标签：ns3
这一节主要是分析第三个例子 third.cc。 该例子包含了P2P信道，以太信道和WiFi信道。
网络拓扑如下：
// 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
接下来我们来分析一下 third.cc 源码的实现：
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#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"
using namespace ns3;
//声明了一个叫SecondScriptExample的日志构件,可以实现打开或者关闭控制台日志的输出。
NS_LOG_COMPONENT_DEFINE ("ThirdScriptExample");
int main (int argc, char *argv[])
{
//定义变量，用于决定是否开启两个UdpApplication的Logging组件;默认true开启
bool verbose = true;
uint32_t nCsma = 3;
uint32_t nWifi = 3;
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.Parse (argc,argv);
if (nWifi > 18)
{
std::cout << "Number of wifi nodes " << nWifi <<
" specified exceeds the mobility bounding box" << std::endl;
exit (1);
}
if (verbose)
{
LogComponentEnable ("UdpEchoClientApplication", LOG_LEVEL_INFO);
LogComponentEnable ("UdpEchoServerApplication", LOG_LEVEL_INFO);
}
/********************网络拓扑部分************************/
//创建使用P2P链路链接的2个节点
NodeContainer p2pNodes;
p2pNodes.Create (2);
//设置传送速率和信道延迟
PointToPointHelper pointToPoint;
pointToPoint.SetDeviceAttribute ("DataRate", StringValue ("5Mbps"));
pointToPoint.SetChannelAttribute ("Delay", StringValue ("2ms"));
//安装P2P网卡设备到P2P网络节点
NetDeviceContainer p2pDevices;
p2pDevices = pointToPoint.Install (p2pNodes);
//创建NodeContainer类对象，用于总线(CSMA)网络
NodeContainer csmaNodes;
//将第二个P2P节点添加到CSMA的NodeContainer
csmaNodes.Add (p2pNodes.Get (1));
//创建Bus network上另外3个node
csmaNodes.Create (nCsma);
//创建和连接CSMA设备及信道
CsmaHelper csma;
csma.SetChannelAttribute ("DataRate", StringValue ("100Mbps"));
csma.SetChannelAttribute ("Delay", TimeValue (NanoSeconds (6560)));
//安装网卡设备到CSMA信道的网络节点
NetDeviceContainer csmaDevices;
csmaDevices = csma.Install (csmaNodes);
//创建NodeContainer类对象，用于WiFi网络
NodeContainer wifiStaNodes;
wifiStaNodes.Create (nWifi);
//设置WiFi网络的第一个节点为AP
NodeContainer wifiApNode = p2pNodes.Get (0);
//初始化物理信道
YansWifiChannelHelper channel = YansWifiChannelHelper::Default ();
YansWifiPhyHelper phy = YansWifiPhyHelper::Default ();
phy.SetChannel (channel.Create ());
WifiHelper wifi = WifiHelper::Default ();
wifi.SetRemoteStationManager ("ns3::AarfWifiManager");
//Mac层设置
NqosWifiMacHelper mac = NqosWifiMacHelper::Default ();
Ssid ssid = Ssid ("ns-3-ssid");
mac.SetType ("ns3::StaWifiMac",
"Ssid", SsidValue (ssid),
"ActiveProbing", BooleanValue (false));
//安装网卡设备到WiFi信道的网络节点，并配置参数
NetDeviceContainer staDevices;
staDevices = wifi.Install (phy, mac, wifiStaNodes);
mac.SetType ("ns3::ApWifiMac",
"Ssid", SsidValue (ssid));
////安装网卡设备到WiFi信道的AP节点，并配置参数
NetDeviceContainer apDevices;
apDevices = wifi.Install (phy, mac, wifiApNode);
//添加移动模型
MobilityHelper mobility;
mobility.SetPositionAllocator ("ns3::GridPositionAllocator",
"MinX", DoubleValue (0.0),
"MinY", DoubleValue (0.0),
"DeltaX", DoubleValue (5.0),
"DeltaY", DoubleValue (10.0),
"GridWidth", UintegerValue (3),
"LayoutType", StringValue ("RowFirst"));
mobility.SetMobilityModel ("ns3::RandomWalk2dMobilityModel",
"Bounds", RectangleValue (Rectangle (-50, 50, -50, 50)));
//在STA节点上安装移动模型
mobility.Install (wifiStaNodes);
//设置AP：固定在一个位置上
mobility.SetMobilityModel ("ns3::ConstantPositionMobilityModel");
mobility.Install (wifiApNode);
//安装网络协议
InternetStackHelper stack;
stack.Install (csmaNodes);
stack.Install (wifiApNode);
stack.Install (wifiStaNodes);
Ipv4AddressHelper address;
//安排P2P网段的地址
address.SetBase ("10.1.1.0", "255.255.255.0");
Ipv4InterfaceContainer p2pInterfaces;
p2pInterfaces = address.Assign (p2pDevices);
//安排csma网段的地址
address.SetBase ("10.1.2.0", "255.255.255.0");
Ipv4InterfaceContainer csmaInterfaces;
csmaInterfaces = address.Assign (csmaDevices);
//安排wifi网段的地址
address.SetBase ("10.1.3.0", "255.255.255.0");
address.Assign (staDevices);
address.Assign (apDevices);
/********************网络拓扑部分结束*********************/
/**********************应用程序部分*********************/
UdpEchoServerHelper echoServer (9);
//将Server服务安装在CSMA网段的最后一个节点上
ApplicationContainer serverApps = echoServer.Install (csmaNodes.Get (nCsma));
serverApps.Start (Seconds (1.0));
serverApps.Stop (Seconds (10.0));
UdpEchoClientHelper echoClient (csmaInterfaces.GetAddress (nCsma), 9);
echoClient.SetAttribute ("MaxPackets", UintegerValue (1));
echoClient.SetAttribute ("Interval", TimeValue (Seconds (1.0)));
echoClient.SetAttribute ("PacketSize", UintegerValue (1024));
//将Client应用安装在WiFi网段的倒数第二个节点上
ApplicationContainer clientApps =
echoClient.Install (wifiStaNodes.Get (nWifi - 1));
clientApps.Start (Seconds (2.0));
clientApps.Stop (Seconds (10.0));
/****************调用全局路由Helper帮助建立网络路由*******************/
Ipv4GlobalRoutingHelper::PopulateRoutingTables ();
Simulator::Stop (Seconds (10.0));
/****************开启pcap跟踪*******************/
pointToPoint.EnablePcapAll ("third");
phy.EnablePcap ("third", apDevices.Get (0));
csma.EnablePcap ("third", csmaDevices.Get (0), true);
Simulator::Run ();
Simulator::Destroy ();
return 0;
}
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运行结果如下：
注意：
1、YansWifiChannelHelper：
YansWifiPhyHelper共享相同的底层信道,也就是说,它们共享相同的无线介质,可以相互通信。
2、NqosWifiMacHelper
使用NqosWifiMacHelper对象设置MAC参数，表示使用没有QoS保障的Mac层机制。
3、RandomWalk2dMobilityModel
表示在一个边界框中，节点以一个随机的速度在一个随机方向上移动
标签：ns3
原文地址：http://blog.csdn.net/liuruiqun/article/details/45228081
