[ns] Problem with queue size

[Hassan Mansouri <hmansour@usc.edu>]

Dear ns users, Hello.

I tried to get the size of the queue in a link using the proc below
and although I could see the packets piling up and even dropping the 
output of the queue size was 0 at all time. Can you please help?
Thanks alot.

proc record {} {
        global ns n mf 
        #Set the time after which the procedure should be called again
        set time 0.002
        #Get the size of the queue of each link
        set q [$ns monitor-queue $n(1) $n(2) ""]
        set q12 [$q set size_]
        puts $q12
        #Get the current time
        set now [$ns now]
        #Write to the file
        puts $mf "$now $q12"
        #Re-schefule the procedure
        $ns at [expr $now + $time] "record"

}

Hassan.