In this paper we present a methodology for the evaluation of networked systems communicating using WLAN technology. We show a case study of goal-oriented cooperating robots, for which our approach is particularly useful. Developing robots is expensive; hence emulation can be employed in the first part of the development cycle to study robot software implementations in realistic conditions at a reduced cost. Our methodology is based on the emulation of both the robots and the WLAN communication technology. The robots we consider cooperate in order to efficiently reach a destination while avoiding collisions with obstacles and other robots. The WLAN communication emulation engine QOMET is deployed in the emulated robots to recreate network conditions similar to those occurring in a real WLAN environment. The experiments are run on a large-scale network experiment environment, StarBED, using the support software RUNE. Currently, over one hundred emulated robots can be run simultaneously ...