25.1.1.1 Example

 # Usage: ns rng-test.tcl [replication number]

 if {$argc > 1} {
    puts "Usage: ns rng-test.tcl \[replication number\]"
    exit
 }
 set run 1
 if {$argc == 1} {
    set run [lindex $argv 0]
 }
 if {$run < 1} {
    set run 1
 }

 # seed the default RNG
 global defaultRNG
 $defaultRNG seed 9999

 # create the RNGs and set them to the correct substream
 set arrivalRNG [new RNG]
 set sizeRNG [new RNG]
 for {set j 1} {$j < $run} {incr j} {
    $arrivalRNG next-substream
    $sizeRNG next-substream
 }

 # arrival_ is a exponential random variable describing the time
 # between consecutive packet arrivals
 set arrival_ [new RandomVariable/Exponential]
 $arrival_ set avg_ 5
 $arrival_ use-rng $arrivalRNG

 # size_ is a uniform random variable describing packet sizes
 set size_ [new RandomVariable/Uniform]
 $size_ set min_ 100
 $size_ set max_ 5000
 $size_ use-rng $sizeRNG

 # print the first 5 arrival times and sizes
 for {set j 0} {$j < 5} {incr j} {
    puts [format "%-8.3f  %-4d" [$arrival_ value] \
            [expr round([$size_ value])]]
 }