ns-3%20Training

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ns-3 Training

• Computer and Communication Network Lab
• Department of Electrical Engineering
• National Sun Yat-Sen University
• 5/13/2013

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Topics

• Getting Started ns-3
• What is ns-3?
• Installation
• A First ns-3 Script
• Two tutorial examples
• A simple example for this project
• Complete the remaining parts

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Getting Started ns-3

• Please read the following documents
• ns-3 overview
• http//www.nsnam.org/docs/ns-3-overview.ppt
• http//www.nsnam.org/docs/ns-3-overview.pdf
• ns-3 Tutorial
• http//www.nsnam.org/docs/release/3.13/tutorial/ns
  -3-tutorial.pdf
• ns-3 Manual
• http//www.nsnam.org/docs/release/3.13/manual/ns-3
  -manual.pdf

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What is ns-3?

• ns-3 is a discrete-event network simulator for
  Internet systems
• 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

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Extensible Software Core

• Written in C with optional Python interface
• extensively documented API (doxygen)
• http//www.nsnam.org/doxygen-release/index.html

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Node Basics

• 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)
• Problem Tracing needs vary widely
• 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

• ns-3 solution decouple trace sources from trace
  sinks
• 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.
• Network Simulation Cradle

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Building ns-3 (1/5)

• ./build.py

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Building ns-3 (2/5)

• ./waf -d optimized configure
• ns-3 uses the waf build system

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Building ns-3 (3/5)

• ./waf -d debug configure

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Building ns-3 (4/5)

• ./test.py -c core

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Building ns-3 (5/5)
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Running a Script

• ./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

• ./waf --run scratch/myfirst

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A First ns-3 Script

• /ns-allinone-3.10/ns-3.10/examples/tutorial
• first.cc
• third.cc

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Boilerplate

• The first line in the file is an emacs mode line.
• The ns-3 simulator is licensed using the GNU
  General Public License.

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Module Includes

• The code proper starts with a number of include
  statements.
• ../../build/debug/ns3

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Ns3 Namespace

• The next line in the first.cc script is a
  namespace declaration.
• Logging

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Main Functions

• The next lines of the script you will find are,

• ns3 ??? log ???????????
• NS_LOG_ERROR Log error messages
• NS_LOG_WARN Log warning messages
• NS_LOG_DEBUG Log relatively rare, ad-hoc
  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.

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Topology Helpers

• Create the ns-3 Node objects that will represent
  the computers in the simulation.
• We are constructing a point to point link

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Topology Helpers

• We will need to have a list of all of the
  NetDevice objects that are created

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Internet Stack Helper

• Protocol stacks installed on our nodes
• TCP, UDP, IP, etc.
• Ipv4AddressHelper
• make the association between an IP address and a
  device

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Applications

• Two specializations of the core ns-3 class
  Application called
• UdpEchoServerApplication
• UdpEchoClientApplication
• UdpEchoServerHelper

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Applications

• UdpEchoClientHelper

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Simulator

• What we need to do at this point is to actually
  run the simulation.
• 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

• Drop your script into the scratch directory
• Now build your first example script using waf

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Building Your Script

• You can now run the example

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Building a Wireless Network Topology

• Add the Wifi and the mobility modules
• The network topology illustration follows

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Building a Wireless Network Topology

• For enabling or disabling logging components and
  for changing the number of devices created

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Building a Wireless Network Topology

• Part of the Wifi network
• Configure the PHY and channel helpers
• Yet Another Network Simulator
• M. Lacage and T. R. Henderson, Yet Another
  Network Simulator, WNS2 ns-2 The IP Network
  Simulator, Italy, 2006.
• http//cutebugs.net/files/wns2-yans.pdf

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Building a Wireless Network Topology

• Create a channel object and associate it to our
  PHY layer object manager
• NqosWifiMacHelper object to set MAC parameters
• rate control algorithm
• AARF (Adaptive Auto-Rate Fallback ) algorithm

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Building a Wireless Network Topology

• The SSID of the infrastructure network
• Create the wifi devices of these stations

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Building a Wireless Network Topology

• Configure the AP (access point) node
• Shares the same set of PHY-level Attributes (and
  channel) as the stations

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Building a Wireless Network Topology

• Set some Attributes controlling the position
  allocator functionality

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
• RandomWalk2dMobilityModel
• random direction
• random speed
• Rectangle (double _xMin, double _xMax, double
  _yMin, double _yMax)

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Building a Wireless Network Topology

• Want the access point to remain in a fixed
  position during the simulation
• Protocol stacks

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Building a Wireless Network Topology

• assign IP addresses to the device interfaces

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Building a Wireless Network Topology

• Enable internetwork routing
• Create just enough tracing to cover all three
  networks

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Building a Wireless Network Topology

• Run the simulation, clean up and then exit the
  program
• Output

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Read the pcap files

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Plot figures

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An Example of MANET

• Reference
• /ns-allinone-3.10/ns-3.10/examples/wireless/wifi-h
  idden-terminal.cc

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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)

• Transmission range of a node
• ns3RangePropagationLossModel
• MaxRange
• Node moving speed
• ns3RandomWaypointMobilityModel
• Speed
• Pause
• Node data rate
• ns3ConstantRateWifiManager

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Need to do (2/3)

• RTS retry limit
• ns3UanMacRc
• RetryRate
• Buffer size
• ns3TcpSocket
• SndBufSize
• AODV hello periods
• ns3aodvRoutingProtocol
• HelloInterval

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Need to do (3/3)

• Uniform distribution in a square with 500 meters
• ns3RandomRectanglePositionAllocator
• ns3UniformVariable

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Q A