'''NS2 simulator''': From the interpreted hierarchy, we can also retrieve the simulator instance by invoking instproc '''instance{}''' of class '''Simulator'''. This instproc executes the OTcl built-in command "info" with an option "instances". This execution returns all the instances of a certain class. Since there is only one Simulator instance, the statement "Simulator info instances" returns the Simulator object as required (From: T.Issariyakul, E.Hossain, ''Introduction to Network Simulator NS2'', (c) Springer Science+Business Media, LLC 2009)
