JBotSim is a multipurpose dynamic network simulator that allows to quickly prototype a distributed algorithm and test its behavior on a set of static or mobile nodes. If mobile, the nodes can be controlled by the mouse or by program.
The NEtwork Visualisation Environment is a framework for 3D-visualisation of and interaction with networks, especially communication networks as the internet in both real time and as a simulation tool. Based on JMX/Java3D.