arp request drop

[Ra]

Hi all,

I am trying to simulate a simple adhoc network and measure the delays. I use the onOff application to generate cbr traffic. When I start all the apps at the same time, the arp packets collide and some of the flows never communicate. I created sample code to highlight this issue. I saw from other threads that this was reported earlier and fixed but I see this again. Could you please let me know what is going wrong?


Thank you.



Output:

...
'build' finished successfully (4.322s)
Simulation Parameters ::
distance     = 2
packetSize     = 80
numFlows    = 5
app Data Rate    = 64kbps

0    5
1    6
2    7
3    8
4    9
arp packet dropped
arp packet dropped
arp packet dropped
arp packet dropped
arp packet dropped
arp packet dropped
arp packet dropped
arp packet dropped
arp packet dropped
arp packet dropped
arp packet dropped
arp packet dropped
arp packet dropped
arp packet dropped
arp packet dropped

flowmon stats

Flow 1 (10.1.1.1 -> 10.1.1.6)
  Tx Pkts:   500
  Rx Pkts:   0
  Tx Bytes:   54000
  Rx Bytes:   0
  Throughput: -0 kbps
 Mean Delay:  -nan
 Mean Jitter: -nan
Flow 2 (10.1.1.2 -> 10.1.1.7)
  Tx Pkts:   500
  Rx Pkts:   0
  Tx Bytes:   54000
  Rx Bytes:   0
  Throughput: -0 kbps
 Mean Delay:  -nan
 Mean Jitter: -nan
Flow 3 (10.1.1.3 -> 10.1.1.8)
  Tx Pkts:   500
  Rx Pkts:   0
  Tx Bytes:   54000
  Rx Bytes:   0
  Throughput: -0 kbps
 Mean Delay:  -nan
 Mean Jitter: -nan
Flow 4 (10.1.1.4 -> 10.1.1.9)
  Tx Pkts:   500
  Rx Pkts:   0
  Tx Bytes:   54000
  Rx Bytes:   0
  Throughput: -0 kbps
 Mean Delay:  -nan
 Mean Jitter: -nan
Flow 5 (10.1.1.5 -> 10.1.1.10)
  Tx Pkts:   500
  Rx Pkts:   0
  Tx Bytes:   54000
  Rx Bytes:   0
  Throughput: -0 kbps
 Mean Delay:  -nan
 Mean Jitter: -nan



Src:
/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2009 University of Washington
 *
 * 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
 *
 */

/*this script is used to used to characterize the throughput and delay of in an
adhoc 802.11 network for different packet sizes and data rates. Since the intent is
to create an adhoc network, there is no routing (or meshing as per my understanding) and
hence a node will be able to communicate with another node if it is in range.*/

#include "ns3/core-module.h"
#include "ns3/network-module.h"
#include "ns3/mobility-module.h"
#include "ns3/config-store-module.h"
#include "ns3/wifi-module.h"
#include "ns3/internet-module.h"
#include "ns3/olsr-helper.h"
#include "ns3/flow-monitor-module.h"
#include "ns3/netanim-module.h"
#include "ns3/applications-module.h"

#include <iostream>
#include <fstream>
#include <vector>
#include <string>

NS_LOG_COMPONENT_DEFINE ("arp-test");

using namespace ns3;


void arpDrop(Ptr <const Packet> pkt){std::cout<<"arp packet dropped"<<std::endl;}

int main (int argc, char *argv[])
{
  double distance = 2;  // m
  uint32_t numFlows = 5;  //
  uint32_t packetSize = 80; // bytes
  char appDataRate[128] = "64kbps";//kbps
  double stopTime = 10.0;
  double delayBinWidth = 0.0001;
  CommandLine cmd;

  cmd.AddValue ("distance", "distance (m)", distance);
  cmd.AddValue ("packetSize", "packet size in Bytes", packetSize);
  cmd.AddValue ("numFlows", "number of flows", numFlows);
  cmd.AddValue ("appDataRate", "appDataRate in kbps", appDataRate);
  cmd.AddValue ("stopTime", "stop time in seconds", stopTime);
  cmd.AddValue ("delayBinWidth", "flowmon histogram delay bin width", delayBinWidth);
  cmd.Parse (argc, argv);
 
  std::cout<<"Simulation Parameters ::" << "\n" <<
    "distance     = "<< distance    << "\n" <<
    "packetSize     = "<< packetSize<< "\n" <<
    "numFlows    = "<< numFlows     << "\n" <<
    "app Data Rate    = "<< appDataRate<<"\n" << std::endl;


  int numNodes = numFlows*2;

  NodeContainer c;
  c.Create (numNodes);
 
  //Config::Set("/NodeList/*/$ns3::ArpL3Protocol/CacheList/*/WaitReplyTimeout",TimeValue(Seconds(0.25)));
  //Config::Set("/NodeList/*/$ns3::ArpL3Protocol/CacheList/*/MaxRetries",UintegerValue(100));

  // The below set of helpers will help us to put together the wifi NICs we want
  WifiHelper wifi;
  wifi.SetStandard(WIFI_PHY_STANDARD_80211b);
  wifi.SetRemoteStationManager ("ns3::ConstantRateWifiManager",
                "DataMode", StringValue("DsssRate2Mbps"),
                "RtsCtsThreshold",UintegerValue(2200));

  YansWifiChannelHelper wifiChannel;
  wifiChannel.SetPropagationDelay ("ns3::ConstantSpeedPropagationDelayModel");
  wifiChannel.AddPropagationLoss ("ns3::FriisPropagationLossModel");
 
  YansWifiPhyHelper wifiPhy =  YansWifiPhyHelper::Default ();
  wifiPhy.Set("TxPowerStart",DoubleValue(0));
  wifiPhy.Set("TxPowerEnd",DoubleValue(0));
  wifiPhy.Set("TxGain",DoubleValue(0));
  wifiPhy.SetChannel (wifiChannel.Create ());

  // Add a non-QoS upper mac, and disable rate control
  NqosWifiMacHelper wifiMac = NqosWifiMacHelper::Default ();
  // Set it to adhoc mode
  wifiMac.SetType ("ns3::AdhocWifiMac");
  NetDeviceContainer devices = wifi.Install (wifiPhy, wifiMac, c);
 
  MobilityHelper mobility;
  mobility.SetPositionAllocator ("ns3::RandomRectanglePositionAllocator",
                "X", StringValue("ns3::UniformRandomVariable[Min=0.0|Max=4.0]"),
                "Y", StringValue("ns3::UniformRandomVariable[Min=0.0|Max=4.0]"));
  mobility.SetMobilityModel ("ns3::ConstantPositionMobilityModel");
  mobility.Install (c);

 
  InternetStackHelper internet;
  internet.Install (c);

  Ipv4AddressHelper ipv4;
  NS_LOG_INFO ("Assign IP Addresses.");
  ipv4.SetBase ("10.1.1.0", "255.255.255.0");
  Ipv4InterfaceContainer ifcont = ipv4.Assign (devices);

  // Create Apps
 
 
  Address* sinkAddress[numNodes];
  OnOffHelper* onOff[numNodes];
  ApplicationContainer onOffApp[numNodes];

  PacketSinkHelper* packetSinkHelper[numNodes];
  ApplicationContainer sinkApApp[numNodes];

  uint16_t portAddr=9;
  uint32_t sinkNodeNum;
 
  for( uint16_t ii =0; ii<numFlows; ii=ii+1){
      sinkNodeNum = ii+numFlows;
      std::cout<<ii<<"\t"<<sinkNodeNum<<std::endl;

      sinkAddress[ii] = new Address(InetSocketAddress(ifcont.GetAddress(sinkNodeNum),portAddr));

      //Install packet sink on node ii
      packetSinkHelper[ii] = new PacketSinkHelper("ns3::UdpSocketFactory", *(sinkAddress[ii]));
      sinkApApp[ii] = (*packetSinkHelper[ii]).Install(c.Get(sinkNodeNum));
      sinkApApp[ii].Start(Seconds(1.0));
      sinkApApp[ii].Stop(Seconds(100.0));


      // Traffic generators
      //Install onOff packet generator on node 0
      onOff[ii] = new OnOffHelper("ns3::UdpSocketFactory",(*sinkAddress[ii]));
      (*onOff[ii]).SetAttribute("OnTime", StringValue("ns3::ConstantRandomVariable[Constant=1.0]"));
      (*onOff[ii]).SetAttribute("OffTime", StringValue("ns3::ConstantRandomVariable[Constant=0]"));
      (*onOff[ii]).SetAttribute("DataRate", StringValue(appDataRate));
      (*onOff[ii]).SetAttribute("PacketSize", UintegerValue(packetSize));
     
      onOffApp[ii] = (*onOff[ii]).Install(c.Get(ii));
     
      (onOffApp[ii]).Start(Seconds(0.0));
      (onOffApp[ii]).Stop(Seconds(stopTime));
  }



  Simulator::Stop (Seconds (stopTime));




 
  //Config::ConnectWithoutContext("/NodeList/*/$ns3::ArpL3Protocol/CacheList/*/Drop", MakeCallback(&arpDrop)); 
  //Config::ConnectWithoutContext("/NodeList/*/$ns3::ArpL3Protocol/Drop", MakeCallback(&arpDrop)); 
  Config::ConnectWithoutContext("/NodeList/*/$ns3::Ipv4L3Protocol/InterfaceList/*/ArpCache/Drop", MakeCallback(&arpDrop)); 


  FlowMonitorHelper flowmon;
  flowmon.SetMonitorAttribute("DelayBinWidth",DoubleValue(delayBinWidth));
  flowmon.SetMonitorAttribute("StartTime",TimeValue(Seconds(5.0)));
  Ptr<FlowMonitor> monitor = flowmon.InstallAll();
 

  Simulator::Run ();

  monitor->CheckForLostPackets();

  Ptr<Ipv4FlowClassifier> classifier = DynamicCast<Ipv4FlowClassifier> (flowmon.GetClassifier ());
  std::map<FlowId, FlowMonitor::FlowStats> stats = monitor->GetFlowStats ();
 
  std::cout<<"\n"<<"flowmon stats"<<"\n"<<std::endl;
  char destAddrFlowMon[32];
  sprintf(destAddrFlowMon,"10.1.1.%d",numNodes);
  Histogram jitterHist;
  //std::ostream os1;
  for (std::map<FlowId, FlowMonitor::FlowStats>::const_iterator i = stats.begin (); i != stats.end (); ++i)
  {
    Ipv4FlowClassifier::FiveTuple t = classifier->FindFlow (i->first);
    if(((t.sourceAddress == Ipv4Address("10.1.1.1")) && (t.destinationAddress == Ipv4Address(destAddrFlowMon))) || 1)
    {
    std::cout << "Flow " << i->first << " (" << t.sourceAddress << " -> " << t.destinationAddress << ")\n";
    std::cout << "  Tx Pkts:   " << i->second.txPackets << "\n";
    std::cout << "  Rx Pkts:   " << i->second.rxPackets << "\n";
    std::cout << "  Tx Bytes:   " << i->second.txBytes << "\n";
    std::cout << "  Rx Bytes:   " << i->second.rxBytes << "\n";
    std::cout << "  Throughput: " << i->second.rxBytes * 8.0 / (i->second.timeLastRxPacket.GetSeconds()-i->second.timeFirstTxPacket.GetSeconds())/ 1024  << " kbps\n";
    std::cout << " Mean Delay:  " << i->second.delaySum.GetSeconds() / i->second.rxPackets << std::endl;
    std::cout << " Mean Jitter: " << i->second.jitterSum.GetSeconds()/ i->second.rxPackets << std::endl;

    }
     
  }

  Simulator::Destroy ();
  return 0;
}

[Konstantinos]

Hi,

The actual fix that was proposed was the use of a random (or just a differentiation, does not have to be random) in the starting times of the applications.

In addition, I see in your code that you start the sink at t=1 and the source at t=0. You will get dropped packets for this 1sec that the source does not 'accept' packets.

[Ravi Teja C]

Thanks Konstantinos.

Please correct me if I am wrong. I think this happens when there is no exponential backoff happening upon ARP pkt collision. Is there a way to turn it on? Or if exp backoff is enabled, then does it have the same contention window size as a regular packet?

Thank you.

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[Konstantinos]

See Bug 187 https://www.nsnam.org/bugzilla/show_bug.cgi?id=187

[Ravi Teja C]

Hi Konstantinos,

I saw that bug earlier but it seemed to be a feature enhancement request to achieve the result of ARQ without doing ARQ. I think this discussion and bug 253 is more relevant to my question.

I used different start times but when there is traffic on the channel, some of the nodes still fail to send ARPs.