Objective and Perceptual Impact of TCP Dropping Policies on VoIP Flows

Erika Alvarez-Flores, Juan Ramos-Munoz, Jose Lopez-Vega, Juan Lopez-Soler
The integration of voice and data has allowed the development of new services and applications on the network. Despite of the growth of voice over IP applications, main active queue management (AQM) algorithms primarily focus on TCP traffic. An AQM scheme implicitly adopts a policy for selecting the packet to be marked or dropped. However, the traditional packet selection policies do not take into account the effect on the Quality of Service for different traffic types. In this case, is not
more » ... ys satisfied the quality of service of applications such as Voice over IP (VoIP), which require limited packet delay and loss rate. In this work we study the effect of TCP dropping policy over VoIP for scenarios with mixed traffic conditions. We evaluate their objective and perceptual impact on VoIP flows. As main result, we show that the adoption of one of the proposed AQM dropping procedures improves the user's perceptual score for VoIP, with no penalty on the TCP throughput and loss rate.