Applications in NS-3

Command Line Arguments

• 아래와 같이 script를 수정해서 command line으로 argument를 입력받을 수 있음

uint32_t max_packets = 1;
std::string delay = "2ms";
CommandLine cmd;
cmd.AddValue("howmany", "Number of packets to echo", max_packets);
cmd.AddValue("delay", "Link Delay", delay);
cmd.Parse (argc, argv);
// ...
pointToPoint.SetChannelAttribute ("Delay", String Value (delay));
// ...
echoClient.SetAttribute ("MaxPackets", UintegerValue (max_packets));

• 아래의 명령어 형식으로 simulation 실행

./waf --run "scratch/myfirst --howmany=2 --delay=10ms"

Tracing System

• Generating output after running a simulation
• • Checking the operation
• • Measuring the system performance
• Trace source: Signaling events and providing access to interesting data (provider)
• Trace sink: Consuming trace information (consumer)

PCAP tracing (Packet CAPture)

• .pcap file format
• Traffice trace analyze
• Put the following code at the end of the file

pointToPoint.EnablePcapAll("firstcap");

Simulator::Run ();
Simulator::Destroy ();
return 0;

• Result is locate at ns-3.29

./firstcap-1-0.pcap
./firstcap-0-0.pcap

• Reading output using tcpdump
  

tcpdump -nn -tt -r firstcap-0-0.pcap

Applications in ns-3

• An Application generates packets
• Applications are associated with individual nodes
• Class ns3::Application can be used as a base class for ns3 applications

UdpClientServer

• Applications
• • UdpClient
• • UdpServer
• Application Helpers
• • UdpClientHelper
• • UdpServerHelper

Attributes for UdpClient

• Interval: The time to wait between pakcets
• RemoteAddress: The destination of the outbound packets
• RemotePort: The destination port of the outbound packets

Attributes for UdpServer

• Port: Port on which we listen for incoming packets
• PacketWindowSize: The size of the window used to compute the packet loss

Functions for Application

• void Application::SetStartTime(Time time);
• void ApplicationContainer::Start(Time start);
• void Application::SetStopTime(Time time);
• void ApplicationContainer::Stop(Time stop);
• virtual void Application::StartApplication(void);
• virtual void Application::StopApplication(void);

UDP Udpclientserverapplication

• 참고) ./ns-allinone-3.29/ns-3.29/examples에 예제 코드 있음
• p2p link: DataRate 10Mbps, Delay 10us (Command Line Arguments, DataRate, Delay)
• Application & flow
• • udp-client-server Application (No echo from server)
• • Packet Size: 1024 Bytes
• • UDP flow: node0 -> node1, App. Transmit. Speed: 1Mbps, 1 - 10s
• Generate .pcap file using PCAP trace
• Check .pcap file with TCPDUMP or Wireshark

/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

// Network topology
//
//       n0    n1
//       |     |
//       =======
//         LAN
//
// - UDP flows from n0 to n1

#include <fstream>
#include "ns3/core-module.h"
#include "ns3/csma-module.h"
#include "ns3/applications-module.h"
#include "ns3/internet-module.h"

using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("UdpClientServerExample");

int
main (int argc, char *argv[])
{
//
// Enable logging for UdpClient and
//
  LogComponentEnable ("UdpClient", LOG_LEVEL_INFO);
  LogComponentEnable ("UdpServer", LOG_LEVEL_INFO);

  bool useV6 = false;
  Address serverAddress;

  uint64_t datarate = 10000000; //10Mbps
  uint32_t delay = 0.01; //10us

  CommandLine cmd;
  //cmd.AddValue ("useIpv6", "Use Ipv6", useV6);
  cmd.AddValue ("DataRate", "DataRate", datarate);
  cmd.AddValue ("Delay", "Delay", delay);
  cmd.Parse (argc, argv);

//
// Explicitly create the nodes required by the topology (shown above).
//
  NS_LOG_INFO ("Create nodes.");
  NodeContainer n;
  n.Create (2);

  InternetStackHelper internet;
  internet.Install (n);

  NS_LOG_INFO ("Create channels.");
//
// Explicitly create the channels required by the topology (shown above).
//
  CsmaHelper csma;
  //csma.SetChannelAttribute ("DataRate", DataRateValue (DataRate (5000000)));
  //csma.SetChannelAttribute ("Delay", TimeValue (MilliSeconds (2)));
  csma.SetChannelAttribute ("DataRate", DataRateValue (DataRate (datarate)));
  csma.SetChannelAttribute ("Delay", TimeValue (MilliSeconds (delay)));
  csma.SetDeviceAttribute ("Mtu", UintegerValue (1400));
  NetDeviceContainer d = csma.Install (n);

//
// We've got the "hardware" in place.  Now we need to add IP addresses.
//
  NS_LOG_INFO ("Assign IP Addresses.");
  if (useV6 == false)
    {
      Ipv4AddressHelper ipv4;
      ipv4.SetBase ("10.1.1.0", "255.255.255.0");
      Ipv4InterfaceContainer i = ipv4.Assign (d);
      serverAddress = Address (i.GetAddress (1));
    }
  else
    {
      Ipv6AddressHelper ipv6;
      ipv6.SetBase ("2001:0000:f00d:cafe::", Ipv6Prefix (64));
      Ipv6InterfaceContainer i6 = ipv6.Assign (d);
      serverAddress = Address(i6.GetAddress (1,1));
    }

  NS_LOG_INFO ("Create Applications.");
//
// Create one udpServer applications on node one.
//
  uint16_t port = 4000;
  UdpServerHelper server (port);
  ApplicationContainer apps = server.Install (n.Get (1));
  apps.Start (Seconds (1.0));
  apps.Stop (Seconds (10.0));

//
// Create one UdpClient application to send UDP datagrams from node zero to
// node one.
//
  uint32_t MaxPacketSize = 1024;
  Time interPacketInterval = Seconds (0.05);
  uint32_t maxPacketCount = 320;
  UdpClientHelper client (serverAddress, port);
  client.SetAttribute ("MaxPackets", UintegerValue (maxPacketCount));
  client.SetAttribute ("Interval", TimeValue (interPacketInterval));
  client.SetAttribute ("PacketSize", UintegerValue (MaxPacketSize));
  apps = client.Install (n.Get (0));
  apps.Start (Seconds (2.0));
  apps.Stop (Seconds (10.0));
  
  csma.EnablePcapAll("2019315447");
//
// Now, do the actual simulation.
//
  NS_LOG_INFO ("Run Simulation.");
  Simulator::Run ();
  Simulator::Destroy ();
  NS_LOG_INFO ("Done.");
}

• uint64_t 형식으로 datarate 정의
• uint32_t 형식으로 delay 정의
• datarate와 delay를 "DataRate", "Delay"로 command line으로 입력 받도록 설정함
• csma.EnablePcapAll();으로 .pcap 파일 생성하도록 함
• 아래의 명령어로 simulator 실행

./waf --run "scratch/week4_homework --DataRate=10000000 --Delay=0.01"

• 생성된 .pcap 파일 확인