Subject: Re: [manet] Mathematical analysis of TCP over mobile IP networks?

From: Liangping Ma <[email-masked]>
Date: Wed, 23 Oct 2002 09:48:21 -0400 (EDT)

Hi, Pete,

    I think you referred to the paper "Modeling TCP throughput: a simple
model and its empirical validation" by J. Padhye, V. Firoiu, D. Towsley
and J. Kurose in ACM SIGCOMM'98. This paper is easy to be found on the
web.

    In fact, I am looking for something a little bit different from this
paper if it exists at all. In the paper above, the analysis is for wired
networks, where packet loss is due to network congestion. But in the
_mobile_ IP networks, there is one hop of wireless link in a TCP
conneciton. The packet loss is affected also by the signal-to-noise ratio
and other factors in the wireless environment. I think these factors
should be incorporated to the so called TCP formula.

Sincerely yours,
Liangping Ma

On Wed, 23 Oct 2002, Pete Sholander wrote:

> Look at SIGCOMM '98.  There was a oft-cited paper on a mathematical
> analysis of TCP throughput versus RTT and packet-loss rate.  (I can't
> recall the author's name.) You could then do a lit-search to see who
> subsequently referenced that work.
>
> >>> Liangping Ma <[email-masked]> 10/22/02 06:51PM >>>
> Hello,
>
>    Does anyone know if there is already any work on mathematical
> analysis of TCP over mobile IP networks? As far as I know, there
> are some simulation-based studies about TCP over mobile IP networks.
> But I am looking for deterministic/stochastic modeling of TCP in
> mobile IP networks, which have one hop of wireless link as compared
> to the conventional IP networks.
>
>    Thanks!
>
> Liangping Ma
>
> -----------------------
>
> ECE Dept.
> University of Delaware
> Newark, Delaware, 19716
>
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From: Liangping Ma <[email-masked]>
Date: Wed, 23 Oct 2002 09:48:21 -0400 (EDT)

Hi, Pete,

Sincerely yours,
Liangping Ma

---

From: Saad Biaz <[email-masked]>
Date: Wed, 23 Oct 2002 09:09:08 -0500 (CDT)

> should be incorporated to the so called TCP formula.

Padhye et al. make only one assumption regarding the losses: losses are
independent from round to round. I bet that transmission losses on the
wireless hop are independent from round to round. This assumption is more
valid with wireless losses that with congestion losses.

Check Padhye's model with a wireless hop to see whether the model is that
"bad" before rejecting it.

Just an advice.

Saad.
----------------------------------------------------------------------
Saad Biaz, Ph.D., Assistant Prof.     Voice: (334) 844 6307
114 Dunstan Hall Auburn University    Fax  : (334) 844 6329
Auburn, AL 36849-5347, USA            http://www.eng.auburn.edu/~sbiaz
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From: Saad Biaz <[email-masked]>
Date: Wed, 23 Oct 2002 09:09:08 -0500 (CDT)

Just an advice.

Saad.

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From: "Prof.Anurag Kumar" <[email-masked]>
Date: Thu, 24 Oct 2002 11:17:01 +0530 (IST)

Please look at the following two papers on my site

      http://ece.iisc.ernet.in/~anurag/

* Anurag Kumar and Jack Holtzman, ``Performance Analysis of Versions of 
TCP in a Local Network with a Mobile Radio Link, '' Sadhana: Indian 
Academy of Sciences Proceedings in Engg. Sciences, February 1998.

* Anurag Kumar, ``Comparative Performance Analysis of Versions of TCP in a 
Local Network with a Lossy Link, '' IEEE/ACM Transactions on Networking, 
August 1998. 

	There are many other papers; e.g., do a search for
Chockalingam, Zorzi, Rao.

best
Anurag 

-- 
_______________________________________________________________________________
Anurag Kumar				     |e-mail: [email-masked]
Professor             			     |Phone: (+91)-80-360 0855 or
and Associate Chairman 			     |       (+91)-80-394 2387
Dept. of Electrical Communication Engg. (ECE)|Fax:   (+91)-80-360 0991 or
Indian Institute of Science (IISc)           |       (+91)-80-360 0683
Bangalore, 560 012, INDIA                    |http://ece.iisc.ernet.in/~anurag
-------------------------------------------------------------------------------

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From: "Prof.Anurag Kumar" <[email-masked]>
Date: Thu, 24 Oct 2002 11:17:01 +0530 (IST)

best
Anurag

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From: "Philippe Jacquet" <[email-masked]>
Date: Fri, 25 Oct 2002 14:09:52 +0200

I think most simple mathematical results on TCP are under the assumption of
an independent packet loss rate, therefore very close to the cases you are
looking for. In this case the window size evolution is a "simple" Markov
process, for which one derives stationary results about the window size
distribution and packet
retransmission numbers, throughput, etc. There is a nice paper of Savari and
Telatar: "the behavior of stochastic processes arising in window protocols"
(ISIT 99).

The cases with a single TCP with buffer congestion and cross interference
with other UDP traffic are more intricate even restricted on wired networks,
a paper of Baccelli and Hong:  "TCP is max-plus linear" (SIGCOM2000). In
particular there are some chaotic effects that make the TCP process very
sensitive to small variations in the initial conditions.

The case where several TCP connections share the same links became recently
an hot issue because of long term dependencies in internet traffic. One
funny outcome is that asymptotically each TCP connection behaves as if it
was experiencing an independent packet loss rate, exactly like the wireless
links case (although the analysis is carried in a wired network and loss
ocur locally in router buffer). You can take a look at our paper:

http://www.inria.fr/rrrt/rr-4478.html

Philippe

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From: "Philippe Jacquet" <[email-masked]>
Date: Fri, 25 Oct 2002 14:09:52 +0200

Philippe