Recent breakthroughs in communications technology have led to the emergence of new network protocols with unprecedented high speeds. Two such protocols are the Fiber Distributed Data Interface (FDDI) and the express Transmission Protocol (XTP). In this paper, we present the results of an ongoing performance evaluation project to study/assess the evolution of real-time training networks (e.g., SIMNET) to FDDI and XTP. Both the long-range and short-range design policies for the integration of these high speed protocols into simulation networks are considered. Gatewaying methods specially tailored for FDDI backbones connecting multiple local-area simulation networks are discussed. The implications of the results and the insight gained from our project for improving the networking of real-time simulators are discussed.