User-Level Quality Assessment of a Delay-Aware Packet Dropping Scheme for VoIP

Abstract

To deal with congestion control in internet protocol (IP) networks, different active queue management schemes have been successfully proposed. However, many of these schemes do not take into consideration the particular Voice over Internet Protocol (VoIP) requirements, thereby potentially penalizing this traffic. In this paper, we propose and evaluate a dropping packet selection algorithm for queue management schemes. This algorithm, called Drop-SwD, protects VoIP traffic without affecting other User Datagram Protocol (UDP) and Transmission Control Protocol (TCP) traffic. Additionally, to preserve the quality of the VoIP service, the proposed algorithm selects the lowest quality packets (with less impact on the subjective quality) to be dropped.

The application of the algorithm in different active queue management schemes is evaluated using objective and subjective quality metrics and intelligibility metrics as well. As a result, we show that Drop-SwD improves the final quality of the voice packets’ flow, without degrading the performance of other traffic class, with respect to the packet dropping schemes of reference.