in details
with both dumb-bell and parking-lot topologies.

Regards,
Sandor