[Fwd: Democritos IT- seminar announcement:]

[Alvise Nobile]

Friday 17th of November 2PM
SISSA - Room A

Title: TCP Libra: Maintaining  Fairness at High Speed

Speaker:  Giovanni Pau, UCLA  / Egrid

Abstract:

The majority of Internet users rely on the Transmission Control Protocol 
(TCP) to download large data and multimedia files from remote servers 
(i.e. P2P file sharing). The current TCP new reno is aging and is 
becoming obsolete for today's high speed networks.
In particular,  TCP suffers from scalability and RTT fairness issues. 
For instance, when session round-trip-times (RTTs) radically differ, the 
share (of the bottleneck link) may be anything but fair; and when used 
in long distance high gigabit networks the link utilization is far from 
optimal.
This motivates us to explore a new TCP, TCP Libra, which guarantees fair 
sharing regardless of RTT while achieving almost 100\% efficiency in 
high-speed networks.
The key element of TCP Libra is the unique window adjustment algorithm 
that provably leads  to an RTT-independent throughput for each flow, 
thus converging to fair share. We position TCP Libra in a non-linear 
optimization framework, proving that it provides fairness (in the sense 
of max-min fairness of potential delays) among TCP flows that share the 
same bottleneck link. Equally important is friendliness of Libra towards 
legacy TCP.
TCP Libra features {\bf RTT fairness},  {\bf TCP New Reno friendliness} 
and the {\bf ability to scale} in multi-gigabit networks.
TCP Libra is has been implemented for Linux 2.6.15. An NS 2 simulation 
model is also available. Via analytic modeling, simulation, and 
measurement experiments, we show that TCP Libra achieves top efficiency 
while maintaining fairness and friendliness to TCP New Reno. A 
comparison with other TCP versions that have been reported as 
\textit{RTT-fair} in literature is also carried out.