Network simulation is an integral part of Simics. Simics is used in the real world to simulate very large networks of systems, scaling up to several thousand-target processors spread across dozens or even hundreds of networked boards. This paper discusses how networks are used in Simics target systems in many different ways. The simplest case is a single computer board that is connected to the outside world via an Ethernet link. There are target systems that just combine a few separate computers over Ethernet to model a small office network.