Modelling and Simulating FTP traffic - Help Please!

[math...@miamioh.edu]

Hi everyone,

I wanted to model and simulate FTP on csma using NS3. How I did it was by using helper objects of OnOffApplication. Since I am new to the tool, I was wondering if some expert can comment if I am doing it the right way because I cannot see any packet flow when I do a TCP dump. I think I might be doing something wrong when I install application on nodes and I am unable to verify that.

A couple of my expectation were to be able to see TCP ACKs for Tx data pkts and configuring control ports (21 in case of FTP w/ TCP). (I could not find a way to do this..)

Any help is very much appreciated !

Thank You,

-Tushar

My code is as following:

#include "ns3/core-module.h"

#include "ns3/network-module.h"

#include "ns3/internet-module.h"

#include "ns3/point-to-point-module.h"

#include "ns3/applications-module.h"

#include "ns3/csma-module.h"

#include "ns3/ipv4-global-routing-helper.h"

using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("FTP_Sim");

int main(int argc, char *argv[])

{

Time::SetResolution (Time::NS);

LogComponentEnable ("OnOffApplication", LOG_LEVEL_INFO);

  LogComponentEnable ("OnOffApplication", LOG_LEVEL_INFO);

NodeContainer csmaNodes;

csmaNodes.Create(2);

// using csma helper to configure attributes

// and creating connectivity between two nodes

CsmaHelper csma;

// set channel attributes for device

csma.SetChannelAttribute ("DataRate",StringValue("1Mbps"));

csma.SetChannelAttribute ("Delay",StringValue("20ms"));

// installing nodes to create, configure, install devices of required type

NetDeviceContainer csmaDevices;

csmaDevices = csma.Install(csmaNodes);

// installing protocol stack in nodes; once executed will install TCP,UDP, IP etc. on each node of the nodeContainer

InternetStackHelper stack;

stack.Install(csmaNodes);

// assigning IP address to the devices, setting base address here

Ipv4AddressHelper address;

address.SetBase ("10.10.10.0","255.255.255.0");

Ipv4InterfaceContainer csmaInterfaces =address.Assign(csmaDevices);

// assigning ip address to the devices, since devices contain nodes, while ip stack is created within a node

// unint32_t port_num=21; // port number for Rx

Address RxAddress(InetSocketAddress (csmaInterfaces.GetAddress(1), 10)); //Rx obtaining a IPv4 address, and the port number to listen

PacketSinkHelper sinkHelper ("ns3::TcpSocketFactory", RxAddress); // PacketSinkHelper is a class reference for creating socket references and passing address at which Rx is instantiated

ApplicationContainer sinkApp = sinkHelper.Install (csmaNodes.Get(1)); // ApplicationContainer, installs application on the node, in our case it is packet sink helper ; node here is the server node

sinkApp.Start (Seconds (1.0));

sinkApp.Stop (Seconds (10.0));

//creating a TCP transmitter 

// set up address and port number to  send TCP traffic to the server

Address TxAddress(InetSocketAddress(csmaInterfaces.GetAddress(1),10));

OnOffHelper clientHelper ("ns3::TcpSocketFactory", TxAddress);

// setting up attributes for onoff application helper

clientHelper.SetAttribute("DataRate",StringValue("1Mbps"));

clientHelper.SetAttribute("PacketSize",UintegerValue(1280));

ApplicationContainer Tx = clientHelper.Install (csmaNodes.Get (0));

Tx.Start (Seconds (1.0));

    Tx.Stop (Seconds (10.0));

NS_LOG_INFO ("Run Simulation.");

Simulator::Run ();

NS_LOG_INFO ("Done");

csma.EnablePcap("trial",csmaDevices.Get(1),true);

return(0);

}

[Tommaso Pecorella]

Hi,

maybe enabling pcap before running the simulation could help...

T.

[math...@miamioh.edu]

Thanks for your reply Tommaso. It was already enabled. I figured out why I couldn't capture packets. the pcap tracing line of code was placed after simulation run (which was very silly). 

I am still stuck on how can I configure control ports for the FTP. Any help is appreciated.

Thanks!

-Tushar