Alvaro Saurin — Congestion Control for Video-conferencing Applications

Congratulations to Alvaro Saurin, who has completed his MSc thesis on Congestion Control for Video-conferencing Applications, looking into how well TCP-Friendly Rate Control (TFRC) works on real-world networks.

The abstract reads:

In the Internet, transmission systems must deal with congestion in order to keep the stability of the network. However, the model used for congestion control determines some important properties of the traffic. The most important algorithm currently used, found in the TCP protocol, has characteristics that make it unsuitable for videoconferencing systems.

The aim of this dissertation is to provide an insight into the field of congestion control for such systems. In particular, this work examines one of the most promising alternatives available, TCP-Friendly Rate Control (TFRC), to answer the question “is TFRC suitable for interactive videoconferencing applications?”

This dissertation presents the results obtained with TFRC, focusing on some practical aspects and providing recommendations for the implementation of such a rate-based congestion control system. This work examines the scenarios where TFRC is an adequate solution, exposing the behavior that can be expected and suggesting future improvements.

The thesis also presents the experiences of integrating TFRC in the UltraGrid videoconferencing application. It shows the difficulties found, demonstrating that this integration requires an significant amount of support from the application, and questioning the suit- ability of TFRC in some situations.

This works was completed as part of the NSF-funded UltraGrid project.