ATM switching fabrics are good candidates to implement high performance parallel event builders for the future data acquisition systems of the LHC experiments. We are studying their feasibility through simulations and implementation of event builder demonstrators. The impact of the event builder characteristic traffic pattern on the switch has been studied and methods to avoid congestion in the switch have been proposed. Event building algorithms and data acquisition protocols have been developed. Measurements made with a demonstrator and comparisons with simulation studies are presented. The scalability of the measurements is discussed.