On the Long-Range Dependent Behaviour of Unidirectional Packet Delay of Wireless Traffic

In contrast to aggregate inter-packet metrics that quantify the arrival processes of aggregate traffic at a single point in the network, intraflow end-to-end per-packet performance metrics assess the level of service quality experienced by certain traffic types while routed over a network path. Consequently, while the former is influenced by the superimposition of a large number of concurrent ON/OFF sources, the latter mainly depends on the specific transport mechanisms employed by individual flows in conjunction with the temporal resource contention along the end-to-end path. In this paper, we have used a ubiquitous measurement technique to assess the unidirectional end-to-end delay characteristics experienced by diverse sets of IPv6 flows routed over heterogeneous wireless network configurations. We analysed numerous traces to find that, when viewed as time series data, often exhibit long-range dependence manifested by Hurst parameter estimates greater than 0.5. Our results suggest that the end-to-end packet delay can be bursty across multiple time scales even at the microflow level, implying high performance variability during sufficiently long-lived application sessions. We anticipate that the quantification of such intraflow phenomena can enable applications to optimise and adjust their operation in the face of potential performance degradation.