/* -*- 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   n2   n3

//       |     |    |    |

//       =================

//              LAN

//

// - UDP flows from n0 to n1 and back

// - DropTail queues 

// - Tracing of queues and packet receptions to file "udp-echo.tr"

#include <fstream>

#include "ns3/core-module.h"

#include "ns3/simulator-module.h"

#include "ns3/helper-module.h"

using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("RealtimeUdpEchoExample");

int 

main (int argc, char *argv[])

{

  //

  // Make the random number generators generate reproducible results.

  //

  RandomVariable::UseGlobalSeed (1, 1, 2, 3, 5, 8);

  //

  // Allow the user to override any of the defaults and the above Bind() at

  // run-time, via command-line arguments

  //

  CommandLine cmd;

  cmd.Parse (argc, argv);

  //

  // But since this is a realtime script, don't allow the user to mess with

  // that.

  //

  GlobalValue::Bind ("SimulatorImplementationType", 

    StringValue ("ns3::RealtimeSimulatorImpl"));

  //

  // Explicitly create the nodes required by the topology (shown above).

  //

  NS_LOG_INFO ("Create nodes.");

  NodeContainer n;

  n.Create (4);

  InternetStackHelper internet;

  internet.Install (n);

  //

  // Explicitly create the channels required by the topology (shown above).

  //

  NS_LOG_INFO ("Create channels.");

  CsmaHelper csma;

  csma.SetChannelAttribute ("DataRate", DataRateValue (DataRate(5000000)));

  csma.SetChannelAttribute ("Delay", TimeValue (MilliSeconds (2)));

  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.");

  Ipv4AddressHelper ipv4;

  ipv4.SetBase ("10.1.1.0", "255.255.255.0");

  Ipv4InterfaceContainer i = ipv4.Assign (d);

  NS_LOG_INFO ("Create Applications.");

  //

  // Create a UdpEchoServer application on node one.

  //

  uint16_t port = 9;  // well-known echo port number

  UdpEchoServerHelper server (port);

  ApplicationContainer apps = server.Install (n.Get(1));

  apps.Start (Seconds (1.0));

  apps.Stop (Seconds (10.0));

  //

  // Create a UdpEchoClient application to send UDP datagrams from node zero to

  // node one.

  //

  uint32_t packetSize = 1024;

  uint32_t maxPacketCount = 500;

  Time interPacketInterval = Seconds (0.01);

  UdpEchoClientHelper client (i.GetAddress (1), port);

  client.SetAttribute ("MaxPackets", UintegerValue (maxPacketCount));

  client.SetAttribute ("Interval", TimeValue (interPacketInterval));

  client.SetAttribute ("PacketSize", UintegerValue (packetSize));

  apps = client.Install (n.Get (0));

  apps.Start (Seconds (2.0));

  apps.Stop (Seconds (10.0));

  std::ofstream ascii;

  ascii.open ("realtime-udp-echo.tr");

  CsmaHelper::EnablePcapAll ("realtime-udp-echo");

  CsmaHelper::EnableAsciiAll (ascii);

  //

  // Now, do the actual simulation.

  //

  NS_LOG_INFO ("Run Simulation.");

  Simulator::Run ();

  Simulator::Destroy ();

  NS_LOG_INFO ("Done.");

}