A Simulation Study of Relationships between Delay Jitter and Properties of a Switching Network

Delay jitter is one of the most important Quality-ofService (QoS) parameters in the transmission of real-time multimedia traffic over networks. While delay jitter has been extensively studied in relation to various scheduling and routing algorithms, it has rarely been studied in relation to the properties of the network topology and the internal architecture of switching elements. The relationships between delay jitter and various attributes of the network are important in best-effort networks such as the Internet as well as in networks that allow negotiation of QoS parameters, such as in ATM networks. In this paper, we present a brief simulation study of this relationship, focusing on the number of stages, the size of the switching elements and the buffering strategies within the switching elements. Our results on the number of stages and the size of switching elements are relevant to switch-based multistage networks such as in ATM networks and many networked multimedia systems. Our results on buffering strategies are relevant to all networks that use switches or routers with output queuing, such as ATM networks and the Internet. Our results show that the number of stages or the number of hops has the dominant impact on the delay jitter in a multimedia stream, as compared to other aspects of the network such as the buffering strategy within the switching elements.