sir, I am using below tcl code to generate xgraph but it give the following error:
"can't read "n0": no such variable while executing "$ns attach-agent $n0 $udp0" (procedure "attach-expoo-traffic" line 6) invoked from within "attach-expoo-traffic $n4 $Sink0 200 2s 1s 100k" invoked from within "set udp0 [attach-expoo-traffic $n4 $Sink0 200 2s 1s 100k]" (file "blue1.tcl" line 145)" ---------------------------------blue.tcl------------------------------------------------------------------- #script illustrating the BLUE algorithm #Senders are TCP-SACK senders, and receivers are TCP-SACK sinks set ns [new Simulator] # turn on ns and nam tracing $ns color 0 red #set the no of TCP flows here set f0 [open out0.tr w] set f1 [open out1.tr w] set f2 [open out2.nam w] $ns namtrace-all $f2 # create the nodes #First create TCP senders and receivers set n0 [$ns node] set n1 [$ns node] set n2 [$ns node] set n3 [$ns node] set n4 [$ns node] set n5 [$ns node] # create the links #betwwen the senders and n1, receivers and n2 $ns duplex-link $n0 $n2 10Mb 1ms DropTail $ns duplex-link $n1 $n2 10Mb 1ms DropTail #Bottle neck link between between n1 and n2 $ns simplex-link $n2 $n3 1Mbps 100ms Blue $ns simplex-link $n4 $n3 1Mbps 100ms DropTail $ns simplex-link $n5 $n3 1Mbps 100ms DropTail proc finish {} { global ns f0 f1 f2 f3 $ns flush-trace close $f0 close $f1 close $f2 exec nam out2.nam & exec xgraph out0.tr out1.tr -geometry 800x400 & exit 0 } #Configure BLUE queue parameters here set blueq [[$ns link $n2 $n3] queue] $blueq set decrement 0.00025 $blueq set increment 0.0025 $blueq set dhold-time 100ms $blueq set ihold-time 100ms #Enable ECN here $blueq set setbit true #set the queue-limit between n1 and n2 $ns queue-limit $n2 $n3 50 #set up queue monitor, sample every 0.5 seconds set qfile [open "test-blue-qsize.out" w] set qm [$ns monitor-queue $n2 $n3 $qfile 0.5] [$ns link $n2 $n3] queue-sample-timeout proc attach-expoo-traffic { node sink size burst idle rate } { set ns [Simulator instance] set udp0 [new Agent/UDP] $udp0 set fid_ 1 $udp0 set ecn_ 1 $ns attach-agent $n0 $udp0 set udp1 [new Agent/UDP] $udp1 set fid_ 2 $udp1 set ecn_ 1 $ns attach-agent $n1 $udp1 #set Sink0 [new Agent/TCPSink/Sack1/DeAck] #$Sink0 set ecn_ 1 #$ns attach-agent $n4 $Sink0 #set Sink1 [new Agent/TCPSink/Sack1/DeAck] #$Sink1 set ecn_ 1 #$ns attach-agent $n5 $Sink1 set traffic0 [new Application/Traffic/Pareto] $traffic0 set packetSize_ 1000 $traffic0 set burst_time_ 200ms $traffic0 set idle_time_ 200ms $traffic0 set shape_ 1.5 $traffic0 set rate_ 10000K $traffic0 attach-agent $udp0 set traffic1 [new Application/Traffic/Pareto] $traffic1 set packetSize_ 1000 $traffic1 set burst_time_ 200ms $traffic1 set idle_time_ 200ms $traffic1 set shape_ 1.5 $traffic1 set rate_ 10000K $traffic1 attach-agent $udp1 $ns connect $udp0 $Sink0 $ns connect $udp1 $Sink1 return $traffic0 return $traffic1 } proc record {} { global Sink0 Sink1 f0 f1 set ns [Simulator instance] set time 0.5 set bw0 [$Sink0 set bytes_] set bw1 [$Sink1 set bytes_] set now [$ns now] puts $f0 "$now [expr $bw0/$time*8/1000000]" puts $f1 "$now [expr $bw1/$time*8/1000000]" $Sink0 set bytes_ 0 $Sink1 set bytes_ 0 $ns at [expr $now+$time] "record" } set Sink0 [new Agent/LossMonitor] set Sink1 [new Agent/LossMonitor] $ns attach-agent $n4 $Sink0 $ns attach-agent $n5 $Sink1 set udp0 [attach-expoo-traffic $n4 $Sink0 200 2s 1s 100k] set udp1 [attach-expoo-traffic $n5 $Sink1 200 2s 1s 200k] $ns at 0.0 "record" $ns at 10.0 "$udp0 start" $ns at 10.0 "$udp1 start" $ns at 90.0 "$udp0 stop" $ns at 95.0 "$udp1 stop" $ns at 100.0 "finish" $ns run plz solve error or tell me how to above error. thank you