Quality assessment of VoIP services: a proposal based on the measurement of the IP Packet Delay Variation

Generally, the voice quality of a VoIP call can be analyzed through the measurement of suitable metrics at the application layer of the International Organization for Standardization/Open Systems Interconnection (ISO/OSI) protocol stack. However, the peculiarities of such a kind of measurements make very difficult to provide to each user a value representative of the quality of each VoIP call. On the other hand, the performance of VoIP services is strongly influenced by the Internet Protocol Packet Delay Variation (IPDV) value, which is a typical metric for Quality of Service (QoS) measurements at transport layer and that can be more easily and reliably estimated than metrics at application layer. In this paper, the study of the correlation among the measured IPDV values and performance metrics, directly related to the quality perceived by the user (at application layer), in VoIP applications is proposed. It represents a first step for designing an IPDV estimator able to reliably forecast objective service degradation from the user perspective.