Description:

     This network consists of 4 nodes (Client1, Client2, Router1, Router2 and Endserver1).The duplex links between Client1 Client2 and Router1have 5 Mbps of bandwidth and 50 ms of delay. The duplex link between Router1 and Router2 has 150Kbps of bandwidth and 50 ms of delay. The duplex link between Router2 and Endserver1 has 300Kbps of bandwidth and 50 ms of delay. Each link uses a Drop Tail queue. A "TCP" agent is attached to Client1, and Client2 connection is established to a "TCPSink" agent attached to Endserver1 and E. As default, the maximum size of a packet that a "TCP" agent can generate is 1000bytes. A "TCPSink" agent generates and sends ACK packets to the sender (tcp agent) and frees the received packets. The ftp is set to start at 0.5 sec and stop at 5.5 sec. Here we generate the rand file. It is used to create a graph to identify the how many data were sent, how many data were dropped and so on...

File name: “Rands1.tcl”

#-------Event scheduler object creation--------#

set ns [new Simulator]

#--------creating nam----#

set nf [open Rands1.nam w]
$ns namtrace-all $nf

set nt [open Rands1.tr w]
$ns trace-all $nt

#------------COLOR DESCRIPTION---------------#

set proto rlm
$ns color 1 red
$ns color 2 cgyan

# --------- CREATING SENDER - RECEIVER - ROUTER NODES-----------#

set Client1 [$ns node]
set Client2 [$ns node]
set Router1 [$ns node]
set Router2 [$ns node]
set Endserver1 [$ns node]

# --------------CREATING DUPLEX LINK -----------------------#

$ns duplex-link $Client1 $Router1 5Mb 50ms DropTail
$ns duplex-link $Client2 $Router1 5Mb 50ms DropTail
$ns duplex-link $Router1 $Router2 150Kb 50ms DropTail
$ns duplex-link $Router2 $Endserver1 300Kb 50ms DropTail

#-----------CREATING ORIENTATION -------------------------#

$ns duplex-link-op $Client1 $Router1 orient down-right
$ns duplex-link-op $Client2 $Router1 orient right
$ns duplex-link-op $Router1 $Router2 orient right
$ns duplex-link-op $Router2 $Endserver1 orient up

# --------------LABELLING -----------------------------#

$ns at 0.0 "$Client1 label Client1"
$ns at 0.0 "$Client2 label Client2"
$ns at 0.0 "$Router1 label Router1"
$ns at 0.0 "$Router2 label Router2"
$ns at 0.0 "$Endserver1 label Endserver1"

# --------------- CONFIGURING NODES -----------------#

$Endserver1 shape hexagon
$Router1 shape square
$Router2 shape square

# ----------------QUEUES POSITIONING AND ESTABLISHMENT -------------#

$ns duplex-link-op $Client1 $Router1 queuePos 0.1
$ns duplex-link-op $Client2 $Router1 queuePos 0.1
$ns duplex-link-op $Router1 $Router2 queuePos 0.5
$ns duplex-link-op $Router2 $Endserver1 queuePos 0.5

# ----------------ESTABLISHING COMMUNICATION -------------#
           
#--------------TCP CONNECTION BETWEEN NODES---------------#

set tcp0 [new Agent/TCP]
$tcp0 set maxcwnd_ 16
$tcp0 set fid_ 1
$ns attach-agent $Client1 $tcp0

set sink0 [new Agent/TCPSink]
$ns attach-agent $Endserver1 $sink0

$ns connect $tcp0 $sink0

set ftp0 [new Application/FTP]
$ftp0 attach-agent $tcp0

$ns add-agent-trace $tcp0 tcp
$tcp0 tracevar cwnd_

$ns at 0.5 "$ftp0 start"
$ns at 5.5 "$ftp0 stop"
#---------------------------------------#

set tcp1 [new Agent/TCP]
$tcp1 set maxcwnd_ 16
$tcp1 set fid_ 2
$ns attach-agent $Client2 $tcp1

set sink1 [new Agent/TCPSink]
$ns attach-agent $Endserver1 $sink1

$ns connect $tcp1 $sink1

set ftp1 [new Application/FTP]
$ftp1 attach-agent $tcp1

$ns add-agent-trace $tcp1 tcp
$tcp1 tracevar cwnd_

$ns at 0.5 "$ftp1 start"
$ns at 6.5 "$ftp1 stop"

$ns rtmodel-at 2.88 down $Router1 $Router2
$ns rtmodel-at 3.52 up $Router2 $Endserver1

$ns at 1.1025 "$ns trace-annotate \"Time: 1.1025 Pkt Transfer Path thru node_(1)..\""
$ns at 2.88 "$ns trace-annotate \"Time: 2.88 node_(3) drop and block pkt transfer..\""
$ns at 5.1936 "$ns trace-annotate \"Time: 5.1936 Pkt Transfer Path thru node_(1)..\""

      # ---------------- FINISH PROCEDURE -------------#

proc finish {} {
 
 global ns nf nt
set PERL "/bin/perl5.8.2"
               set NSHOME "/home/ns-allinone-2.30"  ;#change path
               set XGRAPH "$NSHOME/bin/xgraph"
               set SETFID "$NSHOME/ns-2.30/bin/set_flow_id"
               set RAW2XG_SCTP "$NSHOME/ns-2.30/bin/raw2xg-sctp"
               $ns flush-trace
               close $nf
               exec $PERL $SETFID -s Rands1.tr | \
               $PERL $RAW2XG_SCTP -A -q > Rands1.rands
               exec $XGRAPH -bb -tk -nl -m -x time -y packets Rands1.rands &
 $ns flush-trace
 close $nf
 puts "running nam..."
 exit 0
 }

#Calling finish procedure
$ns at 7.0 "finish"
$ns run

#-----How to run-----#

$ns rands1.tcl
       Or
$xgraph rands1.rands

#----------Snapshot-----------#