Ns3 构建哑铃型拓扑，并实现两个点的TCP连接（详细请戳全文）

如图所示要实现n0到n5的TCP通信

每个链路之间的带宽都是100Mbps

/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */

/*

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#include "ns3/core-module.h"

#include "ns3/network-module.h"

#include "ns3/internet-module.h"

#include "ns3/point-to-point-module.h"

#include "ns3/applications-module.h"

using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("BottleNeckTcpScriptExample");

int

main (int argc, char *argv[])

{

  Time::SetResolution (Time::NS);

  LogComponentEnable ("UdpEchoClientApplication", LOG_LEVEL_INFO);

  LogComponentEnable ("UdpEchoServerApplication", LOG_LEVEL_INFO);

  LogComponentEnable ("BottleNeckTcpScriptExample", LOG_LEVEL_INFO);

 // LogComponentEnable ("TcpL4Protocol", LOG_LEVEL_INFO);

  LogComponentEnable ("PacketSink", LOG_LEVEL_ALL);

  //LogComponentEnable ("OnOff", LOG_LEVEL_ALL);

  NodeContainer nodes;

  nodes.Create ();

  NodeContainer n0n1 = NodeContainer(nodes.Get(),nodes.Get());

  NodeContainer n1n2 = NodeContainer(nodes.Get(),nodes.Get());

  NodeContainer n1n3 = NodeContainer(nodes.Get(),nodes.Get());

  NodeContainer n3n4 = NodeContainer(nodes.Get(),nodes.Get());

  NodeContainer n3n5 = NodeContainer(nodes.Get(),nodes.Get());

  InternetStackHelper internet;

  internet.Install(nodes);

  PointToPointHelper p2p;

  p2p.SetDeviceAttribute("DataRate",StringValue("100Mbps"));

  p2p.SetChannelAttribute("Delay",StringValue("2ms"));

  NetDeviceContainer nets;

  NetDeviceContainer d0d1 =p2p.Install(n0n1);

  NetDeviceContainer d1d2 =p2p.Install(n1n2);

  NetDeviceContainer d1d3 =p2p.Install(n1n3);

  NetDeviceContainer d3d4 =p2p.Install(n3n4);

  NetDeviceContainer d3d5 =p2p.Install(n3n5);

  Ipv4AddressHelper ipv4;

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

  Ipv4InterfaceContainer i0i1 = ipv4.Assign(d0d1);

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

  ipv4.Assign(d1d2);

  ipv4.SetBase("10.1.3.0","255.255.255.0");

  ipv4.Assign(d1d3);

  ipv4.SetBase("10.1.4.0","255.255.255.0");

  ipv4.Assign(d3d4);

  ipv4.SetBase("10.1.5.0","255.255.255.0");

  ipv4.Assign(d3d5);

  Ipv4InterfaceContainer i3i5 = ipv4.Assign(d3d5);

  uint16_t port = ;

  ApplicationContainer sinkApp;

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

  PacketSinkHelper sinkHelper ("ns3::TcpSocketFactory", sinkLocalAddress);

  sinkApp.Add(sinkHelper.Install(nodes.Get()));

  sinkApp.Start (Seconds (0.0));

  sinkApp.Stop (Seconds (10.0));

  OnOffHelper clientHelper ("ns3::TcpSocketFactory", Address ());

  clientHelper.SetAttribute ("OnTime", StringValue ("ns3::ConstantRandomVariable[Constant=1]"));

  clientHelper.SetAttribute ("OffTime", StringValue ("ns3::ConstantRandomVariable[Constant=0]"));

  ApplicationContainer clientApps;

  AddressValue remoteAddress(InetSocketAddress (i0i1.GetAddress (), port));

  clientHelper.SetAttribute("Remote",remoteAddress);

  clientApps.Add(clientHelper.Install(nodes.Get()));

  clientApps.Start(Seconds(1.0));

  clientApps.Stop (Seconds (10.0));

  Ipv4GlobalRoutingHelper::PopulateRoutingTables ();

  //嗅探,记录所有节点相关的数据包

  Simulator::Run ();

  Simulator::Destroy ();

  return ;

}

1.首先针对拓扑的构造，对于这个拓扑构造个人觉得还是相对比较容易，通过对网上一些例子的理解，以及对上次myfirst.cc的理解

可参考 简单ns-3点对点网络的构造

  NodeContainer nodes;

  nodes.Create (6);

  NodeContainer n0n1 = NodeContainer(nodes.Get(0),nodes.Get(1));

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

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

  NodeContainer n3n4 = NodeContainer(nodes.Get(3),nodes.Get(4));

  NodeContainer n3n5 = NodeContainer(nodes.Get(3),nodes.Get(5));

  InternetStackHelper internet;

  internet.Install(nodes);

  PointToPointHelper p2p;

  p2p.SetDeviceAttribute("DataRate",StringValue("100Mbps"));

  p2p.SetChannelAttribute("Delay",StringValue("2ms"));

  NetDeviceContainer nets;

  NetDeviceContainer d0d1 =p2p.Install(n0n1);

  NetDeviceContainer d1d2 =p2p.Install(n1n2);

  NetDeviceContainer d1d3 =p2p.Install(n1n3);

  NetDeviceContainer d3d4 =p2p.Install(n3n4);

  NetDeviceContainer d3d5 =p2p.Install(n3n5);

  Ipv4AddressHelper ipv4;

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

  Ipv4InterfaceContainer i0i1 = ipv4.Assign(d0d1);

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

  ipv4.Assign(d1d2);

  ipv4.SetBase("10.1.3.0","255.255.255.0");

  ipv4.Assign(d1d3);

  ipv4.SetBase("10.1.4.0","255.255.255.0");

  ipv4.Assign(d3d4);

  ipv4.SetBase("10.1.5.0","255.255.255.0");

  ipv4.Assign(d3d5);

  Ipv4InterfaceContainer i3i5 = ipv4.Assign(d3d5);

我的拓扑构建如上面所示，每两个点之间建立点对点链路，数据率100Mbps,信道传输延迟为2ms，然后对每一个网卡（设备），分配IP地址。

这个时候就有一个疑惑，网卡能分配两个以上的IP地址吗，就如上面的节点d1他被分配了10.1.1.2，又被分配了10.1.2.1的IP地址，这时候就想一个网卡能被分配两个以上的IP地址吗，（网络没学好。。） 答案是可以的。

然后再通过Ipv4InterfaceContainer获得等下我们所需的0号节点和5号节点的IP地址，进行TCP连接。

2.接下来是为0号节点装入TCP的sever，为5号节点安装tcp的client的application

  uint16_t port = 50000;

  ApplicationContainer sinkApp;

  Address sinkLocalAddress (InetSocketAddress (Ipv4Address::GetAny (), port)); //获得节点1的IP的地址以及端口号

  PacketSinkHelper sinkHelper ("ns3::TcpSocketFactory", sinkLocalAddress);   //设置为TCP连接

  sinkApp.Add(sinkHelper.Install(nodes.Get(0)));  //把应用程序装入节点0

  sinkApp.Start (Seconds (0.0));

  sinkApp.Stop (Seconds (10.0));

  OnOffHelper clientHelper ("ns3::TcpSocketFactory", Address ());

  clientHelper.SetAttribute ("OnTime", StringValue ("ns3::ConstantRandomVariable[Constant=1]"));

  clientHelper.SetAttribute ("OffTime", StringValue ("ns3::ConstantRandomVariable[Constant=0]"));

  ApplicationContainer clientApps;

  AddressValue remoteAddress(InetSocketAddress (i0i1.GetAddress (0), port));  //设置远端IP以及端口，即服务器应用的IP和端口

  clientHelper.SetAttribute("Remote",remoteAddress);

  clientApps.Add(clientHelper.Install(nodes.Get(5))); //把应用程序装入节点5

  clientApps.Start(Seconds(1.0));

  clientApps.Stop (Seconds (10.0));

这是输出结果：

对于输出结果我存在很大的疑惑，为什么有时候传的是512字节，有时候是536字节，又或是112字节，当然绝大部分以512字节为主。

对于这个问题主要还是自己对TCP连接的原因理解的不够透彻，以及对一些模拟可视化的界面，还没办法弄出来加强理解。

在阅读相关文档后，还是安装TCP应用的地方存在疑惑。 接下来应该学习一些如何操作输出结果，看到可视化的一些东西，以加强对各种数据传输的理解。