[ns] LossMonitor in multicast

[mike lui <jhc8459@yahoo.com>]

Hi Ns users

I'm trying to collect statistic such as throughput,
packet loss rate on each receiver side in mftp. I have
tried Agent/LossMonitor but it doesn't collect any
parameters. Here is my Tcl code snippet.

proc record { } {
   global srvNode sink n thru loss_rate
   set ns [Simulator instance] 
   set time 0.5           
   for {set i 0} {$i <$srvNode} {incr i} {
        set  recv_pkt($i) [$sink($i) set npkts_]
        set  lost_pkt($i) [$sink($i) set nlost_]
        set  recv_byt($i) [$sink($i) set bytes_]
       puts stdout "node($i) $bw($i) $recv_pkt($i)
$lost_pkt($i)"
   }
  set now [$ns now] ; #get the current time
   #calculate thrughput 
for {set i 0} {$i <$srvNode} {incr i} {
  puts $thru($i) "$now [expr
$recv_byt($i)/$time*8/1000000]"
  }
   #reset the bytes_ values on the traffic sinks
    for {set i 0} {$i <$srvNode} {incr i} {
         $sink($i) set bytes_ 0
         $sink($i) set nlost_ 0
        }
   #reschedule the procedure
    $ns at [expr $now+$time] "record"
}

One discrepancy from tutorial is that I didn't include
$ns connect $source $sink
because it's multicasting. On simualtion, nam shows 
traffic is flowing well but any reason I couldn't
collect traffics. Any help will be appreciated.. 

mike lui


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