Iordanis Koutsopoulos, University of Thessaly

Location :

Thomson Paris Lab

Abstract :

In the first part of the talk, I will provide an overview of ongoing 
research activities within the Networking Group at University of Thessaly.

In the second part of the talk, I will discuss the problem of distributed 
bandwidth  sharing in peer-to-peer networks. In peer-to-peer networks, each 
peer plays the role of client and server. As server, it receives content 
requests of others and decides to what extent it will satisfy them by 
allocating upload bandwidth. As client, it sends its own requests to 
others to download content. 

We consider a star topology network with the capacity bottleneck being the 
peer access link to the backbone. Peers have different utility functions 
which are private information and capture a peer's selfishness or desire 
for content. Setting off from maximization of sum utility as the objective, we 
study bandwidth sharing between download flows of each peer and upload flows of 
others and how this can be performed in a decentralized autonomous fashion. 

We formulate and solve the problem using dual decomposition. En route to 
the solution, we devise meaningful reputation-driven protocol with the 
desirable property that only amounts of requested and granted bandwidth 
are circulated, and not reputations. 

Iordanis Koutsopoulos is Lecturer (to be promoted to Assistant Professor) at 
the Department of Computer and Communications Engineering, University of 
Thessaly, Greece. 

He obtained the Diploma in Electrical and Computer Engineering from 
the National Technical University of Athens, Athens, Greece in 1997 and the 
M.S and Ph.D degrees in Electrical and Computer Engineering from the University 
of Maryland, College Park (UMCP) in 1999 and 2002 respectively. From 1997 to 
2002 he was a Fulbright Fellow and a Research Assistant with the Institute for 
Systems Research (ISR) of UMCP. He has held internship positions with Hughes 
Network Systems, Germantown, MD, Hughes Research Laboratories LLC, Malibu, CA, 
and Aperto Networks Inc., Milpitas, CA, in 1998, 1999 and 2000 respectively. 
For the summer period of 2005 he was a visiting scholar with University of 
Washington, Seattle, WA. For the period 2005-2007 he was awarded the Marie 
Curie International Reintegration Grant (IRG). 

His research interests are in the field of networking with emphasis on wireless 
networks, cross-layer design, sensor networks, smart antennas and more 
recently on wireless network security and peer-to-peer networks.

Host :

Theodoros Salonidis