AnyLogic - AnyLogic has changed simulation modeling and expanded its application into complex business environments. The unmatched flexibility of multimethod modeling allows users to capture the complexity of virtually any system, at any level of detail.
GNS3 - GNS3 is a graphical network simulator that allows simulation of complex networks.
ns-3 - a discrete-event network simulator for internet systems
NetSim - NetSim software was created to simulate various Cisco systems. Cisco software is known around the world as being one of the best network, routing and switch systems for businesses and private use. Read more about NetSim.
SIMUL8 - Simulation is an effective system that permits you to make striking, certain choices since it gives you the confirmation to make certain you are settling on the right decision.
Free SNMP Agent Simulator - Verax Systems provides applications covering the entire IT & Telco service lifecycle from definition through provisioning and monitoring up to billing.