Catherine Boutremans

Learn More
Consider a network with an arbitrary topology and arbitrary communication delays, in which congestion control is based on additive–increase and multiplicative– decrease. We show that the source rates tend to be distributed in order to maximize an objective function called F h A (“F h A fairness”). We derive this result under the assumption of rate(More)
We develop a joint playout buffer and Forward Error Correction (FEC) adjustment scheme for Internet Telephony, which incorporates the impact of end-to-end delay on the perceived audio quality. We show that it provides better quality than the adjustment schemes for playout buffer and FEC that were previously published. This is important because of a(More)
In this work, we address the question of how to enable a system to operate despite the presence of misbehavior. Specifically, in a mobile ad-hoc network, how can we keep the network functional for normal nodes when other nodes do not route and forward correctly? Node misbehavior due to selfish or malicious reasons or faulty nodes can significantly degrade(More)
We use active and passive traffic measurements to identify the issues involved in the deployment of a voice service over a tier-1 IP backbone network. Our findings indicate that no specific handling of voice packets (i.e. QoS differentiation) is needed in the current backbone but new protocols and mechanisms need to be introduced to provide a better(More)
Forward Error Correction copes with packet losses, but at the expense of an increase of the end-to-end delay. By failing to take this into account, existing error control schemes for audio often lead to endto-end delays larger than 150 ms, which has an impact on the perceived audio quality. In this paper, we develop an adaptive error control scheme for(More)
Current TCP-friendly congestion control mechanisms adjust the packet rate in order to adapt to network conditions and obtain a throughput not exceeding that of a TCP connection operating under the same conditions. In an environment where the bottleneck resource is packet processing, this is the correct behavior. However, if the bottleneck resource is(More)
Current TCP-friendly congestion control mechanisms such as those used in TFRC adjust the packet rate in order to adapt to network conditions and obtain a throughput not exceeding that of a TCP connection operating under the same conditions. In an environment where the bottleneck resource is packet processing, this is the correct behavior. However, if the(More)
We study the fairness of TCP Vegas. The latter is an alternative to the commonly used TCP Reno, and uses measures of the round trip time as feedback on congestion. We consider two cases that depend on the value of the two parameters and controlling the window sizes' update. Our main conclusion is that TCP Vegas is unfair in several points. First, when = ,(More)
In this work, we address the transport of high quality voice over the Internet with a particular concern for delays. Transport of interactive audio over IP networks often suffers from packet loss and variations in the network delay (jitter). Forward Error Correction (FEC) mitigates the impact of packet loss at the expense of an increase of the end-to-end(More)