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Hi
 I am trying to measure jitter between the two node but it gives me
following error
ns: dump _o15 1: can't read "jitter": no such variable
    while executing
"set $jitter [[expr $delay+1]-$delay]"
    (procedure "dump" line 11)
    invoked from within
"dump _o15 1"

My script is

#set ns [new Simulator]
set n0 [$ns node]
set n1 [$ns node]
$ns duplex-link $n0 $n1 5Mb 2ms DropTail
## Set up BSD Tahoe TCP connection in opposite directions.
set src1 [$ns create-connection TCP $n0 TCPSink $n1 1]
set src2 [$ns create-connection TCP $n1 TCPSink $n0 2]
# Create ftp sources at the each node
set ftp1 [$src1 attach-app FTP]
set ftp2 [$src2 attach-app FTP]
# Start up the first ftp at the time 0 and
# the second ftp staggered 1 second later
#$ns at 0.0 "$ftp1 start"
$ns at 1.0 "$ftp2 start"
## Create a trace and arrange for all link
# events to be dumped to "out.tr"
#set tf [open out.tr w]
$ns trace-queue $n0 $n1 $tf
set qmon [$ns monitor-queue $n0 $n1 ""]
set integ [$qmon get-bytes-integrator]
## Dump the queueing delay on the n0->n1 link
# to stdout every second of simulation time.
#proc dump { link interval } {
	global ns integ
	#global ns temp
	$ns at [expr [$ns now] + $interval] "dump $link $interval"
	set delay [expr 8*[$integ set sum_] / [[$link link] set
bandwidth_]]
	#set $temp delay
	set $jitter [[expr $delay+1]-$delay]
puts "[$ns now] jitter=$jitter"
}
$ns at 0.0 "dump [$ns link $n0 $n1] 1"
## run the simulation for 20 simulated seconds
#$ns at 15.0 "$ns halt; exit 0"
$ns run

Would you please what is  wrong here?

Thank!

KAt