set ns [new Simulator] # There are several sources each generating many TCP sessions sharing a bottleneck # link and a single destination. Their number is given by the paramter NodeNb#     S(1) ----- E(1) ----#     .                   |#     .     ---- E(i) ---Core---- Ed -------- D#     .                   |#     S(NodeNb)- E(NodeNb)-set cir0       30000; # policing parameterset cir1       30000; # policing parameterset pktSize    1000set NodeNb       20; # Number of source nodesset NumberFlows 160 ; # Number of flows per source node set sduration   25; # Duration of simulation#Define different colors for data flows (for NAM)$ns color 1 Blue$ns color 2 Red$ns color 3 Green$ns color 4 Brown$ns color 5 Yellow$ns color 6 Black                   set Out [open Out.ns w];   # file containing transfer                            # times of different connectionsset Conn [open Conn.tr w]; # file containing the number of connections set tf   [open out.tr w];  # Open the Trace file$ns trace-all $tf    #Open the NAM trace fileset file2 [open out.nam w]# $ns namtrace-all $file2 # We define three files that will be used to trace the queue size,# the bandwidth and losses at the bottleneck.# defining the topologyset D    [$ns node]set Ed   [$ns node]set Core [$ns node]set flink [$ns simplex-link $Core $Ed 10Mb 1ms dsRED/core]$ns queue-limit  $Core $Ed  100$ns simplex-link $Ed $Core 10Mb 1ms dsRED/edge$ns duplex-link  $Ed   $D  10Mb   0.01ms DropTailfor {set j 1} {$j<=$NodeNb} { incr j } { set S($j) [$ns node] set E($j) [$ns node] $ns duplex-link  $S($j) $E($j)  6Mb   0.01ms DropTail $ns simplex-link $E($j) $Core   6Mb   0.1ms dsRED/edge $ns simplex-link $Core  $E($j)  6Mb   0.1ms dsRED/core $ns queue-limit $S($j) $E($j) 100}#Config Diffservset qEdC    [[$ns link $Ed $Core] queue]$qEdC       meanPktSize 40$qEdC   set numQueues_   1$qEdC    setNumPrec      2for {set j 1} {$j<=$NodeNb} { incr j } { $qEdC addPolicyEntry [$D id] [$S($j) id] TSW2CM 10 $cir0 0.02}$qEdC addPolicerEntry TSW2CM 10 11$qEdC addPHBEntry  10 0 0 $qEdC addPHBEntry  11 0 1 $qEdC configQ 0 0 10 30 0.1$qEdC configQ 0 1 10 30 0.1$qEdC printPolicyTable$qEdC printPolicerTableset qCEd    [[$ns link $Core $Ed] queue]# set qCEd    [$flink queue]$qCEd     meanPktSize $pktSize$qCEd set numQueues_   1$qCEd set NumPrec       2$qCEd addPHBEntry  10 0 0 $qCEd addPHBEntry  11 0 1 $qCEd setMREDMode RIO-D$qCEd configQ 0 0 15 45  0.5 0.01$qCEd configQ 0 1 15 45  0.5 0.01for {set j 1} {$j<=$NodeNb} { incr j } { set qEC($j) [[$ns link $E($j) $Core] queue] $qEC($j) meanPktSize $pktSize $qEC($j) set numQueues_   1 $qEC($j) setNumPrec      2 $qEC($j) addPolicyEntry [$S($j) id] [$D id] TSW2CM 10 $cir1 0.02 $qEC($j) addPolicerEntry TSW2CM 10 11 $qEC($j) addPHBEntry  10 0 0  $qEC($j) addPHBEntry  11 0 1 # $qEC($j) configQ 0 0 20 40 0.02 $qEC($j) configQ 0 0 10 20 0.1 $qEC($j) configQ 0 1 10 20 0.1$qEC($j) printPolicyTable$qEC($j) printPolicerTable  set qCE($j) [[$ns link $Core $E($j)] queue] $qCE($j) meanPktSize      40 $qCE($j) set numQueues_   1 $qCE($j) setNumPrec      2 $qCE($j) addPHBEntry  10 0 0  $qCE($j) addPHBEntry  11 0 1 # $qCE($j) configQ 0 0 20 40 0.02 $qCE($j) configQ 0 0 10 20 0.1 $qCE($j) configQ 0 1 10 20 0.1}# set flow monitorset monfile [open mon.tr w]set fmon [$ns makeflowmon Fid]$ns attach-fmon $flink $fmon$fmon attach $monfile#TCP Sources, destinations, connectionsfor {set i 1} {$i<=$NodeNb} { incr i } {for {set j 1} {$j<=$NumberFlows} { incr j } {set tcpsrc($i,$j) [new Agent/TCP/Newreno]set tcp_snk($i,$j) [new Agent/TCPSink]set k [expr $i*1000 +$j];$tcpsrc($i,$j) set fid_ $k$tcpsrc($i,$j) set window_ 2000$ns attach-agent $S($i) $tcpsrc($i,$j)$ns attach-agent $D $tcp_snk($i,$j)$ns connect $tcpsrc($i,$j) $tcp_snk($i,$j)set ftp($i,$j) [$tcpsrc($i,$j) attach-source FTP]} }# Generators for random size of files. set rng1 [new RNG]$rng1 seed 22# Random inter-arrival times of TCP transfer at each source iset RV [new RandomVariable/Exponential]$RV set avg_ 0.2$RV use-rng $rng1 # Random size of files to transmit set RVSize [new RandomVariable/Pareto]$RVSize set avg_ 10000 $RVSize set shape_ 1.25$RVSize use-rng $rng1# dummy commandset t [$RVSize value]# We now define the beginning times of transfers and the transfer sizes# Arrivals of sessions follow a Poisson process.#for {set i 1} {$i<=$NodeNb} { incr i } {     set t [$ns now]     for {set j 1} {$j<=$NumberFlows} { incr j } {	 # set the beginning time of next transfer from source and attributes	 $tcpsrc($i,$j) set sess $j	 $tcpsrc($i,$j) set node $i	 set t [expr $t + [$RV value]]	 $tcpsrc($i,$j) set starts $t         $tcpsrc($i,$j) set size [expr [$RVSize value]]  $ns at [$tcpsrc($i,$j) set starts] "$ftp($i,$j) send [$tcpsrc($i,$j) set size]"  $ns at [$tcpsrc($i,$j) set starts ] "countFlows $i 1"}}for {set j 1} {$j<=$NodeNb} { incr j } {set Cnts($j) 0}   # The following procedure is called whenever a connection endsAgent/TCP instproc done {} {global tcpsrc NodeNb NumberFlows ns RV ftp Out tcp_snk RVSize # print in $Out: node, session, start time,  end time, duration,      # trans-pkts, transm-bytes, retrans-bytes, throughput     set duration [expr [$ns now] - [$self set starts] ]   set i [$self set node]   set j [$self set sess]   set time [$ns now]   puts $Out "$i \t $j \t $time \t\      $time \t $duration \t [$self set ndatapack_] \t\      [$self set ndatabytes_] \t [$self set  nrexmitbytes_] \t\      [expr [$self set ndatabytes_]/$duration ]"    	  # update the number of flows      countFlows [$self set node] 0}# The following recursive procedure updates the number of connections # as a function of time. Each 0.2 it prints them into $Conn. This# is done by calling the procedure with the "sign" parameter equal# 3 (in which case the "ind" parameter does not play a role). The# procedure is also called by the "done" procedure whenever a connection# from source i ends by assigning the "sign" parameter 0, or when# it begins, by assigning it 1 (i is passed through the "ind" variable).#proc countFlows { ind sign } {global Cnts Conn NodeNbset ns [Simulator instance]      if { $sign==0 } { set Cnts($ind) [expr $Cnts($ind) - 1] } elseif { $sign==1 } { set Cnts($ind) [expr $Cnts($ind) + 1] } else {   puts -nonewline $Conn "[$ns now] \t"  set sum 0  for {set j 1} {$j<=$NodeNb} { incr j } {    puts -nonewline $Conn "$Cnts($j) \t"    set sum [expr $sum + $Cnts($j)]  }  puts $Conn "$sum"  puts $Conn ""  $ns at [expr [$ns now] + 0.2] "countFlows 1 3"puts "in count"} }#Define a 'finish' procedureproc finish {} {        global ns tf file2        $ns flush-trace        close $file2         exit 0}         $ns at 0.5 "countFlows 1 3"$ns at [expr $sduration - 0.01] "$fmon dump"$ns at [expr $sduration - 0.001] "$qCEd printStats"$ns at $sduration "finish"$ns run