It is hard to find the relation between different classes and functions!

[K Sun <ksun@essex.ac.uk>]

Hello, 
    I have read quite a little about ns programming.
However, until now, I have not known clearly what the internal 
operating meachanism of ns-2 is. 
    For example, the classifier in node can allocate different packet 
in different ports in a node. However, how does it know these ports are 
connected with the correct route by which the packet may get to its 
desirable destination? What functions connect the operation of 
classifier with the routing function. It is really difficult for me to 
find the specific relation between these operations like this. I really 
hope there are some statement about these operation mechanisms of ns-2.

    Regards,

         Sun Kai