Quality trend measurement of long-distance VoIP communication via estimated mean opinion score

The use of Voice over IP (VoIP) applications such as Skype has revolutionised communication, shifting from Plain Old Telephone Service (POTS) transmission of analog voice signals to that of of digitised voice, video and data packets over a single shared transmission channel. However, latency and jitter remain a serious problem for VoIP and other real-time protocols in intercontinental applications. Their impact on VoIP traffic can be estimated by the ITU-T Mean Opinion Score (MOS) estimators. Our research tracks the estimated MOS across a large number of long-distance paths between different endpoint pairs as part of an ongoing longitudinal study, which times packet transmission and arrival in a global network of computers exchanging synthetic VoIP-like traffic. This paper discusses the design of the MOS estimation, the large open access data set it creates, and presents results from the first three years of operation.