lavanyasit / ex-12

EX-12 SIMULATION OF TCP USING OPNET SIMULATOR

AIM:

To write a ns2 program for implementing unicast routing protocol.

ALGORITHM:

Step 1: start the program.

Step 2: Declare the global variables ns for creating a new simulator.

Step 3: set the color for packets.

Step 4: open the network animator file in the name of file2 in the write mode.

Step 5: open the trace file in the name of file 1 in the write mode.

Step 6: set the unicast routing protocol to transfer the packets in network.

Step 7: create the required no of nodes.

Step 8: create the duplex-link between the nodes including the delay time,bandwidth and dropping queue mechanism.

Step 9: Give the position for the links between the nodes.

Step 10: set a tcp reno connection for source node.

Step 11: set the destination node using tcp sink.

Step 12: setup a ftp connection over the tcp connection.

Step 13: Down the connection between any nodes at a particular time.

Step 14: Reconnect the downed connection at a particular time.

Step 15: Define the finish procedure. Step 16: in the definition of the finish procedure declare the global variables ns,file1,file2.

Step 17: close the trace file and namefile and execute the network animation file.

Step 18: At the particular time call the finish procedure.

Step 19: stop the program.

PROGRAM:

set ns [new Simulator]

Define different colors for data flows (for NAM)

$ns color 1 Blue $ns color 2 Red

Open the Trace file

set file1 [open out.tr w] $ns trace-all $file1

Open the NAM trace file

set file2 [open out.nam w] $ns namtrace-all $file2

Define a 'finish' procedure

proc finish {} { global ns file1 file2 $ns flush-trace close $file1 close $file2 exec nam out.nam & exit 3 }# Next line should be commented out to have the static routing $ns rtproto DV

Create six nodes

set n0 [$ns node] set n1 [$ns node] set n2 [$ns node] set n4 [$ns node] set n4 [$ns node] set n5 [$ns node]

Create links between the nodes

$ns duplex-link $n0 $n1 0.3Mb 10ms DropTail $ns duplex-link $n1 $n2 0.3Mb 10ms DropTail $ns duplex-link $n2 $n3 0.3Mb 10ms DropTail $ns duplex-link $n1 $n4 0.3Mb 10ms DropTail $ns duplex-link $n3 $n5 0.5Mb 10ms DropTail $ns duplex-link $n4 $n5 0.5Mb 10ms DropTail

Give node position (for NAM)

$ns duplex-link-op $n0 $n1 orient right $ns duplex-link-op $n1 $n2 orient right $ns duplex-link-op $n2 $n3 orient up $ns duplex-link-op $n1 $n4 orient up-left $ns duplex-link-op $n3 $n5 orient left-up $ns duplex-link-op $n4 $n5 orient right-up

Setup a TCP connection

set tcp [new Agent/TCP/Newreno] $ns attach-agent $n0 $tcp set sink [new Agent/TCPSink/DelAck] $ns attach-agent $n5 $sink $ns connect $tcp $sink $tcp set fid_ 1

Setup a FTP over TCP connection

set ftp [new Application/FTP] $ftp attach-agent $tcp $ftp set type_ FTP $ns rtmodel-at 1.0 down $n1 $n4 $ns rtmodel-at 4.5 up $n1 $n4 $ns at 0.1 "$ftp start" $ns at 6.0 "finish" $ns run