ns3的入门教程<2>(数据网络技术实验)
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ns3的入门教程<2>
前言
接着上一次的报告继续,实现总线结构网络环境进行仿真
一、硬件实现
在硬件实现方面需要看下在ns3文件夹下的 /usr/local/workspace/ns-allinone-3.28.1/ns-3.28.1/examples/tutorial文夹下的文件,下面有:
first.cc, second.cc, third.cc,等文件,可以很好对ns3的硬件仿真有很好的认识。,我在这里就不再过多的阐述了,直接上总线结构的仿真代码,并进行分析。
#include "ns3/core-module.h"
#include "ns3/network-module.h"
#include "ns3/csma-module.h"
#include "ns3/internet-module.h"
#include "ns3/point-to-point-module.h"
#include "ns3/applications-module.h"
#include "ns3/ipv4-global-routing-helper.h"
#include "ns3/netanim-module.h"
#include "ns3/flow-monitor-module.h"
#include "ns3/packet-sink.h"
// Default Network Topology
// 10.1.1.0
// n0 n1 n2 n3 n4 n5 n6 n7 n8
// | | | | | | | | |
// ==========================================
// LAN
//
// CSMA networks,only n0 as client , n8 as server based on UDP pro
using namespace ns3;
int
main (int argc, char *argv[])
{
bool verbose = true;
uint32_t nCsma = 8; //设置通信节点的数量,共8个通信节点
CommandLine cmd;
cmd.AddValue ("nCsma", "Number of \"extra\" CSMA nodes/devices", nCsma);
cmd.AddValue ("verbose", "Tell echo applications to log if true", verbose);
cmd.Parse (argc,argv);
nCsma = nCsma == 0 ? 1 : nCsma;
//创建通信节点,共8个通信节点
NodeContainer csmaNodes;
csmaNodes.Create (nCsma);
//创建总线信道,信道的带宽为10Mbps,信道延迟为2ms
CsmaHelper csma;
csma.SetChannelAttribute ("DataRate", StringValue ("10Mbps"));
csma.SetChannelAttribute ("Delay", StringValue ("2ms"));
csma.SetDeviceAttribute ("EncapsulationMode", StringValue ("Llc"));
//在所有创建的节点上安装通信设备
NetDeviceContainer csmaDevices;
csmaDevices = csma.Install (csmaNodes);
//在所有创建的节点上安装通信协议栈
InternetStackHelper stack;
stack.Install (csmaNodes);
//给所有创建的节点分配IP地址
Ipv4AddressHelper address;
address.SetBase ("10.1.1.0", "255.255.255.0");
Ipv4InterfaceContainer csmaInterfaces;
csmaInterfaces = address.Assign (csmaDevices);
}
到此,基于总线结构的网络仿真已经实现到网络层,只需要在其上添加其传输层的协议,就可以实现网络仿真。
二、通信实现
1.传输层UDP通信实现
uint16_t port = 9; // Discard port (RFC 863)
// Create a similar flow from n0 to n7, starting at time 1.0 seconds
//这里的IP地址是指定收的节点的IP地址
OnOffHelper onoff ("ns3::UdpSocketFactory",
Address (InetSocketAddress (Ipv4Address ("10.1.1.8"), port)));
onoff.SetConstantRate (DataRate ("4Mb/s")); //set node datarate
ApplicationContainer app = onoff.Install (csmaNodes.Get (0));
// Start the application
app.Start (Seconds (1.0));
app.Stop (Seconds (10.0));
// Create an optional packet sink to receive these packets
PacketSinkHelper sink ("ns3::UdpSocketFactory",
Address (InetSocketAddress (Ipv4Address::GetAny (), port)));
app = sink.Install (csmaNodes.Get (7));
app.Start (Seconds (0.0));
// Create a similar flow from n1 to n6, starting at time 1.0 seconds
onoff.SetAttribute ("Remote",
AddressValue (InetSocketAddress (Ipv4Address ("10.1.1.7"), port)));
app = onoff.Install (csmaNodes.Get (1));
app.Start (Seconds (1));
app.Stop (Seconds (10.0));
app = sink.Install (csmaNodes.Get (6));
app.Start (Seconds (0.0));
// Create a similar flow from n2 to n5, starting at time 1.0 seconds
onoff.SetAttribute ("Remote",
AddressValue (InetSocketAddress (Ipv4Address ("10.1.1.6"), port)));
app = onoff.Install (csmaNodes.Get (2));
app.Start (Seconds (1));
app.Stop (Seconds (10.0));
app = sink.Install (csmaNodes.Get (5));
app.Start (Seconds (0.0));
// Create a similar flow from n3 to n4, starting at time 1.0 seconds
onoff.SetAttribute ("Remote",
AddressValue (InetSocketAddress (Ipv4Address ("10.1.1.5"), port)));
app = onoff.Install (csmaNodes.Get (3));
app.Start (Seconds (1));
app.Stop (Seconds (10.0));
app = sink.Install (csmaNodes.Get (4));
app.Start (Seconds (0.0));
Ipv4GlobalRoutingHelper::PopulateRoutingTables ();
//抓取网络通信过程中的通信包
csma.EnablePcapAll ("CSAM_4pair_4Mbps_UDP", false);
FlowMonitorHelper flowmon;
flowmon.InstallAll ();
Simulator::Stop (Seconds (10));
Packet::EnablePrinting ();
//将网络仿真过程可视化,并且设置网络节点的位置。
AnimationInterface anim("CSAM_4pair_4Mbps_UDP.xml");
anim.SetConstantPosition(csmaNodes.Get(0),10,10);
anim.SetConstantPosition(csmaNodes.Get(1),10,20);
anim.SetConstantPosition(csmaNodes.Get(2),10,30);
anim.SetConstantPosition(csmaNodes.Get(3),20,10);
anim.SetConstantPosition(csmaNodes.Get(4),20,20);
anim.SetConstantPosition(csmaNodes.Get(5),20,30);
anim.SetConstantPosition(csmaNodes.Get(6),30,10);
anim.SetConstantPosition(csmaNodes.Get(7),30,20);
//仿真开始
Simulator::Run ();
//仿真流量监控
flowmon.SerializeToXmlFile ("CSAM_4pair_4Mbps_UDP.flowmon", true, true);
//仿真结束
Simulator::Destroy ();
return 0;
2.代码分析
2.1 其实在NS3中有很多可以实现UDP的类,但是为什么偏偏选择使用onoff类呢,主要有以下两个个原因:
- 可以控制流量,可以设置发送速率的大小,满足题目的要求。
- 便于UDP和TCP之间的转化,只需要修改 “ns3::UdpSocketFactory” 为**“ns3::TcpSocketFactory”** 就可以实现传输层协议的更换。
2.2 其次有基于 netanim 的仿真实现,其动态效果如下所示。
三、 总结
实验的全部代码可到我的资源中心下载
标签:include,Get,Seconds,app,入门教程,数据网络,ns3,csmaNodes 来源: https://blog.csdn.net/qq_42935317/article/details/113401173