This chapter compares exponential, Pareto, Poisson, and constant bit rate (CBR) packet arrival processes. It discusses the impact of packet arrival distribution on 802.11 networks. The chapter provides the impact of traffic arrival processes and transport protocols on Wireless local area networks (WLAN). It shows that simulation models to investigate the effect of arrival processes on WLAN performance. The chapter analyzes the effect of four diverse traffic models on the performance of a typical 802.11b single-hop ad hoc network for Transmission Control Protocol and User Datagram Protocol streams. The four different traffic models, exponential, Pareto, Poisson, and CBR, are used to control the traffic loads. Of the four traffic models considered, Poisson arrivals result in the best fairness performance under all loads. From a real application point of view a question may arise about the choice of the right traffic distribution model for a particular application.