/* -*- 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" //頭文件包含在build/ns3目錄下,頭文件裏包含的具體內容在ns-3.28/src中
#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; //創建命名空間,省去ns3::作用域操作符
NS_LOG_COMPONENT_DEFINE ("FirstScriptExample"); //用特殊的名字定義一個日誌組件
int
main (int argc, char *argv[])
{
CommandLine cmd;
cmd.Parse (argc, argv);
Time::SetResolution (Time::NS);
LogComponentEnable ("UdpEchoClientApplication", LOG_LEVEL_INFO); //設置客戶和服務器端的日誌級別爲“INFO”,當仿真產生數據的分組發送時,對應的應用就會輸出相應的日誌
LogComponentEnable ("UdpEchoServerApplication", LOG_LEVEL_INFO);
NodeContainer nodes; //定義網絡節點對象,在仿真中代表計算機
nodes.Create (2); //生成2個網絡節點
PointToPointHelper pointToPoint; //創建一個PointToPointHelper類的對象
pointToPoint.SetDeviceAttribute ("DataRate", StringValue ("5Mbps")); //創建一個PointToPointNetDevice對象時,設置傳輸速率爲5Mbit/s。
pointToPoint.SetChannelAttribute ("Delay", StringValue ("2ms")); //創建一個PointToPointChannel對象時,設置傳輸時延值爲2ms。
NetDeviceContainer devices; //聲明devices爲NetDeviceContainer類
devices = pointToPoint.Install (nodes); //爲每一個節點安裝點到點網絡設備,設備之間爲點到點信道,5Mbit/s以及2ms時延
InternetStackHelper stack; //爲計算機安裝網絡協議棧,主要爲IP層
stack.Install (nodes);
Ipv4AddressHelper address; //聲明節點設備IP地址
address.SetBase ("10.1.1.0", "255.255.255.0"); //設置IP地址與子網掩碼
Ipv4InterfaceContainer interfaces = address.Assign (devices); //將地址與網絡設備關聯起來,創建了一個接口列表
UdpEchoServerHelper echoServer (9); //聲明服務器端口號
ApplicationContainer serverApps = echoServer.Install (nodes.Get (1)); //在NodeContainer容器中索引爲1的節點上安裝一個UdpEchoServerApplication,返回一個容器,容器包含指向所有被助手創建的該節點的應用指針
serverApps.Start (Seconds (1.0)); //服務器應用在1s生效
serverApps.Stop (Seconds (10.0)); //服務器應用在10s失效
UdpEchoClientHelper echoClient (interfaces.GetAddress (1), 9); //聲明客戶端的遠端地址和遠端端口(可認爲時目標服務器地址和端口)
echoClient.SetAttribute ("MaxPackets", UintegerValue (1)); //告訴客戶端允許在模擬期間能發送的最大數據分組個數
echoClient.SetAttribute ("Interval", TimeValue (Seconds (1.0))); //告訴客戶端兩個數據分組之間要等待多長時間
echoClient.SetAttribute ("PacketSize", UintegerValue (1024)); //告訴客戶端數據分組應該承載多少數據
ApplicationContainer clientApps = echoClient.Install (nodes.Get (0)); //在NodeContainer容器中索引爲0的節點上安裝一個UdpEchoClientApplication,返回一個容器,容器包含指向所有被助手創建的該節點的應用指針
clientApps.Start (Seconds (2.0)); //客戶端應用在2s時生效
clientApps.Stop (Seconds (10.0)); //客戶端應用在10s時失效
Simulator::Run (); //啓動模擬器
Simulator::Destroy (); //銷燬模擬器
return 0;
}
NodeContainer類:爲ns-3中的一個Helper類,能一次操作多個節點。
Helper類:爲一簇類,幾乎所有的模塊都有一個或多個Helper類,負責把網絡設備連接到節點、信道,配置IP地址等任務。
PointToPointHelper類:負責設置網絡設備和信道屬性,並通過Install()方法把設備安裝到節點中。信道和網絡設備時對應的,比如以太網設備和無線信道就不能一起使用。
物理計算機連接:兩臺計算機成爲網絡一般來說需要使用網卡和網線。
ns-3中計算機物理連接:網卡抽象爲網絡設備,網線抽象爲信道。