/* -*- 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

//

// - CBR/UDP flows from n0 to n1 and from n3 to n0

// - DropTail queues 

// - Tracing of queues and packet receptions to file "csma-one-subnet.tr"

#include <iostream>

#include <fstream>

#include "ns3/simulator-module.h"

#include "ns3/node-module.h"

#include "ns3/core-module.h"

#include "ns3/helper-module.h"

using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("CsmaOneSubnetExample");

int 

main (int argc, char *argv[])

{

//

// Users may find it convenient to turn on explicit debugging

// for selected modules; the below lines suggest how to do this

//

#if 0 

  LogComponentEnable ("CsmaOneSubnetExample", LOG_LEVEL_INFO);

#endif

//

// 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);

//

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

//

  NS_LOG_INFO ("Create nodes.");

  NodeContainer nodes;

  nodes.Create (4);

  NS_LOG_INFO ("Build Topology");

  CsmaHelper csma;

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

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

//

// Now fill out the topology by creating the net devices required to connect

// the nodes to the channels and hooking them up.

//

  NetDeviceContainer devices = csma.Install (nodes);

  InternetStackHelper internet;

  internet.Install (nodes);

// 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 interfaces = ipv4.Assign (devices);

//

// Create an OnOff application to send UDP datagrams from node zero to node 1.

//

  NS_LOG_INFO ("Create Applications.");

  uint16_t port = 9;   // Discard port (RFC 863)

  OnOffHelper onoff ("ns3::UdpSocketFactory", 

                     Address (InetSocketAddress (interfaces.GetAddress (1), port)));

  onoff.SetAttribute ("OnTime", RandomVariableValue (ConstantVariable (1)));

  onoff.SetAttribute ("OffTime", RandomVariableValue (ConstantVariable (0)));

  ApplicationContainer app = onoff.Install (nodes.Get (0));

  // Start the application

  app.Start (Seconds (1.0));

  app.Stop (Seconds (10.0));

  // Create an optional packet sink to receive these packets

  PacketSinkHelper sink ("ns3::UdpSocketFactory",

    Address (InetSocketAddress (Ipv4Address::GetAny (), port)));

  app = sink.Install (nodes.Get (1));

  app.Start (Seconds (0.0));

// 

// Create a similar flow from n3 to n0, starting at time 1.1 seconds

//

  onoff.SetAttribute ("Remote", 

                      AddressValue (InetSocketAddress (interfaces.GetAddress (0), port)));

  app = onoff.Install (nodes.Get (3));

  app.Start(Seconds (1.1));

  app.Stop (Seconds (10.0));

  app = sink.Install (nodes.Get (0));

  app.Start (Seconds (0.0));

//

// Configure tracing of all enqueue, dequeue, and NetDevice receive events.

// Trace output will be sent to the file "csma-one-subnet.tr"

//

  NS_LOG_INFO ("Configure Tracing.");

  std::ofstream ascii;

  ascii.open ("csma-one-subnet.tr", std::ios_base::binary | std::ios_base::out);

  CsmaHelper::EnableAsciiAll (ascii);

//

// Also configure some tcpdump traces; each interface will be traced.

// The output files will be named:

//     csma-one-subnet-<nodeId>-<interfaceId>.pcap

// and can be read by the "tcpdump -r" command (use "-tt" option to

// display timestamps correctly)

//

  CsmaHelper::EnablePcapAll ("csma-one-subnet", false);

//

// Now, do the actual simulation.

//

  NS_LOG_INFO ("Run Simulation.");

  Simulator::Run ();

  Simulator::Destroy ();

  NS_LOG_INFO ("Done.");

}