M.S. RAMAIAH INSTITUTE OF TECHNOLOGY

BANGALORE

(Autonomous Institute, Affiliated to VTU)

Project members:- 

                                             Tanmay Bhargava(1MS13IS133)
                                             Aman Agarwal(1MS13IS010) 

Data Communication Project

To simulate different type of internet traffic such as FTP and TELNET over network and analyze the throughput.

ABSTRACT

In this project we create the nodes using the simulator

ns2 defined by a tcl program.We configure traffic sources and sinks using ns commands.We set 4 nodes and duplex links between them with different transfer rates.In this way we simulate different types of internet traffic FTP,CBR and TELNET over a network.

Acknowledgement

We are very grateful to S.R Manisekhar, Assistant Professor

M.S Ramaiah Institute of Technology, Bangalore for his able

guidance and advice in the development and completion of our Project.

Introduction to NS-2

NS is an event driven network simulator developed at UC Berkeley that simulates variety of IP networks. It implements network protocols such as TCP and UPD, traffic source behavior such as FTP, Telnet, Web, CBR and VBR, router queue management mechanism such as Drop Tail, RED and CBQ, routing algorithms such as Dijkstra, and more. NS also implements multicasting and some of the MAC layer protocols for LAN simulations. The NS project is now a part of the VINT project that develops tools for simulation results display, analysis and converters that convert network topologies generated by well-known generators to NS formats. Currently, NS (version 2) written in C++ and OTcl (Tcl script language with Object-oriented extensions developed at MIT) is available.

This network consists of 4 nodes (n0, n1, n2, n3) as shown in above figure. The duplex links between n0 and n2, and n1 and n2 have 2 Mbps of bandwidth and 10 ms of delay. The duplex link between n2 and n3 has 1.7 Mbps of bandwidth and 20 ms of delay. Each node uses a DropTail queue, of which the maximum size is 10. A "tcp" agent is attached to n0, and a connection is established to a tcp "sink" agent attached to n3. As default, the maximum size of a packet that a "tcp" agent can generate is 1KByte. A tcp "sink" agent generates and sends ACK packets to the sender (tcp agent) and frees the received packets. A "udp" agent that is attached to n1 is connected to a "null" agent attached to n3. A "null" agent just frees the packets received. A "ftp" and a "cbr" traffic generator are attached to "tcp" and "udp" agents respectively, and the "cbr" is configured to generate 1 KByte packets at the rate of 1 Mbps. The "cbr" is set to start at 0.1 sec and stop at 4.5 sec, and "ftp" is set to start at 1.0 sec and stop at 4.0 sec.

TELNET

Telnet is a user command and an underlying TCP/IP protocol for accessing remote computers. Through Telnet, an administrator or another user can access someone else's computer remotely. On the Web, HTTP and FTP protocols allow you to request specific files from remote computers, but not to actually be logged on as a user of that computer. With Telnet, you log on as a regular user with whatever privileges you may have been granted to the specific application and data on that computer.

FTP

Short for File Transfer Protocol, the protocol for exchanging files over the Internet. FTP works in the same way as HTTP for transferring Web pages from a server to a user's browser and SMTP for transferring electronic mail across the Internet in that, like these technologies, FTP uses the Internet's TCP/IP protocols to enable data transfer.
FTP is most commonly used to download a file from a server using the Internet or to upload a file to a server (e.g., uploading a Web page file to a server).

Tcl script for Router handles ftp and telnet traffic simultaneously

Code:

#create Simulator
set ns [new Simulator]

#Open NAM File
set namfile [open ex3.nam w]
$ns namtrace-all $namfile

#Finish Procedure
proc Finish {} {
global ns namfile

#Dump all trace data and close the files
$ns flush-trace
close $namfile

#Execute the nam animation file
exec nam ex3.nam &
exit 0
}

$ns color 1 Blue
$ns color 2 Red

#Create four nodes
set n0 [$ns node]
set n1 [$ns node]
set n2 [$ns node]
set n3 [$ns node]

#Create links between the nodes
$ns duplex-link $n0 $n2 2Mb 10ms DropTail
$ns duplex-link $n1 $n2 2Mb 10ms DropTail
$ns simplex-link $n2 $n3 1Mb 10ms DropTail
$ns simplex-link $n3 $n2 1Mb 10ms DropTail

#Set queue size and Monitor the queue
$ns queue-limit $n0 $n2 10
$ns simplex-link-op $n0 $n2 queuePos 0.5

#Set TCP Connection between n0 and n3
set tcp0 [new Agent/TCP]
$ns attach-agent $n0 $tcp0

set sink0 [new Agent/TCPSink]
$ns attach-agent $n3 $sink0
$ns connect $tcp0 $sink0
$tcp0 set fid_ 1

#Attach FTP Application over TCP
set ftp0 [new Application/FTP]
$ftp0 attach-agent $tcp0
$ftp0 set type_ FTP

#Set TCP Connection between n1 and n3
set tcp1 [new Agent/TCP]
$ns attach-agent $n1 $tcp1
set sink1 [new Agent/TCPSink]
$ns attach-agent $n3 $sink1
$ns connect $tcp1 $sink1
$tcp1 set fid_ 2

#Attach Telnet Application over UDP
set telnet [new Application/Telnet]
$telnet attach-agent $tcp1
$telnet set type_ Telnet

#Schedule Events
$ns at 0.5 "$telnet start"
$ns at 0.5 "$ftp0 start"
$ns at 24.5 "$telnet stop"
$ns at 24.5 "$ftp0 stop"
$ns at 25.0 "Finish"
      
$ns run

 Screenshot: