TCP flow vs TCP flow using vegas

# Experimention :- TCP flow vs TCP flow            
# Experimenter  :- Sivajothy Vanjikumaran 
 
#Create a simulator object
set ns [new Simulator]
#Colors Define
$ns color 1 brown
$ns color 2 green
#Save throughput for the First tcp flow
set f1 [open tcp-tcp-one.tr w]
#Save throughput for the Second tcp flow
set f2 [open tcp-tcp-two.tr w]
#Open the nam trace file
set nf [open tcp-out.nam w]
$ns namtrace-all $nf
#Create nodes
set n0 [$ns node]
set n1 [$ns node]
set n2 [$ns node]
set n3 [$ns node]
set n4 [$ns node]
set n5 [$ns node]
#Links between the nodes
$ns duplex-link $n0 $n2 1Mb 10ms DropTail
$ns duplex-link $n1 $n2 1Mb 10ms DropTail
$ns duplex-link $n3 $n4 1Mb 10ms DropTail
$ns duplex-link $n3 $n5 1Mb 10ms DropTail
# Making a bottle neck connection
$ns duplex-link $n2 $n3 1Mb 10ms DropTail
#
#(0)-             -(4)
#     \         /
#    (2)-----(3)
#     /         \
#(1)-            -(5)
#
#layout of the data transferring path
$ns duplex-link-op $n0 $n2 orient right-down
$ns duplex-link-op $n1 $n2 orient right-up
$ns duplex-link-op $n2 $n3 orient right
$ns duplex-link-op $n3 $n4 orient right-up
$ns duplex-link-op $n3 $n5 orient right-down
#Queue limit between node n2 & n3 (Bottle neck)
$ns queue-limit $n2 $n3 10
#Creation of TCP 1 agent and attach it to node n0
set tcp1 [new Agent/TCP/Vegas]
$ns attach-agent $n0 $tcp1
# Max bound on window size
$tcp1 set window_ 20
# Set flow ID field
$tcp1 set fid_ 1
#Creation of a TCP 2 agent and attach it to node n1
set tcp2 [new Agent/TCP/Vegas]
$ns attach-agent $n1 $tcp2
# max bound on window size
$tcp2 set window_ 20
# set flow ID field
$tcp2 set fid_ 2
#Creation of TCP sinks agents 
set sink1 [new Agent/TCPSink]
set sink2 [new Agent/TCPSink]
#Attach Sinks to nodes
$ns attach-agent $n4 $sink1
$ns attach-agent $n5 $sink2
$ns connect $tcp1 $sink1
$ns connect $tcp2 $sink2
#Creation of FTP applications + attach to agents
set ftp1 [new Application/FTP]
$ftp1 attach-agent $tcp1
set ftp2 [new Application/FTP]
$ftp2 attach-agent $tcp2
#Define a 'finish' procedure
proc finish {} {
 global ns
 $ns flush-trace
 puts "running nam..."
 exec nam -a tcp-out.nam &
 exec xgraph tcp-tcp-one.tr tcp-tcp-two.tr -geometry 800x400+10+10 -x "Time -ms" -y "Throughtput -Kbps" -t "Vanjikumaran's TCP-TCP Experiment" & 
 exit 0
}
proc record {} {
 global sink1 sink2 ns f1 f2
 #Set the time the procedure should be called again
 set time 0.1
 set bw0 [$sink1 set bytes_]
 set bw1 [$sink2 set bytes_]
 #Get the current time
 set now [$ns now]
 # throughtput in Kbps
 puts $f1 "$now [expr ($bw0 * 8) / ($time * 1024)]"
 puts $f2 "$now [expr ($bw1 * 8) / ($time * 1024)]"
 $sink1 set bytes_ 0
 $sink2 set bytes_ 0
 #Call procedure again
 $ns at [expr $now + $time] "record"
}
$ns at 0.0 "record"
$ns at 0.2 "$ftp1 start"
$ns at 0.4 "$ftp2 start"
$ns at 2.0 "$ftp1 stop"
$ns at 2.0 "$ftp2 stop"
$ns at 2.2 "finish"
$ns run