ns3 如何創建自定義點對點拓撲

Question

創建點對點拓撲涉及兩個節點，生成此類拓撲的代碼如下所示：

// Default Network Topology
//
//       10.1.1.0
// n0 -------------- n1
//    point-to-point
//
 
using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("FirstScriptExample");

int
main (int argc, char *argv[])
{
  CommandLine cmd (__FILE__);
  cmd.Parse (argc, argv);
  
  Time::SetResolution (Time::NS);
  LogComponentEnable ("UdpEchoClientApplication", LOG_LEVEL_INFO);
  LogComponentEnable ("UdpEchoServerApplication", LOG_LEVEL_INFO);

  NodeContainer nodes;
  nodes.Create (2);

  PointToPointHelper pointToPoint;
  pointToPoint.SetDeviceAttribute ("DataRate", StringValue ("5Mbps"));
  pointToPoint.SetChannelAttribute ("Delay", StringValue ("2ms"));

  NetDeviceContainer devices;
  devices = pointToPoint.Install (nodes);

  InternetStackHelper stack;
  stack.Install (nodes);

  Ipv4AddressHelper address;
  address.SetBase ("10.1.1.0", "255.255.255.0");

  Ipv4InterfaceContainer interfaces = address.Assign (devices);

  UdpEchoServerHelper echoServer (9);

  ApplicationContainer serverApps = echoServer.Install (nodes.Get (1));
  serverApps.Start (Seconds (1.0));
  serverApps.Stop (Seconds (10.0));

  UdpEchoClientHelper echoClient (interfaces.GetAddress (1), 9);
  echoClient.SetAttribute ("MaxPackets", UintegerValue (1));
  echoClient.SetAttribute ("Interval", TimeValue (Seconds (1.0)));
  echoClient.SetAttribute ("PacketSize", UintegerValue (1024));

  ApplicationContainer clientApps = echoClient.Install (nodes.Get (0));
  clientApps.Start (Seconds (2.0));
  clientApps.Stop (Seconds (10.0));

  Simulator::Run ();
  Simulator::Destroy ();
  return 0;
}

此代碼僅創建兩個點對點節點。 但是我們如何創建一個具有超過 2 個節點的點對點拓撲，如下圖所示：

Answer 1

PointToPointNetDevices 有幾個布局助手，但沒有一個完全適合您想要做的事情。

實現所需拓撲的最直接方法是創建節點，然后手動安裝 PointToPointNetDevices。 類似的東西

NodeContainer nodes(7);
PointToPointHelper pointToPoint;
NetDeviceContainer devices;

devices.Add(pointToPoint.Install(nodes.Get(0), nodes.Get(1)));
devices.Add(pointToPoint.Install(nodes.Get(0), nodes.Get(2)));
devices.Add(pointToPoint.Install(nodes.Get(1), nodes.Get(3)));
devices.Add(pointToPoint.Install(nodes.Get(2), nodes.Get(3)));
devices.Add(pointToPoint.Install(nodes.Get(2), nodes.Get(4)));
devices.Add(pointToPoint.Install(nodes.Get(2), nodes.Get(6)));
devices.Add(pointToPoint.Install(nodes.Get(4), nodes.Get(6)));
devices.Add(pointToPoint.Install(nodes.Get(5), nodes.Get(5)));

// the rest of your script