How to Count Packets Actively in Ns2

You can do it by modifying the .cc and .h files of the queue implementation which can be found  at

ns-allinone-x.xx\ns-x.xx\queue.

You need to add some private variables and functions to read and write those variable  in the class structure.

You should  update the value on each en-queue operation.

Instead of using IP address as index, you may use node ID.