[ns] Traffic generator option ( "connection" vs "actives nodes" )

[Zakia Khalfallah]

Hi Friends,
This is the options related to a traffic generator whith which i must work in 
my project :

 ./trafgen    -n <nodes> -a <active nodes> -t <simulation time> -c <connections>

Any one has an idea about the difference between : " active nodes" and " 
connections"? 

Thank you
ZAK