[ns] generate on/off tcp traffic

[曲晶莹]

Hi，all
I want to generate background traffic.Does anybody know how to generate
on/off tcp traffic in NS2 ?
Any answer will be respected.
Thanks in advance.  :-) 

[ns] how to add shell script or shell command into tcl script.

[曲晶莹]

hi, all
I wonder to know how to add shell script or shell command into tcl script.
Thank you very much in advance.  :) 

jingle