[UCI-Calit2] Upcoming Event: Avoiding Oscillations Due to Intelligent Route Control Systems

Anna Lynn Spitzer aspitzer at rgs.uci.edu
Mon May 15 13:50:38 PDT 2006


Title:		Avoiding Oscillations due to Intelligent Route Control
Systems


Speaker:	Constantine Dovrolis, assistant professor, College of
Computing, Georgia Institute of Technology


Time:		Refreshments, 1:45 p.m.; lecture, 2-3 p.m.


Date:		Thursday, May 18, 2006


Location:	Calit2 Building, Room 3008


Abstract:	Intelligent Route Control (IRC) systems are increasingly
deployed in multihomed networks. IRC systems aim to optimize the cost
and performance of outgoing traffic, based on measurement-driven dynamic
path-switching techniques. In this paper, we first show that IRC systems
can introduce sustained traffic oscillations, causing significant
performance degradation instead of improvement. This happens, first,
when IRC systems do not take into account the self-load effect, i.e.,
when they ignore that the performance of a path can change after
additional traffic is switched to that path. Second, oscillations can
take place when different IRC systems get synchronized due to
significant overlap of their measurement time windows. We then propose
measurement methodologies and path-switching algorithms that can
effectively deal with the previous two issues. The proposed IRC
techniques use available bandwidth estimation to avoid the self-load
effect, and they introduce a random component in the path-switching
decision or time scale. We evaluate the proposed techniques under
diverse traffic conditions. When the background traffic is stationary,
IRC systems should switch paths conservatively, only upon major traffic
fluctuations. With non-stationary background traffic and congestion
periods that last for a time scale Tw, IRC systems improve performance
only if they can detect congestion and switch paths much faster than Tw;
otherwise, they cause oscillations and hurt performance.

We also show that the gradual deployment of randomized IRC systems, in
the presence of traffic from deterministic IRC systems, can play a
stabilizing role and benefits early adopters.


Bio:		Constantine Dovrolis is an assistant professor at the
College of Computing of the Georgia Institute of Technology. He received
the computer engineering degree from the Technical University of Crete
(Greece) in 1995, the master's degree from the University of Rochester
in 1996, and the doctorate degree from the University of
Wisconsin-Madison in 2000. His research interests include methodologies
and applications of network measurements, bandwidth estimation
algorithms and tools, overlay networks, service differentiation and
network problem diagnosis. He received the NSF CAREER award in 2004.


Additional Info:	Faculty Host: Athena Markopoulou,
athina at uci.edu.

	


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