Simulators are all the rage these days. There are flight simulators; air traffic control simulators, driving simulators, city simulators and we even have network simulators.
Although the first items I mentioned
Network simulators allow the network architect or designer to create a working model of the planned network, or network upgrade. The designer can then simulate the planned network using software packages much like a flight simulator models an aircraft in flight. What if scenarios can be conducted and measurements of network traffic patterns can be performed.
Simulators are not new. Design tools such as NetFormx and NetSuite and Visio have been around for some time now. In the past, designers planned networks using these kinds of static network design tools. Visio turned out to be one of the better tools and continues to enjoy an active following. However, some of the other design tools seem to have fallen by the wayside. Their expense, difficulty and overall complexity have caused them to all but disappear.
Recently a newer crop of network simulators has appeared such as Analytical Engines' NetRule 3.1. According to Analytical Engines, NetRule is capable of modeling routing patterns and calculating round-trip delays. In these days of multimedia over networks, such information can be invaluable. NetRule is more compact than some of its predecessors and competitors. The company claims it has a small enough footprint to be run on a laptop, uses a browser-like user interface and is written in Java, so it can runs on virtually any Operating System. That is a far cry from some of the more cumbersome, less flexible network simulators of the past.
Another popular network simulator is IT DecisionGuru by OpNet Technologies. This simulator has the ability to predict the performance of networks and networkeOpnet Technologies d applications. It can also diagnose network problems, and perform failure studies