ns3中的openflow-switch例子

NS3安装完之后可以再src文件夹下找到openflow的例子，openflow的模块安装完之后，运行example里面的例子openflow-switch.cc.但是这个例子中的拓扑只有一个交换机，连接着四个节点，现在想要修改一下这个拓扑，改成下面的这种拓扑结构：

修改之后的相应代码如下：

</pre><pre name="code" class="html">#include <iostream>#include <fstream>#include "ns3/core-module.h"#include "ns3/network-module.h"#include "ns3/csma-module.h"#include "ns3/internet-module.h"#include "ns3/applications-module.h"#include "ns3/openflow-module.h"#include "ns3/log.h"#include "ns3/bridge-helper.h"using namespace ns3;NS_LOG_COMPONENT_DEFINE("OpenFlowCsmaSwitch");bool verbose = false;bool use_drop = false;ns3::Time timeout = ns3::Seconds (0);boolSetVerbose (std::string value){  verbose = true;    return true;}boolSetDrop (std::string value){  use_drop = true;    return true;}boolSetTimeout (std::string value){  try {        timeout = ns3::Seconds (atof (value.c_str ()));      return true;      }    catch (...) { return false; }  return false;}intmain(int argc,char *argv[]){CommandLine cmd;cmd.AddValue ("v", "Verbose (turns on logging).", MakeCallback (&SetVerbose));cmd.AddValue ("verbose", "Verbose (turns on logging).", MakeCallback (&SetVerbose));cmd.AddValue ("d", "Use Drop Controller (Learning if not specified).", MakeCallback (&SetDrop));cmd.AddValue ("drop", "Use Drop Controller (Learning if not specified).", MakeCallback (&SetDrop));cmd.AddValue ("t", "Learning Controller Timeout (has no effect if drop controller is specified).", MakeCallback ( &SetTimeout));cmd.AddValue ("timeout", "Learning Controller Timeout (has no effect if drop controller is specified).", MakeCallback ( &SetTimeout));cmd.Parse (argc, argv);if (verbose){LogComponentEnable ("OpenFlowCsmaSwitch", LOG_LEVEL_INFO);LogComponentEnable ("OpenFlowInterface", LOG_LEVEL_INFO);LogComponentEnable ("OpenFlowSwitchNetDevice", LOG_LEVEL_INFO);LogComponentEnable ("UdpEchoClientApplication", LOG_LEVEL_INFO);LogComponentEnable ("UdpEchoServerApplication", LOG_LEVEL_INFO);}NS_LOG_INFO ("Create nodes");NodeContainer terminals;terminals.Create(4);NodeContainer ofSwitch;ofSwitch.Create(2);NS_LOG_INFO ("Create Topology");CsmaHelper csma;csma.SetChannelAttribute("DataRate",DataRateValue(5000000));csma.SetChannelAttribute("Delay",TimeValue(MilliSeconds(2)));NetDeviceContainer terminalDevices;NetDeviceContainer switchDevice1,switchDevice2;NetDeviceContainer link;//Connect ofSwitch1 to ofSwitch2link = csma.Install(NodeContainer(ofSwitch.Get(0),ofSwitch.Get(1)));switchDevice1.Add(link.Get(0));switchDevice2.Add(link.Get(1));//Connect terminal1 and terminal2 to ofSwitch1for (int i = 0;i < 2;i ++){link = csma.Install(NodeContainer(terminals.Get(i),ofSwitch.Get(0)));terminalDevices.Add(link.Get(0));switchDevice1.Add(link.Get(1));}//Connect terminal3 and terminal4 to ofSwitch2for (int i = 2;i < 4;i ++){link = csma.Install(NodeContainer(terminals.Get(i),ofSwitch.Get(1)));terminalDevices.Add(link.Get(0));switchDevice2.Add(link.Get(1));}//Create the switch netdevice,which will do the packet switchingPtr<Node> OFNode1 = ofSwitch.Get(0);Ptr<Node> OFNode2 = ofSwitch.Get(1);OpenFlowSwitchHelper ofswHelper;if (use_drop){Ptr<ns3::ofi::DropController> controller1 = CreateObject<ns3::ofi::DropController> ();ofswHelper.Install (OFNode1, switchDevice1, controller1);Ptr<ns3::ofi::DropController> controller2 = CreateObject<ns3::ofi::DropController> ();ofswHelper.Install (OFNode2, switchDevice2, controller2);}else{Ptr<ns3::ofi::LearningController> controller1 = CreateObject<ns3::ofi::LearningController> ();if (!timeout.IsZero ()) controller1->SetAttribute ("ExpirationTime", TimeValue (timeout));ofswHelper.Install (OFNode1, switchDevice1, controller1);Ptr<ns3::ofi::LearningController> controller2 = CreateObject<ns3::ofi::LearningController> ();if (!timeout.IsZero ()) controller2->SetAttribute ("ExpirationTime", TimeValue (timeout));ofswHelper.Install (OFNode2, switchDevice2, controller2);}//Add internet stacks to the terminalsInternetStackHelper internet;internet.Install (terminals);//Add IP addressesNS_LOG_INFO ("Assign IP Addresses.");Ipv4AddressHelper ipv4;ipv4.SetBase ("10.1.1.0", "255.255.255.0");Ipv4InterfaceContainer interface = ipv4.Assign(terminalDevices);//Add applicationsNS_LOG_INFO ("Create an application");UdpEchoServerHelper echoServer (9);ApplicationContainer serverApps = echoServer.Install (terminals.Get(0));serverApps.Start (Seconds(1.0));serverApps.Stop (Seconds(10.0));UdpEchoClientHelper echoClient (Ipv4Address("10.1.1.1"),9);echoClient.SetAttribute ("MaxPackets", UintegerValue (5));echoClient.SetAttribute ("Interval", TimeValue (Seconds (1.0)));echoClient.SetAttribute ("PacketSize", UintegerValue (1024));ApplicationContainer clientApps = echoClient.Install(terminals.Get(3));clientApps.Start (Seconds(2.0));clientApps.Stop (Seconds(10.0));AsciiTraceHelper ascii;csma.EnableAsciiAll (ascii.CreateFileStream ("openflow-switch.tr"));csma.EnablePcapAll ("openflow-switch", false);NS_LOG_INFO ("Run simulation");Simulator::Run();Simulator::Destroy();NS_LOG_INFO ("Done.");//#else//NS_LOG_INFO ("NS-3 OpenFlow is not enabled. Cannot run simulation.");//#endif // NS3_OPENFLOW}

节点之间可以在LearningController下的控制下通信，可以查看pcap文件来查看相应的通信过程中的信息。