Recent advances in computer and communication technologies have made possible the interconnection of large number of real-time simulators via local area networks. One of the most popular network access protocols is Ethernet. In this paper we discuss some of the limitations of the Ethernet protocol when it is used to interconnect real-time simulation devices. We also introduce two modifications of Ethernet called Ethernet-1 and Ethernet-2 that remedy some of the shortcomings of the Ethernet protocol. It is worth noting that Ethernet-1 and Ethernet-2 are implementable in hardware.