Connecting simulated machines over a simulated Ethernet connection is done by creating an ethernet-link object that connects to the Ethernet devices in the machines. The link object can be thought of as modeling an Ethernet cable that is plugged in to the connectors on the devices.
The link object models Ethernet at the frame level, in that it performs delivery of complete frames sent from one device to any other device connected to the link, and doesn't model collisions or lower-level signaling details. This means that it can be used either to model point-to-point twisted-pair or fiber cables running at any speed, or even a 10BASE2 or 10BASE5 traditional coaxial bus, without any changes to the model. Another way of viewing ethernet-link is to see it as an Ethernet hub or switch to which can be connected two or more devices.
Traffic sent over the link can be anything, including TCP/IP or any other protocol stack that works on top of Ethernet. The link object doesn't need to be configured with any information about how it will be used.
New ethernet-link objects can be added with the new-ethernet-link command:
simics> new-ethernet-link Created ethernet-link ethlink0