A simulation method and system partitions network traffic into background traffic and explicit traffic, wherein explicit traffic is processed in detail, and background traffic is processed at a more abstract level. The packets of explicit traffic are modeled in complete detail, so that precise timing and behavior characteristics can be determined, whereas large volumes of traffic are modeled more abstractly as background flows, and only certain aspects, such as routing through the network, are simulated. Tracer packets are used to model the background traffic and carry a number of characteristics of interest for generating simulation results. In this manner, the effect of the background traffic on the explicit traffic can be modeled at each network element. The abstract processing of background traffic is facilitated by techniques that include multi-variate table look-up, neural networks, and the like.