Session 1. NS-3 개요( 환경 구축 및 transport layer model)

이옥환 , 신연철 Multimedia & Wireless Networking Laboratory, SNU

ohlee@mwnl.snu.ac.kr

ycshin@mwnl.snu.ac.kr

Contents Introduction to NS-3 Starting simulation Conceptual overview Tweaking Transport layer model Tracing system TCP Congestion Window tracing example

Introduction to NS-3

NS-3 NS-3 is targeted at networking research.

Discrete event simulator

Packet level simulator

Layered architecture

Wired and wireless network

NS-3 Status Periodic update

Latest version is ns-3.18

Supporting platform FreeBSD, Linux, SunOS, Solaris, Windows (Cygwin)

Free, open source software project

Website http://www.nsnam.org/ Can find the doxygen, reference manual, and tutorial

NS-3 vs. NS-2 Limitations of NS-2

Complicated architecture C++, Otcl

Simplified layers 2, 3, and applications Single network interface for each node

Advantages of NS-3 Simple architecture

C++ (Can run NS-3 without any knowledge of Python) Provides realistic implementations

NS-3 is not an extension of NS-2

NS-3 Components NS-3 simulator

Pre-processing Traffic / topology generation Alignment with real systems (sockets, device driver

interfaces)

Post-processing NS-3 output file (trace file) analysis

Throughput, delay, jitter, drop Various tracing system Graph

xgraph, gnuplot

NS-3 all-in-one package Directory Structure

ns-allinone-3.13

ns-3.13 nsc-0.5.2Pybindgen-0.15.0.795

bindings examplesdoc src

. . .

. . .

error-model

mobility

. . .

. . .

network

csma

. . .

scratch

Example simulation

scripts

Starting NS-3 Simulation

How to Download NS-3 Ns-3 download: http://www.nsnam.org/ns-3-15/download/

[user@com ~]# tar xvf ns-allinone-3.15.tar.bz2 [user@com ~]# cd ns-allinone-3.15

Ns-3 download using mercurial: [user@com ~]# hg clone http://code.nsnam.org/ns-3-allinone [user@com ~]# cd ns-3-allinone [user@com ~]# ./download.py -n ns-3.15

How to Install NS-3 Building

[user@com ~/ns-allinone-3.15]# ./build.py

Setting environment [user@com~/ns-allinone-3.15/ns-3.15]# ./waf –d optimized configure [user@com ~/ns-allinone-3.15/ns-3.15]# ./waf -d debug --enable-examples

--enable-tests configure [user@com ~/ns-allinone-3.15/ns-3.15]# ./waf [user@com ~/ns-allinone-3.15/ns-3.15]# ./test.py –c core

Simple Example cd ns-allinone-3.15/ns-3.15 /ns-3.15$ ./waf --run scratch/scratch-simulator

Output

Workspace

/ns-allinone-3.15/ns-3.15/scratch

Run program only in the scratch folder

Run program by the commands below ./waf --run scratch/example (or) ./waf --run example

NS-3 in Windows

Officially supported Virtualization products (VirtualBox, Vmware) How to run simulations using VirtualBox

http://www.nsnam.org/wiki/index.php/HOWTO_use_VirtualBox_to_run_simulations_on_Windows_machines

How to run simulations using VMware http://www.nsnam.org/wiki/index.php/HOWTO_use_VM

ware_to_set_up_virtual_networks_(Windows)

Cygwin was supported in the past There might be some problems

Conceptual Overview of NS-3

1. Key Abstractions2. Simulation Procedure3. Simulation Example

Key Abstractions1.Node Host, end system in the Internet Basic computing device abstraction Represented in C++ by the class Node

2.Application A user program that generates some activity to be simulated NS-3 applications run on ns-3 Nodes to drive simulations Represented in C++ by the class Application Ex)OnOffApplication, UdpEchoClientApplication

3.Channel Medium connected by nodes over which data flows Represented in C++ by the class Channel Ex) CsmaChannel, PointToPointChannel, WifiChannel

Key Abstractions

4. Net device Like a specific kind of network cable and a hardware device

(Network Interface Cards; NICs) NICs are controlled using the software driver, net devices Represented in C++ by the class NetDevice Provides methods for managing connection to Node and Channel Ex) CsmaNetDevice (work with CsmaChannel)

WifiNetDevice (work with WifiChannel)

5. Topology helpers Topology helpers make ns-3 core operations as easy as possible Create a NetDevice, add an address, install that net device on a

Node, configure the node’s protocol stack and connect the NetDevice to a Channel

Topology HelpersI. NodeContainer: Provide a convenient way to create, manage and

access any Node object

II. PointToPointHelper: Configure and connect PointToPointNetDevice and PointToPointChannel objects. Set DataRate on NetDevices and Delay on Channel

III. NetDeviceContainer: To install NetDevice at the nodes and create Channel between the nodes

IV. InternetStackHelper: To install an Internet Stack (TCP, UDP, IP, etc.) on each of the nodes in the node container

V. Ipv4AddressHelper: Manage the allocation of IP address and assign addresses to the devices using Ipv4InterfaceContainer

NS-3 Basic Simulation Model

Application Application

Protocol stack

Node

NetDevice NetDevice

Application Application

Protocol stack

Node

NetDevice NetDevice

Sockets-like API

Channel

Channel

Packet(s)

Simulation Procedure

1. Turning on logging

2. Creating network topology

3. Creating application

4. Running simulator

Simulation Procedure-1. Turning on logging -

Define log component NS_LOG_COMPONENT_DEFINE ( name )

Enable log component LogComponentEnable ( name, level )

Simulation Procedure- 2. Creating Network Topology -

Use Topology Helpers

NodeContainer NodeContainer Ptr<Node> NodeContainer::Create (n) n: # of Nodes Example)

NodeContainer nodes;nodes.Create (2);

Simulation Procedure- 2. Creating Network Topology -

PointToPointHelper void PointToPointHelper::SetDeviceAttribute (name, value) void PointToPointHelper::SetChannelAttribute (name, value) NetDeviceContainer PointToPointHelper::Install (NodeContainer c)

NetDeviceContainer NetDeviceContainer Ptr<NetDevice>

ExamplePointToPointHelper pointToPoint;pointToPoint.SetDeviceAttribute ("DataRate", StringValue ("5Mbps"));pointToPoint.SetChannelAttribute ("Delay", StringValue ("2ms"));NetDeviceContainer devices;devices = pointToPoint.Install (nodes);

Simulation Procedure- 3. Creating application -

UdpEchoServerHelper UdpEchoServerHelper::UdpEchoServerHelper ( port ) ApplicationContainer UdpEchoServerHelper::Install (NodeContainer c )

UdpEchoClientHelper UdpEchoClientHelper::UdpEchoClientHelper ( ip, port ) void UdpEchoClientHelper::Setattribute ( name, value ) ApplicationContainer UdpEchoClientHelper::Install (NodeContainer c )

ExampleUdpEchoServerHelper echoServer (9);

ApplicationContainer serverApps = echoServer.Install (nodes.Get (1));serverApps.Start (Seconds (1.0));serverApps.Stop (Seconds (10.0));

UdpEchoClientHelper echoClient (interfaces.GetAddress (1), 9);echoClient.SetAttribute ("MaxPackets", UintegerValue (1));echoClient.SetAttribute ("Interval", TimeValue (Seconds (1.0)));echoClient.SetAttribute ("PacketSize", UintegerValue (1024));ApplicationContainer clientApps = echoClient.Install (nodes.Get (0));clientApps.Start (Seconds (2.0));clientApps.Stop (Seconds (10.0));

Simulation Procedure- 4. Running simulator-

Start Simulator Simulator::Run ();

Destroy Simulator Simulator::Destroy ();

Simulation Example

UDP EchoClient10.1.1.1

UDP EchoServer

10.1.1.2P2P interface P2P interface

Transmit a packet at 1s

Upon receiving the packet, echo it

Data rate: 5Mbps, Delay: 2ms

Simulation Example (1/3)

#include "ns3/core-module.h" #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; NS_LOG_COMPONENT_DEFINE ("FirstScriptExample"); int main (int argc, char *argv[])

{ LogComponentEnable("UdpEchoClientApplication", LOG_LEVEL_INFO); LogComponentEnable("UdpEchoServerApplication", LOG_LEVEL_INFO); NodeContainer nodes; nodes.Create (2); PointToPointHelper pointToPoint; pointToPoint.SetDeviceAttribute ("DataRate", StringValue ("5Mbps")); pointToPoint.SetChannelAttribute ("Delay", StringValue ("2ms")); NetDeviceContainer devices; devices = pointToPoint.Install (nodes);

• Simple point-to-point link between two nodes and echo a single packet

Simulation Example (2/3) InternetStackHelper stack; stack.Install (nodes); Ipv4AddressHelper address; address.SetBase ("10.1.1.0", "255.255.255.0"); Ipv4InterfaceContainer interfaces = address.Assign (devices); UdpEchoServerHelper echoServer (9); ApplicationContainer serverApps = echoServer.Install (nodes.Get (1)); serverApps.Start (Seconds (1.0)); serverApps.Stop (Seconds (10.0)); UdpEchoClientHelper echoClient (interfaces.GetAddress (1), 9); echoClient.SetAttribute ("MaxPackets", UintegerValue (1)); echoClient.SetAttribute ("Interval", TimeValue (Seconds (1.0))); echoClient.SetAttribute ("PacketSize", UintegerValue (1024)); ApplicationContainer clientApps = echoClient.Install (nodes.Get (0)); clientApps.Start (Seconds (2.0)); clientApps.Stop (Seconds (10.0)); Simulator::Run (); Simulator::Destroy (); return 0; }

Simulation Example (3/3)

../ns-3.15] ./waf –-run scratch/example1

OutputSent 1024 bytes to 10.1.1.2Received 1024 bytes from 10.1.1.1Received 1024 bytes from 10.1.1.2

Tweaking1. Logging Modules2. Command Line Arguments3. Tracing System

Logging Module Output messages from modules Useful when debugging NS_LOG environment variable NS_LOG_FUNCTION level information Verbosity level

NS LOG ERROR — Log error messages; NS LOG WARN — Log warning messages; NS LOG DEBUG — Log relatively rare debugging messages; NS LOG INFO — Log informational messages about program progress; NS LOG FUNCTION — Log a message describing each function called; NS LOG LOGIC – Log messages describing logical flow within a function; NS LOG ALL — Log everything. NS LOG UNCOND – Log the associated message unconditionally.

Logging Module Example 1

$ export NS_LOG=UdpEchoClientApplication=level_all $ ./waf --run scratch/example1

Output:’build’ finished successfully (0.404s)UdpEchoClientApplication:UdpEchoClient()UdpEchoClientApplication:SetDataSize(1024)UdpEchoClientApplication:StartApplication()UdpEchoClientApplication:ScheduleTransmit()UdpEchoClientApplication:Send()Sent 1024 bytes to 10.1.1.2Received 1024 bytes from 10.1.1.1UdpEchoClientApplication:HandleRead(0x6241e0, 0x624a20)Received 1024 bytes from 10.1.1.2UdpEchoClientApplication:StopApplication()UdpEchoClientApplication:DoDispose()UdpEchoClientApplication:~UdpEchoClient()

Logging Module Example 2

$ export ‘NS_LOG=UdpEchoClientApplication=level_all|prefix_func|prefix_time’ $ ./waf --run scratch/example1

Output:

0s UdpEchoClientApplication:UdpEchoClient()0s UdpEchoClientApplication:SetDataSize(1024)2s UdpEchoClientApplication:StartApplication()2s UdpEchoClientApplication:ScheduleTransmit()2s UdpEchoClientApplication:Send()2s UdpEchoClientApplication:Send(): Sent 1024 bytes to 10.1.1.2Received 1024 bytes from 10.1.1.12.00737s UdpEchoClientApplication:HandleRead(0x9aead30, 0x9aeb378)2.00737s UdpEchoClientApplication:HandleRead(): Received 1024 bytes from 10.1.1.210s UdpEchoClientApplication:StopApplication()UdpEchoClientApplication:DoDispose()UdpEchoClientApplication:~UdpEchoClient()

Logging Module Example 3

$ export ‘NS_LOG=*=level_all|prefix_func|prefix_time’ $ ./waf --run scratch/example1

It prints out all of the logging ./waf –-run scratch/example1 > log.out 2>&1 2>&1 : stderr > stdout

Example 4 Adding logging to your code

NS_LOG_INFO (“Creating Topology”) in your source code $ export NS_LOG=FirstScriptExample=info ./waf --run scratch/example1

Command Line Arguments Change the simulation parameters using command line

arguments

First declare the command line parser in main functionCommandLine cmd;cmd.Parse (argc, argv);

Example ./waf --run "scratch/example1 –PrintHelp” ./waf –-run “scratch/example1 –

PrintAttributes=ns3::PointToPointNetDevice” ./waf --run “scratch/example1 -

ns3::PointToPointNetDevice::DataRate=5Mbps –ns3::PointToPointChannel::Delay=2ms”

Command Line Arguments When add your own hooks.

cmd.AddValue in main function

Exampleint main (int argc, char *argv[]){

uint32_t nPackets =1;

CommandLine cmd;cmd.AddValue("nPackets", "Number of packets to echo", nPackets);Cmd.Parse (argc, argv);

…echoClient.SetAttribute (“MaxPackets”, UintegerValue (nPackets));

./waf --run “scratch/example1 –nPackets=2”

Tracing System

Tracing is a structured form of simulation output

Tracing System ASCII Tracing

Trace file similar to that of NS-2

AsciiTraceHelper ascii;pointToPoint.EnableAsciiAll (ascii.CreateFileStream(“myfirst.tr”));

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

Output (myfirst.tr)+ 2 /NodeList/0/DeviceList/0/$ns3::PointToPointNetDevice/TxQueue/Enqueue ns3::PppHeader (Point-to-Point Protocol: IP (0x0021)) ns3::Ipv4Header (tos 0x0 ttl 64 id 0 protocol 17 offset 0 flags [none] length: 1052 10.1.1.1 > 10.1.1.2) ns3::UdpHeader (length: 1032 49153 > 9) Payload (size=1024)- 2 /NodeList/0/DeviceList/0/$ns3::PointToPointNetDevice/TxQueue/Dequeue ns3::PppHeader (Point-to-Point Protocol: IP (0x0021)) ns3::Ipv4Header (tos 0x0 ttl 64 id 0 protocol 17 offset 0 flags [none] length: 1052 10.1.1.1 > 10.1.1.2) ns3::UdpHeader (length: 1032 49153 > 9) Payload (size=1024)

…

Tracing System Trace file format

00 +01 202 /NodeList/0/DeviceList/0/$ns3::PointToPointNetDevice/TxQueue/Enqueue03 ns3::PppHeader (04 Point-to-Point Protocol: IP (0x0021))05 ns3::Ipv4Header (06 tos 0x0 ttl 64 id 0 protocol 17 offset 0 flags [none]07 length: 1052 10.1.1.1 > 10.1.1.2)08 ns3::UdpHeader (09 length: 1032 49153 > 9)10 Payload (size=1024)

Tracing System PCAP Tracing

.pcap file format Traffic trace analyze pointToPoint.EnablePcapAll (“myfirst”);

Reading output with tcpdump$ tcpdump -nn -tt -r myfirst-0-0.pcapreading from file myfirst-0-0.pcap, link-type PPP (PPP)2.000000 IP 10.1.1.1.49153 > 10.1.1.2.9: UDP, length 10242.514648 IP 10.1.1.2.9 > 10.1.1.1.49153: UDP, length 1024

$ tcpdump -nn -tt -r myfirst-1-0.pcapreading from file myfirst-1-0.pcap, link-type PPP (PPP)2.257324 IP 10.1.1.1.49153 > 10.1.1.2.9: UDP, length 10242.257324 IP 10.1.1.2.9 > 10.1.1.1.49153: UDP, length 1024

Tracing System Reading output with Wireshark http://www.wireshark.org/download.html

Summary of Tweaking 1. Logging Module

Used to output debug messages based on the pre-defined log component

2. Command Line Argument Change parameters without direct modification of main source

code

3. Tracing System Used to generate output for checking the operation and measure

the system performance Use trace source and trace sink (we study the tracing system

further in the 2nd class)

Transport Layer Model in NS-3

TCP Models in NS-3 NS-3 was written to support multiple TCP implementations

Two important abstract base classes Class TcpSocket

Defined in src/node/tcp-socket.{cc,h} Class TcpSocketFactory

Used by applications to create TCP sockets

Limitations Only Tahoe congestion control Limited IPv6 support

TcpSocket Class Attributes

SndBufSize: TcpSocket maximum transmit buffer size (bytes) Set with class: ns3::UintegerValue Underlying type: uint32_t  / Initial value: 131072

RcvBufSize: TcpSocket maximum receive buffer size (bytes) Set with class: ns3::UintegerValue Underlying type: uint32_t  / Initial value: 131072

SegmentSize: TCP maximum segment size in bytes (may be adjusted based on MTU discovery)

Set with class: ns3::UintegerValue Underlying type: uint32_t  / Initial value: 536

SlowStartThreshold: TCP slow start threshold (bytes) Set with class: ns3::UintegerValue Underlying type: uint32_t  / Initial value: 65535

InitialCwnd: TCP initial congestion window size (segments) Set with class: ns3::UintegerValue Underlying type: uint32_t  / Initial value: 1

ConnTimeout: TCP retransmission timeout when opening connection (seconds)

Set with class: TimeValue Underlying type: Time / Initial value: +3000000000.0ns

ConnCount: Number of connection attempts (SYN retransmissions) before returning failure

Set with class: ns3::UintegerValue Underlying type: uint32_t  / Initial value: 6

DelAckTimeout: Timeout value for TCP delayed acks, in seconds Set with class: TimeValue Underlying type: Time / Initial value: +200000000.0ns

DelAckCount: Number of packets to wait before sending a TCP ack Set with class: ns3::UintegerValue Underlying type: uint32_t  / Initial value: 2

PersistTimeout: Persist timeout to probe for rx window Set with class: TimeValue Underlying type: Time / Initial value: +6000000000.0ns

TcpSocket Class Attributes

UDP Models in NS-3 Two important abstract base classes

Class UdpSocket Defined in src/node/udp-socket.{cc,h}

Class UdpSocketFactory Used by applications to create UDP sockets.

* Attributes RcvBufSize: UdpSocket maximum receive buffer size (bytes)

Set with class: ns3::UintegerValue Underlying type: uint32_t  / Initial value: 131072

IpTtl: socket-specific TTL for unicast IP packets (if non-zero) Set with class: ns3::UintegerValue Underlying type: uint8_t / Initial value: 0

IpMulticastTtl: socket-specific TTL for multicast IP packets (if non-zero) Set with class: ns3::UintegerValue Underlying type: uint8_t / Initial value: 0

IpMulticastIf: interface index for outgoing multicast on this socket; -1 indicates to use default interface Set with class: ns3::IntegerValue Underlying type: int32_t  / Initial value: -1

IpMulticastLoop: whether outgoing multicast sent also to loopback interface Set with class: BooleanValue Underlying type: bool / Initial value: false

MtuDiscover: If enabled, every outgoing ip packet will have the DF flag set. Set with class: BooleanValue Underlying type: bool / Initial value: false

SocketFactory Class Object to create transport layer instances that provide a socket API to applications

Public Member Functions virtual Ptr< Socket > CreateSocket (void)=0

Static Public Member Functions static TypeId GetTypeId (void)

This method returns the TypeId associated to ns3::SocketFactory

Tracing System

1. Tracing overview2. Callback3. How to Find and Connect The Trace Source4. Mid, high-level tracing

Tracing Overview Concept: Independent tracing sources and tracing sinks along with a

uniform mechanism for connecting sources to sinks

Trace sources Entities that can signal events and provide access to interesting data (indicate when a

packet is received or when an interesting state change happens) Generator of events

Trace sinks: Entities that consume trace information

Simulator provides a set of pre-configured trace sources

Trace source is a kind of point-to-multipoint information link One trace source can be connected by several trace sinks

Callback and Low-Level Tracing Callback

The object is to allow a piece of code to call a function without any specific inter-module dependency

Treat the address of the called function as a variable, i.e. a pointer-to-function variable

Decouple the calling function from the called class completely

Relation between tracing system and callback A trace source is a callback When a trace sink wants to know information given by a trace source, it

adds its own function to the callback list.

For the further study of the callbacks, it is good to refer callback part in ns-3 manual pp.12-14.

Simple Low-level Tracing Example (1/2)#include "ns3/object.h"#include "ns3/uinteger.h"#include "ns3/traced-value.h"#include "ns3/trace-source-accessor.h"#include <iostream>

using namespace ns3;class MyObject : public Object{public: static TypeId GetTypeId (void) { static TypeId tid = TypeId ("MyObject") .SetParent (Object::GetTypeId ()) .AddConstructor<MyObject> () .AddTraceSource ("MyInteger",

"An integer value to trace.", MakeTraceSourceAccessor (&MyObject::m_myInt)) ; return tid; } MyObject () {} TracedValue<int32_t> m_myInt;};

Provides the “hooks” used for connecting the trace source to the outside the config system

Provides the infrastructure that overloads the operators and drives callback process

Simple Low-level Tracing Example (2/2)

voidIntTrace (int32_t oldValue, int32_t newValue){std::cout << "Traced " << oldValue << " to " << newValue << std::endl;}

intmain (int argc, char *argv[]){ Ptr<MyObject> myObject = CreateObject<MyObject> (); myObject->TraceConnectWithoutContext ("MyInteger", MakeCallback(&IntTrace)); myObject->m_myInt = 1234;}

Trace sink; callback function: this function will be called whenever the overloaded operators of the TracedValue is excuted

Connect between trace source and trace sink

Operator”=” invoke the Callback

TypeId in Simple Low-level Tracing Example

.AddTraceSource ("MyInteger", "An integer value to trace.",

MakeTraceSourceAccessor (&MyObject::m_myInt))

Config Subsystem Tracing

Config path (the context) Path of predefined trace source Represents a chain of Object pointers Ex) /NodeList/7/$ns3::MobilityModel/CourseChange

Config subsystem is used to allow selecting a trace source in the config path

void ns3::Config::Connect(std::string path,const CallbackBase & cb )

Config Subsystem Tracing ExamplevoidCourseChange (std::string context, Ptr<const MobilityModel> model){ Vector position = model->GetPosition (); NS_LOG_UNCOND (context << " x = " << position.x << ", y = " << position.y);}

//Trace Sink

std::ostringstream oss;oss << "/NodeList/" << wifiStaNodes.Get (nWifi - 1)->GetId () << "/$ns3::MobilityModel/CourseChange";

//Config Path

Config::Connect (oss.str (), MakeCallback (&CourseChange));

//Connection between Trace Source and Sink

Output Result:/NodeList/7/$ns3::MobilityModel/CourseChange x = 7.27897, y = 2.22677…

How to Find and Connect The Trace Source

I. How to find out what trace sources are available.

II. How to figure out the config path to use to connect to the trace source.

III. How to figure out what the return type and formal arguments of the callback function

1. What Trace Sources are Available?

NS-3 Doxygen (http://www.nsnam.org/doxygen-release/index.html)

2. Figure out the Config Path to use to connect to the trace source

Find existing implementation within example codes

Using find & grep command We want to find the examples which contain “CourseChange” and

“Connect”

find . –name ‘*.cc’ | xargs grep CourseChange | grep Connect

3. What are the return type and formal arguments of the callback function?

The return value of callback: void

The return value of callback: void

Config::ConnectWithoutContext void ns3::Config::ConnectWithoutContext (std::string path, const CallbackBase & cb)

path a path to match trace sources cb the callback to connect to the matching trace sources

To find all trace sources which match the input path and will connect the input callback to them

Config::Connect void ns3::Config::Connect (std::string path, const CallbackBase & cb)

path a path to match trace sources cb the callback to connect to the matching trace sources

To find all trace sources which match the input path and will connect the input callback to them in such a way that the callback will receive an extra context string upon trace event notification

3. What are the return type and formal arguments of the callback function?

What about TracedValue? TracedValue is templated src/core/model/traced-value.h

The set code will fire the m_cb callback with two parameters

The callback, m_cb is declared as a TraceCallback<T, T>

3. What are the return type and formal arguments of the callback function?

To customized how information is extracted and saved

To control the amount output, save data to a file and refer back to it later

Use the mid-level trace helpers to do that

Using Mid-level Helpers

High-level of tracing

Control the collection of pre-defined outputs to a fine granularity

All helpers provide ascii and pcap trace sinks Ascii Tracing Device Helpers Pcap Tracing Device Helpers

src/network/helper/trace-helper.h

TCP Congestion Window Tracing Example

Topology

CongestionWindow Trace Source Which class contains CongestionWindow as a trace source?

CongestionWindow Trace Source src/internet/model/tcp-tahoe.cc src/internet/model/tcp-tahoe.h

What Script to Use? Find the proper example

find . –name ‘*.cc’ | xargs grep CongestionWindow

Find the proper example find . –name ‘*.cc’ | xargs grep m_cWnd

Example Code (1/3)#include <fstream>#include "ns3/core-module.h“#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;

NS_LOG_COMPONENT_DEFINE ("FifthScriptExample");

class MyApp : public Application {public:

MyApp (); virtual ~MyApp();

void Setup (Ptr<Socket> socket, Address address, uint32_t packetSize, uint32_t nPackets, DataRate dataRate);

private: virtual void StartApplication (void); virtual void StopApplication (void);

void ScheduleTx (void); void SendPacket (void);

Ptr<Socket> m_socket; Address m_peer; uint32_t m_packetSize; uint32_t m_nPackets; DataRate m_dataRate; EventId m_sendEvent; bool m_running; uint32_t m_packetsSent;};

MyApp::MyApp () : m_socket (0), m_peer (), m_packetSize (0), m_nPackets (0), m_dataRate (0), m_sendEvent (), m_running (false), m_packetsSent (0){}

MyApp::~MyApp(){ m_socket = 0;}

voidMyApp::Setup (Ptr<Socket> socket, Address address, uint32_t packetSize, uint32_t nPackets, DataRate dataRate){ m_socket = socket; m_peer = address; m_packetSize = packetSize; m_nPackets = nPackets; m_dataRate = dataRate;}

voidMyApp::StartApplication (void){ m_running = true; m_packetsSent = 0; m_socket->Bind (); m_socket->Connect (m_peer); SendPacket ();}

Create a simple application

ns-allinone-3.12.1/ns-3.12.1/examples/tutorial/fifth.cc

Example Code (2/3)void MyApp::StopApplication (void){ m_running = false;

if (m_sendEvent.IsRunning ()) { Simulator::Cancel (m_sendEvent); }

if (m_socket) { m_socket->Close (); }}

void MyApp::SendPacket (void){ Ptr<Packet> packet = Create<Packet> (m_packetSize); m_socket->Send (packet);

if (++m_packetsSent < m_nPackets) { ScheduleTx (); }}

void MyApp::ScheduleTx (void){ if (m_running) { Time tNext (Seconds (m_packetSize * 8 /

static_cast<double> (m_dataRate.GetBitRate ()))); m_sendEvent = Simulator::Schedule (tNext,

&MyApp::SendPacket, this); }}

static voidCwndChange (uint32_t oldCwnd, uint32_t newCwnd){ NS_LOG_UNCOND (Simulator::Now ().GetSeconds () << "\t" << newCwnd);}

static voidRxDrop (Ptr<const Packet> p){ NS_LOG_UNCOND ("RxDrop at " << Simulator::Now ().GetSeconds ());}

int main (int argc, char *argv[]){ NodeContainer nodes; nodes.Create (2);

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

NetDeviceContainer devices; devices = pointToPoint.Install (nodes);

Ptr<RateErrorModel> em = CreateObjectWithAttributes<RateErrorModel> ( "RanVar", RandomVariableValue (UniformVariable (0., 1.)), "ErrorRate", DoubleValue (0.00001)); devices.Get (1)->SetAttribute ("ReceiveErrorModel", PointerValue (em));

InternetStackHelper stack; stack.Install (nodes);

Ipv4AddressHelper address; address.SetBase ("10.1.1.0", "255.255.255.252"); Ipv4InterfaceContainer interfaces = address.Assign (devices);

Trace sink

Create network topology and error model

Example Code (3/3) uint16_t sinkPort = 8080; Address sinkAddress

(InetSocketAddress(interfaces.GetAddress (1), sinkPort));

PacketSinkHelper packetSinkHelper ("ns3::TcpSocketFactory", InetSocketAddress (Ipv4Address::GetAny (), sinkPort));

ApplicationContainer sinkApps = packetSinkHelper.Install (nodes.Get (1));

sinkApps.Start (Seconds (0.)); sinkApps.Stop (Seconds (20.));

Ptr<Socket> ns3TcpSocket =Socket::CreateSocket (nodes.Get (0),

TcpSocketFactory::GetTypeId ()); ns3TcpSocket->TraceConnectWithoutContext

("CongestionWindow", MakeCallback (&CwndChange));

Ptr<MyApp> app = CreateObject<MyApp> (); app->Setup (ns3TcpSocket, sinkAddress, 1040, 1000,

DataRate ("1Mbps")); nodes.Get (0)->AddApplication (app); app->SetStartTime (Seconds (1.)); app->SetStopTime (Seconds (20.));

devices.Get (1)->TraceConnectWithoutContext("PhyRxDrop", MakeCallback (&RxDrop));

Simulator::Stop (Seconds(20)); Simulator::Run (); Simulator::Destroy ();

return 0;}

TCP sink application

TCP application

Connect Cwnd trace source and sink

Connect RxDrop trace source and sink

Example Code

Callback Function

Static voidCwndChange (uint32_t oldCwnd, uint32_t newCwnd){

NS_LOG_UNCOND (Simulator::Now ().GetSeconds () << “\t” << newCwnd);}

Static voidRxDrop (Ptr<const Packet> p){

NS_LOG_UNCON (“RxDrop at” << Simulator::Now ().GetSeconds ();}

Connect a trace source and trace sink

ns3TcpSocket->TraceConnectWithoutContext (“CongestionWindow”, MakeCallback (&CwndChange));

devices.Get(1)->TraceConnectWithoutContext (“PhyRxDrop”, MakeCallback (&RxDrop));

Output Result In ns-allinone-3.12.1/ns-3.12.1/examples/tutorial

tutorial$ cp fifth.cc ~/ns-allinone-3.12.1/ns-3.12.1/scratch/filename.cc ns-3.12.1$ ./waf --run filename

Output Result

Using Mid-level helperstatic voidCwndChange (Ptr<OutputStreamWrapper> stream, uint32_t oldCwnd, uint32_t newCwnd){NS_LOG_UNCOND (Simulator::Now ().GetSeconds () << "\t" << newCwnd);*stream->GetStream () << Simulator::Now ().GetSeconds () << "\t" << oldCwnd << "\t" <<

newCwnd << std::endl; }

static voidRxDrop (Ptr<PcapFileWrapper> file, Ptr<const Packet> p){NS_LOG_UNCOND ("RxDrop at " << Simulator::Now ().GetSeconds ());file->Write(Simulator::Now(), p);}…AsciiTraceHelper asciiTraceHelper;Ptr<OutputStreamWrapper> stream = asciiTraceHelper.CreateFileStream ("sixth.cwnd");ns3TcpSocket->TraceConnectWithoutContext ("CongestionWindow", MakeBoundCallback

(&CwndChange, stream));

PcapHelper pcapHelper;Ptr<PcapFileWrapper> file = pcapHelper.CreateFile ("sixth.pcap", std::ios::out,

PcapHelper::devices.Get (1)->TraceConnectWithoutContext("PhyRxDrop", MakeBoundCallback (&RxDrop, file));

References Network Simulator

http://www.nsnam.org

NS-3 tutorial http://www.nsnam.org/docs/release/3.12/tutorial/singleht

ml/index.html

NS-3 manual http://www.nsnam.org/docs/release/3.12/manual/singleht

ml/index.html