Don Towsley , University of Massachusetts, Amherst

Location :

LIP6 
104, avenue du President Kennedy
Salle 549
75016, Paris 

RER: Ligne C, station "Avenue du President Kennedy - Maison de Radio-France"
Métro : Ligne 6, station "Passy" 

Abstract :

The distribution of network flow sizes is an important yet difficult metric to estimate in a 
network. It is important because it characterizes traffic compositions and is a crucial component of 
anomaly detection methods. It is difficult to estimate because of its high memory and 
computational requirements.  In this talk we report on two different methods for estimating the flow 
size distribution.  The first part of the talk focuses on flow size estimation based on packet sampling 
(e.g., NetFlow). Our discussion of this method emphasizes the use of Fisher Information as the 
metric for evaluating the benefits of different types of information on flow size distribution estimation. 
For example, when we restrict ourselves to TCP flows, the Fisher Information tells us that simply 
counting the number of packets per flow does not produce an accurate estimate of the size 
distribution of such flows (contrary to earlier reported results), whereas the inclusion of 
information such as sequence numbers makes the estimation problem tractable.

In the second half of the talk, we focus on flow size estimation based on an on-line data 
streaming approach. Our discussion of this approach focuses on the use of probabilistic 
counting and counter folding, both of which allow for a substantial reduction, over previous 
algorithms, in the amount of processing and the amount of memory needed to obtain accurate 
estimates of the flow size distribution.

This work was performed jointly with Bruno Ribeiro and Tao Ye.

Biography
Don Towsley is a Professor at the University of Massachusetts in the Department of Computer 
Science.  His research interests include networks and performance evaluation.  He currently serves 
as Editor-in-Chief of IEEE/ACM Transactions on Networking, and on the editorial boards of Journal 
of the ACM and IEEE Journal on Selected Areas in Communications.  He was Program Co-chair of 
the joint ACM SIGMETRICS and PERFORMANCE '92 conference and the 
Performance 2002 conference.

Towsley has received the 2007 IEEE Koji Kobayashi Award, the 2007 ACM SIGMETRICS 
Achievement Award,the 2008 ACM SIGCOMM Lifetime Achievement Award, a 2008 SIGCOMM 
Test-of-Time Paper Award, the 1998 IEEE Communications Society William Bennett Best 
Paper Award, and numerous conference/workshop best paper awards. Last, he has been elected 
Fellow of both the ACM and IEEE. 

Host :

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