I think you want the buffer less network. In your code(TCL) you can assign delay time is zero. In ns2 architectural module you have to change the corresponding values, then builds. Configuration be proceeded.  

I think you need to go through the ns2 source code and find the queue implementation already present there. In that source file you may add your own queue implementation and make the necessary changes in the header files. Then recompile the ns2 source.

hi

If you want to implement this queue go to this link.

http://nile.wpi.edu/NS/

then to add new queue and follow the steps. It is one of the best examples