Simulation has always been a valuable tool for experimentation and validation of models, architectures and mechanisms in the field of networking. In the case of the DiffServ framework, simulation is even more valuable, due to the fact that an analytical approach of mechanisms and services is infeasible because of the aggregation and multiplexing of flows. In this work, we have extended the functionality of a widely used simulation environment towards the direction of realistic traffic generation and a series of mechanisms defined by the DiffServ architecture. The modules created are being presented and a case study of a simulation scenario that exploits the functionality provided by them is described.