Analytical modeling of traffic sources in a packet-switched communications network is the basis of performance analysis and network design. Along with the development of high speed networks, more types of traffic are being applied to the network, such as real time video traffic and multimedia traffic with voice, data, image and video. To support quality service for various types of traffic, it is very important to characterize the properties of the traffic through accurate modeling. For decades, traffic modeling has been an active research area.