/* -*- 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

//     \ 5 Mb/s, 2ms

//      \          1.5Mb/s, 10ms

//       n2 ------------------------n3

//      /                          /

//     / 5 Mb/s, 2ms              /

//   n1--------------------------

//          1.5 Mb/s, 100ms

//

// this is a modification of simple-global-routing to allow for

// a single hop but higher-cost path between n1 and n3

// 

// - Tracing of queues and packet receptions to file "simple-rerouting.tr"

#include <iostream>

#include <fstream>

#include <string>

#include <cassert>

#include "ns3/core-module.h"

#include "ns3/simulator-module.h"

#include "ns3/helper-module.h"

#include "ns3/global-route-manager.h"

using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("SimpleAlternateRoutingExample");

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("GlobalRouteManager", LOG_LOGIC);

  LogComponentEnable("GlobalRouter", LOG_LOGIC);

#endif

  //

  // Make the random number generators generate reproducible results.

  //

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

  Config::SetDefault ("ns3::OnOffApplication::PacketSize", Uinteger (210));

  Config::SetDefault ("ns3::OnOffApplication::DataRate", DataRate ("300b/s"));

  // The below metric, if set to 3 or higher, will cause packets between

  // n1 and n3 to take the 2-hop route through n2

  CommandLine cmd;

  // 

  // Additionally, we plumb this metric into the default value / command 

  // line argument system as well, for exemplary purposes.  This means 

  // that it can be resettable at the command-line to the program, 

  // rather than recompiling

  // e.g. waf --run "simple-alternate-routing --AlternateCost=5"

  uint16_t sampleMetric = 1;

  cmd.AddValue ("AlternateCost",

                "This metric is used in the example script between n3 and n1 ", 

                sampleMetric);

  // Allow the user to override any of the defaults and the above

  // DefaultValue::Bind ()s at run-time, via command-line arguments

  cmd.Parse (argc, argv);

  // Here, we will explicitly create four nodes.  In more sophisticated

  // topologies, we could configure a node factory.

  NS_LOG_INFO ("Create nodes.");

  NodeContainer c;

  c.Create (4);

  NodeContainer n0n2 = NodeContainer (c.Get (0), c.Get (2));

  NodeContainer n1n2 = NodeContainer (c.Get (1), c.Get (2));

  NodeContainer n3n2 = NodeContainer (c.Get (3), c.Get (2));

  NodeContainer n1n3 = NodeContainer (c.Get (1), c.Get (3));

  // We create the channels first without any IP addressing information

  NS_LOG_INFO ("Create channels.");

  PointToPointHelper p2p;

  p2p.SetChannelParameter ("BitRate", DataRate (5000000));

  p2p.SetChannelParameter ("Delay", MilliSeconds (2));

  NetDeviceContainer d0d2 = p2p.Install (n0n2);

  NetDeviceContainer d1d2 = p2p.Install (n1n2);

  p2p.SetChannelParameter ("BitRate", DataRate(1500000));

  p2p.SetChannelParameter ("Delay", MilliSeconds (10));

  NetDeviceContainer d3d2 = p2p.Install (n3n2);

  p2p.SetChannelParameter ("Delay", MilliSeconds (100));

  NetDeviceContainer d1d3 = p2p.Install (n1n3);

  InternetStackHelper internet;

  internet.Install (c);

  // Later, we add IP addresses.  The middle two octets correspond to 

 // the channel number.  

  NS_LOG_INFO ("Assign IP Addresses.");

  Ipv4AddressHelper ipv4;

  ipv4.SetBase ("10.0.0.0", "255.255.255.0");

  ipv4.Assign (d0d2);

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

  Ipv4InterfaceContainer i1i2 = ipv4.Assign (d1d2);

  ipv4.SetBase ("10.2.2.0", "255.255.255.0");

  ipv4.Assign (d3d2);

  ipv4.SetBase ("10.3.3.0", "255.255.255.0");

  Ipv4InterfaceContainer i1i3 = ipv4.Assign (d1d3);

  i1i3.SetMetric (0, sampleMetric);

  i1i3.SetMetric (1, sampleMetric);

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

  // tables in the nodes.

  GlobalRouteManager::PopulateRoutingTables ();

  // Create the OnOff application to send UDP datagrams 

  NS_LOG_INFO ("Create Application.");

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

  // Create a flow from n3 to n1, starting at time 1.1 seconds

  OnOffHelper onoff;

  onoff.SetAppAttribute ("OnTime", ConstantVariable (1));

  onoff.SetAppAttribute ("OffTime", ConstantVariable (0));

  onoff.SetUdpRemote (i1i2.GetAddress (0), port);

  ApplicationContainer apps = onoff.Install (c.Get (3));

  apps.Start (Seconds (1.1));

  apps.Start (Seconds (10.0));

  // Create a packet sink to receive these packets

  PacketSinkHelper sink;

  apps = sink.Install (c.Get (1));

  apps.Start (Seconds (1.1));

  apps.Stop (Seconds (10.0));

  std::ofstream ascii;

  ascii.open ("simple-alternate-routing.tr");

  PointToPointHelper::EnablePcap ("simple-alternate-routing");

  PointToPointHelper::EnableAscii (ascii);

  NS_LOG_INFO ("Run Simulation.");

  Simulator::Run ();

  Simulator::Destroy ();

  NS_LOG_INFO ("Done.");

  return 0;

}