[ns] How to deliberately delay the data transmission using cbrgen.tcl

[Bringo Shawn]

Hi there,
cbrgen.tcl sets the start time of data transmission between nodes randomly. I 
want to give the nodes some amount of time as warm-up period before starting 
the data transmission. And my question is how can I do this using cbrgen.tcl?

Here is my approach: I have found 'proc create-cbr-connection' procedure in 
cbrgen.tcl;

proc create-cbr-connection { src dst } {
    global rng cbr_cnt opt

    set stime [$rng uniform 0.0 180.0]
...
...
    puts "\$ns_ at $stime \"\$cbr_($cbr_cnt) start\""
...

If I change the set stime [$rng uniform 0.0 180.0] to set stime [$rng uniform 
30.0 180.0]
in case I want the warm-up period to be 30.0 seconds, can I achieve what I want 
? 

Thanks