See tnlNetBase.h for a full description of the use of class IDs. NetClassRep is the class that handles assigning of ids. To be honest, you don't really need to worry about class IDs for your application (that is, if you are just using TNL to build a networked application). They are just a method for generating arbitrary classes at run time - this is handled transparently for you by TNL or TGE/TSE.
Torque Owner Shyam "Doggan" Guthikonda