Loss Monitor
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This document describes using the ns-2 network simulator to model and simulate network traffic over time. It defines 5 nodes connected in a network topology. It creates 3 agent/lossmonitor objects to collect packet loss statistics from 3 separate traffic flows: one from node 0 to the sink at 100kbps, one from node 1 to the sink at 200kbps, and one from node 2 to the sink at 300kbps. The simulation runs these 3 exponential traffic flows for 5 seconds, records throughput measurements every 0.5 seconds, and graphs the results.
![set n0 [$ns node]
set n1 [$ns node]
set n2 [$ns node]
set n3 [$ns node]
set n4 [$ns node]
$ns duplex-link $n0 $n3 1Mb 100ms DropTail
$ns duplex-link $n1 $n3 1Mb 100ms DropTail
$ns duplex-link $n2 $n3 1Mb 100ms DropTail
$ns duplex-link $n3 $n4 1Mb 100ms DropTail](https://image.slidesharecdn.com/lossmonitor-100726165317-phpapp02/85/Loss-Monitor-6-320.jpg)
![proc attach-expoo-traffic { node sink size burst idle rate } {
set ns [Simulator instance]
set source [new Agent/UDP]
$ns attach-agent $node $source
set traffic [new Application/Traffic/Exponential]
$traffic set packet-size $size
$traffic set burst-time $burst
$traffic set idle-time $idle
$traffic set rate $rate
$traffic attach-agent $source
$ns connect $source $sink
return $traffic
}](https://image.slidesharecdn.com/lossmonitor-100726165317-phpapp02/85/Loss-Monitor-7-320.jpg)
![set sink0 [new Agent/LossMonitor]
set sink1 [new Agent/LossMonitor]
set sink2 [new Agent/LossMonitor]
$ns attach-agent $n4 $sink0
$ns attach-agent $n4 $sink1
$ns attach-agent $n4 $sink2
set source0 [attach-expoo-traffic $n0 $sink0 200 2s 1s 100k]
set source1 [attach-expoo-traffic $n1 $sink1 200 2s 1s 200k]
set source2 [attach-expoo-traffic $n2 $sink2 200 2s 1s 300k]](https://image.slidesharecdn.com/lossmonitor-100726165317-phpapp02/85/Loss-Monitor-8-320.jpg)
![set f0 [open out0.tr w]
set f1 [open out1.tr w]
set f2 [open out2.tr w]
proc finish {} {
global f0 f1 f2
close $f0
close $f1
close $f2
exec xgraph out0.tr out1.tr out2.tr -geometry 800x400 &
exit 0
}](https://image.slidesharecdn.com/lossmonitor-100726165317-phpapp02/85/Loss-Monitor-9-320.jpg)
![proc record {} {
global sink0 sink1 sink2 f0 f1 f2
set ns [Simulator instance]
set time 0.5
set bw0 [$sink0 set bytes_]; set bw1 [$sink1 set bytes_]; set bw2 [$sink2 set bytes_];
set now [$ns now]
puts $f0 "$now [expr $bw0/$time*8/1000000]"
puts $f1 "$now [expr $bw1/$time*8/1000000]"
puts $f2 "$now [expr $bw2/$time*8/1000000]"
$sink0 set bytes_ 0; $sink1 set bytes_ 0; $sink2 set bytes_ 0;
$ns at [expr $now+$time] "record"
}](https://image.slidesharecdn.com/lossmonitor-100726165317-phpapp02/85/Loss-Monitor-10-320.jpg)
Loss Monitor
- 1. Jean Fellipe de Almeida Pimentel Túlio César Faria Pinto
- 3. Usado para monitorar números de pacotes transferidos, bem como pacotes perdidos. Pode ser usado com uma função chamada a cada X segundos e assim obter o throughput.
- 4. A classe Agent tem os seguintes atributos: addr_ Endereço de origem dst_ Endereço de destino size_ Tamanho do pacote em bytes type_ Tipo do pacote fid_ Identificador de fluxo prio_ Prioridade flags_ Flags defttl_ TTL padrão
- 5. A classe LossMonitor herda as funcionalidades de Agent Seus próprios atributos são: nlost_ Número de pacotes perdidos npkts_ Número de pacotes recebidos bytes_ Número de bytes recebidos lastPktTime_ Hora do último pacote recebido expected_ Número de sequência esperado para o próximo pacote
- 6. set n0 [$ns node] set n1 [$ns node] set n2 [$ns node] set n3 [$ns node] set n4 [$ns node] $ns duplex-link $n0 $n3 1Mb 100ms DropTail $ns duplex-link $n1 $n3 1Mb 100ms DropTail $ns duplex-link $n2 $n3 1Mb 100ms DropTail $ns duplex-link $n3 $n4 1Mb 100ms DropTail
- 7. proc attach-expoo-traffic { node sink size burst idle rate } { set ns [Simulator instance] set source [new Agent/UDP] $ns attach-agent $node $source set traffic [new Application/Traffic/Exponential] $traffic set packet-size $size $traffic set burst-time $burst $traffic set idle-time $idle $traffic set rate $rate $traffic attach-agent $source $ns connect $source $sink return $traffic }
- 8. set sink0 [new Agent/LossMonitor] set sink1 [new Agent/LossMonitor] set sink2 [new Agent/LossMonitor] $ns attach-agent $n4 $sink0 $ns attach-agent $n4 $sink1 $ns attach-agent $n4 $sink2 set source0 [attach-expoo-traffic $n0 $sink0 200 2s 1s 100k] set source1 [attach-expoo-traffic $n1 $sink1 200 2s 1s 200k] set source2 [attach-expoo-traffic $n2 $sink2 200 2s 1s 300k]
- 9. set f0 [open out0.tr w] set f1 [open out1.tr w] set f2 [open out2.tr w] proc finish {} { global f0 f1 f2 close $f0 close $f1 close $f2 exec xgraph out0.tr out1.tr out2.tr -geometry 800x400 & exit 0 }
- 10. proc record {} { global sink0 sink1 sink2 f0 f1 f2 set ns [Simulator instance] set time 0.5 set bw0 [$sink0 set bytes_]; set bw1 [$sink1 set bytes_]; set bw2 [$sink2 set bytes_]; set now [$ns now] puts $f0 "$now [expr $bw0/$time*8/1000000]" puts $f1 "$now [expr $bw1/$time*8/1000000]" puts $f2 "$now [expr $bw2/$time*8/1000000]" $sink0 set bytes_ 0; $sink1 set bytes_ 0; $sink2 set bytes_ 0; $ns at [expr $now+$time] "record" }
- 11. $ns at 0.0 "record" $ns at 1.0 "$source0 start” $ns at 1.0 "$source1 start" $ns at 1.0 "$source2 start" $ns at 5.0 "$source0 stop" $ns at 5.0 "$source1 stop" $ns at 5.0 "$source2 stop" $ns at 6.0 "finish" $ns run
- 13. Bibliografia: LossMonitor Class Reference http://www.auto-nomos.de/ns2doku/class_loss_monitor.html NS Manual www.isi.edu/nsnam/ns/doc/ns_doc.pdf Network Simulator – Visão Geral da Ferramenta de Simulação de Redes http://www.cis.udel.edu/~portnoi/articles/networksimulator-sepa.pdf