ns3—第三章:third.cc分析,带三个子网的网络,wifi,p2p,csma

1.网络结构
这一个网络结构相比与second,多了一个wifi子网。
这里把second的n0变成了一个无线AP
2.程序

/* -*- 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
 */

#include "ns3/core-module.h"
#include "ns3/point-to-point-module.h"
#include "ns3/network-module.h"
#include "ns3/applications-module.h"
#include "ns3/wifi-module.h"
#include "ns3/mobility-module.h"
#include "ns3/csma-module.h"
#include "ns3/internet-module.h"

// Default Network Topology
//
//   Wifi 10.1.3.0
//                 AP
//  *    *    *    *
//  |    |    |    |    10.1.1.0
// n5   n6   n7   n0 -------------- n1   n2   n3   n4
//                   point-to-point  |    |    |    |
//                                   ================
//                                     LAN 10.1.2.0

using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("ThirdScriptExample");

int 
main (int argc, char *argv[])
{
  bool verbose = true;
  uint32_t nCsma = 3;
  uint32_t nWifi = 3;
  bool tracing = false;

  CommandLine cmd;
  cmd.AddValue ("nCsma", "Number of \"extra\" CSMA nodes/devices", nCsma);
  cmd.AddValue ("nWifi", "Number of wifi STA devices", nWifi);
  cmd.AddValue ("verbose", "Tell echo applications to log if true", verbose);
  cmd.AddValue ("tracing", "Enable pcap tracing", tracing);

  cmd.Parse (argc,argv);

  // The underlying restriction of 18 is due to the grid position
  // allocator's configuration; the grid layout will exceed the
  // bounding box if more than 18 nodes are provided.
  if (nWifi > 18)
    {
      std::cout << "nWifi should be 18 or less; otherwise grid layout exceeds the bounding box" << std::endl;
      return 1;
    }

  if (verbose)
    {
      LogComponentEnable ("UdpEchoClientApplication", LOG_LEVEL_INFO);
      LogComponentEnable ("UdpEchoServerApplication", LOG_LEVEL_INFO);
    }
//上面的是一些初始设置,这里进入正式的网络结构
//创建2个P2P节点,并设置信道,安装网卡
  NodeContainer p2pNodes;
  p2pNodes.Create (2);

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

  NetDeviceContainer p2pDevices;
  p2pDevices = pointToPoint.Install (p2pNodes);

//创建4个csma节点,其中一个兼有p2p和csma,并设置信道,安装网卡
  NodeContainer csmaNodes;
  csmaNodes.Add (p2pNodes.Get (1));
  csmaNodes.Create (nCsma);

  CsmaHelper csma;
  csma.SetChannelAttribute ("DataRate", StringValue ("100Mbps"));
  csma.SetChannelAttribute ("Delay", TimeValue (NanoSeconds (6560)));

  NetDeviceContainer csmaDevices;
  csmaDevices = csma.Install (csmaNodes);
  
//创建4个wifi节点,其中一个兼有p2p和wifi,并设置信道,安装网卡
  NodeContainer wifiStaNodes;
  wifiStaNodes.Create (nWifi);
//将p2p第一个节点n0设置为wifi的Ap结点
  NodeContainer wifiApNode = p2pNodes.Get (0);

//配置PHY(物理层)和Channel通道助手
  YansWifiChannelHelper channel = YansWifiChannelHelper::Default ();
  YansWifiPhyHelper phy = YansWifiPhyHelper::Default ();
//把channel和phy关联
  phy.SetChannel (channel.Create ());

//远程基站管理,使用AARF速率控制算法,调节速率,以增加网络速率。
  WifiHelper wifi;
  wifi.SetRemoteStationManager ("ns3::AarfWifiManager");

//配置wifi网络STA网络设备的MAC类型和基础设施网络的SSID
  WifiMacHelper mac;
  Ssid ssid = Ssid ("ns-3-ssid"); //IEEE 802.1服务集标识符对象
  mac.SetType ("ns3::StaWifiMac", //设置为特定种类MAC层,non-AP
               "Ssid", SsidValue (ssid), //设置SSID
               "ActiveProbing", BooleanValue (false)); //设置ActiveProbing,false意味着助手创建的mac将不会发送探测请求。

//为wifi节点安装网路设备
  NetDeviceContainer staDevices;
  staDevices = wifi.Install (phy, mac, wifiStaNodes);

//设置mac层,并为Ap节点安装网络设备
  mac.SetType ("ns3::ApWifiMac",
               "Ssid", SsidValue (ssid));

  NetDeviceContainer apDevices;
  apDevices = wifi.Install (phy, mac, wifiApNode);

//创建移动模型
  MobilityHelper mobility;

  mobility.SetPositionAllocator ("ns3::GridPositionAllocator",
                                 "MinX", DoubleValue (0.0),//起始x坐标
                                 "MinY", DoubleValue (0.0),//起始y坐标
                                 "DeltaX", DoubleValue (5.0),//x轴上节点距离
                                 "DeltaY", DoubleValue (10.0),//y轴上节点距离
                                 "GridWidth", UintegerValue (3),//一行节点最大数量
                                 "LayoutType", StringValue ("RowFirst")//布局类型
);//设置位置分配器

//为wifi移动节点设置移动特性
  mobility.SetMobilityModel ("ns3::RandomWalk2dMobilityModel", 
                             "Bounds", RectangleValue (Rectangle (-50, 50, -50, 50)));   
//移动的一些参数具体解释:“Bounds”,“运动的范围”;“Time”,“走多久换一次方向”,TimeValue (Seconds (1.0));Distance”,"走多远换一次方向"DoubleValue (1.0);“Mode”,“Time or Distance”,EnumValue (RandomWalk2dMobilityModel::MODE_DISTANCE) ;“Direction”,"随机方向 (radians)."StringValue (“ns3::UniformRandomVariable[Min=0.0|Max=6.283184]”);“Speed”“随机速度 (m/s).”,StringValue (“ns3::UniformRandomVariable[Min=2.0|Max=4.0]”)
  mobility.Install (wifiStaNodes);
//为Ap节点设置移动特性
  mobility.SetMobilityModel ("ns3::ConstantPositionMobilityModel");//固定不动
  mobility.Install (wifiApNode);
//安装协议栈
  InternetStackHelper stack;
  stack.Install (csmaNodes);
  stack.Install (wifiApNode);
  stack.Install (wifiStaNodes);

  Ipv4AddressHelper address;
//为每一个网卡分配地址,看着挺多,其实都是重复操作。
  address.SetBase ("10.1.1.0", "255.255.255.0");
  Ipv4InterfaceContainer p2pInterfaces;
  p2pInterfaces = address.Assign (p2pDevices);

  address.SetBase ("10.1.2.0", "255.255.255.0");
  Ipv4InterfaceContainer csmaInterfaces;
  csmaInterfaces = address.Assign (csmaDevices);

  address.SetBase ("10.1.3.0", "255.255.255.0");
  address.Assign (staDevices);
  address.Assign (apDevices);

//服务端设置
  UdpEchoServerHelper echoServer (9);

  ApplicationContainer serverApps = echoServer.Install (csmaNodes.Get (nCsma));
  serverApps.Start (Seconds (1.0));
  serverApps.Stop (Seconds (10.0));
//客户端设置
  UdpEchoClientHelper echoClient (csmaInterfaces.GetAddress (nCsma), 9);
  echoClient.SetAttribute ("MaxPackets", UintegerValue (1));
  echoClient.SetAttribute ("Interval", TimeValue (Seconds (1.0)));
  echoClient.SetAttribute ("PacketSize", UintegerValue (1024));

  ApplicationContainer clientApps = 
    echoClient.Install (wifiStaNodes.Get (nWifi - 1));//将客户端安装在WiFi的倒数第2个节点。
  clientApps.Start (Seconds (2.0));
  clientApps.Stop (Seconds (10.0));
//创建路由
  Ipv4GlobalRoutingHelper::PopulateRoutingTables ();

  Simulator::Stop (Seconds (10.0));

  if (tracing == true)
    {
      pointToPoint.EnablePcapAll ("third");//追踪所有p2p节点的pcap
      phy.EnablePcap ("third", apDevices.Get (0));//追踪ap节点的pcap
      csma.EnablePcap ("third", csmaDevices.Get (0), true);追踪csma的第一个节点的pcap
    }

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

wifi网络结构

ns3—第三章:third.cc分析,带三个子网的网络,wifi,p2p,csma_第1张图片

里面有几个大家非常陌生的配置,这里详细说一下
1)YansWifiPhy
这个代表天线的物理参数,比如 TxGain, RxGain, RxRoiseFigure 等。
从文中也可以看到,我们在使用它时,也用到了channel,这是因为该应用依赖于 YansWifiChannel 中的两个成员变量 PropagationDelayModel (无线电的传播模型,光速c)和 PropagationLossModel(无线电的传播衰减模型)。

你可能感兴趣的:(ns3)