ns-3 Training
Computer and Communication Network Lab
Department of Electrical Engineering
National Sun Yat-Sen University
5/13/2013
Topics
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Getting Started ns-3
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A First ns-3 Script
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What is ns-3?
Installation
Two tutorial examples
A simple example for this project
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Complete the remaining parts
2
Getting Started ns-3
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Please read the following documents
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ns-3 overview
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ns-3 Tutorial
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http://www.nsnam.org/docs/ns-3-overview.ppt
http://www.nsnam.org/docs/ns-3-overview.pdf
http://www.nsnam.org/docs/release/3.13/tutorial/ns-3-tutorial.pdf
ns-3 Manual
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http://www.nsnam.org/docs/release/3.13/manual/ns-3-manual.pdf
What is ns-3?

ns-3 is a discrete-event network simulator for
Internet systems
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ns-3 allows researchers to study Internet protocols
and large-scale systems in a controlled environment
ns-3 is a new simulator (not backwards-compatible
with ns-2)
ns-3 is a free, open source software project
organized around research community
development and maintenance

the target user community is networking researchers
and educators
4
Extensible Software Core

Written in C++ with optional Python interface
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extensively documented API (doxygen):
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http://www.nsnam.org/doxygen-release/index.html
5
Node Basics
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An ns-3 Node is a husk of a computer to which
applications, stacks, and NICs are added
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Tracing and Statistics
Tracing is a structured form of simulation output
 Example (from ns-2):
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Problem: Tracing needs vary widely
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would like to change tracing output without editing the
core
would like to support multiple outputs
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ns-3 Has A New Tracing Model
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ns-3 solution: decouple trace sources from trace
sinks
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Benefit: Customizable trace sinks
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Downloading ns-3

http://www.nsnam.org/

Latest release: ns-3.16 (2012/12/21)
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Problems under Windows

Cygwin or MinGW

If you do use Cygwin or MinGW and use Logitech
products


it can cause Cygwin or MinGW DLLs to die in mysterious
way
Note that NSC is not supported on OSX or Cygwin.
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Network Simulation Cradle
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Building ns-3 (1/5)
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# ./build.py
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Building ns-3 (2/5)
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# ./waf -d optimized configure
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ns-3 uses the waf build system
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Building ns-3 (3/5)
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# ./waf -d debug configure
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Building ns-3 (4/5)
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# ./test.py -c core
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Building ns-3 (5/5)
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Running a Script
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./waf --run hello-simulator
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Building Your Script
# cp examples/tutorial/first.cc scratch/myfirst.cc
 ./waf
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Building Your Script
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# ./waf --run scratch/myfirst
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A First ns-3 Script
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/ns-allinone-3.10/ns-3.10/examples/tutorial
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first.cc
third.cc
Boilerplate

The first line in the file is an emacs mode line.
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
The ns-3 simulator is licensed using the GNU
General Public License.
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Module Includes
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The code proper starts with a number of include
statements.
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../../build/debug/ns3
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Ns3 Namespace
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The next line in the first.cc script is a namespace
declaration.
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Logging
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Main Functions
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The next lines of the script you will find are,
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ns3 提供的 log 訊息分成了以下幾個等級：
1.NS_LOG_ERROR — Log error messages;
2.NS_LOG_WARN — Log warning messages;
3.NS_LOG_DEBUG — Log relatively rare, ad-hoc debugging messages;
4.NS_LOG_INFO — Log informational messages about program progress;
5.NS_LOG_FUNCTION — Log a message describing each function called;
6.NS_LOG_LOGIC – Log messages describing logical flow within a function;
7.NS_LOG_ALL — Log everything.
8.NS_LOG_UNCOND – Log the associated message unconditionally.
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Topology Helpers

Create the ns-3 Node objects that will represent
the computers in the simulation.
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We are constructing a point to point link
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Topology Helpers
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We will need to have a list of all of the NetDevice
objects that are created
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Internet Stack Helper
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Protocol stacks installed on our nodes
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TCP, UDP, IP, etc.
Ipv4AddressHelper
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make the association between an IP address and a device
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Applications
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Two specializations of the core ns-3 class
Application called
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UdpEchoServerApplication
UdpEchoClientApplication
UdpEchoServerHelper
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Applications
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UdpEchoClientHelper
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Simulator
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What we need to do at this point is to actually
run the simulation.
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scheduled events in the simulator at 1.0 seconds, 2.0
seconds and two events at 10.0 seconds
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Building Your Script
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Drop your script into the scratch directory
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Now build your first example script using waf
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Building Your Script
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You can now run the example
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Building a Wireless Network Topology
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Add the Wifi and the mobility modules
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The network topology illustration follows:
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Building a Wireless Network Topology
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For enabling or disabling logging components
and for changing the number of devices created
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Building a Wireless Network Topology
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Part of the Wifi network
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Configure the PHY and channel helpers
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Yet Another Network Simulator
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
M. Lacage and T. R. Henderson, “Yet Another Network
Simulator,” WNS2 ns-2: The IP Network Simulator, Italy, 2006.
34
http://cutebugs.net/files/wns2-yans.pdf
Building a Wireless Network Topology

Create a channel object and associate it to our
PHY layer object manager
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NqosWifiMacHelper object to set MAC parameters
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rate control algorithm
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AARF (Adaptive Auto-Rate Fallback ) algorithm
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Building a Wireless Network Topology
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The SSID of the infrastructure network
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Create the wifi devices of these stations
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Building a Wireless Network Topology
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Configure the AP (access point) node
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Shares the same set of PHY-level Attributes
(and channel) as the stations
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Building a Wireless Network Topology
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Set some Attributes controlling the “position
allocator” functionality
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The number of objects layed
out on a line.
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Building a Wireless Network Topology

Need to tell them how to move
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RandomWalk2dMobilityModel
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random direction
random speed
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Rectangle (double _xMin, double _xMax, double _yMin,
double _yMax)
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Building a Wireless Network Topology
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Want the access point to remain in a fixed
position during the simulation
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Protocol stacks
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Building a Wireless Network Topology
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assign IP addresses to the device interfaces
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Building a Wireless Network Topology
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Enable internetwork routing
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Create just enough tracing to cover all three
networks
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Building a Wireless Network Topology
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Run the simulation, clean up and then exit the
program
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Output
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Read the pcap files
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Plot figures
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An Example of MANET
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Reference
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/ns-allinone-3.10/ns-3.10/examples/wireless/wifihidden-terminal.cc
Codes (1/7)
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Codes (2/7)
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Codes (3/7)
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Codes (4/7)
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Codes (5/7)
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Codes (6/7)
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Codes (7/7)
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Result
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Need to do…… (1/3)
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Transmission range of a node
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ns3::RangePropagationLossModel
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Node moving speed
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ns3::RandomWaypointMobilityModel
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MaxRange
Speed
Pause
Node data rate
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ns3::ConstantRateWifiManager
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Need to do…… (2/3)
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RTS retry limit
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ns3::UanMacRc
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Buffer size
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ns3::TcpSocket
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RetryRate
SndBufSize
AODV hello periods
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ns3::aodv::RoutingProtocol
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HelloInterval
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Need to do…… (3/3)
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Uniform distribution in a square with 500 meters
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ns3::RandomRectanglePositionAllocator
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ns3::UniformVariable
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Q&A
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