[ns] Simple emulation script for RedHat Linux

["Jason K. Douglas" <jkdoug@psu.edu>]

I have been trying to create/modify an emulations script for ns on RedHat 
7.1.  I started with emping.tcl and modified it to connect to eth0 instead of 
fxp0.  When I run the script and ping myself a few times, the nam trace file 
contains no messages.  Am I setting something up incorrectly?  Has anyone 
successfully executed an emulation script on RedHat (or other) Linux 
recently?  I'm unfamiliar with any methods to debug the script to see if the 
messages are being dropped.

Also, where can I find documentation on BPF syntax?  The only clue I have to 
create my own filter is from the emulation sample scripts.

If you need to see the script, or anything else, please ask.  I need to get 
this realtime live network simulation running very soon...

Thanks,
Jason