Modeling of Packet Loss and Delay and Their Effect on Real-Time

Abstract

Internet packet loss and delay exhibits temporal dependency. If packet n is lost, packet n + 1 is also likely to be lost. It leads to bursty network losses and late losses in real-time multimedia services such as Voice over IP (VoIP). This may degrade perceptual quality and the effectiveness of Forward Error Correction (FEC). To characterize this burstiness, we first discuss the modeling of packet loss and delay. We propose the joint use of the extended Gilbert model and the inter-loss distance (ILD) metric to characterize temporal loss dependency. For delay, we introduce a metric called the conditional cumulative distribution function. We have applied these models to some Internet packet traces to validate the necessity and effectiveness of these models. We then evaluate the effect of these dependencies on VoIP by investigating the final loss pattern (FLP) after applying playout delay adjustment and FEC. Our results through a set of simulations confirmed that the FLP is still bursty.