help mo phong mang bang ns2

# Create a FAST Tcp connection

proc create_tcp_fast { idx src dst start stop } {

global tcps

global ftps

global ns

global sinks

global tcps_start

global tcps_stop


puts "New TCP connection";

# set source agent and application

set tcps($idx) [new Agent/TCP/Fast]

$tcps($idx) set class_ 2

$tcps($idx) set window_ 100000

$tcps($idx) set alpha_ 200

$tcps($idx) set beta_ 200

$ns attach-agent $src $tcps($idx)

set ftps($idx) [new Application/FTP]

$ftps($idx) attach-agent $tcps($idx)


# set sink

set sinks($idx) [new Agent/TCPSink/Sack1]

$ns attach-agent $dst $sinks($idx)

$ns connect $tcps($idx) $sinks($idx)

set tcps_start($idx) [expr $start]

set tcps_stop($idx) [expr $stop]

$ns at $start "$ftps($idx) start"

$ns at $stop "$ftps($idx) stop"
}


# Record Procedure

proc record {} {

global tcps ntcps

global f0

global queueMoniF queueMoniB

global tcps_start tcps_stop


#get an instance of the simulator

set ns [Simulator instance]

#set the time afterwhich the procedure should be called again

set time 0.005


set now [$ns now]

set queueF [$queueMoniF set pkts_]

set queueB [$queueMoniB set pkts_]


set rate 0


for {set i 0} {$i < $ntcps} {incr i} {

if { ($now > $tcps_start($i)) && ($now < $tcps_stop($i)) } {

set window [expr [$tcps($i) set cwnd_]];

set rtt [expr [$tcps($i) set avgRTT_]];

set bRTT [expr [$tcps($i) set baseRTT_]];

set old_window [expr [$tcps($i) set avg_cwnd_last_RTT_]];

set total_pkt_num [expr [$tcps($i) set t_seqno_]]

if { $rtt > 0 } {

set rate [expr $window/$rtt]
}

if { $bRTT < 9999999 } {

puts $f0 "$i $now $queueF $queueB $rate $window $rtt $bRTT $old_window $total_pkt_num"
}
}
}


# Re-schedule the procedure

$ns at [expr $now+$time] "record"
}

# Define ''finish'' procedure (include post-simulation processes)

proc finish {} {

global ns

global f0

global f_all


$ns flush-trace
close $f_all
close $f0
puts "Finished."
exit 0
}


# ------ SIMULATION SPECIFIC SCRIPT -----------


# The preamble

set ns [new Simulator]

$ns use-scheduler Heap

# Predefine tracing
set Name "fast-test1-record.dat";

set Q1 "fast-test1-queue1.dat";

set Q2 "fast-test1-queue2.dat";

set f0 [open $Name w]

set f1 [open $Q1 w]

set f2 [open $Q2 w]

set f_all [open nstrace.dat w]
#$ns trace-all $f_all


# Define the topology

set Cap 100

set Del 50

set r1 [$ns node]

set r2 [$ns node]

set r3 [$ns node]


$ns duplex-link $r1 $r2 [expr $Cap]Mbps [expr $Del]ms DropTail


set botqF [[$ns link $r1 $r2] queue]

set botqB [[$ns link $r2 $r1] queue]

$ns queue-limit $r1 $r2 2000000;

$ns queue-limit $r2 $r1 2000000;


# Create Sources and Start & Stop times

set ntcps 3;

set SimDuration 100;

create_tcp_fast 0 $r1 $r2 0 100

create_tcp_fast 1 $r1 $r2 20 80

create_tcp_fast 2 $r1 $r2 40 60

#$ns create-connection TCP $r1 TCPSink $r2 1

set starttime 0.0

set finishtime $SimDuration


# Monitor the queue between source switch and destination switch

set queueMoniF [$ns monitor-queue $r1 $r2 $f1 0.1]

set queueMoniB [$ns monitor-queue $r2 $r1 $f2 0.1]


# Run the Simulation

$ns at 0.0 "record"

$ns at $SimDuration "finish"

puts "Simulating $SimDuration Secs."

$ns run

bac nao lam ve mo phong mang theo giao thuc tcp ko ah.em chay cai nay ma no cu bao loi chang the nao sua dc