/* -*- 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

//

//         bridge1         The node named bridge1 (node 5 in the nodelist)

//   ------------------        has three CMSA net devices that are bridged

//   CSMA   CSMA   CSMA        together using a BridgeNetDevice.

//     |      |      |

//     |      |      |     The bridge node talks over three CSMA channels

//     |      |      |

//   CSMA   CSMA   CSMA    to three other CSMA net devices

//   ----   ----   ----    

//    n0     n1     n2     Node two acts as a router and talks to another

//                 ----        bridge that connects the remaining nodes.

//                 CSMA

//                   |

//    n3     n4      |

//   ----   ----     |

//   CSMA   CSMA     |

//     |      |      |

//     |      |      |

//     |      |      |

//   CSMA   CSMA   CSMA    The node named bridge2 (node 6 in the nodelist)

//   ------------------        has three CMSA net devices that are bridged

//        bridge2              together using a BridgeNetDevice.

//

// Or, more abstractly, recognizing that bridge 1 and bridge 2 are nodes 

// with three net devices:

//

//        n0     n1                (n0 = 10.1.1.2)

//        |      |                 (n1 = 10.1.1.3)  Note odd addressing

//       -----------               (n2 = 10.1.1.1)

//       | bridge1 | <- n5  

//       -----------

//           |    

//         router    <- n2

//           |

//       -----------

//       | bridge2 | <- n6

//       -----------               (n2 = 10.1.2.1)

//        |      |                 (n3 = 10.1.2.2)

//        n3     n4                (n4 = 10.1.2.3)

//

// So, this example shows two broadcast domains, each interconnected by a bridge

// with a router node (n2) interconnecting the layer-2 broadcast domains

// 

// It is meant to mirror somewhat the csma-bridge example but adds another

// bridged link separated by a router.

// 

// - CBR/UDP flows from n0 (10.1.1.2) to n1 (10.1.1.3) and from n3 (10.1.2.2) to n0 (10.1.1.3)

// - DropTail queues 

// - Global static routing

// - Tracing of queues and packet receptions to file "csma-bridge-one-hop.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"

#include "ns3/bridge-module.h"

using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("CsmaBridgeOneHopExample");

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 ("CsmaBridgeOneHopExample", 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.");

  Ptr<Node> n0 = CreateObject<Node> ();

  Ptr<Node> n1 = CreateObject<Node> ();

  Ptr<Node> n2 = CreateObject<Node> ();

  Ptr<Node> n3 = CreateObject<Node> ();

  Ptr<Node> n4 = CreateObject<Node> ();

  Ptr<Node> bridge1 = CreateObject<Node> ();

  Ptr<Node> bridge2 = CreateObject<Node> ();

  NS_LOG_INFO ("Build Topology");

  CsmaHelper csma;

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

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

  // Create the csma links, from each terminal to the bridge

  // This will create six network devices; we'll keep track separately

  // of the devices on and off the bridge respectively, for later configuration 

  NetDeviceContainer topLanDevices;

  NetDeviceContainer topBridgeDevices;

  // It is easier to iterate the nodes in C++ if we put them into a container

  NodeContainer topLan (n2, n0, n1);

  for (int i = 0; i < 3; i++)

    {

      // install a csma channel between the ith toplan node and the bridge node

      NetDeviceContainer link = csma.Install (NodeContainer (topLan.Get (i), bridge1));

      topLanDevices.Add (link.Get (0));

      topBridgeDevices.Add (link.Get (1));

    }

  //

  // Now, Create the bridge netdevice, which will do the packet switching.  The

  // bridge lives on the node bridge1 and bridges together the topBridgeDevices

  // which are the three CSMA net devices on the node in the diagram above.

  //

  BridgeHelper bridge;

  bridge.Install (bridge1, topBridgeDevices);

  InternetStackHelper internet;

  // Repeat for bottom bridged LAN

  NetDeviceContainer bottomLanDevices;

  NetDeviceContainer bottomBridgeDevices;

  NodeContainer bottomLan (n2, n3, n4);

  for (int i = 0; i < 3; i++)

    {

      NetDeviceContainer link = csma.Install (NodeContainer (bottomLan.Get (i), bridge2));

      bottomLanDevices.Add (link.Get (0));

      bottomBridgeDevices.Add (link.Get (1));

    }

  bridge.Install (bridge2, bottomBridgeDevices);

  // 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");

  ipv4.Assign (topLanDevices);

  ipv4.SetBase ("10.1.2.0", "255.255.255.0");

  ipv4.Assign (bottomLanDevices);

  // 

  // Create router nodes, initialize routing database and set up the routing

  // tables in the nodes.  We excuse the bridge nodes from having to serve as

  // routers, since they don't even have internet stacks on them.

  //

  //

  // 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 (Ipv4Address ("10.1.1.3"), port)));

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

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

  ApplicationContainer app = onoff.Install (n0);

  // 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)));

  ApplicationContainer sink1 = sink.Install (n1);

  sink1.Start (Seconds (1.0));

  sink1.Stop (Seconds (10.0));

  // 

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

  //

  onoff.SetAttribute ("Remote", 

                      AddressValue (InetSocketAddress (Ipv4Address ("10.1.1.2"), port)));

  ApplicationContainer app2 = onoff.Install (n3);

  app2.Start (Seconds (1.1));

  app2.Stop (Seconds (10.0));

  ApplicationContainer sink2 = sink.Install (n0);

  sink2.Start (Seconds (1.1));

  sink2.Stop (Seconds (10.0));

  //

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

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

  //

  NS_LOG_INFO ("Configure Tracing.");

  std::ofstream ascii;

  ascii.open ("csma-bridge-one-hop.tr");

  CsmaHelper::EnableAsciiAll (ascii);

  //

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

  // The output files will be named:

  //     csma-bridge-<nodeId>-<interfaceId>.pcap

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

  // display timestamps correctly)

  //

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

  //

  // Now, do the actual simulation.

  //

  NS_LOG_INFO ("Run Simulation.");

  Simulator::Run ();

  Simulator::Destroy ();

  NS_LOG_INFO ("Done.");

}